JP2007070282A - Novel triarylboron derivative and organic electroluminescent device containing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel phosphorescence material, particularly a novel triarylboron derivative useful in forming an electron transport layer having a wide gap suitable for a blue phosphorescence material, and an organic electroluminescent device containing the same. <P>SOLUTION: The triarylboron derivative is represented by formula (1), and the organic electroluminescent device contains the same. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a novel triarylboron derivative useful for forming a wide-gap electron transport layer suitable for a novel phosphorescent material, particularly a blue phosphorescent material, and an organic electroluminescence device including the same.

  The organic EL element emits light when excitation energy generated by recombination of holes and electrons injected from an electrode is relaxed to a ground state through a light emission process. However, there are two types of excited states generated by recombination of holes and electrons, a singlet excited state and a triplet excited state, in a ratio of 1: 3. In many cases, a fluorescent material utilizing light emission from a singlet excited state has been used as a light emitting material, and therefore, the internal quantum efficiency is 25% at the maximum. The quantum efficiency was the theoretical limit of 5%.

  In recent years, improvement in luminous efficiency has been reported by using light emission from a triplet excited state, that is, phosphorescence emission, using a complex compound utilizing a heavy atom effect such as iridium or platinum (for example, non-patented) Reference 1). The maximum internal quantum efficiency can theoretically reach 100% by utilizing light emission from the triplet excited state in addition to the singlet excited state, and phosphorescent materials are attracting attention as light emitting materials.

For example, as a green material, the following formula
Tris (2-phenylpyridinato) iridium (III) [Ir (ppy) ₃ ] shown in FIG.

In addition, the following formula, which is a blue light-emitting material according to Non-Patent Document 2 by Adachi et al.
Bis [2- (4,6-difluorophenyl) pyridyl-N, C2 ′] iridium (III) picolylate (FIrpic) has been attracting attention, and since then, the efficiency of organic EL devices using FIrpic has been increased. Studies and new blue phosphorescent complex exploration studies have been actively conducted.

As a result, S. R. Non-patent document 3 by Forrest et al.
Tris [1- (4- (trifluoromethyl) phenyl) -1H-pyrazolate, N, C2 ′] iridium (III) (Irtfmpppz3) and M. E. Non-Patent Document 4 by Thompson et al.
Bis [2- (4 ′, 6′-difluorophenyl) pyridinato-N, C2 ′] tetrakis (1-pyrazolyl) borate (Fir6) has been developed.

In order for these luminescent materials to emit light efficiently, the hole and electron injection balance must be adjusted, and a hole transport agent or electron transport agent must be selected so that these carriers can be sufficiently recombined in the light emitting layer. Don't be.
In particular, since the blue phosphorescent material has a large energy gap, a hole transport agent and an electron transport agent having a wide gap are required. For these phosphorescent materials, Alq ₃ [tris (8-quinolinolato) aluminum] and BAlq ₂ [bis (2-methyl-8-quinolinolato) aluminum-p-phenylphenolate, which are conventionally used for electron transport materials, are used. However, since it does not have a sufficient energy gap for use in phosphorescent materials, it is necessary to develop a new wide gap electron transport material.
M.M. A. Baldo, S.M. Lamansky, P.M. E. Burrows, M.M. E. Thompson, S.M. R. Forrest APPLYED PHYSICS LETTER 1999 75 (1) 4-7 Appl. Phys. Lett. 79, 2082 (2001) J. et al. Appl. Phys. 90 5048 (2001) 4 Polyhedron 23 (2004) 419-428

  The first object of the present invention is to provide a novel triarylboron derivative. The second object of the present invention is to provide a novel organic electroluminescence device using the same.

The first of the present invention is the following general formula (1)
The following general formula (2)
The following general formula (3)
The following general formula (4)
The following general formula (5)
And the following general formula (6)
[R ^{1 to} R ¹⁴ in the formulas in the general formulas (1) to (6) are hydrogen, a linear or branched alkyl group having 1 to 20 carbon atoms, or a linear or branched alkoxy group having 1 to 20 carbon atoms. Group, an alkylamino group having a linear or branched alkyl group having 1 to 20 carbon atoms, an aryl group that may have a linear or branched alkyl group having 1 to 20 carbon atoms as a substituent, or 1 to 20 carbon atoms Independently from the group consisting of an aryloxy group which may have a linear or branched alkyl group as a substituent and an arylamino group which may have a linear or branched alkyl group of 1 to 20 carbon atoms as a substituent. Ar is an arylene group which may have a single bond or a linear or branched alkyl group having 1 to 20 carbon atoms as a substituent, Ar ′ is nitrogen, sulfur or oxygen. (As a substituent, it may also have a linear or branched alkyl group having 1 to 20 carbon atoms) a heteroaryl group having a hetero element selected from the group consisting of a. ]
And a triarylboron derivative selected from the group consisting of:
The second aspect of the present invention relates to the triarylboron derivative according to claim 1, which has a wide energy gap (Eg) of 3.4 eV or more.
The compounds represented by the general formulas (1) to (6) used in the organic electroluminescence device of the present invention preferably have a band gap of 3.4 eV or more. When the band gap shows the above value, the electron transport property can be maintained, the hole blocking effect can be expected, and the light emission efficiency can be improved. In particular, a large band gap is required for emitting a blue phosphorescent material.
The band gap represents the difference between the ionization potential (Ip) and the electron affinity (Ea) of the compound. The ionization potential (Ip) and electron affinity (Ea) of a compound are generally determined based on the vacuum level. The ionization potential (Ip) is the energy required to release electrons at the HOMO (highest occupied molecular orbital) level of a compound to the vacuum level, while the electron affinity (Ea) is at the vacuum level. This is the energy at which electrons fall to the LUMO (lowest molecular orbital) level of a material and stabilize.
The difference between the ionization potential (Ip) and the electron affinity (Ea) can be obtained from the absorption edge of the absorption spectrum of the compound as an energy gap (Eg).
Generally, it can obtain | require with the following formula | equation. If the wavelength of the absorption edge is Wnm, then the energy gap Eg is
Eg = 1240 ÷ W
Can be obtained.
3rd of this invention is related with the triaryl boron derivative of Claim 1 or 2 which shows the light emission edge of a low-temperature phosphorescence spectrum in a wavelength shorter than 500 nm.
The compounds represented by the general formulas (1) to (6) used in the organic electroluminescence device of the present invention preferably have a low-temperature phosphorescence emission edge having a value of 500 nm or less. The measurement of the low-temperature phosphorescence spectrum is generally difficult for a phosphorescent material to be measured at room temperature, and the measurement is performed in a state where an object to be measured is cooled with liquid helium or the like. By measuring this, it is possible to judge whether or not energy transfer to the phosphorescent material to be combined occurs smoothly. In particular, in the case of a combination with a blue phosphorescent material, smooth energy transfer cannot occur unless the value of the emission edge is 500 nm or less.
A fourth aspect of the present invention relates to the triarylboron derivative according to any one of claims 1 to 3, wherein Ar 'in the general formulas (1) to (6) is a pyridyl group.
5th of this invention is related with the triaryl boron derivative in any one of Claims 1-4 whose Ar in General formula (1)-(6) is a single bond or a phenylene group.
According to a sixth aspect of the present invention, Ar in the general formulas (1), (2), (4), (5) and (6) is bonded to the 3'-position and / or the 5'-position. It relates to the triarylboron derivative according to any one of 1 to 5.
7th of this invention is related with the organic electroluminescent element characterized by containing the triaryl boron derivative in any one of Claims 1-6.
An eighth aspect of the present invention relates to an organic electroluminescence device using the triarylboron derivative according to any one of claims 1 to 6 as an electron transport material.
A ninth aspect of the present invention relates to an organic electroluminescence device comprising the triarylboron derivative according to claim 2 and a phosphorescent material in combination.
A tenth aspect of the present invention relates to an organic electroluminescent device characterized by using the triarylboron derivative according to claim 3 and a phosphorescent material together.

The triarylboron derivatives represented by the general formulas (1) to (6) of the present invention are represented by the following general formulas (7) to (12).
[In the general formulas (7) to (12), R ^{1 to} R ¹⁴ are the same as described above, and X is a halogen, preferably Br or Cl, particularly preferably Br.]
In the presence of a base, a catalyst and a solvent, a halogenated triarylboron compound represented by the following general formula (13)
It can be produced by reacting tri (heteroarylmesityl) borane represented by the formula (wherein Ar and Ar ′ are the same as described above).

