KR102402626B1 - A self-organizable polycyclic aromatic compound and an organic electroluminescent element using the same - Google Patents

Abstract

An object of the present invention is to provide an organic EL device having excellent durability.
In order to solve the above problems, the present invention uses a self-organized polycyclic aromatic compound as a material for at least one layer of a plurality of layers constituting an organic EL device, thereby suppressing morphological changes due to heat, thereby reducing changes in driving voltage and luminous efficiency. An organic EL device having excellent durability is provided.

Description

A self-organizable polycyclic aromatic compound and an organic electroluminescent element using the same

The present invention relates to an organic electroluminescent device (organic EL device), which is expected to be used as a thin screen for portable devices and car audio devices, and is also expected for use in thin TVs and as next-generation lighting.

This organic EL element is, for example, an element composed of an anode/hole transport layer/light emitting layer/electron transport layer/cathode. The hole transport layer has a function of transporting holes injected from the anode to the light emitting layer, and one electron transport layer has a function of transporting electrons injected from the cathode to the light emitting layer. It is known that luminous efficiency and durability are improved by inserting these transport layers between the light emitting layer and both electrodes, and studies of organic compounds suitable for each layer are being actively conducted.

For example, anthracene derivatives having a heteroaromatic group such as a pyridine ring in a molecule have been reported as forming a stable electron transport layer that prolongs the device lifetime (Patent Document 1, Patent Document 2, Patent Document 3, Patent Document 4), It does not use self-organization ability.

Developments in anticipation of various effects using molecular self-organization have been reported. As a case in which self-organization is used in the wet process of an organic EL device, light emission is polarized using a material self-organized into a disk shape by hydrogen bonding (Patent Document 5), or an alkyl group is applied to the electrode surface using a silanol group or a thiol group. By self-organizing by covalent bonding, the adhesion is increased to reduce dark spots (Patent Document 6), or by self-organizing on the electrode using a silane compound, the liquid repellency of the surface of the organic ultra-thin film pattern in the inkjet method is improved ( Patent document 7, patent document 8), there exist examples, such as manufacturing by self-organization (patent document 9) of the micropore structure which accommodates each layer of an organic electroluminescent element as if laminated|stacked in order.

Examples of using the self-organization of the wet process other than organic EL devices include π-π stacking using the planarity of aromatic rings and the development of photoconductive materials that utilize the amphiphilic properties of hydrophilic and hydrophobic substituents to form nano-sized structures (patents). literature 10).

Furthermore, in order to achieve stabilization of the amorphous organic film of an organic EL device produced by a dry process, a method of heating a substrate during device fabrication or a device after fabrication has been developed (Patent Literature 11, Patent Literature 12, Patent Literature 13, Patent Literature 14).

In addition, although there is an example (Patent Document 15) in which the hole mobility of the organic transistor material is improved by introducing an alkyl substituent into the anthracene oligomer, the structure does not inhibit π-π stacking by directly substituting an alkyl group in the oligoanthracene backbone with high planar continuity. Therefore, it is a technology that cannot be directly applied to organic EL devices that need to limit the planar continuity of aromatic rings in a molecule in order to control the HOMO and LUMO levels of the molecule.

Similarly, alkylhexabenzocoronene has been reported as an example of an organic transistor material in which an alkyl group is introduced directly into an aromatic ring, and it has been reported that an alkyl group disposed at an appropriate position improves the charge mobility (Patent Document 16) . On the other hand, even if an alkyl group is directly introduced into chrysene, it has not been achieved to increase carrier mobility compared to the case where a substituent of an aromatic ring is introduced (Patent Document 17). Since the preferred orientation direction of the plane of the aromatic ring of the material used for the organic transistor is perpendicular to the substrate, such a self-organizing effect by the alkyl group is undesirable for the organic EL material which transfers electric charges in the direction perpendicular to the substrate. Therefore, it cannot be predicted that the self-organization technique in an organic transistor will effectively function for charge transfer similarly even in the case of an organic EL material in which aromatic rings are difficult to approach.

Specification of Chinese Patent Application Publication No. 102790184 Japanese Patent Laid-Open No. 2009-173642 Japanese Patent Laid-Open No. 2003-146951 Japanese Patent Laid-Open No. 2005-170911 Japanese Patent Laid-Open No. 2003-277741 Japanese Patent Laid-Open No. 2006-210125 Japanese Patent Laid-Open No. 2007-134348 Japanese Patent Laid-Open No. 2003-092181 Japanese Patent Laid-Open No. 2007-109524 Japanese Patent Laid-Open No. 2011-102271 Japanese Patent Laid-Open No. Hei 5-182764 Japanese Patent Laid-Open No. 10-284248 Japanese Patent Laid-Open No. 11-40352 Japanese Patent Laid-Open No. 2000-311784 Japanese Patent Laid-Open No. 2004-107257 Japanese Patent Laid-Open No. 2006-100592 Japanese Patent Laid-Open No. 2010-118415

As described above, conventional light-emitting materials, hole-transporting materials, and electron-transporting materials in organic EL devices have a shortened device lifespan due to morphological changes such as crystallization due to heat generated from the device due to long-time energization, or electron-transporting materials. When used as a material, the light emission of the material itself is mixed and the color purity is lowered, or a material whose amorphousness is increased to suppress crystallization has a problem in the driving voltage. An object of the present invention is to provide an organic EL material capable of suppressing changes in driving voltage and luminous efficiency by reducing morphological changes due to heat.

The present inventors have found that a polycyclic aromatic compound having moderate symmetry by appropriately bonding a specific aromatic group, a heteroaromatic group, and a long-chain alkyl group is a self-organizing material having annealing resistance, and further, by using the compound as an electron transporting material, I discovered that the problem could be solved and completed the following invention.

[1] A polycyclic aromatic compound represented by the following formula (1).

(of formula 1,

Ar ¹ , Ar ² and Ar ³ are each independently a divalent aromatic group having 10 to 20 carbon atoms, and at least one hydrogen in Ar ¹ , Ar ² and Ar ³ may be substituted with a methyl group,

Ar ¹ , Ar ² and Ar ³ The total number of carbon atoms is 30 to 38,

Py ¹ and Py ² are each independently 2,5-pyridinediyl, 2,5-pyrazinediyl, 2,5-pyrimidinediyl or 2,5-pyridazinediyl, and in Py ¹ and Py ² , at least one hydrogen may be substituted with a methyl group,

Ar ¹ and the angle formed by the bonding axis between Py ¹ and Py ² bonding to 2 is 120 to 240 degrees,

R ¹ and R ² are each independently a hexyl group or a heptyl group, and any methylene group (-CH ₂ -) may be substituted with -O- or -S- in the hexyl group or heptyl group.)

[2] The polycyclic aromatic compound according to [1], wherein Ar ¹ is naphthalenediyl or anthracenediyl, and at least one hydrogen in Ar ¹ may be substituted with a methyl group.

[3] The polycyclic aromatic compound according to [1] or [2], wherein Ar ² and Ar ³ are naphthalenediyl, and at least one hydrogen in Ar ² and Ar ³ may be substituted with a methyl group.

[4] Py ¹ and Py ² are 2,5-pyridinediyl, and in Py ¹ and Py ² , at least one hydrogen may be substituted with a methyl group, the polycyclic formula according to any one of [1] to [3] aromatic compounds.

[5] The polycyclic aromatic compound according to any one of [1] to [4], wherein the total number of carbon atoms of Ar ¹ , Ar ² and Ar ³ is 30 to 34.

[6] The polycyclic aromatic compound according to any one of [1] to [5], wherein R ¹ and R ² are a hexyl group.

[7] The polycyclic aromatic compound according to the above [1], which is represented by the following formula (1-1) or (1-2).

[8] An electron transporting material containing the polycyclic aromatic compound according to any one of [1] to [7].

[9] An organic electroluminescent device comprising a pair of electrodes comprising an anode and a cathode, and an organic layer containing the compound in which the polycyclic aromatic compound according to any one of [1] to [7] is self-organized.

[10] A pair of electrodes comprising an anode and a cathode, a light emitting layer disposed between the pair of electrodes, and a polycyclic aromatic compound according to any one of [1] to [7] above, disposed between the cathode and the light emitting layer An organic electroluminescent device having an electron transport layer and/or an electron injection layer containing a structured compound.

[11] At least one of the electron transport layer and the electron injection layer is further selected from the group consisting of quinolinol-based metal complexes, pyridine derivatives, bipyridine derivatives, phenanthroline derivatives, borane derivatives, and benzimidazole derivatives. The organic electroluminescent device as described in said [10] containing.

[12] At least one of the electron transport layer and the electron injection layer may further include alkali metals, alkaline earth metals, rare earth metals, alkali metal oxides, alkali metal halides, alkaline earth metal oxides, alkaline earth metal halides, In [10] or [11] above, containing at least one selected from the group consisting of oxides of rare earth metals, halides of rare earth metals, organic complexes of alkali metals, organic complexes of alkaline earth metals and organic complexes of rare earth metals The organic electroluminescent device described.

[13] A display device comprising the organic electroluminescent element according to any one of [9] to [12] above.

[14] A lighting device comprising the organic electroluminescent element according to any one of [9] to [12] above.

[15] A method for producing an organic electroluminescent device having a pair of electrodes comprising an anode and a cathode, and an organic layer containing the compound in which the polycyclic aromatic compound according to any one of [1] to [7] is self-organized,

A method of manufacturing an organic electroluminescent device for forming an organic layer containing a self-organized polycyclic aromatic compound by depositing the organic material containing the polycyclic aromatic compound at a rate of 0.01 to 20.0 nm/sec.

The polycyclic aromatic compound of the present invention can self-organize by vapor deposition, thereby improving annealing resistance. By forming each layer of the organic EL device with the self-organized polycyclic aromatic compound, it becomes possible to reduce the change in morphology due to heat and suppress the change in voltage and luminous efficiency during driving.

The present inventors believe that the polycyclic aromatic compound of the present invention self-organizes by collision of molecules with a substrate or a molecule on a deposited substrate during deposition. Self-organization is defined as the formation of a thermodynamically stable ordered structure in which molecules in a random state are deposited as described above. It is thought that the intermolecular force between the alkyl groups and the intermolecular force between aromatic rings (especially when structural symmetry is imparted) influence this ordering, and as a result, it is possible to impart orientation to the molecule while suppressing crystallization of the polycyclic aromatic compound. I think it can be done. Energy required for ordering the molecules may use collision energy between molecules having kinetic energy during deposition and a substrate or molecules deposited on the substrate, and thermal energy from the substrate.

In particular, it is thought that the stabilization energy of the intermolecular interaction is increased by the proximity of the intermolecular aromatic rings to each other without increasing the intramolecular continuity of the aromatic rings in the polycyclic aromatic compound by self-organization by the interaction between the alkyl groups. In addition, the organic layer ordered in a stable structure does not exceed the stabilization energy of intermolecular interaction with the thermal energy of the element generated by electricity for a long time, and therefore the morphology is not affected. are doing

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing which shows the organic electroluminescent element of this embodiment.

1. Polycyclic aromatic compound represented by Formula 1

The present invention is a polycyclic aromatic compound represented by the following formula (1).

[Formula 1]

(of formula 1,

Ar ¹ , Ar ² and Ar ³ are each independently a divalent aromatic group having 10 to 20 carbon atoms, and at least one hydrogen in Ar ¹ , Ar ² and Ar ³ may be substituted with a methyl group,

Ar ¹ , Ar ² and Ar ³ The total number of carbon atoms is 30 to 38,

Py ¹ and Py ² are each independently 2,5-pyridinediyl, 2,5-pyrazinediyl, 2,5-pyrimidinediyl or 2,5-pyridazinediyl, and in Py ¹ and Py ² , at least one hydrogen may be substituted with a methyl group,

Ar ¹ and the angle formed by the bonding axis between Py ¹ and Py ² bonding to 2 is 120 to 240 degrees,

R ¹ and R ² are each independently a hexyl group or a heptyl group, and any methylene group (-CH ₂ -) may be substituted with -O- or -S- in the hexyl group or heptyl group.)

<About Ar ¹ , Ar ² and Ar ³ >

Ar ¹ , Ar ² , and Ar ³ are divalent aromatic groups having 10 to 20 carbon atoms, and although an aliphatic ring may be condensed, the structure as a whole needs to have high planarity or planarity. In the case of two or more rings, a structure in which aromatic rings are condensed is preferable, and thus the planarity of the condensed cyclic aromatic group can be further improved, so that the intermolecular force is higher and the annealing resistance can be further improved. On the other hand, in the case of a structure in which an aliphatic ring is partially condensed, the luminous efficiency can be increased in some cases. Therefore, it is preferable to design the entire structure of Ar ¹ , Ar ² and Ar ³ in consideration of their balance, Ar ¹ , The total number of carbon atoms of Ar ² and Ar ³ is 30 to 38, more preferably 30 to 34.

The divalent aromatic group has 10 to 20 carbon atoms, preferably 10 to 18 carbon atoms, more preferably 10 to 16 carbon atoms, still more preferably 10 to 14 carbon atoms.

