JP5185591B2 - Organic EL device - Google Patents

Description

  The present invention relates to an organic EL element. In particular, the present invention relates to an organic EL element including a phosphorescent light emitting layer.

An organic electroluminescent device (organic EL device) that has an organic light emitting layer between an anode and a cathode, and emits light from exciton energy generated by recombination of holes and electrons injected into the organic light emitting layer It has been known.
Such an organic EL element is expected as a light emitting element excellent in luminous efficiency, image quality, power consumption, and thin design, taking advantage of the self-luminous element.

As a further improvement of organic EL devices, there is a point of luminous efficiency. In order to increase the internal quantum efficiency, phosphorescent materials that emit light from triplet excitons have been developed, and recently phosphorescent light emission has been used. An organic element has been reported (for example, Patent Document 1).
By using such a phosphorescent material, an internal quantum efficiency of 75% or more and theoretically close to 100% can be realized, and an organic EL element with high efficiency and low power consumption can be obtained.

In addition, when using a light emitting material in an organic EL element, a doping method is known in which a host material is doped with a dopant material.
In order to efficiently generate excitons from the injected energy and efficiently link the exciton energy to light emission, a configuration is adopted in which the exciton energy generated in the host is transferred to the dopant and light emission is obtained from the dopant. The

Here, in order to perform intermolecular energy transfer from the host to the dopant, the energy gap Eg _{H of the} host needs to be larger than the energy gap Eg _{D of the} dopant.
As a material having a large triplet energy gap, CBP (4,4′-bis (N-carbazolyl) biphenyl) is typically known.
If this CBP is used as a host, a high-efficiency light-emitting element can be obtained by transferring energy to a phosphorescent material exhibiting a predetermined emission wavelength (for example, green or red).

  However, when CBP is used as a host, the luminous efficiency is remarkably improved by phosphorescence emission, but there is a problem that the device life is very short and not suitable for practical use.

On the other hand, various host materials for fluorescent dopants are known, and various host materials excellent in luminous efficiency and lifetime in combination with fluorescent dopants have been proposed.
However, in the host material for the fluorescent light emitting layer, the singlet is larger than the singlet energy gap Eg (S) of the fluorescent dopant, but the triplet energy gap Eg (T) is not necessarily large. It cannot be diverted to a phosphorescent host.
For example, anthracene derivatives, pyrene derivatives, naphthacene derivatives, and the like are well known as host materials for the fluorescent light-emitting layer, but such compounds have a triplet energy gap Eg (T) of about 1.9 eV. The energy gap is not sufficient for the emission wavelength in the visible light region of 450 nm to 750 nm, and the anthracene derivative is not suitable as a host for the phosphorescent material.

US application 2002/182441 publication

As described above, there is no known host material that can efficiently transfer energy to the phosphorescent light-emitting material and that has a practically long lifetime, which hinders the practical application of the element using the phosphorescent material. .
Accordingly, an object of the present invention is to provide a phosphorescent organic EL device having a high efficiency and a long lifetime.

  As a result of intensive studies, the present inventors have a compound having a polycyclic fused aromatic skeleton, which has a triplet energy gap Eg (T) of 2.1 eV or more and can be suitably used as a host material for a phosphorescent dopant. As a result, the present invention has been completed.

The organic EL device of the present invention is an organic EL device comprising an anode, a cathode, and an organic thin film layer provided between the anode and the cathode, wherein the organic thin film layer comprises a host and phosphorescence. A phosphorescent light-emitting layer containing a dopant, wherein the host has a substituted or unsubstituted polycyclic fused aromatic skeleton having 14 to 30 nucleus atoms, and a minimum excited triplet energy gap of 2; containing host material is 1eV than 2.7eV or less, the phosphorescent dopant may have a ligand represented by the following formula (1), the polycyclic fused aromatic skeleton is represented by the following formula (3 ), Formula (4), Formula (51), Formula (52), Formula (53), or Formula (54) .

In the organic EL device of the present invention, since the triplet energy gap of the host material is 2.1 eV or more and 2.7 eV or less, the triplet energy cap is 2.7 eV or less, more efficiently 2.5 eV or less. It is possible to cause phosphorescence emission by transferring energy to the phosphorescent dopant.
Anthracene derivatives well known as fluorescent hosts are also unsuitable as a host for red phosphorescent dopants. However, the host material of the present invention has a triplet energy gap of 2.1 eV or more, so it is effectively red. It is possible to emit a phosphorescent dopant exhibiting the following light emission.