As a solvent used in these reactions, toluene, a toluene-alcohol mixed solvent, dimethoxyethane, or the like can be used. Regarding the base used in this reaction, inorganic alkali metal salts such as sodium carbonate, potassium carbonate, cesium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, potassium phosphate, lithium hydroxide, sodium hydroxide, potassium hydroxide, Organic bases such as triethylamine, organic alkali metal salts such as sodium methoxide, sodium ethoxide, sodium t-butoxide, potassium t-butoxide, organic base compounds such as tetrabutylammonium hydroxide 1M methanol solution, etc. Can be used. The palladium catalyst used in the catalyst is preferably tetrakis (triphenylphosphino) palladium, but palladium acetate, bis (triphenylphosphine) palladium dichloride, bis (1,1′-bis (diphenylphosphino) ferrocene). Zero-valent organic palladium complexes such as palladium dichloride and bis (1,4-bis (diphenylphosphino) butane) palladium dichloride can be used.
For the aryl boric acid compounds used in these reactions, the corresponding aryl halogen compounds are lithiated with n-butyllithium in an ether solvent such as anhydrous diethyl ether or tetrahydrofuran, and trimethoxyborane or triethoxyboron is added thereto. , Triisopropylboron, pinacolboron, bis (pinacolato) diboron and the like can be easily synthesized.

These reactions are as shown in the following reaction formula.

Examples of the alkyl group for R ^{1 to} R ¹⁴ include methyl, ethyl, propyl, n-butyl, sec-butyl, t-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, Examples include pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl and the like.

  Examples of the substituted or unsubstituted alkoxy group include methoxy group, ethoxy group, 2-methoxyethoxy group, 2- (2-methoxyethoxy) ethoxy group, 2-ethoxyethoxy group, 2-butoxyethoxy group, and 2- (dimethylamino). ) Ethoxy group, 2- (dibutylamino) ethoxy group, propoxy group, isopropoxy group, 3-methoxypropoxy group, 3-ethoxypropoxy group, 3- (dimethylamino) propoxy group, butoxy group, isobutoxy group, sec-butoxy Group, tert-butoxy group, pentoxy group, isopentoxy group, 2-pentoxy group, 3-pentoxy group, neopentoxy group, hexyloxy group, 2-hexyloxy group, 2-ethylhexyloxy group, 2-butylhexyloxy group, heptyloxy group , Octoxy group, 2-octoxy group, nonyloxy Group, decyloxy group, dodecyloxy group, allyloxy group, benzyloxy group, 4-methoxybenzyloxy group, 4-fluorobenzyloxy group, 3- (dimethylamino) benzyloxy group, 4-phenylbenzyloxy group, 1-naphthylmethoxy group, 2-naphthylmethoxy group, 1- (2-methoxynaphthyl) methoxy group, 9-anthrylmethoxy group, diphenylmethoxy group, di (p-tolyl) methoxy group, di (4-methoxyphenyl) methoxy group, di (1 -Naphthyl) methoxy group, triphenylmethoxy group, 3-phenylpropyloxy group and the like.

  Examples of the substituted or unsubstituted alkylamino group include methylamino group, ethylamino group, propylamino group, isopropylamino group, butylamino group, isobutylamino group, pentylamino group, hexylamino group, cyclopentylamino group, and cyclohexylamino group. Octylamino group, heptylamino group, decylamino group, dodecylamino group, dimethylamino group, ethylmethylamino group, diethylamino group, methylpropylamino group, isopropylmethylamino group, butylmethylamino group, isobutylmethylamino group, ethylpropyl Amino group, dipropylamino group, diisopropylamino group, butylethylamino group, ethylisobutylamino group, dibutylamino group, diisobutylamino group, methylpentylamino group, ethylpentylamino , Hexylmethylamino group, ethylhexylamino group, butylhexylamino group, hexylpentylamino group, dihexylamino group, dicyclopentylamino group, cyclohexylmethylamino group, cyclohexylethylamino group, cyclohexylisopropylamino group, dicyclohexylamino group, methyloctyl Amino group, heptylmethylamino group, heptylisopropylamino group, diheptylamino group, methyloctylamino group, octylpropylamino group, dioctylamino group, decylethylamino group, decylisopropylamino group, di (2-ethylhexyl) amino group , Dodecylmethylamino group, dodecylhexylamino group, cyclohexyldodecylamino group, didodecylamino group and the like.

  Examples of the substituted or unsubstituted aryl group include phenyl group, 1-naphthyl group, 2-naphthyl group, 4-phenyl-1-naphthyl group, 4-phenyl-2-naphthyl group, 1-phenyl-5-naphthyl group, 1-anthryl group, 2-anthryl group, 9-anthryl group, 10-phenyl-9-anthryl group, 1-phenanthryl group, 2-phenanthryl group, 3-phenanthryl group, 4-phenanthryl group, 9-phenanthryl group, 1 -Pyrenyl group, 2-pyrenyl group, 2-perylenyl group, 3-perylenyl group, 1-fluoranthenyl group, 2-fluoranthenyl group, 3-fluoranthenyl group, 8-fluoranthenyl group, 2-triphenylenyl Group, 9,9-dimethylfluoren-2-yl group, 9,9-dibutylfluoren-2-yl group, 9,9-dihexylfluore 2-yl group, 9,9-dioctylfluoren-2-yl group, 9,9-diphenylfluoren-2-yl group, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group, p-terphenyl- 3-yl group, p-terphenyl-4-yl group, m-terphenyl-3-yl group, m-terphenyl-4-yl group, o-terphenyl-3-yl group, o-terphenyl- 4-yl group, 4- (1-naphthyl) -1-naphthyl group, o-tolyl group, m-tolyl group, p-tolyl group, p-tert-butylphenyl group, 4-methoxyphenyl group, 4-fluoro Phenyl group, 4-dimethylaminophenyl group, 4-cyanophenyl group, 4- (trifluoromethyl) phenyl group, 4-methyl-1-naphthyl group, 2-methoxy-1-naphthyl group, 10-methyl-9- Enthryl group, 10-methoxy-9-anthryl group, 4-phenyl-8-fluoranthenyl group, 7-dimethylamino-9,9-dimethylfluoren-2-yl group, 3 ', 5'-diphenylbiphenyl-4 -Yl group etc. are mentioned

  Examples of the aryloxy group that may have a linear or branched alkyl group having 1 to 20 carbon atoms as a substituent include those in which oxygen is introduced into the bond part of the various aryl groups exemplified above. For example, the substituted or unsubstituted aryloxy group includes phenoxy group, 1-naphthoxy group, 2-naphthoxy group, 4-phenyl-1-naphthoxy group, 4-phenyl-2-naphthoxy group, 1-phenyl-5-naphthoxy group. Group, 1-anthryloxy group, 2-anthryloxy group, 9-anthryloxy group, 10-phenyl-9-anthryloxy group, 1-phenanthryloxy group, 2-phenanthryloxy group, 3-phenanthryloxy group, 4-phena Nutryloxy group, 9-phenanthryloxy group, 1-pyrenyloxy group, 2-pyrenyloxy group, 1-peryleneoxy group, 2-peryleneoxy group, 3-peryleneoxy group, 1-fluoranthenoxy group, 2-fluoranthenoxy group Group, 3-fluoranthenoxy group, 8-fluoranthenoxy group, 2-triphenylenoxy group, 9, -Dimethylfluorene-2-yloxy group, 9,9-dibutylfluorene-2-iroxy group, 9,9-dihexylfluorene-2-iroxy group, 9,9-dioctylfluorene-2-iroxy group, 9,9-diphenyl Fluorene-2-iroxy group, 2-biphenyliroxy group, 3-biphenyliroxy group, 4-biphenyliroxy group, p-terphenyl-3-iroxy group, p-terphenyl-4-iroxy group, m- Terphenyl-3-Iroxy group, m-Terphenyl-4-Iroxy group, o-Terphenyl-3-Iroxy group, o-Terphenyl-4-Iroxy group, 4- (1-Naphtyl) -1-naphthoxy group , O-triloxy group, m-triloxy group, p-triloxy group, p-tert-butylphenoxy group, 4-methoxyphenoxy group, 4-full Lophenoxy group, 4-dimethylaminophenoxy group, 4-cyanophenoxy group, 4- (trifluoromethyl) phenoxy group, 4-methyl-1-naphthoxy group, 4-phenyl-1-naphthoxy group, 2-methoxy-naphthoxy group Group, 10-methyl-9-anthryloxy group, 10-methoxy-9-anthryloxy group, 4-phenyl-fluoranthene-8-iroxy group, 7-dimethylamino-9,9-dimethylfluoranthene-2-yloxy group, 3 ', 5'-diphenylbiphenyl-4-iroxy group and the like can be mentioned.