Examples of the divalent aromatic group include naphthalenediyl, tetrahydronaphthalenediyl, azulenediyl, acenaphthenediyl, acenaphthylenediyl, anthracenediyl, dihydroanthraceenediyl, tetrahydroanthracenediyl, phenanthrenediyl, fluorenediyl, dihydrophenanthrenedi yl, fluoranthenediyl, chrysenediyl, pyrenediyl, benzofluorenediyl, triphenylenediyl, naphthacenediyl, benzo[a]anthracene, benzo[a]phenanthrene, and benzo[c]phenanthrene are preferable. , naphthalenediyl, anthracenediyl, phenanthrenediyl, fluorenediyl, and dihydrophenanthrenediyl are more preferable.

Naphthalenediyl is preferably 1,4-, 1,5-, 2,6- or 2,7-naphthalenediyl, particularly preferably 1,4-, 2,6- or 2,7-naphthalenediyl. When a methyl group is substituted, 1-6 pieces are preferable, as for the number of substituents, 1-2 pieces are more preferable, and two pieces are especially preferable. As the methyl group-substituted form, a methyl group is preferably substituted at a position that increases the dihedral angle with an adjacent heteroaromatic ring, 1-methylnaphthalene-2,6-diyl, 3-methylnaphthalene-2,6-diyl , 1,3-dimethylnaphthalene-2,6-diyl, 2-methylnaphthalene-1,4-diyl, 2,8-dimethylnaphthalene-1,4-diyl, and the like are preferable.

1,4-, 1,5-, 2,6-, 2,7- or 9,10-anthracenediyl is preferred, 2,6- or 9,10-anthracenediyl is particularly preferred. When a methyl group is substituted, 1-4 pieces are preferable, as for the number of substituents, 1-2 pieces are more preferable, and two pieces are especially preferable. As the form substituted with a methyl group, a case in which a methyl group is substituted at a position that increases the dihedral angle with an adjacent heteroaromatic ring is preferable, and 1-methyl-9,10-anthracenediyl, 1,4-dimethyl-9,10- Anthracenediyl, 1,5-dimethyl-9,10-anthracenediyl, 1,8-dimethyl-9,10-anthracenediyl, and the like are preferable.

Phenanthrenediyl is preferably 2,6-, 2,7- or 3,9-phenanthrenediyl, especially 2,7-phenanthrenediyl. When a methyl group is substituted, the number of substituents is preferably 1 to 4, more preferably 1 to 2, particularly preferably 2, and the form substituted with a methyl group is 1,8-dimethyl-2,7-phenanthrenediyl; 3,6-dimethyl-2,7-phenanthrenediyl is preferred.

The fluorenediyl is preferably 2,7-fluorenediyl, and when a methyl group is substituted, the number of substituents is preferably 1 to 4, more preferably 1 to 2, particularly preferably 2, substituted with 2 methyl groups 9,9-dimethylfluorene-2,7-diyl is preferred in the form of ,9,9-tetramethylfluorene-2,7-diyl is preferred.

The dihydrophenanthrenediyl is preferably 9,10-dihydrophenanthrene-2,7-diyl. When a methyl group is substituted, the number of substituents is preferably 1 to 4, more preferably 1 to 2, particularly preferably 2, and as a form substituted with two methyl groups, 1,8-dimethyl-9,10-dihydro Phenanthrene, 3,6-dimethyl-9,10-dihydrophenanthrene is preferred.

The molecular structure is preferably highly symmetrical, and Ar ² and Ar ³ are more preferably the same aromatic group bonded at the same substitution position, particularly preferably 2,6-naphthalenediyl.

<About Py ¹ and Py ² in Formula 1>

Py ¹ and Py ² in formula (1) are each independently 2,5-pyridinediyl, 2,5-pyrazinediyl, 2,5-pyrimidinediyl or 2,5-pyridazinediyl, and 2,5-pyridinediyl Especially preferred. Further, it may be substituted with one or more methyl groups, and examples of the methyl group substituted form include 3-methyl-2,5-pyridinediyl, 4-methyl-2,5-pyridinediyl, 6-methyl-2,5-pyridinediyl, 3 ,4-dimethyl-2,5-pyridinediyl, 3,6-dimethyl-2,5-pyridinediyl, 4,6-dimethyl-2,5-pyridinediyl or 3,4,6-trimethyl-2,5- Pyridindiyl is preferred.

<Angle formed by the bonding axis of Ar ¹ and Py ¹ and Py ² >

The angle formed by the bonding axis between Py ¹ and Py ² bonding to Ar ¹ is 120 to 240 degrees, preferably 140 to 220 degrees, more preferably 160 to 200 degrees, particularly preferably 180 degrees. . If the angle formed by the two bonding axes is 120 to 240 degrees, the disruption of molecular orientation can be reduced, and a reduction in morphological change due to heat can be expected.

<About R ¹ and R ² >

R< ¹ > and R< ² > are a hexyl group or a heptyl group, straight chain is preferable and it is more preferable that they are the same group.

In R ¹ and R ² , any methylene group (-CH ₂ -) may be substituted with -O- or -S-, and as a group formed as a result of substitution, hexyloxy, heptyloxy, hexylthio, heptylthio is preferable

<Self-organization and structure of polycyclic aromatic compound>

The polycyclic aromatic compound of the present invention has an appropriate number of, suitable chain length, straight-chain alkyl groups disposed at appropriate positions in the molecule, and symmetrically disposed aromatic groups of an appropriate number and appropriate size at appropriate positions in the molecule, and By symmetrically disposing a plurality of heteroatoms, self-organization with high stability becomes possible. Suitable for self-organization at an appropriate position or number at which an alkyl group or aromatic group (hereinafter, including a heteroaromatic group containing a heteroatom) is disposed, and at a distance at which the interaction between the alkyl groups or aromatic ring moieties of the molecule effectively acts It is a position or a number, and it changes with the structure of a polycyclic aromatic compound. An alkyl group or aromatic group substituted in an inappropriate position, an alkyl group or aromatic group having an excessive number of alkyl groups or aromatic groups limits the direction of interaction between alkyl groups or aromatic rings, weakens the interaction between alkyl groups or aromatic rings, or causes an unbalanced interaction The action becomes a factor that reduces the stability of the organization. In addition, the appropriate chain length of the alkyl group means that when the alkyl group is too short, self-organization is difficult to occur, and when the alkyl group is too long, the self-organization effect is weakened by folding of the alkyl group, that is, the interaction between the aromatic ring parts of the molecule is weakened. The chain length between them is an appropriate chain length. An aromatic group of an appropriate size is essential for stable self-organization, and it is necessary to withstand the thermal energy applied after organization. If the number of large aromatic groups increases, the intermolecular interaction becomes excessively large, and the sublimation energy exceeds the thermal decomposition energy, causing material decomposition during deposition. Properly symmetrical arrangement of the aromatic group in the molecule is important for forming a stable structure that is difficult to change by heat, and symmetrical arrangement of the heteroatom in the molecule reduces the dipole moment of the molecule and drives it by dielectric polarization. Contributes to suppression of voltage rise.

<Self-organization and deposition conditions>

The energy required for self-organization is procured by collisions of molecules during deposition or thermal energy applied during device fabrication. Molecular collision means that molecules protruding from an evaporation source collide with a substrate or molecules deposited on the substrate. Kinetic energy of flying molecules is converted into thermal energy by collision, and thermal energy minus heat radiation is used for self-organization. Therefore, the faster the film formation rate, the more heat is accumulated and self-organization is promoted. In addition, as the number of carbon atoms in the material molecules increases, the latent heat of sublimation increases, and the thermal energy of the molecules protruding from the evaporation source also increases, so that self-organization is promoted. However, the latent heat of sublimation must not exceed the thermal decomposition energy of the molecule, so there is an upper limit to the number of carbon atoms in the material molecule. The film-forming rate is not particularly limited as it differs depending on the structure of the material molecule, the length of the alkyl chain, and the like, but ranges from 0.01 nm/sec to 20.0 nm/sec. The degree of self-organization can be increased by setting the film-forming rate to preferably 0.2 nm/sec or more, more preferably 0.5 nm/sec or more, and still more preferably 1 nm/sec or more.

When the degree of self-organization is insufficient due to the inappropriate number or arrangement of alkyl groups, aromatic groups, and heteroaromatic groups, the degree of self-organization may be increased even by heating after device fabrication. Since it means that the morphology can be changed when it is increased, it is preferable to increase the degree of self-organization during the deposition as it may cause a voltage increase or a decrease in luminous efficiency during driving.

Specific examples of the polycyclic aromatic compound represented by the formula (1) are shown below, but it is not limited to the compounds represented by the formulas (1-1) to (1-336) exemplified below.

2. Synthesis method of the compound represented by formula (1)

The polycyclic aromatic compound represented by the formula (1) is prepared by a known method using an aryl halide (or aryl triflate) and an aryl boronic acid (or an aryl metal compound or a boronic acid ester) as starting materials, followed by Suzuki-Miyaura coupling, It can be synthesized by appropriately combining a Kumada/Tamao/Koryu coupling, a Negishi coupling, a Sonogashira/Hagiwara coupling, a halogenation reaction, a deprotection reaction, a triflation reaction, or a boron oxidation reaction.

A representative synthesis method for a compound in which Ar ¹ is a 9,10-anthracenediyl group, Ar ² and Ar ³ is a 2,6-naphthalenediyl group, and R ¹ and R ² is a hexyl group is shown below. The same can be explained for the group. Moreover, in each process, it is possible to carry out by substituting an aryl halide and an aryl boronic acid, and it is also possible to carry out by changing the leaving group in a coupling reaction with another halogen or a triflate. Changing the protecting group to another protecting group or not using a protecting group can be selected. It is also possible to change the alcohol side of the boronic acid ester to another alcohol.

Specific examples of the palladium catalyst used in the coupling reaction include tetrakis(triphenylphosphine)palladium(0):Pd(PPh ₃ ) ₄ , bis(triphenylphosphine)palladium(II)dichloride:PdCl ₂ (PPh ₃ ) ) ₂ , palladium (II) acetate: Pd(OAc) ₂ , tris (dibenzylideneacetone) palladium (0): Pd ₂ (dba) ₃ , tris (dibenzylidene acetone) palladium (0) chloroform complex: Pd ₂ (dba) ₃ CHCl ₃ , Bis(dibenzylideneacetone)palladium(0): Pd(dba) ₂ , Bis(trit-butylphosphino)palladium(0):Pd(t-Bu ₃ P) ₂ , [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium( _II ):Pd(dppf)Cl2,[1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) Dichloromethane complex (1:1): Pd(dppf)Cl ₂ CH ₂ Cl ₂ , PdCl ₂ ｛P(t-Bu) ₂ -(p-NMe ₂ -Ph)｝ ₂ :(A- ^ta Phos) ₂ PdCl ₂ , palladium bis(dibenzylidene), [1,3-bis(diphenylphosphino)propane]nickel( _II )dichloride, PdCl2[P(t-Bu) ₂ -(p-NMe ₂ -Ph) )] ₂ : (A- ^ta Phos) ₂ PdCl ₂ (Pd-132: trademark; manufactured by Johnson Matty Corporation) is mentioned.

Moreover, in order to accelerate|stimulate a coupling reaction, you may add a phosphine compound to these palladium compounds as needed. Specific examples of the phosphine compound include tri(t-butyl)phosphine, tricyclohexylphosphine, 1-(N,N-dimethylaminomethyl)-2-(dit-butylphosphino)ferrocene, 1-(N ,N-dibutylaminomethyl)-2-(dit-butylphosphino)ferrocene, 1-(methoxymethyl)-2-(dit-butylphosphino)ferrocene, 1,1'-bis(dit -Butylphosphino)ferrocene, 2,2'-bis(di-t-butylphosphino)-1,1'-binaphthyl, 2-methoxy-2'-(dit-butylphosphino)-1, 1'-binaphthyl or 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl.

Specific examples of the base used in the coupling reaction include sodium carbonate, potassium carbonate, cesium carbonate, sodium hydrogen carbonate, lithium hydroxide, sodium hydroxide, potassium hydroxide, barium hydroxide, sodium methoxide, sodium ethoxide, sodium t-butoxide, sodium t-pentoxide, sodium acetate, potassium acetate, tripotassium phosphate, or potassium fluoride.

Specific examples of the solvent used in the coupling reaction include benzene, toluene, xylene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, anisole, acetonitrile, dimethyl sulfoxide, N,N-dimethylform Amide, N,N-dimethylacetamide, tetrahydrofuran, 2-methyltetrahydrofuran, diethyl ether, t-butylmethyl ether, 1,4-dioxane, cyclopentylmethyl ether, water, methanol, ethanol, propanol or t-butyl alcohol. These solvents can be selected suitably, and may be used independently or may be used as a mixed solvent.

As a brominating agent for an aromatic ring or a heteroaromatic ring, N-bromosuccinimide or bromine is used. As a solvent for the bromination reaction, N,N-dimethylformamide, acetonitrile, dichloromethane, chloroform, carbon tetrachloride, or a mixed solvent thereof is used.

