JP2017022194A - Material for organic electroluminescence element and organic electroluminescence element using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a material for organic electroluminescence element of high luminous efficiency, and an organic electroluminescence element using the same.SOLUTION: A material for organic electroluminescence element is represented by following general formula (1). (In the general formula (1), R represents an aromatic substituent group).SELECTED DRAWING: None

Description

  The present invention relates to a material for an organic electroluminescent element and an organic electroluminescent element using the same. In particular, the present invention relates to a hole transport material for an organic electroluminescence device having a high luminous efficiency and a long lifetime, and an organic electroluminescence device using the material.

  In recent years, an organic electroluminescence display (Organic Electroluminescence Display) has been actively developed as an image display device. Unlike a liquid crystal display device or the like, an organic EL display device causes a light emitting material containing an organic compound in a light emitting layer to emit light by recombining holes and electrons injected from an anode and a cathode in the light emitting layer. This is a so-called self-luminous display device to be realized.

  Examples of the organic electroluminescence element (organic EL element) include an anode, a hole transport layer disposed on the anode, a light emitting layer disposed on the hole transport layer, an electron transport layer disposed on the light emitting layer, and An organic electroluminescence element composed of a cathode disposed on an electron transport layer is known. Holes are injected from the anode, and the injected holes move through the hole transport layer and are injected into the light emitting layer. On the other hand, electrons are injected from the cathode, and the injected electrons move through the electron transport layer and are injected into the light emitting layer. Excitons are generated in the light emitting layer by recombination of holes and electrons injected into the light emitting layer. An organic electroluminescence element emits light using light generated by radiation deactivation of its excitons. The organic electroluminescence element is not limited to the above-described configuration, and various modifications can be made.

  In applying an organic electroluminescent element to a display device, high efficiency of the organic electroluminescent element is required. In particular, in the blue light emitting region, the driving voltage of the organic electroluminescence element is higher than in the green light emitting region and the red light emitting region, so that the light emission efficiency is low, and the device deterioration is quick because the driving voltage is high. It is hard to say that the lifetime of In order to achieve a long lifetime of the organic electroluminescence element, the hole transport layer has been studied for stabilization, stabilization, and improvement in durability.

  As a hole transport material used for the hole transport layer, various compounds such as aromatic amine compounds are known, but there is a problem in device lifetime. As an advantageous material for extending the lifetime of an element, an amine derivative in which a heteroaryl ring is substituted in an aromatic amine compound has been proposed (Patent Documents 1 and 2). However, it is difficult to say that organic EL devices using these materials have a sufficient light emission lifetime, and at present, organic EL devices that can be driven at a higher efficiency and lower voltage and have a longer light emission lifetime are desired. It is rare. In particular, since the light emission efficiency of the organic EL element is lower in the blue light emission region than in the red light emission region and the green light emission region, improvement in light emission efficiency and longer life are required.

JP 2009-267255 A JP 2009-029726 A

  This invention solves the above-mentioned problem, Comprising: It aims at providing a long life organic electroluminescent element material and an organic electroluminescent element using the same.

  In particular, the present invention relates to a material for an organic electroluminescence device having a high light emission efficiency and a long lifetime, which is used for at least one of the laminated films disposed between the light emitting layer and the anode in the green to blue light emitting region, and the same. An object of the present invention is to provide an organic electroluminescence device using the above.

According to one embodiment of the present invention, a material for an organic electroluminescence device represented by the following general formula (1) is provided.

[In general formula (1), R is selected from the following general formulas (2), (3), and (4);




In the general formulas (1), (2), (3), and (4), Ar _{1 to} Ar ₂ are substituted or unsubstituted alkyl groups having 1 to 30 carbon atoms, and substituted or unsubstituted aryl groups having 6 to 30 carbon atoms. A group, a silyl group, a deuterium atom or a hydrogen atom, Ar ₃ is a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, substituted or unsubstituted A substituted aryl group having 6 to 30 carbon atoms, a silyl group, or a deuterium atom, adjacent Ar ₃ may form a ring, and Ar ₄ is substituted or unsubstituted with a substituted or unsubstituted benzene ring A monovalent substituent consisting of any one of the above naphthalene rings, a silyl group, a deuterium atom or a hydrogen atom, Ar ₅ is a silyl group, a deuterium atom or a hydrogen atom, and L ₁ or L ₂ is a single atom. Bond or ring forming carbon number 6 or more and 30 or less A divalent group of the lower unsubstituted arylene group, a and b are integers of 0 or more and 7 or less, c is an integer of 0 or more and 5 or less, d is an integer of 0 or more and 5 or less, e Is an integer of 0 or more and 5 or less, n and m are 1 or 2, and the three substituents bonded to the nitrogen atom in the general formula (1) are not all the same, and the general formula (1) Of the three substituents bonded to the nitrogen atom, no more than one naphthyl group is present. ]

  The organic electroluminescent device material according to an embodiment of the present invention has an m-phenylene group or o-phenylene group and a naphthyl group at the amine site, so that the planarity of the whole molecule is lost and the amorphous property is improved. Thereby, the light emission efficiency and lifetime of an organic electroluminescent element can be improved.

In the general formula (1), R may be any one of substituents represented by the following structural formulas (R-1) to (R-12).

  The material for an organic electroluminescence element according to one embodiment of the present invention can improve the lifetime of the organic electroluminescence element.

