JP2009227604A - New 3,6-disubstituted carbazole derivative, host material comprising the same and organic el element containing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new 3,6-disubstituted carbazole derivative, a host material comprising the same and an organic EL element containing the same. <P>SOLUTION: This 3,6-disubstituted carbazole derivative obtained by e.g. the reaction shown in the figure is exemplified, and the host material comprising the same derivative and the organic EL element containing the same are also provided. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a novel 3,6-disubstituted carbazole derivative, a host material comprising the same, and an organic EL device (organic electroluminescence device) containing the same.

  Research and development for the practical application of organic EL is being promoted mainly by domestic and foreign electric and material manufacturers. Reducing power consumption and prolonging the life of the elements are indispensable issues for walking alongside displays that are already known to the public such as liquid crystal display elements and light emitting diodes.

Thus, in order to solve this problem, an organic EL element using a phosphorescent material has been recently studied (Non-Patent Document 1).
Unlike conventional fluorescent materials, phosphorescent materials can use triplet excited states, so that quantum efficiency is very high, and there is almost no energy deactivation and the internal emission quantum yield reaches almost 100% ( Non-patent documents 2, 3, 4).
However, since this phosphorescent material easily causes concentration quenching, it is necessary to use it together with a host material in the same manner as a fluorescent material (Non-patent Document 5).
In order to obtain high-efficiency light emission, it is necessary to optimize transport materials and host materials, but unlike phosphor materials, phosphorescent materials cannot achieve satisfactory effects unless triplet energy is completely confined. Especially for blue materials, the energy level is very high. Therefore, the α-NPD that has been used so far cannot confine sufficient energy. Until now, there was no wide-gap transport material or host material that could confine this blue phosphorescent energy, which was one factor that hindered the development of blue phosphorescent materials.

M.M. A. Baldo, D.M. F. O'Brien, Y.M. You, A .; Shoustikov, S .; Sibrey, M.M. E. Thompson and S.M. R. Forrest: Nature (London) 395 p. 151 (1998) C. Adachi, M .; A. Baldo and S.M. R. Forrest: Appl. Phys. Lett. , 77 p. 904 (2000) C. Adachi, M .; A. Baldo, S .; R. Forrest, S.M. Lamansky, M .; E. Thompson and R.C. C. Wong: Appl. Phys. Lett. , 78, 1622 (2001) C. Adachi, R.A. C. Wong, P.M. Djurovic, V.M. Adamovich, M .; A. Baldo, M .; E. Thompson, and S.M. R. Forrest: Appl. Phys. Lett. 79, 2082 (2001) C. Adachi, M .; A. Baldo and S.M. R. Forrest: J.M. Appl. Phys. , 87, 8049 (2000)

  An object of the present invention is to provide a novel 3,6-disubstituted carbazole derivative, a host material comprising the derivative, and an organic EL device containing the host material.

The first of the present invention is the following general formula (1)
(In the formula, Q ¹ and Q ² are the following formulas:
Ar ¹ and Ar ² are groups independently selected from the group consisting of an aryl group which may have a substituent and a heteroaryl group which may have a substituent, R is a group independently selected from the group consisting of an alkyl group, an aryl group which may have a substituent, or a heteroaryl group which may have a substituent)
It is related with the 3, 6- disubstituted carbazole derivative shown by these.
The second of the present invention is the following general formula (2)
(In the formula, Q ¹ and Q ² are the following formulas:
Ar ¹ and Ar ² are groups independently selected from the group consisting of an aryl group which may have a substituent and a heteroaryl group which may have a substituent.
It is related with the 3, 6- disubstituted carbazole derivative shown by these.
A third aspect of the present invention relates to a host material comprising the 3,6-disubstituted carbazole derivative according to claim 1 or 2.
A fourth aspect of the present invention relates to an organic EL device characterized in that the 3,6-disubstituted carbazole derivative according to claim 1 or 2 is used.
A fifth aspect of the present invention relates to an organic EL device characterized in that the 3,6-disubstituted carbazole derivative according to claim 1 or 2 is used for a light emitting layer.
A sixth aspect of the present invention relates to the organic EL element according to claim 4 or 5, wherein a phosphorescent material is used as a light emitting material used for a light emitting layer.
A seventh aspect of the present invention relates to the organic EL device according to claim 6, wherein a phosphorescent material that emits blue light having an emission peak wavelength shorter than 480 nm is used as the light emitting material.