As the protecting group of the hydroxyl group on the aromatic ring or the heteroaromatic ring, alkyl ether, benzyl ether, silyl ether or ester can be appropriately used. The alkyl group of the alkyl ether may be linear or branched, and an alkyl group having 1 to 12 carbon atoms is preferable, and methyl or ethyl is more preferable. However, there are cases where octyl, decyl or dodecyl is preferable in order to increase the solubility of the substrate.

As a deprotecting agent, a thing suitable for the protecting group used can be used suitably. As the alkyl ether deprotecting agent, pyridine hydrochloride, boron tribromide, decanethiol/potassium t-butoxide, aluminum iodide, protonic acid/ionic liquid, iodotrimethylsilane, lithium chloride/dimethylformamide, and the like can be used.

When the following step is a reaction using an organometallic reagent, it is also possible to use the organometallic reagent in an amount corresponding to the hydroxyl group in addition to the amount required for the intended reaction without using a protecting group. In addition, when the next step is Suzuki-Miyaura coupling, it is not necessary to protect the hydroxyl group, but it is also possible to use a protecting group for the purpose of increasing the solubility of the substrate.

In addition, the polycyclic aromatic compound of the present invention includes those in which at least a part of hydrogen atoms are substituted with deuterium. Such derivatives can be synthesized in the same manner as above by using a raw material in which the desired site is deuterated.

3. Organic electroluminescent device

The polycyclic aromatic compound of the present invention can be used, for example, as a material for an organic electroluminescent device. Below, the organic EL element of this embodiment is demonstrated in detail based on drawing. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing which shows the organic electroluminescent element of this embodiment.

<Structure of organic electroluminescent device>

The organic electroluminescent device 100 shown in FIG. 1 is a substrate 101 , an anode 102 provided on the substrate 101 , a hole injection layer 103 provided on the anode 102 , and a hole injection layer 103 on the The hole transport layer 104 provided, the light emitting layer 105 provided over the hole transport layer 104, the electron transport layer 106 provided over the light emitting layer 105, the electron injection layer 107 provided over the electron transport layer 106, and an electron injection layer ( 107) has a cathode 108 installed thereon.

In addition, the organic electroluminescent device 100 is manufactured by reversing the manufacturing order, for example, the substrate 101, the cathode 108 provided on the substrate 101, the electron injection layer 107 provided on the cathode 108, and the electron injection The electron transport layer 106 provided on the layer 107, the light emitting layer 105 provided on the electron transport layer 106, the hole transport layer 104 provided on the light emitting layer 105, the hole injection layer 103 provided on the hole transport layer 104, and the anode 102 provided on the hole injection layer 103 .

All of the above layers are not indispensable, and the minimum structural unit is made up of an anode 102, a light emitting layer 105 and a cathode 108, and a hole injection layer 103, a hole transport layer 104, an electron transport layer ( 106) and the electron injection layer 107 are arbitrarily provided layers. In addition, each of said layers may consist of a single layer, respectively, and may consist of multiple layers.

As an aspect of the layer constituting the organic electroluminescent element, in addition to the configuration aspect of "substrate / anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode" described above, "substrate / anode / hole transport layer / light emitting layer" /electron transport layer/electron injection layer/cathode", "substrate/anode/hole injection layer/light emitting layer/electron transport layer/electron injection layer/cathode", "substrate/anode/hole injection layer/hole transport layer/light emitting layer/electron injection layer/ Cathode", "substrate / anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / cathode", "substrate / anode / light emitting layer / electron transport layer / electron injection layer / cathode", "substrate / anode / hole transport layer / light emitting layer / "Electron injection layer/cathode", "Substrate/anode/hole transport layer/light-emitting layer/electron transport layer/cathode", "substrate/anode/hole injection layer/light-emitting layer/electron injection layer/cathode", "substrate/anode/hole injection layer/ Light-emitting layer/electron-transporting layer/cathode", "substrate/anode/light-emitting layer/electron-transporting layer/cathode", and "substrate/anode/light-emitting layer/electron injection layer/cathode" may be configured.

<Substrate in organic electroluminescent element>

The substrate 101 serves as a support for the organic electroluminescent device 100 , and usually quartz, glass, metal, plastic, or the like is used. The substrate 101 is formed in a plate shape, a film shape, or a sheet shape depending on the purpose, and for example, a glass plate, a metal plate, a metal foil, a plastic film, a plastic sheet, etc. are used. Among them, glass plates and plates made of transparent synthetic resins such as polyester, polymethacrylate, polycarbonate and polysulfone are preferable. In the case of a glass substrate, soda-lime glass, alkali-free glass, etc. are used, and since the thickness may be sufficient to maintain mechanical strength, it may be, for example, 0.2 mm or more. The upper limit of the thickness is, for example, 2 mm or less, preferably 1 mm or less. As for the material of the glass, since it is preferable that there are few ions eluted from the glass, the alkali _- free glass is preferable. In addition, in order to improve gas barrier properties, a gas barrier film such as a dense silicon oxide film may be provided on at least one side of the substrate 101. In particular, when a synthetic resin plate, film or sheet with low gas barrier properties is used as the substrate 101 It is preferable to provide a gas barrier film.

<Anode in organic electroluminescent element>

The anode 102 serves to inject holes into the light emitting layer 105 . In addition, when the hole injection layer 103 and/or the hole transport layer 104 is provided between the anode 102 and the light emitting layer 105 , holes are injected into the light emitting layer 105 through these.

Examples of the material for forming the anode 102 include inorganic compounds and organic compounds. Examples of the inorganic compound include metals (aluminum, gold, silver, nickel, palladium, chromium, etc.), metal oxides (indium oxide, tin oxide, indium-tin oxide (ITO), indium-zinc oxide (IZO), etc.) , metal halide (copper iodide, etc.), copper sulfide, carbon black, ITO glass, nesa glass, etc. are mentioned. Examples of the organic compound include polythiophene such as poly(3-methylthiophene), and conductive polymers such as polypyrrole and polyaniline. In addition, it can be used by selecting suitably from the materials used as an anode of an organic electroluminescent element.

The resistance of the transparent electrode is not limited as long as sufficient current can be supplied for light emission of the light emitting device, but it is preferable that the resistance is low from the viewpoint of power consumption of the light emitting device. For example, an ITO substrate of 300 Ω/square or less functions as an element electrode, but now it is possible to supply a substrate of about 10 Ω/square, for example, 100 to 5 Ω/square, preferably 50 to 5 Ω/square. It is particularly preferable to use a low-resistance product of The thickness of ITO can be arbitrarily selected according to the resistance value, but it is often used between 50 and 300 nm.

<Hole injection layer and hole transport layer in organic electroluminescent element>

The hole injection layer 103 serves to efficiently inject holes moved from the anode 102 into the light emitting layer 105 or the hole transport layer 104 . The hole transport layer 104 serves to efficiently transport holes injected from the anode 102 or holes injected from the anode 102 via the hole injection layer 103 to the emission layer 105 . Each of the hole injection layer 103 and the hole transport layer 104 is formed by laminating one or two or more types of hole injection/transport materials, or a mixture of a hole injection/transport material and a polymer binder. Further, an inorganic salt such as iron (III) chloride may be added to the hole injection/transport material to form a layer.

As the hole injection/transport material, it is necessary to efficiently inject and transport holes from the positive electrode between the electrodes to which the electric field is applied, and it is desirable to have high hole injection efficiency and to efficiently transport the injected holes. For this purpose, it is preferable that the ionization potential is small, the hole mobility is large, the stability is excellent, and the material that becomes a trap is difficult to generate during manufacture and use.

As a material for forming the hole injection layer 103 and the hole transport layer 104 , the polycyclic aromatic compound represented by Chemical Formula 1 may be used. In addition, in the photoconductive material, any compound can be selected and used as a charge transport material for holes from known compounds conventionally used, p-type semiconductors, hole injection layers and hole transport layers of organic electroluminescent devices.

Specific examples thereof include carbazole derivatives (N-phenylcarbazole, polyvinylcarbazole, etc.), biscarbazole derivatives such as bis(N-arylcarbazole) or bis(N-alkylcarbazole), and triarylamine derivatives (Polymer having aromatic tertiary amino in the main chain or side chain, 1,1-bis(4-di-p-tolylaminophenyl)cyclohexane, N,N'-diphenyl-N,N'-di(3- methylphenyl)-4,4'-diaminobiphenyl, N,N'-diphenyl-N,N'-dinaphthyl-4,4'-diaminobiphenyl, N,N'-diphenyl-N, N'-di(3-methylphenyl)-4,4'-diphenyl-1,1'-diamine, N,N'-dinaphthyl-N,N'-diphenyl-4,4'-diphenyl- 1,1'-diamine, N ^{4 ,} N 4'-diphenyl-N ^{4 ,} N 4'-bis(9-phenyl-9H-carbazol-3-yl)-[1,1'-biphenyl]- 4,4'-diamine, N ⁴ ,N ⁴ ,N ^{4 '} ,N 4'-tetra[1,1'-biphenyl]-4-yl)-[1,1'-biphenyl]-4,4 Triphenylamine derivatives such as '-diamine, 4,4',4"-tris(3-methylphenyl(phenyl)amino)triphenylamine, starburst amine derivatives, etc.), stilbene derivatives, phthalocyanine derivatives (metal-free, copper phthalocyanine, etc.), pyrazoline derivatives, hydrazone compounds, benzofuran derivatives and thiophene derivatives, oxadiazole derivatives, quinoxaline derivatives (for example, 1,4,5,8,9,12-hexaazatriphenylene- 2,3,6,7,10,11-hexacarbonitrile, etc.), heterocyclic compounds such as porphyrin derivatives, polysilane, etc. In the polymer system, polycarbonate or styrene derivatives having the above monomers in the side chain, polyvinylcarbazole and polysilane, etc., but is not particularly limited as long as it is a compound capable of injecting holes from an anode and transporting holes by forming a thin film necessary for manufacturing a light emitting device.

It is also known that the conductivity of an organic semiconductor is strongly influenced by its doping. Such an organic semiconductor matrix material is composed of a compound having a good electron donating property or a good electron accepting compound. Strong electron acceptors such as tetracyanoquinonedimethane (TCNQ) or 2,3,5,6-tetrafluorotetracyano-1,4-benzoquinonedimethane (F4TCNQ) are known for doping of electron-donating materials. (see, for example, M. Pfeiffer, A. Beyer, T. Fritz, K. Leo, Appl. Phys. Lett., 73(22), 3202-3204 (1998) and J. Blochwitz, M. Pheiffer, T. Fritz, K. Leo, Appl. Phys. Lett., 73(6), 729-731 (1998)). These generate so-called holes by an electron transfer process in an electron-donating base material (hole transport material). The conductivity of the base material changes significantly depending on the number and mobility of holes. As a matrix material having hole transport properties, for example, benzidine derivatives (TPD, etc.) or starburst amine derivatives (TDATA, etc.) or specific metal phthalocyanines (especially zinc phthalocyanine (ZnPc) etc.) are known (Japanese Patent Laid-Open No. 2005- Publication No. 167175).

<Light emitting layer in organic electroluminescent element>

The light emitting layer 105 emits light by recombination of holes injected from the anode 102 and electrons injected from the cathode 108 between the electrodes to which the electric field is applied. The material for forming the light emitting layer 105 may be a compound that emits light by being excited by recombination of holes and electrons (a luminescent compound). it is preferable In the present invention, the polycyclic aromatic compound represented by Formula 1 may be used as a material for the light emitting layer.

A single layer may be sufficient as it or it may consist of multiple layers, and a light emitting layer is formed of the material (host material, dopant material) for light emitting layer, respectively. The number of each of a host material and a dopant material may be one, or a several combination may be sufficient as it. The dopant material may be contained in the whole host material, or may be contained partially. Although it can form by the method of co-evaporation with a host material as a doping method, you may vapor-deposit simultaneously after mixing with a host material beforehand.

The amount of the host material used varies depending on the type of the host material, and may be determined according to the characteristics of the host material. The amount of the host material used is preferably 50 to 99.999% by weight of the entire material for the light emitting layer, more preferably 80 to 99.95% by weight, and still more preferably 90 to 99.9% by weight. The polycyclic aromatic compound represented by the above formula (1) can also be used as a host material.

The amount of the dopant material used varies depending on the type of the dopant material and may be determined according to the characteristics of the dopant material. The reference amount of the dopant material is preferably 0.001 to 50% by weight, more preferably 0.05 to 20% by weight, and still more preferably 0.1 to 10% by weight of the total weight of the light emitting layer material. If it is in the said range, for example, it is preferable at the point that a density|concentration quenching phenomenon can be prevented. The polycyclic aromatic compound represented by the above formula (1) can also be used as a dopant material.

As a host material that can be used in combination with the polycyclic aromatic compound represented by the formula (1), condensed ring derivatives such as anthracene and pyrene, bisstyryl derivatives such as bisstyrylanthracene derivatives and distyrylbenzene derivatives, which have been previously known as light emitters; A tetraphenylbutadiene derivative, a cyclopentadiene derivative, a fluorene derivative, a benzofluorene derivative, etc. are mentioned.

