JP2005190993A - Organic electron function material and method for utilizing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electron function material having a photo-electron conversion function, oxidized and reduced, forming an amorphous film by itself, and also having high glass transition temperature and high stability. <P>SOLUTION: The organic electron function material is made of a kind of tris-(arylamino)benzene expressed by the formula (1), of which, deviation of 50 times of peak current of a cyclic curve at a sweeping speed of 20 mV/sec. at cyclic voltammetry is within ±10% of the mean value of a peak current. The organic electron material has a structure formed by substituting a stable substituent like an alkyl group or cycloalkyl group, for a chemical active point of a terminal end of each aryl group in the arylamino group, preferably carbon atom at para-position of phenyl group. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an organic electronic functional material and its use. In particular, it is composed of tris (arylamino) benzenes, and is excellent in the stability of repeated redox, so that it can be suitably used as, for example, a hole transport agent. Organic electrofunctional material that can be used, and its use, for example, the above-described hole transport agent made of such an organic electronic functional material, and further, an organic electroluminescence device comprising a hole transport layer made of the hole transport agent About.

  In recent years, various organic compounds such as light-emitting elements and semiconductors that use an organic compound as an electron functional material, such as a hole transport agent, which has an optical / electronic conversion function and a reversible redox function and can form an amorphous film by itself. Electronic devices are attracting attention. In order to obtain an amorphous film made of such an organic compound, a method of forming an amorphous film by dissolving a binder resin such as polycarbonate and the organic compound in an organic solvent, coating and drying (see Patent Document 1) In the case of polynuclear aromatic tertiary amines called so-called “starburst” molecules capable of forming an amorphous film by themselves at room temperature, a method of forming an amorphous film by depositing it on a substrate Etc. are known (see Patent Document 2).

  Among such methods, according to the method using a binder resin, in the formed amorphous film, the organic compound is diluted with the binder resin and is affected by this, so that the function of the original electronic functional material is improved. It cannot be fully used. Also, even if an amorphous film stable at room temperature can be formed with the help of a binder resin, the low molecular weight organic compound itself has a low glass transition temperature, poor heat resistance, and there are problems in the stability and life of the amorphous film. is there.

  Under such circumstances, as described above, the polynuclear aromatic tertiary amines called “starburst” molecules can form an amorphous film by themselves at room temperature. ,Attention has been paid. This “starburst” molecule is divided into three groups according to its molecular structure: triphenylamine skeleton (triphenylamines), triaminobenzene skeleton (triaminobenzenes) and triphenylbenzene skeleton. (Triphenylbenzenes).

  Examples of triphenylamines include 4,4 ′, 4 ″ -tris (N, N-diphenylamino) triphenylamine (TDATA) and 4,4 ′, 4 ″ -tris (N-phenyl-Nm-tolylamino). ) Triphenylamine (m-MTDATA) (see Patent Document 3) is known, and 4,4 ′, 4 ″ -tris (N- (2-naphthyl) -N-phenylamino) triphenylamine ( 2-TNATA) and the like are also known (see Patent Document 2) These triphenylamines are reversible in oxidation and reduction, and can form an amorphous film by a vapor deposition method. MTDATA has difficulty in heat resistance, and TNATA has a glass transition temperature of around 110 ° C., which is excellent in heat resistance but is easy to crystallize. There is a problem with sex.

  Examples of triphenylbenzenes include 1,3,5-tris (4-N, N-diphenylaminophenyl) benzene (TDAPB) and 1,3,5-tris (4- (N-tolyl-N-phenylaminophenyl). ) Benzene (MTDAPB) is known (see Non-Patent Document 1) These triphenylbenzenes form an amorphous film and have an oxidation potential of 0.6 to 0.7 V, but the oxidation-reduction is irreversible. Therefore, it is poor in practicality as an electronic functional material such as a hole transport agent, while 1,3,5-tris (N-methylphenyl-N-phenylamino) benzene (MTDAB) is used as a triaminobenzene. These oxidation potentials are 0.6 to 0.7 V. However, since the oxidation-reduction is irreversible, similarly, the practicality as an organic electronic functional material is poor. .

