JP2018104359A - Organic compound, light emitting element, light emitting device, electronic apparatus, and illumination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel compound and also provide a light emitting element having excellent luminous efficiency and heat resistance.SOLUTION: The present invention provides a novel organic compound having a heteroaromatic ring and a carbazole skeleton, the carbazole skeleton having a substituent at position 2. There is also provided a light emitting element having the compound.SELECTED DRAWING: Figure 1

Description

  One embodiment of the present invention relates to a novel organic compound. Alternatively, the present invention relates to a compound having a substituent at the 2-position of the carbazole skeleton. Alternatively, the present invention relates to a synthesis method for the organic compound. Alternatively, the present invention relates to a light-emitting element, a light-emitting device, an electronic device, and a lighting device including the organic compound.

  Note that one embodiment of the present invention is not limited to the above technical field. One embodiment of the present invention relates to an object, a method, or a manufacturing method. Or this invention relates to a process, a machine, a manufacture, or a composition (composition of matter). In particular, one embodiment of the present invention relates to a semiconductor device, a light-emitting device, a display device, a lighting device, a light-emitting element, and manufacturing methods thereof.

  Practical use of light-emitting elements (organic EL elements) using electroluminescence (EL) using organic compounds has been progressing. The basic structure of these light-emitting elements is such that an organic compound layer (EL layer) containing a light-emitting material is sandwiched between a pair of electrodes. Light emission from the light-emitting material can be obtained by applying a voltage to this element, injecting carriers, and utilizing the recombination energy of the carriers.

  Since such a light-emitting element is a self-luminous type, when used as a pixel of a display, there are advantages such as high visibility and no need for a backlight, and it is suitable as a flat panel display element. In addition, a display using such a light emitting element has a great advantage that it can be manufactured to be thin and light. Another feature is that the response speed is very fast.

  In addition, since these light emitting elements can continuously form a light emitting layer in two dimensions, light emission can be obtained in a planar shape. This is a feature that is difficult to obtain with a point light source typified by an incandescent bulb or LED, or a line light source typified by a fluorescent lamp. In addition, since light emitted from an organic compound can be emitted without containing ultraviolet light by selecting a material, the utility value as a surface light source applicable to illumination or the like is also high.

  Since displays and lighting devices using organic EL elements are suitable for various electronic devices as described above, research and development are being pursued for light-emitting elements having better efficiency and element lifetime. In particular, organic compounds are mainly used for the EL layer, which has a great influence on the improvement of device characteristics of light-emitting elements, and therefore various new organic compounds have been developed.

As an organic compound that can be used for the light-emitting element, an organic compound having a carbazole skeleton can be given (for example, Patent Document 1). In order to improve the heat resistance and carrier (electron or hole) transport properties of an organic compound having a carbazole skeleton, it is useful to introduce a substituent. There may be a decrease in efficiency and a decrease in reliability.

JP 2013-47283 A

  Therefore, an object of one embodiment of the present invention is to provide a novel organic compound. In particular, an object is to provide an organic compound having a substituent at the 2-position of the carbazole skeleton. Alternatively, the present invention relates to a method for synthesizing an organic compound having a substituent at the 2-position of a carbazole skeleton. Another object is to provide an organic compound with favorable heat resistance. Another object is to provide a light-emitting element with favorable light emission efficiency. Another object is to provide a light-emitting element with low driving voltage.

Note that the description of the above problems does not disturb the existence of other problems. Note that one embodiment of the present invention does not necessarily have to solve all of these problems. Problems other than the above are obvious from the description of the specification and the like, and problems other than the above can be extracted from the description of the specification and the like.

One embodiment of the present invention is an aromatic compound having a substituent at the 2-position of the carbazole skeleton.

  Therefore, one embodiment of the present invention is an organic compound represented by General Formula (G0) below.

However, in General Formula (G0), A represents a nitrogen-containing heteroaromatic ring, and any one of B ^{1 to} B ⁴ is an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted carbon number of 3 to 7 And R ^{1 to} R ¹² are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted group. Any one of a substituted aryl group having 6 to 13 carbon atoms, Ar ¹ and Ar ² each independently represents a substituted or unsubstituted arylene group having 6 to 25 carbon atoms, and n and k are 0 to 3 Represents an integer, and m represents an integer of 1 to 3. )

Another embodiment of the present invention is an organic compound represented by General Formula (G1).

However, in General Formula (G1), A represents a nitrogen-containing heteroaromatic ring, and any one of B ^{1 to} B ⁴ is an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted carbon number of 3 to 7 The others are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted carbon group having 6 to 6 carbon atoms. Any one of 13 aryl groups, Ar ¹ and Ar ² each independently represents a substituted or unsubstituted arylene group having 6 to 25 carbon atoms, n and k each represents an integer of 0 to 3, and m is Represents an integer of 1 to 3;

Another embodiment of the present invention is an organic compound represented by General Formula (G2).

However, in General Formula (G2), A represents a nitrogen-containing heteroaromatic ring, and any one of B ^{1 to} B ⁴ is an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted C 3 to 7 carbon atoms. Each of the others independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted carbon group having 6 to 13 carbon atoms. N and k each represents an integer of 0 to 3, and m represents an integer of 1 to 3.

Another embodiment of the present invention is an organic compound represented by General Formula (G3).

However, in General Formula (G3), A represents a nitrogen-containing heteroaromatic ring, and any one of B ^{1 to} B ⁴ is an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted carbon number of 3 to 7 The others are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted carbon group having 6 to 6 carbon atoms. Any one of 13 aryl groups.

In the above structure, A is preferably a nitrogen-containing heteroaromatic ring having 1 to 5 carbon atoms. More preferably, any one of pyridine, diazine, and triazine is used.

In the above structure, any one of B ^{1 to} B ⁴ is preferably a methyl group.

Another embodiment of the present invention is an organic compound represented by Structural Formula (100).

Another embodiment of the present invention is a light-emitting element including the above organic compound.

Another embodiment of the present invention is an organic compound represented by Structural Formulas (500) and (501).

  Another embodiment of the present invention is an electronic device including the light-emitting element having the above structure and at least one of a housing and a touch sensor. Another embodiment of the present invention is a lighting device including the light-emitting element having any of the above structures and at least one of a housing, a connection terminal, and a protective cover. One embodiment of the present invention includes not only a light-emitting device including a light-emitting element but also an electronic device including the light-emitting device. Therefore, a light-emitting device in this specification refers to an image display device or a light source (including a lighting device). In addition, a display module in which a connector such as an FPC (Flexible Printed Circuit) or TCP (Tape Carrier Package) is attached to the light emitting device, a display module in which a printed wiring board is provided at the end of TCP, or a COG (Chip On) in the light emitting element. A display module in which an IC (integrated circuit) is directly mounted by a glass method is also an embodiment of the present invention.

According to one embodiment of the present invention, a novel organic compound can be provided. In particular, an organic compound having a substituent at the 2-position of the carbazole skeleton can be provided. A method for synthesizing an organic compound having a substituent at the 2-position of the carbazole skeleton can be provided. Alternatively, an organic compound with favorable heat resistance can be provided. Alternatively, a light-emitting element with favorable light emission efficiency can be provided. Alternatively, a light-emitting element with low driving voltage can be provided.

  Note that the description of these effects does not disturb the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. Note that the effects other than these are obvious from the description of the specification, drawings, claims, and the like, and it is possible to extract other effects from the descriptions of the specification, drawings, claims, and the like.

6A and 6B illustrate a HOMO distribution of an organic compound according to one embodiment of the present invention. FIGS. 3A and 3B are a schematic cross-sectional view of a light-emitting element of one embodiment of the present invention and a schematic diagram illustrating a correlation between energy levels of a light-emitting layer. FIG. 9 is a schematic cross-sectional view of a light-emitting element of one embodiment of the present invention. 1 is a conceptual diagram of an active matrix light-emitting device according to one embodiment of the present invention. 1 is a conceptual diagram of an active matrix light-emitting device according to one embodiment of the present invention. 1 is a conceptual diagram of an active matrix light-emitting device according to one embodiment of the present invention. 1 is a schematic diagram of an electronic device according to one embodiment of the present invention. 1 is a schematic diagram of an electronic device according to one embodiment of the present invention. FIG. 10 illustrates a lighting device according to one embodiment of the present invention. FIG. 10 illustrates a lighting device according to one embodiment of the present invention. The figure explaining the NMR chart of the compound based on an Example. The figure explaining the MS spectrum of the compound based on an Example. The figure explaining the absorption spectrum and emission spectrum in the solution of the compound based on an Example. The figure explaining the absorption spectrum and emission spectrum in the thin film state of the compound based on an Example. 6A and 6B illustrate current efficiency-luminance characteristics of a light-emitting element according to an example. 8A and 8B illustrate luminance-voltage characteristics of a light-emitting element according to an example. 6A and 6B illustrate an external quantum efficiency-luminance characteristic of a light-emitting element according to an example. 6A and 6B illustrate an emission spectrum of a light-emitting element according to an example.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and various changes can be made in form and details without departing from the spirit and scope of the present invention. Therefore, the present invention is not construed as being limited to the description of the embodiments below.

  Note that the position, size, range, and the like of each component illustrated in the drawings and the like may not represent the actual position, size, range, or the like for easy understanding. Therefore, the disclosed invention is not necessarily limited to the position, size, range, or the like disclosed in the drawings and the like.

  In this specification and the like, ordinal numbers attached as the first and second are used for convenience and may not indicate the order of steps or the order of lamination. Therefore, for example, the description can be made by appropriately replacing “first” with “second” or “third”. In addition, the ordinal numbers described in this specification and the like may not match the ordinal numbers used to specify one embodiment of the present invention.

  Further, in this specification and the like, in describing the structure of the invention with reference to drawings, the same reference numerals may be used in common among different drawings.

  In this specification and the like, the terms “film” and “layer” can be interchanged with each other. For example, the term “conductive layer” may be changed to the term “conductive film”. Alternatively, for example, the term “insulating film” may be changed to the term “insulating layer” in some cases.

Note that in this specification and the like, a singlet excited state (S ^* ) is a singlet state having excitation energy. The S1 level is the lowest singlet excitation energy level, and is the lowest singlet excited state (S1 state) excitation energy level. The triplet excited state (T ^* ) is a triplet state having excitation energy. The T1 level is the lowest triplet excitation energy level, and is the lowest triplet excited state (T1 state) excitation energy level. Note that in this specification and the like, even when expressed simply as a singlet excited state and a singlet excited energy level, the S1 state and the S1 level may be represented. Further, even when expressed as a triplet excited state and a triplet excited energy level, the T1 state and the T1 level may be expressed in some cases.

  In this specification and the like, a fluorescent compound is a substance that emits light in the visible light region when relaxing from a singlet excited state to a ground state. On the other hand, a phosphorescent compound is a substance that emits light in the visible light region at room temperature when relaxing from a triplet excited state to a ground state. In other words, a phosphorescent compound is one of substances that can convert triplet excitation energy into visible light.

  Note that in this specification and the like, room temperature refers to any temperature between 0 ° C. and 40 ° C.

  In this specification and the like, a blue wavelength region is a wavelength region of 400 nm to less than 500 nm, and blue light emission is light emission having at least one emission spectrum peak in the region. The green wavelength region is a wavelength region of 500 nm or more and less than 580 nm, and the green light emission is light emission having at least one emission spectrum peak in the region. The red wavelength region is a wavelength region of 580 nm or more and 680 nm or less, and the red light emission is light emission having at least one emission spectrum peak in the region.

(Embodiment 1)

One embodiment of the present invention is an aromatic compound having a substituent at the 2-position of the carbazole skeleton.

  Therefore, one embodiment of the present invention is an organic compound represented by General Formula (G0) below.

However, in General Formula (G0), A represents a nitrogen-containing heteroaromatic ring, and any one of B ^{1 to} B ⁴ is an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted carbon number of 3 to 7 And R ^{1 to} R ¹² are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted group. Any one of a substituted aryl group having 6 to 13 carbon atoms, Ar ¹ and Ar ² each independently represents a substituted or unsubstituted arylene group having 6 to 25 carbon atoms, and n and k are 0 to 3 Represents an integer, and m represents an integer of 1 to 3. )

In General Formula (G0), A represents a nitrogen-containing heteroaromatic ring, and is preferably a substituted or unsubstituted pyridine ring, a substituted or unsubstituted diazine ring, or a substituted or unsubstituted triazine ring. In this case, when used as an electron transporting material (for example, a host or an electron transporting layer of an organic EL light-emitting layer) in an electronic device, the LUMO of the organic compound according to one embodiment of the present invention is distributed around A. Is injected around A. Therefore, when a substituent is introduced without changing the electron injection property as much as possible, the introduction position is preferably a skeleton having a low electron transport property. Specifically, in the general formula (G0), the substituent is preferably introduced into a carbazolyl group having a LUMO level lower than that of A. In this case, a structure having two carbazolyl groups in one molecule is particularly preferable because it has good heat resistance and can introduce a substituent into each carbazolyl group. Further, when the carbazolyl group is bonded to Ar ¹ or Ar ^{2 at the} 9-position, the HOMO level is deeper than that bonded at other substitution positions (positions 1 to 8), and the S1 level or the T1 level Is preferable.

Another embodiment of the present invention is an organic compound represented by General Formula (G1).

However, in General Formula (G1), A represents a nitrogen-containing heteroaromatic ring, and any one of B ^{1 to} B ⁴ is an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted carbon number of 3 to 7 The others are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted carbon group having 6 to 6 carbon atoms. Any one of 13 aryl groups, Ar ¹ and Ar ² each independently represents a substituted or unsubstituted arylene group having 6 to 25 carbon atoms, n and k each represents an integer of 0 to 3, and m is Represents an integer of 1 to 3;

Another embodiment of the present invention is an organic compound represented by General Formula (G2).

However, in General Formula (G2), A represents a nitrogen-containing heteroaromatic ring, and any one of B ^{1 to} B ⁴ is an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted C 3 to 7 carbon atoms. Each of the others independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted carbon group having 6 to 13 carbon atoms. N and k each represents an integer of 0 to 3, and m represents an integer of 1 to 3.

Another embodiment of the present invention is an organic compound represented by General Formula (G3).

However, in General Formula (G3), A represents a nitrogen-containing heteroaromatic ring, and any one of B ^{1 to} B ⁴ is an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted carbon number of 3 to 7 The others are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted carbon group having 6 to 6 carbon atoms. Any one of 13 aryl groups.

In the above structure, A is preferably a nitrogen-containing heteroaromatic ring having 1 to 5 carbon atoms. In particular, any one of pyridine, diazine, and triazine is more preferable because it has a high T1 level and high electron transport properties.

In the above structure, any one of B ^{1 to} B ⁴ is preferably a methyl group because synthesis is facilitated.

In the above structure, when Ar ¹ and Ar ² are phenyl groups, the phenyl groups are preferably bonded to the carbazole skeleton and the nitrogen-containing heteroaromatic ring at the meta position. Bonding at the meta position is preferable because an organic compound having a high T1 level can be obtained.

Another embodiment of the present invention is an organic compound represented by Structural Formula (100).

Another embodiment of the present invention is an organic compound represented by Structural Formulas (500) and (501).

The organic compounds represented by the structural formulas (500) and (501) can be suitably used as a raw material for an organic compound having a substituent at the 2-position of the carbazole skeleton. By synthesizing an organic compound having a substituent at the 2-position of the carbazole skeleton using the organic compounds represented by (500) and (501), the target product can be obtained simply and with high yield.

<Examples of substituents>
In General Formulas (G0) to (G4), a substituted or unsubstituted arylene group having 6 to 25 carbon atoms represented by Ar ¹ and Ar ² is represented. Examples of the arylene group include a phenylene group, a naphthylene group, A biphenyldiyl group, a fluorenediyl group, a spiro fluorenediyl group, etc. are mentioned. More specifically, for example, groups represented by the following structural formulas (Ar-1) to (Ar-27) can be applied. In addition, the group represented by Ar is not limited to these, You may have a substituent.

In general formulas (G0) to (G4), hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cyclohexane having 3 to 7 carbon atoms represented by B ^{1 to} B ⁴ and R ^{1 to} R ¹² It represents an alkyl group or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, and an n-hexyl group. Examples of the cycloalkyl group include a cyclo group. A propyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and the like can be given. Examples of the aryl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. More specifically, examples include groups represented by the following structural formulas (R-1) to (R-27). The groups represented by B ^{1 to} B ⁴ and R ^{1 to} R ¹² are not limited to these.

At this time, a saturated aliphatic hydrocarbon group such as an alkyl group or a cycloalkyl group such as the structural formulas (R-1) to (R-15) has higher solubility in an organic solvent, and S1 and T1. Is preferable. An aromatic hydrocarbon group such as the above structural formulas (R-16) to (R-27) is preferable because it can be expected that there is little chemical change to redox.

<Specific examples of compounds>
As specific structures of the compounds represented by the general formulas (G0) to (G4), compounds represented by the following structural formulas (101) to (152) can be given. Note that the compounds represented by the general formulas (G0) to (G4) are not limited to the following examples.

In the general formulas (G0) to (G2), when m, n, and k are each 2 or more, A, Ar ¹ , and Ar ² may not be repeating the same unit. For example, in the structural formula (113), Ar ¹ is a combination of a phenylene group and a methylphenylene group, the structural formula (114) is a combination of A is a pyridylene group and a pyrimidylene group, and the structural formula (115) is a 2,4-pyridylene. The structural formula (117) is a combination of a pyridylene group and a pyrazylene group.

Since the organic compound according to one embodiment of the present invention has a nitrogen-containing heteroaromatic ring, the performance is excellent in carrier transportability. In addition, since it has a high S1 level or T1 level, it can be suitably used as a host material for a light-emitting element in the visible region. Therefore, by using the organic compound according to one embodiment of the present invention for a light-emitting element, a light-emitting element with low driving voltage and favorable light emission efficiency can be provided.

A characteristic required for an organic compound used for a light-emitting element is heat resistance. Considering the glass transition point (Tg) of the material as an index, it can be said that the higher the Tg, the better the heat resistance. Tg generally tends to increase as the molecular weight increases. Therefore, in order to improve the heat resistance, it is conceivable to introduce a substituent into the skeleton of the organic compound in order to increase the molecular weight.

When a substituent is introduced into the skeleton of an organic compound, depending on the substitution position and the type of the substituent, the carrier transport property and triplet excitation level (T1 level) of the organic compound may be reduced. The device characteristics may be adversely affected.

Here, in the case of introducing a substituent into the carbazole skeleton, the present inventor introduces a hydrocarbon group, preferably a saturated aliphatic hydrocarbon group, at the 2-position of the carbazole skeleton, thereby adversely affecting the material and the light emitting device characteristics. It has been found that the heat resistance can be improved by increasing the molecular weight of the organic compound without affecting.

The hydrocarbon group is preferably an alkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms. In particular, a methyl group is preferable because synthesis is easy.

In the organic compound according to one embodiment of the present invention, the nitrogen-containing heteroaromatic ring and the carbazole skeleton having a substituent at the 2-position are preferably bonded through an arylene group. With such a structure, a material having high S1 level and T1 level and heat resistance can be obtained.

In the organic compound according to one embodiment of the present invention, the nitrogen-containing heteroaromatic ring preferably has a 6-membered ring structure. More preferred are pyridine, diazine, and triazine. By using an organic compound having such a structure for a light-emitting element, a light-emitting element with excellent electron transportability and high reliability can be provided.

<Analysis of material properties by substitution position using quantum chemistry calculation>
Here, changes in material properties depending on the substitution position when a substituent is introduced into the carbazole skeleton will be described below using quantum chemical calculations.