In addition, the dopant material that can be used in combination with the polycyclic aromatic compound represented by the above formula (1) is not particularly limited, and a known compound can be used, and various materials can be selected according to the desired emission color. Specifically, for example, condensed ring derivatives such as phenanthrene, anthracene, pyrene, tetracene, pentacene, perylene, naphthopyrene, dibenzopyrene, rubrene and chrysene, benzoxazole derivatives, and benzothiazole derivatives , benzoimidazole derivatives, benzotriazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, imidazole derivatives, thiadiazole derivatives, triazole derivatives, pyrazoline derivatives, stilbene derivatives, thiophene derivatives, tetra Bisstyryl derivatives such as phenylbutadiene derivatives, cyclopentadiene derivatives, bisstyrylanthracene derivatives and distyrylbenzene derivatives (Japanese Patent Application Laid-Open No. Hei 1-245087), bisstyryl arylene derivatives (Japanese Patent Laid-Open No. Hei Hei) 2-247278), diazaindacene derivatives, furan derivatives, benzofuran derivatives, phenylisobenzofuran, dimethylisobenzofuran, di(2-methylphenyl)isobenzofuran, di(2-trifluoromethylphenyl) Isobenzofuran derivatives such as isobenzofuran and phenylisobenzofuran, dibenzofuran derivatives, 7-dialkylaminocoumarin derivatives, 7-piperidinocoumarin derivatives, 7-hydroxycoumarin derivatives, 7-methoxycoumarin derivatives; Coumarin derivatives such as 7-acetoxycoumarin derivative, 3-benzothiazolylcoumarin derivative, 3-benzoimidazolylcoumarin derivative, 3-benzooxazolylcoumarin derivative, dicyanomethylenepyran derivative, dicyanomethylenethiopyran derivative, poly Methine derivatives, cyanine derivatives, oxobenzoanthracene derivatives, xanthene derivatives, rhodamine derivatives, fluorescein derivatives, pyrylium derivatives, carbostyryl derivatives, acridine derivatives, oxazine derivatives, phenylene oxide derivatives, quinacridone Derivatives, quinazoline derivatives, pyrrolopyridine derivatives, furopyridine derivatives, 1,2,5-thiadiazolopyrene derivatives, pyromethene derivatives, pelinone derivatives, pyrrolopyrrole derivatives, squarylium derivatives, biolanthrone derivatives, and phenazine derivatives, acridone derivatives, deazaflavin derivatives, fluorene derivatives and benzofluorene derivatives.

When exemplified by color light, the blue to blue-green dopant materials include aromatic hydrocarbon compounds such as naphthalene, anthracene, phenanthrene, pyrene, triphenylene, perylene, fluorene, indene, chrysene, and derivatives thereof, furan, pyrrole, and thiophene. , sirol, 9-silafluorene, 9,9'-spirobicillafluorene, benzothiophene, benzofuran, indole, dibenzothiophene, dibenzofuran, imidazopyridine, phenanthroline, pyrazine, naphthyridine Aromatic heterocyclic compounds such as , quinoxaline, pyrrolopyridine, thioxanthene, and derivatives thereof, distyrylbenzene derivatives, tetraphenylbutadiene derivatives, stilbene derivatives, aldazine derivatives, coumarin derivatives, imidazole, thiazole, thiadia Azole derivatives such as sol, carbazole, oxazole, oxadiazole and triazole, and metal complexes thereof and N,N'-diphenyl-N,N'-di(3-methylphenyl)-4,4'-diphenyl and aromatic amine derivatives typified by -1,1'-diamine.

In addition, as green-yellow dopant materials, coumarin derivatives, phthalimide derivatives, naphthalimide derivatives, perinone derivatives, pyrrolopyrrole derivatives, cyclopentadiene derivatives, acridone derivatives, quinacridone derivatives, rubrene, etc. naphthacene derivatives, and the like. Also suitable examples are compounds in which a substituent capable of lengthening the wavelength such as aryl, heteroaryl, arylvinyl, amino, and cyano is introduced into the compounds exemplified as the above blue to blue-green dopant materials. can be heard

In addition, as the orange-red dopant material, a naphthalimide derivative such as bis(diisopropylphenyl)perylenetetracarboxylic acid imide, a perinone derivative, or an Eu complex containing acetylacetone or benzoylacetone and phenanthroline as a ligand rare earth complexes such as 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran and its analogues, and metal phthalocyanine derivatives such as magnesium phthalocyanine and aluminum chlorophthalocyanine , rhodamine compounds, deazaflavin derivatives, coumarin derivatives, quinacridone derivatives, phenoxazine derivatives, oxazine derivatives, quinazoline derivatives, pyrrolopyridine derivatives, squarylium derivatives, biolanthrone derivatives, phenazine derivatives, and phenoxazone derivatives and thiadiazolopyrene derivatives. Also, the compounds exemplified as the above blue-blue-green and green-yellow dopant materials can have long wavelengths such as aryl, heteroaryl, arylvinyl, amino, and cyano. A compound having a substituent introduced thereto is also exemplified as a suitable example.

In addition, as a dopant, it can select and use suitably the compound etc. which were described in the chemical industry June 2004 issue, page 13 and the references published therein.

Among the dopant materials described above, amines having a stilbene structure, perylene derivatives, borane derivatives, aromatic amine derivatives, coumarin derivatives, pyran derivatives or pyrene derivatives are particularly preferable.

An amine having a stilbene structure is, for example, represented by the following formula.

In the above formula, Ar ¹¹ is an m-valent group derived from aryl having 6 to 30 carbon atoms, Ar ¹² and Ar ¹³ are each independently aryl having 6 to 30 carbon atoms, and at least one of Ar ¹¹ to Ar ¹³ has a stilbene structure. and Ar ¹¹ to Ar ¹³ may be substituted with aryl, heteroaryl, alkyl, trisubstituted silyl (silyl trisubstituted with aryl and/or alkyl) or cyano, and m is an integer of 1 to 4.

The amine having a stilbene structure is more preferably diaminostilbene represented by the following formula.

In the formula, Ar ¹² and Ar ¹³ are each independently aryl having 6 to 30 carbon atoms, and Ar ¹² and Ar ¹³ are aryl, heteroaryl, alkyl, trisubstituted silyl (silyl trisubstituted with aryl and/or alkyl) or cya. It may be substituted with a furnace.

Specific examples of aryl having 6 to 30 carbon atoms include phenyl, naphthyl, acenaphthylenyl, fluorenyl, phenalenyl, phenanthrenyl, anthryl, fluoranthenyl, triphenylenyl, pyrenyl, chrysenyl, naphthacenyl , perylenyl, stilbenyl, distyrylphenyl, distyrylbiphenylyl, distyrylfluorenyl, and the like.

Specific examples of the amine having a stilbene structure include N,N,N',N'-tetra(4-biphenylyl)-4,4'-diaminostilbene, N,N,N',N'-tetra (1-naphthyl)-4,4'-diaminostilbene, N,N,N',N'-tetra(2-naphthyl)-4,4'-diaminostilbene, N,N'- Di(2-naphthyl)-N,N'-diphenyl-4,4'-diaminostilbene, N,N'-di(9-phenanthryl)-N,N'-diphenyl-4,4 '-Diaminostilbene, 4,4'-bis[4"-bis(diphenylamino)styryl]-biphenyl, 1,4-bis[4'-bis(diphenylamino)styryl]-benzene , 2,7-bis[4'-bis(diphenylamino)styryl]-9,9-dimethylfluorene, 4,4'-bis(9-ethyl-3-carbazovinylene)-biphenyl, 4,4'-bis(9-phenyl-3-carbazovinylene)-biphenyl etc. are mentioned.

Moreover, you may use the amine which has a stilbene structure described in Unexamined-Japanese-Patent No. 2003-347056, Unexamined-Japanese-Patent No. 2001-307884, etc.

Examples of the perylene derivative include 3,10-bis(2,6-dimethylphenyl)perylene, 3,10-bis(2,4,6-trimethylphenyl)perylene, 3,10-diphenylperylene, 3,4-diphenylperylene, 2,5,8,11-tetra-t-butylperylene, 3,4,9,10-tetraphenylperylene, 3-(1'-pyrenyl)-8, 11-di(t-butyl)perylene, 3-(9'-anthryl)-8,11-di(t-butyl)perylene, 3,3'-bis(8,11-di(t-butyl) ) perylenyl) and the like.

In addition, Japanese Patent Laid-Open No. 11-97178, Japanese Patent Laid-Open No. 2000-133457, Japanese Patent Laid-Open No. 2000-26324, Japanese Patent Laid-Open No. 2001-267079, Japanese Patent Laid-Open No. 2001-267078, Japanese Unexamined Patent Publication No. 2001-267076, Japanese Unexamined Patent Publication No. 2000-34234, Japanese Unexamined Patent Publication No. 2001-267075, and Japanese Unexamined Patent Application Publication No. 2001-217077 You may use the perylene derivatives described in others.

Examples of the borane derivative include 1,8-diphenyl-10-(dimethylboryl)anthracene, 9-phenyl-10-(dimethylboryl)anthracene, and 4-(9'-anthryl)dimethylboryl. Naphthalene, 4-(10'-phenyl-9'-anthryl) dimesitylborylnaphthalene, 9-(dimethylboryl)anthracene, 9-(4'-biphenylyl)-10-(dimethylboryl) ) anthracene and 9-(4'-(N-carbazolyl)phenyl)-10-(dimethylboryl)anthracene.

Moreover, you may use the borane derivative described in the international publication 2000/40586 pamphlet etc.

The aromatic amine derivative is represented by the following formula, for example.

In the formula, Ar ¹⁴ is an n-valent group derived from aryl having 6 to 30 carbon atoms, Ar ¹⁵ and Ar ¹⁶ are each independently aryl having 6 to 30 carbon atoms, Ar ¹⁴ to Ar ¹⁶ are aryl, heteroaryl, alkyl, It may be substituted with trisubstituted silyl (silyl trisubstituted with aryl and/or alkyl) or cyano, and n is an integer of 1-4.

In particular, Ar ¹⁴ is a divalent group derived from anthracene, chrysene, fluorene, benzofluorene or pyrene, Ar ¹⁵ and Ar ¹⁶ are each independently aryl having 6 to 30 carbon atoms, Ar ¹⁴ to Ar ¹⁶ are aryl; An aromatic amine derivative which may be substituted with heteroaryl, alkyl, trisubstituted silyl (silyl trisubstituted with aryl and/or alkyl) or cyano and n is 2 is more preferable.

Specific examples of aryl having 6 to 30 carbon atoms include phenyl, naphthyl, acenaphthylenyl, fluorenyl, phenalenyl, phenanthrenyl, anthryl, fluoranthenyl, triphenylenyl, pyrenyl, chrysenyl, naphthacenyl , perylenyl, pentacenyl, and the like.

As an aromatic amine derivative, as a chrysene type, N,N,N',N'-tetraphenylchrysene-6,12-diamine, N,N,N',N'-tetra(p-tolyl)chrysene- 6,12-diamine, N,N,N',N'-tetra(m-tolyl)chrysene-6,12-diamine, N,N,N',N'-tetrakis(4-isopropylphenyl) Chrysene-6,12-diamine, N,N,N',N'-tetra(naphthalen-2-yl)chrysene-6,12-diamine, N,N'-diphenyl-N,N'-di (p-tolyl) chrysene-6,12-diamine, N,N'-diphenyl-N,N'-bis(4-ethylphenyl)chrysene-6,12-diamine, N,N'-diphenyl -N,N'-bis(4-ethylphenyl)chrysene-6,12-diamine, N,N'-diphenyl-N,N'-bis(4-isopropylphenyl)chrysene-6,12- Diamine, N,N'-diphenyl-N,N'-bis(4-t-butylphenyl)chrysene-6,12-diamine, N,N'-bis-(4-isopropylphenyl)-N, N'-di(p-tolyl)chrysene-6,12-diamine etc. are mentioned.

Moreover, as a pyrene type, for example, N,N,N',N'-tetraphenylpyrene-1,6-diamine, N,N,N',N'-tetra(p-tolyl)pyrene-1,6-diamine , N,N,N',N'-tetra(m-tolyl)pyrene-1,6-diamine, N,N,N',N'-tetrakis(4-isopropylphenyl)pyrene-1,6- Diamine, N,N,N',N'-tetrakis(3,4-dimethylphenyl)pyrene-1,6-diamine, N,N'-diphenyl-N,N'-di(p-tolyl)pyrene -1,6-diamine, N,N'-diphenyl-N,N'-bis(4-ethylphenyl)pyrene-1,6-diamine, N,N'-diphenyl-N,N'-bis( 4-ethylphenyl)pyrene-1,6-diamine, N,N'-diphenyl-N,N'-bis(4-isopropylphenyl)pyrene-1,6-diamine, N,N'-diphenyl- N,N'-bis(4-t-butylphenyl)pyrene-1,6-diamine, N,N'-bis(4-isopropylphenyl)-N,N'-di(p-tolyl)pyrene-1 ,6-diamine, N,N,N',N'-tetrakis(3,4-dimethylphenyl)-3,8-diphenylpyrene-1,6-diamine, N,N,N,N-tetraphenyl pyrene-1,8-diamine, N,N'-bis(biphenyl-4-yl)-N,N'-diphenylpyrene-1,8-diamine, N ¹ ,N ⁶ -diphenyl-N ¹ , N ⁶ -bis-(4-trimethylsilanyl-phenyl)-1H,8H-pyrene-1,6-diamine; and the like.