  Furthermore, the present inventors have shown that 1,3 and 3 are organic compounds that are reversible in redox, have an oxidation potential in the range of 0.5 to 0.7 V, have excellent heat resistance, and can form an amorphous film by vapor deposition. , 5-Tris (N- (p-methylphenyl) -N- (1-naphthyl)) aminobenzene (p-MTPNAB) and 1,3,5-tris (N- (p-methylphenyl) -N- ( 4-biphenyl) amino) benzene (p-MTPBAB) (Japanese Patent Application No. 2003-077941) has been proposed.

  These p-MTPNAB and p-MTPBAB are reversible in redox, have a high oxidation potential, and have a high glass transition point of 87 ° C. and 98 ° C., respectively. Since the current at the peak tends to decrease, the stability and durability of the performance as an organic electronic functional material may not be sufficient.

On the other hand, hole transporting agents composed of polynuclear aromatic tertiary amines having a biphenyl skeleton are also conventionally known. Examples of such polynuclear aromatic tertiary amines include 4,4′-bis (N- (3-methylphenyl) -N-phenylamino) biphenyl (TPD), (see Patent Document 4), 4′-bis (N- (1-naphthyl) -N-phenylamino) biphenyl (α-NPD) and the like are known (for example, see Patent Document 5). The luminescent element requires a high drive voltage to operate it.
JP 11-174707 A Japanese Patent Laid-Open No. 08-291115 JP-A-01-224353 JP 10-090256 A JP 05-234681 A Bando Technical Report, No. 2, pages 9-18 (1998)

  The present invention has been made in order to solve the above-described problems in organic electronic functional materials, has an optical / electronic conversion function, is reversible in redox, and forms an amorphous film by itself. Another object of the present invention is to provide an organic electronic functional material having a high glass transition temperature and a small change in peak current value even in repeated redox, and thus excellent stability.

  According to the invention, the general formula (I)

Wherein A and B are the general formula (II)

(In the formula, R represents an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 5 or 6 carbon atoms, and n is 0, 1, 2, or 3.)
Which may be the same or different. )
In the cyclic voltammogram, the deviation of the peak current of the 50 cyclic curves at a sweep rate of 20 mV / sec is within ± 10% of the average value of the peak current. An organic electronic functional material is provided.

  Furthermore, according to this invention, the organic electroluminescent element which has a hole transport agent which consists of the said organic electronic functional material, and a hole transport layer containing such a hole transport agent is provided.

  The organic electronic functional material according to the present invention comprises tris (arylamino) benzenes represented by the above general formula (I), has reversible redox properties, a high oxidation potential, and a high glass transition point. Moreover, in addition to forming an amorphous film that is stable at room temperature by vapor deposition or the like, in particular, in a cyclic voltammogram showing reversibility of redox, a cyclic curve of 50 times at a sweep rate of 20 mV / sec. The deviation of the peak current is within ± 10% of the average value of the peak current, and according to the preferred embodiment, within ± 5%, and the reversibility of the redox is excellent. The initial performance can be maintained for a long time with little change. Thus, in various electronic devices such as organic electroluminescent elements, the presence of a hole transporting agent is It can be suitably used as an electromechanical functional material.

  The organic electronic functional material according to the present invention has the general formula (I)

Wherein A and B are the general formula (II)

(In the formula, R represents an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 5 or 6 carbon atoms, and n is 0, 1, 2, or 3.)
Which may be the same or different. )
It consists of tris (arylamino) benzenes represented by these.

  Accordingly, in the tris (arylamino) benzenes represented by the above general formula (I), the groups A and B are a phenyl group having the alkyl group or cycloalkyl group, and the alkyl group or cycloalkyl group on the terminal phenyl group. A terphenyl group having the alkyl group or cycloalkyl group at the terminal phenyl group, or a quater phenyl group having the alkyl group or cycloalkyl group at the terminal phenyl group, The groups A and B may be the same as each other or different from each other.

  In particular, according to the present invention, the tris (arylamino) benzene represented by the general formula (I) is a biphenylyl group in which the group A has the alkyl group or cycloalkyl group at the para position of the terminal phenyl group. And the group B is preferably a phenyl group having the above alkyl group or cycloalkyl group in the para position, and the organic electronic functional material composed of such tris (arylamino) benzenes has redox reversibility, oxidation Excellent balance in terms of electric potential and heat resistance.