  R in the general formula (1) of the present invention is an aryl group which may have an alkyl group, a substituent (which may include an alkyl group, an alkoxy group, an alkylamino group, etc.) or The heteroaryl group which may have a substituent can be mentioned. The alkyl in the alkyl group, alkoxy group or alkylamino group is preferably a linear or branched alkyl group having 1 to 6 carbon atoms. That is, methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, n-amyl, iso-amyl, n-hexyl, iso-hexyl and the like can be mentioned. As aryl groups, phenyl, biphenyl, terphenyl, quarterphenyl, naphthyl, anthranyl, phenanthrenyl, tetracene, tetraphen, etc., and for heteroaryl groups, thienyl, pyridyl, pyrimidyl, pyrazyl, quinolyl, isoquinolyl, benzo [b] thiophenyl , Cinnolyl, quinoxalyl and the like.

Examples of the aryl group that may have a substituent in Ar ¹ and Ar ² include phenyl, biphenyl, terphenyl, quarterphenyl, naphthyl, anthranyl, phenanthorenyl, tetracene, and tetraphen. Examples of the heteroaryl group which may have a substituent include thienyl, pyridyl, pyrimidyl, pyrazyl, quinolyl, isoquinolyl, benzo [b] thiophenyl, cinnolyl, quinoxalyl and the like. Examples of the substituent include a linear or branched alkyl group having 1 to 6 carbon atoms, an alkoxy group, and an alkylamino group, and an alkyl group is particularly preferable, and examples thereof include methyl, ethyl, n -Propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, n-amyl, iso-amyl, n-hexyl, iso-hexyl and the like.

The compound of the present invention can be produced by the following reaction.
In the above formula, R is an alkyl group, a group independently selected from the group consisting of an aryl group or a heteroaryl group which may have a substituent, and Ar ¹ and Ar ^{2 each} have a substituent. Each group may be independently selected from the group consisting of an aryl group and a heteroaryl group. X is a halogen.

The production method of the compound of the present invention will be specifically described.
The first reaction of the present invention is a reaction in which N-substituted-3,6-dihalocarbazole is lithiated (lithiated) and then coupled with a halogenated disubstituted phosphine. The solvent used in this reaction is not particularly limited as long as it does not react with the organolithium compound. For example, ether solvents such as diethyl ether, 1,4-dioxane, tetrahydrofuran and the like are preferable. Examples of the halogenated disubstituted phosphine include diphenylchlorophosphine.
Regarding the reaction temperature, when lithiation (lithiation) is carried out at 20 to 25 ° C. such as room temperature, a reductive elimination reaction in which the lithium metal once bound is released occurs, it is preferable to react at a low temperature. In general, it is suitable to react at −60 to −80 ° C. which can be cooled in a dry ice bath.
The second reaction is a reaction in which the obtained diphosphine compound is converted to phosphooxide with an oxidizing agent. The solvent used in this reaction is not particularly limited as long as the solvent itself does not undergo oxidation. Halogen-based solvents such as dichloromethane, chloroform, dichloroethane and chlorobenzene are preferred. As the oxidizing agent to be used, hydrogen peroxide, benzoyl peroxide, metachloroperbenzoic acid and the like can be used, but 30% hydrogen peroxide water is preferable in consideration of post-treatment. As for the reaction temperature, when heated, the reaction runs away and explodes. In addition, since it takes time for the reaction to cool, it is preferable to react at a room temperature, that is, a mild condition of 20 to 25 ° C.

Specific examples of the compound of the present invention are illustrated below.

The novel 3,6-disubstituted carbazole derivative of the present invention is suitable as a host material since the hole transport ability and the electron transport ability are confirmed. Moreover, since it has a wide energy level, it can be used as a host material for a phosphorescent material.

When the novel 3,6-disubstituted carbazole derivative of the present invention is used for organic electroluminescence, it is preferably used in combination with a suitable light emitting material.