The compounds used in this analysis are shown as compounds A1 to A5. Compound A1 is 9-phenyl-9H-carbazole (hereinafter referred to as PCz). Compound A2 is a compound in which a methyl group is introduced into position 1 of the carbazole skeleton of PCz, Compound A3 is a compound in which a methyl group is introduced into position 2 of the carbazole skeleton of PCz, and Compound A4 is position 3 of the carbazole skeleton of PCz. Compound A5 is a compound in which a methyl group is introduced at the 4-position of the carbazole skeleton of PCz.

Analysis of the highest occupied orbital (also referred to as Highest Occupied Molecular Orbital, HOMO) levels and HOMO orbitals of the compounds A1 to A5 was performed. As a calculation method, vibration (spin density) analysis in the most stable structure in which the S0 level is the lowest was performed for the singlet ground state (S0) of each compound. The calculation method used was a density functional method (DFT). The total energy of DFT is represented by the sum of potential energy, electrostatic energy between electrons, exchange correlation energy including all interactions between kinetic energy of electrons and complex electrons. In DFT, the exchange correlation interaction is approximated by a functional of one electron potential expressed by electron density (meaning a function of a function), and thus the calculation is fast. Here, the weight of each parameter related to exchange and correlation energy is defined using B3LYP which is a mixed functional. Moreover, 6-311G (d, p) was used as a basis function. Gaussian 09 was used as the calculation program. The results are shown in FIG.

In FIG. 1, the shadows in the molecules indicate the distribution of HOMO orbitals in the molecules (A1) to (A5). FIG. 1 shows that the distribution density of the HOMO orbitals on the carbon at the 2-position of the carbazole skeleton is low. That is, it was suggested that when a substituent is present at the 2-position of the carbazole skeleton as in Compound A3, it is difficult to be affected by the substituent.

In addition, Table 1 shows that when Compound A2 to Compound A5 in which a methyl group is introduced into PCz are compared, Compound A3 having a methyl group at the 2-position of the carbazole skeleton has the lowest HOMO level.

In the light emitting layer of the light emitting element, a host material and a guest material may be mixed, and an electron transporting material and a hole transporting material may be mixed in the host material. In this case, the HOMO level of the electron transporting material is preferably lower than the HOMO level of the hole transporting material. When the HOMO level of the electron transporting material is higher than the HOMO level of the hole transporting material, the electron transporting material becomes a hole injection barrier, so that the driving voltage is increased. Therefore, when an electron transporting material and a hole transporting material are used for the light-emitting layer, it is preferable that the electron transporting material has a low HOMO level.

When the light emitting layer is a combination of a hole transporting material and an electron transporting material, the carrier balance can be easily controlled by the mixing ratio. Specifically, a hole transporting material: electron transporting material = 1: 9 to 9: 1 (weight ratio) is preferable.

An electron-transporting material with low HOMO is preferable because it can form a hole-injection barrier at the interface between the light-emitting layer and the electron-transporting layer when applied to the electron-transporting layer. In this case, hole injection into the electron transport layer can be suppressed, and the light emission efficiency of the light emitting element can be improved.

Since an alkyl group such as a methyl group is an electron donating group, when introduced as a substituent into an organic compound, the charge density of the introduced skeleton is increased, and thus the HOMO level is expected to be high. Since compound A3 having a substituent at the position has a small distribution density of HOMO orbitals from FIG. 1, the amount of increase in the HOMO level when a methyl group is introduced is other substitution positions, that is, position 1 of the carbazole skeleton, Smaller than the third and fourth place. That is, it was suggested that the methyl group can be introduced while having the same HOMO level as the compound A1 having no methyl group. In other words, when an alkyl group is introduced into the carbazole skeleton, by introducing an alkyl group at the 2-position, the molecular weight can be increased while having a low HOMO level, and the heat resistance of the organic compound is improved. Can do. Also, when alkyl is introduced at the 7-position, it is expected that the same effect as when an alkyl group is introduced at the 2-position is obtained.

Moreover, although the quantum chemistry calculation was performed about the case where a substituent is a methyl group above, the said effect is not restricted to a methyl group. A similar effect is expected when the substituent is an electron donating group such as a saturated hydrocarbon group.

Note that the organic compound in this embodiment can be formed by a deposition method (including a vacuum deposition method), an inkjet method, a coating method, a gravure printing method, or the like.

Note that this embodiment can be combined with any of the other embodiments as appropriate.

(Embodiment 2)
In this embodiment, a method for synthesizing the organic compound represented by General Formula (G0) which is one embodiment of the present invention will be described.

The compound represented by the following general formula (G0) can be synthesized by the following simple synthesis scheme.

For example, as shown in the following scheme (F1), the carbazole compound (a1) and the dihalogen compound (a2) are coupled to obtain the halide represented by (a3). At this time, X ¹ and X ² each represent halogen.

This reaction has various conditions. As an example, a synthesis method using a metal catalyst in the presence of a base can be applied. For example, the Buchwald-Hartwig reaction or the Ullmann reaction can be used.

Next, as shown in Scheme (F2), a boron compound (a4) is obtained by reacting a boric acid ester with a compound activated by reacting the halide (a3) with a metal catalyst. At this time, Z ¹ represents boronic acid or dialkoxyboron.
As an example of the activation, a reaction of lithiation with an alkyl lithium reagent in an ether solvent, or a reaction using magnesium as a grinder reagent can be used.

Next, as shown in the scheme (F3), a boron compound (a4) and a dihalogen compound (a5) are coupled to obtain a halide represented by (a4). At this time, X ³ and X ⁴ each represent halogen.

This reaction has various conditions. As an example, a synthesis method using a metal catalyst in the presence of a base can be applied. For example, the Suzuki-Miyaura reaction can be used.

Next, as shown in Scheme (F4), by coupling a halogen compound (a6) and an aryl boron compound (a7), a compound represented by (G0) which is the target product can be obtained. At this time, Z ² represents boronic acid or dialkoxyboron.

This reaction has various conditions. As an example, a synthesis method using a metal catalyst in the presence of a base can be applied. For example, the Suzuki-Miyaura reaction can be used.

In addition, when at least a portion other than the reactive group (Z ¹ or Z ² ) of the compound (a6) and the compound (a7) is the same, the compound (a4) is equivalent to the compound (a5) in the scheme (F3) The reaction is preferable because it requires fewer synthesis steps. Further, since at least B ¹ and B ³ have substituents, a compound having high thermophysical properties can be obtained easily and is preferable.

In the above general formulas (G0) and (a1) to (a7), A represents a nitrogen-containing heteroaromatic ring, and any one of B ^{1 to} B ⁴ represents an alkyl group having 1 to 6 carbon atoms, Represents a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, and the others and R ^{1 to} R ¹² each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted carbon group having 3 to 7 carbon atoms. 7 or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and Ar ¹ and Ar ² each independently represents a substituted or unsubstituted arylene group having 6 to 25 carbon atoms. N, k represents an integer of 0 to 3, and m represents an integer of 1 to 3.

In the synthesis of the organic compound (G0) of the present invention, the synthesis method is not limited to the synthesis schemes (F1) to (F4).

(Embodiment 3)
In Embodiment, a light-emitting element of one embodiment of the present invention will be described below with reference to FIGS.

<Configuration example of light emitting element>
First, the structure of the light-emitting element of one embodiment of the present invention is described below with reference to FIGS.

  FIG. 2A is a schematic cross-sectional view of the light-emitting element 150 of one embodiment of the present invention.

  The light-emitting element 150 includes a pair of electrodes (the electrode 101 and the electrode 102) and the EL layer 100 provided between the pair of electrodes. The EL layer 100 includes at least a light emitting layer 140.

  In addition to the light-emitting layer 140, the EL layer 100 illustrated in FIG. 2A includes functional layers such as a hole injection layer 111, a hole transport layer 112, an electron transport layer 118, and an electron injection layer 119.

  Note that in this embodiment, of the pair of electrodes, the electrode 101 is an anode and the electrode 102 is a cathode, but the structure of the light-emitting element 152 is not limited thereto. That is, the electrode 101 may be a cathode, the electrode 102 may be an anode, and the layers stacked between the electrodes may be reversed. In other words, the hole injection layer 111, the hole transport layer 112, the light-emitting layer 140, the electron transport layer 118, and the electron injection layer 119 may be stacked in this order from the anode side.

  Note that the structure of the EL layer 100 is not limited to the structure shown in FIG. 2A, and is selected from the hole injection layer 111, the hole transport layer 112, the electron transport layer 118, and the electron injection layer 119. What is necessary is just to set it as the structure which has at least one. Alternatively, the EL layer 100 reduces a hole or electron injection barrier, improves a hole or electron transport property, inhibits a hole or electron transport property, or suppresses a quenching phenomenon caused by an electrode. It is good also as a structure which has a functional layer which has the function of being able to do. Note that each functional layer may be a single layer or a structure in which a plurality of layers are stacked.

The light-emitting element 150 only needs to include the organic compound according to one embodiment of the present invention in any layer of the EL layer 100. Note that the layer containing the organic compound is preferably the electron transporting layer 118 or more preferably the light emitting layer 140.

  FIG. 2B is a schematic cross-sectional view illustrating an example of the light-emitting layer 140 illustrated in FIG. A light-emitting layer 140 illustrated in FIG. 2B includes a host material 141 and a guest material 142. The host material 141 includes an organic compound 141_1 and an organic compound 141_2.

  The guest material 142 may be a light-emitting organic material. The light-emitting organic material may be a material that can emit fluorescence (hereinafter referred to as a fluorescent material) or a material that can emit phosphorescence. (Hereinafter also referred to as phosphorescent material). In the following description, a structure in which a phosphorescent material is used as the guest material 142 will be described. Note that the guest material 142 may be read as a phosphorescent material.

  In the case where two types of host materials such as the organic compound 141_1 and the organic compound 141_2 are used for the light emitting layer as shown in FIG. 2B (co-host system), in general, the two types of host materials include Each of the electron transporting material and the hole transporting material is used. Such a configuration can reduce the driving voltage because the hole injection barrier between the hole transport layer 112 and the light emitting layer 140 and the electron injection barrier between the electron transport layer 118 and the light emitting layer 140 are reduced. Since it is possible, it is a preferable structure.

<Light emitting mechanism of light emitting element>
Next, the light emission mechanism of the light emitting layer 140 will be described below.

  The organic compound 141_1 and the organic compound 141_2 included in the host material 141 in the light-emitting layer 140 form an exciplex (also referred to as an exciplex, exciplex, or exciplex).

FIG. 2C illustrates the correlation of energy levels among the organic compound 141_1, the organic compound 141_2, and the guest material 142 in the light-emitting layer 140. In addition, the notation and code | symbol in FIG.2 (C) are as follows.
Host (141_1): Organic compound 141_1 (host material)
Host (141_2): Organic compound 141_2 (host material)
Guest (142): Guest material 142 (phosphorescent compound)
· _{S PH1:} organic compound 141_1 (host material) of the S1 level _{· T PH1:} organic compound 141_1 (host material) of the T1 level _{· S PH2:} organic compound 141_2 (host material) of the S1 level _{· T PH2:} Organic T1 level · _{S PG} compounds 141_2 (host material): guest material 142 (phosphorescent compound) of S1 level · _{T PG:} guest material 142 (phosphorescent compound) of T1 level · _{S PE:} exciplex S1 Level / T _PE : T1 level of exciplex

The organic compound 141_1 and the organic compound 141_2 form an exciplex, and the S1 level (S _PE ) and the T1 level (T _PE ) of the exciplex are adjacent to each other (FIG. 2C, route E ₁ reference).

One of the organic compound 141_1 and the organic compound 141_2 quickly forms an exciplex by receiving holes and receiving electrons by the other. Alternatively, when one is in an excited state, it rapidly interacts with the other to form an exciplex. Therefore, most excitons in the light-emitting layer 140 exist as exciplexes. The excitation energy level (S _PE or T _PE ) of the exciplex is lower than the S1 level (S _PH1 and S _PH2 ) of the host material (organic compound 141_1 and organic compound 141_2) that forms the exciplex. The excited state of the host material 141 can be formed with the excitation energy. As a result, the driving voltage of the light emitting element can be lowered.

Then, the energy of both the (S _PE ) and (T _PE ) of the exciplex is transferred to the T1 level of the guest material 142 (phosphorescent compound), and light emission is obtained (FIG. 2 (C) Route E ₂ , E reference _3).

Note that the T1 level (T _PE ) of the exciplex is preferably larger than the T1 level (T _PG ) of the guest material 142. By doing so, the singlet excitation energy and triplet excitation energy of the generated exciplex are changed from the S1 level (S _PE ) and T1 level (T _PE ) of the exciplex to the T1 level (T _PG ) of the guest material 142. ) To transfer energy.

In addition, in order to efficiently transfer excitation energy from the exciplex to the guest material 142, the T1 level (T _PE ) of the exciplex corresponds to each organic compound (organic compound 141_1 and organic compound 141_2) that forms the exciplex. It is preferable that it is equal to or smaller than the T1 level ( _TPH1 and _TPH2 ). Thereby, quenching of triplet excitation energy of the exciplex by each organic compound (organic compound 141_1 and organic compound 141_2) is less likely to occur, and energy transfer from the exciplex to the guest material 142 efficiently occurs.

  Further, when the combination of the organic compound 141_1 and the organic compound 141_2 is a combination of a compound having a hole transporting property and a compound having an electron transporting property, the carrier balance can be easily controlled by the mixture ratio. Become. Specifically, a compound having a hole transport property: a compound having an electron transport property = 1: 9 to 9: 1 (weight ratio) is preferable. In addition, since the carrier balance can be easily controlled by having this configuration, the carrier recombination region can be easily controlled.

Note that the processes of the routes E ₂ and E ₃ described above may be referred to as ExTET (Exciplex-Triple Energy Transfer) in this specification and the like. In other words, the light-emitting layer 140 provides excitation energy from the exciplex to the guest material 142. Note that this is not necessarily the reverse intersystem crossing efficiency from T _PE to S _PE is high when, because there is no great need emission quantum yield from SPE, it is possible to widely select a material.

  The combination of the organic compound 141_1 and the organic compound 141_2 may be a combination capable of forming an exciplex, but one has a HOMO level lower than the other HOMO level and the other lowest empty It is preferable to have a LUMO level lower than orbital (also referred to as a Lowest Unoccupied Molecular Orbital, LUMO) level.

<Material>
Next, details of components of the light-emitting element according to one embodiment of the present invention are described below.

≪Luminescent layer≫
In the light emitting layer 140, the host material 141 is present in the largest amount by weight, and the guest material 142 is dispersed in the host material 141. When the guest material 142 is a fluorescent compound, the S1 level of the host material 141 (the organic compound 141_1 and the organic compound 141_2) of the light-emitting layer 140 is higher than the S1 level of the guest material (guest material 142) of the light-emitting layer 140. It is preferable. In the case where the guest material 142 is a phosphorescent compound, the T1 level of the host material 141 (the organic compound 141_1 and the organic compound 141_2) of the light-emitting layer 140 is higher than the T1 level of the guest material (guest material 142) of the light-emitting layer 140. Is preferably high.

The organic compound 141_1 is preferably a compound having a nitrogen-containing six-membered heteroaromatic skeleton. In particular, the organic compound according to one embodiment of the present invention can be preferably used. Specific examples include compounds having a pyridine skeleton, a diazine skeleton (pyrazine skeleton, pyrimidine skeleton, and pyridazine skeleton), and a triazine skeleton. Examples of the compound having a basic nitrogen-containing heteroaromatic skeleton include compounds such as pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, triazine derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, phenanthroline derivatives, and purine derivatives. . As the organic compound 141_1, a material having an electron transport property higher than that of holes (electron transport material) can be used, and the material has an electron mobility of 1 × 10 ⁻⁶ cm ² / Vs or more. It is preferable.

Specifically, for example, heterocyclic compounds having a pyridine skeleton such as bathophenanthroline (abbreviation: BPhen), bathocuproin (abbreviation: BCP), and 2- [3- (dibenzothiophen-4-yl) phenyl] dibenzo [f , H] quinoxaline (abbreviation: 2mDBTPDBq-II), 2- [3 ′-(dibenzothiophen-4-yl) biphenyl-3-yl] dibenzo [f, h] quinoxaline (abbreviation: 2mDBTPBPDBq-II), 2- [ 3 ′-(9H-carbazol-9-yl) biphenyl-3-yl] dibenzo [f, h] quinoxaline (abbreviation: 2mCzBPDBq), 2- [4- (3,6-diphenyl-9H-carbazol-9-yl) ) Phenyl] dibenzo [f, h] quinoxaline (abbreviation: 2CzPDBq-III), 7- [3- (diben) Thiophen-4-yl) phenyl] dibenzo [f, h] quinoxaline (abbreviation: 7mDBTPDBq-II) and 6- [3- (dibenzothiophen-4-yl) phenyl] dibenzo [f, h] quinoxaline (abbreviation: 6mDBTPDBq-II), (2- [3- (3,9′-bi-9H-carbazol-9-yl) phenyl] dibenzo [f, h] quinoxaline) (abbreviation: 2mCzCzPDBq), 4,6-bis [3 -(Phenanthrene-9-yl) phenyl] pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis [3- (4-dibenzothienyl) phenyl] pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6- Diazis such as bis [3- (9H-carbazol-9-yl) phenyl] pyrimidine (abbreviation: 4,6mCzP2Pm) A heterocyclic compound having a skeleton, 2- {4- [3- (N-phenyl-9H-carbazol-3-yl) -9H-carbazol-9-yl] phenyl} -4,6-diphenyl-1,3 , 5-triazine (abbreviation: PCCzPTzn) and other heterocyclic compounds having a triazine skeleton, 3,5-bis [3- (9H-carbazol-9-yl) phenyl] pyridine (abbreviation: 35DCzPPy), 1,3, A heterocyclic compound having a pyridine skeleton such as 5-tri [3- (3-pyridyl) phenyl] benzene (abbreviation: TmPyPB) can also be used. Among the heterocyclic compounds described above, a heterocyclic compound having a triazine skeleton, a diazine (pyrimidine, pyrazine, pyridazine) skeleton, or a pyridine skeleton is preferable because it is stable and reliable. In addition, the heterocyclic compound having the skeleton has a high electron transporting property and contributes to a reduction in driving voltage. In addition, poly (2,5-pyridinediyl) (abbreviation: PPy), poly [(9,9-dihexylfluorene-2,7-diyl) -co- (pyridine-3,5-diyl)] (abbreviation: PF -Py), poly [(9,9-dioctylfluorene-2,7-diyl) -co- (2,2′-bipyridine-6,6′-diyl)] (abbreviation: PF-BPy) Molecular compounds can also be used. The substances mentioned here are mainly substances having an electron mobility of 1 × 10 ⁻⁶ cm ² / Vs or higher. Note that other than the above substances, any substance that has a property of transporting more electrons than holes may be used.

As the organic compound 141_2, a compound having a nitrogen-containing five-membered heterocyclic skeleton or a tertiary amine skeleton is preferable. Specific examples include a pyrrole skeleton or an aromatic amine skeleton. For example, indole derivatives, carbazole derivatives, triarylamine derivatives, and the like can be given. Examples of the nitrogen-containing five-membered heterocyclic skeleton include an imidazole skeleton, a triazole skeleton, and a tetrazole skeleton. As the organic compound 141_2, a material having a property of transporting more holes than electrons (a hole transporting material) can be used, and a material having a hole mobility of 1 × 10 ⁻⁶ cm ² / Vs or higher. It is preferable that The hole transporting material may be a polymer compound.