  In the present invention, the alkyl group is, for example, a methyl, propyl, butyl, pentyl or hexyl group, and may be linear or branched. The cycloalkyl group is a cyclopentyl or cyclohexyl group.

  Among such tris (arylamino) benzenes, according to the present invention, the following formula (IV)

The organic electronic functional material consisting of 1,3,5-tris (N- (4′-methyl-4-biphenylyl) -N- (p-tolyl) amino) benzene represented by Since it is excellent, it can be suitably used as a hole transport agent in various electronic devices.

  Such 1,3,5-tris (N- (4′-methyl-4-biphenylyl) -N- (p-tolyl) amino) benzene is, for example, 1,3,3, as shown in the following scheme: It can be obtained by reacting 5-tris (p-tolyl) aminobenzene (V) with 4-iodo-4′-methylbiphenyl (VI).

  Thus, the organic electronic functional material according to the present invention, in tris (arylamino) benzenes, is a chemically active site at the terminal of each aryl group in each arylamino group, preferably in the para position of the phenyl group. Redox properties of tris (arylamino) benzenes, which are one of the “starburst” molecules, by replacing the carbon atom with a stable substituent such as the above alkyl group or cycloalkyl, and so on capping. In addition to ensuring a high oxidation potential and a high glass transition point, durability was imparted to repeated redox, thus succeeding in reducing changes in peak current in repeated redox. In an electronic device, it can be suitably used as a stable and durable organic electronic functional material.

  Organic electroluminescence elements have low voltage direct current drive, high efficiency, high luminance, and can be thinned, so that their practical use has been promoted as a display device in addition to a backlight and a lighting device in recent years.

  As shown in FIG. 1, for example, the organic electroluminescence element is formed by laminating an anode 2 made of a transparent electrode such as an ITO film (indium oxide-tin oxide film) on a transparent substrate 1 made of glass, for example. The hole injection layer 3a, the hole transport layer 3, the light emitting layer 4, and the cathode 5 made of a metal or a compound thereof are laminated in this order on the transparent electrode. The anode and cathode are connected to an external power source 6. In some cases, the hole injection layer 3a may be omitted, and an electron transport layer may be laminated between the light emitting layer and the cathode, and the conductive property may be provided between the anode and the hole transport layer. A polymer layer (buffer layer) may be laminated. In addition to these, organic electroluminescence elements having various configurations are known.

  The organic electroluminescence device according to the present invention is characterized in that it has a hole transporting layer using the above-described tris (arylamino) benzene represented by the general formula (I) as a hole transporting agent, The laminated structure is not particularly limited. The film thickness of the hole transport layer is usually about 10 to 200 nm.

  In the organic electroluminescence device having the laminated structure as described above, the hole transport layer is in close contact with the anode, and transports holes from the anode to the light emitting layer and blocks electrons, while The transport layer is in close contact with the cathode, and transports electrons from the cathode to the light emitting layer, where the electrons injected from the cathode and holes injected from the anode into the light emitting layer are recombined. Luminescence occurs and is emitted to the outside through the transparent electrode (anode) and the transparent substrate.

  In the organic electroluminescence device according to the present invention, conventionally known layers other than the hole transport layer, that is, a transparent substrate, an anode, a light emitting layer, an electron transport layer, and a cathode are appropriately used. Accordingly, for example, a transparent electrode made of indium oxide-tin oxide (ITO), tin oxide-indium oxide, or the like is used as the anode, and a single metal such as aluminum, magnesium, indium, silver, or an alloy thereof is used as the cathode. For example, an electrode made of an Al—Mg alloy, an Ag—Mg alloy, or a metal compound is used, and a glass substrate is usually used as the transparent substrate.

For example, tris (8-quinolinol) aluminum (Alq ₃ ) is used for the light emitting layer, and the film thickness is usually in the range of 10 to 200 nm. Moreover, the film thickness of an electron carrying layer is also the range of 10-200 nm normally, and when a conductive polymer layer is included, the film thickness is also the range of 10-200 nm normally.