  According to an embodiment of the present invention, there is provided an organic electroluminescence device comprising at least one layer of the material for an organic electroluminescence device.

  The organic electroluminescent element which concerns on one Embodiment of this invention can implement | achieve high luminous efficiency and long lifetime by including the said organic electroluminescent element material in at least one layer.

  According to an embodiment of the present invention, there is provided an organic electroluminescence device comprising the organic electroluminescence device material in at least one layer of a laminated film disposed between a light emitting layer and an anode.

  An organic electroluminescent device according to an embodiment of the present invention includes the material for an organic electroluminescent device in at least one of the laminated films disposed between the light emitting layer and the anode. Long service life can be realized.

  ADVANTAGE OF THE INVENTION According to this invention, the organic electroluminescent element material which implement | achieves high luminous efficiency and long lifetime, and an organic electroluminescent element using the same can be provided. In addition, the material for an organic electroluminescence device of the present invention has an m-phenylene group or o-phenylene group and a naphthyl group at the amine site, so that the planarity of the whole molecule is lost and the amorphousness is improved. Improved efficiency. In addition, by introducing a carrier-resistant naphthyl group via phenylene and securing conjugation around the nitrogen atom, it is possible to stabilize the radical state during hole injection and achieve a long life. it can. Such an effect is particularly remarkable in the green light emission region to the blue light emission region.

It is the schematic which shows the organic electroluminescent element 100 which concerns on one Embodiment of this invention. It is the schematic which shows the organic electroluminescent element 200 which concerns on one Embodiment of this invention.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the organic electroluminescence device material of the present invention has an m-phenylene group, an o-phenylene group, or a naphthyl group, thereby providing planarity of the whole molecule. As a result, the efficiency was improved by improving the amorphous nature. In addition, by introducing a carrier-resistant naphthyl group via phenylene and securing conjugation around the nitrogen atom, it is possible to stabilize the radical state during hole injection and achieve a long life. I found out that I can do it.

  Hereinafter, with reference to drawings, the material for organic electroluminescent elements concerning the present invention and the organic electroluminescent element using the same are explained. However, the organic electroluminescent element material of the present invention and the organic electroluminescent element using the same can be implemented in many different modes, and are limited to the description of the embodiments described below. It is not a thing. Note that in the drawings referred to in this embodiment, the same portions or portions having similar functions are denoted by the same reference numerals, and repetitive description thereof is omitted.

The organic electroluminescent element material according to the present invention is an amine compound represented by the following general formula (1):

[In general formula (1), R is selected from the following general formulas (2), (3), and (4);




In the general formulas (1), (2), (3), and (4), Ar _{1 to} Ar ₂ are substituted or unsubstituted alkyl groups having 1 to 30 carbon atoms, and substituted or unsubstituted aryl groups having 6 to 30 carbon atoms. A group, a silyl group, a deuterium atom or a hydrogen atom, Ar ₃ is a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, substituted or unsubstituted A substituted aryl group having 6 to 30 carbon atoms, a silyl group, or a deuterium atom, adjacent Ar ₃ may form a ring, and Ar ₄ is substituted or unsubstituted with a substituted or unsubstituted benzene ring A monovalent substituent consisting of any one of the above naphthalene rings, a silyl group, a deuterium atom or a hydrogen atom, Ar ₅ is a silyl group, a deuterium atom or a hydrogen atom, and L ₁ or L ₂ is a single atom. Bond or ring forming carbon number 6 or more and 30 or less A divalent group of the lower unsubstituted arylene group, a and b are integers of 0 or more and 7 or less, c is an integer of 0 or more and 5 or less, d is an integer of 0 or more and 5 or less, e is an integer of 0 or more and 5 or less, n and m are 1 or 2, and the three substituents bonded to the nitrogen atom in the general formula (1) are not all the same, and the general formula (1 ) The number of naphthyl groups in each of the three substituents bonded to the nitrogen atom is 1 or less. ]

Examples of the alkyl group having 1 to 30 carbon atoms used for Ar _{1 to} Ar ₃ in the general formulas (1) and (2) include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, s-butyl group, Isobutyl group, t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 2-hydroxyisobutyl group, 1,2-dihydroxyethyl group, 1,3-dihydroxyisopropyl group, 2,3-dihydroxy-t-butyl group, 1,2,3-trihydroxypropyl group, chloromethyl group, 1-chloroethyl group, 2-chloroethyl Group, 2-chloroisobutyl group, 1,2-dichloroethyl group, 1,3-dichloroisopropyl group, 2,3-dichloro-t-butyl group, 1,2, -Trichloropropyl group, bromomethyl group, 1-bromoethyl group, 2-bromoethyl group, 2-bromoisobutyl group, 1,2-dibromoethyl group, 1,3-dibromoisopropyl group, 2,3-dibromo-t-butyl group 1,2,3-tribromopropyl group, iodomethyl group, 1-iodoethyl group, 2-iodoethyl group, 2-iodoisobutyl group, 1,2-diiodoethyl group, 1,3-diiodoisopropyl group, 2,3 -Diiodo-t-butyl group, 1,2,3-triiodopropyl group, cyanomethyl group, 1-cyanoethyl group, 2-cyanoethyl group, 2-cyanoisobutyl group, 1,2-dicyanoethyl group, 1,3- Dicyanoisopropyl group, 2,3-dicyano-t-butyl group, 1,2,3-tricyanopropyl group, nitromethyl group, 1-nitroe Group, 2-nitroethyl group, 2-nitroisobutyl group, 1,2-dinitroethyl group, 1,3-dinitroisopropyl group, 2,3-dinitro-t-butyl group, 1,2,3-trinitropropyl Group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, 4-methylcyclohexyl group, 1-adamantyl group, 2-adamantyl group, 1-norbornyl group, 2-norbornyl group and the like. It is not something.