  Examples of the substituted or unsubstituted arylamino group are groups in which an amino group is substituted for the monovalent group mentioned as the aryl group, and examples thereof include a 1-phenylamino group, an N-o-tolylamino group, an N- m-tolylamino group, Np-tolylamino group, N-1-naphthylamino group, N-2-naphthylamino group, N- (4-methoxyphenyl) amino group, N- (4-ethylphenyl) amino group, N- (4-fluorophenyl) amino group, N- (4-dimethylaminophenyl) -amino group, 2-naphthylamino group, N- (1-anthryl) amino group, N- (2-anthryl) amino group, N- (9-anthryl) amino group, N- (10-methyl-9-anthryl) amino group, N- (9-phenanthryl) amino group, N- (9,9-dimethylfluorene-2- L) amino group, N- (3-fluoranthenyl) amino group, N- (1-pyrenyl) amino group, N- (1-pyrenyl) amino group, N- (3-perylenyl) amino group, diphenylamino group N, N-di (o-tolyl) amino group, N, N-di (m-tolyl) amino group, N, N-di (p-tolyl) amino group, N, N-di (1-naphthyl) Amino group, N, N-di (2-naphthyl) amino group, N- (1-naphthyl) -N-phenylamino group, N- (4-methoxyphenyl) -N-phenylamino group, N- (4- Ethylphenyl) -N-phenylamino group, N- (4-fluorophenyl) -N-phenylamino group, N- (4-dimethylaminophenyl) -N-phenylamino group, N- (2-naphthyl) -N -Phenylamino group, N- (1-naphthyl) -N- o-tolyl) amino group, N- (2-naphthyl) -N- (o-tolyl) amino group, N- (1-anthryl) phenylamino group, N- (2-anthryl) -N-phenylamino group, N- (9-anthryl) -N-phenylamino group, N- (10-methyl-9-anthryl) -N-phenylamino group, N- (1-anthryl) -N- (1-naphthyl) amino group, N- (2-anthryl) -N- (1-naphthyl) amino group, N- (9-anthryl) -N- (2-naphthyl) amino group, N- (10-methyl-9-anthryl) -N- (2-naphthyl) amino group, N- (9-phenanthryl) -N-phenylamino group, N- (9-phenanthryl) -N- (p-tolyl) amino group, N- (1-naphthyl) -N- (9-phenanthryl) amino group, N- (9 , 9-dimethylfluoren-2-yl) -N-phenylamino group, N- (9,9-dimethylfluoren-2-yl) -N- (m-tolyl) amino group, N- (9,9-dimethyl) Fluoren-2-yl) -N- (1-naphthyl) amino group, N- (9,9-dimethylfluoren-2-yl) -N- (4-methoxyphenyl) amino group, N- (1-anthryl) -N- (9,9-dimethylfluoren-2-yl) amino group, N- (9,9-dimethylfluoren-2-yl) -N- (9-phenanthryl) amino group, N, N-bis (9 , 9-dimethylfluoren-2-yl) amino group, N- (3-fluoranthenyl) -N-phenylamino group, N- (3-fluoranthenyl) -N- (p-tolyl) amino group, N -(3-Fluoranthenyl) -N- (4- Toxiphenyl) amino group, N- (3-fluoranthenyl) -N- (1-naphthyl) amino group, N- (3-fluoranthenyl) -N- (2-naphthyl) amino group, N- (1 -Anthryl) -N- (3-fluoranthenyl) amino group, N- (9-anthryl) -N- (3-fluoranthenyl) amino group, N- (3-fluoranthenyl) -N- (9 -Phenanthryl) amino group, N- (3-fluoranthenyl) -N- (9,9-dimethylfluoren-2-yl) amino group, N, N-di (3-fluoranthenyl) amino group, N- Phenyl-N- (1-pyrenyl) amino group, N- (1-pyrenyl) -N- (p-tolyl) amino group, N- (4-dimethylaminophenyl) -N- (1-pyrenyl) amino group, N- (1-naphthyl) -N- (1-pyrenyl Amino group, N- (2-naphthyl) -N- (1-pyrenyl) amino group, N- (1-anthryl) -N- (1-pyrenyl) amino group, N- (9-anthryl) -N- ( 1-pyrenyl) amino group, N- (1-pyrenyl) -N- (9-phenanthryl) amino group, N- (9,9-dimethylfluoren-2-yl) -N- (1-pyrenyl) amino group, N- (3-fluoranthenyl) -N- (1-pyrenyl) amino group, N- (9-fluoranthenyl) -N- (1-pyrenyl) amino group, N- (3-perylenyl) -N- Phenylamino group, N- (3-perylenyl) -N- (m-tolyl) amino group, N- (4-dimethylaminomethyl) -N- (3-perylenyl) amino group, N- (1-naphthyl)- N- (3-perylenyl) amino group, N- (2-naphthyl) -N -(3-perylenyl) amino group, N- (1-anthryl) -N- (3-perylenyl) amino group, N- (3-perylenyl) -N- (9-phenanthryl) amino group, N- (9, 9-dimethylfluoren-2-yl) -N- (3-perylenyl) amino group, N- (9-fluoranthenyl) -N- (3-perylenyl) amino group, bis (4-dimethylaminophenyl) amino group And bis (4-diphenylaminophenyl) amino group.

  Examples of the arylene group in Ar include an arylene group corresponding to those exemplified in the examples of the aryl group, and the heteroaryl group of Ar ′ has 1 to 3 nitrogen atoms in one ring. One having one sulfur in the ring One having one sulfur and nitrogen in one ring One having one nitrogen and oxygen in one ring One oxygen and sulfur The thing etc. which have in one ring can be mentioned.

  Specific examples of Ar′-Ar— are shown below.

The Me is a methyl group.

Examples of the triarylboron derivative of the present invention are shown below. In the formulas in this specification, all lines other than the bond protruding from the ring are abbreviations for —CH ₃ (methyl group).

  The triarylboron derivative of the present invention has high electron transport performance. Therefore, it can be used as an electron injection material and an electron transport material.

  When the triarylboron derivative of the present invention is used in an organic electroluminescence device, it can also be used in combination with a suitable light emitting material (dopant).

  When the triarylboron compound of the present invention is used for an electron transport layer, it can be used as an electron injection material or an electron transport material. It can also be used in combination with other electron transport materials.

  Next, the organic electroluminescence element of the present invention will be described. The organic electroluminescence device of the present invention is a device in which a single layer or a multilayer organic compound is laminated between an anode and a cathode, and at least one layer of the organic compound layer contains the triarylboron derivative of the present invention. When the organic electroluminescence element is a single layer, a light emitting layer is provided between the anode and the cathode. The light emitting layer contains a light emitting material and may contain a hole injecting material or an electron injecting material for the purpose of transporting holes injected from the anode or electrons injected from the cathode to the light emitting material. . Examples of the configuration of the multilayer organic electroluminescence device include, for example, anode / hole transport layer / light emitting layer / electron transport layer / cathode, anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / cathode. , Anode / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode, anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode, etc. Laminated ones are examples. 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 layer 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 element of the present invention will be described in detail by taking as an example an element structure comprising an anode / hole transport layer / light emitting layer / 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 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 on the substrate 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 small work function (4 eV or less), an alloy of metals having a small 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 electroluminescence 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. When a hole transport compound is disposed between two electrodes to which an electric field is applied and holes are injected from the anode, a hole transport material having a hole mobility of at least 10 ⁻⁶ cm ² / V · second or more is obtained. preferable. The hole transport material used for the hole transport layer used in the organic electroluminescence device of the present invention is not particularly limited as long as it has the above-mentioned preferable properties. It is possible to select and use any of the materials conventionally used as hole charge injection / transport materials in photoconductive materials and known materials used for the hole transport layer of organic electroluminescent devices. it can.

  Examples of the hole transfer 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′-diaminobiphenyl (TPD), N, N′-di (1-naphthyl) -N, N′-diphenyl-4,4′-diaminobiphenyl (α-NPD), etc. And triarylamine 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. It may be a thing.

  The light emitting material of the light emitting layer of the organic electroluminescence device of the present invention is not particularly limited, and any one of conventionally known compounds can be selected and used.