Further, examples of the anthracene type include N,N,N,N-tetraphenylanthracene-9,10-diamine, N,N,N',N'-tetra(p-tolyl)anthracene-9,10-diamine, N ,N,N',N'-tetra(m-tolyl)anthracene-9,10-diamine, N,N,N',N'-tetrakis(4-isopropylphenyl)anthracene-9,10-diamine, N,N'-diphenyl-N,N'-di(p-tolyl)anthracene-9,10-diamine, N,N'-diphenyl-N,N'-di(m-tolyl)anthracene-9, 10-diamine, N,N'-diphenyl-N,N'-bis(4-ethylphenyl)anthracene-9,10-diamine, N,N'-diphenyl-N,N'-bis(4-ethyl Phenyl) anthracene-9,10-diamine, N,N'-diphenyl-N,N'-bis(4-isopropylphenyl)anthracene-9,10-diamine, N,N'-diphenyl-N,N '-Bis(4-t-butylphenyl)anthracene-9,10-diamine, N,N'-bis(4-isopropylphenyl)-N,N'-di(p-tolyl)anthracene-9,10- Diamine, 2,6-di-t-butyl-N,N,N',N'-tetra(p-tolyl)anthracene-9,10-diamine, 2,6-di-t-butyl-N,N' -diphenyl-N,N'-bis(4-isopropylphenyl)anthracene-9,10-diamine, 2,6-di-t-butyl-N,N'-bis(4-isopropylphenyl)-N ,N'-di(p-tolyl)anthracene-9,10-diamine, 2,6-dicyclohexyl-N,N'-bis(4-isopropylphenyl)-N,N'-di(p-tolyl) ) anthracene-9,10-diamine, 2,6-dicyclohexyl-N,N'-bis(4-isopropylphenyl)-N,N'-bis(4-t-butylphenyl)anthracene-9,10 -diamine, 9,10-bis(4-diphenylamino-phenyl)anthracene, 9,10-bis(4-di(1-naphthylamino)phenyl)anthracene, 9,10-bis(4-di(2) -naphthylamino)phenyl)anthracene, 10-di-p-tolylamino-9-(4-di-p-tolylamino-1-naphthyl)anthracene, 10-diphenylamino-9-(4-diphenyl amino-1-naphthyl)anthracene, 10-diphenylamino-9-(6-diphenylamino-2-naphthyl)anthracene, and the like.

In addition, [4-(4-diphenylamino-phenyl)naphthalen-1-yl]-diphenylamine, [6-(4-diphenylamino-phenyl)naphthalen-2-yl]-diphenylamine, 4 ,4'-bis[4-diphenylaminonaphthalen-1-yl]biphenyl, 4,4'-bis[6-diphenylaminonaphthalen-2-yl]biphenyl, 4,4"-bis[4- Diphenylaminonaphthalen-1-yl]-p-terphenyl, 4,4"-bis[6-diphenylaminonaphthalen-2-yl]-p-terphenyl, etc. are mentioned.

Moreover, you may use the aromatic amine derivative described in Unexamined-Japanese-Patent No. 2006-156888 etc.

Examples of the coumarin derivative include coumarin-6 and coumarin-334.

Moreover, you may use the coumarin derivative described in Unexamined-Japanese-Patent No. 2004-43646, Unexamined-Japanese-Patent No. 2001-76876, Unexamined-Japanese-Patent No. 6-298758, etc.

The following DCM, DCJTB, etc. are mentioned as a pyran derivative.

In addition, Japanese Patent Laid-Open No. 2005-126399, Japanese Patent Laid-Open No. 2005-097283, Japanese Patent Laid-Open No. 2002-234892, Japanese Patent Laid-Open No. 2001-220577, Japanese Patent Laid-Open Nos. You may use the pyran derivatives described in 2001-081090 and Japanese Unexamined Patent Publication No. 2001-052869, etc.

<Electron injection layer and electron transport layer in organic electroluminescent element>

The electron injection layer 107 serves to efficiently inject electrons moving from the cathode 108 into the light emitting layer 105 or the electron transport layer 106 . The electron transport layer 106 serves to efficiently transport electrons injected from the cathode 108 or electrons injected from the cathode 108 through the electron injection layer 107 to the light emitting layer 105 . The electron transport layer 106 and the electron injection layer 107 are each formed by laminating and mixing one or two or more types of electron transporting/injecting materials, or a mixture of an electron transporting/injecting material and a polymer binder.

The electron injection/transport layer is a layer in charge of injecting and transporting electrons from the cathode, and it is preferable that the electron injection efficiency is high and the injected electrons are transported efficiently. For this purpose, it is preferable that the material is a material having high electron affinity, high electron mobility, excellent stability, and difficult to generate trap impurities during production and use. However, when the hole and electron transport balance is considered, the effect of improving the luminous efficiency even if the electron transport capacity is not very high when the main role is to effectively block the flow of the holes from the anode to the cathode side without recombination has equal to that of materials with high electron transport capacity. Therefore, the electron injection/transport layer in this embodiment may also contain the function of the layer which can block|block the movement of a hole efficiently.

As the material (electron transport material) for forming the electron transport layer 106 or the electron injection layer 107 , the polycyclic aromatic compound represented by the above formula (1) can be used. In addition, in the photoconductive material, it can be arbitrarily selected and used from a compound conventionally used as an electron transport compound, and a known compound used for an electron injection layer and an electron transport layer of an organic electroluminescent device.

Examples of the material used for the electron transport layer or the electron injection layer include a compound consisting of an aromatic ring or heteroaromatic ring composed of at least one atom selected from carbon, hydrogen, oxygen, sulfur, silicon and phosphorus, pyrrole derivatives and condensed ring derivatives thereof, and It is preferable to contain 1 or more types selected from the metal complex which has electron-accepting nitrogen. Specifically, condensed ring derivatives such as naphthalene and anthracene, styryl aromatic ring derivatives typified by 4'4-bis(diphenylethenyl)biphenyl, perinone derivatives, coumarin derivatives, naphthalimide derivatives, Quinone derivatives, such as anthraquinone and diphenoquinone, a phosphoroxide derivative, a carbazole derivative, an indole derivative, etc. are mentioned. Examples of the metal complex having electron-accepting nitrogen include hydroxyazole complexes such as hydroxyphenyloxazole complex, azomethine complex, tropolone metal complex, flavonol metal complex, and benzoquinoline metal complex. These materials may be used alone, or may be used in combination with other materials.

In addition, specific examples of other electron transport compounds include pyridine derivatives, naphthalene derivatives, anthracene derivatives, phenanthroline derivatives, perinone derivatives, coumarin derivatives, naphthalimide derivatives, anthraquinone derivatives, diphenoquinone derivatives, diphenylquinone derivatives, Perylene derivatives, oxadiazole derivatives (1,3-bis[(4-t-butylphenyl)1,3,4-oxadiazolyl]phenylene, etc.), thiophene derivatives, triazole derivatives (N-naphthyl) -2,5-diphenyl-1,3,4-triazole, etc.), thiadiazole derivatives, metal complexes of auxin derivatives, quinolinol-based metal complexes, quinoxaline derivatives, polymers of quinoxaline derivatives, benzazole compounds, Gallium complex, pyrazole derivatives, perfluorinated phenylene derivatives, triazine derivatives, pyrazine derivatives, benzoquinoline derivatives (2,2'-bis(benzo[h]quinolin-2-yl)-9,9'-spi Robbiefluorene, etc.), imidazopyridine derivatives, borane derivatives, benzoimidazole derivatives (tris(N-phenylbenzoimidazol-2-yl)benzene, etc.), benzoxazole derivatives, benzothiazole derivatives, quinoline derivatives, ter Oligopyridine derivatives such as pyridine, bipyridine derivatives, terpyridine derivatives (1,3-bis(4'-(2,2':6'2"-terpyridinyl))benzene, etc.), naphthyridine derivatives (bis( 1-naphthyl)-4-(1,8-naphthyridin-2-yl)phenylphosphine oxide, etc.), aldazine derivatives, carbazole derivatives, indole derivatives, phosphoroxide derivatives, bisstyryl derivatives, etc. have.

It is also possible to use metal complexes having electron-accepting nitrogen, for example, hydroxyazole complexes such as quinolinol-based metal complexes and hydroxyphenyloxazole complexes, azomethine complexes, tropolone metal complexes, and flavonol metal complexes. and a benzoquinoline metal complex.

The above-mentioned materials may be used alone or may be used in combination with other materials.

Among the above-mentioned materials, a quinolinol-based metal complex, a bipyridine derivative, a phenanthroline derivative or a borane derivative is preferable.

The quinolinol-based metal complex is a compound represented by the following formula (E-1).

wherein R ¹ to R ⁶ are each independently hydrogen, fluorine, alkyl, aralkyl, alkenyl, cyano, alkoxy or aryl, M is Li, Al, Ga, Be or Zn, and n is 1 to 3 of is an integer

Specific examples of the quinolinol-based metal complex include 8-quinolinollithium, tris(8-quinolinolate)aluminum, tris(4-methyl-8-quinolinolate)aluminum, and tris(5-methyl-8-quinolinolate). Nolinolate)aluminum, tris(3,4-dimethyl-8-quinolinolate)aluminum, tris(4,5-dimethyl-8-quinolinolate)aluminum, tris(4,6-dimethyl-8- Quinolinolate)aluminum, bis(2-methyl-8-quinolinolate)(phenolate)aluminum, bis(2-methyl-8-quinolinolate)(2-methylphenolate)aluminum, bis( 2-methyl-8-quinolinolate)(3-methylphenolate)aluminum, bis(2-methyl-8-quinolinolate)(4-methylphenolate)aluminum, bis(2-methyl-8- Quinolinolate)(2-phenylphenolate)aluminum, bis(2-methyl-8-quinolinolate)(3-phenylphenolate)aluminum, bis(2-methyl-8-quinolinolate)( 4-phenylphenolate)aluminum, bis(2-methyl-8-quinolinolate)(2,3-dimethylphenolate)aluminum, bis(2-methyl-8-quinolinolate)(2,6- Dimethylphenolate)aluminum, bis(2-methyl-8-quinolinolate)(3,4-dimethylphenolate)aluminum, bis(2-methyl-8-quinolinolate)(3,5-dimethylphenol rate)aluminum, bis(2-methyl-8-quinolinolate)(3,5-di-t-butylphenolate)aluminum, bis(2-methyl-8-quinolinolate)(2,6- Diphenylphenolate)aluminum, bis(2-methyl-8-quinolinolate)(2,4,6-triphenylphenolate)aluminum,bis(2-methyl-8-quinolinolate)(2, 4,6-trimethylphenolate)aluminum, bis(2-methyl-8-quinolinolate)(2,4,5,6-tetramethylphenolate)aluminum, bis(2-methyl-8-quinolinol rate)(1-naphtolate)aluminum, bis(2-methyl-8-quinolinolate)(2-naphtolate)aluminum, bis(2,4-dimethyl-8-quinolinolate)(2-phenyl Phenolate)aluminum, bis(2,4-dimethyl-8-quinolinolate)(3-phenylphenolate)aluminum, bis(2,4-dimethyl-8-quinolinolate)(4-phenylphenolate) )Aluminum, bis(2,4-dimethyl-8-quinolinolate) (3,5-dimethylphenolate) t)aluminum, bis(2,4-dimethyl-8-quinolinolate)(3,5-di-t-butylphenolate)aluminum, bis(2-methyl-8-quinolinolate)aluminum-μ -oxo-bis(2-methyl-8-quinolinolate)aluminum, bis(2,4-dimethyl-8-quinolinolate)aluminum-μ-oxo-bis(2,4-dimethyl-8-qui Nolinolate)aluminum, bis(2-methyl-4-ethyl-8-quinolinolate)aluminum-μ-oxo-bis(2-methyl-4-ethyl-8-quinolinolate)aluminum, bis( 2-Methyl-4-methoxy-8-quinolinolate)aluminum-μ-oxo-bis(2-methyl-4-methoxy-8-quinolinolate)aluminum, bis(2-methyl-5- Cyano-8-quinolinolate)aluminum-μ-oxo-bis(2-methyl-5-cyano-8-quinolinolate)aluminum, bis(2-methyl-5-trifluoromethyl-8 -quinolinolate)aluminum-μ-oxo-bis(2-methyl-5-trifluoromethyl-8-quinolinolate)aluminum, bis(10-hydroxybenzo[h]quinoline)beryllium, etc. can

The bipyridine derivative is a compound represented by the following formula (E-2).

In the formula, G represents a simple number of bonds or an n-valent coupling group, and n is an integer of 2 to 8. In addition, the carbon not used for the pyridine-pyridine or pyridine-G bond may be substituted with aryl, heteroaryl, alkyl or cyano.

As G in general formula (E-2), the thing of the following structural formula is mentioned, for example. In addition, R in the following structural formula is each independently hydrogen, methyl, ethyl, isopropyl, cyclohexyl, phenyl, 1-naphthyl, 2-naphthyl, biphenylyl or terphenylyl.