Examples of the substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms used for Ar ₃ in the general formula (2) include methoxy group, ethoxy group, propyloxy group, isopropyloxy group, butoxy group, isobutoxy group, sec- Butoxy group, tert-butoxy group, pentyloxy group, isopentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, 2-ethylhexyloxy group, decyloxy group, dodecyloxy group, octadecyloxy group, ethoxycarbonylmethyl group 2-ethylhexyloxycarbonylmethyloxy group, aminocarbonylmethyloxy group, N, N-dibutylaminocarbonylmethyloxy group, N-methylaminocarbonylmethyloxy group, N-ethylaminocarbonylmethyloxy group, N-octyl Examples thereof include, but are not limited to, aminocarbonylmethyloxy group, N-methyl-N-benzylaminocarbonylmethyloxy group, benzyloxy group, cyanomethyloxy group and the like.

Examples of the aryl group having 6 to 30 ring carbon atoms used for Ar _{1 to} Ar ₃ in the general formulas (1) and (2) include phenyl group, naphthyl group, anthracenyl group, phenanthryl group, biphenyl group, terphenyl group, quarter A phenyl group, a fluorenyl group, a triphenylene group, a biphenylene group, a pyrenyl group, a benzofluoranthenyl group, a chrycenyl group, a phenylnaphthyl group, a naphthylphenyl group, and the like, and a phenyl group, a naphthyl group, and a biphenyl group are particularly preferable. The aryl group having 6 to 30 ring carbon atoms used for Ar _{1 to} Ar ₃ is not limited thereto.

The silyl group used for Ar _{1 to} Ar ₃ may be a trialkylsilyl group, a triarylsilyl group, a monoalkyldiarylsilyl group, a dialkylmonoarylsilyl group, such as a trimethylsilyl group or a triphenylsilyl group. Etc.

When Ar _{1 to} Ar ₃ in the general formula (1) have a substituent, examples of the substituent include alkyl groups such as a methyl group, an ethyl group, a propyl group, a pentyl group, and a hexyl group, a phenyl group, and a biphenyl group. And aryl groups such as a naphthyl group. Ar _{1 to} Ar ₃ may each have a plurality of substituents. The substituents may be connected to each other to form a saturated or unsaturated ring.

Examples of the arylene group having 6 to 12 ring carbon atoms used for L _{1 to} L ₂ in the general formula (1) include, but are not limited to, a phenylene group, a biphenylene group, and a naphthylene group. In the general formula (1), at least one of L _{1 to} L ₃ is preferably an arylene group, and particularly preferably a phenylene group.

  The amine compound which is the material for an organic electroluminescence device of the present invention represented by the general formula (1) shown above has an m-phenylene group, an o-phenylene group or a naphthyl group, so that the planarity of the whole molecule is lost. Higher efficiency can be realized by improving the amorphous property.

  In addition, by introducing a carrier-resistant naphthyl group via phenylene and securing conjugation around the nitrogen atom, it is possible to stabilize the radical state during hole injection and improve the lifetime. it can.

Ar _{1 to} Ar ₂ in the general formula (1) are more preferably aryl groups having 6 to 10 ring carbon atoms. As the aryl group having 6 to 10 ring carbon atoms used for Ar _{1 to} Ar ₂ in the general formula (1), a phenyl group and a naphthyl group are particularly preferable.

The silyl group used for Ar ₄ in the general formula (3) is the same as described in Ar _{1 to} Ar ₃ .

The silyl group used for Ar ₅ in the general formula (4) is the same as described for Ar _{1 to} Ar ₄ .

  The organic electroluminescent element material according to the present invention is a substance represented by the following structural formula as an example.

  As the organic electroluminescent element material according to the present invention, the compound 21, the compound 77, the compound 79, and the compound 96 are particularly preferable.

  The organic electroluminescent element material according to the present invention may be included in at least one of a plurality of organic layers constituting the organic electroluminescent element. In particular, it may be significantly contained in at least one of the laminated films disposed between the light emitting layer and the anode of the organic electroluminescence element.

  As described above, the organic electroluminescent element material according to the present invention has an m-phenylene group, an o-phenylene group, or a naphthyl group at the amine site, so that the planarity of the whole molecule is broken and the amorphous property is improved. Can achieve high efficiency. In addition, by introducing a naphthyl group having carrier resistance through phenylene and ensuring conjugation around the nitrogen atom, the radical state at the time of hole injection can be stabilized, and a long life can be achieved.

(Organic electroluminescence device)
The organic electroluminescent element using the organic electroluminescent element material according to the present invention will be described. FIG. 1 is a schematic view showing an organic electroluminescence device 100 according to an embodiment of the present invention. The organic electroluminescence device 100 includes, for example, a substrate 102, an anode 104, a hole injection layer 106, a hole transport layer 108, a light emitting layer 110, an electron transport layer 112, an electron injection layer 114, and a cathode 116. In one embodiment, the organic electroluminescent element material according to the present invention can be used in at least one of the laminated films disposed between the light emitting layer and the anode.

