TWI507505B - Organic electroluminescent device using 2-methylanthracene compound - Google Patents

Description

Organic electroluminescent device using 2-methylindole compound

The present invention relates to an organic light-emitting diode and a manufacturing method thereof. More specifically, it relates to a green light-emitting organic light-emitting diode which has excellent luminous efficiency, brightness and chromaticity.

Since Dr. Deng Qingyun from Keda Company of the United States reported on low-voltage organic electroluminescent devices (CWTang, Applied Physics Letters, 51, 913, 1987), it has caused a research boom in the application of organic compounds to organic electroluminescent devices. The organic electroluminescent device is sandwiched between two electrodes (anode and cathode) via an organic medium to form a sandwich structure in which the anode is a metal having a high work function or a conductive compound such as ITO, IZO, SnO2 a transparent metal oxide such as ZnO or the like, or a TFT substrate such as poly-Si or a-Si; and the cathode is a metal or a conductive compound having a low work function, for example, Au, Al, In, Mg, Ca Or a similar metal, alloy, etc.; and at least one of the two electrodes is transparent or translucent so that the emitted light can penetrate efficiently. The organic medium may be composed of several layers depending on the case, wherein the thickness of each layer is not strictly limited, and is usually between 5 nm and 5 μm, and representatively, three layers of organic molecules are sandwiched between the two electrodes, and the three layers include one electron. Transport layer, a light-emitting layer and a hole transport layer. Usually, in order to reduce the driving voltage, a hole or an electron injecting layer is additionally added, or a light hole or an electron blocking layer is added to improve the luminous efficiency, and an organic electroluminescent device composed of four to six organic molecular layers is formed; wherein the electron injecting layer is formed. It is usually possible to use an alkali metal halide or a nitrogen-containing, oxygen-containing alkali metal chelate compound, for example: LiF, 8-quinolinolato lithium (Liq), etc.; and the hole injection layer can usually be derived from metal Phthalocyanine derivatives, star-shaped polyamine derivatives, polyaniline derivatives (Y.Yang et al, Syn.Met. , 1997, 87, 171), perfluorinated, SiO2 (ZBDeng et al, Appl. Phys. Lett., 1997, 74, 2227) or hole transport material doped oxides, etc., for example: CuPc (SAVanslyke et al, Appl. Phys. Lett., 1996, 69, 2160), MTDATA (Y. Shirota et al, Appl. Phys. Lett., 1994, 65, 807), TPD + SbCl6- (A. Yamamori et al, Appl. Phys. Lett., 1998, 72, 2147), PEDOT-PSS (A. Elschner et al, Syn. Met., 2000, 111, 139), etc.; the electron transport layer may be a metal chelate containing nitrogen and oxygen (T. Sano et al, J. Mater.Chem., 2000, 10, 157), an oxadiazole derivative, a perfluorinated polyaromatic ring derivative, an aromatic or heterocyclic substituted silole derivative, an oligothiophene derivative or a benzimidazole derivative, for example: tris (8- Quinolinolato)aluminum (Alq3), PBD (N. Johansson et al, Adv. Mater., 1998, 10, 1136), PyPySiPyPy (M. Uchida et al, Chem. Mater., 2001, 13, 2680), BMB-3T (T.Noda et al, Ady.Mater., 1999, 1 1,283), PF-6P (Y. Sakamoto et al, J. Amer. Chem. Soc., 2000, 122, 1832), TPBI (YTTao et al, Appl. Phys. Lett., 2000, 77, 933), etc.; The hole transport layer is usually composed of a charge transport material for a hole in an organic photoconductive material, which may be a triazole derivative, an oxadiazole derivative, an imidazole derivative, a phenylenediamine derivative, or a stellate polyamine derivative. , consisting of a spiro-linked molecular derivative or an arylamine derivative, for example, NPB or a derivative thereof (Y. Sato et al, Syn. Met., 2000, 111, 25), PTDATA (Y. Shirota et al, Syn. Met., 2000, 111, 387), spiro-mTTB (U. Bach et al, Adv. Mater., 2000, 12, 1060) and the like. Since OLEDs have low driving voltage characteristics and have been verified to be applicable to full color flat panel displays, research on organic electroluminescent devices and materials has attracted worldwide attention and investment.

