JP4839717B2 - Organic electroluminescence element, display device and lighting device - Google Patents

Description

  The present invention relates to an organic electroluminescence element, a display device, and a lighting device.

  Conventionally, there is an electroluminescence display (ELD) as a light-emitting electronic display device. Examples of the constituent elements of ELD include inorganic electroluminescent elements and organic electroluminescent elements (hereinafter also referred to as organic EL elements). Inorganic electroluminescent elements have been used as planar light sources, but an alternating high voltage is required to drive the light emitting elements.

  On the other hand, an organic EL element has a configuration in which a light emitting layer containing a compound that emits light is sandwiched between a cathode and an anode, and injects electrons and holes into the light emitting layer to recombine excitons. This is an element that emits light by utilizing the emission of light (fluorescence / phosphorescence) when this exciton is deactivated, and can emit light at a voltage of several volts to several tens of volts. Therefore, it has a wide viewing angle, high visibility, and since it is a thin-film type completely solid element, it has attracted attention from the viewpoints of space saving and portability.

  For the development of organic EL elements for practical use in the future, organic EL elements that emit light efficiently and with high luminance with lower power consumption are desired. For example, stilbene derivatives, distyrylarylene derivatives or A technique for doping a trisstyrylarylene derivative with a small amount of a phosphor to improve emission luminance and extend the lifetime of the device (see, for example, Patent Document 1), and using 8-hydroxyquinoline aluminum complex as a host compound. A device having an organic light emitting layer doped with a trace amount of a phosphor (see, for example, Patent Document 2), a device having an organic light emitting layer doped with a quinacridone dye as a host compound using 8-hydroxyquinoline aluminum complex ( For example, see Patent Document 3).

  In the technique disclosed in the above-mentioned patent document, when the emission from the excited singlet is used, the generation ratio of the singlet exciton and the triplet exciton is 1: 3, so the generation probability of the luminescent excited species is 25%. Since the light extraction efficiency is about 20%, the limit of the external extraction quantum efficiency (ηext) is set to 5%.

  However, since Princeton University has reported on organic EL devices that use phosphorescence from excited triplets (see, for example, Non-Patent Document 1), research on materials that exhibit phosphorescence at room temperature has become active. (For example, refer nonpatent literature 2 and patent literature 4.). When excited triplets are used, the upper limit of internal quantum efficiency is 100%, so in principle the luminous efficiency is four times that of excited singlets, and the performance is almost the same as that of cold cathode tubes. It can be applied to and attracts attention. For example, many compounds have been studied for synthesis centering on heavy metal complexes such as iridium complexes (see, for example, Non-Patent Document 3).

  Currently, further enhancement of light emission efficiency and long life of organic EL elements using phosphorescence is being actively studied. One example is the multilayered element structure. Early organic EL devices have a single-layer structure in which a light-emitting layer is sandwiched between an anode and a cathode. In this case, all of carrier injection, movement, and light emission must be performed with only the light-emitting layer, and the efficiency is very low. It was. Thereafter, it has been developed into a multilayer (laminated structure) element in which functions such as carrier injection, movement, block, and light emission are separated, and has made great progress in terms of higher efficiency and longer life.

  On the other hand, in increasing the area of an organic EL element, it is known that the production by vacuum vapor deposition, which is common in the production of an organic EL element using a low molecular weight compound, has problems in terms of equipment and energy efficiency. Therefore, it is considered that a printing method including an ink jet method or a screen printing method or a coating method such as spin coating or cast coating is desirable.

  For example, when a white light-emitting element is manufactured, a plurality of light-emitting compounds having different emission maximum wavelengths must be provided in the light-emitting layer. In particular, in the case of a phosphorescent light-emitting element, a plurality of phosphorous compounds are formed by vacuum evaporation. It is difficult to deposit the photo-dopant at the same ratio every time, and it is expected that there will be a problem in the yield at the time of manufacture, but organic EL by the printing method and the coating method using a material having excellent solvent solubility. If the device can be manufactured, the phosphorescent dopant in the same ratio can be added to any organic EL device manufactured by preparing a solution in which the phosphorescent dopant is mixed in the same ratio. In addition, a white light-emitting organic EL element having the same luminescent color can be stably produced.

  Although this coating method has many advantages, it cannot be said that the required elements such as higher efficiency of light emission and longer life are still sufficient, and further improvement is required.

  The development of the above-mentioned multilayer (laminated structure) device is a solution for improving the light emission efficiency and extending the life of the coating method, but in the case of the coating method, the surface of the lower layer thin film is disturbed by the upper coating solvent. Therefore, the formation of the laminated film required for the organic EL element is a very difficult problem.

  Furthermore, as a common problem of multilayer (laminated structure) devices, performance degradation is likely to occur due to problems such as adhesion between adjacent layers and energy barriers. There is a strong demand for means and methods for comprehensively solving these issues.

As a multilayer (laminated structure) element by a coating method, an EL element in which three layers of “hole transport (injection) layer / light emitting layer / electron transport (hole blocking) layer” are formed by a coating method has been reported ( For example, see Non-Patent Document 4 and Patent Document 5), but the performance is still not sufficient, and further progress is desired.
Japanese Patent No. 3093796 Japanese Unexamined Patent Publication No. 63-264692 JP-A-3-255190 US Pat. No. 6,097,147 Japanese Patent Laid-Open No. 2005-2603 M.M. A. Baldo et al. , Nature, 395, 151-154 (1998) M.M. A. Baldo et al. , Nature, 403, 17, 750-753 (2000) S. Lamansky et al. , J .; Am. Chem. Soc. , 123, 4304 (2001) IDW IV 04 Proceedings P1343

  An object of the present invention is to provide an organic EL element, a lighting device, and a display device that exhibit high external extraction quantum efficiency, have a long light emission lifetime, and have a low driving voltage.

The above object of the present invention has been achieved by the following constitutions 1 to 5 .

1. In the organic electroluminescence device having at least three organic layers including a light emitting layer, a hole transport layer and an electron transport layer as a constituent layer between the cathode and the anode,
A coating solution comprising a mixed region between layer A and layer B, which is at least two layers of the organic layer, wherein the layer A contains a light emitting host material and a phosphorescent light emitting material. A light-emitting layer formed by coating, and layer B is a hole transport layer or an electron transport layer formed by coating a coating solution composed of a non-aqueous solvent that does not contain the phosphorescent light-emitting material . ,且 one, in the mixing region, the organic electroluminescence element concentration distribution of the phosphorescent light emitting material, characterized in that it presents a continuous density gradient.

2. 2. The organic electroluminescence device as described in 1 above, which emits white light.

3. A display device comprising the organic electroluminescence element as described in 1 or 2 above.

4). 3. An illuminating device comprising the organic electroluminescence element as described in 1 or 2 above.

5. 5. A display device comprising the illumination device according to 4 and a liquid crystal element as display means.

  According to the present invention, it was possible to provide an organic EL element, a lighting device, and a display device that exhibit high external extraction quantum efficiency, have a long light emission lifetime, and a low driving voltage.

  In the organic EL device of the present invention, by having the configuration according to any one of claims 1 to 5, the external extraction quantum efficiency is high, the light emission lifetime is long, and the driving voltage for driving the device It has been found that an organic EL element with reduced can be obtained. In addition, by using the organic EL element, the present inventors have succeeded in obtaining a high-luminance display device and a lighting device.

  Hereinafter, details of each component according to the present invention will be sequentially described.

《Mixed area》
The mixed region provided in the constituent layer of the organic EL element of the present invention will be described.

  When an organic electroluminescent element (organic EL element), particularly a multilayered element, is to be produced by a conventionally known coating method, the surface of the lower layer thin film is likely to be disturbed when the upper layer is formed, and a laminated film required for the organic EL element The formation of is a very difficult problem.

  Furthermore, as a common problem of multilayer (laminated structure) elements, the fabricated elements tend to suffer performance degradation due to problems such as adhesion between adjacent layers, energy barriers, etc. It is a big barrier to production.

  As a result of various investigations by the present inventors on the means for solving these problems, the mixing region according to the present invention is provided between the lower layer and the upper layer provided so as to be adjacent to each other by utilizing the characteristics of the coating method. Thus, it has been found that the above problems can be solved.

  In other words, by forming a mixed region having gradation (continuous concentration change) between layers, the apparent energy barrier can be lowered, so that injection and movement of charges (holes, carriers) between layers are significantly facilitated (charges). Improved injection efficiency and improved efficiency by improving charge injection balance). In addition, since there is no clear boundary between layers, the interlayer adhesion of the constituent layers is greatly improved, and effects such as a life improvement effect by reducing stress between layers can be obtained.

(Mixed area with continuous concentration gradient)
In the mixing region according to the present invention, the constituent component for forming the lower layer and / or the constituent component for forming the upper layer before the mixing region is formed have a continuous concentration gradient (concentration gradient continuously in the mixing region). It is also characterized by having

  Here, the mixing region having a continuous concentration gradient will be specifically described with reference to FIGS.

  FIG. 8 is a schematic view showing an example of the organic EL device of the present invention in which a mixed region is formed between the light emitting layer and the electron transport layer, and FIG. 9 is a diagram between the light emitting layer and the electron transport layer. FIG. 6 is a schematic diagram showing an example in which the concentration distribution of the light emitting material constituting the light emitting layer shows a continuous concentration gradient in the mixed region formed in FIG.

  Note that specific means for adjusting the constituent materials so as to exhibit a continuous concentration gradient in the mixed region will be described in the mixed region forming method described later.

  The mixed region according to the present invention is not a mixed layer formed by simply mixing the constituent components of the lower light-emitting layer and the constituent components of the upper electron-transporting layer as described in a conventionally known document. 8. As shown in FIG. 9, the composition changes continuously only in the depth direction (the concentration gradient of the constituent material changes continuously) over the entire interface between the light emitting layer and the electron transport layer, and the light emitting surface. The tendency of the concentration gradient is the same, and there is no unevenness in the concentration change.

  The formation of the mixed region according to the present invention in the entire interface between the light emitting layer and the electron transport layer will be described in detail in the analysis method of concentration gradient described later. By selecting and analyzing in the depth direction (in this application, secondary mass spectrometry is used), a mixed region having a continuous concentration gradient is formed, and the tendency of the concentration gradient is the same in the light emitting surface. I have confirmed.

  By forming a mixed region in which the concentration distribution of the constituent components has a continuous concentration gradient, it is possible to effectively prevent deterioration in device performance due to local changes and electrolytic concentration due to unevenness of the interface. This is not an improvement in adhesion due to the anchor effect, but a continuous change is made, and an interface is not formed, so that an “layer does not exist” effect (also referred to as a seamless effect) is produced.

Since the present invention is a problem caused by "interlayer adhesion, energy gap between layers, etc." between layers, "organic EL element having three or more organic layers" having a plurality of organic layers-organic layers In the present invention, a remarkable effect is exhibited, and a thin film formation method by coating is used as a means for solving the problem. Therefore, “it is desirable to form at least two layers by a coating method”
(Thickness of the mixed region)
The thickness of the mixed region is preferably 0% <x <100%, more preferably 0% <x <50%, more preferably 10% <, where x is the sum of the thicknesses of adjacent layers. It is preferable to adjust to x <30%.

(Method for forming mixed region)
The formation of the mixed region according to the organic EL element of the present invention will be described using, for example, the mixed region of FIG. 8. The mixed region shown in FIG. 8 is between the lower layer (light emitting layer) and the upper layer (electron transport layer). At least one of the components of the light emitting layer (or at least one of the components of the electron transport layer) may have a continuous concentration gradient (or concentration distribution) in the mixed region. In the invention, the formation of the lower layer and / or the upper layer may be either a film formation by a coating method or a film formation by a vapor deposition method. From the viewpoint of easily producing a mixed region, a film formation method by a coating method is used. Is preferably used.

  The reason is that in film formation by vapor deposition, it is possible to form a film having a mixed region with gradation (continuous concentration change) by multi-component co-evaporation, but it requires a continuous change in vapor deposition rate, which is very This is because a complicated and precise operation is required, whereas a method using a coating method as appropriate is very simple and has great manufacturing merit.

Here, specific means for adjusting the gradation using a coating method are as follows:
(A) Apply the upper layer with a solution containing a solvent within the range of the solubility parameter of the lower layer,
(B) The content of the solvent within the range of the solubility parameter of the lower layer is preferably in the range of 0% by mass to 100% by mass, and more preferably adjusted in the range of 0% by mass to 50% by mass.
(Solubility parameter)
Here, the solubility parameter of the lower layer will be described.

  In the present invention, the solubility parameter (SP) at the absolute temperature T of the liquid is represented by the following general formula.

(General formula)
SP = {(ΔH−RT) / V} ^1/2
The unit of SP (solubility parameter) is (cal / cm ³ ) ^1/2 = (MPa) ^1/2
ΔH is the heat of vaporization, V is the molar volume, R is the gas constant, and T is the absolute temperature (K).

(Measurement method of solubility parameter of lower layer)
The method for measuring the solubility parameter used in the present invention was performed as follows.

  First, a plurality of types of solvents having known solubility parameters (see the solvent handbook) and slightly different solubility parameters are prepared. Separately, a lower layer was formed on a 30 mm × 30 mm glass substrate so as to have a thickness of about 50 nm, and 1 ml of the above-described solvent alone was spin-coated under the conditions of 1000 rpm and 30 seconds. After completion, it was confirmed by visual inspection whether or not the coating film had changed. The above operation is sequentially performed in the ascending order of the solubility parameter, and the minimum value and the maximum value are obtained from the solubility parameters of the solvent in which the thin film dissolves, and defined as the range of the solubility parameter of the lower layer.

(C) Cooling the substrate provided with the lower layer (lower layer solubility can be reduced and complete dissolution of the lower layer during upper layer application can be prevented),
(D) Cooling the substrate provided with the lower layer + cooling the upper layer coating liquid (raising the viscosity of the upper layer coating liquid and preventing penetration and dissolution of the lower layer),
Moreover, when a preferable means is mentioned,
(E) It is preferable to cool the method (a) + substrate (reducing the solubility of the lower layer and preventing complete dissolution of the lower layer during the upper layer application),
(F) The method of (a) + cooling the substrate + cooling the upper layer coating liquid (for the purpose of increasing the viscosity of the upper layer coating liquid and preventing penetration and dissolution of the lower layer),
(G) In particular, in the case of the above (c) and / or (e), the material contained in the upper layer coating liquid is a highly amorphous material (a material having a high amorphous property) exhibiting physicochemical properties as shown below. It is preferable to use
Etc.

《High amorphous material》
The highly amorphous material used in the present invention will be described.

  Here, the highly amorphous material means that the material for the organic EL element is dissolved at a certain concentration, and when the prepared solution is cooled to a certain temperature, within 30 minutes after reaching the preset temperature, It is defined as a material that does not visually change, such as turbidity or crystal precipitation.