  Here, as an example, the case where the organic electroluminescent element material according to the present invention is used for the hole transport layer 108 will be described.

  The substrate 102 may be a flexible substrate such as a transparent glass substrate or a semiconductor substrate resin made of silicon or the like.

The anode 104 is disposed on the substrate 102 and can be formed using indium tin oxide (In ₂ O ₃ —SnO ₂ : ITO), indium zinc oxide (In ₂ O ₃ —ZnO), or the like. .

The hole injection layer (HIL) 106 can be formed on the anode 104 with a thickness of 10 nm to 150 nm using a known material. For example, triphenylamine-containing polyetherketone (TPAPEK), 4-isopropyl-4′-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate (PPBI), N, N′-diphenyl-N, N′-bis- [4 -(Phenyl-m-tolyl-amino) -phenyl] -biphenyl-4,4'-diamine (DNTPD), phthalocyanine compounds such as copper phthalocyanine, 4,4 ', 4 "-tris (3-methylphenylphenylamino) Triphenylamine (m-MTDATA), N, N′-di (1-naphthyl) -N, N′-diphenylbenzidine (NPB), 4,4 ′, 4 ″ -tris {N
, N-diphenylamino} triphenylamine (TDATA), 4,4 ′, 4 ″ -tris (N,
N-2-naphthylphenylamino) triphenylamine (2-TNATA), polyaniline / dodecylbenzenesulfonic acid (PANI / DBSA), poly (3,4-ethylenedioxythiophene) / poly (4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (PANI / CSA), polyaniline / poly (4-styrenesulfonate) (PANI / PSS), or the like.

  The hole transport layer (HTL) 108 is formed on the hole injection layer 106 with a thickness of 3 nm or more and 100 nm or less using the organic electroluminescence element material according to the present invention. The hole transport layer 108 containing the organic electroluminescence element material according to the present invention may be formed by, for example, vacuum deposition.

  The light emitting layer (EL) 110 is formed on the hole transport layer 108 with a thickness of 10 nm to 60 nm using a known host material. As a known host material used for the light emitting layer 110, for example, a condensed polycyclic aromatic derivative is preferably contained, and is selected from anthracene derivatives, pyrene derivatives, fluorarentene derivatives, chrysene derivatives, benzoanthracene derivatives, and triphenylene derivatives. It is preferred that In particular, the light emitting layer 110 preferably contains an anthracene derivative or a pyrene derivative. As an anthracene derivative used for the light emitting layer 110, the compound shown by the following general formula (2) is mentioned.

In the formula (5), R _{11 to} R ₂₀ are substituted or unsubstituted aryl groups having 6 to 30 ring carbon atoms, substituted or unsubstituted heteroaryl groups having 1 to 30 ring carbon atoms, and 1 carbon atom. These are an alkyl group, a silyl group, a hydrogen atom or a deuterium atom having 15 or less. G and h are integers of 0 or more and 5 or less. A plurality of adjacent R _{11 to} R ₂₀ may be bonded to form a saturated or unsaturated ring.

Examples of the substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms in R _{11 to} R ₂₀ include benzothiazolyl group, thiophenyl group, thienothiophenyl group, thienothienothiophenyl group, benzothiophenyl group, and benzofuryl. Group, dibenzothiophenyl group, dibenzofuryl group, N-arylcarbazolyl group, N-heteroarylcarbazolyl group, N-alkylcarbazolyl group, phenoxazyl group, phenothiazyl group, pyridyl group, pyrimidyl group, triazyl group , Quinolinyl group, quinoxalyl group and the like, but are not limited thereto.

Examples of the substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms in R _{11 to} R ₂₀ include benzothiazolyl group, thiophenyl group, thienothiophenyl group, thienothienothiophenyl group, benzothiophenyl group, and benzofuryl. Group, dibenzothiophenyl group, dibenzofuryl group, N-arylcarbazolyl group, N-heteroarylcarbazolyl group, N-alkylcarbazolyl group, phenoxazyl group, phenothiazyl group, pyridyl group, pyrimidyl group, triazyl group , Quinolinyl group, quinoxalyl group and the like, but are not limited thereto.

The alkyl group having 1 to 15 carbon atoms for use in R ₁₁ to R _20, a methyl group, an ethyl group, a propyl group, an isopropyl group, n- butyl group, s- butyl, isobutyl, t- butyl group N-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 2-hydroxyisobutyl group, 1,2-dihydroxyethyl group 1,3-dihydroxyisopropyl group, 2,3-dihydroxy-t-butyl group, 1,2,3-trihydroxypropyl group, chloromethyl group, 1-chloroethyl group, 2-chloroethyl group, 2-chloroisobutyl group 1,2-dichloroethyl group, 1,3-dichloroisopropyl group, 2,3-dichloro-t-butyl group, 1,2,3-trichloropropylene Group, bromomethyl group, 1-bromoethyl group, 2-bromoethyl group, 2-bromoisobutyl group, 1,2-dibromoethyl group, 1,3-dibromoisopropyl group, 2,3-dibromo-t-butyl group, 1, 2,3-tribromopropyl group, iodomethyl group, 1-iodoethyl group, 2-iodoethyl group, 2-iodoisobutyl group, 1,2-diiodoethyl group, 1,3-diiodoisopropyl group, 2,3-diiodo- t-butyl group, 1,2,3-triiodopropyl group, aminomethyl group, 1-aminoethyl group, 2-aminoethyl group, 2-aminoisobutyl group, 1,2-diaminoethyl group, 1,3- Diaminoisopropyl group, 2,3-diamino-t-butyl group, 1,2,3-triaminopropyl group, cyanomethyl group, 1-cyanoethyl group, 2-cyanoethyl Group, 2-cyanoisobutyl group, 1,2-dicyanoethyl group, 1,3-dicyanoisopropyl group, 2,3-dicyano-t-butyl group, 1,2,3-tricyanopropyl group, nitromethyl group, 1-nitroethyl group, 2-nitroethyl group, 2-nitroisobutyl group, 1,2-dinitroethyl group, 1,3-dinitroisopropyl group, 2,3-dinitro-t-butyl group, 1,2,3-tri Examples thereof include nitropropyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, 4-methylcyclohexyl group, 1-adamantyl group, 2-adamantyl group, 1-norbornyl group, 2-norbornyl group, etc. It is not limited to.