  Next, the organic electroluminescence element of the present invention will be described. The organic EL device of the present invention is a device in which multiple organic compounds having respective functions are provided between an anode and a cathode, and at least one of the organic compound layers is a 3,6-disubstituted carbazole derivative of the present invention. It consists of a layer containing. The host layer and the light-emitting layer contain a light-emitting material, and in addition, the purpose is to transport holes injected from the anode or electrons injected from the cathode to the light-emitting material. It is preferable to use the compound of the present invention for this host layer, but it can also be used by mixing with an existing host material. Examples of the configuration of a multilayer organic EL element having a function include, for example, ITO / hole transport layer (hole transport layer) / light emitting layer (light emitting material + host material) / electron transport layer / cathode, ITO / hole transport. Layer / light emitting layer (light emitting material + host material) / electron transport layer / electron injection layer / cathode, ITO / hole transport layer / light emitting layer (light emitting material + host material) / hole block layer / electron transport layer / cathode, ITO / Hole transport layer / light emitting layer (light emitting material + host material) / hole block layer / electron transport layer / electron injection layer / cathode, ITO / hole injection layer / hole transport layer / light emitting layer (light emitting material + host material) / hole block A layer / electron transport layer / electron injection layer / a cathode having a multilayer structure such as a cathode. Moreover, you may have a sealing layer on a cathode as needed.

  Each of the hole transport layer, the electron transport layer, and the light emitting layer may have a single layer structure or a multilayer structure. In addition, the hole transport layer and the electron transport layer should be provided separately with a layer responsible for the injection function (hole injection layer and electron injection layer) and a layer responsible for the transport function (hole transport layer and electron transport layer). You can also.

  The organic electroluminescence element of the present invention is not limited to the above configuration example, and can have various configurations. If necessary, a layer in which a hole transport component and a light emitting layer component or an electron transport layer component and a light emitting layer component are mixed may be provided.

  Hereinafter, the constituent elements of the organic electroluminescence device of the present invention will be described by taking as an example the device configuration comprising anode / hole transport layer / light emitting layer (light emitting material + host material) / electron transport layer / cathode. The organic electroluminescence device of the present invention is preferably supported on a substrate.

  There is no restriction | limiting in particular about the raw material of a board | substrate, What is necessary is just used conventionally for the conventional organic electroluminescent element, For example, what consists of glass, quartz glass, a transparent plastic etc. can be used.

As an anode of the organic electroluminescence device of the present invention, an electrode material may be a single metal having a high work function (4 eV or more), an alloy of metals having a high work function (4 eV or more), a conductive substance, or a mixture thereof. preferable. Specific examples of such electrode materials include metals such as gold, silver, and copper, conductive transparent materials such as ITO (indium-tin oxide), tin oxide (SnO ₂ ), and zinc oxide (ZnO), polypyrrole, and polythiophene. Examples thereof include conductive polymer materials such as For the anode, these electrode materials can be formed by a method such as vapor deposition, sputtering, or coating. The sheet electrical resistance of the anode is preferably several hundred Ω / cm ² or less. The thickness of the anode depends on the material, but is generally about 5 to 1,000 nm, preferably 10 to 500 nm.

As the cathode, an electrode material is preferably a single metal having a low work function (4 eV or less), an alloy of metals having a low work function (4 eV or less), a conductive substance, or a mixture thereof. Specific examples of such electrode materials include lithium, lithium-indium alloy, sodium, sodium-potassium alloy, magnesium, magnesium-silver alloy, magnesium-indium alloy, aluminum, aluminum-lithium alloy, and aluminum-magnesium alloy. Can be mentioned. 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 electrical resistance of the cathode is preferably several hundred Ω / cm ² or less. The thickness of the cathode depends on the material, but is generally about 5 to 1,000 nm, preferably 10 to 500 nm. In order to efficiently extract light emitted from the organic EL device of the present invention, at least one of the anode and the cathode is preferably transparent or translucent.

The hole transport layer of the organic electroluminescence device of the present invention is made of a hole transfer compound and has a function of transferring holes injected from the anode to the light emitting layer. A hole transport material having a hole mobility of at least 10 ⁻⁶ cm ² / V · sec when a hole transport compound is disposed between two electrodes to which an electric field is applied and holes are injected from an anode Is preferred. The hole transport material used for the hole transport layer of the organic electroluminescence device of the present invention is not particularly limited as long as it has the above-mentioned preferable performance. Any one of materials conventionally used as hole charge injection materials in photoconductive materials and known materials used in hole transport layers of organic electroluminescent elements can be selected and used. .