  At this time, as the “certain specific concentration”, a preferable concentration is preferably within a range of 0.1% by mass to 5% by mass, more preferably within a range of 0.3% by mass to 2% by mass, and particularly preferably. Is adjusting to the range of 0.5 mass%-1 mass%.

  In addition, as the “certain specific temperature”, a preferable temperature is preferably adjusted to an arbitrary temperature within a range of −50 ° C. to 20 ° C., and more preferably an arbitrary temperature within a range of −20 ° C. to 20 ° C. It is a temperature, and particularly preferably an arbitrary temperature in the range of −20 ° C. to 0 ° C.

  As the highly amorphous material, a compound having a structure represented by any one of the following general formulas (1) to (3) is preferably used.

In the formula, R ₁ , R ₂ , R ₃ and R ₄ each represent a substituent, m1 and n1 each represent an integer of 0 to 4, and m2 and n2 each represent an integer of 0 to 6. Z represents a hole transport material residue or an electron transport residue, and the hole transport residue is a group derived from a hole transport material (also referred to as a hole transport compound) described later, the electron The transportable residue represents a group (also referred to as a residue) derived from an electron transporting material (also referred to as an electron transporting compound) described later, a hole transporting group included in an inclusion compound described later, and the like.

  In each of the general formulas (1) to (3), the substituent represented by R is an alkyl group (for example, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group). Octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, etc.), cycloalkyl group (eg, cyclopentyl group, cyclohexyl group etc.), alkenyl group (eg, vinyl group, allyl group etc.), alkynyl group (eg, Ethynyl group, propargyl group etc.), aryl group (eg phenyl group, naphthyl group etc.), aromatic heterocyclic group (eg furyl group, thienyl group, pyridyl group, pyridazinyl group, pyrimidinyl group, pyrazinyl group, triazinyl group, Imidazolyl, pyrazolyl, thiazolyl, quinazolinyl, carbazolyl, carbo Nyl group, diazacarbazolyl group (in which one of carbon atoms constituting the carboline ring of the carbolinyl group is replaced with a nitrogen atom), phthalazinyl group, etc.), heterocyclic group (for example, pyrrolidyl group, Imidazolidyl group, morpholyl group, oxazolidyl group, etc.), alkoxy group (for example, methoxy group, ethoxy group, propyloxy group, pentyloxy group, hexyloxy group, octyloxy group, dodecyloxy group, etc.), cycloalkoxy group (for example, Cyclopentyloxy group, cyclohexyloxy group, etc.), aryloxy group (eg, phenoxy group, naphthyloxy group, etc.), alkylthio group (eg, methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group) Etc.), cycloal Ruthio group (eg, cyclopentylthio group, cyclohexylthio group, etc.), arylthio group (eg, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyl) Oxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (eg, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl group (eg, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butyl) Aminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, Phthalylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), acyl group (for example, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl) Group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group (for example, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.) ), Amide group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, Chlohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc., carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethyl) Aminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group Group), ureido group (for example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, Tilureido group, dodecylureido group, phenylureido group naphthylureido group, 2-pyridylaminoureido group, etc.), sulfinyl group (for example, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecyl) Sulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group, etc.), alkylsulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group) Etc.), arylsulfonyl group or heteroarylsulfonyl group (for example, phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfo group) Nyl group, etc.), amino group (for example, amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, naphthylamino group, 2-pyridylamino group) Etc.), halogen atoms (eg fluorine atom, chlorine atom, bromine atom etc.), fluorinated hydrocarbon groups (eg fluoromethyl group, trifluoromethyl group, pentafluoroethyl group, pentafluorophenyl group etc.), cyano group Nitro group, hydroxy group, mercapto group, silyl group (for example, trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group, phenyldiethylsilyl group, etc.).

  Among these, preferred substituents are an alkyl group and an aryl group, more preferably a methyl group and a phenyl group, and particularly preferably a methyl group.

  These substituents may be further substituted with the above substituents. In addition, a plurality of these substituents may be bonded to each other to form a ring.

  Specific examples of the highly amorphous material represented by any one of the general formulas (1) to (3) (specific examples of the electron transport material and the hole transport material) are shown below. It is not limited to.

(Mixed region concentration gradient analysis method)
In the mixed region of the organic EL element of the present invention, in order to confirm that the concentration distribution of at least one of the constituent components of the constituent layers adjacent to the mixed region shows a continuous concentration gradient, By analyzing the concentration of the target element in the depth direction of the mixed region using a mass spectrometry (SIMS) apparatus, a concentration profile of the target element over the entire region can be obtained.

<< Method for producing organic EL element >>
As an example of the method for producing the organic EL device of the present invention, a method for producing an organic EL device comprising an anode / anode buffer layer / hole transport layer / light emitting layer / electron transport layer / cathode buffer layer / cathode will be described.

  First, on a suitable substrate, a thin film made of a desired electrode material, for example, a material for an anode, is applied according to the present invention so as to have a film thickness of 1 μm or less, preferably 10 nm to 200 nm. The details of the coating will be described later), and the anode is formed by a method such as vapor deposition or sputtering. Next, the constituent layers of the organic EL element (hole transport layer, light emitting layer, electron transport layer, etc.) and inorganic compound layer (anode buffer layer, cathode buffer layer, etc.), which are constituent layers of the organic EL element, are formed thereon. Let As with the anode, coating, vapor deposition, sputtering, and the like can be used for the cathode.

  As a method for forming an anode, a cathode, and an organic layer and an inorganic compound layer provided between the anode and the cathode according to the present invention, a vapor deposition method and a coating method can be used. (Solution coating or dispersion coating may be used).

  In addition, as a coating method, there is a so-called wet process (spin coating method, casting method, ink jet method, printing method), etc., but it is easy to obtain a uniform film, and pinholes are not easily generated. A spin coating method, an ink jet method, a printing method and the like are particularly preferably used. Further, a different film forming method may be applied for each layer. The details of the application will be described later in the application.

  The thickness of each of the organic layer (also referred to as organic compound layer) and the inorganic compound layer according to the present invention is desirably selected as appropriate in the range of 0.1 nm to 5 μm, preferably 5 nm to 200 nm.

When a vapor deposition method (vacuum vapor deposition method, etc.) is used in combination with the preparation of the constituent layers of the organic EL element (anode, cathode, organic layer, inorganic compound layer, etc.), the vapor deposition conditions vary depending on the type of compound used. In general, the boat heating temperature is 50 ° C. to 450 ° C., the degree of vacuum is 10 ⁻⁶ Pa to 10 ⁻² Pa, the deposition rate is 0.01 nm / second to 50 nm / second, and the substrate temperature is −50 ° C. to 300 ° C. It is preferable to adjust the conditions.

  The layer configuration and constituent materials of the organic EL element of the present invention will be described in detail separately.

<Application>
Application | coating which concerns on the manufacturing method of the organic EL element of this invention is demonstrated.

  The coating solution used for coating according to the method for producing an organic EL element of the present invention may be a solution in which the constituent material of the organic EL element is uniformly dissolved, and the constituent material of the constituent layer is dispersed as a solid content. Liquid may be used.

  The coating solution is prepared as appropriate by dissolving a forming material such as a cathode, an anode or an organic layer in a solvent (which may function as a dispersion medium), or in the form of particles (primary particles or secondary particles). Particles may be formed) to prepare a dispersion.

(Non-aqueous solvent)
The nonaqueous solvent according to the present invention will be described.

  In preparing a coating solution (which may be a solution or a dispersion), one of preferred embodiments according to the present invention is to use a non-aqueous solvent.

  Here, the non-aqueous solvent represents a solvent that does not substantially contain water, but “a solvent that does not substantially contain water has a water content of 0.1% by mass or less”. A non-aqueous solvent is defined, and the water content in the solvent can be measured by a conventionally known Karl Fischer moisture meter, an automatic moisture measuring device, or the like.

(Non-aqueous dispersion)
The non-aqueous dispersion according to the present invention will be described.

  The non-aqueous dispersion according to the present invention refers to the above non-aqueous solvent as a dispersion solvent in a fine particle dispersion (in the case of using a plurality of types of dispersion solvents, the main component is 50% by volume or more of the constituent dispersion solvents). The non-aqueous solvent is preferably a solvent other than water, preferably an alcohol, nitrile or hydrocarbon solvent (specifically, an aromatic solvent shown below). And the like.

  In addition, as a combination of the material for forming the anode, the cathode, and the organic layer, and the solvent, it is preferable to select an optimal combination as appropriate according to the type of the organic layer.

  In the preparation of the coating liquid, in the present invention, the solute concentration is in the range of 0.01% by mass to 10% by mass (in the case of a dispersion, the solid content in the dispersion is 0.01% of the total mass of the dispersion). (Range of mass% to 50 mass%) is preferable, and in the preparation of the dispersion, it is preferable to adjust so that the particle diameter of the dispersed particles is 1 μm or less.

(Solvent used for coating solution preparation)
The solvent used in the coating solution is not particularly limited and may be appropriately selected. Examples thereof include halogen solvents such as chloroform, carbon tetrachloride, dichloromethane, 1,2-dichloroethane, dichlorobenzene, dichlorohexanone, acetone, and methyl ethyl ketone. , Ketone solvents such as diethyl ketone, methyl isobutyl ketone, n-propyl methyl ketone, cyclohexanone, aromatic solvents such as benzene, toluene, xylene, ethyl acetate, n-propyl acetate, n-butyl acetate, methyl propionate, Ester solvents such as ethyl propionate, γ-butyrolactone and diethyl carbonate, ether solvents such as tetrahydrofuran and dioxane, amide solvents such as dimethylformamide and dimethylacetamide, methanol, ethanol, 1-butanol, ethyl Alcohol solvents such as glycol, acetonitrile, nitrile solvents such as propionitrile, dimethyl sulfoxide, water, mixed solvents thereof, and the like. Among these solvents, the solvents include water, alcohol solvents such as methanol, 1-butanol and ethylene glycol, ether solvents such as tetrahydrofuran and dioxane, amide solvents such as dimethylformamide and dimethylacetamide, and mixed solvents thereof. When is used, a hydrophilic coating solution is obtained.

  Among them, when preparing a dispersion, any dispersion solvent may be used as long as it does not dissolve the dispersion medium, but alcohol solvents and nitrile solvents are preferable, and methanol, ethanol, acetonitrile, and propionitrile are more preferable. .

  Moreover, as a boiling point of a solvent, 60 to 200 degreeC is preferable, More preferably, it is the range of 80 to 180 degreeC.

(Viscosity of coating solution)
The viscosity of the coating solution is preferably 0.5 mPa · s to 500 mPa · s, more preferably 1 mPa · s to 100 mPa, from the viewpoint of reducing coating unevenness during drying and facilitating adjustment of the dry film thickness. -It is preferable to adjust to the range of s.

  The viscosity of the coating solution can be appropriately adjusted to a desired range by adjusting the temperature, pressure, etc. during the coating, and the viscosity can be determined by a conventionally known rotational viscometer or B-type viscosity. It can be measured using a meter.

  The kind of the coating liquid can be appropriately selected according to the constituent material of the organic EL element, and may be a hydrophilic coating liquid or an oleophilic coating liquid.

(Coating liquid application method and means)
As the coating method of the coating solution, for example, a dipping method, a spin coating method, a casting method, a die coating method, a roll coating method, a blade coating method, a bar coating method, a gravure coating method, etc. are particularly preferably performed. Can do. Among these, it is preferable to use a coater as the coating means, and it is particularly preferable to use a discharge type coater among the coaters.

  In the case of using a discharge type coater, a mode in which a precision diaphragm pump is provided and the coating liquid is discharged by driving the precision diaphragm pump is preferable.

  In this case, the discharge amount of the coating liquid can be easily controlled, and can be applied over a large area, and can be applied precisely, in a thin layer, and in any shape, so that the organic light emitting device has high luminance and excellent luminous efficiency. Is very advantageous in that it can be obtained efficiently at low cost.

(Drying after application)
The drying conditions are not particularly limited, but it is preferable to employ a temperature, pressure, etc. in a range that does not damage the coated layer.

  Further, when a dispersion is used at the time of application, it is preferable to form a constituent layer of the organic EL element after application, after drying of the solvent or while drying. It is preferable that the film is formed at a temperature higher than the glass transition point (Tg) of the material of the main component forming this (this main component is also the main component in the solid content dissolved in the coating solution).

  Further, as shown in (d) above, the three constituent layers A, B, and C of the organic layer of the organic EL element are formed after the constituent layer A is formed, then the constituent layer B, and then the constituent layer C. Is applied to form a continuous layer, the constituent layer A contains the main component A, the constituent layer B contains the main component B, and the constituent layer C contains the main component C. The glass transition point Tg-A of A, the glass transition point Tg-B of the main component B, and the glass transition point Tg-C of the main component C preferably satisfy the inequality (1).

  Here, the glass transition points (Tg-A, B, C) of the main components A, B, and C can be determined by a conventionally known method (DSC (Differential Scanning Colorimetry)). .

<Fine particle dispersion>
For coating according to the present invention, a dispersion liquid in which components of the constituent layers (anode, cathode, organic layer, etc.) of the organic EL element are dispersed in the coating liquid as a solid content can be used. The coating is preferably performed in the state of a fine particle dispersion in which the solid content is finely dispersed in the coating liquid.

(Preparation method of fine particle dispersion)
As a method for preparing the fine particle dispersion, a conventionally known method for producing a fine particle dispersion can be used. For example, there are dispersion by a physical force using a homogenizer (high pressure, ultrasonic wave, etc.), a bead mill, a jet mill, and an optimizer, and emulsification dispersion. In addition to the above method, in the case of a polymer material, polymer fine particles are synthesized by a method such as gas phase polymerization, emulsion polymerization, suspension polymerization and the like, and this is dispersed in a dispersion (in some cases, redispersion may be necessary). And can be used for coating according to the present invention.

  In preparing the fine particle dispersion, the above method may be used alone, or a plurality of methods may be used in combination (also referred to as combined). Moreover, a conventionally known reprecipitation method (for example, a method described in Chemistry and Industry, page 137, 2002) or the like may be applied as a method for preparing the nanoparticles.

(Measuring method of average particle diameter and average particle diameter of dispersed particles in fine particle dispersion)
By using these methods, it is possible to produce a fine particle dispersion containing nanoparticles having a nano-sized particle diameter, which is effective when the constituent layers of the organic EL device of the present invention are laminated by coating, and The characteristics (luminance, light emission lifetime, etc.) of the obtained device are also extremely good.

  Here, the average particle size of the dispersed particles in the fine particle dispersion used in the present invention is preferably in the range of 1 nm to 200 nm, more preferably in the range of 5 nm to 100 nm, and particularly preferably in the range of 10 nm to 60 nm. is there.