  The anthracene derivative used for the light emitting layer 110 of the organic electroluminescence device according to the present invention is a substance represented by the following structural formula as an example.

  The light-emitting layer 110 has a styryl derivative (for example, 1,4-bis [2- (3-N-ethylcarbazoryl) vinyl] benzene (BCzVB), 4- (di-p-tolylamino) -4 ′-[( di-p-tolylamino) styryl] stilbene (DPAVB), N- (4-((E) -2- (6-((E) -4- (diphenylamino) styryl) naphthalene-2-yl) vinyl) phenyl- N-phenylbenzenamine (N-BDAVBi)), perylene and its derivatives (for example, 2,5,8,11-Tetra-t-butylperylene (TBP), pyrene and its derivatives (for example, 1,1-dipyrene, 1,4 It may contain a dopant such as -dipyrenylbenzene and 1,4-Bis (N, N-Diphenylamino) pyrene), but is not limited thereto.

The electron transport layer (ETL) 112 has a thickness of 15 nm or more and 50 nm or less on the light-emitting layer 110, and includes, for example, a material having Tris (8-hydroxyquinolinato) aluminum (Alq ₃ ) or a nitrogen-containing aromatic ring (for example, 1,3 , 5-tri [(3-pyridyl) -phen-3-yl] benzene-containing materials such as 2,4,6-tris (3 '-(pyridine-3-yl) biphenyl-3-yl) A material containing a triazine ring such as 1,3,5-triazine and a material containing an imidazole derivative such as 2- (4-N-phenylbenzoimidazolyl-1-ylphenyl) -9,10-dinaphthylanthracene).

  The electron injection layer (EIL) 114 has a thickness of 0.3 nm to 9 nm on the electron transport layer 112 and is formed of a material containing, for example, lithium fluoride (LiF), lithium-8-quinolinate (Liq), or the like. .

  The cathode 116 is disposed on the electron injection layer 114 and is made of a metal such as aluminum (Al), silver (Ag), lithium (Li), magnesium (Mg), calcium (Ca), a mixture thereof, and an oxide. It is formed of a transparent material such as indium tin (ITO) and indium zinc oxide (In2O3-ZnO).

  Each electrode and each layer constituting the organic electroluminescence element according to the present invention described above can be formed by selecting an appropriate film formation method according to the material such as vacuum deposition, sputtering, and various coatings.

  In the organic electroluminescent element 100 according to the present invention, by using the organic electroluminescent element material according to the present invention described above, a hole transport layer capable of realizing high efficiency and long life of the organic electroluminescent element is provided. Can be formed.

  Moreover, in the organic electroluminescent element 100 which concerns on this invention, the organic electroluminescent element material which concerns on this invention mentioned above may be used as a material of a positive hole injection layer. As described above, the organic electroluminescent element material according to the present invention is included in at least one of a plurality of organic layers constituting the organic electroluminescent element, thereby improving the efficiency and long life of the organic electroluminescent element. Can be realized.

  The material for an organic electroluminescence element according to the present invention can also be applied to an active matrix organic electroluminescence light emitting device using a TFT.

(Production method)
The organic electroluminescent element material according to the present invention can be synthesized, for example, as follows.

Method for synthesizing compound 21

(Synthesis of Compound A)
In an Ar atmosphere, a 300 mL three-necked flask was charged with 8.00 g of 1-naphthylboronic acid, 11.9 g of 1-iodo-3-bromobenzene, 1.61 g of Pd (PPh ₃ ) ₄ and potassium carbonate. 12.8 g was added, and the mixture was heated and stirred at 90 ° C. for 6.5 hours in a mixed solvent of 150 mL of toluene and 30 mL of water. After air cooling, water was added to separate the organic layer, and the solvent was distilled off. The obtained crude product was purified by silica gel column chromatography (using a mixed solvent of toluene and hexane) and then recrystallized with a mixed solvent of toluene / hexane to obtain 12.5 g of Compound A as a transparent liquid (yield 91 %)Obtained. The molecular weight of Compound A measured by FAB-MS measurement was 283.

(Synthesis of Compound B)
Under Ar atmosphere, 10.0 g of compound A and 7.74 g of 4- (4,4,5,5-tetramethyl-1,3,2-dioxaboran-2-yl) aniline in a 1 L three-necked flask Then, 2.04 g of Pd (PPh ₃ ) ₄ and 13.8 g of potassium phosphate were added, and the mixture was heated and stirred at 90 ° C. for 6.5 hours in a mixed solvent of 300 mL of toluene and 75 mL of water. After air cooling, water was added to separate the organic layer, and the solvent was distilled off. The obtained crude product was purified by silica gel column chromatography (using a mixed solvent of dichloromethane and hexane) to obtain 9.36 g (yield 90%) of Compound B as a yellow solid. The molecular weight of Compound B measured by FAB-MS measurement was 295.