In order to improve the illuminating color, illuminating efficiency, illuminating stability, component life, and component manufacturing method of the organic electroluminescent device, the improvement results can be referred to the issued U.S. Patent Nos. 4,356,429, 4,539,507, 4,720,432. Nos. 4,885,211, 5,151,629, 5,150,006, 5,141,671, 5,073,446, 5,061,569, 5,059,862, 5,059,861, 5,047,687, 4,950,950, 4,769,292, 5,104,740, 5,227,252 No. 5,256,945, 5,069,975, 5,122,711, 5,366,811, 5,126,214, 5,142,343, 5,389,444, 5,458,977, and the like.

In terms of green fluorescent dopants, Deng Qingyun et al. for 10-(1,3-benzothiazol-2-tl)-1,1,7,7-tetramethyl-2.3.6.7-tetrahydro-1H, 5H, 11H- Pyrano-[2,3-f]pyrido[3,2,1-ij]quinolinllone (C545T for short) was found to be a trace amount (0.5%~1.0% by volume) of the compound doped in the main illuminant. The green light components can achieve good performance in line with commercial requirements. Now Kodak, Pioneer, Sanyo and other companies have applied this compound to organic light-emitting diodes. Although the green light-emitting element made by the C545T doping in the main illuminant has good characteristics, such a light-emitting element still has some disadvantages; in particular, its optimum luminous efficiency occurs at a C545T doping concentration of about 0.5% to 1.0%. Between this, once this optimum concentration has passed After that, the luminous efficiency of the component is greatly reduced as the doping concentration increases. This characteristic makes it necessary to precisely control the C545T doping concentration when the component is fabricated. Such narrow concentration doping optimization operation conditions are quite difficult and inconvenient for component fabrication. Because of the molecular structure of C545T, the double bond between No. 3 and No. 4 carbon in the oxygen-containing heterocyclic ring is likely to undergo a [2+2] cyclization reaction via photochemistry, thereby forming a dimer, destroying the original chromophore. The resonance structure causes the quenching of the fluorescent light to cause the above phenomenon to occur.

To improve the disadvantages of previously published green light dopant materials, the present invention provides a green organic compound, as shown in Formula I, wherein Y ₁ , Y ₂ , Y ₃ and Y ₄ each represent 6 to 20 carbon atoms. A substituted or unsubstituted aromatic group is formed.

Another object of the present invention is to provide a green organic electroluminescent device device having high luminous efficiency, saturated color purity, and long device operational stability. The organic electroluminescent device is composed of at least one pair of electrodes, and comprises a single layer or a multi-layer structure composed of an anode, a cathode and an organic compound between the electrodes, wherein at least one organic layer contains the compound of the above formula I .

In the light-emitting layer of the organic electroluminescent device, when the green of the present invention a photoorganic compound, as shown in Formula I, is doped in a host illuminant material in the form of a guest illuminant material, which can be recombined directly into the guest illuminant via energy transfer between the host and guest illuminant materials or electron/holes. The mechanism reduces the generation of the non-light-emitting mechanism and increases the luminous efficiency and operational stability of the element, and obtains a green light element with high saturation chromaticity. The doping concentration of the guest illuminant material may be between 0.01% and 50% by weight for the main illuminant, and a preferred doping concentration is 0.5% to 20% by weight.

The green organic compound of the present invention is as shown in Formula I, and is mainly applicable to an organic material required for an organic electroluminescent device, and a high luminous efficiency, saturated color purity, and long component can be obtained as a luminescent material in the current period. Green light component for operational stability.

The green-light organic compound of the present invention, which is substituted and unsubstituted aromatic examples such as phenyl, 2-tolyl, 3-tolyl, 4-tolyl, 3,4-dimethylphenyl, naphthyl, and anthracene Base, but not limited to this category. The compounds listed below are representative of the green-light organic compounds of the present invention, and any concomitant related derivatives will be encompassed within the spirit of the present invention.