Specific examples of the pyridine derivative include 2,5-bis(2,2'-pyridin-6-yl)-1,1-dimethyl-3,4-diphenylsilol, 2,5-bis(2,2'-pyridine) -6-yl)-1,1-dimethyl-3,4-dimethylsilol, 2,5-bis(2,2'-pyridin-5-yl)-1,1-dimethyl-3,4- Diphenylsilol, 2,5-bis(2,2'-pyridin-5-yl)-1,1-dimethyl-3,4-dimethylsilol, 9,10-di(2,2'- Pyridin-6-yl)anthracene, 9,10-di(2,2'-pyridin-5-yl)anthracene, 9,10-di(2,3'-pyridin-6-yl)anthracene, 9,10- di(2,3'-pyridin-5-yl)anthracene, 9,10-di(2,3'-pyridin-6-yl)-2-phenylanthracene, 9,10-di(2,3'-pyridine -5-yl)-2-phenylanthracene, 9,10-di(2,2'-pyridin-6-yl)-2-phenylanthracene, 9,10-di(2,2'-pyridin-5-yl) )-2-phenylanthracene, 9,10-di(2,4'-pyridin-6-yl)-2-phenylanthracene, 9,10-di(2,4'-pyridin-5-yl)-2- Phenylanthracene, 9,10-di(3,4'-pyridin-6-yl)-2-phenylanthracene, 9,10-di(3,4'-pyridin-5-yl)-2-phenylanthracene, 3 ,4-diphenyl-2,5-di(2,2'-pyridin-6-yl)thiophene, 3,4-diphenyl-2,5-di(2,3'-pyridin-5-yl) thiophene, 6'6"-di(2-pyridyl)2,2':4',4":2",2"'-quaterpyridine, etc. are mentioned.

A phenanthroline derivative is a compound represented by the following formula (E-3-1) or (E-3-2).

wherein R ¹ to R ⁸ are each independently hydrogen, alkyl (methyl, ethyl, isopropyl, hydroxyethyl, methoxymethyl, trifluoromethyl, t-butyl, cyclopentyl, cyclohexyl, benzyl, etc.), alkyl Oxy (methoxy, ethoxy, isopropoxy, butoxy, etc.), aryloxy (phenoxy, 1-naphthyloxy, 4-tolyloxy, etc.), halogen (fluorine, chlorine, bromine, iodine, etc.), aryl ( Phenyl, naphthyl, p-tolyl, p-chlorophenyl, etc.), alkylthio (methylthio, ethylthio, isopropylthio, etc.), arylthio (phenylthio, etc.), cyano, nitro, heterocyclic (pyrrole, p- rollidyl, pyrazolyl, imidazolyl, pyridyl, benzimidazolyl, benzthiazolyl, benzooxazolyl, etc.), etc. are mentioned, Preferably they are alkyl or halogen, More preferably, they are methyl, ethyl, iso. It is propyl or fluorine, and adjacent groups may combine with each other to form a condensed ring, G represents a simple number of bonds or an n-valent linking group, and n is an integer of 2 to 8. Further, examples of G in the formula (E-3-2) include the same ones as described in the section on bipyridine derivatives. In addition, in the above formula (E-3-2), it bonds to G at any one of R ¹ to R ⁸ .

Specific examples of the phenanthroline derivative include 4,7-diphenyl-1,10-phenanthroline, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, 9,10-di(1 ,10-phenanthroline-2-yl)anthracene, 2,6-di(1,10-phenanthroline-5-yl)pyridine, 1,3,5-tri(1,10-phenanthroline-5 -yl)benzene, 9,9'-difluoro-bi(1,10-phenanthroline-5-yl), vasocubroin or 1,3-bis(2-phenyl-1,10-phenantrol Lin-9-yl) benzene and the like.

In particular, the case where the phenanthroline derivative is used for the electron transport layer and the electron injection layer will be described. In order to obtain stable light emission over a long period of time, a material excellent in thermal stability and thin film formation is desired. Among phenanthroline derivatives, the substituent itself has a three-dimensional structure, or the structure with a phenanthroline skeleton or with an adjacent substituent. It is preferable to have a three-dimensional three-dimensional structure by repulsion, or to link a plurality of phenanthroline skeletons. Further, when linking a plurality of phenanthroline skeletons, compounds containing a conjugated bond, a substituted or unsubstituted aromatic hydrocarbon, or a substituted or unsubstituted aromatic heterocycle in the linking unit are more preferable.

The borane derivative is a compound represented by the following formula (E-4), and in detail, it is disclosed in Japanese Patent Laid-Open No. 2007-27587.

In the formula, R ¹¹ and R ¹² are each independently hydrogen, alkyl, optionally substituted aryl, substituted silyl, optionally substituted nitrogen-containing heterocycle or cyano, and R ¹³ to R ¹⁶ are each independently optionally substituted alkyl or optionally substituted aryl, X is optionally substituted arylene, Y is optionally substituted C16 or less aryl, substituted boril or optionally substituted carbazolyl; , and n are each independently an integer from 0 to 3. Moreover, as a substituent in the case of "which may be substituted" or "it is substituted," aryl, heteroaryl, alkyl, etc. are mentioned.

Among the compounds represented by the above formula (E-4), compounds represented by the following formula (E-4-1), and also represented by the following formulas (E-4-1-1) to (E-4-1-4) The compound used is preferred. Specific examples include 9-[4-(4-dimethylborylnaphthalen-1-yl)phenyl]carbazole, 9-[4-(4-dimethylborylnaphthalen-1-yl)naphthalen-1-yl]carbazole Bazole etc. are mentioned.

In the formula, R ¹¹ and R ¹² are each independently hydrogen, alkyl, optionally substituted aryl, substituted silyl, optionally substituted nitrogen-containing heterocycle or cyano, and R ¹³ to R ¹⁶ are each independently optionally substituted alkyl or optionally substituted aryl, R ²¹ and R ²² are each independently hydrogen, alkyl, optionally substituted aryl, substituted silyl, optionally substituted nitrogen-containing heterocycle or cyano one or more of, X ¹ is optionally substituted arylene having 20 or less carbon atoms, n is each independently an integer of 0 to 3, and m is each independently an integer of 0 to 4. Moreover, as a substituent in the case of "which may be substituted" or "it is substituted," aryl, heteroaryl, alkyl, etc. are mentioned.

In each formula, R ³¹ to R ³⁴ are each independently any one of methyl, isopropyl, or phenyl, and R ³⁵ and R ³⁶ are each independently any one of hydrogen, methyl, isopropyl, or phenyl.

Among the compounds represented by the formula (E-4), a compound represented by the following formula (E-4-2) and a compound represented by the following formula (E-4-2-1) are preferable.

In the formula, R ¹¹ and R ¹² are each independently at least one of hydrogen, alkyl, optionally substituted aryl, substituted silyl, optionally substituted nitrogen-containing heterocycle, or cyano, and R ¹³ to R ¹⁶ are each independently is optionally substituted alkyl or optionally substituted aryl, X ¹ is optionally substituted arylene having 20 or less carbon atoms, and n is each independently an integer of 0 to 3. Moreover, as a substituent in the case of "which may be substituted" or "it is substituted," aryl, heteroaryl, alkyl, etc. are mentioned.

In the formula, R ³¹ to R ³⁴ are each independently any one of methyl, isopropyl, or phenyl, and R ³⁵ and R ³⁶ are each independently any one of hydrogen, methyl, isopropyl, or phenyl.

Among the compounds represented by the formula (E-4), a compound represented by the following formula (E-4-3), and a compound represented by the following formula (E-4-3-1) or (E-4-3-2) The compound used is preferred.

In the formula, R ¹¹ and R ¹² are each independently at least one of hydrogen, alkyl, optionally substituted aryl, substituted silyl, optionally substituted nitrogen-containing heterocycle, or cyano, and R ¹³ to R ¹⁶ are each independently is optionally substituted alkyl or optionally substituted aryl, X ¹ is optionally substituted arylene having 10 or less carbon atoms, Y ¹ is optionally substituted aryl having 14 or less carbon atoms, and n is each independently 0 It is an integer of ~3. Moreover, as a substituent in the case of "which may be substituted" or "it is substituted," aryl, heteroaryl, alkyl, etc. are mentioned.

In each formula, R ³¹ to R ³⁴ are each independently any one of methyl, isopropyl, or phenyl, and R ³⁵ and R ³⁶ are each independently any one of hydrogen, methyl, isopropyl, or phenyl.

A benzimidazole derivative is a compound represented by the following formula (E-5).

In the formula, Ar ¹¹ to Ar ¹³ are each independently hydrogen or optionally substituted aryl having 6 to 30 carbon atoms. Examples of the substituent in the case of "may be substituted" include aryl, heteroaryl, alkyl or cyano. Particularly preferred are benzoimidazole derivatives wherein Ar ¹¹ is anthryl optionally substituted with aryl, heteroaryl, alkyl or cyano.

Specific examples of aryl having 6 to 30 carbon atoms include phenyl, 1-naphthyl, 2-naphthyl, acenaphthylene-1-yl, acenaphthylene-3-yl, acenaphthylene-4-yl, acenaphthylene- 5-yl, fluoren-1-yl, fluoren-2-yl, fluoren-3-yl, fluoren-4-yl, fluoren-9-yl, phenalen-1-yl, phenalen-2 -yl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl, 4-phenanthryl, 9-phenanthryl, 1-anthryl, 2-anthryl, 9-anthryl, fluoranthen-1-yl , fluoranthen-2-yl, fluoranten-3-yl, fluoranten-7-yl, fluoranten-8-yl, triphenylen-1-yl, triphenylen-2-yl, pyrene -1-yl, pyren-2-yl, pyren-4-yl, chrysen-1-yl, chrysen-2-yl, chrysen-3-yl, chrysen-4-yl, chrysen-5- Yl, chrysen-6-yl, naphthacen-1-yl, naphthacen-2-yl, naphthacen-5-yl, perylene-1-yl, perylene-2-yl, perylene-3-yl , pentasen-1-yl, pentasen-2-yl, pentasen-5-yl, pentacen-6-yl.

Specific examples of the benzimidazole derivative include 1-phenyl-2-(4-(10-phenylanthracen-9-yl)phenyl)-1H-benzo[d]imidazole, 2-(4-(10-(naphthalene-) 2-yl) anthracen-9-yl)phenyl)-1-phenyl-1H-benzo[d]imidazole, 2-(3-(10-(naphthalen-2-yl)anthracen-9-yl)phenyl)- 1-phenyl-1H-benzo[d]imidazole, 5-(10-(naphthalen-2-yl)anthracen-9-yl)-1,2-diphenyl-1H-benzo[d]imidazole, 1- (4-(10-(naphthalen-2-yl)anthracen-9-yl)phenyl)-2-phenyl-1H-benzo[d]imidazole, 2-(4-(9,10-di(naphthalene-2) -yl) anthracen-2-yl)phenyl)-1-phenyl-1H-benzo[d]imidazole, 1-(4-(9,10-di(naphthalen-2-yl)anthracen-2-yl)phenyl )-2-phenyl-1H-benzo[d]imidazole, 5-(9,10-di(naphthalen-2-yl)anthracen-2-yl)-1,2-diphenyl-1H-benzo[d] is imidazole.

The electron transport layer or the electron injection layer may further contain a substance capable of reducing the material forming the electron transport layer or the electron injection layer. Various types of reducing substances are used as long as they have a certain reducing property, for example, alkali metals, alkaline earth metals, rare earth metals, alkali metal oxides, alkali metal halides, alkaline earth metal oxides, alkaline earth metal halides, At least one selected from the group consisting of oxides of rare earth metals, halides of rare earth metals, organic complexes of alkali metals, organic complexes of alkaline earth metals and organic complexes of rare earth metals may be suitably used.

Preferred reducing substances include alkali metals such as Na (work function 2.36 eV), K (work function 2.28 eV), Rb (work function 2.16 eV) or Cs (work function 1.95 eV), Ca (work function 2.9 eV), Sr and alkaline earth metals such as (work function 2.0 to 2.5 eV) or Ba (work function 2.52 eV), particularly preferably having a work function of 2.9 eV or less. Among these, a more preferable reducing substance is an alkali metal of K, Rb or Cs, more preferably Rb or Cs, and most preferably Cs. These alkali metals have particularly high reducing ability, and by adding a relatively small amount to a material for forming the electron transport layer or electron injection layer, it is possible to improve the luminance of light emission and increase the lifespan of the organic EL device. In addition, as a reducing substance having a work function of 2.9 eV or less, a combination of two or more alkali metals is also preferable, and a combination including Cs, for example, Cs and Na, Cs and K, Cs and Rb, or Cs, Na and K A combination is preferred. By containing Cs, the reducing ability can be efficiently exhibited, and by addition to a material for forming the electron transport layer or the electron injection layer, the emission luminance and the lifespan of the organic EL device can be improved.

<Cathode in organic electroluminescent element>

The cathode 108 serves to inject electrons into the emission layer 105 via the electron injection layer 107 and the electron transport layer 106 .