(Synthesis of Compound 21)
Under Ar atmosphere, in a 500 mL three-necked flask, 8.20 g of compound B, 17.3 g of 1-(-4-bromophenyl) naphthalene, 1.11 g of Pd ₂ (dba) ₃ , tri-tert-butyl 1.50 g of phosphine and 13.3 g of NaOtBu were added, and the mixture was heated to reflux with stirring in a 200 mL toluene mixed solvent for 3 hours. After air cooling, water was added to separate the organic layer, and the solvent was distilled off. The obtained crude product was purified by silica gel column chromatography (using a mixed solvent of toluene and hexane) and then recrystallized with a toluene / ethanol mixed solvent to obtain 15.9 g of a white solid compound 21 (yield 82%). )Obtained.

The molecular weight of Compound 21 measured by FAB-MS measurement was 700. Further, the chemical shift value δ of the compound 21 measured by ¹ H-NMR (CDCl ₃ ) measurement is 8.06 (d, 2H, J = 7.20 Hz), 7.97 (d, 1H, J = 8). .10 Hz), 7.94-7.84 (m, 6H), 7.68 (s, 1H), 7.71-7.63 (m, 3H), 7.58-7.43 (m, 18H) ), 7.38-7.33 (m, 6H).

  The organic electroluminescent element material according to the present invention can be synthesized, for example, as follows.

Method for synthesizing compound 77

(Synthesis of Compound C)
In an Ar atmosphere, a 300 mL three-necked flask was charged with 14.0 g of phenylboronic acid, 11.9 g of 3-bromo-4-chloroaniline, 1.65 g of Pd (PPh ₃ ) _4, and 13.5 g of potassium carbonate. 3 g was added, and the mixture was heated and stirred at 90 ° C. for 6.5 hours in a mixed solvent of 150 mL of toluene and 30 mL of water. After air cooling, water was added to separate the organic layer, and the solvent was distilled off. The obtained crude product was purified by silica gel column chromatography (using a mixed solvent of toluene and hexane), and then recrystallized with a mixed solvent of toluene / hexane to obtain 9.41 g of Compound C as a transparent liquid (yield 80 %)Obtained. The molecular weight of Compound C measured by FAB-MS measurement was 204.

(Synthesis of Compound D)
In a 200 mL three-necked flask under an Ar atmosphere, 1.09 g of 1-naphthylboronic acid, 2.51 g of compound C, 0.08 g of palladium acetate, 2-dicyclohexylphosphino-2 ', 6'-dimethoxybiphenyl 0.27 g and 4.53 g of potassium phosphate were added, and the mixture was heated and stirred at 100 ° C. for 6.5 hours in a mixed solvent of 50 mL of toluene and 13 mL of water. After air cooling, water was added to separate the organic layer, and the solvent was distilled off. The obtained crude product was purified by silica gel column chromatography (using a mixed solvent of toluene and hexane), and then recrystallized with a mixed solvent of toluene / hexane to obtain 3.92 g of Compound D as a transparent liquid (yield 74 %)Obtained. The molecular weight of Compound D measured by FAB-MS measurement was 295.

(Synthesis of Compound 71)
Under Ar atmosphere, in a 500 mL three-necked flask, 8.20 g of compound D, 17.0 g of 1-(-4-bromophenyl) naphthalene, 1.11 g of Pd ₂ (dba) ₃ , tri-tert-butyl 1.50 g of phosphine and 13.3 g of NaOtBu were added, and the mixture was heated to reflux with stirring in a 200 mL toluene mixed solvent for 3 hours. After air cooling, water was added to separate the organic layer, and the solvent was distilled off. The obtained crude product was purified by silica gel column chromatography (using a mixed solvent of toluene and hexane) and then recrystallized with a mixed solvent of toluene / ethanol to obtain 16.3 g of a white solid compound 71 (yield 84%). )Obtained.

The molecular weight of Compound 71 measured by FAB-MS measurement was 700. The chemical shift value δ of Compound 71 measured by ¹ H-NMR (CDCl ₃ ) measurement is 8.03 (d, 2H, J = 7.20 Hz), 7.99 (d, 1H, J = 8). .10 Hz), 7.97-7.86 (m, 6H), 7.66 (s, 1H), 7.65-7.61 (m, 3H), 7.58-7.43 (m, 18H) ), 7.37-7.33 (m, 6H).

  The organic electroluminescent element material according to the present invention can be synthesized, for example, as follows.

Method for synthesizing compound 79

(Synthesis of Compound E)
In an Ar atmosphere, in a 300 mL three-necked flask, 10.0 g of 1-naphthylboronic acid, 11.9 g of 3-bromo-4-chloroaniline, 1.65 g of Pd (PPh ₃ ) ₄ , and potassium carbonate 13.3 g was added, and the mixture was heated and stirred at 90 ° C. for 6.5 hours in a mixed solvent of 150 mL of toluene and 30 mL of water. After air cooling, water was added to separate the organic layer, and the solvent was distilled off. The obtained crude product was purified by silica gel column chromatography (using a mixed solvent of toluene and hexane), and then recrystallized with a mixed solvent of toluene / hexane to give 10.3 g of Compound E as a yellow liquid (yield 70). %)Obtained. The molecular weight of Compound E measured by FAB-MS measurement was 254.