The invention can be applied to several different excitation motor light-emitting devices, wherein the necessary composition is a cathode, an anode and an organic layer therebetween, and the organic layer may include a hole injection layer, a hole transport layer, a light-emitting layer, and The electron transport layer; as shown in the first figure, is the most typical structure, including the substrate 11, the anode 12, the unnecessary hole injection layer 13, the hole transport layer 14, the light-emitting layer 15, the electron transport layer 16, and the electron injection layer. 17, the metal cathode 18 and the power source 19, when a voltage is applied between the two electrodes, the holes generated by the anode and the electrons generated by the cathode are injected into the organic layer to be combined into excitons, and when excitons Light is scattered when it is lowered to the ground state.

The materials used in these layers are described carefully below. It must first be noted that the substrate can be selectively placed next to the cathode, or the substrate can be an anode or a cathode, and further, the total thickness of all organic layers is preferably less than 500 nm.

It is to be noted that those skilled in the art can make organic electroluminescent devices or devices using the compounds of the present invention in accordance with conventional techniques or prior art or prior art methods described in the present specification. Hereinafter, suitable materials for the structure of each element other than the hole injection layer in the organic electroluminescent device or device of the present invention will be described.

Substrate

The substrate may be translucent or opaque depending on the direction in which the light is emitted. If the EL emission is to be observed from the substrate, the substrate must have light penetrability. In this case, glass or organic materials are generally used. And if the EL emission is to be observed through the upper electrode, the light passage of the lower support will become irrelevant, so it can be light penetration, light absorption or light reflection. At this time, the material of the substrate can be used but Not limited to glass, plastic, Semiconductor materials, ceramics, and circuit board materials, of course, such component structures must provide a light transmissive upper electrode.

anode

The conductive anode layer is typically fabricated on a substrate, and when EL radiation is observed through the anode, the anode must be transparent or substantially transparent to certain radiation; a generally common transparent anode for use in the present invention - Indium tin oxide (ITO), but other metal oxides can still be used, including but not limited to aluminum or indium doped zinc oxide (IZO), magnesium-indium oxide Magnesium-indium oxide and nickel-tungsten oxide, in addition to these oxides, metal nitrides such as gallium nitride, and metal selenides such as zinc selenide (zinc) Selenide), and metal sulfides such as zinc sulfide can be used for this layer. In applications where EL radiation is observed through the upper electrode, the light transmission of the layer is no longer important, and any electrically conductive material, transparent, opaque, or reflective material can be used. Materials used include, but are not limited to, gold, ruthenium, molybdenum, palladium, and platinum. Generally, the anode material, whether transparent or not, has a work function of usually greater than or equal to 4.1 eV, and the required anode material is usually deposited in an appropriate manner, such as evaporation, sputtering, chemical vapor deposition, or electrochemical methods. The anode can be patterned by well-known photolithography etching.

Hole-transporting layer (HTL)

The hole transport layer of the organic EL element includes at least one hole conduction Compounds, such as aromatic tertiary amines, it is inferred today that such compounds contain at least one trivalent nitrogen atom bonded only to a carbon atom, and at least one of the carbon atoms is one of the aromatic rings; One of these aromatic tertiary amines may be an arylamine such as a monoarylamine, a bisarylamine, a triarylamine or a high molecular aromatic amine group; a monomeric triarylamine A model is described by Klupfel et al. in US Pat. No. 3,180,730; and other suitable triarylamines are disclosed by Brantley et al. in US Pat. Nos. 3,567,450 and 3,658,520, relating to one or more vinyl radicals and/or Or a triarylalkylamine substituted with at least one group containing an active hydrogen.