  As these materials having a high hole transporting property, specifically, as an aromatic amine compound, N, N′-di (p-tolyl) -N, N′-diphenyl-p-phenylenediamine (abbreviation: DTDPPA) 4,4′-bis [N- (4-diphenylaminophenyl) -N-phenylamino] biphenyl (abbreviation: DPAB), N, N′-bis {4- [bis (3-methylphenyl) amino] phenyl } -N, N′-diphenyl- (1,1′-biphenyl) -4,4′-diamine (abbreviation: DNTPD), 1,3,5-tris [N- (4-diphenylaminophenyl) -N— Phenylamino] benzene (abbreviation: DPA3B) and the like.

  As the carbazole derivative, specifically, 3- [N- (4-diphenylaminophenyl) -N-phenylamino] -9-phenylcarbazole (abbreviation: PCzDPA1), 3,6-bis [N- ( 4-diphenylaminophenyl) -N-phenylamino] -9-phenylcarbazole (abbreviation: PCzDPA2), 3,6-bis [N- (4-diphenylaminophenyl) -N- (1-naphthyl) amino] -9 -Phenylcarbazole (abbreviation: PCzTPN2), 3- [N- (9-phenylcarbazol-3-yl) -N-phenylamino] -9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis [N- ( 9-phenylcarbazol-3-yl) -N-phenylamino] -9-phenylcarbazole (abbreviation: PCzPCA2 , 3- [N- (1- naphthyl)-N-(9-phenyl-3-yl) amino] -9-phenylcarbazole (abbreviation: PCzPCN1), and the like.

  As other carbazole derivatives, 4,4′-di (N-carbazolyl) biphenyl (abbreviation: CBP), 1,3,5-tris [4- (N-carbazolyl) phenyl] benzene (abbreviation: TCPB) ), 9- [4- (10-phenyl-9-anthryl) phenyl] -9H-carbazole (abbreviation: CzPA), 1,4-bis [4- (N-carbazolyl) phenyl] -2,3,5, 6-tetraphenylbenzene or the like can be used.

  N, N-diphenyl-9- [4- (10-phenyl-9-anthryl) phenyl] -9H-carbazol-3-amine (abbreviation: CzA1PA), 4- (10-phenyl-9-anthryl) tri Phenylamine (abbreviation: DPhPA), 4- (9H-carbazol-9-yl) -4 '-(10-phenyl-9-anthryl) triphenylamine (abbreviation: YGAPA), N, 9-diphenyl-N- [ 4- (10-phenyl-9-anthryl) phenyl] -9H-carbazol-3-amine (abbreviation: PCAPA), N, 9-diphenyl-N- {4- [4- (10-phenyl-9-anthryl) Phenyl] phenyl} -9H-carbazol-3-amine (abbreviation: PCAPBA), N, 9-diphenyl-N- (9,10-diphenyl-2-anthri ) -9H-carbazol-3-amine (abbreviation: 2PCAPA), 9-phenyl-3- [4- (10-phenyl-9-anthryl) phenyl] -9H-carbazole (abbreviation: PCzPA), 3,6-diphenyl -9- [4- (10-phenyl-9-anthryl) phenyl] -9H-carbazole (abbreviation: DPCzPA), N, N, N ′, N ′, N ″, N ″, N ′ ″, N ′ ″-octaphenyldibenzo [g, p] chrysene-2,7,10,15-tetraamine (abbreviation: DBC1) or the like can be used.

  In addition, poly (N-vinylcarbazole) (abbreviation: PVK), poly (4-vinyltriphenylamine) (abbreviation: PVTPA), poly [N- (4- {N ′-[4- (4-diphenylamino)] Phenyl] phenyl-N′-phenylamino} phenyl) methacrylamide] (abbreviation: PTPDMA), poly [N, N′-bis (4-butylphenyl) -N, N′-bis (phenyl) benzidine] (abbreviation: Polymer compounds such as Poly-TPD can also be used.

  Further, as a material having a high hole transporting property, for example, 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: NPB or α-NPD), N, N′— Bis (3-methylphenyl) -N, N′-diphenyl- [1,1′-biphenyl] -4,4′-diamine (abbreviation: TPD), 4,4 ′, 4 ″ -tris (carbazole-9) -Yl) triphenylamine (abbreviation: TCTA), 4,4 ′, 4 ″ -tris [N- (1-naphthyl) -N-phenylamino] triphenylamine (abbreviation: 1′-TNATA), 4, 4 ′, 4 ″ -tris (N, N-diphenylamino) triphenylamine (abbreviation: TDATA), 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] Triphenylamine (abbreviation: M DATA), 4,4′-bis [N- (spiro-9,9′-bifluoren-2-yl) -N-phenylamino] biphenyl (abbreviation: BSPB), 4-phenyl-4 ′-(9-phenyl) Fluoren-9-yl) triphenylamine (abbreviation: BPAFLP), 4-phenyl-3 ′-(9-phenylfluoren-9-yl) triphenylamine (abbreviation: mBPAFLP), N- (9,9-dimethyl- 9H-Fluoren-2-yl) -N- {9,9-dimethyl-2- [N′-phenyl-N ′-(9,9-dimethyl-9H-fluoren-2-yl) amino] -9H-fluorene -7-yl} phenylamine (abbreviation: DFLADFL), N- (9,9-dimethyl-2-diphenylamino-9H-fluoren-7-yl) diphenylamine (abbreviation: DPNF) 2- [N- (4-diphenylaminophenyl) -N-phenylamino] spiro-9,9′-bifluorene (abbreviation: DPASF), 4-phenyl-4 ′-(9-phenyl-9H-carbazole-3) -Yl) triphenylamine (abbreviation: PCBA1BP), 4,4′-diphenyl-4 ″-(9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBBi1BP), 4- (1- Naphthyl) -4 ′-(9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBANB), 4,4′-di (1-naphthyl) -4 ″-(9-phenyl-9H -Carbazol-3-yl) triphenylamine (abbreviation: PCBNBB), 4-phenyldiphenyl- (9-phenyl-9H-carbazol-3-yl) ami (Abbreviation: PCA1BP), N, N′-bis (9-phenylcarbazol-3-yl) -N, N′-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N, N ′, N ″ -Triphenyl-N, N ', N' '-tris (9-phenylcarbazol-3-yl) benzene-1,3,5-triamine (abbreviation: PCA3B), N- (4-biphenyl) -N- ( 9,9-dimethyl-9H-fluoren-2-yl) -9-phenyl-9H-carbazol-3-amine (abbreviation: PCBiF), N- (1,1′-biphenyl-4-yl) -N- [ 4- (9-phenyl-9H-carbazol-3-yl) phenyl] -9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF), 9,9-dimethyl-N-phenyl-N- [ 4- (9- Enyl-9H-carbazol-3-yl) phenyl] fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N- [4- (9-phenyl-9H-carbazol-3-yl) phenyl] spiro-9 , 9′-bifluoren-2-amine (abbreviation: PCBASF), 2- [N- (9-phenylcarbazol-3-yl) -N-phenylamino] spiro-9,9′-bifluorene (abbreviation: PCASF), 2,7-bis [N- (4-diphenylaminophenyl) -N-phenylamino] -spiro-9,9'-bifluorene (abbreviation: DPA2SF), N- [4- (9H-carbazol-9-yl) Phenyl] -N- (4-phenyl) phenylaniline (abbreviation: YGA1BP), N, N′-bis [4- (carbazol-9-yl) phenyl] -N, N An aromatic amine compound such as' -diphenyl-9,9-dimethylfluorene-2,7-diamine (abbreviation: YGA2F) can be used. 3- [4- (1-naphthyl) -phenyl] -9-phenyl-9H-carbazole (abbreviation: PCPN), 3- [4- (9-phenanthryl) -phenyl] -9-phenyl-9H-carbazole (Abbreviation: PCPPn), 3,3′-bis (9-phenyl-9H-carbazole) (abbreviation: PCCP), 1,3-bis (N-carbazolyl) benzene (abbreviation: mCP), 3,6-bis ( 3,5-diphenylphenyl) -9-phenylcarbazole (abbreviation: CzTP), 3,6-di (9H-carbazol-9-yl) -9-phenyl-9H-carbazole (abbreviation: PhCzGI), 2,8- An amine compound such as di (9H-carbazol-9-yl) -dibenzothiophene (abbreviation: Cz2DBT), a carbazole compound, or the like can be used. Among the compounds described above, a compound having a pyrrole skeleton or an aromatic amine skeleton is preferable because it is stable and reliable. In addition, the compound having the skeleton has a high hole transport property and contributes to a reduction in driving voltage.

  As the organic compound 141_2, a compound having a nitrogen-containing five-membered heterocyclic skeleton such as an imidazole skeleton, a triazole skeleton, or a tetrazole skeleton can be used. Specifically, for example, 3- (4-biphenylyl) -4-phenyl-5- (4-tert-butylphenyl) -1,2,4-triazole (abbreviation: TAZ), 9- [4- (4 , 5-Diphenyl-4H-1,2,4-triazol-3-yl) phenyl] -9H-carbazole (abbreviation: CzTAZ1), 2,2 ′, 2 ″-(1,3,5-benzenetriyl ) Tris (1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2- [3- (dibenzothiophen-4-yl) phenyl] -1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), etc. Can be used.

  In the light-emitting layer 140, the guest material 142 is not particularly limited. Examples of the fluorescent compound include anthracene derivatives, tetracene derivatives, chrysene derivatives, phenanthrene derivatives, pyrene derivatives, perylene derivatives, stilbene derivatives, acridone derivatives, coumarins. Derivatives, phenoxazine derivatives, phenothiazine derivatives, and the like are preferable. For example, the following substances can be used. The organic compound according to one embodiment of the present invention can also be used because it can emit fluorescence.

  Specifically, 5,6-bis [4- (10-phenyl-9-anthryl) phenyl] -2,2′-bipyridine (abbreviation: PAP2BPy), 5,6-bis [4 ′-(10-phenyl) -9-anthryl) biphenyl-4-yl] -2,2'-bipyridine (abbreviation: PAPP2BPy), N, N'-diphenyl-N, N'-bis [4- (9-phenyl-9H-fluorene-9 -Yl) phenyl] pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N, N′-bis (3-methylphenyl) -N, N′-bis [3- (9-phenyl-9H-fluorene) -9-yl) phenyl] pyrene-1,6-diamine (abbreviation: 1,6 mM emFLPAPrn), N, N′-bis [4- (9-phenyl-9H-fluoren-9-yl) phenyl] -N, N '-Bis 4-tert-butylphenyl) -pyrene-1,6-diamine (abbreviation: 1,6tBu-FLPAPrn), N, N′-bis [4- (9-phenyl-9H-fluoren-9-yl) phenyl]- N, N′-diphenyl-3,8-dicyclohexylpyrene-1,6-diamine (abbreviation: ch-1,6FLPAPrn), N, N′-bis [4- (9H-carbazol-9-yl) phenyl]- N, N′-diphenylstilbene-4,4′-diamine (abbreviation: YGA2S), 4- (9H-carbazol-9-yl) -4 ′-(10-phenyl-9-anthryl) triphenylamine (abbreviation: YGAPA), 4- (9H-carbazol-9-yl) -4 ′-(9,10-diphenyl-2-anthryl) triphenylamine (abbreviation: 2YGAPPA), N 9-diphenyl-N- [4- (10-phenyl-9-anthryl) phenyl] -9H-carbazol-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra (tert-butyl) Perylene (abbreviation: TBP), 4- (10-phenyl-9-anthryl) -4 ′-(9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBAPA), N, N ″ — (2-tert-butylanthracene-9,10-diyldi-4,1-phenylene) bis [N, N ′, N′-triphenyl-1,4-phenylenediamine] (abbreviation: DPABPA), N, 9- Diphenyl-N- [4- (9,10-diphenyl-2-anthryl) phenyl] -9H-carbazol-3-amine (abbreviation: 2PCAPPA), N- [4- (9 , 10-diphenyl-2-anthryl) phenyl] -N, N ′, N′-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N, N, N ′, N ′, N ″, N '', N '' ', N' ''-octaphenyldibenzo [g, p] chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), coumarin 30, N- (9,10-diphenyl- 2-anthryl) -N, 9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA), N- [9,10-bis (1,1′-biphenyl-2-yl) -2-anthryl]- N, 9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPhA), N- (9,10-diphenyl-2-anthryl) -N, N ′, N′-triphenyl-1,4-phenylenedi Ami (Abbreviation: 2DPAPA), N- [9,10-bis (1,1′-biphenyl-2-yl) -2-anthryl] -N, N ′, N′-triphenyl-1,4-phenylenediamine ( Abbreviation: 2DPABPhA), 9,10-bis (1,1′-biphenyl-2-yl) -N- [4- (9H-carbazol-9-yl) phenyl] -N-phenylanthracen-2-amine (abbreviation) : 2YGABPhA), N, N, 9-triphenylanthracen-9-amine (abbreviation: DPhAPhA), coumarin 6, coumarin 545T, N, N′-diphenylquinacridone (abbreviation: DPQd), rubrene, 2,8-di- tert-Butyl-5,11-bis (4-tert-butylphenyl) -6,12-diphenyltetracene (abbreviation: TBRb), Nile Red, 5,1 -Bis (1,1′-biphenyl-4-yl) -6,11-diphenyltetracene (abbreviation: BPT), 2- (2- {2- [4- (dimethylamino) phenyl] ethenyl} -6-methyl -4H-pyran-4-ylidene) propanedinitrile (abbreviation: DCM1), 2- {2-methyl-6- [2- (2,3,6,7-tetrahydro-1H, 5H-benzo [ij] quinolidine -9-yl) ethenyl] -4H-pyran-4-ylidene} propanedinitrile (abbreviation: DCM2), N, N, N ′, N′-tetrakis (4-methylphenyl) tetracene-5,11-diamine ( Abbreviation: p-mPhTD), 7,14-diphenyl-N, N, N ′, N′-tetrakis (4-methylphenyl) acenaphtho [1,2-a] fluoranthene-3,10-diamine (abbreviation: p -MPhAFD), 2- {2-isopropyl-6- [2- (1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H, 5H-benzo [ij] quinolidine-9- Yl) ethenyl] -4H-pyran-4-ylidene} propanedinitrile (abbreviation: DCJTI), 2- {2-tert-butyl-6- [2- (1,1,7,7-tetramethyl-2, 3,6,7-tetrahydro-1H, 5H-benzo [ij] quinolizin-9-yl) ethenyl] -4H-pyran-4-ylidene} propanedinitrile (abbreviation: DCJTB), 2- (2,6-bis {2- [4- (dimethylamino) phenyl] ethenyl} -4H-pyran-4-ylidene) propanedinitrile (abbreviation: BisDCM), 2- {2,6-bis [2- (8-methoxy-1, 1,7,7- Tramethyl-2,3,6,7-tetrahydro-1H, 5H-benzo [ij] quinolizin-9-yl) ethenyl] -4H-pyran-4-ylidene} propanedinitrile (abbreviation: BisDCJTM), 5,10, 15,20-tetraphenylbisbenzo [5,6] indeno [1,2,3-cd: 1 ′, 2 ′, 3′-lm] perylene, and the like.

  Examples of the guest material 142 (phosphorescent compound) include iridium, rhodium, or platinum-based organometallic complexes, or metal complexes. Among these, organic iridium complexes such as iridium-based orthometal complexes are preferable. Examples of orthometalated ligands include 4H-triazole ligands, 1H-triazole ligands, imidazole ligands, pyridine ligands, pyrimidine ligands, pyrazine ligands, and isoquinoline ligands. Can be mentioned. Examples of the metal complex include a platinum complex having a porphyrin ligand.

As a substance having an emission peak in blue or green, for example, tris {2- [5- (2-methylphenyl) -4- (2,6-dimethylphenyl) -4H-1,2,4-triazole-3 -Yl- [kappa] N2] phenyl- [kappa] C} iridium (III) (abbreviation: Ir (mppptz-dmp) ₃ ), tris (5-methyl-3,4-diphenyl-4H-1,2,4-triazolate) iridium (III ) (Abbreviation: Ir (Mptz) ₃ ), tris [4- (3-biphenyl) -5-isopropyl-3-phenyl-4H-1,2,4-triazolato] iridium (III) (abbreviation: Ir (iPrptz- 3b) ₃ ), tris [3- (5-biphenyl) -5-isopropyl-4-phenyl-4H-1,2,4-triazolato] iridium (III) (abbreviation: Ir (IPr5btz) ₃ ), an organometallic iridium complex having a 4H-triazole skeleton, or tris [3-methyl-1- (2-methylphenyl) -5-phenyl-1H-1,2,4-triazolate] Iridium (III) (abbreviation: Ir (Mptz1-mp) ₃ ), tris (1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato) iridium (III) (abbreviation: Ir (Prptz1) -Me) ₃ ) an organometallic iridium complex having a 1H-triazole skeleton, fac-tris [1- (2,6-diisopropylphenyl) -2-phenyl-1H-imidazole] iridium (III) (abbreviation: Ir _{(iPrpmi) 3),} tris [3- (2,6-dimethylphenyl) -7-methylimidazo [1, 2-f] Enantorijinato] iridium (III) _{(abbreviation: Ir (dmpimpt-Me) 3} ) or an organic iridium complex having an imidazole skeleton, such as bis [2- (4 ', 6'-difluorophenyl) pyridinato -N, ^{C 2 '} ] Iridium (III) tetrakis (1-pyrazolyl) borate (abbreviation: FIr6), bis [2- (4 ′, 6′-difluorophenyl) pyridinato-N, C ^{2 ′} ] iridium (III) picolinate (abbreviation: FIrpic) ), Bis {2- [3 ′, 5′-bis (trifluoromethyl) phenyl] pyridinato-N, C ^{2 ′} } iridium (III) picolinate (abbreviation: Ir (CF ₃ ppy) ₂ (pic)), bis [2- (4 ', 6'-difluorophenyl) pyridinato -N, C ^2'] iridium (III) acetylacetonate Abbreviation: FIr (acac)) organometallic iridium complex having a ligand of phenylpyridine derivative having an electron-withdrawing group such as and the like. Among the above-mentioned, organometallic iridium complexes having a nitrogen-containing five-membered heterocyclic skeleton such as a 4H-triazole skeleton, a 1H-triazole skeleton, and an imidazole skeleton have high triplet excitation energy, and have high reliability and luminous efficiency. It is particularly preferred because of its superiority.