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 (tris). Fluorescent materials such as (8-hydroxyquinolinolato) aluminum (Alq ₃ ), tris (4-methyl-8-hydroxyquinolinolato) aluminum (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) (Irtfmpppz3), bis [2- (4 ', 6'-difluorophenyl) pyridinato-N, C2' And phosphorescent materials such as tetrakis (1-pyrazolyl) borate (Fir6), tris (2-phenylpyridinato) iridium (III) [Ir (ppy) ₃ ], and the like.

  The light-emitting layer can also be 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 the host material used at this time is 4,4'-di (N-carbazolyl) -1,1'-biphenyl (CBP). 1,2-di (N-carbazolyl) benzene, 2,2′-di (4 ″-(N-carbazolyl) phenyl) -1,1′-biphenyl (4CzPBP) and the like.

  The guest material is preferably 0.01 to 40% by weight, more preferably 0.1 to 20% by weight, based on the host material.

  As a material for the electron transport layer of the organic electroluminescence device of the present invention, the triarylboron derivative of the present invention is preferable. Although this thing can be used independently, you may use together with another electron transport material.

  The organic electroluminescent device of the present invention may further include an electron injection layer composed of an insulator between the cathode and the organic layer for the purpose of further improving the electron injection property. As the insulator used here, it is preferable to use at least one metal compound selected from alkali metal halides and alkaline earth metal halides. Examples of the alkali metal halide include lithium fluoride, sodium fluoride, potassium fluoride, cesium fluoride, and lithium chloride. Examples of the alkaline earth halide include magnesium fluoride, calcium fluoride, barium fluoride, and strontium fluoride.

  The method for forming the hole transport layer and the light emitting layer is not particularly limited. For example, a dry film forming method (for example, vacuum vapor deposition method, ionization vapor deposition method) or a wet film forming method (solution coating method (for example, spin coating method, cast method, ink jet method)) can be used. As a method for forming the electron transport layer of the triarylboron compound of the present invention, a dry film forming method (for example, a vacuum evaporation method or an ionization evaporation method) is preferable. In addition, the above-described film formation method may be used in combination for manufacturing the element.

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, at a boat temperature (deposition source temperature) of about 50 to 500 ° C. under a vacuum of about 10 ⁻⁵ Torr or less, at a substrate temperature of about −50 to 300 ° C., 0.01 to 50 nm / sec. Vapor deposition is preferred. When forming each layer of a positive hole transport layer, a light emitting layer, and an electron carrying layer using a some compound, it is preferable to co-evaporate each boat which put the compound, temperature-controlling each.

  When forming the hole transport layer and the light emitting 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 and the like), aprotic solvents (for example, N, N'-dimethylacetamide, dimethyl sulfoxide and the like), 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, or the like, or by encapsulating the device in an inert substance. Examples of the inert substance include paraffin, silicon oil, and fluorocarbon. Examples of the material used for the protective layer include fluorine resin, 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 observed when a voltage of about 1.5 to 20 V is applied with the positive polarity of the anode and the negative polarity of the cathode. Moreover, the organic electroluminescent element of this invention can be used also as an element of an alternating current drive. 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 electroluminescent device 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 devices, various display devices, various signs. It can be used for various sensors and various accessories.

  47-60 show preferred examples of the organic electroluminescence device of the present invention.

  FIG. 47 is a cross-sectional view showing an example of the organic electroluminescence element of the present invention. FIG. 47 shows a structure in which an anode 2, a light emitting layer 3 and a cathode 4 are sequentially provided on a substrate 1. The light-emitting element used here is useful when it has a single function of hole transport, electron transport, and light emission, or when a compound having each function is used in combination. is there.

  FIG. 48 is a cross-sectional view showing another example of the organic electroluminescence element of the present invention. FIG. 48 shows a structure in which an anode 2, a hole transport layer 5, a light emitting layer 3, and a cathode 4 are sequentially provided on a substrate 1. In this case, the light emitting layer is useful when it has an electron transporting function.

  FIG. 49 is a cross-sectional view showing another example of the organic electroluminescence element of the present invention. FIG. 49 shows a structure in which an anode 2, 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 light emitting layer is useful when it has a hole transporting function.

  FIG. 50 is a cross-sectional view showing another example of the organic electroluminescence element of the present invention. FIG. 50 shows a structure 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 separates 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. 51 is a cross-sectional view showing another example of the organic electroluminescence element of the present invention. FIG. 51 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 driving the light emitting element at a low voltage.

  FIG. 52 is a cross-sectional view showing another example of the organic electroluminescence element of the present invention. FIG. 52 shows a structure 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 low voltage driving of the light emitting element.

  FIG. 53 is a cross-sectional view showing another example of the organic electroluminescence element of the present invention. FIG. 53 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, an electron injection layer 8 and a cathode 4 are sequentially provided on a substrate 1. In this case, hole injection from the anode 2 is improved and electron injection from the cathode 4 is improved, which is the most effective for low voltage driving.

  54-60 is sectional drawing which shows the other example in the organic electroluminescent element of this invention. 54 to 60 show a configuration in which a hole blocking layer 9 is inserted between the light emitting layer 3 and the cathode 4 or the electron transporting layer 6. This has the 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 side, and is effective in improving the light emission efficiency of the organic electroluminescence element.

  54 to 60, 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 has a single layer structure or a multilayer structure. There may be.

  47 to 60 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.

The triarylboron derivative of the present invention not only exhibits higher electron transport performance than a typical electron transport material Alq ₃ known so far, but also has a high hole blocking property, so that it is used for a blue phosphorescent light emitting device. Thus, it is possible to emit light with higher efficiency than the conventional organic electroluminescence element. Therefore, the triarylboron derivative of the present invention is extremely important industrially.

Triarylboron derivatives of the present invention is found to exhibit high electron transporting performance much than typical electron transporting material Alq ₃ known heretofore as shown in the Examples. Therefore, it has become possible to provide materials suitable for organic semiconductor devices such as organic electroluminescence elements and organic semiconductor transistors. In addition, by using the triarylboron derivative of the present invention, it is possible to provide a long-life organic electroluminescence device that operates at a driving voltage lower than that of a conventional organic electroluminescence device and has excellent light emission characteristics and excellent stability. It became possible. Therefore, the triarylboron derivative of the present invention is extremely important industrially.
In addition, since the triarylboron derivative does not have fluorescence in the visible region, the triarylboron derivative does not exhibit a light emitting function like that of Alq ₃ . Therefore, when it is used as an electron transport layer, it does not say that light is emitted when the driving voltage of the organic electroluminescence element is increased as in Alq ₃ . For this reason, the selection of the light emitting material is easy.

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

Example 1
(1) Synthesis of tri (4-bromomesityl) borane (TBrMB)
2,4-Dibromomesitylene (20.0 g 71.9 mmol) was placed in a 500 ml four-necked flask and nitrogen flowed for 40 minutes. This was charged with 300 ml of dry diethyl ether and cooled to -75 ° C. To this solution, a hexane solution of n-butyllithium (1.58M 51 ml 79.1 mmol) was added dropwise over 20 minutes, and after completion of the addition, the temperature was raised to room temperature and stirred at 10 ° C. or higher for 2 hours. The reaction solution was cooled again to −75 ° C., and boron trifluoride diethyl ether complex (3.16 g 22.3 mmol) was added dropwise over 3 minutes. After completion of the addition, the mixture was returned to room temperature and stirred for 12 hours. This reaction solution was extracted with 500 ml of toluene, washed twice with 400 ml of 5% brine, dried over magnesium sulfate, and filtered to remove magnesium sulfate. The filtrate was concentrated to obtain a pale yellow viscous body. The viscous body was purified with a silica gel column (developing liquid hexane) to obtain 7.4 g of white crystals of tri (4-bromomesityl) borane (TBrMB). ^The structure was confirmed by ¹ H-NMR. (Yield 54.6% Theoretical yield 13.5g)

(2) Synthesis of tri [4- (3-pyridyl) -mesityl] borane (TPYMB)
Tri (4-bromomesityl) borane (TBrMB) (2.0 g 3.3 mmol), 3- (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl in a 300 ml four-necked flask ) A 60 ml aqueous solution of pyridine (2.4 g 11.6 mmol), toluene 100 ml, ethanol 60 ml, sodium carbonate (2.8 g 26.4 mmol) was added, and nitrogen flowed for 40 minutes. The solution was heated to 70 ° C., tetrakistriphenylphosphine palladium (230 mg 0.198 mmol) was added and allowed to react for 24 hours. After cooling to 40 ° C., the reaction solution was separated and washed twice with 5% brine, dried over magnesium sulfate, and filtered to remove magnesium sulfate. The filtrate was concentrated to obtain a pale yellow viscous body. This viscous body was purified by a silica gel column (developing solution ethyl acetate → chloroform / methanol = 30/1) to obtain 1.5 g of white crystals of tri [4- (3-pyridyl) -mesityl] borane (TPYMB). ^The structure was confirmed by ¹ H-NMR. ¹ H-NMR is shown in FIG. (Yield: 76.3% Theoretical yield: 1.98 g) The thermal properties and electrochemical properties of this product are shown in Table 1 and FIGS.