One of the most useful aromatic tertiary amines is described in US Pat. Nos. 4,720,432 and 5,061,569: aromatic tertiary amines containing at least two aromatic tertiary amine groups, the following are useful An example of an aromatic tertiary amine: 1,1-bis(4-di-p-tolylamidophenyl)cyclohexane, 1,1-bis(4-di-p-tolylaminophenyl) 4-phenyl-cyclohexane, 4,4'-bis(diphenylamino)tetraphenyl, bis(4-dimethylamino-2-methylphenyl)-phenylmethane, N, N,N-tris(p-tolyl)amine, 4-(di-p-tolylamino)-4'-[4(di-p-tolylamino)-styryl]indole, N, N,N',N'-tetra-p-tolyl-4,4'-diaminobiphenyl, N,N,N',N'-tetraphenyl-4,4'-diaminobiphenyl ,N,N,N',N'-tetra-1-naphthyl-4,4'-diaminobiphenyl, N,N,N',N'-tetra-2-naphthyl-4,4' -diaminobiphenyl, N-phenylcarbazole, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl, 4,4'-bis[N-(1-naphthyl)-N -(2-naphthyl)amino]biphenyl, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]p-terphenyl, 4,4'-double [N -(2-naphthyl)-N-phenylamino]biphenyl, 1,5-bis[N-(1-naphthyl)-N-phenylamino]naphthalene, 4,4'-double [N -(9-fluorenyl)-N-phenylamino]biphenyl, 4,4'-bis[N-(1-indenyl)-N-phenylamino]p-terphenyl, 4,4 '-Bis[N-(2-phenanthryl)-N-phenylamino]biphenyl, 4,4'-bis[N-(8-fluorodecenyl)-N-phenylamino]biphenyl ,4,4'-bis[N-(2-pyrenyl)-N-phenylamino]biphenyl, 4,4'-bis[N-(2-naphthacenyl)-N-phenylamino]biphenyl , 4,4'-bis[N-(2-perylenyl)-N-phenylamino]biphenyl, 4,4'-bis[N-(2-arginyl)-N-phenylamino] Benzene, 2,6-bis(di-p-tolylamino)naphthalene, 2,6-bis(di-(1-naphthyl)amino)naphthalene, 2,6-bis[N-(1-naphthalene) -N-(2-naphthyl)amino]naphthalene, N,N,N',N'-tetrakis(2-naphthyl)-4,4"-diamine -p-terphenylene, 4,4'-bis{N-phenyl-N-[4-(1-naphthyl)-phenyl]amino}biphenyl, 4,4'-bis[N-benzene Benzyl-N-(2-pyrenyl)amino]biphenyl, 2,6-bis[N,N-bis(2-naphthyl)amino]indole, or 1,5-bis[N-(1-naphthalene) Base) -N-phenylamino]naphthalene.

Another useful hole transport material is the polycyclic aromatic compound described in EP 1 009 041. In addition, polymeric hole transport materials can also be used, such as poly(N-vinylcarbazole) (PVK). , polythiophene, polypyrrole, poly Aniline and copolymerized polymers such as poly(3,4-extended ethyldioxythiophene)/poly(4-styrene-sulfonate) are also known as PEDOT/PSS.

Electron transport layer (ETL)

In the invention, the film material of the electron transport layer of a suitable organic EL element is a metal chelate 8-oxoquinoline (oxinoid) compound comprising an 8-oxoquine chelating group (generally related to 8 - quinolol or 8-hydroxyquinoline); such compounds can aid in the injection and transport of electrons and produce a film pattern of high efficiency and ease of fabrication; the more important 8-hydroxyquinoline compound is in accordance with the above molecular structure a compound of formula (E).

Other various butadiene derivatives disclosed in US Pat. No. 4,356,429 and the various heterocyclic optical brighteners described in US Pat. No. 4,539,507, which are incorporated herein by reference. The benzazepines of G) are also useful as electron transport materials.

In some instances, the luminescent layer and the electron transport layer can be selectively combined into a single layer, which can simultaneously accommodate both luminescence and electron transport.

Cathode

If the electroluminescent light is designed to be permeable from the anode, almost any electrically conductive material in the invention can form a cathode, wherein the more desirable material property is good film formation, which ensures that the cathode and the underlying organic layer are good. Contact, which in turn enhances the injection of electrons at low voltages, and has good stability; useful cathode materials are typically low work function metals (<4.0 eV) or metal alloys; described in US Pat. No. 4,885,221 Magnesium-silver alloy (Mg: Ag) is one of the suitable cathode materials, wherein the ratio of silver is 1 to 20%; A suitable cathode material is a two-layer structure comprising a thick conductive metal layer covering a low work function metal thin layer or a metal salt. The cathode described in US Pat. No. 5,677,572 is a thin layer of LiF and an Al. Other useful cathode materials include, but are not limited to, the materials disclosed in US Pat. Nos. 5,059,861, 5,059,862 and 6,140,763.