(Synthesis of Compound F)
In an Ar atmosphere, in a 200 mL three-necked flask, 1.29 g of phenylboronic acid, 2.54 g of compound E, 0.08 g of palladium acetate, and 0 of 2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl .27 g and 4.53 g of potassium phosphate were added, and the mixture was heated and stirred at 100 ° C. for 6.5 hours in a mixed solvent of 50 mL of toluene and 13 mL of water. After air cooling, water was added to separate the organic layer, and the solvent was distilled off. The obtained crude product was purified by silica gel column chromatography (using a mixed solvent of toluene and hexane), and then recrystallized with a mixed solvent of toluene / hexane to obtain 2.00 g of compound F as a pale yellow solid (yield) 68%). The molecular weight of Compound F measured by FAB-MS measurement was 295.

(Synthesis of Compound 79)
In an Ar atmosphere, in a 500 mL three-necked flask, 8.20 g of compound F, 17.0 g of 1-(-4-bromophenyl) naphthalene, 1.11 g of Pd ₂ (dba) ₃ , tri-tert-butyl 1.50 g of phosphine and 13.3 g of NaOtBu were added, and the mixture was heated to reflux with stirring in a 200 mL toluene mixed solvent for 3 hours. After air cooling, water was added to separate the organic layer, and the solvent was distilled off. The obtained crude product was purified by silica gel column chromatography (using a mixed solvent of toluene and hexane), and then recrystallized with a mixed solvent of toluene / ethanol to obtain 17.5 g of a white solid compound 79 (yield 90%). )Obtained.

The molecular weight of Compound 79 measured by FAB-MS measurement was 700. Further, the chemical shift value δ of the compound 79 measured by ¹ H-NMR (CDCl ₃ ) measurement is 8.09 (d, 2H, J = 7.30 Hz), 7.99 (d, 1H, J = 8). .10 Hz), 7.95-7.77 (m, 6H), 7.70 (s, 1H), 7.65-7.61 (m, 3H), 7.58-7.43 (m, 18H) ), 7.40-7.35 (m, 6H).

  The organic electroluminescent element material according to the present invention can be synthesized, for example, as follows.

Method for synthesizing compound 96

(Synthesis of Compound G)
In an Ar atmosphere, a 300 mL three-necked flask was charged with 8.01 g of 1-naphthylboronic acid, 11.8 g of 1-iodo-2-bromobenzene, 1.61 g of Pd (PPh ₃ ) ₄ , and potassium carbonate. 12.8 g was added, and the mixture was heated and stirred at 90 ° C. for 6.5 hours in a mixed solvent of 150 mL of toluene and 30 mL of water. After air cooling, water was added to separate the organic layer, and the solvent was distilled off. The obtained crude product was purified by silica gel column chromatography (using a mixed solvent of toluene and hexane) and then recrystallized with a mixed solvent of toluene / hexane to obtain 12.0 g (yield 90) of compound G as a transparent liquid. %)Obtained. The molecular weight of Compound G measured by FAB-MS measurement was 283.

(Synthesis of Compound H)
Under Ar atmosphere, 10.0 g of compound A and 7.74 g of 4- (4,4,5,5-tetramethyl-1,3,2-dioxaboran-2-yl) aniline in a 1 L three-necked flask Then, 2.04 g of Pd (PPh ₃ ) ₄ and 13.8 g of potassium phosphate were added, and the mixture was heated and stirred at 90 ° C. for 6.5 hours in a mixed solvent of 300 mL of toluene and 75 mL of water. After air cooling, water was added to separate the organic layer, and the solvent was distilled off. The obtained crude product was purified by silica gel column chromatography (using a mixed solvent of dichloromethane and hexane) to obtain 8.84 g (yield 85%) of Compound H as a yellow solid. The molecular weight of Compound H measured by FAB-MS measurement was 295.

(Synthesis of Compound 96)
Under Ar atmosphere, in a 500 mL three-necked flask, 8.20 g of compound B, 17.3 g of 1-(-4-bromophenyl) naphthalene, 1.11 g of Pd ₂ (dba) ₃ , tri-tert-butyl 1.50 g of phosphine and 13.3 g of NaOtBu were added, and the mixture was heated to reflux with stirring in a 200 mL toluene mixed solvent for 3 hours. After air cooling, water was added to separate the organic layer, and the solvent was distilled off. The obtained crude product was purified by silica gel column chromatography (using a mixed solvent of toluene and hexane) and then recrystallized with a mixed solvent of toluene / ethanol to obtain 15.9 g of a white solid compound 96 (yield 82%). )Obtained.

The molecular weight of Compound 96 measured by FAB-MS measurement was 700. Further, the chemical shift value δ of the compound 96 measured by ¹ H-NMR (CDCl ₃ ) measurement is 8.03 (d, 2H, J = 7.20 Hz), 7.97 (d, 1H, J = 8). 0.000), 7.95 (s, 1H) 7.92-7.84 (m, 6H), 7.71-7.66 (m, 3H), 7.58-7.43 (m, 18H) ), 7.39-7.35 (m, 6H).

  Using the above-mentioned compound 21, compound 71, and compound 96 as hole transport materials, organic electroluminescence devices of Examples 1 to 3 were produced by the production method described above.