  In the case where the organic electronic functional material according to the present invention is used as a hole transport agent, the energy gap between the anode and the hole transport layer is reduced to facilitate the transport of holes from the anode to the hole transport layer. A conventionally known hole injection layer using copper phthalocyanine (CuPC) as a hole injection agent may be provided between the anode and the hole transport layer.

  Furthermore, the organic electronic functional material according to the present invention is used as a hole transport agent and has the general formula (III).

(Wherein X and Y are aryl groups, which may be the same or different.)
In combination with tris (4- (N-N-diarylamino) phenyl) amines represented by the formula, an organic electroluminescence device exhibiting high luminance with a lower driving voltage can be obtained. That is, according to the present invention, in an organic electroluminescence element, hole injection using tris (4- (NN-diarylamino) phenyl) amine represented by the general formula (III) as a hole injecting agent. By laminating the layer and the hole transport layer using the organic electronic functional material according to the present invention as a hole transport agent, the voltage-luminance characteristics of the obtained organic electroluminescence device can be further improved.

Further, according to the present invention, according to the present invention, in the organic electroluminescence device, the tris (4- (N.N-diarylamino) phenyl) amine represented by the general formula (III) and the organic according to the present invention are used. You may form the positive hole transport layer which uses a uniform mixture with an electronic functional material as a positive hole transport agent.

Tris (4- (N-N-diarylamino) phenyl) represented by the above general formula (III)
In the amines, X and Y are aryl groups which may be the same or different from each other. Specific examples of such aryl groups include, for example, a phenyl group, o-, m- or p-tolyl group. 1- or 2-naphthyl group, 4-p-biphenylyl group, 4-p-terphenylyl group and the like.

  Therefore, as a specific example of the tris (4- (N.N-diarylamino) phenyl) amine, as described above, for example, 4,4 ′, 4 ″ -tris (N, N-diphenylamino) triphenyl Amine (TDATA), 4,4 ′, 4 ″ -tris (N-phenyl-Nm-tolylamino) triphenylamine (m-MTDATA), 4,4 ′, 4 ″ -tris (N- (2-naphthyl) ) -N-phenylamino) triphenylamine (2-TNATA) and the like, but is not limited thereto.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Example 1
(Preparation of 1,3,5-tris (p-tolyl) aminobenzene)
Phloroglucinol 11.8 g, p-toluidine 50 g, and iodine 0.5 g were charged into a 300 mL three-necked flask and heated and stirred at 150 ° C. in a nitrogen atmosphere. After completion of the reaction, the resulting reaction mixture was washed with methanol, hexane, and methanol in that order, and dried to give the desired 1,3,5-tris (p-tolyl) aminobenzene as a slightly reddish solid. 9 g was obtained. The yield was 86.5%.

(Preparation of 1,3,5-tris (N- (4′-methyl-4-biphenylyl) -N- (p-tolyl) amino) benzene (p-MBTAB))
2.0 g of 1,3,5-tris (p-tolyl) aminobenzene, 7.0 g of 4-iodo-4′-methylbiphenyl, 6.9 g of potassium carbonate, 1 g of copper powder and 18-crown-6 (1,4 , 7,10,13,16-hexaoxacyclooctadecane) 0.7 g together with 15 mL of the reaction solvent mesitylene was charged into a 100 mL volumetric glass flask and reacted at 170 ° C. for 15 hours in a nitrogen atmosphere. After completion of the reaction, the resulting reaction mixture was extracted with toluene, and this toluene solution was subjected to silica gel chromatography to fractionate the reaction product. The reaction product was purified by recrystallization, and then purified by sublimation to obtain the desired 1,3,5-tris (N- (4′-methyl-4-biphenylyl) -N- (p-tolyl) amino). Benzene (p-MBTAB) was obtained. The yield was 15.6%.

Elemental analysis value (%):
C H N
Calculated value 88.89 6.40 4.71
Measurement 88.69 6.55 4.76

Mass spectrometry: 892 (M ⁺ )

Differential scanning calorimetry (DSC)
As a sample, about 5 mg of p-MBTAB was weighed and once melted in a differential scanning calorimeter, and then cooled to room temperature at a rate of 50 ° C./min. became. Next, with reference to the aluminum plate, the thermal characteristics were measured at a heating rate of 5 ° C./min. As shown in FIG. 2 of the DSC chart, the glass transition point (Tg) was 103.4 ° C., the crystallization temperatures (Tc) were 138.7 ° C. and 180.1 ° C., and the melting point was 277.9 ° C. .