When the component is designed to emit light through the cathode, the cathode must be transparent or nearly transparent. In this case, the metal must be thin or a transparent conductive oxide must be used, or a combination of these materials; US A detailed description of an optically transparent cathode is provided in Pat. No. 5,776,623; the method of depositing the cathode material may be evaporation, sputtering, or chemical vapor deposition, and if necessary, the cathode may be Patterning, in many well known ways, including, but not limited to, through-mask deposition, integral mask technology as described in US Pat. No. 5,276,380 and EP 0 732 868. (integral shadow masking), laser ablation and selective chemical vapor deposition.

In addition, in order to improve the illuminating color, illuminating efficiency, illuminating stability, component life, and component manufacturing method of the organic electroluminescent device, reference is made to the issued U.S. Patent Nos. 4,356,429, 4,539,507, 4,720,432, 4,885,211, 5,151,629, 5,150,006, 5,141,671, 5,073,446, 5,061,569, 5,059,862, 5,059,861, 5,047,687, 4,950,950, 4,769,292, 5,104,740, 5,227,252 , 5, 256, 945, 5, 069, 975, 5, 122, 711, 5, 366, 811, 5, 126, 214, 5, 142, 343, 5, 389, 444, 5,458,977 and so on.

In a specific embodiment of the invention, the organic electroluminescent device is a display. In general, the display can be used in televisions, mobile phones, computer monitors, monitors, devices and/or electrical appliances or other devices that can use displays and/or devices used in various individuals, homes, offices, and/or vehicles. Electrical appliances.

The following is a method for carrying out the invention: indium tin oxide (ITO) / hole injection layer (HIL) / hole transport layer (HTL) / green light emitting layer (EML) / electron transport layer (ETL) / electron injection layer (EIL) ) / aluminum (Al) (unit: nano nm). Please refer to the sectional view of the device in the first figure.

The vacuum film evaporator (coater) is a TRC 18-inch rotary evaporator, which can hold 9 baffles, 8 electric enthalpy, 5 oscillating sensors, IC-5 film thickness controller and diffusion gang Pu.

A spectrophotometer (colorimeter) was measured using a PhotoResearch PR-650 instrument.

A programmable power supply supplies current using a KEITHLEY 2400 instrument.

The production procedure was as follows: First, deionized water, ultrasonic washing, transparent electrode, indium tin oxide (ITO), and then ultraviolet (oxygen) irradiation for 10 minutes were used. The cleaned glass substrate is moved into a vacuum vapor deposition apparatus. The operation begins when the vacuum of the vacuum vapor deposition apparatus reaches 10 ^-6 Torr (TORR).

On the surface having the transparent electrode, a film S707 was formed to have a thickness of 100 nm, so that the formed film cover was transparent. The film formed by S707 serves as a first hole injection layer (hole transport layer). Then, 20 nm of N,N'-bis(a-naphthyl)-N,N'-biphenyl-4,4'- hydrazine (NPB) was formed on S707. The formed film is a second hole injection layer (hole transport layer).

The compound of formula I and MADN were mixed by vacuum vapor deposition to form a luminescent layer having a thickness of 30 nm.

Further, a film having a thickness of 10 nm was formed as an electron injecting layer by 8-hydroxyquinoline aluminum (Alq). Thereafter, lithium fluoride (LiF) was deposited on Alq as an electron injection layer (cathode). Finally, the metal aluminum is vapor deposited to form a metal cathode to form a green organic light emitting diode.

Embodiment 1:

(a) ITO (Indium Tin Oxide) glass substrate 40 mm x 40 mm thick 1.1 mm, ultrasonically cleaned in methanol for 12 minutes, and then irradiated with ultraviolet rays (to produce ozone) for 10 minutes. The cleaned glass substrate is moved into a vacuum vapor deposition apparatus.