Examples of a substance having an emission peak in green or yellow include tris (4-methyl-6-phenylpyrimidinato) iridium (III) (abbreviation: Ir (mppm) ₃ ), tris (4-t-butyl). -6-phenylpyrimidinato) iridium (III) (abbreviation: Ir (tBupppm) ₃ ), (acetylacetonato) bis (6-methyl-4-phenylpyrimidinato) iridium (III) (abbreviation: Ir (mppm) ) ₂ (acac)), (acetylacetonato) bis (6-tert-butyl-4-phenylpyrimidinato) iridium (III) (abbreviation: Ir (tBupppm) ₂ (acac)), (acetylacetonato) bis [4- (2-norbornyl) -6-phenylpyrimidinato] iridium (III) (abbreviation: Ir (nbppm) ₂ (Acac)), (acetylacetonato) bis [5-methyl-6- (2-methylphenyl) -4-phenylpyrimidinato] iridium (III) (abbreviation: Ir (mpmppm) ₂ (acac)), ( Acetylacetonato) bis {4,6-dimethyl-2- [6- (2,6-dimethylphenyl) -4-pyrimidinyl-κN3] phenyl-κC} iridium (III) (abbreviation: Ir (dmppm-dmp) ₂ (Acac)), (acetylacetonato) bis (4,6-diphenylpyrimidinato) iridium (III) (abbreviation: Ir (dppm) ₂ (acac)), an organometallic iridium complex having a pyrimidine skeleton, (Acetylacetonato) bis (3,5-dimethyl-2-phenylpyrazinato) iridium (III) (abbreviation: Ir (mppr -Me) ₂ (acac)), (acetylacetonato) bis (5-isopropyl-3-methyl-2-phenylpyrazinato) iridium (III) (abbreviation: Ir (mppr-iPr) ₂ (acac)) Organometallic iridium complexes having such a pyrazine skeleton, tris (2-phenylpyridinato-N, C ^{2 ′} ) iridium (III) (abbreviation: Ir (ppy) ₃ ), bis (2-phenylpyridinato- N, C ^{2 ′} ) iridium (III) acetylacetonate (abbreviation: Ir (ppy) ₂ (acac)), bis (benzo [h] quinolinato) iridium (III) acetylacetonate (abbreviation: Ir (bzq) ₂ ( acac)), tris (benzo [h] quinolinato) iridium (III) (abbreviation: Ir _(bzq) 3), tris (2-Fenirukino Isocyanato -N, C ^{2 ')} iridium (III) (abbreviation: Ir _(pq) 3), bis (2-phenylquinolinato--N, C ^2') iridium (III) acetylacetonate (abbreviation: Ir (pq) ₂ (acac)), an organometallic iridium complex having a pyridine skeleton, or bis (2,4-diphenyl-1,3-oxazolate-N, C ^{2 ′} ) iridium (III) acetylacetonate (abbreviation: Ir ( dpo) ₂ (acac)), bis {2- [4 ′-(perfluorophenyl) phenyl] pyridinato-N, C ^{2 ′} } iridium (III) acetylacetonate (abbreviation: Ir (p-PF-ph) ₂ (Acac)), bis (2-phenylbenzothiazolate-N, C ^{2 ′} ) iridium (III) acetylacetonate (abbreviation: Ir (bt) ₂ (acac )) And other rare earth metal complexes such as tris (acetylacetonato) (monophenanthroline) terbium (III) (abbreviation: Tb (acac) ₃ (Phen)). Among the above-described compounds, organometallic iridium complexes having a pyrimidine skeleton are particularly preferable because they are remarkably excellent in reliability and luminous efficiency.

As a substance having an emission peak in yellow or red, for example, (diisobutyrylmethanato) bis [4,6-bis (3-methylphenyl) pyrimidinato] iridium (III) (abbreviation: Ir (5 mdppm) ₂ ( dibm)), bis [4,6-bis (3-methylphenyl) pyrimidinato] (dipivaloylmethanato) iridium (III) (abbreviation: Ir (5 mdppm) ₂ (dpm)), bis [4,6-di (Naphthalen-1-yl) pyrimidinato] (dipivaloylmethanato) iridium (III) (abbreviation: Ir (d1npm) ₂ (dpm)), an organometallic iridium complex having a pyrimidine skeleton, and (acetylacetonato) bis (2,3,5-triphenylpyrazinato) iridium (III) (abbreviation: Ir _(tppr) 2 (ac c)), bis (2,3,5-triphenylpyrazinato) (dipivaloylmethanato) iridium (III) (abbreviation: Ir _(tppr) 2 (dpm)), (acetylacetonato) bis [2 , 3-bis (4-fluorophenyl) quinoxalinato] iridium (III) (abbreviation: Ir (Fdpq) ₂ (acac)), organometallic iridium complexes having a pyrazine skeleton, tris (1-phenylisoquinolinato- N, C ^{2 ′} ) iridium (III) (abbreviation: Ir (piq) ₃ ), bis (1-phenylisoquinolinato-N, C ^{2 ′} ) iridium (III) acetylacetonate (abbreviation: Ir (piq) ₂ In addition to organometallic iridium complexes having a pyridine skeleton such as (acac)), 2,3,7,8,12,1417,18-octaethyl-21 , 23H-porphyrin platinum (II) (abbreviation: PtOEP), tris (1,3-diphenyl-1,3-propanedionato) (monophenanthroline) europium (III) (abbreviation: Eu (DBM) ₃ (Phen)), tris [1- (2-thenoyl) -3,3,3-trifluoroacetonato] (monophenanthroline) europium (III) (abbreviation: Eu (TTA) ₃ (Phen)) Rare earth metal complexes. Among the above-described compounds, organometallic iridium complexes having a pyrimidine skeleton are particularly preferable because they are remarkably excellent in reliability and luminous efficiency. An organometallic iridium complex having a pyrazine skeleton can emit red light with good chromaticity.

  The light-emitting material contained in the light-emitting layer 140 is preferably a material that can convert triplet excitation energy into light emission. Examples of the material capable of converting the triplet excitation energy into light emission include a thermally activated delayed fluorescence (TADF) material in addition to a phosphorescent compound. Therefore, the portion described as a phosphorescent compound may be read as a thermally activated delayed fluorescent material. Note that the thermally activated delayed fluorescent material has a small difference between the triplet excitation energy level and the singlet excitation energy level, and the function of converting energy from the triplet excited state to the singlet excited state by crossing between inverses. It is the material which has. Therefore, the triplet excited state can be up-converted (reverse intersystem crossing) into a singlet excited state with a slight thermal energy, and light emission (fluorescence) from the singlet excited state can be efficiently exhibited. As a condition for efficiently obtaining thermally activated delayed fluorescence, the energy difference between the triplet excitation energy level and the singlet excitation energy level is preferably greater than 0 eV but not greater than 0.2 eV, more preferably greater than 0 eV and not greater than 0. 0.1 eV or less.

  When the thermally activated delayed fluorescent material is composed of one type of material, for example, the following materials can be used.

First, fullerene and its derivatives, acridine derivatives such as proflavine, eosin and the like can be mentioned. In addition, metal-containing porphyrins including magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), palladium (Pd), and the like can be given. Examples of the metal-containing porphyrin include a protoporphyrin-tin fluoride complex (SnF ₂ (Proto IX)), a mesoporphyrin-tin fluoride complex (SnF ₂ (Meso IX)), and a hematoporphyrin-tin fluoride complex (SnF). ₂ (Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (SnF ₂ (Copro III-4Me)), octaethylporphyrin-tin fluoride complex (SnF ₂ (OEP)), etioporphyrin-tin fluoride And a complex (SnF ₂ (Etio I)), octaethylporphyrin-platinum chloride complex (PtCl ₂ OEP), and the like.

  In addition, as the thermally activated delayed fluorescent material composed of a kind of material, a heterocyclic compound having a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring can also be used. Specifically, 2- (biphenyl-4-yl) -4,6-bis (12-phenylindolo [2,3-a] carbazol-11-yl) -1,3,5-triazine (abbreviation: PIC-TRZ), 2- {4- [3- (N-phenyl-9H-carbazol-3-yl) -9H-carbazol-9-yl] phenyl} -4,6-diphenyl-1,3,5- Triazine (abbreviation: PCCzPTzn), 2- [4- (10H-phenoxazin-10-yl) phenyl] -4,6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3- [4 -(5-phenyl-5,10-dihydrophenazin-10-yl) phenyl] -4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3- (9,9-dimethyl- 9H-acridine- 0-yl) -9H-xanthen-9-one (abbreviation: ACRXTN), bis [4- (9,9-dimethyl-9,10-dihydroacridine) phenyl] sulfone (abbreviation: DMAC-DPS), 10-phenyl -10H, 10'H-spiro [acridine-9,9'-anthracene] -10'-one (abbreviation: ACRSA) and the like. Since the heterocyclic compound has a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring, it is preferable because of its high electron transporting property and hole transporting property. Among these, among skeletons having a π-electron deficient heteroaromatic ring, a diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton) or a triazine skeleton is preferable because it is stable and has high reliability. Among skeletons having a π-electron rich heteroaromatic ring, an acridine skeleton, a phenoxazine skeleton, a thiophene skeleton, a furan skeleton, and a pyrrole skeleton are stable and reliable. It is preferable to have one or more. As the pyrrole skeleton, an indole skeleton, a carbazole skeleton, and a 3- (9-phenyl-9H-carbazol-3-yl) -9H-carbazole skeleton are particularly preferable. A substance in which a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring are directly bonded has both a donor property of a π-electron rich heteroaromatic ring and an acceptor property of a π-electron deficient heteroaromatic ring, This is particularly preferable because the difference between the energy level in the singlet excited state and the energy level in the triplet excited state is small.

  Further, the light-emitting layer 140 may include a material other than the host material 141 and the guest material 142.

  A material that can be used for the light-emitting layer 140 is not particularly limited, and examples thereof include condensed polycyclic aromatic compounds such as anthracene derivatives, phenanthrene derivatives, pyrene derivatives, chrysene derivatives, and dibenzo [g, p] chrysene derivatives. Specifically, 9,10-diphenylanthracene (abbreviation: DPAnth), 6,12-dimethoxy-5,11-diphenylchrysene, 9,10-bis (3,5-diphenylphenyl) anthracene (abbreviation: DPPA), 9,10-di (2-naphthyl) anthracene (abbreviation: DNA), 2-tert-butyl-9,10-di (2-naphthyl) anthracene (abbreviation: t-BuDNA), 9,9′- Bianthryl (abbreviation: BANT), 9,9 ′-(stilbene-3,3′-diyl) diphenanthrene (abbreviation: DP) S), 9,9 ′-(stilbene-4,4′-diyl) diphenanthrene (abbreviation: DPNS2), 1,3,5-tri (1-pyrenyl) benzene (abbreviation: TPB3), and the like. . One or more kinds of substances having a singlet excitation energy level or a triplet excitation energy level higher than the excitation energy level of the guest material 142 may be selected from these and known substances. .

  For example, a compound having a heteroaromatic skeleton such as an oxadiazole derivative can be used for the light-emitting layer 140. Specifically, for example, 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis [5- (P-tert-butylphenyl) -1,3,4-oxadiazol-2-yl] benzene (abbreviation: OXD-7), 9- [4- (5-phenyl-1,3,4-oxadi) Heterocyclic compounds such as (azol-2-yl) phenyl] -9H-carbazole (abbreviation: CO11) and 4,4′-bis (5-methylbenzoxazol-2-yl) stilbene (abbreviation: BzOs).

In addition, a metal complex having a heterocyclic ring (eg, zinc and aluminum-based metal complex) or the like can be used for the light-emitting layer 140. For example, a metal complex having a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand can be given. Specifically, for example, tris (8-quinolinolato) aluminum (III) (abbreviation: Alq), tris (4-methyl-8-quinolinolato) aluminum (III) (abbreviation: Almq ₃ ), bis (10-hydroxybenzo) [H] quinolinato) beryllium (II) (abbreviation: BeBq ₂ ), bis (2-methyl-8-quinolinolato) (4-phenylphenolato) aluminum (III) (abbreviation: BAlq), bis (8-quinolinolato) zinc (II) (abbreviation: Znq) and the like include metal complexes having a quinoline skeleton or a benzoquinoline skeleton. In addition, bis [2- (2-benzoxazolyl) phenolato] zinc (II) (abbreviation: ZnPBO), bis [2- (2-benzothiazolyl) phenolato] zinc (II) (abbreviation: ZnBTZ), etc. A metal complex having an oxazole-based or thiazole-based ligand can also be used.

  Note that the light emitting layer 140 may be formed of a plurality of layers of two or more layers. For example, when the first light-emitting layer and the second light-emitting layer are sequentially stacked from the hole transport layer side to form the light-emitting layer 140, a substance having a hole-transport property is used as the host material of the first light-emitting layer There is a structure in which a substance having an electron transporting property is used as a host material of the second light emitting layer. In addition, the light-emitting materials included in the first light-emitting layer and the second light-emitting layer may be the same material or different materials, and may be different materials that have a function of emitting light of the same color. A material having a function of emitting light of a color may be used. By using a light emitting material having a function of emitting light of different colors for each of the two light emitting layers, a plurality of light emissions can be obtained simultaneously. In particular, it is preferable to select a light emitting material used for each light emitting layer so that the light emitted by the two light emitting layers is white.

  Note that the light-emitting layer 140 can be formed by a method such as a vapor deposition method (including a vacuum vapor deposition method), an inkjet method, a coating method, or gravure printing. Further, in addition to the materials described above, an inorganic compound such as a quantum dot or a polymer compound (oligomer, dendrimer, polymer, etc.) may be included.

≪Hole injection layer≫
The hole injection layer 111 has a function of promoting hole injection by reducing a hole injection barrier from one of the pair of electrodes (the electrode 101 or the electrode 102). For example, a transition metal oxide, a phthalocyanine derivative, or an aromatic Formed by a group amine. Examples of the transition metal oxide include molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide. Examples of the phthalocyanine derivative include phthalocyanine and metal phthalocyanine. Examples of aromatic amines include benzidine derivatives and phenylenediamine derivatives. High molecular compounds such as polythiophene and polyaniline can also be used. For example, self-doped polythiophene poly (ethylenedioxythiophene) / poly (styrenesulfonic acid) is a typical example.

As the hole-injecting layer 111, a layer including a composite material of a hole-transporting material and a material that exhibits an electron-accepting property can be used. Alternatively, a stack of a layer containing a material showing an electron accepting property and a layer containing a hole transporting material may be used. Charges can be transferred between these materials in a steady state or in the presence of an electric field. Examples of the material exhibiting electron acceptability include organic acceptors such as quinodimethane derivatives, chloranil derivatives, and hexaazatriphenylene derivatives. Specifically, 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F ₄ -TCNQ), chloranil, 2,3,6,7,10,11 -A compound having an electron withdrawing group (halogen group or cyano group) such as hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN). Transition metal oxides such as Group 4 to Group 8 metal oxides can also be used. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, rhenium oxide, and the like. Among these, molybdenum oxide is preferable because it is stable in the air, has a low hygroscopic property, and is easy to handle.

As the hole transporting material, a material having a hole transporting property higher than that of electrons can be used, and a material having a hole mobility of 1 × 10 ⁻⁶ cm ² / Vs or more is preferable. Specifically, aromatic amines, carbazole derivatives, aromatic hydrocarbons, stilbene derivatives, and the like which are listed as hole transporting materials that can be used for the light-emitting layer 140 can be used. The hole transporting material may be a polymer compound.

Other examples of the hole transporting material include aromatic hydrocarbons, such as 2-tert-butyl-9,10-di (2-naphthyl) anthracene (abbreviation: t-BuDNA), 2-tert- Butyl-9,10-di (1-naphthyl) anthracene, 9,10-bis (3,5-diphenylphenyl) anthracene (abbreviation: DPPA), 2-tert-butyl-9,10-bis (4-phenylphenyl) ) Anthracene (abbreviation: t-BuDBA), 9,10-di (2-naphthyl) anthracene (abbreviation: DNA), 9,10-diphenylanthracene (abbreviation: DPAnth), 2-tert-butylanthracene (abbreviation: t-) BuAnth), 9,10-bis (4-methyl-1-naphthyl) anthracene (abbreviation: DMNA), 2-tert-butyl-9, 0-bis [2- (1-naphthyl) phenyl] anthracene, 9,10-bis [2- (1-naphthyl) phenyl] anthracene, 2,3,6,7-tetramethyl-9,10-di (1 -Naphthyl) anthracene, 2,3,6,7-tetramethyl-9,10-di (2-naphthyl) anthracene, 9,9'-bianthryl, 10,10'-diphenyl-9,9'-bianthryl, 10 , 10′-bis (2-phenylphenyl) -9,9′-bianthryl, 10,10′-bis [(2,3,4,5,6-pentaphenyl) phenyl] -9,9′-bianthryl, Anthracene, tetracene, rubrene, perylene, 2,5,8,11-tetra (tert-butyl) perylene and the like can be mentioned. In addition, pentacene, coronene, and the like can also be used. Thus, it is more preferable to use an aromatic hydrocarbon having a hole mobility of 1 × 10 ⁻⁶ cm ² / Vs or more and having 14 to 42 carbon atoms.

  The aromatic hydrocarbon may have a vinyl skeleton. As the aromatic hydrocarbon having a vinyl group, for example, 4,4′-bis (2,2-diphenylvinyl) biphenyl (abbreviation: DPVBi), 9,10-bis [4- (2,2- Diphenylvinyl) phenyl] anthracene (abbreviation: DPVPA) and the like.

  4- {3- [3- (9-phenyl-9H-fluoren-9-yl) phenyl] phenyl} dibenzofuran (abbreviation: mmDBFFLBi-II), 4,4 ′, 4 ″-(benzene-1, 3,5-triyl) tri (dibenzofuran) (abbreviation: DBF3P-II), 1,3,5-tri (dibenzothiophen-4-yl) -benzene (abbreviation: DBT3P-II), 2,8-diphenyl-4 -[4- (9-phenyl-9H-fluoren-9-yl) phenyl] dibenzothiophene (abbreviation: DBTFLP-III), 4- [4- (9-phenyl-9H-fluoren-9-yl) phenyl]- 6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), 4- [3- (triphenylene-2-yl) phenyl] dibenzothiophene (abbreviation: mDBT) Tp-II) thiophene compounds, such as, furan compounds, fluorene compounds, triphenylene compounds, can be used phenanthrene compounds. Among the compounds described above, a compound having a pyrrole skeleton, a furan skeleton, a thiophene skeleton, or an aromatic amine skeleton is preferable because it is stable and reliable. In addition, the compound having the skeleton has a high hole transport property and contributes to a reduction in driving voltage.

≪Hole transport layer≫
The hole transport layer 112 is a layer containing a hole transport material, and the hole transport material exemplified as the material of the hole injection layer 111 can be used. Since the hole transport layer 112 has a function of transporting holes injected into the hole injection layer 111 to the light emitting layer 140, a HOMO (High Occupied Molecular Orbital, also called the highest occupied orbit) quasi of the hole injection layer 111 is provided. It is preferable to have a HOMO level that is the same as or close to the position.

In addition, a substance having a hole mobility of 1 × 10 ⁻⁶ cm ² / Vs or higher is preferable. However, any substance other than these may be used as long as it has a property of transporting more holes than electrons. Note that the layer containing a substance having a high hole-transport property is not limited to a single layer, and two or more layers containing the above substances may be stacked.

≪Electron transport layer≫
The electron transport layer 118 has a function of transporting electrons injected from the other of the pair of electrodes (the electrode 101 or the electrode 102) through the electron injection layer 119 to the light emitting layer 140. As the electron transporting material, a material having a higher electron transporting property than holes can be used, and a material having an electron mobility of 1 × 10 ⁻⁶ cm ² / Vs or more is preferable. In particular, the organic compound according to one embodiment of the present invention can be preferably used. As a compound that easily receives electrons (a material having an electron transporting property), a π-electron deficient heteroaromatic such as a nitrogen-containing heteroaromatic compound, a metal complex, or the like can be used. Specifically, the pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, triazine derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, phenanthroline derivatives, triazole derivatives, benzimidazole derivatives, oxalates, which are listed as electron transporting materials that can be used for the light emitting layer 140. And diazole derivatives. Further, a substance having an electron mobility of 1 × 10 ⁻⁶ cm ² / Vs or higher is preferable. Note that other than the above substances, any substance that has a property of transporting more electrons than holes may be used for the electron-transport layer. Further, the electron-transporting layer 118 is not limited to a single layer, and two or more layers including the above substances may be stacked.