However, although CBP, which is a well-known phosphorescent host, functions as a host for phosphorescent dopants having wavelengths shorter than green, the triplet energy gap is 2.7 eV or less in the host material of the present invention. Therefore, even phosphorescent dopants that emit green light can emit light without leakage of energy, but phosphorescent dopants that emit blue or blue-green light cannot sufficiently emit light.
In the present invention, the host material skeleton is a polycyclic fused ring, whereby the stability of the molecule can be increased and the device life can be extended.
At this time, if the number of nuclei in the skeleton is too small, the stability of the molecule is not sufficiently increased, so the number of nuclei is 14 or more. On the other hand, if the number of polycyclic fused rings is too large, the HOMO-LUMO gap And the triplet energy gap becomes less than the useful emission wavelength, so the number of nuclear atoms is 30 or less.
Thereby, it can be set as a suitable host material as a host material of the phosphorescence layer which shows a useful light emission wavelength.

Conventionally, since a host material corresponding to a phosphorescent dopant that can be widely applied to a phosphorescent dopant in a wide wavelength range from green to red has been selected, CBP having a wide triplet energy gap has been used as the host material.
However, the CBP has a problem that the triplet energy gap Eg (T) is wide but the lifetime is short.

In this regard, in the present invention, the number of nuclear atoms of the polycyclic fused aromatic skeleton is 14 to 30, and the lowest excited triplet energy gap is 2.1 eV or more and 2.7 eV or less. Although not applicable to a phosphorescent dopant host, it functions as a host for a phosphorescent dopant of 2.7 eV or less. Furthermore, if the triplet energy gap is too wide as in CBP, there is a problem that the energy gap difference is too large for the red phosphorescent dopant and the intermolecular energy transfer is not performed efficiently. According to the host of the invention, the energy gap is matched to the red phosphorescent dopant, so that the energy can be efficiently transferred from the host exciton to the phosphorescent dopant, resulting in a very efficient phosphorescent emitting layer. Can be configured.
As described above, according to the present invention, since the phosphorescent light emitting layer is formed by using the above-described host material, a phosphorescent organic EL element having high efficiency and long life can be obtained.

  In the present invention, since the compound having the ligand represented by the formula (1) is used as a phosphorescent dopant, a highly efficient and long-lived phosphorescent organic EL device can be obtained.

Here, in formula (1),
R ₃ ′ is a substituent selected from the group consisting of alkyl, heteroalkyl, aryl, heteroaryl, and aralkyl, and R ₃ ′ may be optionally substituted with one or more substituents Z;
R ₅ is a substituent selected from the group consisting of aryl and heteroaryl, said aryl or heteroaryl being unsubstituted or optionally substituted with one or more non-aromatic groups;
Ring A is an aromatic heterocyclic or fused aromatic heterocyclic ring having at least one nitrogen atom coordinated to the metal, and ring A is optionally selected by one or more non-aromatic groups. Can be replaced,
R ₃ is H, alkyl, alkenyl, alkynyl, alkylaryl, CN, CF ₃ , CnF _{2n + 1} , trifluorovinyl, CO ₂ R, C (O) R, NR ₂ , NO ₂ , OR, halo, aryl, hetero A substituent selected from the group consisting of aryl, substituted aryl, substituted heteroaryl or heterocyclic group;
R ₄ is H, alkyl, alkenyl, alkynyl, alkylaryl, CN, CF ₃ , CnF _{2n + 1} , trifluorovinyl, CO ₂ R, C (O) R, NR ₂ , NO ₂ , OR, halo, aryl, hetero A substituent selected from the group consisting of aryl, substituted aryl, substituted heteroaryl or heterocyclic group;
In addition or alternatively, R ₃ and R ₄ are taken together to independently form a fused 4-7 membered cyclic group, which can be cycloalkyl, cycloheteroalkyl, aryl, or heteroaryl And the cyclic group may be optionally substituted with one or more substituents Z,
R ₆ is H, alkyl, alkenyl, alkynyl, alkylaryl, CN, CF ₃ , CnF _{2n + 1} , trifluorovinyl, CO ₂ R, C (O) R, NR ₂ , NO ₂ , OR, halo, aryl, hetero A substituent selected from the group consisting of aryl, substituted aryl, substituted heteroaryl or heterocyclic group;
Alternatively, _{R 3} 'and _{R 6, -CR 2 -CR 2 -, -} CR = CR -, - CR 2 -, - O -, - NR -, - O-CR 2 -, - NR-CR 2 - And may be cross-linked by a group selected from -N = CR-
Each R is independently H, alkyl, alkenyl, alkynyl, heteroalkyl, aryl, heteroaryl, or aralkyl, wherein R is optionally substituted by one or more substituents Z;
Each Z is independently halogen, R ′, OR ′, N (R ′) ₂ , SR ′, C (O) R ′, C (O) OR ′, C (O) N (R ′) ₂ , CN, NO ₂ , SO ₂ , SOR ′, SO ₂ R ′, or SO ₃ R ′,
Each R ′ is independently H, alkyl, perhaloalkyl, alkenyl, alkynyl, heteroalkyl, aryl, or heteroaryl.