(b) On the surface having the transparent electrode, a film S707 was formed to have a thickness of 75 nm, so that the formed film cover was transparent. The formed thin film S707 serves as a first hole injection layer (hole transport layer).

(c) A 15 nm NPB was then formed on S707. The formed film is a second hole injection layer (hole transport layer).

(d) Compound E502 and MADN were mixed by vacuum vapor deposition to form MADN having a thickness of 30 nm and E502 containing 7% as a light-emitting layer.

(e) A film having a thickness of 25 nm was formed as an electron injecting layer by Alq.

(f) Lithium fluoride (LiF) was deposited on Alq as an electron injecting layer (cathode).

(g) Finally, metal aluminum is vapor-deposited to form a metal cathode to form an organic electroluminescent diode.

(h) The element fabricated above is subjected to a current and its luminance and luminance efficiency are measured by light color.

When the organic electroluminescence photodiode was driven at a current density of 20 mA/cm ² , the driving voltage was 5.69 V, and green light was emitted, and the luminance of CIE (0.289, 0.644) was 4026.26 cd/m ² , and the luminous efficiency was 20.13 cd/A.

Embodiment 2:

The organic electroluminescent diode was fabricated, and according to the procedure of Example 1, MADN having a thickness of 30 nm and E505 containing 3% were used as the light-emitting layer.

When the organic electroluminescence diode was driven at a current density of 20 mA/cm ² , the driving voltage was 6.95 V, and green light was emitted, and the luminance of CIE (0.306, 0.634) was 2802.27 cd/m ² , and the luminous efficiency was 14.01 cd/A.

Embodiment 3:

The organic electroluminescent diode was fabricated, and according to the procedure of Example 1, MADN having a thickness of 30 nm and E506 containing 5% were used as the light-emitting layer.

When the organic electroluminescent diode was driven at a current density of 20 mA/cm ² , the driving voltage was 6.05 V, and green light was emitted, and the luminance of CIE (0.314, 0.633) was 4533.58 cd/m ² , and the luminous efficiency was 22.66 cd/A.

Embodiment 4:

The organic electroluminescent diode was fabricated. According to the procedure of the second embodiment, MADN having a thickness of 37.5 nm and E507 having a thickness of 12% were used as the light-emitting layer.

When the organic electroluminescence diode was driven at a current density of 20 mA/cm ² , the driving voltage was 8.02 V, and blue-green light, CIE (0.344, 0.613) luminance was 3337.96 cd/m ² , and the luminous efficiency was 16.69 cd/A.

Embodiment 5:

The organic electroluminescent diode was fabricated. According to the procedure of Example 1, MADN having a thickness of 30 nm and E512 containing 3% were used as the light-emitting layer.

When the organic electroluminescence diode was driven at a current density of 20 mA/cm ² , the driving voltage was 6.58 V, and green light was emitted. The luminance of CIE (0.353, 0.620) was 4567.78 cd/m ² and the luminous efficiency was 22.83 cd/A.

Comparative example:

The ITO (Indium Tin Oxide) glass substrate was 40 mm x 40 mm thick and 1.1 mm thick, ultrasonically cleaned in methanol for 12 minutes, and then irradiated with ultraviolet rays (to produce ozone) for 10 minutes. Move the cleaned glass substrate into the vacuum gas Phase deposition equipment. On the surface having the transparent electrode, a film S707 was formed to have a thickness of 100 nm, so that the formed film cover was transparent. The formed thin film S707 serves as a first hole injection layer (hole transport layer). A 20 nm NPB was then formed on S707. The formed film is a second hole injection layer (hole transport layer). Compound C545T and MADN were mixed by vacuum vapor deposition to form MADN having a thickness of 30 nm and C545T containing 1% as a light-emitting layer. A film having a thickness of 15 nm was formed as an electron injecting layer by Alq. Thereafter, lithium fluoride (LiF) was deposited on Alq as an electron injection layer (cathode). Finally, the metal aluminum is vapor deposited to form a metal cathode, and the organic electroluminescent diode is prepared.