  By appropriately selecting or combining them according to the material using the above-described method, a nanoparticle dispersion liquid suitable for forming a constituent layer of an organic EL element can be prepared. The particle size of the fine particles in the dispersion was measured with a Zetasizer 1000HS manufactured by Malvern. The concentration of the dispersion may be appropriately adjusted with the same solvent as that used for the dispersion solvent depending on the use conditions.

(Concentration of dispersion)
In the fine particle dispersion (which may be simply a dispersion), the concentration in the dispersion was measured by calculating the solid concentration by the method described later, and this value was taken as the concentration of the dispersion.

  Here, the solid content concentration was determined as follows. 5 g of the dispersion was weighed and dried under reduced pressure at 100 ° C. for 3 hours, and the mass of the residue was measured. At this time, the concentration of the dispersion (solid content concentration) was determined using the following general formula.

Solid content concentration (%) = residue mass (g) / 5 (g) × 100
<< Application of fine particle dispersion to formation of constituent layer of organic EL element >>
Regarding the application of the coating method to the formation of the constituent layers of the organic EL device according to the present invention (the constituent layers are an anode, a cathode, an organic layer, etc.) and the use of the dispersion during coating, the constituent layers are particularly limited. However, from the viewpoint of preferably obtaining the effects described in the present invention, such as improving the external quantum efficiency of the organic EL element, increasing the light emission lifetime, reducing the drive voltage, etc. Using the phosphorescent light-emitting material according to the invention (the phosphorescent light-emitting material will be described in detail later) as a fine particle dispersion (may be a fine particle dispersion), the light emitting layer of the organic EL device of the present invention is formed. The phosphorescent light emitting material is preferably incorporated in the light emitting layer as a dopant compound.

(Fine particle dispersion of phosphorescent organometallic complex)
As the phosphorescent light-emitting material according to the present invention, a phosphorescent organic metal complex is preferably used. Regarding the merit of incorporating a dopant into a light emitting layer by using a phosphorescent organic metal complex (a phosphorescent organic metal complex will be described in detail later) as a fine particle dispersion when forming a light emitting layer, the present inventors Thinks as follows.

  Conventionally, when a component layer of an element is formed using an organometallic complex (phosphorescent organometallic complex is also in this category) as an element material, methods such as vapor deposition (sputtering, etc.) or coating using a solution have been used. It has been used.

  Compared with the vapor deposition method, especially in view of the application in solution system, which is superior in cost merit, conventionally, in order to dissolve the organometallic complex, a polar solvent is generally used in the trader. It was the target.

  However, by using a polar solvent in which the organometallic complex is easy to dissolve, among the conventional organic EL device materials, it is said that the effect of suppressing concentration quenching is high, and an inclusion type organometallic complex or dendrimer structure In the case of a luminescent compound having an organic group, an organometallic complex having a ligand containing a polymer chain, etc., the original concentration quenching function is not sufficiently exhibited.

  Therefore, rather than dissolving the organometallic complex, by using it as a fine particle dispersion (fine particle dispersion), an inclusion type organometallic complex or an organometallic complex having a ligand containing a polymer chain is inherently produced. The present inventors have found that the concentration quenching suppression function possessed is sufficiently exhibited.

  Furthermore, when an organometallic complex is not used as a solution but as a fine particle dispersion (partial particle dispersion), optimization (tuning) adjustment for individual materials can be performed by changing the average particle diameter and dispersion concentration, and the thin film The merit in manufacturing the organic EL element that the physical properties can be controlled was also obtained.

  In addition, dispersion systems can have intermolecular interactions in the micro range compared to homogeneous solution systems, which makes it easy to optimize (tune) thin film properties for individual materials. The effect of the present invention was obtained.

  Further, the solvent for dispersing the phosphorescent organic metal complex in fine particles is not particularly limited as long as it is a dispersible solvent. However, in order to obtain the effects described in the present invention to the maximum, it is generally a poor solvent. It is preferable to use a nonpolar solvent, alcohol, water, or the like that is considered as a dispersion solvent.

《Composite》
The phosphorescent organometallic complex (which will be described in detail later) contained in the fine particle dispersion (which may be a fine particle dispersion) contains the phosphorescent organometallic complex. It may be included in the contact compound to form a complex.

  The complex is preferably present in a state in which a clathrate is encapsulated with a phosphorescent organometallic complex (also referred to as a light-emitting dopant, which will be described later). The inclusion compound preferably has a hole transporting group or an electron transporting group. The hole transporting group and the electron transporting group will be described in the case of an inclusion compound.

  Furthermore, the clathrate compound can be used in the form of a polymer having a partial structure having an clathrate function as a repeating unit.

  The inventors of the present invention achieved the above problems by improving the external extraction quantum efficiency and emission lifetime of the element, reducing the driving voltage, etc. by the organic EL element produced using the composite of the present invention. The background is shown below.

  A conventionally known light-emitting compound having a dendrimer structure (here, a dendrimer has a dendron (also called a dendritic molecule) in its molecule) and an organic fluorescent dye included in a cyclodextrin derivative. In an organic light-emitting device using a fluorescent color conversion film having a fluorinated organic fluorescent dye or an organic electroluminescence device characterized by containing an inclusion complex of an organic compound and a cyclodextrin, each luminescent compound is encapsulated. Inclusion effect due to inclusion in the internal space of the contact compound (also known as wrinkle effect, suppression of concentration quenching due to steric factors preventing access to dopants, prevention of material degradation, device stability Improvement) etc., but on the other hand, the efficiency of recombination of holes and electrons, which is indispensable for light emission of organic EL elements, is reduced. Smooth energy transfer from the excited triplet state of the host compound formed by recombination of holes and electrons to the phosphorescent compound (organometallic complex) is suppressed, and it is preferable that the luminous efficiency is decreased and the driving voltage is increased. There was a tendency for a new phenomenon to be invited.

  As a result of various studies, the present inventors consider that the adjustment of the balance between the inclusion effect and the charge injection is the key to solving the above-mentioned problem, and as a means for adjusting the balance, the molecules between the inclusion compound and the organometallic complex are intermolecular. Focusing on the action (here, the intermolecular interaction indicates the degree of inclusion of the organometallic complex by the inclusion compound).

  And, as a parameter representing the strength of the intermolecular interaction, the degree of inhibition of concentration quenching of each of the organometallic complex and the complex (in the present invention, the concentration indicating concentration quenching is calculated from the fluorescence intensity measurement. It is possible to estimate the state of balance between the clathrate effect and the charge injection by measuring the clathrate compound, which will be described in detail below.

  In addition to various display devices and displays, the composite according to the present invention is used as a material for forming various types of light sources, lighting devices, home lighting, interior lighting, and exposure light sources. It is also useful as a material, and is also useful as a forming material for a display device such as a backlight of a liquid crystal display device. Among them, it is preferably used as a material for forming an organic EL element used in the above display device and lighting device. In particular, as a material for forming a light emitting layer (details of the light emitting layer will be described later) which are constituent layers of the organic EL element. Preferably used.

  In the synthesis of the complex, the clathrate compound is clathrated with the phosphorescent organometallic complex, but a conventionally known clathrate (the clathrate compound has a guest molecule in the internal space of the clathrate compound). The complex of the present invention can be synthesized by referring to the synthesis methods (in the incorporated state) (these synthesis methods are well known to those skilled in the art).

<< inclusion compound >>
The clathrate compound used in the present invention will be described.

  The inclusion compound used in the present invention is a compound having an inclusion function as shown below.

(Inclusion)
The inclusion used in the present invention is a bond such as ionic bond force, ion-dipole interaction, hydrogen bond, charge transfer interaction, coordination bond, van der Waals force, π-π interaction (π stack), etc. The phenomenon in which the inclusion compound is encapsulated by force (in the present invention, the compound in which the phosphorescent organic metal complex is included) is surrounded, and the complex of the present invention is formed.

  In the present invention, the state in which the inclusion compound surrounds the guest molecule is a state in which the guest compound is completely or partially taken into the internal space of the inclusion compound. Including a case where a molecular assembly is formed by the intermolecular interaction, and a state where the guest compound is not completely taken into the internal space of the inclusion compound is included. In the present invention, the effect described in the present invention (improvement of external extraction quantum efficiency) can be more preferably obtained when the guest compound molecules are not completely taken into the internal space of the clathrate compound.

(Method of confirming inclusion)
As a method for confirming whether the phosphorescent organometallic complex according to the present invention is included in a clathrate compound to form a complex or is present in an uninclusion body state, a conventionally known clathrate is used. General body confirmation methods can be used.

  For example, by performing inclusion in a solvent system in which the clathrate compound dissolves but the organometallic complex does not dissolve, the formation of the clathrate can be confirmed with the disappearance of the organometallic complex in the solution.

As a more quantitative confirmation means, by using ¹ H-NMR (nuclear magnetic resonance analysis) or ¹³ C-NMR (nuclear magnetic resonance analysis), etc. It can be quantitatively confirmed whether or not a complex is formed with the compound.

  The balance between the inclusion effect and the charge injection, that is, the magnitude of the intermolecular interaction between the inclusion compound and the organometallic complex is calculated by calculating the degree of inhibition of concentration quenching, which will be described in detail below. (Also called the degree of concentration quenching suppression) can be confirmed.

  Hereinafter, the degree of inclusion will be described.

《Calculation method of degree of inclusion (inhibition level of concentration quenching)》
As a method of calculating the degree of inclusion, the concentration of concentration quenching is measured from the fluorescence intensity measurement of the complex of the present invention and the organometallic complex in an uninclusion state, and the degree of suppression of concentration quenching is calculated. The degree of was estimated.

  Specifically, it can be calculated by the following operation. The synthesized complex (also referred to as clathrate) was purified by gel filtration chromatography, column chromatography, or the like, then fluorescence was measured at different concentrations (N = 3 for each measurement), and the average value was used. .

  The concentration [C] indicating concentration quenching was determined from the fluorescence intensity at each concentration. Similarly, the concentration [C0] indicating concentration quenching of the organometallic complex of the non-inclusion body serving as a blank is determined, and when the relationship between the two is (C / C0)> 1.1, the inclusion body (organic Metal complex is included by the inclusion compound). Here, in this invention, it is preferable that the value of (C / C0) is 1.2 or more, More preferably, it is the range of 1.4-3.0.

  The concentration of the phosphorescent dopant in the clathrate can be determined and calculated by ICP (inductively coupled plasma) emission analysis, which is a well-known inorganic metal quantitative method.

  From the above, the present inventors considered the balance between the inclusion effect and the charge injection by considering the intermolecular interaction between the inclusion compound and the organometallic complex from the above-mentioned inclusion degree (concentration quenching suppression degree). And an organic EL device having a long light emission lifetime has been developed while taking advantage of the high light emission efficiency of the phosphorescent organic EL device. Moreover, it turned out that the organic EL element of this invention shows the outstanding characteristic that a drive voltage is also low.

  In addition, as one method for controlling the inclusion state of the organometallic complex in a complex formed by an inclusion compound and a phosphorescent organometallic complex that is clathrated with the inclusion compound, And a phosphorescent dopant combination, for example, a clathrate and an organometallic complex (phosphorescent dopant) at the time of clathration, such as 1: 1 clathrate and 2: 1 clathrate The inclusion ratio with can be adjusted. As described above, as a result of the control of the inclusion state (specifically, the balance adjustment between the inclusion effect and the intermolecular interaction), the external extraction quantum efficiency and In addition to improving the light emission lifetime, the effect of reducing the driving voltage of the element can also be realized.

《Specific examples of inclusion compounds》
The inclusion compound used in the present invention refers to a compound having the inclusion function shown below, for example, crown ether derivative, cyclophane derivative, calixarene derivative, carbon nanotube derivative, cyclodextrin derivative, cyclotriphosphazene derivative. , Cryptand derivatives, potando derivatives and the like, among which calixarene derivatives, crown ether derivatives and cyclodextrin derivatives are preferred, and calixarene derivatives and crown ether derivatives are more preferred.

  Further, calixarene derivatives, crown ether derivatives, and cyclodextrin derivatives that are preferably used as clathrate compounds used in the present invention will be specifically described below.

(Calixarene derivative)
The calixarene derivative used in the present invention is, as represented by the following general formula (A), a phenol derivative represented by an alkylene group or an oxyalkylene group (wherein the oxyalkylene group is the terminal of the following alkylene group or Represents a group in which at least one of the carbon atoms constituting the alkylene group is substituted with an oxygen atom.), And the phenolic hydroxyl group in the molecule is substituted with a substituent. It doesn't matter.

  In the general formula (A), the divalent linking groups represented by A and L are each an alkylene group (for example, ethylene group, trimethylene group, tetramethylene group, propylene group, ethylethylene group, pentamethylene group, Hexamethylene group, 2,2,4-trimethylhexamethylene group, heptamethylene group, octamethylene group, nonamethylene group, decamethylene group, undecamethylene group, dodecamethylene group, cyclohexylene group (for example, 1,6-cyclohexanediyl) Group), alkenylene group (eg, propenylene group, vinylene group (also referred to as ethynylene group), 4-propyl-2-pentenylene group, etc.), alkynylene group (eg, ethynylene group, 3-pentynylene group, etc.), arylene group ( For example, o-phenylene group, m-phenylene group, p-phenylene group, Talenediyl group, anthracenediyl group, naphthacenediyl group, pyrenediyl group, naphthylnaphthalenediyl group, biphenyldiyl group (for example, 3,3′-biphenyldiyl group, 3,6-biphenyldiyl group, etc.), terphenyldiyl group, quater In addition to hydrocarbon groups such as phenyldiyl group, kinkphenyldiyl group, sexiphenyldiyl group, septiphenyldiyl group, octiphenyldiyl group, nobiphenyldiyl group, deciphenyldiyl group, etc., the alkylene group, Each of the alkenylene group, the alkynylene group, and the arylene group may contain a heteroatom (for example, a nitrogen atom, a sulfur atom, a silicon atom, etc.), or may be a thiophene-2,5-diyl group or a pyrazine. Compounds having an aromatic heterocycle such as a -2,3-diyl group A divalent linking group derived from a heteroaromatic compound) or a chalcogen atom such as oxygen or sulfur, or an alkylimino group, dialkylsilanediyl group or diarylgermandiyl group. Or a group in which heteroatoms are linked together.

  Furthermore, examples of the divalent linking group represented by A and L include, for example, a carbazole ring, a carboline ring, a diazacarbazole ring (also referred to as a monoazacarboline ring, and one of the carbon atoms constituting the carboline ring is a nitrogen atom) The aromatic structure such as triazole ring, pyrrole ring, pyridine ring, pyrazine ring, quinoxaline ring, thiophene ring, oxadiazole ring, dibenzofuran ring, dibenzothiophene ring, indole ring, etc. A divalent group derived from an aromatic heterocyclic ring selected from a ring group can be used.