The material for forming the cathode 108 is not particularly limited as long as it is a material capable of efficiently injecting electrons into the organic layer, but the same material as the material for forming the anode 102 may be used. Among them, metals such as tin, indium, calcium, aluminum, silver, copper, nickel, chromium, gold, platinum, iron, zinc, lithium, sodium, potassium, cesium and magnesium or their alloys (magnesium-silver alloy, magnesium-indium) alloys, aluminum-lithium alloys such as lithium fluoride/aluminum, etc.) are preferable. In order to increase electron injection efficiency and improve device characteristics, lithium, sodium, potassium, cesium, calcium, magnesium, or an alloy containing these low work function metals is effective. However, these low work function metals are generally unstable in the atmosphere. In order to improve this point, for example, a method of using an electrode with high stability by doping an organic layer with a small amount of lithium, cesium, or magnesium is known. As other dopants, inorganic salts such as lithium fluoride, cesium fluoride, lithium oxide and cesium oxide can also be used. However, it is not limited to these.

In addition, for electrode protection, metals such as platinum, gold, silver, copper, iron, tin, aluminum and indium or alloys using these metals, inorganic substances such as silica, titania and silicon nitride, polyvinyl alcohol, vinyl chloride, hydrocarbon-based polymers A preferable example of laminating a compound or the like is exemplified. The method for manufacturing these electrodes is not particularly limited as long as conduction can be achieved, such as resistance heating vapor deposition, electron beam vapor deposition, sputtering, ion plating and coating.

<Binder that can be used in each layer>

The materials used for the above hole injection layer, hole transport layer, light emitting layer, electron transport layer and electron injection layer can form each layer independently, and as a polymer binder, polyvinyl chloride, polycarbonate, polystyrene, poly(N-vinylcar Bazole), polymethyl methacrylate, polybutyl methacrylate, polyester, polysulfone, polyphenylene oxide, polybutadiene, hydrocarbon resin, ketone resin, phenoxy resin, polyamide, ethyl cellulose, vinyl acetate resin, ABS Solvent-soluble resins such as resins and polyurethane resins, phenol resins, xylene resins, petroleum resins, urea resins, melamine resins, unsaturated polyester resins, alkyd resins, epoxy resins, silicone resins, etc. It is possible.

<Method for manufacturing organic electroluminescent device>

Each layer constituting the organic electroluminescent device is formed by depositing the target material of each layer by a method such as vapor deposition, resistance heating vapor deposition, electron beam vapor deposition, sputtering, molecular lamination, printing, spin coating or casting, and coating. It can be formed by There is no limitation in particular about the film thickness of each layer formed in this way, Although it can set suitably according to the property of a material, Usually, it is the range of 2 nm - 5,000 nm. The film thickness can be usually measured with a crystal oscillation type film thickness measuring device or the like. In the case of thin film formation using the vapor deposition method, the deposition conditions differ depending on the type of material, the target crystal structure and association structure of the film, and the like. The deposition conditions are generally: heating temperature of the crucible for deposition +50~+400℃, vacuum degree ^10-6 ~ ^10-3Pa , deposition rate 0.01~50nm/sec, substrate temperature -150~+300℃, film thickness 2nm~5㎛ It is desirable to set it appropriately in the range of

Next, as an example of a method of manufacturing an organic electroluminescent device, a light emitting layer/electron transport layer/electron injection layer/cathode composed of an anode/hole injection layer/hole transport layer/host material and a dopant material. explain about A thin film of an anode material is formed on a suitable substrate by a vapor deposition method or the like to prepare an anode, and then thin films of a hole injection layer and a hole transport layer are formed on the anode. A thin film is formed by co-depositing a host material and a dopant material thereon to form a light emitting layer, an electron transport layer and an electron injection layer are formed on the light emitting layer, and a thin film made of a material for a cathode is formed by vapor deposition or the like to form a cathode. of the organic electroluminescent device is obtained. In addition, in the manufacture of the above-described organic electroluminescent device, it is also possible to manufacture in the order of the cathode, the electron injection layer, the electron transport layer, the light emitting layer, the hole transport layer, the hole injection layer, the anode by reversing the manufacturing order.

When a DC voltage is applied to the organic electroluminescent device obtained in this way, the anode may be applied with the polarity of + and the cathode -, and when a voltage of about 2 to 40 V is applied, the transparent or translucent electrode side (anode or cathode, and both) can be observed. In addition, this organic electroluminescent element emits light even when a pulse current or an alternating current is applied. In addition, the waveform of the alternating current to be applied may be arbitrary.

<Application example of organic electroluminescent device>

Also, the present invention can be applied to a display device having an organic electroluminescent device or a lighting device having an organic electroluminescent device.

A display device or a lighting device having an organic electroluminescent element can be manufactured by a known method such as connecting the organic electroluminescent element of the present embodiment with a known driving device, and can be manufactured by known methods such as direct current driving, pulse driving, alternating current driving, etc. It can be driven by appropriately using the driving method.

As a display apparatus, flexible displays, such as panel displays, such as a color flat panel display, and a flexible color organic electroluminescence (EL) display, etc. are mentioned, for example (For example, Unexamined-Japanese-Patent No. 10-335066, Japan See Patent Laid-Open No. 2003-321546, Japanese Patent Laid-Open No. 2004-281086, etc.). Moreover, as a display system of a display, a matrix and/or a segment system etc. are mentioned, for example. In addition, the matrix display and the segment display may coexist in the same panel.

A matrix means that pixels for display are two-dimensionally arranged, such as a grid shape or a mosaic shape, and a character or image is displayed as a set of pixels. The shape or size of a pixel is determined according to its use. For example, a square pixel having a side of 300 μm or less is usually used for displaying images and characters on a PC, monitor, and TV, and in the case of a large display such as a display panel, pixels with a side of the order of mm are used. In case of black and white display, pixels of the same color should be arranged, but in case of color display, pixels of red, green, and blue are arranged and displayed. In this case, there are typically a delta type and a stripe type. And as a driving method of this matrix, either a line sequential driving method or an active matrix may be used. The line-sequential driving has an advantage in that it has a simple structure, but in some cases the active matrix is superior when the operating characteristics are taken into consideration.

In the case of the segment method (type), a predetermined area is emitted by forming a pattern to display predetermined information. For example, the time and temperature display in a digital watch or thermometer, the operation state display of an audio device, an electronic cooker, etc., and the panel display of an automobile, etc. are mentioned.

Examples of the lighting device include lighting devices such as indoor lighting, backlights of liquid crystal display devices, etc. See Korean Patent Publication No. 2004-119211, etc.). The backlight is mainly used for the purpose of improving the visibility of a display device that does not emit light by itself, and is used in a liquid crystal display device, a watch, an audio device, an automobile panel, a display panel, and a cover. In particular, considering that it is difficult to reduce the thickness of a liquid crystal display device, in particular, as a backlight for PC use, in which thickness reduction is a problem, because the conventional backlight consists of a fluorescent lamp or a light guide plate, the backlight using the light emitting device of this embodiment is thin and lightweight. is characterized by

Example

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited in any way by these examples.

<Synthesis of compound intermediates used in Examples>

[Intermediate 1]

2-bromo-6-methoxynaphthalene (24.0 g), [1,1'-(bisdiphenylphosphino) ferrocene] dichloronickel (II) (1.38 g), and cyclopentylmethyl ether (125 ml) The mixture was stirred under a nitrogen atmosphere, and a 1M solution of hexylmagnesium bromide in tetrahydrofuran (150 ml) was slowly added dropwise so that the internal temperature did not exceed 40° C., followed by stirring for 4 hours. After cooling with ice water, water was slowly added dropwise, followed by dropwise addition of 3M hydrochloric acid for neutralization, toluene was added to separate the mixture, and the aqueous layer was extracted with toluene. The combined toluene layer was washed with water, dried over anhydrous sodium sulfate, the drying agent was filtered, and the filtrate was concentrated under reduced pressure to obtain 2-hexyl-6-methoxynaphthalene of Intermediate 1 (24.5 g).

[Intermediate 2]

A mixture of Intermediate 1 (24.5 g), pyridine hydrochloride (58.4 g) and N-methyl-2-pyrrolidone (100 ml) was heated in an oil bath at 200° C. under a nitrogen atmosphere, while distilling off the resulting pyridine 1 time was stirred. After cooling, water and toluene were added to separate the liquid, and the aqueous layer was extracted with toluene. The combined toluene layer was washed with water and dried over sodium sulfate, and the filtrate was concentrated under reduced pressure to obtain 6-hexylnaphthalen-2-ol (23.1 g) of Intermediate 2 (23.1 g).

[Intermediate 3]

The mixture of Intermediate 2 (23.1 g) and pyridine was stirred under ice cooling, and trifluoromethanesulfonic anhydride (42.5 g) was added dropwise so that the internal temperature did not exceed 10°C. After stirring at room temperature for 30 minutes, the mixture was cooled, separated by adding water and toluene, and the aqueous layer was extracted with toluene. The combined toluene layers were washed with water, dried over sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure to obtain 6-hexylnaphthalen-2-yl trifluoromethanesulfonate of Intermediate 3 (33.0 g).

[Intermediate 4]

Intermediate 3 (33.0 g), bispinacolatodiboron (27.9 g), potassium acetate (27.0 g), potassium carbonate (3.16 g), [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium (2.01) g), and a mixture of cyclopentylmethyl ether (330 ml) was heated and stirred for 3 hours while raising the temperature from 80°C to 100°C under a nitrogen atmosphere. The reaction mixture was passed through a silica gel shot column (PSQ-100B (150 mL), solvent: toluene). The residue obtained by concentrating the effluent under reduced pressure was washed with heptane and vacuum dried to 2-(6-hexylnaphthalen-2-yl)-4,4,5,5-tetramethyl-1,3,2-di of Intermediate 4 Oxaborolane (31.0 g) was obtained.

[Intermediate 5]

Intermediate 4 (31.0 g), 2,5-dibromopyridine (21.7 g), tetrakis(triphenylphosphine)palladium (3.17 g), potassium carbonate (25.3 g), toluene (310 ml), t-butyl A mixture of alcohol (124 ml) and water (25 ml) was stirred at reflux temperature under nitrogen atmosphere for 3 hours. After cooling, the liquid was separated, and the concentrated organic layer was dissolved in cyclopentylmethyl ether, the insoluble matter was removed by filtration, and the filtrate was concentrated to 5-bromo-2-(6-hexylnaphthalen-2-yl of Intermediate 5). ) to obtain pyridine (33 g).

[Intermediate 6]

Intermediate 5 (33 g), bispinacolatodiboron (30.2 g), potassium acetate (18.0 g), [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium (4.02 g), cyclopentylmethyl ether (330 ml), and a mixture of N,N-dimethylformamide (100 ml) was heated and stirred at 100° C. under a nitrogen atmosphere for 3 hours. The reaction mixture was passed through a silica gel shot column (PSQ-100B (150 mL), solvent: toluene). The residue obtained by concentrating the effluent under reduced pressure was washed with methanol and then heptane and dried in vacuo, followed by 2-(6-hexylnaphthalen-2-yl)-5-(4,4,5,5-tetramethyl-1 of Intermediate 6). ,3,2-dioxaborolan-2-yl)pyridine (8.3 g) was obtained.

<Synthesis of the compound used in the Examples>

[Synthesis Example 1] (Synthesis of Compound (1-1))

Intermediate 6 (3.2 g), 9,10-dibromoanthracene (1.1 g), potassium carbonate (1.8 g), [[4-(N,N-dimethylamino)phenyl]di-t-butylphosphine]dichloro A mixture of palladium (0.12 g), toluene (11 ml), t-butyl alcohol (4.4 ml) and water (0.9 ml) was heated and stirred under a nitrogen atmosphere at reflux temperature for 1.5 hours. The reaction mixture was cooled, water was added, and the solid was collected by filtration, followed by washing with water, methanol, and then ethyl acetate. After vacuum drying, three times toluene was added, heated to reflux, cooled, and the precipitates were collected by filtration and vacuum dried. Purification by sublimation under vacuum of 1×10 ^-3 Pa or less, 9,10-bis(6-(6-hexylnaphthalen-2-yl)pyridin-3-yl)anthracene of compound (1-1) (0.86 g) got

The structure of the obtained compound was confirmed by NMR spectrum.

[Synthesis Example 2] (Synthesis of Compound (1-2))

Intermediate 6 (3.7 g), 1,4-dibromonaphthalene (1.1 g), potassium carbonate (2.1 g), [[4-(N,N-dimethylamino)phenyl]di-t-butylphosphine]dichloro A mixture of palladium (0.14 g), toluene (11 ml), t-butyl alcohol (4.4 ml) and water (0.9 ml) was heated and stirred under a nitrogen atmosphere at reflux temperature for 1.5 hours. The reaction mixture was cooled, water and heptane were added, and the precipitate was collected by filtration and washed with water and then methanol. After vacuum drying, sublimation and purification under vacuum of 1×10 ^-3 Pa or less to 1,4-bis(6-(6-hexylnaphthalen-2-yl)pyridin-3-yl)naphthalene (0.07) of compound (1-2) g) was obtained.

The structure of the obtained compound was confirmed by NMR spectrum.