  Moreover, the organic electroluminescent element of the comparative examples 1 thru | or 5 was produced as a comparative example using the comparative example compounds C1-C5 shown below as a hole transport material.

An organic electroluminescence device 200 according to this example is shown in FIG. In this embodiment, a transparent glass substrate is used as the substrate 202, the anode 204 is formed from ITO having a thickness of 150 nm, the hole injection layer 206 is formed from 2-TNATA having a thickness of 60 nm, and a film having a thickness of 30 nm is formed. A thick hole transport layer 208 is formed, a light emitting layer 210 with a thickness of 25 nm is formed by doping ADN with 3% TBP, an electron transport layer 212 with a thickness of 25 nm is formed with Alq ₃ , and 1 nm is formed with LiF. An electron injection layer 214 having a thickness of 10 nm was formed, and a cathode 216 having a thickness of 100 nm was formed of Al.

About the produced organic electroluminescent element 200, drive voltage, luminous efficiency, and half life were evaluated. The voltage and luminous efficiency are values at a current density of 10 mA / cm ² , and the half-life indicates a luminance half time from an initial luminance of 1,000 cd / m ² . The evaluation results are shown in Table 1.

  As can be seen from the results in Table 1, Examples 1 to 3 show that the use of a hole transport material having a 3- (1-naphthalenyl) phenyl group and a 4- (1-naphthalenyl) phenyl group increases the efficiency and length. It can be seen that the life has been improved. That is, it can be seen that Examples 1 to 3 have a longer life and higher efficiency than Comparative Examples 1 to 5. In Examples 1 and 2, it is considered that very high efficiency is exhibited due to the effect of the m-phenylene group or naphthyl group. The o-phenylene group of Example 3 also contributes to the improvement of amorphousness and achieves high efficiency. As in Examples 1 and 3, the compound having three naphthyl groups resulted in a particularly long device lifetime. On the other hand, Comparative Example 1 has low molecular efficiency due to high molecular symmetry and low amorphousness. In Comparative Example 2, the highly planar dibenzofuranyl group is located away from the nitrogen atom, causing intermolecular interaction and increasing crystallinity, resulting in low efficiency due to low amorphousness. Comparative Example 3 has low efficiency and short life because of high molecular symmetry and low amorphousness. In Comparative Example 4, the presence of the 1,3,5-phenylene group increases the symmetry of the molecule and leads to a reduction in efficiency. In Comparative Example 5, since the naphthyl group was not substituted on the nitrogen atom via phenylene, the overall conjugation length of the compound was short, and there was a problem in the stability of the radical state, and the device had a low lifetime.

  From the results in Table 1, it can be seen that according to the present invention, the planarity of the whole molecule is lost by having an m-phenylene group, o-phenylene group, or naphthyl group, and high efficiency can be realized by improving the amorphous nature. . In addition, by introducing a carrier-resistant naphthyl group via phenylene and securing conjugation around the nitrogen atom, it is possible to stabilize the radical state during hole injection and to achieve a long lifetime. .

  In addition, since the organic electroluminescent element material which concerns on this invention has a wide energy gap, it is also possible to apply to a red area | region and a green area | region.

100 organic EL device, 102 substrate, 104 anode, 106 hole injection layer, 108 hole transport layer, 110 light emitting layer, 112 electron transport layer, 114 electron injection layer, 116 cathode, 200 organic EL device, 202 substrate, 204 anode 206 hole injection layer, 208 hole transport layer, 210 light emitting layer, 212 electron transport layer, 214 electron injection layer, 216 cathode

Claims (4)

The material for organic electroluminescent elements represented by the following general formula (1).
[In general formula (1), R is selected from the following general formulas (2), (3), and (4);

In the general formulas (1), (2), (3), and (4), Ar _{1 to} Ar ₂ are substituted or unsubstituted alkyl groups having 1 to 30 carbon atoms, and substituted or unsubstituted aryl groups having 6 to 30 carbon atoms. A group, a silyl group, a deuterium atom or a hydrogen atom, Ar ₃ is a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, substituted or unsubstituted A substituted aryl group having 6 to 30 carbon atoms, a silyl group, or a deuterium atom, and Ar ₄ is a monovalent group consisting of either a substituted or unsubstituted benzene ring or a substituted or unsubstituted naphthalene ring. A substituent, a silyl group, a deuterium atom or a hydrogen atom; Ar ₅ is a silyl group, a deuterium atom or a hydrogen atom; and L ₁ or L ₂ is a single bond or an unsubstituted carbon having 6 to 30 carbon atoms. A divalent group of an arylene group A and b are integers from 0 to 7, c is an integer from 0 to 5, d is an integer from 0 to 5, e is an integer from 0 to 5, n and m is 1 or 2, and the three substituents bonded to the nitrogen atom in the general formula (1) are not all the same, and in the three substituents bonded to the nitrogen atom in the general formula (1) Each naphthyl group is one or less. ] 2. The compound according to claim 1, wherein R in the formula (1) is a compound represented by any one of substituents represented by the following structural formulas (R-1) to (R-12). Material for organic electroluminescence element.
  The organic electroluminescent element which contains the organic electroluminescent element material of Claim 1 or 2 in at least one layer.   The organic electroluminescent element which contains the organic electroluminescent element material of Claim 1 or 2 in at least one layer of the laminated films arrange | positioned between the light emitting layer and the anode.