Examples of the hole transport material include phthalocyanine derivatives such as copper phthalocyanine, N, N, N ′, N′-tetraphenyl-1,4-phenylenediamine, and N, N′-di (m-tolyl) -N. , N′-diphenyl-4,4-diaminophenyl (TPD), N, N′-di (1-naphthyl) -N, N′-diphenyl-4,4-diaminophenyl (α-NPD), etc. Examples thereof include amine derivatives, polyphenylenediamine derivatives, polythiophene derivatives, and water-soluble PEDOT-PSS (polyethylenedioxathiophene-polystyrenesulfonic acid). The hole transport layer may be composed of one or more of these other hole transport compounds, and a hole transport layer composed of a compound different from the hole transport material is laminated. Things can be used.
Examples of the hole injection material include PEDOT-PSS (polymer mixture) and DNTPD represented by the following chemical formula.

Examples of the hole transport material include TPD, DTASi, α-NPD, and the like represented by the following chemical formula.

  There is no restriction | limiting in particular about the light emitting layer of the organic electroluminescent element of this invention, Arbitrary things can be selected and used for a well-known material.

Examples of the light-emitting material include perylene derivatives, naphthacene derivatives, quinacridone derivatives, coumarin derivatives (eg, coumarin 1, coumarin 540, coumarin 545, etc.), pyran derivatives (eg, DCM-1, DCM-2, DCJTB, etc.), organometallic complexes, such as Fluorescent materials such as tris (8-hydroxyquinolinolato) aluminum complex (Alq ₃ ), tris (4-methyl-8-hydroxyquinolinolato) aluminum complex (Almq ₃ ) and [2- (4,6-difluorophenyl ) Pyridyl-N, C2 ′] iridium (III) picolylate (FIrpic), tris {1- [4- (trifluoromethyl) phenyl] -1H-pyrazolate-N, C2 ′} iridium (III) (Irtfmpppz ₃ ), Bis [2- (4 ′, 6′-difluorophenyl) pyridy DOO -N, C2 '] iridium (III) tetrakis (1-pyrazolyl) borate (FIr6), tris (2-phenylpyridinato) iridium (III) (Irppy ₃₎ and the like phosphorescent material such as .

  The light emitting layer is preferably formed of a host material and a guest material (dopant) [Appl. Phys. Lett. , 65 3610 (1989)]. In particular, when a phosphorescent material is used for the light emitting layer, it is necessary to use a host material, and it is preferable to use the novel 3,6-disubstituted carbazole derivative of the present invention as the host material used at this time. However, conventional host materials such as 4,4'-di (N-carbazolyl) -1,1'-biphenyl (CBP), 1,4-di (N-carbazolyl) benzene-2,2'-di [4 ″-(N-carbazolyl) phenyl] -1,1′-biphenyl (4CzPBP) or the like can also be used.

The guest material (dopant) is preferably 0.01 to 40% by weight, more preferably 0.1 to 20% by weight with respect to the host material. Examples of guest materials include conventionally known FIrpic, Irppy ₃ , FIr 6 and the like shown below.

  Conventional materials can be used as the material for the electron transport layer of the organic electroluminescent device of the present invention. Although this thing can be used independently, you may use together with another electron transport material.

Examples of the electron transport material used in the organic electroluminescence device of the present invention include quinoline complexes such as tris (8-hydroxyquinolinolato) aluminum complex (Alq ₃ ), 1-N-phenyl-2- (p- Triazine derivatives such as biphenylyl) -5- (p-tert-butylphenyl) -1,3,5-triazine (TAZ), 1,4-di (1,10-phenanthrolin-2-yl) benzene (DPB) And phenanthroline derivatives such as
Particularly preferable examples of the electron transport material include Alq ₃ , TAZ, and DPB represented by the following chemical formula.