Moreover, the metal complex which has a heterocyclic ring is mentioned, For example, the metal complex which has a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand is mentioned. Specifically, for example, tris (8-quinolinolato) aluminum (III) (abbreviation: Alq), tris (4-methyl-8-quinolinolato) aluminum (III) (abbreviation: Almq ₃ ), bis (10-hydroxybenzo) [H] quinolinato) beryllium (II) (abbreviation: BeBq ₂ ), bis (2-methyl-8-quinolinolato) (4-phenylphenolato) aluminum (III) (abbreviation: BAlq), bis (8-quinolinolato) zinc (II) (abbreviation: Znq) and the like include metal complexes having a quinoline skeleton or a benzoquinoline skeleton. In addition, bis [2- (2-benzoxazolyl) phenolato] zinc (II) (abbreviation: ZnPBO), bis [2- (2-benzothiazolyl) phenolato] zinc (II) (abbreviation: ZnBTZ), etc. A metal complex having an oxazole-based or thiazole-based ligand can also be used.

  Further, a layer for controlling the movement of electron carriers may be provided between the electron transport layer 118 and the light emitting layer 140. This is a layer obtained by adding a small amount of a substance having a high electron trapping property to a material having a high electron transporting property as described above. By suppressing the movement of electron carriers, the carrier balance can be adjusted. Such a configuration is highly effective in suppressing problems that occur when the electron transporting property of the electron transporting material is significantly higher than the hole transporting property of the hole transporting material (for example, a reduction in device lifetime). .

≪Electron injection layer≫
The electron injection layer 119 has a function of promoting electron injection by reducing an electron injection barrier from the electrode 102. For example, a Group 1 metal, a Group 2 metal, or an oxide, halide, carbonate, or the like thereof is used. Can be used. Alternatively, a composite material of the electron transporting material described above and a material exhibiting an electron donating property can be used. Examples of the material exhibiting electron donating properties include Group 1 metals, Group 2 metals, and oxides thereof. Specifically, alkali metals such as lithium fluoride (LiF), sodium fluoride (NaF), cesium fluoride (CsF), calcium fluoride (CaF ₂ ), lithium oxide (LiO _x ), etc., alkaline earth Similar metals, or compounds thereof can be used. Alternatively, a rare earth metal compound such as erbium fluoride (ErF ₃ ) can be used. Further, electride may be used for the electron injection layer 119. Examples of the electride include a substance obtained by adding a high concentration of electrons to a mixed oxide of calcium and aluminum. Alternatively, a substance that can be used for the electron-transport layer 118 may be used for the electron-injection layer 119.

  Alternatively, a composite material obtained by mixing an organic compound and an electron donor (donor) may be used for the electron injection layer 119. Such a composite material is excellent in electron injecting property and electron transporting property because electrons are generated in the organic compound by the electron donor. In this case, the organic compound is preferably a material excellent in transporting the generated electrons. Specifically, for example, a substance (metal complex, heteroaromatic compound, or the like) constituting the electron transport layer 118 described above is used. Can be used. The electron donor may be any substance that exhibits an electron donating property to the organic compound. Specifically, an alkali metal, an alkaline earth metal, or a rare earth metal is preferable, and examples thereof include lithium, sodium, cesium, magnesium, calcium, erbium, and ytterbium. Alkali metal oxides and alkaline earth metal oxides are preferable, and lithium oxide, calcium oxide, barium oxide, and the like can be given. A Lewis base such as magnesium oxide can also be used. Alternatively, an organic compound such as tetrathiafulvalene (abbreviation: TTF) can be used.

  Note that the light emitting layer, the hole injection layer, the hole transport layer, the electron transport layer, and the electron injection layer described above are formed by a vapor deposition method (including a vacuum vapor deposition method), an inkjet method, a coating method, a gravure printing, and the like, respectively. Can be formed by a method. In addition to the above materials, the light emitting layer, hole injection layer, hole transport layer, electron transport layer, and electron injection layer described above include inorganic compounds such as quantum dots, and polymer compounds (oligomers, dendrimers). , Polymers, etc.) may be used.

≪Quantum dots≫
A quantum dot is a semiconductor nanocrystal having a size of several nanometers to several tens of nanometers, and is composed of about 1 × 10 ³ to 1 × 10 ⁶ atoms. Since quantum dots shift in energy depending on the size, even if the quantum dots are made of the same material, the emission wavelength differs depending on the size. Therefore, the emission wavelength can be easily changed by changing the size of the quantum dots to be used.

  In addition, since the quantum dot has a narrow emission spectrum peak width, light emission with good color purity can be obtained. Furthermore, the theoretical internal quantum efficiency of quantum dots is said to be almost 100%, which is much higher than 25% of organic compounds that exhibit fluorescence and is equivalent to organic compounds that exhibit phosphorescence. For this reason, a light-emitting element with high emission efficiency can be obtained by using quantum dots as a light-emitting material. In addition, quantum dots, which are inorganic materials, are excellent in essential stability, and thus a light-emitting element that is preferable from the viewpoint of life can be obtained.

  The materials constituting the quantum dots include group 14 elements, group 15 elements, group 16 elements, compounds composed of a plurality of group 14 elements, elements belonging to groups 4 to 14 and group 16 elements. Compounds of Group 2, elements of Group 16 and Group 16, compounds of Group 13 elements and Group 15 elements, compounds of Group 13 elements and Group 17 elements, Group 14 elements and Group 15 Examples thereof include compounds with elements, compounds of Group 11 elements and Group 17 elements, iron oxides, titanium oxides, chalcogenide spinels, and semiconductor clusters.

  Specifically, cadmium selenide, cadmium sulfide, cadmium telluride, zinc selenide, zinc oxide, zinc sulfide, zinc telluride, mercury sulfide, mercury selenide, mercury telluride, indium arsenide, indium phosphide, gallium arsenide , Gallium phosphide, indium nitride, gallium nitride, indium antimonide, gallium phosphide, aluminum arsenide, aluminum arsenide, aluminum antimonide, lead selenide, lead telluride, lead sulfide, indium selenide, indium telluride, sulfide Indium, gallium selenide, arsenic sulfide, arsenic selenide, arsenic telluride, antimony sulfide, antimony selenide, antimony telluride, bismuth sulfide, bismuth selenide, bismuth telluride, silicon, silicon carbide, germanium, tin, selenium, Tellurium, Hou , Carbon, phosphorus, boron nitride, boron phosphide, boron arsenide, aluminum nitride, aluminum sulfide, barium sulfide, barium selenide, barium telluride, calcium sulfide, calcium selenide, calcium telluride, beryllium sulfide, beryllium selenide, Beryllium telluride, magnesium sulfide, magnesium selenide, germanium sulfide, germanium selenide, germanium telluride, tin sulfide, tin selenide, tin telluride, lead oxide, copper fluoride, copper chloride, copper bromide, copper iodide , Copper oxide, copper selenide, nickel oxide, cobalt oxide, cobalt sulfide, iron oxide, iron sulfide, manganese oxide, molybdenum sulfide, vanadium oxide, vanadium oxide, tungsten oxide, tantalum oxide, titanium oxide, zirconium oxide, silicon nitride, Germanium nitride, oxidation Luminium, barium titanate, selenium, zinc and cadmium compound, indium, arsenic and phosphorus compound, cadmium, selenium and sulfur compound, cadmium, selenium and tellurium compound, indium, gallium and arsenic compound, indium and gallium and Examples include, but are not limited to, compounds of selenium, compounds of indium, selenium and sulfur, compounds of copper, indium and sulfur, and combinations thereof. Moreover, you may use what is called an alloy type quantum dot whose composition is represented by arbitrary ratios. For example, an alloy type quantum dot of cadmium, selenium, and sulfur is one of effective means for obtaining blue light emission because the emission wavelength can be changed by changing the content ratio of elements.

  The structure of the quantum dot includes a core type, a core-shell type, and a core-multishell type, and any of them may be used, but the shell is covered with another inorganic material that covers the core and has a wider band gap. By forming, the influence of defects and dangling bonds existing on the nanocrystal surface can be reduced. Thereby, in order to greatly improve the quantum efficiency of light emission, it is preferable to use a core-shell type or core-multishell type quantum dot. Examples of the shell material include zinc sulfide and zinc oxide.

  In addition, since the quantum dots have a high ratio of surface atoms, they are highly reactive and tend to aggregate. Therefore, it is preferable that a protective agent is attached or a protective group is provided on the surface of the quantum dots. Aggregation can be prevented and solubility in a solvent can be increased by attaching the protective agent or providing a protective group. It is also possible to reduce the reactivity and improve the electrical stability. Examples of the protecting agent (or protecting group) include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, tripropylphosphine, tributylphosphine, trihexylphosphine, Trialkylphosphines such as octylphosphine, polyoxyethylene alkylphenyl ethers such as polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, tri (n-hexyl) amine, tri (n-octyl) Tertiary amines such as amine and tri (n-decyl) amine, tripropylphosphine oxide, tributylphosphine oxide, trihexylphosphine oxide, trioctylphosphite Organic phosphorus compounds such as oxides and tridecylphosphine oxides, polyethylene glycol diesters such as polyethylene glycol dilaurate and polyethylene glycol distearate, and organic nitrogen compounds such as nitrogen-containing aromatic compounds such as pyridine, lutidine, collidine and quinolines , Hexylamine, octylamine, decylamine, dodecylamine, tetradecylamine, hexadecylamine, octadecylamine and other amino alkanes, dibutyl sulfide and other dialkyl sulfides, dimethyl sulfoxide and dibutyl sulfoxide and other dialkyl sulfoxides, and thiophene Organic sulfur compounds such as sulfur-containing aromatic compounds, higher fatty acids such as palmitic acid, stearic acid, oleic acid, alcohols, sorbitan fatty acid esters Fatty acid modified polyesters, tertiary amine modified polyurethanes and polyethylene imines, and the like.

  Since the band gap increases as the size of the quantum dot decreases, the size of the quantum dot is adjusted as appropriate so that light of a desired wavelength can be obtained. As the crystal size decreases, the light emission of the quantum dots shifts to the blue side, that is, to the high energy side, so changing the size of the quantum dots changes the spectral wavelengths in the ultraviolet, visible, and infrared regions. The emission wavelength can be adjusted over a region. As the size (diameter) of the quantum dots, those in the range of 0.5 nm to 20 nm, preferably 1 nm to 10 nm are usually used. In addition, as the quantum dot has a narrower size distribution, the emission spectrum becomes narrower and light emission with good color purity can be obtained. Further, the shape of the quantum dots is not particularly limited, and may be a ball field, a rod shape, a disk shape, or other shapes. Note that a quantum rod that is a rod-shaped quantum dot has a function of exhibiting light having directivity, and thus a light-emitting element with better external quantum efficiency can be obtained by using the quantum rod as a light-emitting material.

  By the way, in many cases, the organic EL element increases luminous efficiency by dispersing a light emitting material in a host material and suppressing concentration quenching of the light emitting material. The host material needs to be a material having a singlet excitation energy level or a triplet excitation energy level higher than that of the light emitting material. In particular, when a blue phosphorescent material is used as a light emitting material, a host material having a triplet excitation energy level higher than that and having an excellent lifetime is required, and its development is extremely difficult. Here, since the quantum dots can maintain the light emission efficiency even if the light emitting layer is constituted only by the quantum dots without using the host material, a light emitting element that is preferable from this point of view can also be obtained. When the light emitting layer is formed only with quantum dots, the quantum dots preferably have a core-shell structure (including a core-multishell structure).

  When quantum dots are used for the light-emitting material of the light-emitting layer, the thickness of the light-emitting layer is 3 nm to 100 nm, preferably 10 nm to 100 nm, and the quantum dot content in the light-emitting layer is 1 to 100% by volume. However, it is preferable to form the light emitting layer only with quantum dots. When forming a light emitting layer in which the quantum dots are dispersed in the host as a light emitting material, the quantum dots are dispersed in the host material, or the host material and the quantum dots are dissolved or dispersed in an appropriate liquid medium. (Spin coating method, casting method, die coating method, blade coating method, roll coating method, ink jet method, printing method, spray coating method, curtain coating method, Langmuir-Blodget method, etc.) may be used. For the light-emitting layer using a phosphorescent light-emitting material, in addition to the wet process, a vacuum vapor deposition method can be suitably used.

  Examples of the liquid medium used in the wet process include ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, halogenated hydrocarbons such as dichlorobenzene, and aromatic carbonization such as toluene, xylene, mesitylene, and cyclohexyl benzene. Hydrogen, aliphatic hydrocarbons such as cyclohexane, decalin, and dodecane, and organic solvents such as dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) can be used.

≪A pair of electrodes≫
The electrode 101 and the electrode 102 have a function as an anode or a cathode of the light emitting element. The electrode 101 and the electrode 102 can be formed using a metal, an alloy, a conductive compound, a mixture or a stacked body thereof.

  One of the electrode 101 and the electrode 102 is preferably formed using a conductive material having a function of reflecting light. Examples of the conductive material include aluminum (Al) or an alloy containing Al. Examples of the alloy containing Al include an alloy containing Al and L (L represents one or more of titanium (Ti), neodymium (Nd), nickel (Ni), and lanthanum (La)). For example, Al and Ti, or an alloy containing Al, Ni, and La. Aluminum has a low resistance value and a high light reflectance. In addition, since aluminum is abundant in the crust and inexpensive, manufacturing cost of a light-emitting element by using aluminum can be reduced. Silver (Ag) or Ag and N (N is yttrium (Y), Nd, magnesium (Mg), ytterbium (Yb), Al, Ti, gallium (Ga), zinc (Zn), indium (In) Represents one or more of tungsten (W), manganese (Mn), tin (Sn), iron (Fe), Ni, copper (Cu), palladium (Pd), iridium (Ir), or gold (Au) ) And the like. Examples of the alloy containing silver include an alloy containing silver, palladium and copper, an alloy containing silver and copper, an alloy containing silver and magnesium, an alloy containing silver and nickel, an alloy containing silver and gold, and silver and ytterbium. Examples thereof include alloys. In addition, transition metals such as tungsten, chromium (Cr), molybdenum (Mo), copper, and titanium can be used.

Light emitted from the light-emitting layer is extracted through one or both of the electrode 101 and the electrode 102. Therefore, at least one of the electrode 101 and the electrode 102 is preferably formed using a conductive material having a function of transmitting light. The conductive material is a conductive material having a visible light transmittance of 40% to 100%, preferably 60% to 100%, and a resistivity of 1 × 10 ⁻² Ω · cm or less. Can be mentioned.

Further, the electrode 101 and the electrode 102 may be formed of a conductive material having a function of transmitting light and a function of reflecting light. Examples of the conductive material include a conductive material having a visible light reflectance of 20% to 80%, preferably 40% to 70%, and a resistivity of 1 × 10 ⁻² Ω · cm or less. Can be mentioned. For example, it can be formed using one or more kinds of conductive metals, alloys, conductive compounds, and the like. Specifically, for example, indium tin oxide (hereinafter referred to as ITO), indium tin oxide containing silicon or silicon oxide (abbreviation: ITSO), indium zinc oxide (indium zinc oxide), or titanium is included. Metal oxides such as indium oxide containing indium oxide-tin oxide, indium-titanium oxide, tungsten oxide, and zinc oxide can be used. Alternatively, a metal thin film with a thickness that allows light to pass therethrough (preferably, a thickness of 1 nm to 30 nm) can be used. As the metal, for example, Ag or an alloy such as Ag and Al, Ag and Mg, Ag and Au, Ag and Yb, or the like can be used.

Note that in this specification and the like, the material having a function of transmitting light may be any material that has a function of transmitting visible light and has conductivity. In addition to a physical conductor, an oxide semiconductor or an organic conductor including an organic substance is included. Examples of the organic conductor containing an organic substance include a composite material obtained by mixing an organic compound and an electron donor (donor), and a composite material obtained by mixing an organic compound and an electron acceptor (acceptor). . In addition, an inorganic carbon-based material such as graphene may be used. The resistivity of the material is preferably 1 × 10 ⁵ Ω · cm or less, and more preferably 1 × 10 ⁴ Ω · cm or less.

  One or both of the electrode 101 and the electrode 102 may be formed by stacking a plurality of the above materials.

  In order to improve light extraction efficiency, a material having a higher refractive index than the electrode may be formed in contact with the electrode having a function of transmitting light. Such a material may be a material having a function of transmitting visible light, and may be a material having conductivity or not. For example, in addition to the above oxide conductor, an oxide semiconductor and an organic substance can be given. As an organic substance, the material illustrated to the light emitting layer, the positive hole injection layer, the positive hole transport layer, the electron carrying layer, or the electron injection layer is mentioned, for example. In addition, an inorganic carbon-based material or a metal thin film that transmits light can be used, and a plurality of layers of several nm to several tens of nm may be stacked.

  In the case where the electrode 101 or the electrode 102 has a function as a cathode, it is preferable to use a material having a low work function (3.8 eV or less). For example, elements belonging to Group 1 or Group 2 of the periodic table (alkali metals such as lithium, sodium and cesium, alkaline earth metals such as calcium and strontium, magnesium and the like), alloys containing these elements (for example, Ag And rare earth metals such as Mg, Al and Li), europium (Eu) and Yb, alloys containing these rare earth metals, alloys containing aluminum and silver, and the like can be used.

  In the case where the electrode 101 or the electrode 102 is used as an anode, a material having a high work function (4.0 eV or more) is preferably used.

  Alternatively, the electrode 101 and the electrode 102 may be a stack of a conductive material having a function of reflecting light and a conductive material having a function of transmitting light. In that case, the electrode 101 and the electrode 102 are preferable because they can have a function of adjusting an optical distance so that light having a desired wavelength from each light-emitting layer can resonate and light having a desired wavelength can be strengthened. .

  As a method for forming the electrodes 101 and 102, a sputtering method, a vapor deposition method, a printing method, a coating method, an MBE (Molecular Beam Epitaxy) method, a CVD method, a pulsed laser deposition method, an ALD (Atomic Layer Deposition) method, or the like is appropriately used. be able to.

<< Board >>
The light-emitting element according to one embodiment of the present invention may be manufactured over a substrate formed of glass, plastic, or the like. As the order of manufacturing on the substrate, the layers may be sequentially stacked from the electrode 101 side or may be sequentially stacked from the electrode 102 side.

  Note that as the substrate over which the light-emitting element according to one embodiment of the present invention can be formed, glass, quartz, plastic, or the like can be used, for example. A flexible substrate may be used. The flexible substrate is a substrate that can be bent (flexible), and examples thereof include a plastic substrate made of polycarbonate and polyarylate. Moreover, a film, an inorganic vapor deposition film, etc. can also be used. Note that other materials may be used as long as they function as a support in the manufacturing process of the light-emitting element and the optical element. Or what is necessary is just to have a function which protects a light emitting element and an optical element.

  For example, in the present invention and the like, a light-emitting element can be formed using various substrates. The kind of board | substrate is not specifically limited. Examples of the substrate include a semiconductor substrate (for example, a single crystal substrate or a silicon substrate), an SOI substrate, a glass substrate, a quartz substrate, a plastic substrate, a metal substrate, a stainless steel substrate, a substrate having stainless steel foil, and a tungsten substrate. , A substrate having a tungsten foil, a flexible substrate, a laminated film, a paper containing a fibrous material, or a base film. Examples of the glass substrate include barium borosilicate glass, aluminoborosilicate glass, and soda lime glass. Examples of a flexible substrate, a laminated film, a base film and the like include the following. For example, there are plastics represented by polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), and polytetrafluoroethylene (PTFE). Another example is a resin such as acrylic. Alternatively, examples include polypropylene, polyester, polyvinyl fluoride, and polyvinyl chloride. As an example, there are polyamide, polyimide, aramid, epoxy, an inorganic vapor deposition film, papers, and the like.