<Evaluation of organic EL device>

The organic EL devices of Examples 1 and 2 were fabricated, and the driving voltage (V) and the external quantum efficiency (%) were measured when a current density of 10 mA/cm 2 was applied, respectively, and then the luminance maintenance time when driving with a constant current was measured. measured. Also, the driving voltage (V) was measured when a current density of 10 mA/cm 2 was applied to the organic EL device after the annealing treatment. Examples will be described in detail below.

In addition, there are internal quantum efficiency and external quantum efficiency in the quantum efficiency of the light emitting device. The internal quantum efficiency is the ratio of the external energy injected as electrons (or holes) to the light emitting layer of the light emitting device is purely converted into photons. On the other hand, the external quantum efficiency is calculated based on the amount of photons emitted to the outside of the light emitting device. The photons generated in the light emitting layer are partially absorbed or continuously reflected inside the light emitting device, so that the outside of the light emitting device is generated. Since it is not emitted as , the external quantum efficiency is lower than the internal quantum efficiency.

The method of measuring the external quantum efficiency is as follows. Using a 2400 type general-purpose source meter manufactured by KEITHLEY, a voltage having a current density of 10 mA/cm 2 was applied to cause the device to emit light. The spectroradiance luminance of the visible light region was measured in a direction perpendicular to the light emitting surface using a spectroradiance meter SR-3AR manufactured by TOPCON. Assuming that the light emitting surface is a perfect diffusion surface, the value obtained by dividing the measured spectral luminance of each wavelength component by the wavelength energy and multiplying by ? is the number of photons at each wavelength. Then, the total number of photons in the observed wavelength range was calculated to be the total number of photons emitted from the device. The value obtained by dividing the applied current by the amount of electricity is the number of carriers injected into the device, and the total number of photons emitted from the device divided by the number of carriers injected into the device is the external quantum efficiency.

Table 1 below shows the material configuration of each layer in the devices of Examples 1 and 2 produced.

In Table 1, "HI-1 ^" is N ⁴ ,N 4'-diphenyl-N ^{4 ,} N 4'-bis(9-phenyl-9H-carbazol-3-yl)-[1,1'-ratio phenyl]-4,4'-diamine, "HI-2" is 1,4,5,8,9,12-hexaazatriphenylene-2,3,6,7,10,11-hexacarbonitrile; "HT" is N-([1,1'-biphenyl]-4-yl)-9,9-dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)- 9H-fluoren-2-amine, "BH" is 9-phenyl-10-(4-phenylnaphthalen-1-yl)anthracene, "BD" is 7,7-dimethyl-N ⁵ ,N ⁹ -diphenyl- N ⁵ ,N ⁹ -bis(4-(trimethylsilyl)phenyl)-7H-benzo[c]fluorene-5,9-diamine. The chemical structure is shown below together with quinolinol lithium (Liq).

<Example 1: device using compound (1-1) as an electron transport material>

A 26 mm x 28 mm x 0.7 mm glass substrate (manufactured by Opto Science Co., Ltd.) obtained by polishing ITO to a thickness of 180 nm by sputtering to 150 nm was used as a transparent support substrate. This transparent support substrate was fixed to the substrate holder of a commercially available vapor deposition apparatus (manufactured by Showa Shinku Co., Ltd.), and a molybdenum vapor deposition boat containing HI-1, a molybdenum vapor deposition boat containing HI-2, and HT was placed. Molybdenum vapor deposition boat, molybdenum vapor deposition boat containing BH, molybdenum vapor deposition boat containing BD, molybdenum vapor deposition boat containing compound (1-1), molybdenum vapor deposition boat containing Liq, magnesium A molybdenum vapor deposition boat and a silver molybdenum vapor deposition boat were installed.

The following layers were sequentially formed on the ITO film of the transparent support substrate. Depressurize the vacuum chamber to 5×10 ^-4 Pa or less, and first heat a vapor deposition boat containing HI-1 and deposit it to a film thickness of 40 nm to form a first hole injection layer, and The wearing boat was heated to deposit to a film thickness of 5 nm to form a second hole injection layer, and then, a deposition boat containing HT was heated to deposit to a film thickness of 25 nm to form a hole transport layer. Next, a vapor deposition boat containing BH and a vapor deposition boat containing BD were heated at the same time to deposit a film thickness of 20 nm to form a light emitting layer. The deposition rate was controlled so that the weight ratio of BH and BD was approximately 95:5. Next, the vapor deposition boat containing the compound (1-1) was heated and vapor-deposited to a film thickness of 30 nm to form an electron transport layer. The deposition rate of each layer was 0.01 to 1 nm/sec.

Thereafter, the vapor deposition boat containing Liq was heated and vapor-deposited at a deposition rate of 0.01 to 0.1 nm/sec to a film thickness of 1 nm. Subsequently, the magnesium-containing boat and the silver-containing boat were heated at the same time and deposited to a film thickness of 100 nm to form a cathode. At this time, the deposition rate was adjusted so that the atomic ratio of magnesium and silver was 10:1, and the deposition rate was 0.01 to 2 nm/sec to obtain an organic EL device.

Moreover, the organic electroluminescent element was annealed by storing the organic electroluminescent element obtained above for 20 minutes in the thermostat set to 100 degreeC. Thereafter, the organic EL device was taken out from the constant temperature bath and cooled naturally until the temperature was lowered to room temperature.

When the characteristics of the organic EL device before annealing were measured when an ITO electrode was used as an anode and a Liq/(magnesium+silver) electrode as a cathode when a current density of 10 mA/cm2 was applied, the driving voltage was 3.75 V and the external quantum efficiency was 5.9%. it was As a result of applying a current density of 10 mA/cm 2 and performing a constant current driving test, the time to maintain luminance of 90% or more of the initial luminance was 107 hours. In addition, the driving voltage after 90% luminance lifetime was 3.98 V, and the external quantum efficiency was 4.9%.

When the characteristics of the organic EL device subjected to annealing treatment were measured with an ITO electrode as an anode and a Liq/(magnesium + silver) electrode as a cathode when a current density of 10 mA/cm 2 was applied, the driving voltage was 3.49 V and the external quantum efficiency was 5.8. was %. As a result of applying a current density of 10 mA/cm&lt;2&gt; and conducting a constant current driving test, the time for maintaining the luminance of 90% or more of the initial luminance was 173 hours. In addition, the driving voltage after 90% luminance lifetime was 3.94 V, and the external quantum efficiency was 4.9%.

The driving voltage (3.49 V) of the device subjected to the annealing treatment was lowered by 0.26 V compared to that before the annealing treatment (3.75 V), making it more stable.

<Example 2: Device in which compound (1-1) was mixed with Liq and used as an electron transport material>

An organic EL device was obtained in the same manner as in Example 1, except that the vapor deposition boat containing the compound (1-1) and the vapor deposition boat containing Liq were heated at the same time to form an electron transport layer by vapor deposition to a film thickness of 30 nm. In addition, the deposition rate was adjusted so that the weight ratio of compound (1-1) and Liq was approximately 1:1.

Moreover, the organic electroluminescent element was annealed by storing the organic electroluminescent element obtained above for 20 minutes in the thermostat set to 100 degreeC. Thereafter, the organic EL device was taken out from the constant temperature bath and cooled naturally until the temperature was lowered to room temperature.

For the organic EL device before the annealing treatment, when the characteristics are measured when an ITO electrode is used as an anode and a Liq/(magnesium + silver) electrode as a cathode when a current density of 10 mA/cm 2 is applied, the driving voltage is 3.96 V, and the external quantum efficiency is 6.7%. it was As a result of applying a current density of 10 mA/cm&lt;2&gt; and performing a constant current driving test, the time for maintaining the luminance of 90% or more of the initial luminance was 108 hours. In addition, the driving voltage after 90% luminance lifetime was 4.03 V, and the external quantum efficiency was 5.3%.

When the characteristics of the organic EL device subjected to annealing treatment were measured with an ITO electrode as an anode and a Liq/(magnesium + silver) electrode as a cathode when a current density of 10 mA/cm 2 was applied, the driving voltage was 3.19 V and the external quantum efficiency was 5.4. was %. As a result of applying a current density of 10 mA/cm 2 and performing a constant current driving test, the time for maintaining the luminance of 90% of the initial luminance was 500 hours or more. In addition, the driving voltage after 500 hours was 3.86 V, and the external quantum efficiency was 5.3%.

The driving voltage (3.19 V) of the device subjected to the annealing treatment was lowered by 0.77 V compared to that before the annealing treatment (3.96 V), making it more stable.

Table 2 summarizes the above results.

Since the organic EL device using the polycyclic aromatic compound represented by the formula (1) of the present invention is less susceptible to morphological change due to heat generation, the change in voltage before and after long-time driving is small in both the presence and absence of annealing treatment. For this reason, it is useful as an organic electroluminescent element which continuous use is assumed in the environment with large temperature change for a long period of time.

100 organic electroluminescent device
101 board
102 anode
103 hole injection layer
104 hole transport layer
105 light emitting layer
106 electron transport layer
107 electron injection layer
108 cathode

Claims (16)

A polycyclic aromatic compound represented by the following formula (1).
[Formula 1]

(of formula 1,
Ar ¹ , Ar ² and Ar ³ are each independently a divalent aromatic group having 10 to 20 carbon atoms, and in Ar ¹ , Ar ² and Ar ³ , one or more hydrogens may be substituted with a methyl group,
Ar ¹ , Ar ² and Ar ³ The total number of carbon atoms is 30 to 38,
Py ¹ and Py ² are each independently 2,5-pyridinediyl, 2,5-pyrazinediyl, 2,5-pyrimidinediyl or 2,5-pyridazinediyl, and in Py ¹ and Py ² , at least one hydrogen may be substituted with a methyl group,
The angle formed by the bonding axis between Py ¹ and Py ² bonding with Ar ¹ is 120 to 240 degrees,
R ¹ and R ² are each independently a hexyl group or a heptyl group, and an arbitrary methylene group (-CH ₂ -) may be substituted with -O- or -S- in the hexyl group or heptyl group.) According to claim 1,
Ar ¹ is naphthalenediyl or anthracenediyl, and one or more hydrogens in Ar ¹ may be substituted with a methyl group. According to claim 1,
Ar ² and Ar ³ are naphthalenediyl, and in Ar ² and Ar ³ , one or more hydrogens may be substituted with a methyl group. The method of claim 1,
Py ¹ and Py ² are 2,5-pyridinediyl, and in Py ¹ and Py ² , one or more hydrogens may be substituted with a methyl group. According to claim 1,
Ar ¹ , Ar ² , and Ar ³ A polycyclic aromatic compound in which the total number of carbon atoms is 30 to 34. The method of claim 1,
R ¹ and R ² are a hexyl group; a polycyclic aromatic compound. The method of claim 1,
A polycyclic aromatic compound represented by the following formula (1-1) or (1-2).

An electron transporting material containing the polycyclic aromatic compound according to any one of claims 1 to 7. An organic electroluminescent device comprising a pair of electrodes comprising an anode and a cathode, and an organic layer containing the compound in which the polycyclic aromatic compound according to any one of claims 1 to 7 is self-organized. A pair of electrodes comprising an anode and a cathode, a light emitting layer disposed between the pair of electrodes, and a compound in which the polycyclic aromatic compound according to any one of claims 1 to 7 self-organizes between the cathode and the light emitting layer An organic electroluminescent device having an electron transport layer and/or an electron injection layer containing 11. The method of claim 10,
At least one of the electron transport layer and the electron injection layer is an organic material containing at least one selected from the group consisting of a quinolinol-based metal complex, a pyridine derivative, a bipyridine derivative, a phenanthroline derivative, a borane derivative, and a benzoimidazole derivative. electroluminescent device. 11. The method of claim 10,
At least one of the electron transport layer and the electron injection layer may further include alkali metals, alkaline earth metals, rare earth metals, alkali metal oxides, alkali metal halides, alkaline earth metal oxides, alkaline earth metal halides, rare earth metals. An organic electroluminescent device comprising at least one selected from the group consisting of an oxide, a halide of a rare earth metal, an organic complex of an alkali metal, an organic complex of an alkaline earth metal, and an organic complex of a rare earth metal. 12. The method of claim 11,
At least one of the electron transport layer and the electron injection layer may further include alkali metals, alkaline earth metals, rare earth metals, alkali metal oxides, alkali metal halides, alkaline earth metal oxides, alkaline earth metal halides, rare earth metals. An organic electroluminescent device comprising at least one selected from the group consisting of an oxide, a halide of a rare earth metal, an organic complex of an alkali metal, an organic complex of an alkaline earth metal, and an organic complex of a rare earth metal. A display device comprising the organic electroluminescent element according to claim 9 . A lighting device provided with the organic electroluminescent element according to claim 9. A method for manufacturing an organic electroluminescent device having a pair of electrodes comprising an anode and a cathode, and an organic layer containing the compound in which the polycyclic aromatic compound according to any one of claims 1 to 7 is self-organized, the method comprising:
A method of manufacturing an organic electroluminescent device for forming an organic layer containing a self-organized polycyclic aromatic compound by depositing the organic material containing the polycyclic aromatic compound at a rate of 0.01 to 20.0 nm/sec.

Images