Example 2
(1) Synthesis of 3- (1-chlorophenyl) -pyridine (ClPHPY)
A 500 ml four-necked flask was charged with a 150 ml aqueous solution of 4-chlorophenylboronic acid (10 g 65.6 mmol), 3-bromopyridine (10.4 g 65.6 mmol), toluene 200 ml, ethanol 100 ml, sodium carbonate (27.1 g). While stirring, nitrogen flow was performed for 1 hour. This liquid was heated to 70 ° C., tetrakistriphenylphosphine palladium (1.5 g, 1.31 mmol) was added, and the reaction was performed for 4 hours. The reaction solution was cooled to 30 ° C., separated and washed twice with 5% brine, dried over magnesium sulfate, filtered, and concentrated to obtain a light orange viscous body. This viscous body was purified with a silica gel column (developing solution: ethyl acetate / hexane = 1/1) to obtain 11.3 g of 3- (1-chlorophenyl) -pyridine (ClPHPY) as a pale yellow viscous body. ^The structure was confirmed by ¹ H-NMR. (Yield 90.9% Theoretical yield 12.4g)

(2) Synthesis of 1- (3-pyridyl) -4- (4,4,5,5, -tetramethyl-1,3,2-dioxaborolan-2-yl) -benzene (PHPYDOB)
In a 500 ml four-necked flask, 3- (1-chlorophenyl) -pyridine (ClPHPY) (6.8 g 3.6 mmol), bispinacol diboron (10 g 3.9 mmol), bis (dibenzylideneacetone) palladium (617 mg 0.107 mmol) ), Tricyclohexylphosphine (903 mg 0.32 mmol), potassium acetate (5.27 g 5.37 mmol)
250 ml of dry dioxane was added, and nitrogen flow was performed for 40 minutes with stirring. This solution was heated to 80 ° C. and reacted for 24 hours. After completion of the reaction, the reaction mixture was cooled to 30 ° C., and 300 ml of chloroform was added thereto, followed by separation and washing three times with 5% saline. The solution was dried over magnesium sulfate, filtered and concentrated to obtain a brown viscous body. This viscous body was purified with a silica gel column (developing solution ethyl acetate / chloroform = 1/1) to give 1- (3-pyridyl) -4- (4,4,5,5, -tetramethyl-1,3,2-dioxaborolane. 6.7 g of light yellow viscous body of 2-yl) -benzene (PHPYDOB) was obtained. ^The structure was confirmed by ¹ H-NMR. (Yield 67.3% Theoretical yield 10.1 g)

(3) Synthesis of tri [4- (4-phenyl-3-pyridyl) -mesityl] borane (TPPYMB)
In a 300 ml four-necked flask, tri (4-bromomesityl) borane (TBrMB) (2 g 3.31 mmol), 1- (3-pyridyl) -4- (4,4,5,5, -tetramethyl-1,3, 2-Dioxaborolan-2-yl) -benzene (PHPYDOB) (3.6 g 11.9 mmol), toluene 150 ml, ethanol 70 ml, and sodium carbonate 3.5 g in 70 ml aqueous solution were added and nitrogen flowed for 40 minutes with stirring. This solution was heated to 70 ° C., tetrakistriphenylphosphine palladium (230 mg 0.20 mmol) was added and reacted for 24 hours. After completion of the reaction, the reaction mixture was cooled to 30 ° C. and separated and washed three times with 5% saline. This solution was dried over magnesium sulfate, filtered and concentrated to obtain a pale yellow viscous body. This viscous body was purified with a silica gel column (developing solution ethyl acetate → chloroform / methanol = 30/1) to obtain 2.12 g of tri [4- (4-phenyl-3-pyridyl) -mesityl] borane (TPPYMB) as white crystals. Obtained. The structure was confirmed by ¹ H-NMR shown in FIG. (Yield: 77.4% Theoretical yield: 2.74 g) The thermal properties and electrochemical properties of this product are shown in Table 1 and FIGS.

Td: decomposition temperature, Tg: secondary transition temperature, Tc: crystallization temperature, Tm: melting point, Ip: ionization potential, Eg: energy gap, Ea: electroaffinity (electron affinity), n. d. : Not detected.
As for Tg (secondary transition temperature), a sample is added to DSC (Differential Scanning Calorimeter), the melted sample is rapidly cooled, and a curve representing the glass transition appears on the chart when repeated 2-3 times. The curves are connected by tangent lines, and the temperature at the intersection is adopted as Tg.
Tc (crystallization temperature) is a temperature at which a crystal once melted is crystallized again. Those with Tg generally do not have Tc.
As for Tm (melting point), an endothermic curve appears when a sample is added to the DSC and the temperature is raised, so the temperature at the maximum is read and the temperature is defined as Tm.
As for Td (decomposition temperature), when a sample is added to DTA (Differential Thermal Analyzer) and heated, the sample is decomposed by heat and the weight starts to decrease. The temperature at which the decrease starts is read and the temperature is defined as Td.
Regarding the energy gap (Eg), an absorption curve of the thin film prepared with a vapor deposition machine is measured with an ultraviolet-visible absorptiometer. A tangent line is drawn at the rising edge of the thin film on the short wavelength side, and the wavelength W (nm) at the obtained intersection is substituted into the following equation to obtain the target value. The value obtained thereby becomes Eg.
Eg = 1240 ÷ W
For example, if the value W (nm) obtained by drawing a tangent is 470 nm, the value of Eg at this time is Eg = 1240 ÷ 470 = 2.63 (eV)
It will be said.
Ip (ionization potential) is measured using an ionization potential measuring apparatus (for example, Riken Keiki AC-1), and the value of the voltage (eV) at which the sample to be measured starts ionization is read.
Ea (electron affinity) is a value obtained by subtracting Eg from Ip.
Intensity au in this specification was measured at 4.2K in a cryostat using a streak camera manufactured by Hamamatsu Photonics.

Example 3
(1) Synthesis of 2- (dimesitylboryl) -4,6-dibromomesitylene (MBDBrMES)
Tribromomesitylene (TBrMES) (10.9 g 30.5 mmol) was placed in a 500 ml four-necked flask and nitrogen flowed for 40 minutes. This was charged with 300 ml of dry diethyl ether and cooled to -75 ° C. To this solution, n-butyllithium hexane solution (1.58M 19.3 ml 30.5 mmol) was added dropwise over 15 minutes, and after completion of the addition, the temperature was raised to room temperature and stirred at 10 ° C. or higher for 2 hours. The reaction solution was cooled again to −75 ° C., and a solution of dimesitylborane fluoride [10 g (9 g 33.6 mmol in terms of 90% purity)] in 50 ml of diethyl ether was added dropwise over 20 minutes. Stir for hours. This reaction solution was extracted with 500 ml of toluene, separated and washed twice with 400 ml of 5% brine, dried over magnesium sulfate, and filtered to remove magnesium sulfate. The filtrate was concentrated to obtain a pale yellow viscous body. This viscous body was purified with a silica gel column (developing liquid hexane) to obtain 10.8 g of white crystals of 2- (dimesitylboryl) -4,6-dibromomesitylene (MBDBrMES). ^The structure was confirmed by ¹ H-NMR. (Yield 73.4% Theoretical yield 14.7 g)

(2) 1,4-bis (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) -benzene (BDOBBz)
In a 500 ml four-necked flask, 1,4-dibromobenzene (6.3 g 26.8 mmol), bispinacolatodiboron (15.0 g 59.1 mmol), potassium acetate (15.8 g 161 mmol), diphenylphosphinoferrocene palladium dichloride (1.3 g 1.61 mmol) was added and nitrogen flowed for 30 minutes. To this, 250 ml of dry dimethylformamide was added and stirred at 85 ° C. for 12 hours. After cooling to 40 ° C., the mixture was extracted with chloroform, separated and washed twice with 5% brine, dried over magnesium sulfate, and filtered to remove magnesium sulfate. The filtrate was concentrated to give a brown solid. This solid was purified with a silica gel column (developing solution chloroform / hexane) and 1,4-bis (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) -benzene (BDOBBz). Of white crystals was obtained. ^The structure was confirmed by ¹ H-NMR. (Yield 81.5% Theoretical yield 8.8 g)