  “Halo” or “halogen” includes fluorine, chlorine, bromine and iodine.

“Alkyl” intends straight-chain and branched alkyl groups. Preferred alkyl groups are those containing 1 to 15 carbon atoms and include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and the like. In addition, the alkyl group can be optionally substituted with one or more substituents selected from halo, CN, CO ₂ R, C (O) R, NR ₂ , cyclic amino, NO ₂ , and OR. .

“Cycloalkyl” intends a cyclic alkyl group. Preferred cycloalkyl groups are those containing 3 to 7 carbon atoms and include cyclopropyl, cyclopentyl, cyclohexyl, and the like. In addition, the cycloalkyl group is optionally substituted with one or more substituents selected from halo, CN, CO ₂ R, C (O) R, NR ₂ , cyclic amino, NO ₂ , and OR. sell.

“Alkenyl” intends straight-chain and branched alkene groups. Preferred alkenyl groups contain 2 to 15 carbon atoms. In addition, an alkenyl group can be optionally substituted with one or more substituents selected from halo, CN, CO ₂ R, C (O) R, NR ₂ , cyclic amino, NO ₂ , and OR. .

“Alkynyl” intends straight-chain and branched alkyne groups. Preferred alkynyl groups contain 2 to 15 carbon atoms. In addition, the alkynyl group can be optionally substituted with one or more substituents selected from halo, CN, CO ₂ R, C (O) R, NR ₂ , cyclic amino, NO ₂ , and OR. .

“Alkylaryl” intends an alkyl group having an aromatic group as a substituent. In addition, the alkylaryl group is optionally substituted with one or more substituents selected from halo, CN, CO ₂ R, C (O) R, NR ₂ , cyclic amino, NO ₂ , and OR. sell.

  “Heterocyclic group” intends a non-aromatic cyclic group. Preferred heterocyclic groups are those containing 3 to 7 ring atoms containing at least one heteroatom, such as cyclic amines such as morpholine, piperidino, and rings such as tetrahydrofuran, tetrahydropyran, etc. Contains the formula ether.

  “Aryl” or “aromatic group” intends monocyclic groups and polycyclic ring systems. A polycyclic ring can have multiple rings in which two carbons are shared by two adjacent rings (the rings are “fused”), at least one of the adjacent rings being Aromatic, for example, the other ring can be cycloalkyl, cycloalkenyl, aryl, heterocycle and / or heteroaryl.

  “Heteroaryl” refers to a monocyclic heteroaromatic group that may contain from 1 to 3 heteroatoms such as pyrrole, furan, thiophene, imidazole, oxazole, thiazole, triazole, pyrazole, pyridine, pyrazine and pyrimidine, and the like. Intended. The term heteroaryl also includes polycyclic heteroaromatic systems having a plurality of rings in which two atoms are shared by two adjacent rings (the rings are “fused”). At least one of the rings is aromatic, for example, the other ring can be cycloalkyl, cycloalkenyl, aryl, heterocycle and / or heteroaryl.

  All numerical ranges, for example the ranges given by n and m, include the entire range. Thus, for example, a range of 0 to 4 includes the numerical values 0, 1, 2, 3, and 4.

The triplet energy gap Eg (T) of the material is defined as an example based on the phosphorescence emission spectrum. For example, in the present invention, the triplet energy gap Eg (T) is defined as follows. .
That is, each material is dissolved at 10 μmol / L in an EPA solvent (diethyl ether: isopentane: ethanol = 5: 5: 2 by volume ratio) to obtain a sample for phosphorescence measurement.
Then, the phosphorescence measurement sample is put in a quartz cell, cooled to 77K, irradiated with excitation light, and the wavelength of the emitted phosphorescence is measured.
A triplet energy gap Eg (T) is defined as a value obtained by drawing a tangent line to the short-wavelength rise of the obtained phosphorescence spectrum and converting the wavelength value at the intersection of the tangent line and the base line into energy.
For measurement, for example, a commercially available measuring device F-4500 (manufactured by Hitachi) can be used.
However, any value that can be defined as a triplet energy gap without departing from the gist of the present invention is acceptable, regardless of such rules.

In this specification, the terms fluorescent host and phosphorescent host are referred to as a fluorescent host when combined with a fluorescent dopant, and are referred to as a phosphorescent host when combined with a phosphorescent dopant. It is not limited to phosphorescent hosts.
In other words, in this specification, the fluorescent host means a material constituting the fluorescent light-emitting layer containing a fluorescent dopant, and does not mean a material that can be used only for the host of the fluorescent material. Similarly, the phosphorescent host means a material constituting a phosphorescent light emitting layer containing a phosphorescent dopant, and does not mean a material that can be used only as a host of the phosphorescent material.

  In the present invention, the polycyclic fused aromatic skeleton is preferably contained in the chemical structural formula as a divalent or higher valent group.