Cyclic voltammetry (CV):
p-MBTAB was dissolved in dichloromethane to adjust the concentration to 10 ⁻³ M. Using (n-C ₄ H ₉ ) ₄ NClO ₄ (0.1 M) as the supporting electrolyte and Ag / Ag ⁺ as the reference electrode, the redox characteristics were measured at a scan rate of 20 mV / sec. As shown in FIG. 3, the oxidation potential defined as the average value of the peak potential of the oxidation curve and the peak potential of the reduction curve is 0.49 V (vs Ag / Ag ⁺ ). Furthermore, the average value of the oxidation curve peak current is 2.565 × 10 ⁻⁶ A, the maximum value is 2.596 × 10 ⁻⁶ A, and the minimum value is 2.533 × 10 ⁻⁶ A. The deviation was slightly stable at ± 1.21%, and it was confirmed that the performance degradation due to repeated redox was extremely small.

Comparative Example 1
(Preparation of 1,3,5-tris (1-naphthyl) aminobenzene)
Phloroglucinol (4.4 g), 1-naphthylamine (25 g) and iodine (0.5 g) were charged into a 100 mL three-necked flask and reacted by heating and stirring at 140 ° C. for 4 hours in a nitrogen atmosphere. 3. After completion of the reaction, the obtained reaction mixture was washed with methanol, hexane and methanol in this order and dried to obtain the desired 1,3,5-tris (1-naphthyl) aminobenzene as a slightly reddish solid. 4 g was obtained. The yield was 25%.

(Preparation of 1,3,5-tris (N- (4-biphenylyl) -N- (1-naphthyl) amino) benzene (TBNAB))
1,3,5-tris (1-naphthyl) aminobenzene 2.0 g, 4-iodobiphenyl 5.0 g, potassium carbonate 3.7 g, copper powder 2 g and 18-crown-6 (1,4,7,10, 13,16-hexaoxacyclooctadecane) (0.3 g) was charged into a 100 mL glass flask together with 10 mL of the reaction solvent mesitylene, and reacted at 170 ° C. for 17 hours in a nitrogen atmosphere. After completion of the reaction, the resulting reaction mixture was extracted with toluene, and this toluene solution was subjected to silica gel chromatography to fractionate the reaction product. This reaction product was recrystallized from a toluene / hexane mixed solvent, dried, and further purified by sublimation to obtain the desired 1,3,5-tris (N- (4-biphenylyl) -N- (1-naphthyl). 1.2 g of amino) benzene (TBNAB) was obtained. The yield was 32%.

Elemental analysis value (%):
C H N
Calculated value 90.25 5.36 4.39
Measurement 89.96 5.44 4.32

Mass spectrometry: 957 (M ⁺ )

Differential scanning calorimetry (DSC)
As a sample, about 5 mg of TBNAB was weighed and once melted in a differential scanning calorimeter, and then cooled to room temperature at a rate of 50 ° C./min, but the sample did not crystallize and became an amorphous glass. . Next, with reference to the aluminum plate, the thermal characteristics were measured at a heating rate of 5 ° C./min. As shown in FIG. 4 of the DSC chart, the glass transition point (Tg) was 130 ° C., the crystallization temperature (Tc) was 204 ° C., and the melting point (Tm) was 271 ° C.

Cyclic voltammetry (CV):
TBNAB was dissolved in dichloromethane, and the redox characteristics were measured in the same manner as in Example 1. As shown in FIG. 5, the oxidation potential is 0.6 V (vs Ag / Ag ⁺ ), and reversibility is found in redox in 50 repeated measurements, but the average value of the oxidation curve peak current is 4.257. × 10 ⁻⁴ A, the maximum value was 4.687 × 10 ⁻⁴ A, the minimum value was 3.816 × 10 ⁻⁴ A, and the deviation was as large as ± 10.1%.