  Alternatively, a flexible substrate may be used as the substrate, and the light-emitting element may be formed directly on the flexible substrate. Alternatively, a separation layer may be provided between the substrate and the light-emitting element. The release layer can be used to separate a part from the substrate after the light emitting element is partially or wholly formed thereon, and to transfer the light emitting element to another substrate. At that time, the light-emitting element can be transferred to a substrate having poor heat resistance or a flexible substrate. Note that, for example, a structure of a laminated structure of an inorganic film of a tungsten film and a silicon oxide film or a structure in which a resin film such as polyimide is formed over a substrate can be used for the above-described release layer.

  That is, a light-emitting element may be formed using a certain substrate, and then the light-emitting element may be transferred to another substrate, and the light-emitting element may be disposed on another substrate. As an example of a substrate to which the light emitting element is transferred, in addition to the above-described substrate, a cellophane substrate, a stone substrate, a wood substrate, a cloth substrate (natural fiber (silk, cotton, hemp), synthetic fiber (nylon, polyurethane, polyester) or There are recycled fibers (including acetate, cupra, rayon, recycled polyester), leather substrates, rubber substrates, and the like. By using these substrates, a light-emitting element that is not easily broken, a light-emitting element with high heat resistance, a light-emitting element that is reduced in weight, or a light-emitting element that is thinned can be obtained.

  Further, for example, a field effect transistor (FET) may be formed over the substrate described above, and the light emitting element 150 may be formed over an electrode electrically connected to the FET. Accordingly, an active matrix display device in which driving of the light emitting element 150 is controlled by the FET can be manufactured.

  As described above, the structure described in this embodiment can be combined as appropriate with any of the other embodiments.

(Embodiment 4)
In this embodiment, a light-emitting element having a structure different from that of the light-emitting element described in Embodiment 3 and a light-emitting mechanism of the light-emitting element will be described below with reference to FIGS. I do. In FIGS. 3A and 3B, the same hatch pattern is used for portions having the same functions as those shown in FIGS. 1A to 1C, and the reference numerals are omitted. There is. Moreover, the same code | symbol is attached | subjected to the location which has the same function, and the detailed description may be abbreviate | omitted.

<Configuration Example 3 of Light-Emitting Element>
FIG. 3A is a schematic cross-sectional view of the light-emitting element 250.

  A light-emitting element 250 illustrated in FIG. 3A includes a plurality of light-emitting units (light-emitting units 106 and 110) between a pair of electrodes (the electrodes 101 and 102). Any one of the plurality of light-emitting units preferably has a structure similar to that of the EL layer 100 illustrated in FIG. In other words, the light-emitting element 150 illustrated in FIG. 1A preferably includes one light-emitting unit, and the light-emitting element 250 preferably includes a plurality of light-emitting units. Note that in the light-emitting element 250, the electrode 101 functions as an anode and the electrode 102 functions as a cathode, but the structure of the light-emitting element 250 may be reversed.

  Further, in the light-emitting element 250 illustrated in FIG. 3A, the light-emitting unit 106 and the light-emitting unit 110 are stacked, and a charge generation layer 115 is provided between the light-emitting unit 106 and the light-emitting unit 110. Note that the light emitting unit 106 and the light emitting unit 110 may have the same configuration or different configurations. For example, it is preferable to use a structure similar to that of the EL layer 100 for the light-emitting unit 110.

  In addition, the light-emitting element 250 includes the light-emitting layer 120 and the light-emitting layer 170. In addition to the light emitting layer 170, the light emitting unit 106 includes a hole injection layer 111, a hole transport layer 112, an electron transport layer 113, and an electron injection layer 114. In addition to the light emitting layer 120, the light emitting unit 110 includes a hole injection layer 116, a hole transport layer 117, an electron transport layer 118, and an electron injection layer 119.

  The charge generation layer 115 has a configuration in which an acceptor substance that is an electron acceptor is added to a hole transport material, but a donor substance that is an electron donor is added to the electron transport material. May be. Moreover, both these structures may be laminated | stacked.

In the case where the charge generation layer 115 includes a composite material of an organic compound and an acceptor substance, a composite material that can be used for the hole-injection layer 111 described in Embodiment 3 may be used as the composite material. As the organic compound, various compounds such as an aromatic amine compound, a carbazole compound, an aromatic hydrocarbon, and a high molecular compound (oligomer, dendrimer, polymer, etc.) can be used. Note that an organic compound having a hole mobility of 1 × 10 ⁻⁶ cm ² / Vs or higher is preferably used. Note that other than these substances, any substance that has a property of transporting more holes than electrons may be used. Since a composite material of an organic compound and an acceptor substance is excellent in carrier injecting property and carrier transporting property, low voltage driving and low current driving can be realized. Note that in the case where the surface of the light emitting unit on the anode side is in contact with the charge generation layer 115, the charge generation layer 115 can also serve as a hole injection layer or a hole transport layer of the light emission unit. The unit may not be provided with a hole injection layer or a hole transport layer. Alternatively, when the surface of the light emitting unit on the cathode side is in contact with the charge generation layer 115, the charge generation layer 115 can also serve as an electron injection layer or an electron transport layer of the light emission unit. May have a configuration in which an electron injection layer or an electron transport layer is not provided.

  Note that the charge generation layer 115 may be formed as a stacked structure in which a layer including a composite material of an organic compound and an acceptor substance and a layer formed using another material are combined. For example, a layer including a composite material of an organic compound and an acceptor substance may be formed in combination with a layer including one compound selected from electron donating substances and a compound having a high electron transporting property. Alternatively, a layer including a composite material of an organic compound and an acceptor substance may be combined with a layer including a transparent conductive film.

  Note that the charge generation layer 115 sandwiched between the light-emitting unit 106 and the light-emitting unit 110 injects electrons into one light-emitting unit and applies holes to the other light-emitting unit when voltage is applied to the electrode 101 and the electrode 102. As long as it injects. For example, in FIG. 3A, when a voltage is applied so that the potential of the electrode 101 is higher than the potential of the electrode 102, the charge generation layer 115 injects electrons into the light-emitting unit 106, so that the light-emitting unit 110 Inject holes into

  Note that the charge generation layer 115 preferably has a property of transmitting visible light (specifically, the transmittance of visible light to the charge generation layer 115 is 40% or more) from the viewpoint of light extraction efficiency. In addition, the charge generation layer 115 functions even when it has lower conductivity than the pair of electrodes (the electrode 101 and the electrode 102).

  By forming the charge generation layer 115 using the above-described material, an increase in driving voltage when the light-emitting layer is stacked can be suppressed.

  3A illustrates the light-emitting element having two light-emitting units, the present invention can be similarly applied to a light-emitting element in which three or more light-emitting units are stacked. As shown in the light-emitting element 250, a plurality of light-emitting units are partitioned between a pair of electrodes by a charge generation layer, thereby enabling high-intensity light emission while maintaining a low current density, and a longer-life light-emitting element Can be realized. In addition, a light-emitting element with low power consumption can be realized.

  Note that in each of the above structures, the emission colors exhibited by the guest materials used for the light-emitting unit 106 and the light-emitting unit 110 may be the same as or different from each other. In the case where the light-emitting unit 106 and the light-emitting unit 108 include guest materials having a function of emitting light of the same color, the light-emitting element 250 is preferably a light-emitting element that exhibits high emission luminance with a small current value. In the case where the light emitting unit 106 and the light emitting unit 108 include a guest material having a function of emitting light of different colors, the light emitting element 250 is preferably a light emitting element that exhibits multicolor light emission. In this case, by using a plurality of light-emitting materials having different emission wavelengths for one or both of the light-emitting layer 120 and the light-emitting layer 170, the light emission spectrum exhibited by the light-emitting element 250 is light in which light emission having different emission peaks is synthesized. Therefore, the emission spectrum has at least two maximum values.

  The above configuration is also suitable for obtaining white light emission. White light emission can be obtained by making the lights of the light emitting layer 120 and the light emitting layer 170 have complementary colors. In particular, it is preferable to select the guest material so that white light emission having high color rendering properties or light emission having at least red, green, and blue light is obtained.

In the case of a light-emitting element in which three or more light-emitting units are stacked, the emission colors exhibited by the guest materials used in the respective light-emitting units may be the same or different from each other. In the case of having a plurality of light emitting units that emit light of the same color, the light emission colors exhibited by the plurality of light emitting units can achieve high light emission luminance with a smaller current value than other colors. Such a configuration can be suitably used for adjusting the emission color. In particular, it is suitable when using guest materials that have different luminous efficiencies and exhibit different luminescent colors. For example, in the case of having three layers of light-emitting units, two layers of light-emitting units having the same color fluorescent material and one layer of a light-emitting unit having a phosphorescent material exhibiting an emission color different from the fluorescent material The emission intensity of phosphorescence can be adjusted. That is, the intensity of the emitted color can be adjusted by the number of light emitting units.

In the case of a light-emitting element having two fluorescent light-emitting units and one phosphorescent light-emitting unit, a light-emitting element containing two light-emitting units containing a blue fluorescent material and one light-emitting unit containing a yellow phosphorescent material or blue A light emitting element having two light emitting units containing a fluorescent material and one light emitting layer unit containing a red phosphorescent material and a green phosphorescent material, two light emitting units containing a blue fluorescent material and a red phosphorescent material, a yellow phosphorescent material, and a green phosphorescent material A light-emitting element having one light-emitting layer unit containing a material is preferable because white light emission can be efficiently obtained.

  Further, at least one of the light emitting layer 120 or the light emitting layer 170 may be further divided into layers, and a different light emitting material may be included in each of the divided layers. That is, at least one of the light-emitting layer 120 or the light-emitting layer 170 may be formed of two or more layers. For example, when a light emitting layer is formed by sequentially stacking a first light emitting layer and a second light emitting layer from the hole transport layer side, a material having a hole transport property is used as a host material of the first light emitting layer. There is a configuration in which a material having an electron transporting property is used as the host material of the light emitting layer 2. In this case, the light emitting materials included in the first light emitting layer and the second light emitting layer may be the same material or different materials, and may be different materials that have the function of emitting light of the same color. A material having a function of emitting light of a color may be used. With a structure including a plurality of light emitting materials having a function of emitting light of different colors, white light emission having high color rendering properties composed of three primary colors or four or more light emission colors can be obtained.

In addition, the light emitting layer of the light emitting unit 110 preferably includes a phosphorescent compound. Note that a light-emitting element with favorable heat resistance and light emission efficiency can be provided by applying the organic compound according to one embodiment of the present invention to at least one of the plurality of units.
Note that this embodiment can be combined with any of the other embodiments as appropriate.

(Embodiment 5)
4A is a top view illustrating the light-emitting device, and FIG. 4B is a cross-sectional view taken along lines AB and CD of FIG. 4A. This light-emitting device includes a drive circuit portion (source side drive circuit) 601, a pixel portion 602, and a drive circuit portion (gate side drive circuit) 603 indicated by dotted lines, for controlling light emission of the light emitting element. Reference numeral 604 denotes a sealing substrate, reference numeral 625 denotes a desiccant, reference numeral 605 denotes a sealing material, and the inside surrounded by the sealing material 605 is a space 607.

Note that the routing wiring 608 is a wiring for transmitting a signal input to the source side driving circuit 601 and the gate side driving circuit 603, and a video signal, a clock signal, an FPC (flexible printed circuit) 609 serving as an external input terminal, Receives start signal, reset signal, etc. Although only the FPC is shown here, a printed wiring board (PWB: Printed Writing Board) may be attached to the FPC. The light-emitting device in this specification includes not only a light-emitting device body but also a state in which an FPC or a PWB is attached thereto.

Next, a cross-sectional structure of the light-emitting device is described with reference to FIG. A driver circuit portion and a pixel portion are formed over the element substrate 610. Here, a source side driver circuit 601 that is a driver circuit portion and one pixel in the pixel portion 602 are shown.

Note that the source side driver circuit 601 is a CMOS circuit in which an n-channel TFT 623 and a p-channel TFT 624 are combined. The driving circuit may be formed of various CMOS circuits, PMOS circuits, and NMOS circuits. In this embodiment mode, a driver integrated type in which a drive circuit is formed over a substrate is shown; however, this is not always necessary, and the drive circuit can be formed outside the substrate.

The pixel portion 602 is formed of a pixel including a switching TFT 611, a current control 612, and a first electrode 613 electrically connected to the drain thereof. Note that an insulator 614 is formed so as to cover an end portion of the first electrode 613. The insulator 614 can be formed using a positive tourism resin film.

In order to improve the coverage of the film formed over the insulator 614, a surface having a curvature is formed at the upper end portion or the lower end portion of the insulator 614. For example, when photosensitive acrylic is used as a material for the insulator 614, it is preferable that only the upper end portion of the insulator 614 has a curved surface. The curvature radius of the curved surface is preferably 0.2 μm or more and 0.3 μm or less. Further, as the insulator 614, any of photosensitive materials such as a negative type and a positive type can be used.

An EL layer 616 and a second electrode 617 are formed over the first electrode 613. Here, as a material used for the first electrode 613 functioning as an anode, a material having a high work function is preferably used. For example, an ITO film or an indium tin oxide film containing silicon, a single layer such as an indium oxide film containing 2 wt% or more and 20 wt% or less of zinc oxide, a titanium nitride film, a chromium film, a tungsten film, a Zn film, or a Pt film In addition to the film, a stack of titanium nitride and a film containing aluminum as a main component, a three-layer structure of a titanium nitride film, a film containing aluminum as a main component, and a titanium nitride film can be used. Note that with a stacked structure, resistance as a wiring is low, good ohmic contact can be obtained, and a function as an anode can be obtained.

The EL layer 616 is formed by various methods such as an evaporation method using an evaporation mask, an inkjet method, and a spin coating method. The material forming the EL layer 616 may be a low molecular compound or a high molecular compound (including an oligomer and a dendrimer).

Further, as a material used for the second electrode 617 formed over the EL layer 616 and functioning as a cathode, a material having a low work function (Al, Mg, Li, Ca, or an alloy or compound thereof, MgAg, MgIn, AlLi or the like is preferably used. Note that in the case where light generated in the EL layer 616 passes through the second electrode 617, the second electrode 617 includes a thin metal film and a transparent conductive film (ITO, 2 wt% or more and 20 wt% or less). A stack of indium oxide containing zinc oxide, indium tin oxide containing silicon, zinc oxide (ZnO), or the like is preferably used.

Note that the light-emitting element 618 is formed by the first electrode 613, the EL layer 616, and the second electrode 617. The light-emitting element 618 is preferably a light-emitting element having the structure of Embodiments 1 and 2. Note that a plurality of light-emitting elements are formed in the pixel portion; however, in the light-emitting device in this embodiment, the light-emitting element having the structure described in Embodiments 3 and 4 and other structures are used. Both of the light emitting elements having the above may be included.

Further, the sealing substrate 604 is bonded to the element substrate 610 with the sealant 605, whereby the light-emitting element 618 is provided in the space 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealant 605. Yes. Note that the space 607 is filled with a filler and may be filled with an inert gas (nitrogen, argon, or the like), or may be filled with a resin or a desiccant, or both.

Note that an epoxy resin or glass frit is preferably used for the sealant 605. Moreover, it is desirable that these materials are materials that do not transmit moisture and oxygen as much as possible. In addition to a glass substrate or a quartz substrate, a plastic substrate made of FRP (Fiber Reinforced Plastics), PVF (polyvinyl fluoride), polyester, acrylic, or the like can be used as a material for the sealing substrate 604.

As described above, a light-emitting device using the light-emitting element described in Embodiments 3 and 4 can be obtained.

<Configuration Example 1 of Light-Emitting Device>
FIG. 5 illustrates an example of a light-emitting device in which a light-emitting element that emits white light is formed and a colored layer (color filter) is formed as an example of the light-emitting device.

FIG. 5A shows a substrate 1001, a base insulating film 1002, a gate insulating film 1003, gate electrodes 1006, 1007, and 1008, a first interlayer insulating film 1020, a second interlayer insulating film 1021, a peripheral portion 1042, and a pixel portion. 1040, a driving circuit portion 1041, a first electrode 1024W, 1024R, 1024G, and 1024B of a light emitting element, a partition wall 1026, an EL layer 1028, a second electrode 1029 of the light emitting element, a sealing substrate 1031, a sealing material 1032, and the like are illustrated. ing.

In FIGS. 5A and 5B, colored layers (a red colored layer 1034R, a green colored layer 1034G, and a blue colored layer 1034B) are provided on a transparent substrate 1033. Further, a black layer (black matrix) 1035 may be further provided. The transparent base material 1033 provided with the coloring layer and the black layer is aligned and fixed to the substrate 1001. Note that the colored layer and the black layer are covered with an overcoat layer 1036. In FIG. 5A, there are a light emitting layer in which light is emitted outside without passing through the colored layer, and a light emitting layer in which light is emitted through the colored layer of each color and is transmitted through the colored layer. Since the light that does not pass is white, and the light that passes through the colored layer is red, blue, and green, an image can be expressed by pixels of four colors.

FIG. 5B illustrates an example in which a red colored layer 1034R, a green colored layer 1034G, and a blue colored layer 1034B) are formed between the gate insulating film 1003 and the first interlayer insulating film 1020. As illustrated in FIG. 5B, the coloring layer may be provided between the substrate 1001 and the sealing substrate 1031.

In the light-emitting device described above, a light-emitting device having a structure in which light is extracted to the substrate 1001 side where the TFT is formed (bottom emission type) is used. However, a structure in which light is extracted from the sealing substrate 1031 side (top-emission type). ).

<Configuration Example 2 of Light Emitting Device>
A cross-sectional view of a top emission type light emitting device is shown in FIG. In this case, a substrate that does not transmit light can be used as the substrate 1001. Until the connection electrode for connecting the TFT and the anode of the light emitting element is manufactured, it is formed in the same manner as the bottom emission type light emitting device. Thereafter, a third interlayer insulating film 1037 is formed so as to cover the electrode 1022. This insulating film may play a role of planarization. The third interlayer insulating film 1037 can be formed using various other materials in addition to the same material as the second interlayer insulating film 1021.

The first lower electrodes 1025W, 1025R, 1025G, and 1025B of the light emitting elements are anodes here, but may be cathodes. In the case of a top emission type light emitting device as shown in FIG. 7, the lower electrodes 1025W, 1025R, 1025G, and 1025B are preferably reflective electrodes. Note that the second electrode 1029 preferably has a function of reflecting light and a function of transmitting light. In addition, it is preferable that a microcavity structure be applied between the second electrode 1029 and the lower electrodes 1025W, 1025R, 1025G, and 1025B to have a function of amplifying light of a specific wavelength. The EL layer 1028 has a structure as described in Embodiment 2 and has an element structure in which white light emission can be obtained.

In FIG. 5A, FIG. 5B, and FIG. 6, the structure of the EL layer that can emit white light may be realized by using a plurality of light-emitting layers, a plurality of light-emitting units, or the like. . The configuration for obtaining white light emission is not limited to these.

In the top emission structure as shown in FIG. 6, sealing can be performed with a sealing substrate 1031 provided with colored layers (red colored layer 1034R, green colored layer 1034G, and blue colored layer 1034B). A black layer (black matrix) 1030 may be provided on the sealing substrate 1031 so as to be positioned between the pixels. The colored layer (red colored layer 1034R, green colored layer 1034G, blue colored layer 1034B) or black layer (black matrix) may be covered with an overcoat layer. Note that the sealing substrate 1031 is a light-transmitting substrate.

Although an example in which full color display is performed with four colors of red, green, blue, and white is shown here, the present invention is not particularly limited, and full color display may be performed with three colors of red, green, and blue. Further, full color display may be performed with four colors of red, green, blue, and yellow.

As described above, a light-emitting device using the light-emitting element described in Embodiments 3 and 4 can be obtained.