When the organic electroluminescence diode was driven at a current density of 20 mA/cm ² , the driving voltage was 8.28 V, and blue-green light, CIE (0.254, 0.613) luminance of 2885.40 cd/m ² , and luminous efficiency of 14.42 cd/A were emitted.

From Table 1, Table 2 and Table 3, after the series of compounds and C545T are fabricated into components, compared with C545T, E502 can reduce the driving voltage by 2.59V and increase the luminous efficiency by about 40%; E506 can reduce the driving voltage by 2.23V. And increase the luminous efficiency by about 57%; E507 can reduce the driving voltage by 0.26V and increase the luminous efficiency by about 16%; E512 can reduce the driving voltage by 1.7V and increase the luminous efficiency by about 58%. In terms of operational stability, the C545T is driven at a constant current of 4000 cd/m ² with a component lifetime (t _1/2 ) of 1770 hours; the E506 operates under the same conditions, and the component lifetime (t _1/2 ) increases by 4.46 times to 7900. hour. It is apparent that the green organic compound of the present invention is doped into a suitable host luminescent material, and the organic electroluminescent device thereof can obtain a green light element having high luminous efficiency, saturated color purity and long operational stability. The present invention is intended to be illustrative of specific examples, and any conceivable related derivatives are intended to cover the spirit and scope of the invention.

10‧‧‧Organic electroluminescent device

11‧‧‧ glass substrate

12‧‧‧Anode

13‧‧‧ hole injection layer

14‧‧‧ hole transport layer

15‧‧‧Lighting layer

16‧‧‧Electronic transport layer

17‧‧‧Electronic injection layer

18‧‧‧Metal cathode

19‧‧‧Power supply

The first figure is a schematic structural view of a general organic electroluminescent device.

10‧‧‧Organic electroluminescent device

11‧‧‧ glass substrate

12‧‧‧Anode

13‧‧‧ hole injection layer

14‧‧‧ hole transport layer

15‧‧‧Lighting layer

16‧‧‧Electronic transport layer

17‧‧‧Electronic injection layer

18‧‧‧Metal cathode

19‧‧‧Power supply

Claims (8)

An organic electroluminescent device using a 2-methylindole compound, comprising at least a cathode, an anode and an organic layer therebetween, wherein the organic layer comprises a hole injection layer, a hole transport layer, a light emitting layer, and a An electron transport layer, an electron injection layer, wherein at least one of the light-emitting layers comprises a main illuminant material and a guest illuminant material, wherein the main illuminant material is a quinone compound and a derivative thereof, and the guest illuminant material is 0.01 to less than 50% by weight of the compound of formula I: Wherein Y ₁ , Y ₂ , Y ₃ and Y ₄ represent the same or different C ₆ -C ₂₀ aryl groups optionally substituted by a C ₁ -C ₆ hydrocarbon group. An organic electroluminescent device using a 2-methylindole compound according to claim 1, wherein the main emitter material is selected from the group consisting of MADN and its derivatives. An organic electroluminescent device using a 2-methylindole compound as described in claim 1 or 2, wherein the guest emitter material is from 0.5 to 20% by weight of the compound of formula I. An organic electroluminescent device using a 2-methylindole compound according to claim 1 or 2, wherein the organic electroluminescent device emits green light. An organic electroluminescent device using a 2-methylindole compound according to claim 1 or 2, wherein the total thickness of each organic layer is less than 500 nm. An organic electroluminescent device using a 2-methylindole compound according to claim 1 or 2, wherein the C ₁ -C ₆ hydrocarbon group-substituted and unsubstituted aromatic group is a phenyl group, a 2-tolyl group, 3-tolyl, 4-tolyl, 3,4-dimethylphenyl, naphthyl or anthracenyl. An organic electroluminescent device using a 2-methylindole compound as described in claim 1 or 2, the guest emitter material may be selected from the following compounds: ,or ,or ,or ,or ,or ,or ,or ,or ,or ,or ,or ,or An organic electroluminescent device using a 2-methylindole compound as described in claim 1 or 2, wherein the compound of formula I is selected from the group consisting of In the group formed, and wherein the main system of illumination is selected from