  Furthermore, you may have a substituent represented by R mentioned later.

  In the general formula (A), the substituent represented by R is an alkyl group (for example, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, octyl group, dodecyl group). , Tridecyl group, tetradecyl group, pentadecyl group etc.), cycloalkyl group (eg cyclopentyl group, cyclohexyl group etc.), alkenyl group (eg vinyl group, allyl group etc.), alkynyl group (eg ethynyl group, propargyl group etc.) ), Aryl groups (for example, phenyl group, naphthyl group, etc.), aromatic heterocyclic groups (for example, furyl group, thienyl group, pyridyl group, pyridazinyl group, pyrimidinyl group, pyrazinyl group, triazinyl group, imidazolyl group, pyrazolyl group, Thiazolyl, quinazolinyl, carbazolyl, carbolinyl, dia A carbazolyl group (indicating that one of the carbon atoms constituting the carboline ring of the carbolinyl group is replaced by a nitrogen atom), a phthalazinyl group, etc., a heterocyclic group (eg, pyrrolidyl group, imidazolidyl group, morpholyl group, oxazolidyl group) Group), alkoxy group (for example, methoxy group, ethoxy group, propyloxy group, pentyloxy group, hexyloxy group, octyloxy group, dodecyloxy group, etc.), cycloalkoxy group (for example, cyclopentyloxy group, cyclohexyloxy group) Etc.), aryloxy groups (eg phenoxy group, naphthyloxy group etc.), alkylthio groups (eg methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group etc.), cycloalkylthio group ( Example For example, cyclopentylthio group, cyclohexylthio group, etc.), arylthio group (eg, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group) , Dodecyloxycarbonyl group etc.), aryloxycarbonyl group (eg phenyloxycarbonyl group, naphthyloxycarbonyl group etc.), sulfamoyl group (eg aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group) Hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminos Sulfonyl group, 2-pyridylaminosulfonyl group, etc.), acyl group (for example, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenyl) Carbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group (eg, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide Groups (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexyl group) Rubonylamino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc.), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl) Group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc. ), Ureido groups (eg, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido) , Dodecylureido group, phenylureido group, naphthylureido group, 2-pyridylaminoureido group, etc.), sulfinyl group (for example, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group) , Phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group, etc.), alkylsulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc.) Arylsulfonyl group or heteroarylsulfonyl group (for example, phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), Mino group (for example, amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, naphthylamino group, 2-pyridylamino group), halogen atom (For example, fluorine atom, chlorine atom, bromine atom, etc.), fluorinated hydrocarbon group (for example, fluoromethyl group, trifluoromethyl group, pentafluoroethyl group, pentafluorophenyl group, etc.), cyano group, nitro group, hydroxy Group, mercapto group, silyl group (for example, trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group, phenyldiethylsilyl group, etc.).

  These substituents may be further substituted with the above substituents. In addition, a plurality of these substituents may be bonded to each other to form a ring.

  Specific examples of the calixarene derivative used in the present invention are listed below, but the present invention is not limited to these.

  In CA-1, A represents CH or N, R represents a hydrogen atom, a methyl group, or an acetyl group, and n represents an integer of 1 to 6.

(Crown ether derivative)
The crown ether derivative used in the present invention is a cyclic polyether as represented by the following general formula (B) or general formula (C), in which the entire ring becomes a polydentate ligand, and metal ions And a general term for compounds having a function of clathrating with organic ions, and some or all of them may be substituted with nitrogen or sulfur instead of oxygen atoms.

  In each of the general formula (B) and general formula (C), L represents a single bond or a divalent linking group, and Ch represents an oxygen atom or a sulfur atom. m represents an integer of 1 to 9, n represents an integer of 1 to 3, and Z represents a residue of a fluorescent compound or a residue of a phosphorescent compound.

  In each of the general formula (B) and general formula (C), the divalent linking group represented by L has the same meaning as the divalent linking group represented by A and L in the general formula (A). is there.

  In each of the general formula (B) and general formula (C), the fluorescent compound used as the residue of the fluorescent compound represented by Z is described in a fluorescent dopant (also referred to as a fluorescent compound) described later. Specific examples of the dye, the fluorescent compound, or the fluorescent dopant are given.

  In each of the general formula (B) and general formula (C), the phosphorescent compound used as the residue of the phosphorescent compound represented by Z is a phosphorescent compound (also referred to as a phosphorescent dopant) described later. And the like.

  Moreover, the crown ether derivative represented by each of the general formulas (B) and (C) may have a substituent R included in the calixarene derivative represented by the general formula (A).

  Specific examples of the crown ether derivative used in the present invention are listed below, but the present invention is not limited to these.

  In each of CE-1 and CE-2, which are the specific examples described above, A represents CH or N, and n represents an integer of 1 to 9.

(Cyclodextrin derivative)
The cyclodextrin derivative used in the present invention is a general term for compounds having a structure in which a plurality of D-glucopyranose groups are cyclized by α-1,4 glycosidic bonds as represented by the following general formula (D). The primary and secondary hydroxyl groups present in the molecule may be substituted with a substituent.

  In the general formula (D), R represents a substituent, and Z represents a residue of a fluorescent compound or a phosphorescent compound.

  In the general formula (D), the substituent represented by R has the same meaning as the substituent represented by R in the general formula (A).

  In the general formula (D), examples of the fluorescent compound used as a residue of the fluorescent compound represented by Z include a dye, a fluorescent compound, or a fluorescent compound described in a fluorescent dopant (also referred to as a fluorescent compound) described later. Specific examples of the ionic dopant are listed.

  In the general formula (D), examples of the phosphorescent compound used as a residue of the phosphorescent compound represented by Z include the compounds described in the phosphorescent compound (also referred to as phosphorescent dopant) described later. .

  Hereinafter, although the preferable specific example of the cyclodextrin derivative used for this invention is shown, this invention is not limited to these.

  In CD-1 and 2, Ac represents an acetyl group.

  In addition, the clathrate compound used in the present invention is at least a hole transporting group or an electron transporting group (wherein the electron transporting group is derived from an electron transporting material described later) from the viewpoint of improving the luminous efficiency of the device. And the like are preferably used.

(Hole transporting group possessed by the inclusion compound)
The hole transporting group possessed by the clathrate compound used in the present invention will be described.

  The hole transporting group possessed by the clathrate compound used in the present invention is derived from a hole transporting material contained in a hole transporting layer used as a constituent layer of the organic EL device of the present invention described later. Substituents are preferably used.

  The hole transport material containing the substituent (hole transportable group) as a partial structure in the molecule has either hole injection or transport or electron barrier property, and is either organic or inorganic. For example, a triazole derivative, an oxadiazole derivative, an imidazole derivative, a carbazole derivative, a carboline derivative, a diazacarbazole derivative (here, diazacarbazole is a carbon constituting a carboline ring of the carboline derivative. One of the atoms is replaced by a nitrogen atom.), Polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazones Invitation , Stilbene derivatives, silazane derivatives, aniline-based copolymers, and conventionally known materials such as conductive polymer oligomers, particularly thiophene oligomers, porphyrin compounds, aromatic tertiary amine compounds and styrylamine compounds, aromatic And tertiary amine compounds.

  Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N, N ′, N′-tetraphenyl-4,4′-diaminophenyl; N, N′-diphenyl-N, N′— Bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (TPD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ′, N′-tetra-p-tolyl-4,4′-diaminobiphenyl; 1,1-bis (4-di-p-tolyl) Aminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p-tolylaminophenyl) phenylmethane; N, N'-diphenyl-N, N ' − (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadriphenyl; N, N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenylamino- (2-diphenylvinyl) benzene; 3-methoxy-4′-N, N-diphenylaminostilbenzene; N-phenylcarbazole, and two more described in US Pat. No. 5,061,569 Having a condensed aromatic ring of, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-308 4,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 88 are linked in a starburst type ( MTDATA) and the like.

  Hereinafter, an example of a method for preparing the fine particle dispersion used in the present invention is shown below.

(A) Preparation of fine particle dispersion by reprecipitation method 300 mg of polyvinylcarbazole (PVK) and 18 mg of tris (2-phenylpyridine) iridium (Ir (ppy) ₃ ) were dissolved in 30 ml of tetrahydrofuran (THF). Next, 50 ml of ethanol / THF (9/1) solution was vigorously stirred, and 10 ml of the above THF solution was added dropwise thereto using a microsyringe to obtain a primary dispersion. This primary dispersion was stirred and slowly concentrated under a nitrogen stream over about 6 hours until the volume was almost halved to obtain the desired dispersion (average particle size 60 nm).

(B) Preparation of Fine Particle Dispersion (Production of Nano Fine Particles) by Emulsification Dispersion In a pot of Creamix CLM (manufactured by M Technique Co., Ltd.), 12 g of polyvinylcarbazole (PVK) and tris (2-phenylpyridine) iridium (Ir (Ppy) ₃ ) 0.72 g and 1,2-dichloroethane 100 ml were added and dissolved by stirring.

  To this, 270 ml of pure water was added and emulsified at 20000 rpm for 5 minutes. Thereafter, 1,2-dichloroethane was washed away to obtain a fine particle aqueous dispersion (average particle size 40 nm).

  Next, the solvent was replaced with n-butyl alcohol in accordance with an ordinary method to obtain a desired fine particle alcohol dispersion (average particle size 50 nm).

(C) Method for producing nano-particle dispersion using apex mill 50 g of 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (α-NPD) is added to 300 ml of ethyl alcohol. Was dispersed with an apex mill manufactured by Sakai Kogyo Co., Ltd. using 0.05 mm beads for 20 minutes at a peripheral speed of 8 m / sec to obtain a desired fine particle alcohol dispersion (average particle size 35 nm).

<< Method for producing organic EL element >>
As an example of the method for producing the organic EL device of the present invention, a method for producing an organic EL device comprising an anode / anode buffer layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode. explain.

  First, a thin film made of a desired electrode material, for example, an anode material is formed on a suitable substrate by a method such as vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably 10 nm to 200 nm, thereby producing an anode. To do. Next, an organic compound thin film of an anode buffer layer, a hole transport layer, a light emitting layer, a hole blocking layer, an electron transport layer, and a cathode buffer layer, which are organic EL element materials, is formed thereon.

As a method for thinning the organic compound thin film, there are a vapor deposition method and a wet process (spin coating method, casting method, ink jet method, printing method) as described above. From the standpoint that holes are not easily generated, vacuum deposition, spin coating, ink jet, and printing are particularly preferable. Further, different film forming methods may be applied for each layer. When a vapor deposition method is employed for film formation, the vapor deposition conditions vary depending on the type of compound used, but generally a boat heating temperature of 50 ° C. to 450 ° C., a vacuum degree of 10 ⁻⁶ Pa to 10 ⁻² Pa, and a vapor deposition rate of 0 It is desirable to select appropriately within the range of 0.01 nm / second to 50 nm / second, substrate temperature −50 ° C. to 300 ° C., film thickness 0.1 nm to 5 μm, preferably 5 nm to 200 nm.

  After these layers are formed, a thin film made of a cathode material is formed thereon by a method such as vapor deposition or sputtering so as to have a thickness of 1 μm or less, preferably in the range of 50 to 200 nm, and a cathode is provided. Thus, a desired organic EL element can be obtained. The organic EL element is preferably produced from the hole injection layer to the cathode consistently by a single evacuation, but may be taken out halfway and subjected to different film forming methods. At that time, it is necessary to consider that the work is performed in a dry inert gas atmosphere.

  The multicolor display device of the present invention is provided with a shadow mask only when the light emitting layer is formed, and the other layers are common, so that patterning of the shadow mask or the like is unnecessary, and the evaporation method, the casting method, the spin coating method, the ink jet method on one side. A film can be formed by a method, a spray method, a printing method, or the like.

  When patterning is performed only on the light emitting layer, the method is not limited. However, a vapor deposition method, an inkjet method, and a printing method are preferable. In the case of using a vapor deposition method, patterning using a shadow mask is preferable.

  In addition, it is also possible to reverse the production order to produce a cathode, a cathode buffer layer, an electron transport layer, a hole transport layer, a light emitting layer, a hole transport layer, an anode buffer layer, and an anode in this order. When a DC voltage is applied to the multicolor display device thus obtained, light emission can be observed by applying a voltage of about 2 to 40 V with the positive polarity of the anode and the negative polarity of the cathode. An alternating voltage may be applied. The alternating current waveform to be applied may be arbitrary.

<< Constitutional layer of organic EL element, organic layer, inorganic compound layer >>
The constituent layer of the organic EL element of the present invention, the organic layer related to the constituent layer, and the inorganic compound layer will be described.

In this invention, although the preferable specific example of the layer structure of an organic EL element is shown below, this invention is not limited to these.
(I) Anode / light emitting layer / electron transport layer / cathode (ii) Anode / hole transport layer / light emitting layer / electron transport layer / cathode (iii) Anode / hole transport layer / light emitting layer / hole blocking layer / electron Transport layer / cathode (iv) anode / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode (v) anode / anode buffer layer / hole transport layer / light emitting layer / hole Blocking layer / electron transport layer / cathode buffer layer / cathode (organic layer)
Examples of the organic layer according to the organic EL device of the present invention include a hole transport layer, a light emitting layer, a hole blocking layer, an electron transport layer, and the like in the above-described layer configuration. If an organic compound contained in a constituent layer of an organic EL element such as an electron injection layer is contained, it is defined as an organic layer. Furthermore, when an organic compound is used for the anode buffer layer, the cathode buffer layer, etc., the anode buffer layer and the cathode buffer layer each form an organic layer.

  The organic layer includes a layer containing an “organic EL element material that can be used for a constituent layer of an organic EL element” described later.

(Inorganic compound layer)
The inorganic compound layer according to the organic EL element of the present invention forms a main component of an inorganic compound as a constituent component of the constituent layer (here, the main component indicates a case where 50% by mass or more of the entire layer is contained). Specifically, the case where an inorganic compound is used for formation of an anode buffer layer, a cathode buffer layer, etc. in the above-described layer configuration can be mentioned.

<< Tg (glass transition point) of three consecutive layers >>
The three constituent layers A, B and C constituting the three constituent layers or the four constituent layers of the organic layer according to the present invention are formed after the constituent layer A is formed, The constituent layer C is applied to form a continuous layer, and the constituent layer A is the main component A, the constituent layer B is the main component B, and the constituent layer C is the main component C. The glass transition point Tg-A of the main component A, the glass transition point Tg-B of the main component B, and the glass transition point Tg-C of the main component C satisfy the following inequality (1). It is mentioned as one of the preferable embodiments.