In the organic electroluminescence device of the present invention, an electron injection layer composed of a conductor may be further provided between the cathode and the organic layer for the purpose of further improving the electron injection property. As the conductor used here, it is preferable to use at least one metal compound selected from alkali metal halides, alkaline earth metal halides, and alkali metal organic complexes. Examples of the alkali metal halide include lithium fluoride, sodium fluoride, potassium fluoride, cesium fluoride, and lithium chloride. Examples of the alkaline earth metal halide include magnesium fluoride, calcium fluoride, barium fluoride, and strontium fluoride. Examples of the alkali metal organic complex include 8-hydroxyquinolinolatolithium and 8-hydroxyquinolinolatocesium.
Moreover, the lithium complex (LiPB) of a phenanthroline derivative according to Japanese Patent Application No. 2006-292032 of the present applicant and the lithium complex (LiPP) of phenoxypyridine listed in Japanese Patent Application No. 2007-29695 can also be used.

  The method for forming the hole transport layer is not particularly limited. For example, a dry film forming method (for example, a vacuum vapor deposition method, an ionization vapor deposition method) or a wet film forming method [a solvent coating method (for example, a spin coating method, a casting method, an ink jet method, etc.)] can be used. For the novel 3,6-disubstituted carbazole derivative of the present invention as a host material that can also be used in the light emitting layer, it is preferable to use a dry film forming method (for example, a vacuum deposition method, an ionization deposition method, etc.). The film formation of the electron transport layer is limited to a dry film formation method (for example, a vacuum vapor deposition method, an ionization vapor deposition method, etc.) because the lower layer may be eluted when the wet film formation method is used. For the production of the element, the above film forming method may be used in combination.

When forming each layer such as a hole transport layer, a light emitting layer, and an electron transport layer by a vacuum deposition method, the vacuum deposition conditions are not particularly limited. Usually, under a vacuum of about 10 ⁻⁵ Torr or less, a boat temperature (deposition source temperature) of about 50 to 500 ° C., a substrate temperature of about −50 to 300 ° C., and 0.01 to 50 nm / sec. Vapor deposition is preferred. When each of the hole transport layer, the light emitting layer, and the electron transport layer is formed using a plurality of compounds, it is preferable to co-evaporate the boats containing the compounds while controlling the temperatures of the boats.

  When forming the hole transport layer by a solvent coating method, the components constituting each layer are dissolved or dispersed in a solvent to obtain a coating solution. Solvents include hydrocarbon solvents (eg, heptane, toluene, xylene, cyclohexane, etc.), ketone solvents (eg, acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), halogen solvents (eg, dichloromethane, chloroform, chlorobenzene, dichlorobenzene, etc.) Ester solvents (eg, ethyl acetate, butyl acetate, etc.), alcohol solvents (eg, methanol, ethanol, butanol, methyl cellosolve, ethyl cellosolve, etc.), ether solvents (eg, dibutyl ether, tetrahydrofuran, 1,4-dioxane, 1 , 2-dimethoxyethane, etc.), aprotic solvents (eg, N, N′-dimethylacetamide, dimethyl sulfoxide, etc.), water and the like. The solvent may be used alone, or a plurality of solvents may be used in combination.

  The thickness of each layer such as the hole transport layer, the light emitting layer, and the electron transport layer is not particularly limited, but is usually 5 to 5,000 nm.

  The organic electroluminescence device of the present invention can be protected by providing a protective layer (sealing layer) for the purpose of blocking contact with oxygen, moisture, etc., or by enclosing the device in an inert material. Examples of the inert substance include paraffin, silicon oil, and fluorocarbon. Examples of the material used for the protective layer include fluororesin, epoxy resin, silicone resin, polyester, polycarbonate, and photocurable resin.

  The organic electroluminescence device of the present invention can be used as a normal DC drive device. When a DC voltage is applied, light emission is usually observed when about 1.5 to 20 V is applied with the positive polarity of the anode and the negative polarity of the cathode. The organic electroluminescence device of the present invention can also be used as an AC drive device. When an AC voltage is applied, light is emitted when the anode is in a positive state and the cathode is in a negative state. The organic electroluminescence element of the present invention is, for example, a flat light emitter such as an electrophotographic photosensitive member or a flat panel display, a copying machine, a printer, a backlight of a liquid crystal display, a light source such as an instrument, various light emitting elements, various display devices, and various signs. It can be used for various sensors and various accessories.