(3) Synthesis of 1- (3-pyridyl) -4- (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) -benzene (PHPYDOB)
In a 500 ml four-necked flask, 1,4-bis (4,4,5,5-tetramethyl-1,3,2-dioxabosan-2-yl) -benzene (BDOBBz) (7.2 g 21.8 mmol), 3 -A 100 ml aqueous solution of bromopyridine (2.7 g 16.8 mmol), toluene 200 ml, ethanol 100 ml, sodium carbonate (10.67 g 100.7 mmol) was added, and nitrogen flow was performed while stirring for 40 minutes. This solution was heated to 70 ° C., tetrakistriphenylphosphene palladium (387 mg 0.336 mmol) was added and allowed to react for 2 hours. After cooling to 40 ° C., the reaction solution was separated and washed twice with 5% brine, dried over magnesium sulfate, and filtered to remove magnesium sulfate. The filtrate was concentrated to obtain a brown viscous body. This viscous body was purified with a silica gel column (developing solution chloroform / ethyl acetate = 3/1) to give 1- (
A pale yellow viscous substance 1.91 g of 3-pyridyl) -4- (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) -benzene (PHPYDOB) was obtained. ^The structure was confirmed by ¹ H-NMR. (Yield 40.5% Theoretical yield 4.7 g)

(4) Synthesis of 2- (dimesitylboryl) -4,6-bis (3-pyridylphenyl) mesitylene (PPYTMB)
To a 300 ml four-necked flask was 2- (dimesitylboryl) -4,6-dibromomesitylene (MBDBrMES) (1.38 g 2.62 mmol), 1- (3-pyridyl) -4- (4,4,5,5-tetra Methyl-1,3,2-dioxaborolan-2-yl) -benzene (PHPYDOB) (1.84 g 6.54 mmol) 100 ml toluene, 60 ml ethanol, 60 ml aqueous solution of sodium carbonate (2.2 g 21.0 mmol), The solution that was nitrogen-flowed for 40 minutes was heated to 70 ° C., tetrakistriphenylphosphine palladium (121 mg 0.105 mmol) was added, and the mixture was allowed to react for 24 hours. After cooling to 40 ° C., the reaction solution was separated and washed twice with 5% brine, dried over magnesium sulfate, and filtered to remove magnesium sulfate. The filtrate was concentrated to obtain a yellow viscous body. The viscous body was purified with a silica gel column (developing solution chloroform / ethyl acetate = 1 / 1.5) to obtain 763 mg of white crystals of 2- (dimesitylboryl) -4,6-bis (3-pyridylphenyl) mesitylene (PPYTMB). It was. ^The structure was confirmed by ¹ H-NMR. (Yield 40.5% Theoretical yield 1.77 g)

Example 4, Comparative Example 1
Organic EL device using Alq [(8-quinolylato) aluminum] (Comparative Example 1) and organic EL device using tri [4- (3-pyridyl) -mesityl] borane (TPYMB) of Example 1 (implementation) Comparison of Example 4) (1) Device Configuration Comparative Example 1: ITO / NPD (50 nm) / Alq (70 nm) / LiF (0.5 nm) / Al (100 nm)
Example 4: ITO / NPD (50 nm) / Alq (40 nm) / TPYMB (30 nm) / LiF (0.5 nm) / Al (100 nm)
(2) The voltage-current density characteristics of both elements are shown in FIG. 6, the voltage-luminance characteristics are shown in FIG. 7, the voltage-luminous efficiency is shown in FIG. 8, the voltage-current efficiency characteristics are shown in FIG. Is shown in Table 3.

Turn on voltage: Applied voltage Current density: Current density E. : Luminous efficiency C.I. E. : Current efficiency

Example 5
A blue phosphorescent device (Example 4) using tri [4- (3-pyridyl) -mesityl] borane (TPYMB) of Example 1 and 3- (4-biphenylyl) -4-phenyl instead of TPYMB Comparison with blue phosphorescent device (Comparative Example 2) using -5- (4-t-butylphenyl) -1,2,4-triazole (TAZ) (1) Device configuration Comparative Example 2: ITO / TPDPES: TBPAH (10 wt%: 20 nm) / DTASI (20 nm) / 4CZPBP: FIrpic (9 wt%: 30 nm) / TAZ (30 nm) / LiF (0.5 nm) / Al (100 nm)
Example 5: ITO / TPDPES: TBPAH (10 wt%: 20 nm) / DTASI (20 nm) / 4CZPBP: FIrpic (9 wt%: 30 nm) / TPYMB (30 nm) / LiF (0.5 nm) / Al (100 nm)
(2) The voltage-current density characteristics of both elements are shown in FIG. 10, the voltage-luminance characteristics are shown in FIG. 11, the voltage-luminous efficiency characteristics are shown in FIG. 12, the voltage-current efficiency characteristics are shown in FIG. 14 and Table 4 shows the element characteristics.

QE: External quantum efficiency

Example 6 (Green phosphorescent device using TPYMB as electron transport material)
(1) Element configuration ITO / TPDPES: TBPAH 10 wt% (20 nm) / m-DTATPB (30 nm) / CBP: Ir (ppy) ₃ 9 wt% / TPYMB / LiF (0.5 nm) / Al (100 nm)
Part 1: Light emitting layer = CBP: Ir (ppy) ₃ 9 wt% (30 nm)
Electron transport layer = TPYMB (30 nm)
Part 2: Light emitting layer = CBP: Ir (ppy) ₃ 9 wt% (20 nm)
Electron transport layer = TPYMB (40 nm)
Part 3: Light emitting layer = CBP: Ir (ppy) ₃ 9 wt% (10 nm)
Electron transport layer = TPYMB (50 nm)
TPDPES is a poly [oxy-1,4-phenylenesulfonyl-1,4-phenyleneoxy-1,4-phenylene (phenylimino) (1,1'-biphenyl) -4,4'-diyl (phenylimino)- 1,4-phenylene] {poly [oxy-1,4-phenylsulfonyl-1,4-phenylene-1,4-phenylene) (phenylimino) (1,1′-biphenyl) -4,4′-diyl (phenylimino) -1,4-phenylene]} (9CI) (CA INDEX NAME).
TBPAH is tris (4-bromophenyl) aminium hexachloroantimonate [Tris (4-bromophenyl) aminium hexachloroantimonate].
(2) Evaluation of device FIGS. 16 to 19 show voltage-current density, voltage-luminance, voltage-luminous efficiency, voltage-current efficiency characteristics, and FIG. 20 shows luminance-current efficiency characteristics. FIG. 21 shows the EL spectrum. Table 5 summarizes the obtained device characteristics. It was found from the EL spectrum that emission of only Ir (ppy) ₃ was observed from any of the elements. As the thickness of the light emitting layer is reduced and TPYMB is increased, the current injection property tends to be improved in view of the current characteristics of FIG. In the device having the light emitting layer 10 nm (100 mm), the luminous efficiency and the current efficiency are dramatically improved as compared with the element having the light emitting layer 30 nm (300 mm), and the luminous efficiency is 87.7 lumen / W at 100 cd / m ² . A very efficient result with an external quantum efficiency of 24.3% was obtained. This is probably because the electron mobility of TPYMB is higher than that of the light-emitting layer, so that the current injection property is improved when the light-emitting layer is thinned, and as a result, it is driven at a low voltage, thereby increasing the efficiency.