Inequality (1)
Tg-A>Tg-B> Tg-C
Here, the glass transition point (Tg) can be measured by a conventionally known DSC (Differential Scanning Colorimetry).

《Hole transport layer》
The hole transport layer is made of a hole transport material having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. The hole transport layer can be provided as a single layer or a plurality of layers.

  The hole transport material has any one of hole injection or transport and electron barrier properties, and may be either organic or inorganic.

  Examples of the hole transport layer used in the present invention include triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazoles. Conventionally known materials such as derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers, may be used.

  As the hole transport material, those described above can be used, but it is preferable to use a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound.

  Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N, N ′, N′-tetraphenyl-4,4′-diaminophenyl; N, N′-diphenyl-N, N′— Bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (TPD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ′, N′-tetra-p-tolyl-4,4′-diaminobiphenyl; 1,1-bis (4-di-p-tolyl) Aminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p-tolylaminophenyl) phenylmethane; N, N'-diphenyl-N, N ' − (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadriphenyl; N, N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenylamino- (2-diphenylvinyl) benzene; 3-methoxy-4′-N, N-diphenylaminostilbenzene; N-phenylcarbazole, and two more described in US Pat. No. 5,061,569 Having a condensed aromatic ring of, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-308 4,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (MTDATA) in which three triphenylamine units described in No. 88 are linked in a starburst type ) And the like.

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used. In addition, inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material.

  The hole transport layer can be formed by thinning the hole transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. it can. Although there is no restriction | limiting in particular about the film thickness of a positive hole transport layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5 nm-200 nm. This hole transport layer may have a single layer structure composed of one or more of the above materials.

  Hereinafter, although the specific example of the compound preferably used for formation of the positive hole transport layer of the organic EL element of this invention is given, this invention is not limited to these.

《Electron transport layer》
The electron transport layer used in the present invention is only required to have a function of transmitting electrons injected from the cathode to the light emitting layer, and as the material thereof, any one of conventionally known compounds is selected and used. be able to. The electron transport layer contains a material having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. The electron transport layer can be provided as a single layer or a plurality of layers.

  Examples of materials used for this electron transport layer (hereinafter referred to as electron transport materials) include heterocyclic tetracarboxylic acid anhydrides such as nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, naphthalene perylene, carbodiimides, Examples include fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, and oxadiazole derivatives. Furthermore, in the oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron-withdrawing group can also be used as an electron transport material. .

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

Or metal complexes of 8-quinolinol derivatives, such as tris (8-quinolinol) aluminum (Alq ₃ ), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) aluminum Tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), and the like, and the central metals of these metal complexes are In, Mg, Metal complexes replaced with Cu, Ca, Sn, Ga or Pb can also be used as the electron transport material.

  In addition, metal-free or metal phthalocyanine, and those having the terminal substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transporting material. Alternatively, the distyrylpyrazine derivative exemplified as the material for the light-emitting layer can also be used as an electron transport material, and, like the hole injection layer and the hole transport layer, inorganic such as n-type-Si and n-type-SiC A semiconductor can also be used as an electron transport material.

  The electron transport layer can be formed by forming the above compound by a known thin film forming method such as a vacuum deposition method, a spin coating method, a casting method, or an LB method.

(Film thickness of electron transport layer)
The electron transport layer can be formed by thinning the electron transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5 nm-200 nm. The electron transport layer may have a single layer structure composed of one or more of the above materials.

  Hereinafter, although the specific example of the compound preferably used for formation of the electron carrying layer of the organic EL element of this invention is given, this invention is not limited to these.

<Light emitting layer>
The light emitting layer used in the present invention will be described.

  The light emitting layer used in the present invention is a layer that emits light by recombination of electrons and holes injected from the electrode, the electron transport layer, or the hole transport layer, and the light emitting portion is in the layer of the light emitting layer. Alternatively, it may be the interface between the light emitting layer and the adjacent layer.

  For the light-emitting layer used in the present invention, the composite of the present invention (the above-mentioned clathrate compound is clathrated with the above organometallic complex (phosphorescent light-emitting dopant) that emits phosphorescence) is used. Thus, an organic EL element with high luminous efficiency and a long lifetime can be produced.

  There are two types of light emission of phosphorescent compounds in principle. One is the recombination of carriers on the host compound to which carriers are transported to generate an excited state of the host compound, and this energy is phosphorescent. An energy transfer type in which light emission from the phosphorescent compound is obtained by transferring to the compound, and the other is that the phosphorescent compound becomes a carrier trap, and carrier recombination occurs on the phosphorescent compound, and the phosphorescent compound In any case, the excited state energy of the phosphorescent compound is lower than the excited state energy of the host compound.

  In the present invention, the phosphorescent maximum wavelength of the phosphorescent compound is not particularly limited. In principle, the phosphorescent compound can be obtained by selecting a central metal, a ligand, a ligand substituent, and the like. However, it is preferable that the phosphorescent compound has a maximum phosphorescence emission wavelength of 380 nm to 480 nm.

  Examples of such phosphorescent emission wavelengths include organic EL elements that emit blue light and organic EL elements that emit white light. These elements should be operated with lower emission voltage and lower power consumption. Can do.

  In addition, by using a plurality of phosphorescent compounds, it is possible to mix different light emission, thereby obtaining an arbitrary emission color. White light emission is possible by adjusting the kind of phosphorescent compound and the amount of doping, and can also be applied to illumination and backlight.

《Host compound》
The host compound used in the present invention is a compound having a phosphorescence quantum yield of phosphorescence emission of less than 0.01 at room temperature (25 ° C.) among compounds contained in the light emitting layer.

  In the light emitting layer used in the present invention, a plurality of known host compounds may be used in combination as a host compound. By using a plurality of types of host compounds, it is possible to adjust the movement of charges, and the organic EL element can be made highly efficient. As these known host compounds, compounds having a hole transporting ability and an electron transporting ability, preventing the emission of longer wavelengths, and having a high Tg (glass transition temperature) are preferable.

  Specific examples of known host compounds include compounds described in the following documents.

  JP-A-2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645, 2002-338579, 2002-105445 gazette, 2002-343568 gazette, 2002-141173 gazette, 2002-352957 gazette, 2002-203683 gazette, 2002-363227 gazette, 2002-231453 gazette, No. 003-3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-286061, No. 2002-280183, No. 2002-299060, No. 2002. -302516, 2002-305083, 2002-305084, 2002-308837, and the like.

  Moreover, the light emitting layer may contain the host compound which has a fluorescence maximum wavelength further as a host compound. In this case, the energy transfer from the other host compound and the phosphorescent compound to the fluorescent compound allows electroluminescence as an organic EL element to be emitted from the other host compound having a fluorescence maximum wavelength. A host compound having a fluorescence maximum wavelength is preferably a compound having a high fluorescence quantum yield in a solution state. Here, the fluorescence quantum yield is preferably 10% or more, particularly preferably 30% or more. Specific host compounds having a maximum fluorescence wavelength include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, and pyrylium dyes. Perylene dyes, stilbene dyes, polythiophene dyes, and the like. The fluorescence quantum yield can be measured by the method described in 362 (1992, Maruzen) of Spectroscopic II of the Fourth Edition Experimental Chemistry Course 7.

  The color emitted in this specification is the spectral radiance meter CS-1000 (Minolta) in FIG. 4.16 on page 108 of “New Color Science Handbook” (Edited by the Japan Society for Color Science, University of Tokyo Press, 1985). It is determined by the color when the measured result is applied to the CIE chromaticity coordinates.

  The light emitting layer can be formed by forming the above compound by a known thinning method such as a vacuum deposition method, a spin coating method, a casting method, an LB method, or an ink jet method. Although the film thickness as a light emitting layer does not have a restriction | limiting in particular, Usually, 5 nm-5 micrometers, Preferably it is chosen in the range of 5 nm-200 nm. The light emitting layer may have a single layer structure in which these phosphorescent compounds and host compounds are composed of one or more kinds, or may have a laminated structure composed of a plurality of layers having the same composition or different compositions. Good.

  Hereinafter, although the specific example of the compound preferably used as a host compound of the light emitting layer of the organic EL element of this invention is given, this invention is not limited to these.

<< Phosphorescent compound (also called phosphorescent dopant, phosphorescent dopant, etc.) >>
The phosphorescent compound used in the present invention is preferably selected from the following organometallic complexes that exhibit phosphorescence emission (also referred to as phosphorescent compounds).

  For example, an iridium complex described in JP-A No. 2001-247859, represented by a formula as described in International Publication No. 00 / 70,655, pages 16 to 18, for example, tris (2-phenylpyridine) iridium Etc., platinum complexes such as osmium complexes or 2,3,7,8,12,13,17,18-octaethyl-21H, 23H-porphyrin platinum complexes. By using such a phosphorescent compound as a dopant, a light-emitting organic EL device with high internal quantum efficiency can be realized.

  The phosphorescent compound used in the present invention is preferably a complex compound containing any one metal belonging to Group 8, Group 9 or Group 10 of the periodic table, but more preferably Iridium compounds, osmium compounds, platinum compounds (platinum complex compounds), and rare earth complexes.

  In the phosphorescent compound (phosphorescent compound) used in the present invention, emission from an excited triplet is observed, and the phosphorescent quantum yield is preferably 0.001 or more at 25 ° C. More preferably, the phosphorescence quantum yield is 0.01 or more, and particularly preferably 0.1 or more.

  The phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of Experimental Chemistry Course 4 of the 4th edition. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence quantum yield should just be achieved in any solvent.

  Hereinafter, although the specific example of the compound preferably used as a phosphorescent compound (it is also called a phosphorescence emitting compound, a light emission dopant, etc.) of the light emitting layer of the organic EL element of this invention is given, this invention is not limited to these.

  Each of the above organometallic complexes may be used alone or in combination of two or more compounds. These compounds are described in, for example, Inorg. Chem. Reference can be made to the method described in Vol. 40, 1704 to 1711.

  As the phosphorescent compound (phosphorescent compound) of the present invention, a blue light-emitting orthometal complex as described below is preferably used as a so-called blue light-emitting dopant in which light emission from an excited triplet is blue.

  In addition, as the phosphorescent compound according to the present invention, a dendrimer-type phosphorescent organic metal complex represented by the following general formula (D1) can be used.

General formula (D1)
P-[(Dendron) m] n
In the general formula (D1), dendron represents a dendritic molecule represented by the following general formula (E), n represents an integer greater than 0, m represents an integer greater than 0 and less than n. To express. P represents a phosphorescent organometallic complex that serves as a core.

  General formula (E)

  In the general formula (E), Ar represents a trivalent group derived from an aromatic hydrocarbon ring or an aromatic heterocyclic ring. Represents an aromatic heterocycle, and X represents a single bond or a divalent linking group that binds to the phosphorescent organometallic complex P, which serves as the core. n represents the number of branches (also called the number of generations).

  In the general formula (E), the aromatic hydrocarbon ring represented by Ar includes a benzene ring, a biphenyl ring, a naphthalene ring, an azulene ring, an anthracene ring, a phenanthrene ring, a pyrene ring, a chrysene ring, a naphthacene ring, a triphenylene ring, o-terphenyl ring, m-terphenyl ring, p-terphenyl ring, acenaphthene ring, coronene ring, fluorene ring, fluoranthrene ring, naphthacene ring, pentacene ring, perylene ring, pentaphen ring, picene ring, pyrene ring, Examples include a pyranthrene ring and anthraanthrene ring. In addition, these rings may further have a substituent represented by R in the general formula (A).

  In the general formula (E), examples of the aromatic heterocycle represented by Ar include a furan ring, a thiophene ring, an oxazole ring, a pyrrole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, and a benzimidazole. Ring, oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indazole ring, indazole ring, benzimidazole ring, benzothiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, cinnoline ring, quinoline ring, isoquinoline Ring, phthalazine ring, naphthyridine ring, carbazole ring, carboline ring, diazacarbazole ring (showing a ring in which one of the carbon atoms of the hydrocarbon ring constituting the carboline ring is further substituted with a nitrogen atom).

  In addition, these rings may further have a substituent represented by R in the general formula (A).

  In the general formula (E), the divalent linking group represented by X has the same meaning as the divalent linking group represented by A in the general formula (A).

  Hereinafter, although the specific example of a dendrimer represented by general formula (D1) is shown, this invention is not limited to these.

  The phosphorescent compounds used in the present invention are described in, for example, Organic Letter, vol. 16, p 2579-2581 (2001), Inorganic Chemistry, Vol. 30, No. 8, 1685-1687 (1991), J. MoI. Am. Chem. Soc. , 123, 4304 (2001), Inorganic Chemistry, Vol. 40, No. 7, pages 1704-1711 (2001), Inorganic Chemistry, Vol. 41, No. 12, pages 3055-3066 (2002) , New Journal of Chemistry. 26, page 1171 (2002), and further by applying a method such as a reference described in these documents.

  In addition, for example, J. et al. Am. Chem. Soc. 123, 4304-4312 (2001), International Publication No. 00/70655 pamphlet, No. 02/15645 pamphlet, JP-A No. 2001-247859, No. 2001-345183, No. 2002-117978, 2002-170684, 2002-203678, 2002-235076, 2002-302671, 2002-324679, 2002-332291, 2002-332292, Examples include iridium complexes represented by the general formula described in JP 2002-338588 A, etc., iridium complexes exemplified as specific examples, iridium complexes represented by formula (IV) described in JP 2002-8860 A, and the like. It is done.

<< Fluorescent dopant (also called fluorescent compound) >>
In addition to the dopant made of a phosphorescent compound, the organic EL device of the present invention may further contain a fluorescent dopant. Typical examples of the fluorescent dopant include a coumarin dye and a pyran dye. Dye, cyanine dye, croconium dye, squalium dye, oxobenzanthracene dye, fluorescein dye, rhodamine dye, pyrylium dye, perylene dye, stilbene dye, polythiophene dye, or rare earth complex phosphor And other known fluorescent compounds.

  Hereinafter, although the preferable specific example of the fluorescent dopant used for this invention is given, this invention is not limited to these.

<Blocking layer: hole blocking layer, electron blocking layer>
The hole blocking layer is an electron transport layer in a broad sense, and is made of a material that has a function of transporting electrons and has a very small ability to transport holes. By blocking holes while transporting electrons, And the recombination probability of holes can be improved.

  The hole blocking layer has a role of blocking the holes moving from the hole transport layer from reaching the cathode and a compound that can efficiently transport the electrons injected from the cathode toward the light emitting layer. It is formed. The physical properties required of the material constituting the hole blocking layer are higher than the ionization potential of the light emitting layer in order to have high electron mobility and low hole mobility and to efficiently confine holes in the light emitting layer. It is preferable to have a value of ionization potential or a band gap larger than that of the light emitting layer. Use of at least one of styryl compounds, triazole derivatives, phenanthroline derivatives, oxadiazole derivatives, and boron derivatives as the hole blocking material is also effective in obtaining the effects of the present invention.