  12 to 21 show examples of preferable cross-sectional views of the organic electroluminescence element of the present invention.

  FIG. 13 is a cross-sectional view showing an example of the organic electroluminescence element of the present invention. FIG. 13 shows a configuration in which an anode 2, a hole transport layer 5, a light emitting layer 3, an electron transport layer 6 and a cathode 4 are sequentially provided on a substrate 1. This is a separation of the functions of carrier transport and light emission, and the degree of freedom in material selection increases, so that the efficiency of light emission and the degree of freedom in light emission color increase.

  FIG. 14 is a cross-sectional view showing another example of the organic electroluminescence element of the present invention. FIG. 14 shows a structure in which an anode 2, a hole injection layer 7, a hole transport layer 5, a light emitting layer 3, an electron transport layer 6 and a cathode 4 are sequentially provided on a substrate 1. In this case, the provision of the hole injection layer 7 improves the adhesion between the anode 2 and the hole transport layer 5, improves the injection of holes from the anode, and is effective in lowering the voltage of the light emitting element.

  FIG. 15 is a cross-sectional view showing another example of the organic electroluminescence element of the present invention. FIG. 15 shows a configuration in which an anode 2, a hole transport layer 5, a light emitting layer 3, an electron transport layer 6, an electron injection layer 8 and a cathode 4 are sequentially provided on a substrate 1. In this case, injection of electrons from the cathode 4 is improved, which is effective for lowering the voltage of the light emitting element.

  FIG. 16 is a cross-sectional view showing another example of the organic electroluminescence element of the present invention. FIG. 16 shows a configuration in which an anode 2, a hole injection layer 7, a hole transport layer 5, a light emitting layer 3, an electron transport layer 6, an electron injection layer 8 and a cathode 4 are sequentially provided on a substrate 1. In this case, the injection of holes from the anode 2 is improved and the injection of electrons from the cathode 4 is improved, which is the most effective for driving at a low voltage.

  17 to 21 are sectional views of the device in which the hole blocking layer 9 is inserted. The hole blocking layer 9 has an effect of preventing holes injected from the anode or excitons generated by recombination in the light emitting layer 3 from escaping to the cathode 4 and improving the light emission efficiency of the organic electroluminescence device. Is effective. The hole blocking layer 9 can be inserted between the light emitting layer 3 and the cathode 4, between the light emitting layer 3 and the electron transport layer 6, or between the light emitting layer 3 and the electron injection layer 8. This is a case where it is provided between the light emitting layer 3 and the electron transport layer 6.

  17 to 21, each of the hole transport layer 5, the hole injection layer 7, the electron transport layer 6, the electron injection layer 8, the light emitting layer 3, and the hole blocking layer 9 may have a single layer structure or a multilayer structure. It may be a structure.

  12 to 21 are basic device configurations to the last, and the configuration of the organic electroluminescence device using the compound of the present invention is not limited to this.

Examples of the electron injecting material used for the electron injecting layer include the compounds according to Japanese Patent Application No. 2006-292032 of the present applicant, for example, the following compound group.

  The novel 3,6-disubstituted carbazole derivative of the present invention has a very large hole and electron transport capability compared to conventional host materials. In addition, the film formation stability during vapor deposition is high and crystallization is unlikely to occur. Therefore, the novel 3,6-disubstituted carbazole derivative of the present invention is extremely important industrially.

  Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited thereto.

Example 1
Synthesis of 3,6-bis (diphenylphosphine oxide) -9-phenylcarbazole (abbreviation CzDPO) 1) Synthesis of 3,6-bis (diphenylphosphine) -9-phenylcarbazole (abbreviation CzDP)
Under a nitrogen stream, 3,6-dibromo-9-phenylcarbazole and tetrahydrofuran (THF) were placed in an eggplant flask, and n-butyllithium (n-BuLi) was added and reacted at -78 ° C for 3 hours. Then, diphenylchlorophosphine (PPh ₂ Cl) was added and reacted for 3 hours. After completion of the reaction, the precipitate was filtered and washed with hexane and water to obtain a white solid. Table 1 summarizes the raw material charge ratio and the CzDP yield (yield).
2) Synthesis of 3,6-bis (diphenylphosphine oxide) -9-phenylcarbazole (abbreviation CzDPO)

3,6-bis (diphenylphosphine) -9-phenylcarbazole, dichloromethane and 35% aqueous hydrogen peroxide were added to an eggplant flask and reacted for 24 hours. After completion of the reaction, extraction was performed using ethyl acetate and brine, and the solvent was removed using an evaporator to obtain a white solid. Identification was performed by ¹ H-NMR. Table 2 summarizes the raw material charge ratio and the yield (yield) of CzDPO.
FIG. 1 shows a ¹ H-NMR chart of CzDPO.