Examples 7 to 9 (Examination of hole transport layer in green phosphor element using TPYMB as electron transport layer)
Aiming for further low voltage driving, the hole transport layer of the light emitting layer 10 nm / electron transport layer TPYMB 50 nm type element, which is the most efficient, is considered to have excellent TAPC and hole injection properties, which are said to have relatively high hole mobility. Each of the devices using DTNTPH as a hole transport layer was prepared and evaluated.
(1) Device Configuration Example 7: ITO / TPDPES: TBPAH 10 wt% (20 nm) / m-DTATPB (30 nm) / CBP: Ir (ppy) ₃ 9 wt% (10 nm) / TPYMB (50 nm) / LiF (0.5 nm) / Al (100 nm)
Example 8: ITO / TPDPES: TBPAH 10 wt% (20 nm) / TAPC (30 nm) / CBP: Ir (ppy) ₃ 9 wt% (10 nm) / TPYMB (50 nm) / LiF (0.5 nm) / Al (100 nm)
Example 9: ITO / TPDPES: TBPAH 10 wt% (20 nm) / DTNTPH (30 nm) / CBP: Ir (ppy) ₃ 9 wt% (10 nm) / TPYMB (50 nm) / LiF (0.5 nm) / Al (100 nm)
TPDPES, TBPAH, CBP, and Ir (ppy) ₃ are the same as described above.
(2) Evaluation Voltage-current density characteristic (logarithm), voltage-current density characteristic (linear), voltage-luminance characteristic (logarithm), voltage-luminance characteristic (linear), voltage-luminous efficiency characteristic, voltage of each element -Current efficiency characteristics, EL spectrum at 25 mA / cm ² are shown in FIGS. 22 to 28, and characteristics of each element are shown in Table 6.
Logarithmic and linear plots of voltage-current characteristics in FIGS. 22 and 23, logarithmic and linear plots of voltage-luminance characteristics in FIGS. 24 and 25, voltage-luminous efficiency characteristics and voltage-current efficiency characteristics in FIGS. Summarized in From the EL spectrum, light emission of only Ir (ppy) ₃ is observed from any element. From the voltage-current characteristics shown in FIGS. 22 and 23, it can be seen that the device using TAPC and DTNTPH has improved current injection properties than m-DTATPB as expected. However, from the voltage-luminance characteristics of FIGS. 24 and 25, it can be seen that TAPC has improved brightness but DTNTPH has decreased.
Since the device using TAPC was driven at a lower voltage than the device using m-DTATPB, the efficiency was further improved, and the luminous efficiency at 100 cd / m ^{2 was} 92.7 lumen / W and the external quantum efficiency was 24.2%. Extremely efficient light emission was obtained. This is considered to be due to the fact that the carrier balance is extremely good in addition to the exciton confinement effect of TAPC. On the contrary, in the element using DTNTPH, although the current injection is the best, the efficiency is the lowest.

Example 10 (blue phosphorescent device using TPYMB as an electron transport material), Comparative Example 3
(1) Device Configuration Example 10: ITO / TPDPES: TBPAH 10 wt% (20 nm) / DTASI (30 nm) / 4CZPBP: Flrpic 9 wt% (30 nm) / TPYMB (30 nm) / LiF (0.5 nm) / Al (100 nm)
Comparative Example 3: ITO / TPDPES: TBPAH 10 wt% (20 nm) / DTASI (30 nm) / 4CZPBP: Flrpic 9 wt% (30 nm) / TAZ (30 nm) / LiF (0.5 nm) / Al (100 nm)
TPDPES, TBPAH, DTASI, 4CZPBP, and TAZ are the same as described above.
(2) Evaluation of device FIGS. 29 to 32 show voltage-current density, voltage-luminance, voltage-luminous efficiency, and voltage-current efficiency characteristics. FIG. 33 shows an EL spectrum at 25 mA / cm ² , and FIG. 34 shows an enlarged EL spectrum of a portion of 300 to 450 nm. From the EL spectra of FIGS. 33 and 34, only Flrpic emission is observed from the element using TPYMB, whereas the element using TAZ is considered to be TAZ having a peak near 380 nm other than Flrpic. Luminescence is observed. From this result, it is considered that the hole block property of TPYMB exceeds TAZ. From the voltage-current characteristics of FIG. 29, a current density larger than TAZ is observed in the element using TPYMB. It can also be seen from the luminance characteristics of FIG. This is apparently due to the fact that the electron mobility is higher than TAZ than the exciton confinement effect of TPYMB. As is apparent from Table 7, the efficiency of the device using TPYMB (Example 10) was improved, with a luminous efficiency of 29.1 lumen / W and an external quantum efficiency of 17.5% at 100 cd / m ^2. Light emission is obtained.

Example 11 (Blue phosphor element using TPYMB as electron transport material)
(1) Element configuration ITO / TPDPES: TBPAH 10 wt% (20 nm) / DTASI (20 nm) / 4 CZPBP: Flrpic 9 wt% / TPYMB / LiF (0.5 nm) / Al (100 nm)
Part 1: 4CZPBP: Flrpic 9wt% (30nm)
TPYMB (30nm)
Part 2: 4CZPBP: Flrpic 9wt% (20nm)
TPYMB (40nm)
Part 3: 4CZPBP: Flrpic 9wt% (10nm)
TPYMB (50nm)
Like green phosphorescent devices using Ir (ppy) ₃ , light emitting layer (4CZPBP: Flrpic 9 wt%) / electron transport layer (TPYMB) film thicknesses of 30 nm / 30 nm, 20 nm / 40 nm, 10 nm / 50 nm were produced, respectively. And evaluated.
(2) Evaluation of device FIGS. 35 to 39 show voltage-current density, voltage-luminance, voltage-luminous efficiency, voltage-current efficiency, and luminance-current efficiency characteristics, respectively. FIG. 40 shows an EL spectrum at 25 mA / cm ² . Table 8 summarizes the device characteristics. From the voltage-current characteristics of FIG. 35, the current density tends to increase as the light emitting layer becomes thinner. A similar tendency is observed even in a green phosphor element using Ir (ppy) _3, and it is considered that current is likely to be injected because the electron mobility of TPYMB exceeds the electron mobility of the light emitting layer.
In a 10 nm / 50 nm device, the luminous efficiency at 100 cd / m ² is 33.6 lumens / W, and the external quantum efficiency is 20.6%.

Example 12 (Investigation of Flrpic doping concentration of blue phosphorescent device using TPYMB as electron transport material)
(1) Element configuration ITO / TPDPES: TBPAH 10 wt% (20 nm) / DTASI (20 nm) / 4 CZPBP: Flrpic 9 wt%, 13 wt%, 18 wt% (10 nm) / TPYMB (50 nm) / LiF (0.5 nm) / Al (100 nm)
A light emitting layer was fixed at 10 nm, and a device having a Flrpic doping concentration increased from 9 wt% to 13 wt% and 18 wt% was evaluated.
(2) Evaluation of device FIGS. 41 and 42 show logarithmic plots and linear plots of voltage-current density characteristics, and FIGS. 43 to 45 show voltage-luminance, voltage-luminous efficiency, and voltage-current efficiency, respectively. In addition, FIG. 46 shows an EL spectrum at 25 mA / cm ² . Table 9 summarizes the device characteristics. Currently 9wt%, 13wt%, although three types of data 18 wt%, 13 wt% in 100 cd / ^{m 2} o'clock luminous efficiency 38.2 lumens / W, very high efficiency of external quantum efficiency 20.9 percent Luminescence is obtained. The luminous efficiency at 1000 cd / m ² was 8.5 lumens / W at a doping concentration of 9 wt%, but greatly improved to 16.5 lumens / W at 13 wt%.
From the current density characteristics of FIGS. 41 and 42, it can be confirmed that the current injection is the best in the element having a doping concentration of 18 wt%.