  Examples of other compounds include exemplified compounds described in JP-A Nos. 2003-31367, 2003-31368, and Japanese Patent No. 2721441.

  On the other hand, the electron blocking layer is a hole transport layer in a broad sense, made of a material that has a function of transporting holes and has a very small ability to transport electrons, and blocks electrons while transporting holes. Thus, the probability of recombination of electrons and holes can be improved.

  The hole blocking layer and the electron blocking layer can be formed by thinning the above material by a known method such as a vacuum deposition method, a spin coating method, a casting method, an ink jet method, or an LB method. .

"anode"
As the anode in the organic EL element, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such electrode materials include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ and ZnO. Alternatively, an amorphous material such as IDIXO (In ₂ O ₃ —ZnO) capable of forming a transparent conductive film may be used. For the anode, a thin film may be formed by depositing these electrode materials by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method. Degree), a pattern may be formed through a mask having a desired shape when the electrode material is deposited or sputtered. When light emission is extracted from the anode, it is desirable that the transmittance is greater than 10%, and the sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 nm to 1000 nm, preferably 10 nm to 200 nm.

"cathode"
On the other hand, as the cathode, a material having a low work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function value than this, such as a magnesium / silver mixture, magnesium, from the viewpoint of electron injectability and durability against oxidation, etc. / Aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred.

  The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance as a cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 nm to 200 nm. In order to transmit the emitted light, if either one of the anode or the cathode of the organic EL element is transparent or translucent, the emission luminance is advantageously improved.

  Moreover, after producing the said metal by the film thickness of 1 nm-20 nm to a cathode, the transparent or semi-transparent cathode can be produced by producing the electroconductive transparent material quoted by description of the anode on it, By applying this, an element in which both the anode and the cathode are transmissive can be manufactured.

<< Method for forming electrodes by coating >>
A method for forming electrodes (cathode, anode, etc.) according to the present invention will be described.

  The electrode is usually formed by sputtering ITO (Indium Tin Oxide) on a glass substrate or vacuum deposition of a metal such as aluminum or calcium, but the application according to the present invention (solution application, dispersion) As an electrode forming method by liquid application, etc., a method using a PEDOT derivative as an electrode (Japanese Patent Publication No. 2005-501373 and US Pat. No. 5,035,926), a method of applying a conductive paste and forming a circuit (special No. 2002-324966) is disclosed, and these methods can be used.

  Next, an injection layer, a blocking layer, an electron transport layer, and the like used as a constituent layer of the organic EL element of the present invention will be described.

<< Buffer layer >>: Anode buffer layer, cathode buffer layer An injection layer is provided as necessary, and includes a cathode buffer layer (electron injection layer) and an anode buffer layer (hole injection layer). You may exist between a positive hole transport layer and between a cathode and a light emitting layer or an electron carrying layer.

  The buffer layer is a layer that is provided between the electrode and the organic layer in order to lower the driving voltage and improve the light emission luminance. “The organic EL element and the forefront of its industrialization (November 30, 1998, issued by NTT Corporation) 2), Chapter 2, “Electrode Materials” (pages 123 to 166) in detail, and includes an anode buffer layer and a cathode buffer layer.

  The details of the anode buffer layer (hole injection layer) are described in JP-A Nos. 9-45479, 9-260062, and 8-288069. Specific examples thereof include copper phthalocyanine. Examples thereof include a phthalocyanine buffer layer, an oxide buffer layer typified by vanadium oxide, an amorphous carbon buffer layer, and a polymer buffer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene.

  Among the above, for example, an oxide buffer layer containing vanadium oxide as a main component is defined as the inorganic compound layer.

  The details of the cathode buffer layer (electron injection layer) are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specifically, strontium, aluminum, etc. A metal buffer layer typified by lithium fluoride, an alkali metal compound buffer layer typified by lithium fluoride, an alkaline earth metal compound buffer layer typified by magnesium fluoride, an oxide buffer layer typified by aluminum oxide, etc. . The buffer layer (injection layer) is preferably a very thin film, and the film thickness is preferably in the range of 0.1 nm to 5 μm, although it depends on the material.

  Among the above, for example, a metal buffer layer typified by strontium and aluminum, an alkali metal compound buffer layer typified by lithium fluoride, an alkaline earth metal compound buffer layer typified by magnesium fluoride, and aluminum oxide A representative oxide buffer layer or the like is an inorganic compound layer according to the present invention.

<< Substrate (also referred to as substrate, substrate, support, etc.) >>
The organic EL device of the present invention is preferably formed on a substrate.

  The substrate of the organic EL device of the present invention is not particularly limited to the type of glass, plastic, etc., and is not particularly limited as long as it is transparent. Examples of substrates that are preferably used include glass, quartz, A light transmissive resin film can be mentioned. A particularly preferable substrate is a resin film that can give flexibility to the organic EL element.

  Examples of the resin film include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyetherimide, polyetheretherketone, polyphenylene sulfide, polyarylate, polyimide, polycarbonate (PC), and cellulose triacetate. Examples thereof include films having (TAC), cellulose acetate propionate (CAP) and the like. In addition, an inorganic or organic film or a hybrid film of both may be formed on the surface of the resin film.

  The external extraction efficiency at room temperature for light emission of the organic electroluminescence device of the present invention is preferably 1% or more, more preferably 5% or more. Here, the external extraction quantum efficiency (%) = the number of photons emitted to the outside of the organic EL element / the number of electrons sent to the organic EL element × 100.

  In addition, a hue improvement filter such as a color filter may be used in combination, or a color conversion filter that converts the emission color from the organic EL element into multiple colors using a phosphor. In the case of using a color conversion filter, the λmax of light emission of the organic EL element is preferably 480 nm or less.

<< Organic EL element materials that can be used in the constituent layers of organic EL elements >>
Furthermore, the compound applicable as a constituent material of the structural layer of the organic EL element of this invention is demonstrated concretely. In addition, the compound shown below can be used for any layer of the organic layer according to the present invention as long as it does not affect the performance of the organic EL device of the present invention.

(Vinyl monomer)
As a vinyl monomer used for this invention, although the compound represented by following General formula (4) is mentioned, this invention is not limited to these.

  In the general formula (4), R represents a hydrogen atom or a methyl group, and A represents a divalent linking group or a single bond. Z represents a residue of a fluorescent compound or a phosphorescent compound residue (also referred to as a phosphorescent compound residue, which may have an organometallic complex in the molecular structure).

  In the general formula (4), examples of the divalent linking group represented by A include hydrocarbon groups such as an alkylene group, alkenylene group, alkynylene group, and arylene group, the alkylene group, the alkenylene group, and the alkynylene group. In the arylene group, each of them may contain a hetero atom (for example, a nitrogen atom, a sulfur atom, a silicon atom, etc.), or a thiophene-2,5-diyl group or pyrazine-2,3-diyl. It may be a divalent linking group derived from a compound having an aromatic heterocycle such as a group (also referred to as a heteroaromatic compound), or a chalcogen atom such as oxygen or sulfur. Further, it may be a group such as an alkylimino group, a dialkylsilanediyl group, or a diarylgermandiyl group that connects and connects heteroatoms.

  Furthermore, examples of the divalent linking group represented by A include, for example, a carbazole ring, a carboline ring, a diazacarbazole ring (also referred to as a monoazacarboline ring, and one of carbon atoms constituting the carboline ring is replaced by a nitrogen atom. From a group of aromatic heterocycles such as triazole ring, pyrrole ring, pyridine ring, pyrazine ring, quinoxaline ring, thiophene ring, oxadiazole ring, dibenzofuran ring, dibenzothiophene ring, indole ring, etc. A divalent group derived from a selected aromatic heterocycle can be used.

  Furthermore, in the said general formula (A), you may have a substituent represented by R.

  In the general formula (4), examples of the fluorescent compound used in the residue of the fluorescent compound include the compounds described in the above fluorescent dopant (also referred to as a fluorescent compound), rare earth complex phosphors, and other known fluorescent compounds. Compound.

  In the general formula (4), as the phosphorescent compound used for the phosphorescent compound residue, an organometallic complex described in the above phosphorescent compound, a compound described in a conventionally known document, or the like can be used. .

  Although the specific example of the vinyl monomer used for this invention below is shown, this invention is not limited to these.

(Vinyl polymer)
As the vinyl polymer used in the present invention, a compound having a repeating unit represented by the following general formula (5) can be used. The compound may be a homopolymer or a copolymer with other polymerizable monomers. It may be a polymer.

  In the general formula (5), R represents a hydrogen atom or a methyl group, and A represents a divalent linking group or a single bond. Z represents a residue of a fluorescent biocompound or a phosphorescent compound residue (also referred to as a phosphorescent compound residue, which may have an organometallic complex in the molecular structure).

  In the general formula (5), the divalent linking group represented by A has the same meaning as the divalent linking group represented by A in the general formula (4).

  In the general formula (5), the fluorescent compound residue and phosphorescent compound residue represented by Z are the fluorescent compound residue and phosphorescent group represented by Z in the general formula (4), respectively. Each is synonymous with a compound residue.

  Examples of the copolymerizable monomer (also referred to as a monomer) include, for example, methacrylic acid and ester derivatives thereof (methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, i-butyl methacrylate, methacrylic acid). t-butyl, octyl methacrylate, cyclohexyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, tetrahydrofurfuryl methacrylate, benzyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, etc.), or Acrylic acid and its ester derivatives (methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, i-butyl acrylate, t-butyl acrylate, octyl acrylate, acrylic acid Chlohexyl, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, 2-ethoxyethyl acrylate, diethylene glycol ethoxylate acrylate, 3-methoxybutyl acrylate, benzyl acrylate, dimethylamino acrylate Ethyl, diethylaminoethyl acrylate, etc.), alkyl vinyl ethers (methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether, etc.), alkyl vinyl esters (vinyl formate, vinyl acetate, vinyl butyrate, vinyl caproate, vinyl stearate, etc.), acrylonitrile, vinyl chloride And styrene.

  Although the specific example of the vinyl polymer used for this invention below is shown, this invention is not limited to these.

(Condensation polymer)
Examples of the condensation polymer used in the present invention include compounds represented by the following general formula (6), but the present invention is not limited thereto.

  In the general formula (6), [Ar] n represents an aromatic hydrocarbon ring or an aromatic heterocyclic ring having n substitutable sites. Z represents a fluorescent compound residue or a phosphorescent compound residue, and m of the n substitutable sites of Ar are linked via K. K represents a divalent linking group or a single bond. n represents a number from 1 to 3, and m represents a number from 1 to n. Here, when there are a plurality of Z and K, each may be independently the same or different. L is a divalent linking group selected from the linking group group 1 described below.

  In the general formula (6), the aromatic hydrocarbon ring represented by Ar includes a benzene ring, a biphenyl ring, a naphthalene ring, an azulene ring, an anthracene ring, a phenanthrene ring, a pyrene ring, a chrysene ring, a naphthacene ring, a triphenylene ring, o-terphenyl ring, m-terphenyl ring, p-terphenyl ring, acenaphthene ring, coronene ring, fluorene ring, fluoranthrene ring, naphthacene ring, pentacene ring, perylene ring, pentaphen ring, picene ring, pyrene ring, Examples include a pyranthrene ring and anthraanthrene ring. In addition, these rings may further have a substituent represented by R in the general formula (A).

  In the general formula (6), examples of the aromatic heterocycle represented by Ar include a furan ring, a thiophene ring, an oxazole ring, a pyrrole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, and a benzimidazole. Ring, oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indazole ring, indazole ring, benzimidazole ring, benzothiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, cinnoline ring, quinoline ring, isoquinoline Ring, phthalazine ring, naphthyridine ring, carbazole ring, carboline ring, diazacarbazole ring (showing a ring in which one of the carbon atoms of the hydrocarbon ring constituting the carboline ring is further substituted with a nitrogen atom).

  In addition, these rings may further have a substituent represented by R in the general formula (A).

  In the general formula (6), the divalent linking group represented by K has the same meaning as the divalent linking group represented by A in the general formula (4).

  In the general formula (6), the fluorescent compound residue and phosphorescent compound residue represented by Z are the fluorescent compound residue and phosphorescent group represented by Z in the general formula (4), respectively. Each is synonymous with a compound residue.

  In the general formula (6), the divalent linking group represented by L is selected from the following linking group group 1.

In the linking group group 1, R _{1 to} R ₄ each represents an alkyl group, an aromatic hydrocarbon group, or an aromatic heterocyclic group.

In the linking group group 1, examples of the alkyl group represented by R _{1 to} R ₄ include a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group, A dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, etc. are mentioned. These may further have a substituent represented by R in the general formula (A).

In the linking group group 1, examples of the aromatic hydrocarbon group represented by R _{1 to} R ₄ include a phenyl group, a p-chlorophenyl group, a mesityl group, a tolyl group, a xylyl group, a naphthyl group, an anthryl group, and an azulenyl group. Group, acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, biphenylyl group and the like.

  These groups may further have a substituent represented by R in the general formula (A).

In the linking group group 1, examples of the aromatic heterocyclic group represented by R _{1 to} R ₄ include a pyridyl group, a pyrimidinyl group, a furyl group, a pyrrolyl group, an imidazolyl group, a benzoimidazolyl group, a pyrazolyl group, a pyrazinyl group, Triazolyl group (for example, 1,2,4-triazol-1-yl group, 1,2,3-triazol-1-yl group, etc.), oxazolyl group, benzoxazolyl group, thiazolyl group, isoxazolyl group, isothiazolyl group , Flazanyl group, thienyl group, quinolyl group, benzofuryl group, dibenzofuryl group, benzothienyl group, dibenzothienyl group, indolyl group, carbazolyl group, carbolinyl group, diazacarbazolyl group (carbon constituting the carboline ring of the carbonyl group) One of the atoms replaced by a nitrogen atom), quinoxalinyl , Pyridazinyl group, triazinyl group, quinazolinyl group, and phthalazinyl group.

  These groups may further have a substituent represented by R in the general formula (A).

  Hereinafter, although the specific example of the condensation polymer represented by General formula (6) is shown, this invention is not limited to these.

<< Display device, lighting device >>
The display device (monochromatic or multicolored) and lighting device of the present invention will be described.

  The multicolor display device of the present invention is provided with a shadow mask only when the light emitting layer is formed, and the other layers are common, so that patterning of the shadow mask or the like is unnecessary, and the evaporation method, the casting method, the spin coating method, the ink jet method on one side. A film can be formed by a method, a spray method, a printing method, or the like.

  When patterning is performed only on the light emitting layer, the method is not limited. However, a vapor deposition method, an inkjet method, and a printing method are preferable. In the case of using a vapor deposition method, patterning using a shadow mask is preferable.