Note that although not illustrated here, the organic compound according to one embodiment of the present invention can be used for an organic thin film solar cell. More specifically, since it has carrier transportability, it can be used for a carrier transport layer and a carrier injection layer. Further, since it is optically excited, it can be used as a power generation layer.

Note that this embodiment can be combined with any of the other embodiments as appropriate.

(Embodiment 6)
In this embodiment, an electronic device of one embodiment of the present invention will be described.

According to one embodiment of the present invention, a highly reliable electronic device having a flat surface can be manufactured. According to one embodiment of the present invention, a highly reliable electronic device having a curved surface can be manufactured. Further, according to one embodiment of the present invention, an electronic device having flexibility and high reliability can be manufactured.

Electronic devices include, for example, television devices, desktop or notebook personal computers, monitors for computers, digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, personal digital assistants, audio devices Large game machines such as playback devices and pachinko machines are listed.

In addition, the light-emitting device of one embodiment of the present invention can achieve high visibility regardless of the intensity of external light. Therefore, it can be suitably used for a portable electronic device, a wearable electronic device (wearable device), an electronic book terminal, and the like.

A portable information terminal 900 illustrated in FIGS. 7A and 7B includes a housing 901, a housing 902, a display portion 903, a hinge portion 905, and the like.

The housing 901 and the housing 902 are connected by a hinge portion 905. The portable information terminal 900 can be developed from the folded state (FIG. 7A) as shown in FIG. 7B. Thereby, when carrying, it is excellent in portability, and when using, it is excellent in visibility by a large display area.

The portable information terminal 900 is provided with a flexible display portion 903 across a housing 901 and a housing 902 connected by a hinge portion 905.

A light-emitting device manufactured using one embodiment of the present invention can be used for the display portion 903. Thereby, a portable information terminal can be manufactured with a high yield.

The display unit 903 can display at least one of document information, a still image, a moving image, and the like. When displaying document information on the display unit, the portable information terminal 900 can be used as an electronic book terminal.

When the portable information terminal 900 is deployed, the display unit 903 is held in a greatly curved form. For example, the display portion 903 is held including a curved portion with a curvature radius of 1 mm to 50 mm, preferably 5 mm to 30 mm. Part of the display portion 903 can display a curved surface by continuously arranging pixels from the housing 901 to the housing 902.

The display portion 903 functions as a touch panel and can be operated with a finger or a stylus.

The display unit 903 is preferably composed of one flexible display. Accordingly, it is possible to perform continuous display without interruption between the housing 901 and the housing 902. Note that a display may be provided in each of the housing 901 and the housing 902.

The hinge unit 905 preferably has a lock mechanism so that the angle between the housing 901 and the housing 902 does not become larger than a predetermined angle when the portable information terminal 900 is deployed. For example, it is preferable that the angle at which the lock is applied (not opened further) is 90 degrees or more and less than 180 degrees, typically 90 degrees, 120 degrees, 135 degrees, 150 degrees, or 175 degrees. be able to. Thereby, the convenience, safety | security, and reliability of the portable information terminal 900 can be improved.

When the hinge portion 905 has a lock mechanism, the display portion 903 can be prevented from being damaged without applying excessive force to the display portion 903. Therefore, a highly reliable portable information terminal can be realized.

The housing 901 and the housing 902 may include a power button, an operation button, an external connection port, a speaker, a microphone, and the like.

One of the housing 901 and the housing 902 is provided with a wireless communication module, and can transmit data via a computer network such as the Internet, a LAN (Local Area Network), or Wi-Fi (Wireless Fidelity: registered trademark). It is possible to send and receive.

A portable information terminal 910 illustrated in FIG. 8C includes a housing 911, a display portion 912, operation buttons 913, an external connection port 914, a speaker 915, a microphone 916, a camera 917, and the like.

A light-emitting device manufactured using one embodiment of the present invention can be used for the display portion 912. Thereby, a portable information terminal can be manufactured with a high yield.

The portable information terminal 910 includes a touch sensor in the display unit 912. All operations such as making a call or inputting characters can be performed by touching the display portion 912 with a finger or a stylus.

Further, by operating the operation button 913, the power can be turned on and off, and the type of the image displayed on the display unit 912 can be switched. For example, the mail creation screen can be switched to the main menu screen.

Further, by providing a detection device such as a gyro sensor or an acceleration sensor inside the portable information terminal 910, the orientation (portrait or landscape) of the portable information terminal 910 is determined, and the screen display orientation of the display unit 912 is determined. It can be switched automatically. The screen display orientation can also be switched by touching the display portion 912, operating the operation buttons 913, or inputting voice using the microphone 916.

The portable information terminal 910 has one or more functions selected from, for example, a telephone, a notebook, an information browsing device, or the like. Specifically, it can be used as a smartphone. The portable information terminal 910 can execute various applications such as mobile phone, electronic mail, text browsing and creation, music playback, video playback, Internet communication, and games.

A camera 920 illustrated in FIG. 8D includes a housing 921, a display portion 922, operation buttons 923, a shutter button 924, and the like. A removable lens 926 is attached to the camera 920.

A light-emitting device manufactured using one embodiment of the present invention can be used for the display portion 922. Thereby, a camera can be manufactured with a high yield.

Here, the camera 920 is configured such that the lens 926 can be removed from the housing 921 and replaced, but the lens 926 and the housing 921 may be integrated.

The camera 920 can capture a still image or a moving image by pressing the shutter button 924. In addition, the display portion 922 has a function as a touch panel and can capture an image by touching the display portion 922.

The camera 920 can be separately attached with a strobe device, a viewfinder, and the like. Alternatively, these may be incorporated in the housing 921.

7A to 7E illustrate electronic devices. These electronic devices include a housing 9000, a display portion 9001, a speaker 9003, operation keys 9005 (including a power switch or an operation switch), a connection terminal 9006, and a sensor 9007 (force, displacement, position, speed, acceleration, angular velocity, rotation) Number, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, smell, or infrared) And a microphone 9008 and the like.

A light-emitting device manufactured using one embodiment of the present invention can be favorably used for the display portion 9001. Thereby, an electronic device can be manufactured with a high yield.

The electronic devices illustrated in FIGS. 7A to 7E can have various functions. For example, a function for displaying various information (still images, moving images, text images, etc.) on the display unit, a touch panel function, a function for displaying a calendar, date or time, a function for controlling processing by various software (programs), Wireless communication function, function for connecting to various computer networks using the wireless communication function, function for transmitting or receiving various data using the wireless communication function, and reading and displaying the program or data recorded on the recording medium It can have a function of displaying on the section. Note that the functions of the electronic devices illustrated in FIGS. 7A to 7E are not limited to these, and may have other functions.

8A is a perspective view illustrating a wristwatch-type portable information terminal 9200, and FIG. 8B is a perspective view illustrating a wristwatch-type portable information terminal 9201.

A portable information terminal 9200 illustrated in FIG. 8A can execute various applications such as a mobile phone, e-mail, text browsing and creation, music playback, Internet communication, and computer games. Further, the display portion 9001 is provided with a curved display surface, and can perform display along the curved display surface. In addition, the portable information terminal 9200 can execute short-range wireless communication with a communication standard. For example, it is possible to talk hands-free by communicating with a headset capable of wireless communication. In addition, the portable information terminal 9200 includes a connection terminal 9006 and can directly exchange data with other information terminals via a connector. Charging can also be performed through the connection terminal 9006. Note that the charging operation may be performed by wireless power feeding without using the connection terminal 9006.

A mobile information terminal 9201 illustrated in FIG. 8B is different from the mobile information terminal illustrated in FIG. 8A in that the display surface of the display portion 9001 is not curved. In addition, the external shape of the display portion of the portable information terminal 9201 is a non-rectangular shape (a circular shape in FIG. 8B).

8C to 8E are perspective views illustrating a foldable portable information terminal 9202. FIG. Note that FIG. 8C is a perspective view of a state in which the portable information terminal 9202 is expanded, and FIG. 8D is a state in which the portable information terminal 9202 is expanded or changed from one of the folded state to the other. FIG. 8E is a perspective view of the portable information terminal 9202 folded.

The portable information terminal 9202 is excellent in portability in the folded state, and in the expanded state, the portable information terminal 9202 is excellent in display listability due to a seamless wide display area. A display portion 9001 included in the portable information terminal 9202 is supported by three housings 9000 connected by a hinge 9055. By bending between the two housings 9000 via the hinge 9055, the portable information terminal 9202 can be reversibly deformed from the expanded state to the folded state. For example, the portable information terminal 9202 can be bent with a curvature radius of 1 mm to 150 mm.

This embodiment can be combined with any of the other embodiments as appropriate.

(Embodiment 7)
In this embodiment, examples of applying the light-emitting element of one embodiment of the present invention to various lighting devices will be described with reference to FIGS.

  By manufacturing the light-emitting element of one embodiment of the present invention over a flexible substrate, an electronic device or a lighting device having a light-emitting region having a curved surface can be realized.

  The light-emitting device to which the light-emitting element of one embodiment of the present invention is applied can also be used for lighting of a car. For example, lighting can be provided on a windshield, a ceiling, or the like.

  9A shows a perspective view of one surface of the multifunction terminal 3500, and FIG. 9B shows a perspective view of the other surface of the multifunction terminal 3500. In the multi-function terminal 3500, a display portion 3504, a camera 3506, an illumination 3508, and the like are incorporated in a housing 3502. The light-emitting device of one embodiment of the present invention can be used for the lighting 3508.

  The illumination 3508 functions as a surface light source by using the light-emitting device of one embodiment of the present invention. Therefore, unlike a point light source typified by an LED, light emission with less directivity can be obtained. For example, when the lighting 3508 and the camera 3506 are used in combination, the lighting 3508 can be turned on or blinked and an image can be captured by the camera 3506. Since the illumination 3508 has a function as a surface light source, it can capture a photograph taken under natural light.

  Note that the multi-function terminal 3500 illustrated in FIGS. 9A and 9B can have various functions like the electronic devices illustrated in FIGS. 7A to 7C.

  In addition, a speaker, a sensor (force, displacement, position, velocity, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current are provided inside the housing 3502. , Voltage, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared measurement function), microphone, and the like. Further, by providing a detection device having a sensor for detecting inclination such as a gyroscope and an acceleration sensor inside the multi-function terminal 3500, the orientation (vertical or horizontal) of the multi-function terminal 3500 is determined, and a display unit 3504 is provided. The screen display can be automatically switched.

  The display portion 3504 can also function as an image sensor. For example, personal authentication can be performed by touching the display portion 3504 with a palm or a finger and capturing a palm print, a fingerprint, or the like. In addition, when a backlight that emits near-infrared light or a sensing light source that emits near-infrared light is used for the display portion 3504, finger veins, palm veins, and the like can be imaged. Note that the light-emitting device of one embodiment of the present invention may be applied to the display portion 3054.

  FIG. 9C shows a perspective view of a security light 3600. The light 3600 includes an illumination 3608 outside the housing 3602, and the housing 3602 incorporates a speaker 3610 and the like. The light-emitting element of one embodiment of the present invention can be used for the lighting 3608.

  As the light 3600, for example, light can be emitted by gripping, holding, or holding the illumination 3608. Further, an electronic circuit that can control a light emission method from the light 3600 may be provided inside the housing 3602. As the electronic circuit, for example, a circuit that can emit light once or intermittently a plurality of times may be used, or a circuit that can adjust the light emission amount by controlling the light emission current value. Good. In addition, a circuit that outputs a loud alarm sound from the speaker 3610 at the same time as the light emission of the illumination 3608 may be incorporated.

  Since the light 3600 can emit light in all directions, for example, it can be threatened with light or light and sound toward a thief or the like. The light 3600 may be provided with a camera such as a digital still camera and a function having a photographing function.

  FIG. 10 illustrates an example in which the light-emitting element is used as an indoor lighting device 8501. Note that since the light-emitting element can have a large area, a large-area lighting device can be formed. In addition, by using a housing having a curved surface, the lighting device 8502 in which the light-emitting region has a curved surface can be formed. The light-emitting element described in this embodiment is thin and has a high degree of freedom in housing design. Therefore, it is possible to form a lighting device with various designs. Further, a large lighting device 8503 may be provided on the indoor wall surface. Alternatively, the lighting devices 8501, 8502, and 8503 may be provided with touch sensors to turn the power on or off.

  In addition, by using the light-emitting element on the surface side of the table, the lighting device 8504 having a function as a table can be obtained. Note that a lighting device having a function as furniture can be obtained by using a light-emitting element as part of other furniture.

  As described above, a lighting device and an electronic device can be obtained by using the light-emitting device of one embodiment of the present invention. Note that applicable lighting devices and electronic devices are not limited to those described in this embodiment and can be applied to electronic devices in various fields.

  The structure described in this embodiment can be combined as appropriate with any of the structures described in the other embodiments.

In this example, 3,5-bis (3- (9H-2-methylcarbazol-9-yl) phenyl) pyridine (abbreviation: Me-35DCzPPy) which is one of the organic compounds according to one embodiment of the present invention is used. A synthesis method of (Structural Formula (100)) and physical properties of the compound will be described.

<Synthesis Example 1>
<Step 1: Synthesis of 2-methyl-9- (bromobenzene-3-yl) carbazole>
In a 100 mL three-necked flask, 5.8 g (32 mmol) of 2-methylcarbazole, 19 mL (0.16 mol) of 3-dibromobenzene, and potassium carbonate 5. g (38 mmol) and 18-crown-6-ether 0.84 g (3.2 mmol) were added, and the atmosphere in the flask was replaced with nitrogen. The mixture was degassed by stirring under reduced pressure, and 0.61 g (3.2 mmol) of copper iodide was added, followed by heating at 180 ° C. for 30 hours under a nitrogen stream. After a predetermined time, the mixture was cooled to room temperature. Toluene was added to the mixture, and the mixture was passed through a filter aid filled in the order of Celite, alumina, and Florisil. The obtained filtrate was concentrated and purified by silica gel column chromatography (developing solvent: hexane), and 7.8 g of a colorless liquid of 2-methyl-9- (bromobenzene-3-yl) carbazole which was the target product. And the yield was 73%. The synthesis scheme of Step 1 is shown in the following formula (S-1).

<Step 2: Synthesis of 3- (2-methyl-9H-carbazol-9-yl) phenylboronic acid>
To a 300 mL three-necked flask, 5.2 g (15 mmol) of 2-methyl-9- (3-bromophenyl) carbazole was added, and the atmosphere in the flask was replaced with nitrogen. To this was added 150 mL of anhydrous tetrahydrofuran, and the mixture was cooled to −80 ° C. under a nitrogen stream. After cooling, 12 mL (19 mmol) of 1.6 M n-butyllithium was added dropwise to the solution. This solution was stirred at the same temperature for 30 minutes. After a predetermined time, 2.6 mL (23 mmol) of trimethyl borate was added, the temperature was raised to room temperature, and the mixture was stirred for 18 hours. After a predetermined time, 100 mL of 1M hydrochloric acid was added to this mixture, extraction with ethyl acetate was performed, and the solvent was distilled off to obtain a white solid. The obtained solid hexane suspension was irradiated with ultrasonic waves, and the solid was collected by suction filtration. As a result, 4- (2-methyl-9H-carbazol-9-yl) phenylboronic acid, a white solid, was obtained. .3 g, yield 92%. The synthesis scheme of Step 2 is shown by the following formula (S-2).

<Step 3: Synthesis of 3,5-bis (3- (9H-2-methylcarbazol-9-yl) phenyl) pyridine (abbreviation: Me-35DCzPPy)>

In a 200 mL three-necked flask, 1.5 g (6.4 mmol) of 3,5-dibromopyridine, 4.3 g (14 mmol) of 3- (2-methyl-9H-carbazol-9-yl) phenylboronic acid, tri (orthotolyl) phosphine 0 .39 g (1.3 mmol), potassium carbonate 3.5 g (26 mmol), toluene 60 mL, ethanol 12 mL, and water 6.0 mL were added. The mixture was degassed by stirring under reduced pressure, and the atmosphere in the flask was replaced with nitrogen. To this mixture, 58 mg (0.26 mmol) of palladium (II) acetate was added, and the mixture was stirred at 80 ° C. for 44 hours under a nitrogen stream. After elapse of a predetermined time, extraction with toluene was performed and purification was performed by silica gel column chromatography (developing solvent: toluene) to obtain a yellow powder. When this yellow powder was recrystallized using ethyl acetate, 2.0 g of a target white powder was obtained in a yield of 54%. The synthesis scheme of Step 1 is shown in the following formula (A-1).

Sublimation purification of 2.0 g of the obtained white powder was performed by a train sublimation method. The sublimation purification was performed by heating at a pressure of 2.2 Pa, an argon flow rate of 10 ml / min, and 310 ° C. After sublimation purification, 1.2 g of the target white solid was obtained with a recovery rate of 60%.

The analysis data of the obtained solid by nuclear magnetic resonance spectroscopy (1H NMR) are shown below.
¹ H NMR (chloroform-d, 300 MHz): δ = 8.94 (d, J = 2.0 Hz, 2H), 8.14 (t, J = 1.9 Hz, 1H), 8.08-8.12. (M, 2H), 8.02 (d, J = 7.8 Hz, 2H), 7.83-7.86 (m, 2H), 7.72-7.77 (m, 4H), 7.60 -7.67 (m, 2H), 7.33-7.44 (m, 4H), 7.27-7.31 (m, 2H), 7.20-7.24 (m, 2H), 7 .10-7.14 (m, 2H)

Further, FIG. 11A and FIG. 11B show 1H NMR charts of the obtained solid. Note that FIG. 11B is an enlarged view of the range of 7.0 ppm to 9.0 ppm in FIG. From the measurement results, it was found that the target product, Me-35DCzPPy, was obtained.

<Characteristics of Me-35DCzPPy>
Next, Me-35DCzPPy obtained in this Example was analyzed by liquid chromatography mass spectrometry (Liquid Chromatography Mass Spectrometry, abbreviation: LC / MS analysis).

In LC / MS analysis, LC (liquid chromatography) separation was performed by Acquity UPLC manufactured by Waters, and MS analysis (mass spectrometry) was performed by Xevo G2 Tof MS manufactured by Waters. The column used for the LC separation was Acquity UPLC BEH C8 (2.1 × 100 mm 1.7 μm), and the column temperature was 40 ° C. As the mobile phase, mobile phase A was acetonitrile and mobile phase B was 0.1% formic acid aqueous solution. The sample was prepared by dissolving Me-35DCzPPy of an arbitrary concentration in toluene and diluting with acetonitrile, and the injection amount was 5.0 μL.

For the LC separation, a gradient method for changing the composition of the mobile phase was used. From the start of measurement to 0 to 1 minute, the mobile phase A: mobile phase B = 65: 35, and then the composition was changed to change the mobile phase A at 10 minutes. And the mobile phase B were such that the ratio of mobile phase A: mobile phase B = 95: 5. The composition was changed linearly.

In MS analysis, ionization by electrospray ionization (ElectroSpray Ionization (abbreviation: ESI)) was performed. At this time, the capillary voltage was 3.0 kV, the sample cone voltage was 30 V, and the detection was performed in the positive mode. Further, the components ionized under the above conditions were collided with argon gas in the collision chamber (collision cell) and dissociated into product ions. The energy (collision energy) for collision with argon was 70 eV. The mass range to be measured was m / z = 100 to 1200. FIG. 12 shows the result of detecting dissociated product ions by time-of-flight (TOF) type MS.