Example 2
A glass sheet coated with ITO on one side (manufactured by Yamato Vacuum Co., Ltd.) was subjected to ultrasonic cleaning using acetone and steam cleaning using methanol, and then irradiated with ultraviolet rays for 10 minutes using a low-pressure mercury lamp. Immediately thereafter, copper phthalocyanine (CuPC) was deposited on the ITO coating using a vacuum deposition apparatus to form a 20 nm thick hole injection layer, and then p-MBTAB was deposited thereon. A hole transport layer having a thickness of 40 nm was formed. Next, a 75 nm thick light emitting layer made of tris (8-quinolinol) aluminum (Alq ₃ ) is formed on the hole transport layer, and a 0.5 nm thick lithium fluoride layer and a 100 nm thick light emitting layer are further formed thereon. Aluminum layers were sequentially deposited and formed to form a cathode, thus obtaining an organic electroluminescence device.

The initial luminance of 1000 cd / m ² when a voltage was applied between the electrodes of the organic electroluminescence element was taken as 100%, and the subsequent change in luminance with time was examined. The results are shown in FIG. Further, a voltage was applied between the electrodes of the organic electroluminescence element, and the voltage-luminance characteristics were examined. The results are shown in FIG.

Comparative Example 2
In Example 2, instead of p-MBTAB, 1,3,5-tris (p-N-phenyl-Nm-tolyl) aminophenyl) benzene (m-MTDAPB) was used in the same manner. An organic electroluminescence device was obtained. The initial luminance of 1000 cd / m ² when a voltage was applied between the electrodes of the organic electroluminescence element was taken as 100%, and the subsequent change in luminance with time was examined. The results are shown in FIG.

  As shown in FIG. 6, the organic electroluminescence device having a hole transport layer using p-MBTAB as a hole transport agent according to the present invention is a positive electrode using m-MTDAPB as a hole transport agent for comparison. Compared to an organic electroluminescence device having a hole transport layer, it has excellent lifetime characteristics.

Example 3
A glass sheet coated with ITO on one side (manufactured by Yamato Vacuum Co., Ltd.) was subjected to ultrasonic cleaning using acetone and steam cleaning using methanol, and then irradiated with ultraviolet rays for 10 minutes using a low-pressure mercury lamp. Immediately thereafter, 4,4 ′, 4 ″ -tris (N- (2-naphthyl) -N-phenylamino) triphenylamine (2-TNATA) was added onto the ITO coating using a vacuum deposition apparatus. After vapor deposition to form a 50 nm thick hole injection layer, p-MBTAB was vapor deposited thereon to form a 10 nm thick hole transport layer. A light emitting layer having a thickness of 75 nm made of 8-quinolinol) aluminum (Alq ₃ ) is formed, and a lithium fluoride layer having a thickness of 0.5 nm and an Al layer having a thickness of 100 nm are further sequentially deposited thereon to form a cathode. Thus, an organic electroluminescence element was obtained.

  A voltage was applied between the electrodes of the organic electroluminescence element to examine the voltage-luminance characteristics. The results are shown in FIG.

Comparative Example 3
In Example 3, organic electroelectrolysis was carried out in the same manner except that 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (α-NPD) was used instead of p-MBTAB. A luminescence element was obtained. A voltage was applied between the electrodes of the organic electroluminescence element to examine the voltage-luminance characteristics. The results are shown in FIG.

Comparative Example 4
In Example 3, a 20-nm-thick hole injection layer made of copper phthalocyanine (CuPC) was formed instead of 2-TNATA, and 40-nm-thick holes made of α-NPD instead of p-MBTAB thereon An organic electroluminescence device was obtained in the same manner except that a transport layer was formed. A voltage was applied between the electrodes of the organic electroluminescence element, and the voltage-luminance characteristics of the organic electroluminescence element were examined. The results are shown in FIG.

  As is apparent from the results of FIG. 7, organic electroluminescence provided with a hole transport layer comprising p-MBTAB according to the present invention as a hole transport agent and a hole injection layer comprising a conventionally known hole inject agent. The device (Examples 2 and 3) is an organic electroluminescence device including a hole transport layer made of a conventionally known hole transport agent and a hole injection layer made of a conventionally known hole injecting agent. Compared to (Comparative Examples 3 and 4), when the applied voltage is the same, the luminance is higher.