  In addition, it is also possible to reverse the production order to produce a cathode, a cathode buffer layer, an electron transport layer, a hole transport layer, a light emitting layer, a hole transport layer, an anode buffer layer, and an anode in this order. When a DC voltage is applied to the multicolor display device thus obtained, light emission can be observed by applying a voltage of about 2 to 40 V with the positive polarity of the anode and the negative polarity of the cathode. An alternating voltage may be applied. The alternating current waveform to be applied may be arbitrary.

  The display device of the present invention can be used as a display device, a display, and various light emission sources. In a display device or a display, full-color display is possible by using three types of organic EL elements of blue, red, and green light emission.

  Examples of the display device and display include a television, a personal computer, a mobile device, an AV device, a character broadcast display, and an information display in an automobile. In particular, it may be used as a display device for reproducing still images and moving images, and the driving method when used as a display device for reproducing moving images may be either a simple matrix (passive matrix) method or an active matrix method.

  The lighting device of the present invention includes home lighting, interior lighting, clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources of optical storage media, light sources of electrophotographic copying machines, light sources of optical communication processors, light sensors Although a light source etc. are mentioned, it is not limited to this.

  Further, the organic EL element according to the present invention may be used as an organic EL element having a resonator structure.

  Examples of the purpose of use of the organic EL element having such a resonator structure include a light source of an optical storage medium, a light source of an electrophotographic copying machine, a light source of an optical communication processing machine, and a light source of an optical sensor. It is not limited. Moreover, you may use for the said use by making a laser oscillation.

  The organic EL element of the present invention may be used as one kind of lamp for illumination or exposure light source, a projection device for projecting an image, or a display for directly viewing a still image or a moving image. It may be used as a device (display). When used as a display device for reproducing moving images, the driving method may be either a simple matrix (passive matrix) method or an active matrix method. Alternatively, a full-color display device can be manufactured by using three or more organic EL elements of the present invention having different emission colors. Alternatively, it is possible to make a single color emission color, for example, white emission, into BGR using a color filter to achieve full color. Further, it is possible to convert the emission color of the organic EL to another color by using a color conversion filter, and in this case, λmax of the organic EL emission is preferably 480 nm or less.

  An example of a display device having the organic EL element of the present invention as a configuration will be described with reference to the drawings.

  FIG. 1 is a schematic diagram illustrating an example of a display device including organic EL elements. It is a schematic diagram of a display such as a mobile phone that displays image information by light emission of an organic EL element.

  The display 1 includes a display unit A having a plurality of pixels, a control unit B that performs image scanning of the display unit A based on image information, and the like.

  The control unit B is electrically connected to the display unit A, and sends a scanning signal and an image data signal to each of the plurality of pixels based on image information from the outside. The pixels for each scanning line are converted into image data signals by the scanning signal. In response to this, light is sequentially emitted and image scanning is performed to display image information on the display unit A.

  FIG. 2 is a schematic diagram of the display unit A.

  The display unit A includes a wiring unit including a plurality of scanning lines 5 and data lines 6, a plurality of pixels 3 and the like on a substrate. The main members of the display unit A will be described below. FIG. 2 shows a case where the light emitted from the pixel 3 is extracted in the direction of the white arrow (downward).

  The scanning lines 5 and the plurality of data lines 6 in the wiring portion are each made of a conductive material, and the scanning lines 5 and the data lines 6 are orthogonal to each other in a grid pattern and are connected to the pixels 3 at orthogonal positions (details are shown in FIG. Not shown).

  When a scanning signal is applied from the scanning line 5, the pixel 3 receives an image data signal from the data line 6 and emits light according to the received image data. Full color display is possible by appropriately arranging pixels in the red region, the green region, and the blue region that emit light on the same substrate.

  Next, the light emission process of the pixel will be described.

  FIG. 3 shows a schematic diagram of a pixel.

  The pixel includes an organic EL element 10, a switching transistor 11, a driving transistor 12, a capacitor 13, and the like. A full color display can be performed by using red, green, and blue light emitting organic EL elements as the organic EL elements 10 in a plurality of pixels, and juxtaposing them on the same substrate.

  In FIG. 3, an image data signal is applied from the control unit B to the drain of the switching transistor 11 through the data line 6. When a scanning signal is applied from the control unit B to the gate of the switching transistor 11 via the scanning line 5, the driving of the switching transistor 11 is turned on, and the image data signal applied to the drain is supplied to the capacitor 13 and the driving transistor 12. Is transmitted to the gate.

  By transmitting the image data signal, the capacitor 13 is charged according to the potential of the image data signal, and the drive of the drive transistor 12 is turned on. The drive transistor 12 has a drain connected to the power supply line 7 and a source connected to the electrode of the organic EL element 10, and the power supply line 7 connects to the organic EL element 10 according to the potential of the image data signal applied to the gate. Current is supplied.

  When the scanning signal is moved to the next scanning line 5 by the sequential scanning of the control unit B, the driving of the switching transistor 11 is turned off. However, even if the driving of the switching transistor 11 is turned off, the capacitor 13 maintains the potential of the charged image data signal, so that the driving of the driving transistor 12 is kept on and the next scanning signal is applied. Until then, the light emission of the organic EL element 10 continues. When the scanning signal is next applied by sequential scanning, the driving transistor 12 is driven according to the potential of the next image data signal synchronized with the scanning signal, and the organic EL element 10 emits light.

  That is, the organic EL element 10 emits light by the switching transistor 11 and the driving transistor 12 that are active elements for the organic EL elements 10 of the plurality of pixels, and the organic EL elements 10 of the plurality of pixels 3 emit light. It is carried out. Such a light emitting method is called an active matrix method.

  Here, the light emission of the organic EL element 10 may be light emission of a plurality of gradations by a multi-value image data signal having a plurality of gradation potentials, or on / off of a predetermined light emission amount by a binary image data signal. But you can.

  The potential of the capacitor 13 may be held continuously until the next scanning signal is applied, or may be discharged immediately before the next scanning signal is applied.

  In the present invention, not only the active matrix method described above, but also a passive matrix light emission drive in which the organic EL element emits light according to the data signal only when the scanning signal is scanned.

  FIG. 4 is a schematic view of a passive matrix display device. In FIG. 4, a plurality of scanning lines 5 and a plurality of image data lines 6 are provided in a lattice shape so as to face each other with the pixel 3 interposed therebetween.

  When the scanning signal of the scanning line 5 is applied by sequential scanning, the pixels 3 connected to the applied scanning line 5 emit light according to the image data signal. In the passive matrix system, the pixel 3 has no active element, and the manufacturing cost can be reduced.

  The organic EL element material of the present invention can also be applied to an organic EL element that emits substantially white light as a lighting device. A plurality of light emitting colors are simultaneously emitted by a plurality of light emitting materials to obtain white light emission by color mixing. The combination of a plurality of emission colors may include three emission maximum wavelengths of three primary colors of blue, green, and blue, or two using a complementary color relationship such as blue and yellow, blue green and orange, etc. The thing containing the light emission maximum wavelength may be used.

  In addition, a combination of light emitting materials for obtaining a plurality of emission colors includes a combination of a plurality of phosphorescent or fluorescent materials (light emitting dopants), a light emitting material that emits fluorescent or phosphorescent light, and the light emission. Any combination of a dye material that emits light from the material as excitation light may be used, but in the white organic electroluminescence device according to the present invention, a method of combining a plurality of light-emitting dopants is preferable.

  As a layer structure of an organic electroluminescence device for obtaining a plurality of emission colors, a method of having a plurality of emission dopants in one emission layer, a plurality of emission layers, and an emission wavelength in each emission layer And a method of forming minute pixels emitting light having different wavelengths in a matrix.

  In the white organic electroluminescence device according to the present invention, patterning may be performed by a metal mask, an ink jet printing method, or the like at the time of film formation, if necessary. When patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire element layer may be patterned.

  The light emitting material used for the light emitting layer is not particularly limited. For example, in the case of a backlight in a liquid crystal display element, the platinum complex according to the present invention is known so as to be suitable for the wavelength range corresponding to the CF (color filter) characteristics. Any one of the light emitting materials may be selected and combined to be whitened.

  Thus, in addition to the display device and display, the white light-emitting organic EL element of the present invention can be used as a kind of lamp such as a home lighting, an interior lighting, and an exposure light source as various light emitting light sources and lighting devices. It is also useful for display devices such as backlights of liquid crystal display devices.

  Others such as backlights for watches, signboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, light sources for optical sensors, etc. There are a wide range of uses such as household appliances.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these. The structural formulas of the compounds used in the examples are shown below.

Example 1
<< Preparation of Organic EL Element 1-1 >>: Configuration of the Element of the Present Invention Cathode: Al
Cathode buffer layer (deposition): LiF
Electron transport layer (solution coating): BAlq
Mixed region (formation of a region having a continuous concentration gradient between the electron transport layer and the light-emitting layer)
Electron transport function: BAlq
Light emitting function: PVK + PD-1 (Ir (ppy) ₃ )
Light emitting layer (solution application): PVK + PD-1 (Ir (ppy) ₃ )
Hole transport layer (water dispersion coating): PEDOT / PSS
Anode: ITO
In the formation of the light emitting layer and the electron transport layer of the glass substrate element, after the lower layer (light emitting layer) is formed, a heat drying treatment is performed also as a smoothing treatment. Thereafter, the upper layer (electron transport layer) is coated and formed with a mixed solvent partially containing a solvent (solvent within the solubility parameter range) that dissolves the lower layer (light-emitting layer), whereby the electron transport layer and the light-emitting layer are formed. A mixed region having a continuous concentration gradient was formed between the two.

  After patterning on a substrate (NA-45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 100 nm of ITO (indium tin oxide) on a 100 mm × 100 mm × 1.1 mm glass substrate as an anode, this ITO transparent electrode was provided. The transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  On this transparent support substrate, a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water at 3000 rpm for 30 seconds. After forming the film by spin coating, the film was dried at 200 ° C. for 1 hour to provide a hole transport layer having a thickness of 30 nm. The substrate provided with the hole transport layer was transferred to a glove box substituted with nitrogen gas, and the subsequent operations were performed in the glove box.

On the hole transport layer, a solution prepared by dissolving 30 mg of polyvinyl N-carbazole (PVK; VP-6) and 1.5 mg of PD-1 (Ir (ppy) ₃ ) in 3 ml of dichlorobenzene at 1000 rpm for 30 seconds. Under the conditions, a film was formed by a spin coating method and vacuum-dried at 60 ° C. for 1 hour to obtain a light emitting layer having a thickness of 100 nm. A BAlq solution is obtained by dissolving 30 mg of bis (2-methyl-8-quinolate) -p-phenylphenolate aluminum complex (BAlq) in 2 ml of tetrahydrofuran, slowly adding 4 ml of hot toluene, and then slowly returning to room temperature. Adjusted. On the other hand, cold nitrogen gas (liquid nitrogen vaporization gas) was blown onto the light-emitting layer that had been sufficiently cooled in advance, and the BAlq solution was formed by spin coating at 1000 rpm for 30 seconds at 100 ° C. for 1 hour. It vacuum-dried and was set as the 50-nm-thick electron carrying layer.

  During the formation of the electron transport layer, a mixed region was formed between the electron transport layer and the light emitting layer. The film thickness of the mixed region was 30 nm from the concentration gradient analysis shown below.

This is attached to a vacuum deposition apparatus, then the vacuum chamber is decompressed to 4 × 10 ⁻⁴ Pa, lithium fluoride 0.5 nm is deposited as a cathode buffer layer and aluminum 110 nm is deposited as a cathode to form a cathode, and an organic EL device 1-1 was produced.

<< Concentration gradient analysis of mixed region (target elements: Al, Ir) >>
In the analysis of the concentration gradient in the mixed region of the organic EL element 1-1, aluminum and iridium were selected as target elements, and elemental analysis in the depth direction in the mixed region was performed.

  First, the concentration distribution of the depth direction of aluminum was measured for the element 1 formed up to the electron transport layer in the same manner as the organic EL element 1-1 using secondary ion mass spectrometry.

  From the upper surface of the electron transport layer to 40 nm, a substantially constant concentration was exhibited. This 40 nm indicates the film thickness of the electron transport layer. Next, after a rapid decrease in concentration from 40 nm to 65 nm, aluminum was not detected in the vicinity of 70 nm. Therefore, it can be seen that 30 nm from 40 nm to 70 nm is the thickness of the mixed region in the depth direction.

  From the above, it can be seen that the thickness of the light emitting layer alone after the formation of the mixed region is 80 nm.

  Similarly, when the concentration distribution of iridium in the depth direction was measured, it was not observed up to 45 nm, and showed a constant concentration after a rapid concentration increase toward 50 nm.

  When the above measurements were performed for 10 arbitrary points, it was confirmed that the concentration distribution in the depth direction of both aluminum and iridium had the same tendency, and a uniform concentration gradient was observed between the light emitting layer and the electron transport layer. It was confirmed that a mixed region was formed.

(Measurement equipment and measurement conditions for secondary ion mass spectrometry)
In the analysis of the concentration gradient in the mixed region of the organic EL element using a commercially available secondary ion mass spectrometer (SIMS), Al and Ir were respectively set as target elements.

<< Preparation of Organic EL Element 1-2 >>: Comparative Example Element Configuration Cathode: Al
Cathode buffer layer (deposition): LiF
Mixed layer: (No continuous concentration gradient, showing light emission function and electron transport function.)
Electron transport function: BAlq ₃
Light emitting function: PVK + PD-1 (Ir (ppy) ₃ )
Hole transport layer (water dispersion coating): PEDOT / PSS
Anode: ITO
In the formation of the light emitting layer and the electron transport layer of the glass substrate element, after forming the lower layer (light emitting layer), a part of the solvent (solvent within the solubility parameter range) that can dissolve the lower layer (light emitting layer) without heating and drying. When the upper layer (electron transport layer) was applied and formed using the mixed solvent contained, the coating liquid for forming the upper layer (electron transport layer) was coated on the lower layer (light emitting layer), resulting in the lower layer (light emitting). Layer) and an upper layer (electron transport layer) were mixed to form a mixed layer.

  After patterning on a substrate (NA-45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 100 nm of ITO (indium tin oxide) on a 100 mm × 100 mm × 1.1 mm glass substrate as an anode, this ITO transparent electrode was provided. The transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  On this transparent support substrate, a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water at 3000 rpm for 30 seconds. After forming the film by spin coating, the film was dried at 200 ° C. for 1 hour to provide a hole transport layer having a thickness of 30 nm.

  The substrate provided with the hole transport layer was transferred to a glove box substituted with nitrogen gas, and the subsequent operations were performed in the glove box.