Example 2
Evaluation of thermal properties of 3,6-bis (diphenylphosphine oxide) -9-phenylcarbazole (CzDPO) The thermal decomposition temperature, melting point and glass transition point of CzDPO were measured. The thermal decomposition temperature was measured at a heating rate of 10 ° C./min using a calorimetric analyzer (TG / TGA diamond manufactured by PerkinElmer). The melting point and glass transition point were measured at a heating rate of 10 ° C./min using a differential scanning calorimeter (DSC manufactured by PerkinElmer).
Table 3 shows the measurement results of the melting point, glass transition temperature, and decomposition temperature of CzDPO.
1) The decomposition temperature Td of 5% is a temperature at which a 5% weight loss of a sample appears due to thermal decomposition.
FIG. 2 shows the results of DSC measurement of CzDPO. In the figure, Tg is the glass transition temperature, and the peak portion on the right side shows the melting point of this compound.

Example 3
Evaluation of optical properties and electrochemical properties of 3,6-bis (diphenylphosphine oxide) -9-phenylcarbazole (CzDPO) A film was prepared by depositing CzDPO on a quartz substrate. The UV-vis absorption spectrum and fluorescence spectrum of this sample were measured.
The ionization potential (Ip) of the film deposited on the ITO substrate was measured with a photoelectron analyzer (AC-3). And the energy gap (Eg) was estimated from the absorption edge of the UV-vis absorption spectrum, and the electron affinity (Ea) was calculated.
Table 4 shows the electrochemical properties of CzDPO.
FIG. 3 shows a UV absorption curve of CzDPO, and FIG. 4 shows a CzDPO excitation light and PL spectrum curve.

Examples 4, 5, 6 and 7
Tris (4-benzonitrile-2-yl-1H-3,5-dimethylpyrazole) iridium (III) complex [abbreviation fac-Ir (dmpppzpCN) ₃ ] (special) using CzDPO synthesized in Example 1 as a light emitting layer host. Devices described in Japanese Patent Application No. 2008-73944) were used as dopants and evaluated. In Example 7, a device using tris (4-benzonitrile-2-yl-1H-pyrazole) iridium (III) complex [abbreviation fac-Ir (ppzpCN) ₃ ] as a dopant was prepared and evaluated in the same manner. .
The compounds used are as follows.
TAPC is N- {4- [1- [4- (di-p-tolylamino) phenyl] cyclohexyl] phenyl} -4-methyl-Np-tolylbenzenamine, BMPyPB is 1,3-bis [3, Abbreviation for 5-di (pyridin-3-yl) phenyl] benzene.
The created device configuration is as follows.
Element structure:
Example 4
Device 1: ITO / MCC-PC1020 (20 nm) / TAPC (20 nm) / CzDPO: fac-Ir (dmpppzCN) ₃ 15 wt% (40 nm) / BMPyPB (20 nm) / LiF (0.5 nm) / Al (100 nm)
Example 5
Device 2: ITO / MCC-PC1020 (20 nm) / TAPC (20 nm) / CzDPO: fac-Ir (dmpppzpCN) ₃ 15 wt% (20 nm) / BMPyPB (40 nm) / LiF (0.5 nm) / Al (100 nm)
Example 6
Device 3: ITO / MCC-PC1020 (20 nm) / TAPC (20 nm) / CzDPO: fac-Ir (dmpppzpCN) ₃ 15 wt% (10 nm) / BMPyPB (50 nm) / LiF (0.5 nm) / Al (100 nm)
Example 7
Ref1: ITO / MCC-PC1020 (Mitsubishi Chemical Corporation, trade name of hole injection material) (20 nm) / TAPC (20 nm) / CzDPO: fac-Ir (ppzpCN) ₃ 15 wt% (40 nm) / BMPyPB (20 nm) / LiF ( 0.5nm) / Al (100nm)
The energy diagram of these elements is shown in Figure 5,
The electroluminescence (EL) spectrum is shown in FIG. 6 (at 0.05 mA) and FIG. 7 (at 1.0 mA).
The current density vs. voltage characteristics are shown in FIG.
The luminance-voltage characteristics are shown in FIG.
The current efficiency-current density characteristics are shown in FIG.
The quantum efficiency-current density is shown in FIG.
Each is shown.
As seen in FIGS. 8 to 11, it is clear that the performance of the organic EL elements of Examples 4 to 6 is extremely superior to that of Example 7.