¹ H-NMR of tri [4- (3-pyridyl) -mesityl] borane (TPYMB) of Example 1 which is a compound of the present invention is shown. ¹ H-NMR of tri [4- (4-phenyl-3-pyridyl) -mesityl] borane (TPPYMB) of Example 2 which is a compound of the present invention is shown. Tri [4- (3-pyridyl) -mesityl] borane (TPYMB) of Example 1 and tri [4- (4-phenyl-3-pyridyl) -mesityl] borane (TPPYMB) of Example 2 which are compounds of the present invention The UV absorption spectrum of each deposited film is shown. Tri [4- (3-pyridyl) -mesityl] borane (TPYMB) of Example 1 and tri [4- (4-phenyl-3-pyridyl) -mesityl] borane (TPPYMB) of Example 2 which are compounds of the present invention The PL spectrum of each vapor deposition film is shown. Tri [4- (3-pyridyl) -mesityl] borane (TPYMB) of Example 1 and tri [4- (4-phenyl-3-pyridyl) -mesityl] borane (TPPYMB) of Example 2 which are compounds of the present invention The phosphorescence spectrum in 4.2K of each vapor deposition film is shown. It is a graph which shows the voltage-current density characteristic of the organic EL element (□ mark) of Example 4, and the organic EL element (◯ mark) of Comparative Example 1. It is a graph which shows the voltage-luminance characteristic of the organic EL element (□ mark) of Example 4, and the organic EL element of Comparative Example 1 (◯ mark). It is a graph which shows the voltage-luminous efficiency characteristic of the organic EL element (□ mark) of Example 4, and the organic EL element of Comparative Example 1 (◯ mark). It is a graph which shows the voltage-current efficiency characteristic of the organic EL element (□ mark) of Example 4, and the organic EL element (◯ mark) of Comparative Example 1. It is a graph which shows the voltage-current density characteristic of the organic EL element of Example 5 (□ mark) and the organic EL element of Comparative Example 2 (◯ mark). It is a graph which shows the voltage-luminance characteristic of the organic EL element (□ mark) of Example 5, and the organic EL element of Comparative Example 2 (◯ mark). It is a graph which shows the voltage-luminous efficiency characteristic of the organic EL element (□ mark) of Example 5, and the organic EL element of Comparative Example 2 (◯ mark). It is a graph which shows the voltage-current efficiency characteristic of the organic EL element of Example 5 (□ mark) and the organic EL element of the comparative example 2 (◯ mark). The EL spectrum of the organic EL element of Example 5 (dotted line) and the organic EL element of Comparative Example 2 (solid line) is shown. The EL spectrum of the 300-450 nm part of the organic EL element of Example 5 (dotted line) and the organic EL element of Comparative Example 2 (solid line) is enlarged and displayed. It is a graph which shows each voltage-current density characteristic of the 1 of Example 6 (circle mark), the 2 (square mark), and the 3 (triangle mark). It is a graph which shows each voltage-brightness characteristic of the 1 of Example 6 (circle mark), the 2 (square mark), and the 3 (triangle | delta) mark. It is a graph which shows each voltage-luminous efficiency characteristic of the 1 of Example 6 (circle mark), the 2 (square mark), and the 3 (triangle mark). It is a graph which shows each voltage-current efficiency characteristic of the 1 of Example 6 (circle mark), the 2 (square mark), and the 3 (triangle mark). It is a graph which shows the brightness | luminance-current density efficiency characteristic of the 1 of Example 6, (circle), the 2 (square), and the 3 (triangle | delta). It is a graph which shows the EL spectrum at the time of 25 mA / cm < ² > of each of the 1 of Example 6 (solid line), the 2 (dotted line), and the 3 (broken line). It is a graph which shows each voltage-current density characteristic (logarithm) of Example 7 (circle mark), Example 8 (square mark), and Example 9 (triangle | delta). It is a graph which shows each voltage-current density characteristic (linear) of Example 7 (circle mark), Example 8 (square mark), and Example 9 (triangle | delta). It is a graph which shows each voltage-luminance characteristic (logarithm) of Example 7 (circle mark), Example 8 (square mark), and Example 9 (triangle | delta). It is a graph which shows each voltage-luminance characteristic (linear) of Example 7 (circle mark), Example 8 (square mark), and Example 9 (triangle | delta). It is a graph which shows each voltage-luminous efficiency characteristic of Example 7 (circle mark), Example 8 (square mark), and Example 9 (triangle | delta). It is a graph which shows each voltage-current efficiency characteristic of Example 7 (circle mark), Example 8 (square mark), and Example 9 (triangle | delta). It is a graph which shows EL spectrum at the time of 25 mA / cm < ² > of Example 7 (solid line), Example 8 (dotted line), and Example 9 (broken line), respectively. It is a graph which shows each voltage-current density characteristic of Example 10 (-mark) and Comparative Example 3 (-mark). It is a graph which shows each voltage-luminance characteristic of Example 10 (-mark) and the comparative example 3 ((circle) mark). It is a graph which shows each voltage-luminous efficiency characteristic of Example 10 (-mark) and the comparative example 3 ((circle) mark). It is a graph which shows each voltage-current efficiency characteristic of Example 10 (square) and Comparative Example 3 (circle). It is a graph which shows the EL spectrum at the time of 25 mA / cm < ² > of each of Example 10 (dotted line) and the comparative example 3 (solid line). The EL spectra of the portion of 300 to 450 nm in Example 10 (dotted line) and Comparative Example 3 (solid line) are enlarged and displayed. It is a graph which shows each voltage-current density characteristic (logarithm) of the 1 of Example 11 (circle mark), the 2 (square mark), and the 3 (triangle mark). It is a graph which shows each voltage-brightness characteristic of the 1 of Example 11 (circle mark), the 2 (square mark), and the 3 (triangle | delta) mark. It is a graph which shows each voltage-luminous efficiency characteristic of the 1 of Example 11 (circle mark), the 2 (square mark), and the 3 (triangle mark). It is a graph which shows each voltage-current efficiency characteristic of the 1 of Example 11 (circle mark), the 2 (square mark), and the 3 (triangle mark). It is a graph which shows the luminance-current efficiency characteristic of Example 1 (No. 1), No. 2 (D), and No. 3 (A). It is a graph which shows the EL spectrum at the time of 25 mA / cm < ² > of each of the 1 of Example 11 (thick line), the 2 (thin line), and the 3 (dotted line). It is a graph which shows each voltage-current density characteristic (logarithm) of three organic EL elements of Flrpic dope density | concentration of Example 12 of 9 wt%, 13 wt%, and 18 wt%. It is a graph which shows each voltage-current density characteristic (linear) of three organic EL elements of Flrpic dope density | concentration of Example 12 of 9 wt%, 13 wt%, and 18 wt%. It is a graph which shows each voltage-luminance characteristic of three organic EL elements of Flrpic dope density | concentration of Example 12 of 9 wt%, 13 wt%, and 18 wt%. It is a graph which shows each voltage-luminous efficiency characteristic of three organic EL elements of Flrpic dope density | concentration of Example 12 of 9 wt%, 13 wt%, and 18 wt%. It is a graph which shows each voltage-current efficiency characteristic of three organic EL elements of Flrpic dope density | concentration of Example 12 of 9 wt%, 13 wt%, and 18 wt%. It is a graph which shows the EL spectrum at 25 mA / cm < ² > of each of three organic EL elements of Flrpic dope density | concentration of Example 12 of 9 wt% (solid line), 13 wt% (dotted line), and 18 wt% (dashed line). 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. 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

DESCRIPTION OF SYMBOLS 1 Substrate 2 Anode 3 Light emitting layer 4 Cathode 5 Hole transport layer 6 Electron transport layer 7 Hole injection layer 8 Electron injection layer 9 Hole block layer

Claims (10)

The following general formula (1)
The following general formula (2)
The following general formula (3)
The following general formula (4)
The following general formula (5)
And the following general formula (6)
[R ^{1 to} R ¹⁴ in the formulas in the general formulas (1) to (6) are hydrogen, a linear or branched alkyl group having 1 to 20 carbon atoms, or a linear or branched alkoxy group having 1 to 20 carbon atoms. Group, an alkylamino group having a linear or branched alkyl group having 1 to 20 carbon atoms, an aryl group that may have a linear or branched alkyl group having 1 to 20 carbon atoms as a substituent, or 1 to 20 carbon atoms Independently from the group consisting of an aryloxy group which may have a linear or branched alkyl group as a substituent and an arylamino group which may have a linear or branched alkyl group of 1 to 20 carbon atoms as a substituent. Ar is an arylene group which may have a single bond or a linear or branched alkyl group having 1 to 20 carbon atoms as a substituent, Ar ′ is nitrogen, sulfur or oxygen. (As a substituent, it may also have a linear or branched alkyl group having 1 to 20 carbon atoms) a heteroaryl group having a hetero element selected from the group consisting of a. ]
A triarylboron derivative selected from the group consisting of:   The triarylboron derivative according to claim 1, which has a wide energy gap (Eg) of 3.4 eV or more.   The triarylboron derivative according to claim 1 or 2, which exhibits an emission edge of a low-temperature phosphorescence spectrum at a wavelength shorter than 500 nm.   The triarylboron derivative according to any one of claims 1 to 3, wherein Ar 'in the general formulas (1) to (6) is a pyridyl group.   Ar in general formula (1)-(6) is a single bond or a phenylene group, The triaryl boron derivative in any one of Claims 1-4.   The Ar in the general formulas (1), (2), (4), (5), (6) is bonded to the 3′-position and / or the 5′-position. Triaryl boron derivatives.   An organic electroluminescence device comprising the triarylboron derivative according to claim 1.   An organic electroluminescence device, wherein the triarylboron derivative according to claim 1 is used as an electron transport material.   An organic electroluminescence device comprising the triarylboron derivative according to claim 2 and a phosphorescent material in combination. An organic electroluminescence device comprising the triarylboron derivative according to claim 3 and a phosphorescent material in combination.