A solution prepared by dissolving 30 mg of polyvinyl N-carbazole (PVK) and 1.5 mg of PD-1 (Ir (ppy) ₃ ) in 3 ml of dichlorobenzene on a hole transport layer was spinned under conditions of 1000 rpm and 30 seconds. A film is formed by a coating method (the light emitting layer is coated), and then 30 mg of bis (2-methyl-8-quinolate) -p-phenylphenolate aluminum complex (BAlq) is dissolved in 2 ml of tetrahydrofuran. A BAlq solution prepared by slowly adding 4 ml of hot toluene and then slowly returning to room temperature was formed by spin coating under the condition of 1000 rpm for 30 seconds (the electron transport layer was coated), 100 ° C. And dried in a vacuum for 1 hour, and the mixed layer (the components of the light emitting layer and the electron transport layer are mixed with each other). Transport functions are each a multi-functional layer) was formed. The total film thickness from the hole transport layer at this time was 70 nm.

  The mixed layer is formed by depositing the PD-1 solution on the hole transport layer using a spin coating method, and then coating the BAlq solution by a spin coating method (or film formation) and / or It is formed in a drying step after the step.

The substrate is attached to a vacuum deposition apparatus, and then the vacuum chamber is decompressed to 4 × 10 ⁻⁴ Pa, lithium fluoride 0.5 nm is deposited as a cathode buffer layer and aluminum 110 nm is deposited as a cathode to form a cathode, and organic EL Element 1-2 was produced.

<< Concentration analysis of mixed region (Al, Ir as target elements) >>
Similarly to the obtained organic EL element 1-2, the concentration distribution in the depth direction of aluminum and iridium was measured for the element 2 formed up to the mixed layer using secondary ion mass spectrometry.

  Unlike the case of the organic EL element 1-1 of the present invention, aluminum was detected from the upper surface of the mixed layer to near 90 nm. In iridium, it was also observed on the top surface of the film.

  Considering that the total film thickness is 70 nm, in the device 1-2, the configuration of the light emitting layer is greatly disturbed by the coating film of the electron transport layer, and the light emitting layer and the electron transport layer are mixed with each other, that is, In the mixed layer of Ir (iridium) element, which is one of the constituent components of the light emitting layer, or Al (aluminum) element, which is one of the constituent components of the electron transport layer, the continuous concentration as in the mixed region according to the present invention. It was found that a region having a gradient was not formed.

  Therefore, the present invention is a laminated element that is an effect of the present invention, and the concentration distribution of constituent components such as Al, which is a target element of an electron transport material, and Ir, which is a target element of a light emitting material, has a continuous concentration gradient. The mixed region according to the invention is not formed.

<< Preparation of Organic EL Element 1-3 >>: Structure of Element of Present Invention Cathode: Al
Cathode buffer layer (deposition): Ca
Light emitting layer (solution application): OC-45 + PD-1 (Ir (ppy) ₃ )
Mixing area (with concentration gradient)
Electron transport function: OC-45
Light emitting function: PD-1 (Ir (ppy) ₃ ) + PVK
Second hole transport layer (solution coating): PVK
First hole transport layer (water dispersion coating): PEDOT / PSS
Anode: ITO
Glass substrate After patterning on a substrate (NH-Techno Glass Co., Ltd. NA-45) formed by depositing 100 nm of ITO (indium tin oxide) on a 100 mm × 100 mm × 1.1 mm glass substrate as an anode, this ITO transparent electrode The provided transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  On this transparent support substrate, a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water at 3000 rpm for 30 seconds. After the film formation by spin coating, the film was dried at 200 ° C. for 1 hour to provide a first hole transport layer having a thickness of 30 nm. The substrate provided with the first hole transport layer was transferred to a glove box substituted with nitrogen gas, and the subsequent operations were performed in the glove box.

  A solution prepared by dissolving 20 mg of polyvinyl N-carbazole (PVK) in 3 ml of dichlorobenzene on the first hole transporting layer was formed into a film by spin coating at 3000 rpm for 30 seconds. It vacuum-dried for 1 hour, and produced the 30-nm-thick 2nd positive hole transport layer.

  30 mg of OC-45 and 1.5 mg of PD-1 were dissolved in 2 ml of tetrahydrofuran, 4 ml of hot toluene was slowly added to this solution, and then slowly returned to room temperature, and further cooled to -5 ° C. On the other hand, cold nitrogen gas (liquid nitrogen vaporized gas) is blown onto the second hole transport layer, which has been sufficiently cooled in advance, to form the solution by spin coating under the condition of 1000 rpm for 30 seconds. And vacuum drying at 100 ° C. for 1 hour to obtain a light emitting layer having a thickness of 80 nm.

This substrate is attached to a vacuum deposition apparatus, and then the vacuum chamber is decompressed to 4 × 10 ⁻⁴ Pa, and 10 nm of calcium is deposited as a cathode buffer layer and 110 nm of aluminum is deposited as a cathode to form a cathode. Was made.

<< Concentration analysis of mixed region (Al, Ir as target elements) >>
About obtained organic EL element 1-3, it carried out similarly to the said organic EL element 1-1, 1-2, and measured the concentration distribution of the depth direction of iridium using the secondary ion mass spectrometry.

  The analysis confirmed that a mixed region having a continuous concentration gradient of Ir (iridium) element concentration distribution was formed between the second hole transport layer and the light emitting layer.

<< Evaluation of Organic EL Elements 1-1 to 1-3 >>
When evaluating the obtained organic EL elements 1-1 to 1-3, the non-light-emitting surface of each organic EL element after production is covered with a glass case, and a glass substrate having a thickness of 300 μm is used as a sealing substrate. An epoxy-based photo-curing adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.) is applied as a sealing material in the periphery, and this is placed on the cathode to be in close contact with the transparent support substrate and irradiated with UV light from the glass substrate side. Then, it was cured and sealed, and an illumination device as shown in FIGS. 5 and 6 was formed and evaluated.

  FIG. 5 shows a schematic diagram of a lighting device, in which the organic EL element 101 is covered with a glass cover 102 (note that the sealing operation with the glass cover is performed without bringing the organic EL element 101 into contact with the atmosphere. (It was performed in a glove box under an atmosphere (under an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more)). FIG. 6 shows a cross-sectional view of the lighting device. In FIG. 6, 105 denotes a cathode, 106 denotes an organic EL layer, and 107 denotes a glass substrate with a transparent electrode. The glass cover 102 is filled with nitrogen gas 108 and a water catching agent 109 is provided.

《External extraction quantum efficiency》
About each of the produced organic EL elements 1-1 to 1-3, the external extraction quantum efficiency (%) was measured when a ^2.5 mA / cm ² constant current was applied at 23 ° C. in a dry nitrogen gas atmosphere. For the measurement, a spectral radiance meter CS-1000 (manufactured by Minolta) was used.

<Luminescent life>
For each of the produced organic EL devices 1-1 to 1-3, the luminance immediately after the start of light emission (initial luminance) when driven at a constant current of ^2.5 mA / cm ^{2 in} a dry nitrogen gas atmosphere at 23 ° C. ) Was measured as a half life time (τ0.5) and used as an index of life. In addition, the spectral radiance meter CS-1000 (made by Minolta) was similarly used for the measurement.

<Drive voltage>
For each of the produced organic EL elements 1-1 to 1-3, the voltage at which light emission was started was measured at a temperature of 23 ° C. and in a dry nitrogen gas atmosphere. Note that the voltage at the start of light emission was measured when the luminance was 50 cd / m ² or more. A spectral radiance meter CS-1000 (manufactured by Minolta) was used for the measurement of luminance.

  The measurement results of the external extraction quantum efficiency, the light emission lifetime, and the driving voltage of the organic EL elements 1-1 and 1-2 were subjected to relative evaluation when the organic EL element 1-3 was used as a standard.

  For relative evaluation, the following rank evaluation was performed.

◎: When the standard value is increased by 70% or more ○: When the standard value is increased by 30% or more △: When the standard value is increased by 30% ×: When the standard value is decreased by 30% The results obtained are as follows: Table 1 shows.

From Table 1, as compared with the organic EL element 1 2 comparison, both the organic EL element 1-1,1- 3 of the present invention, the quantum efficiency extraction outer portion (which is a high luminous efficiency) high, the emission lifetime It is clear that the driving voltage of the element is reduced.

Example 2
A full color display device provided with the organic EL element of the present invention was produced as follows.

  First, a part of the constituent layers of the organic EL element of the present invention was manufactured using an ink jet. Here, a manufacturing process of an organic EL element using an ink jet will be described with reference to FIGS.

<< Preparation of Organic EL Element 2-1 >>
FIG. 7 is a schematic view showing an example of a manufacturing process of a full-color display device by an inkjet method. First, ITO (indium tin oxide) (202) is formed on a glass substrate (201) of 100 mm × 100 mm × 1.1 mm as an anode. After patterning on a 100 nm thick substrate (NA-45 manufactured by NH Techno Glass), a non-photosensitive polyimide partition (203) (width 20 μm, thickness 2 between the ITO transparent electrodes on this glass substrate) 0.0 μm) was formed by photolithography.

  A first hole injection layer composition having the following composition is injected and injected between polyimide partition walls on the ITO electrode using an inkjet head (manufactured by Epson Corporation; MJ800C), and a film thickness of 30 nm is obtained by drying at 200 ° C. for 10 minutes. A first hole transport layer 204a was produced.

  Similarly, a second hole injection layer composition having the following composition is discharged and injected onto the first hole transport layer using an inkjet head, and dried at 150 ° C. for 20 minutes to give a second film having a thickness of 30 nm. A hole transport layer 204b was produced.

  In advance, the substrate was sufficiently cooled by blowing cold nitrogen gas, and then the following blue light-emitting composition, green light-emitting composition, and red light-emitting composition were similarly ejected and injected using an inkjet head. Furthermore, each light emitting layer (205B, 205G, 205R) was formed with a film thickness of 30 nm by drying at 100 ° C. for 10 minutes.

This substrate is attached to a vacuum deposition apparatus, and then the vacuum chamber is decompressed to 4 × 10 ⁻⁴ Pa, and 10 nm of calcium and 110 nm of aluminum are deposited as a cathode buffer layer and a cathode (206), respectively, and vacuum deposition is performed. Organic EL element 2-1 was produced.

<Production of full-color display device>
An active matrix type full-color display device having the form shown in FIG. 1 is manufactured using the manufactured organic EL element 2-1, and FIG. 2 shows only a schematic diagram of the display portion A of the manufactured display device. It was. That is, a wiring portion including a plurality of scanning lines 5 and data lines 6 on the same substrate, and a plurality of juxtaposed pixels 3 (light emission color is a red region pixel, a green region pixel, a blue region pixel, etc.) The scanning lines 5 and the plurality of data lines 6 in the wiring portion are each made of a conductive material, and the scanning lines 5 and the data lines 6 are orthogonal to each other in a lattice shape and are connected to the pixels 3 at orthogonal positions. (The details are not shown.)

  The plurality of pixels 3 are driven by an active matrix system provided with an organic EL element corresponding to each emission color, a switching transistor as an active element, and a driving transistor, and a scanning signal is applied from a scanning line 5. Then, an image data signal is received from the data line 6 and light is emitted according to the received image data. In this way, a full color display device was produced by appropriately juxtaposing the red, green, and blue pixels.

  It was confirmed that by driving the full-color display device, a full-color moving image display having a high light emission efficiency and a long light emission life can be obtained.

(Preparation of first hole transport layer composition)
A solution obtained by diluting 20 g of poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Baytron, Baytron P Al 4083) with 65 g of pure water, 10 g of ethoxyethanol, and 5 g of glycerin was used.

(Preparation of second hole transport layer composition)
300 mg of PVK dissolved in 25 ml of cyclohexylbenzene and 25 ml of isopropylbiphenyl was used.

(Preparation of green light emitting layer composition)
A solution prepared by dissolving 300 mg of OC-45 and 15 mg of PD-1 in 25 ml of cyclohexylbenzene and 25 ml of tetralin was used.

(Preparation of blue light emitting layer composition)
300 mg of OC-45 and 15 mg of PD-9 dissolved in 25 ml of cyclohexylbenzene and 25 ml of tetralin were used.

(Preparation of red light emitting layer composition)
300 mg of OC-45 and 15 mg of PD-6 dissolved in 25 ml of cyclohexylbenzene and 25 ml of tetralin were used.

Example 3
《Preparation of white light emitting lighting device》
In the production of the organic EL element 1-3 produced in Example 1, the white light emitting organic EL element 3-1W was produced in the same manner except that PD-1 was changed to PD-1, PD-6, PD-9. did.

  In the same manner as in Examples 1 and 2, the obtained organic EL element 3-1W was covered with a glass case to form a lighting device. The illuminating device could be used as a thin illuminating device that emits white light with high luminous efficiency and long emission life.

It is the schematic diagram which showed an example of the display apparatus comprised from an organic EL element. It is a schematic diagram of a display part. It is a schematic diagram of a pixel. It is a schematic diagram of a passive matrix type full-color display device. It is the schematic of an illuminating device. It is sectional drawing of an illuminating device. It is a schematic diagram which shows an example of the manufacturing process of the full-color display apparatus by the inkjet method. It is a schematic diagram which shows an example of the organic EL element of this invention in which the mixed area | region is formed between the light emitting layer and the electron carrying layer. It is a schematic diagram which shows an example in which the concentration distribution of the luminescent material which comprises a light emitting layer has shown the continuous concentration gradient in the mixing area | region formed between the light emitting layer and the electron carrying layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Display 3 Pixel 5 Scan line 6 Data line 7 Power supply line 10 Organic EL element 11 Switching transistor 12 Drive transistor 13 Capacitor A Display part B Control part 107 Glass substrate with a transparent electrode 106 Organic EL layer 105 Cathode 102 Glass cover 108 Nitrogen gas 109 Water catcher

Claims (5)

In the organic electroluminescence device having at least three organic layers including a light emitting layer, a hole transport layer and an electron transport layer as a constituent layer between the cathode and the anode,
A coating solution comprising a mixed region between layer A and layer B, which is at least two layers of the organic layer, wherein the layer A contains a light emitting host material and a phosphorescent light emitting material. A light-emitting layer formed by coating, and layer B is a hole transport layer or an electron transport layer formed by coating a coating solution composed of a non-aqueous solvent that does not contain the phosphorescent light-emitting material . ,且 one, in the mixing region, the organic electroluminescence element concentration distribution of the phosphorescent light emitting material, characterized in that it presents a continuous density gradient. The organic electroluminescence device according to claim 1, which emits white light. A display device comprising the organic electroluminescence element according to claim 1. An illuminating device comprising the organic electroluminescent element according to claim 1. A display device comprising the lighting device according to claim 4 and a liquid crystal element as a display means.

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