  The organic electronic functional material according to the present invention forms a stable amorphous film by itself, has an oxidation potential in the range of 0.5 to 0.7 V, has a high glass transition temperature, and is stable in repeated redox. Therefore, in various electronic devices such as semiconductors and display elements, it can be suitably used as an organic electronic functional material such as a hole transport agent.

It is sectional drawing which shows an example of an organic electroluminescent element. Differential scanning calorimetry of 1,3,5-tris (N- (4′-methyl-4-biphenylyl) -N- (p-tolyl) amino) benzene (p-MBTAB) which is the organic electronic functional material of the present invention (DSC) Curve. In the 1,3,5-tris (N- (4′-methyl-4-biphenylyl) -N- (p-tolyl) amino) benzene (p-MBTAB) cyclic voltammogram which is the organic electronic functional material of the present invention is there. It is a differential scanning calorimetry (DSC) curve of 1,3,5-tris (N- (4-biphenylyl) -N- (1-naphthyl) amino) benzene (TBNAB) which is an organic electronic functional material as a comparative example. . It is a cyclic voltammogram of 1,3,5-tris (N- (4-biphenylyl) -N- (1-naphthyl) amino) benzene (TBNAB) which is an organic electronic functional material as a comparative example. An organic electronic functional material comprising 1,3,5-tris (N- (4′-methyl-4-biphenylyl) -N- (p-tolyl) amino) benzene (p-MBTAB) according to the present invention is used as a hole transport agent. Time-luminance characteristics (Example 2) of an organic electroluminescence device provided with a hole transport layer, and 1,3,5-tris (p-N-phenyl-Nm-tolyl) for a comparative example It is a graph which shows the time-luminance characteristic (comparative example 2) of an organic electroluminescent element provided with the positive hole transport layer which uses a phenyl) benzene (m-MTDAPB) as a positive hole transport agent. An organic electroluminescence device (Example 2) comprising a hole injection layer made of copper phthalocyanine and a hole transport layer made of an organic electronic functional material according to the present invention, a hole injection layer made of 2-TNATA, and a p- Organic electroluminescence device having a hole transport layer made of MBTAB (Example 3), hole injection layer made of 2-TNATA and 4,4′-bis [N- (1-naphthyl) -N-phenylamino] Organic electroluminescence device (Comparative Example 3) provided with a hole transport layer made of biphenyl (α-NPD), and organic electroluminescence device comprising a hole injection layer made of copper phthalocyanine and a hole transport layer made of α-NPD It is a graph which shows each voltage-luminance characteristic of (comparative example 4).

Explanation of symbols

1 ... Transparent substrate 2 ... Anode (transparent electrode)
3a ... hole injection layer 3 ... hole transport layer 4 ... light emitting layer 5 ... cathode 6 ... power source

Claims (6)

Formula (I)
Wherein A and B are the general formula (II)
(In the formula, R represents an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 5 or 6 carbon atoms, and n is 0, 1, 2, or 3.)
Which may be the same or different. )
In the cyclic voltammogram, the deviation of the peak current of the 50 cyclic curves at a sweep rate of 20 mV / sec is within ± 10% of the average value of the peak current. An organic electronic functional material characterized by being.   The group A is a biphenylyl group or a terphenylyl group having an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 5 or 6 carbon atoms in the terminal phenyl group, and the group B is an alkyl group having 1 to 6 carbon atoms. Or the organic electronic functional material of Claim 1 which consists of tris (arylamino) benzene which is a phenyl group which has a C5-C6 cycloalkyl group.   The organic electronic function according to claim 1, wherein the tris (arylamino) benzene is 1,3,5-tris (N- (4'-methyl-4-biphenylyl) -N- (p-tolyl) amino) benzene. material.   A hole transport agent comprising the organic electronic functional material according to claim 1.   The organic electroluminescent element which has a positive hole transport layer containing the positive hole transport agent of Claim 4. A hole transport layer comprising the hole transport agent according to claim 4 and a general formula (III)
(Wherein X and Y are aryl groups, which may be the same or different.)
The organic electroluminescent element provided with the positive hole injection layer containing the positive hole injection agent which consists of tris (4- (N, N- diarylamino) phenyl) amine represented by these.