¹ H-NMR of CzDPO synthesized in Example 1 is shown. The DSC measurement result of CzDPO synthesize | combined in Example 1 is shown. The UV absorption curve of CzDPO is shown. The excitation light and PL spectrum curve of CzDPO are shown. The energy diagram of the organic electroluminescent element (organic EL element) of Examples 4-6 and Example 7 is shown. The electroluminescence (EL) spectrum (at the time of 0.05 mA) of the organic electroluminescent element (organic EL element) of Examples 4-6 is shown. The electroluminescent (EL) spectrum (at the time of 1.0 mA) of the organic electroluminescent element (organic EL element) of Examples 4-6 is shown. The current density-voltage characteristic of the organic electroluminescent element (organic EL element) of Examples 4-6 and Example 7 is shown. The brightness | luminance-voltage characteristic of the organic electroluminescent element (organic EL element) of Examples 4-6 and Example 7 is shown. The current efficiency-current density characteristic of the organic electroluminescent element (organic EL element) of Examples 4 to 6 and Example 7 is shown. The quantum efficiency-electric current density of the organic electroluminescent element (organic EL element) of Examples 4-6 and Example 7 is shown. It is sectional drawing which shows an example of the organic electroluminescent element in this invention. It is sectional drawing which shows an example of the organic electroluminescent element in this invention. It is sectional drawing which shows an example of the organic electroluminescent element in this invention. It is sectional drawing which shows an example of the organic electroluminescent element in this invention. It is sectional drawing which shows an example of the organic electroluminescent element in this invention. It is sectional drawing which shows an example of the organic electroluminescent element in this invention. It is sectional drawing which shows an example of the organic electroluminescent element in this invention. It is sectional drawing which shows an example of the organic electroluminescent element in this invention. It is sectional drawing which shows an example of the organic electroluminescent element in this invention. It is sectional drawing which shows an example of the organic electroluminescent element in this invention.

Explanation of symbols

1 Substrate 2 Anode (ITO)
3 Light emitting layer 4 Cathode 5 Hole transport layer (hole transport layer)
6 Electron transport layer 7 Hole injection layer (hole injection layer)
8 Electron injection layer 9 Hole blocking layer (hole blocking layer)

Claims (7)

The following general formula (1)
(In the formula, Q ¹ and Q ² are the following formulas:
Ar ¹ and Ar ² are groups independently selected from the group consisting of an aryl group which may have a substituent and a heteroaryl group which may have a substituent, R is a group independently selected from the group consisting of an alkyl group, an aryl group which may have a substituent, or a heteroaryl group which may have a substituent)
A 3,6-disubstituted carbazole derivative represented by the formula: The following general formula (2)
(In the formula, Q ¹ and Q ² are the following formulas:
Ar ¹ and Ar ² are groups independently selected from the group consisting of an aryl group which may have a substituent and a heteroaryl group which may have a substituent.
A 3,6-disubstituted carbazole derivative represented by the formula:   A host material comprising the 3,6-disubstituted carbazole derivative according to claim 1 or 2.   An organic EL device comprising the 3,6-disubstituted carbazole derivative according to claim 1 or 2.   3. An organic EL device using the 3,6-disubstituted carbazole derivative according to claim 1 for a light emitting layer.   6. The organic EL device according to claim 4, wherein a phosphorescent material is used as a light emitting material used for the light emitting layer.   The organic EL element according to claim 6, wherein a phosphorescent material exhibiting blue light emission having an emission peak wavelength shorter than 480 nm is used as the light emitting material.