From the results of FIG. 12, it was found that product ions were detected mainly in the vicinity of m / z = 574, 409, and 180 in Me-35DCzPPy. In addition, since the result shown in FIG. 12 shows the characteristic result derived from Me-35DCzPPy, it can be said that it is important data in identifying Me-35DCzPPy contained in a mixture.

The product ion in the vicinity of m / z = 574 is assumed to be a radical cation in a state in which the methyl group in Me-35DCzPPy is represented by C42H28N3. ⁺ (• represents a radical cation), and m The product ion near / z = 409 is presumed to be a radical cation with 2-methylcarbazole desorbed in Me-35DCzPPy represented by C30H21N2 ⁺ , and the product ion near m / z = 180 is C13H10N -It is presumed to be a radical cation of 2-methylcarbazole in Me-35DCzPPy represented by ⁺ , and suggests that Me-35DCzPPy contains a 2-methylcarbazole skeleton. In addition, ± 1 of the product ion may be detected as a proton addition / desorption body.

  Next, the absorption spectrum and emission spectrum of Me-35DCzPPy in a toluene solution are shown in FIG.

An absorption spectrum and an emission spectrum of a toluene solution of Me-35DCzPPy are shown in FIG. Further, FIG. 14 shows an absorption spectrum and an emission spectrum of the thin film. The solid thin film was prepared on a quartz substrate by a vacuum deposition method. For the measurement of the absorption spectrum of the toluene solution, an ultraviolet-visible spectrophotometer (model V550 manufactured by JASCO Corporation) was used. The absorption spectrum of the Me-35DCzPPy solution shown in FIG. 13 was obtained by subtracting the absorption spectrum of toluene measured by putting only toluene in a quartz cell from the absorption spectrum of the toluene solution of Me-35DCzPPy. Further, a spectrophotometer (Spectrophotometer U4100 manufactured by Hitachi High-Technologies Corporation) was used for measuring the absorption spectrum of the thin film. In addition, a fluorometer (FS920 manufactured by Hamamatsu Photonics Co., Ltd.) was used for measuring the emission spectrum.

From FIG. 13, the absorption peak of the toluene solution of Me-35DCzPPy was observed at around 323 nm and 338 nm, and similarly, from FIG. 13, the peak of the emission wavelength was 373 nm (excitation wavelength: 333 nm). Further, from FIG. 14, the Me-35DCzPPy thin film has absorption peaks around 210 nm, 243 nm, 295 nm, 326 nm, and 338 nm. Similarly, from FIG. It was seen. Therefore, it was found that Me-35DCzPPy which is one embodiment of the present invention emits light and can also be used as a light-emitting material.

Moreover, the phosphorescence spectrum of the thin film of Me-35DCzPPy was measured and the T1 level was determined. For the measurement, a micro-PL device LabRAM HR-PL (Horiba, Ltd.) was used, the measurement temperature was 10K, a He-Cd laser (325 nm) was used as excitation light, and a CCD detector was used as the detector. The first peak on the short wavelength side of this phosphorescence is 451 nm (2.75 eV), and has a high T1 level, and was found to be suitable as a host for a blue phosphorescent emission center material.

Further, it was found that the thin film of Me-35DCzPPy has a good film quality that hardly aggregates even in the air and has little change in form.

The HOMO level and LUMO level of Me-35DCzPPy were calculated based on cyclic voltammetry (CV) measurement. The calculation method is shown below.

As a measuring device, an electrochemical analyzer (manufactured by BAS Co., Ltd., model number: ALS model 600A or 600C) was used. As a solution in CV measurement, dehydrated dimethylformamide (DMF) (manufactured by Aldrich, 99.8%, catalog number: 22705-6) was used as a solvent, and tetra-n-butylammonium perchlorate (supporting electrolyte) ( n-Bu ₄ NClO ₄ ) (manufactured by Tokyo Chemical Industry Co., Ltd., catalog number: T0836) is dissolved to a concentration of 100 mmol / L, and the measurement target is further dissolved to a concentration of 2 mmol / L. did. In addition, as a working electrode, a platinum electrode (manufactured by BAS Co., Ltd., PTE platinum electrode), and as an auxiliary electrode, a platinum electrode (manufactured by BAS Inc., Pt counter electrode for VC-3 ( 5 cm)), and Ag / Ag ⁺ electrode (manufactured by BAS Co., Ltd., RE7 non-aqueous solvent system reference electrode) was used as a reference electrode. The measurement was performed at room temperature (20 to 25 ° C.). Further, the scanning speed during CV measurement was unified to 0.1 V / sec, and the oxidation potential Ea [V] and the reduction potential Ec [V] with respect to the reference electrode were measured. Ea was an intermediate potential of the oxidation-reduction wave, and Ec was an intermediate potential of the reduction-oxidation wave. Here, since it is known that the potential energy with respect to the vacuum level of the reference electrode used in this example is −4.94 [eV], the HOMO level [eV] = − 4.94−Ea, LUMO. From the equation of level [eV] = − 4.94−Ec, the HOMO level and the LUMO level can be obtained respectively.

As a result, it was found that the HOMO level was −5.84 eV in the measurement of the oxidation potential Ea [V] of Me-35DCzPPy. On the other hand, the LUMO level was found to be -2.39 eV.

Further, differential scanning calorimetry (DSC measurement) of Me-35DCzPPy was measured using Pyris 1 DSC manufactured by PerkinElmer. Differential scanning calorimetry was performed by increasing the temperature at a temperature increase rate of 50 ° C./min.

From the DSC measurement results of the second cycle, Me-35DCzPPy has a glass transition point of 129 ° C., which indicates that the material has high heat resistance.

In this example, a manufacturing example of a light-emitting element including an organic compound according to one embodiment of the present invention and characteristics of the light-emitting element will be described. A comparative light-emitting element was also manufactured. A cross-sectional view of the element structure manufactured in this example is the same as FIG. Details of the element structure are shown in Table 1. The structures and abbreviations of the compounds used are shown below. For other organic compounds, the previous examples may be referred to.

In this example, 35DCzPPy was used as the host material and the electron transport layer of the light emitting layer in the comparative light emitting element 1, and Me-35DCzPPy was used as the evaporation source of the host material and the electron transport layer material of the light emitting element 2.

Table 4 shows values of HOMO and LUMO calculated by CV measurement of 35DCzPPy and Me-35DCzPPy used as the host material and the electron transport layer material in this example. This physical property value is such that a small difference is observed in the HOMO level.

<Production of light-emitting element>
<< Production of Comparative Light-Emitting Element 1 >>
An ITSO film having a thickness of 70 nm was formed as an electrode 101 on a glass substrate. The electrode area of the electrode 101 was 4 mm ² (2 mm × 2 mm).

Next, as a hole injection layer 111 over the electrode 101, 1,3,5-tri- (4-dibenzothiophenyl) -benzene (abbreviation: DBT3P-II) and MoO ₃ are mixed in a weight ratio (DBT3P— II: MoO ₃ ) was co-deposited so that the ratio was 1: 0.5 and the thickness was 20 nm.

  Next, 9-phenyl-9H-3- (9-phenyl-9H-carbazol-3-yl) carbazole (abbreviation: PCCP) is formed to a thickness of 20 nm as the hole transport layer 112 over the hole injection layer 111. It vapor-deposited so that it might become.

Next, PCCP, 35DCzPPy, and tris {2- [5- (2-methylphenyl) -4- (2,6-diisopropylphenyl) -4H are formed on the hole-transporting layer 112 as the light-emitting layer 140 (1). -1,2,4-triazol-3-yl-κN ² ] phenyl-κC} iridium (III) (abbreviation: Ir (mppptz-diPrp) ₃ ) so that the weight ratio is 1: 0.3: 0.06 And the light-emitting layer 140 (2) is co-evaporated so that the weight ratio (35DCzPPy: Ir (mppptz-diPrp) ₃ ) is 1: 0.06, and Co-evaporation was performed so as to have a thickness of 10 nm Note that Ir (mppptz-diPrp) ₃ is a phosphorescent light emitting guest material in the light emitting layer 140 (1) and the light emitting layer 140 (2).

  Next, 35DCzPPy was co-evaporated as a first electron-transport layer 118- (1) onto the light-emitting layer 140 (2) so as to have a thickness of 10 nm. Subsequently, bathophenanthroline (abbreviation: BPhen) was deposited as a second electron transport layer 118- (2) on the first electron transport layer 118- (1) so as to have a film thickness of 15 nm.

Next, lithium fluoride (LiF) was deposited as an electron injection layer 119 on the second electron transport layer 118- (2) so as to have a thickness of 1 nm.

  Next, aluminum (Al) was formed as the electrode 102 over the electron injection layer 119 so as to have a thickness of 200 nm.

Next, the light-emitting elements 1 to 6 are sealed by fixing a glass substrate for sealing with an organic EL sealing material in a nitrogen atmosphere glove box to a glass substrate on which an organic material is formed. did. Specifically, a sealing material is applied around the organic material on the glass substrate on which the organic material is formed, the substrate and the glass substrate for sealing are bonded, and ultraviolet light with a wavelength of 365 nm is applied to 6 J / Irradiated with cm ² and heat-treated at 80 ° C. for 1 hour. Through the above steps, Light-Emitting Element 1 to Light-Emitting Element 6 were obtained.

<< Production of Light-Emitting Element 2 >>
The light-emitting element 2 is different from the comparative light-emitting element 1 described above only in the process of forming the light-emitting layer 140 and the electron transport layer 118, and the other processes are the same as those of the comparative light-emitting element 1.

As the light-emitting layer 140 (1) of the light-emitting element 2, PCCP, Me-35DCzPPy, and Ir (mpppz-diPrp) ₃ have a weight ratio of 1: 0.3: 0.06 and a thickness of 30 nm. Next, as a light emitting layer 140 (2), the weight ratio (Me-35DCzPPy: Ir (mpppz-diPrp) ₃ ) is 1: 0.06 and the thickness is 10 nm. Co-deposited so that Note that in the light-emitting layer 140 (1) and the light-emitting layer 140 (2), Ir (mppptz-diPrp) ₃ is a guest material that exhibits phosphorescence.

  Next, Me-35DCzPPy was co-evaporated on the light-emitting layer 140 (2) so as to have a thickness of 10 nm as the first electron-transport layer 118- (1). Subsequently, bathophenanthroline (abbreviation: BPhen) was deposited as a second electron transport layer 118- (2) on the first electron transport layer 118- (1) so as to have a film thickness of 15 nm.

<Characteristics of light emitting element>
Next, the characteristics of the comparative light-emitting element 1 and the light-emitting element 2 manufactured as described above were measured. A color luminance meter (Top-5, BM-5A) was used for measurement of luminance and CIE chromaticity, and a multi-channel spectrometer (PMA-11, manufactured by Hamamatsu Photonics) was used for measurement of electroluminescence spectrum.

  FIG. 15 shows current efficiency-luminance characteristics of the comparative light-emitting element 1 and the light-emitting element 2. Further, FIG. 16 shows current density-voltage characteristics. Further, the external quantum efficiency-luminance characteristics are shown in FIG. Note that each light-emitting element was measured at room temperature (atmosphere kept at 23 ° C.).

Table 3 shows element characteristics of the comparative light-emitting element 1 and the light-emitting element ^{2 in the} vicinity of 1000 cd / m ² .

In addition, FIG. 18 shows an electroluminescence spectrum of the light-emitting element 1 to the light-emitting element 6 when current is supplied at a current density of ^2.5 mA / cm ² .

  As shown in FIG. 15, FIG. 17 and Table 3, the current efficiency and the external quantum efficiency of the comparative light-emitting element 1 and the light-emitting element 2 were almost equal, and no significant difference was observed. Moreover, the maximum values of the external quantum time efficiencies were 27% or more, respectively, indicating good efficiency.

In addition, from FIG. 16 and Table 3, the driving voltages of the comparative light-emitting element 1 and the light-emitting element 2 are almost the same, and a large difference was not seen. In addition, each of the blue phosphorescent elements having a voltage of 4.6 V or less near 1000 cd / m ² has a low driving voltage and good power efficiency.

The HCMO level of PCCP is −5.63 eV, which is sufficiently higher than the HOMO level of Me-35DCzPPy (−5.84 eV). In addition, Me-35DCzPPy or 35DCzPPy and PCCP are co-evaporated on the light emitting layer 140 (1). Therefore, it is considered that holes are mainly transported by PCCP. It is considered that electrons are mainly transported by Me-35DCzPPy and 35DCzPPy having a pyridine ring.

Further, as shown in FIG. 18, Comparative Light-Emitting Element 1 and Light-Emitting Element 2 exhibited blue light emission having an electroluminescence spectrum peak wavelength of 477 nm and a full width at half maximum of 70 nm and 69 nm, respectively. From the obtained electroluminescence spectrum, it can be seen that light is emitted from Ir (mppptz-diPrp) ₃ which is a guest material. Further, as shown in FIG. 20, the electroluminescence spectra obtained from the comparative light-emitting element 1 and the light-emitting element 2 were almost the same, and no great difference was observed.

The T1 level of Me-35DCzPPy was 2.75 eV, whereas the T1 level of 35DCzPPy was also 2.75 eV. This also indicates that even when a saturated aliphatic hydrocarbon group is substituted at the 2-position or 7-position of the carbazolyl group of the organic compound according to one embodiment of the present invention, the T1 level is not significantly affected. .

As described above, the element characteristics of the comparative light-emitting element 1 using 35DCzPPy and the light-emitting element 2 using the organic compound Me-35DCzPPy which is one embodiment of the present invention were almost equal.

Here, Tg of 35DCzPPy and Me-35DCzPPy is shown in Table 4. The measurement method is the same as in the previous example.

From Table 4, it can be seen that Me-35DCzPPy has a higher Tg than 35DCzPPy and has improved heat resistance. From the above, when Me-35DCzPPy and 35DCzPPy were compared, it was found that when both were used for the light-emitting element, Me-35DCzPPy had improved heat resistance, although the element characteristics were equivalent.

As described above, when an alkyl group or a cycloalkyl group is introduced into an organic compound having a carbazole skeleton used for a light-emitting element, a compound in which a substituent is introduced at the 2-position or 7-position of the carbazole skeleton Heat resistance can be improved while maintaining device characteristics equivalent to those of organic compounds.

100 EL layer 101 Electrode 102 Electrode 106 Light emitting unit 108 Light emitting unit 110 Light emitting unit 111 Hole injection layer 112 Hole transport layer 113 Electron transport layer 114 Electron injection layer 115 Charge generation layer 116 Hole injection layer 117 Hole transport layer 118 Electron Transport layer 118- Electron transport layer 119 Electron injection layer 120 Light-emitting layer 140 Light-emitting layer 141 Host material 141_1 Organic compound 141_2 Organic compound 142 Guest material 150 Light-emitting element 152 Light-emitting element 170 Light-emitting layer 180 Under nitrogen stream 250 Light-emitting element 545T Coumarin 600A ALS model 601 Source side driving circuit 602 Pixel portion 603 Gate side driving circuit 604 Sealing substrate 605 Sealing material 607 Space 608 Wiring 610 Element substrate 611 Switching TFT
612 Current control 613 Electrode 614 Insulator 616 EL layer 617 Electrode 618 Light emitting element 623 n-channel TFT
624 p-channel TFT
900 Mobile information terminal 901 Case 902 Case 903 Display unit 905 Hinge unit 910 Mobile information terminal 911 Case 912 Display unit 913 Operation button 914 External connection port 915 Speaker 916 Microphone 917 Camera 920 Camera 921 Case 922 Display unit 923 Operation button 924 Shutter button 926 Lens 1001 Substrate 1002 Base insulating film 1003 Gate insulating film 1006 Gate electrode 1007 Gate electrode 1008 Gate electrode 1020 Interlayer insulating film 1021 Interlayer insulating film 1022 Electrode 1024B Electrode 1024G Electrode 1024R Electrode 1025B Lower electrode 1025G Lower electrode 1025R Lower electrode 1026 Partition wall 1028 EL layer 1029 Electrode 1031 Sealing substrate 1032 Sealing material 1033 Base material 1034B Colored layer 1034G Colored layer 1034R Colored Layer 1036 Overcoat layer 1037 Interlayer insulating film 1040 Pixel portion 1041 Drive circuit portion 1042 Peripheral portion 3054 Display portion 3500 Multifunctional terminal 3502 Housing 3504 Display portion 3506 Camera 3508 Lighting 3600 Light 3602 Housing 3608 Lighting 3610 Speaker 8501 Lighting device 8502 Lighting Device 8503 Lighting device 8504 Lighting device 9000 Housing 9001 Display unit 9003 Speaker 9005 Operation key 9006 Connection terminal 9007 Sensor 9008 Microphone 9055 Hinge 9200 Portable information terminal 9201 Portable information terminal 9202 Portable information terminal

Claims (15)

An organic compound represented by the following general formula (G0).

(In General Formula (G0), A represents a nitrogen-containing heteroaromatic ring, and any one of B ^{1 to} B ⁴ is an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted C 3 to 7 carbon atoms. Represents a cycloalkyl group, and the others and R ^{1 to} R ¹² are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted group. Any one of the aryl groups having 6 to 13 carbon atoms, Ar ¹ and Ar ² each independently represents a substituted or unsubstituted arylene group having 6 to 25 carbon atoms, and n and k are integers of 0 to 3 M represents an integer of 1 to 3.) The compound represented by the following general formula (G1).

(In General Formula (G1), A represents a nitrogen-containing heteroaromatic ring, and any one of B ^{1 to} B ⁴ is an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted C 3 to 7 carbon atoms. Each of the others independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted carbon group having 6 to 13 carbon atoms. Ar ¹ and Ar ² each independently represents a substituted or unsubstituted arylene group having 6 to 25 carbon atoms, n and k each represents an integer of 0 to 3, and m represents 1 Represents an integer of 3 to 3.) The compound represented by the following general formula (G2).

(In General Formula (G2), A represents a nitrogen-containing heteroaromatic ring, and any one of B ^{1 to} B ⁴ is an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted C 3 to 7 carbon atoms. Each of the others independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted carbon group having 6 to 13 carbon atoms. And n and k each represents an integer of 0 to 3, and m represents an integer of 1 to 3.) The compound represented by the following general formula (G3).

(In General Formula (G3), A represents a nitrogen-containing heteroaromatic ring, and any one of B ^{1 to} B ⁴ is an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted C 3 to 7 carbon atoms. Each of the others independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted carbon group having 6 to 13 carbon atoms. Or an aryl group of In any one of Claims 1 thru | or 4,
An organic compound in which the nitrogen-containing heteroaromatic ring has 1 to 5 carbon atoms. In any one of Claims 1 thru | or 4,
An organic compound in which the nitrogen-containing heteroaromatic ring is any one of pyridine, diazine, and triazine. In any one of said Claims 1 thru | or 6.
An organic compound in which any one of B ^{1 to} B ⁴ is a methyl group. A compound represented by the following structural formula (100).

  The light emitting element which has a compound as described in any one of Claims 1 thru | or 8. An EL layer between the pair of electrodes;
The EL layer has a light emitting layer and an electron transport layer,
The light emitting element which has a compound as described in any one of Claims 1 thru | or 9 in at least one of the said light emitting layer or the said electron carrying layer. In claim 9 or claim 10,
The light emitting element in which the material whose HOMO level is higher than the compound as described in any one of Claim 1 thru | or 10 is contained 10% or more by weight ratio in a light emitting layer. A light emitting unit having the light emitting element according to any one of claims 9 to 11,
And a light emitting device. A light emitting device according to claim 12,
At least one of a housing and a touch sensor;
Electronic equipment having A light emitting device according to claim 12,
Case, connection terminal, or protective cover,
A lighting device comprising: A compound represented by the following structural formula (500) or (501).

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