Examples of the substituent of the polycyclic fused aromatic skeleton include, for example, a halogen atom, hydroxyl group, substituted or unsubstituted amino group, nitro group, cyano group, substituted or unsubstituted alkyl group, substituted or unsubstituted alkenyl. Group, substituted or unsubstituted cycloalkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aromatic hydrocarbon group, substituted or unsubstituted aromatic heterocyclic group, substituted or unsubstituted aralkyl group, substituted Or an unsubstituted aryloxy group, a substituted or unsubstituted alkoxycarbonyl group, or a carboxyl group is mentioned.
When the polycyclic fused aromatic skeleton has a plurality of substituents, they may form a ring.

  Examples of the halogen atom include fluorine, chlorine, bromine and iodine.

A substituted or unsubstituted amino group is represented by —NX ¹ X ^2, and examples of X ¹ and X ² are independently a hydrogen atom, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, s-butyl group, isobutyl group, t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 2 -Hydroxyisobutyl group, 1,2-dihydroxyethyl group, 1,3-dihydroxyisopropyl group, 2,3-dihydroxy-t-butyl group, 1,2,3-trihydroxypropyl group, chloromethyl group, 1-chloroethyl Group, 2-chloroethyl group, 2-chloroisobutyl group, 1,2-dichloroethyl group, 1,3-dichloroisopropyl group, 2,3-dichloro-t-butyl group Group, 1,2,3-trichloropropyl group, bromomethyl group, 1-bromoethyl group, 2-bromoethyl group, 2-bromoisobutyl group, 1,2-dibromoethyl group, 1,3-dibromoisopropyl group, 2, 3-dibromo-t-butyl group, 1,2,3-tribromopropyl group, iodomethyl group, 1-iodoethyl group, 2-iodoethyl group, 2-iodoisobutyl group, 1,2-diiodoethyl group, 1,3- Diiodoisopropyl group, 2,3-diiodo-t-butyl group, 1,2,3-triiodopropyl group, aminomethyl group, 1-aminoethyl group, 2-aminoethyl group, 2-aminoisobutyl group, 1 , 2-diaminoethyl group, 1,3-diaminoisopropyl group, 2,3-diamino-t-butyl group, 1,2,3-triaminopropyl group, cyanomethyl 1-cyanoethyl group, 2-cyanoethyl group, 2-cyanoisobutyl group, 1,2-dicyanoethyl group, 1,3-dicyanoisopropyl group, 2,3-dicyano-t-butyl group, 1,2,3- Tricyanopropyl group, nitromethyl group, 1-nitroethyl group, 2-nitroethyl group, 2-nitroisobutyl group, 1,2-dinitroethyl group, 1,3-dinitroisopropyl group, 2,3-dinitro-t-butyl group 1,2,3-trinitropropyl group, phenyl group, 1-naphthyl group, 2-naphthyl group, 1-anthryl group, 2-anthryl group, 9-anthryl group, 1-phenanthryl group, 2-phenanthryl group, 3-phenanthryl group, 4-phenanthryl group, 9-phenanthryl group, 1-naphthacenyl group, 2-naphthacenyl group, 9-naphthacenyl group, 4- Styrylphenyl group, 1-pyrenyl group, 2-pyrenyl group, 4-pyrenyl group, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group, p-terphenyl-4-yl group, p-ter Phenyl-3-yl group, p-terphenyl-2-yl group, m-terphenyl-4-yl group, m-terphenyl-3-yl group, m-terphenyl-2-yl group, o-tolyl Group, m-tolyl group, p-tolyl group, pt-butylphenyl group, p- (2-phenylpropyl) phenyl group, 3-methyl-2-naphthyl group, 4-methyl-1-naphthyl group, 4 -Methyl-1-anthryl group, 4'-methylbiphenylyl group, 4 "-t-butyl-p-terphenyl-4-yl group, 2-pyrrolyl group, 3-pyrrolyl group, pyrazinyl group, 2-pyridinyl group , 3-pyridinyl group, 4-pyridinyl group, 2-indolyl group, 3-indolyl group, 4-indolyl group, 5-indolyl group, 6-indolyl group, 7-indolyl group, 1-isoindolyl group, 3-isoindolyl group, 4-isoindolyl group, 5-isoindolyl group, 6-isoindolyl group, 7-isoindolyl group, 2-furyl group, 3-furyl group, 2-benzofuranyl group, 3-benzofuranyl group, 4-benzofuranyl group, 5-benzofuranyl group, 6-benzofuranyl group, 7-benzofuranyl group, 1-isobenzofuranyl group, 3-isobenzofuranyl group, 4-isobenzofuranyl group, 5-isobenzofuranyl group, 6-isobenzofuranyl group, 7-isobenzofuran group Nyl, 2-quinolyl, 3-quinolyl, 4-quinolyl, 5-quinolyl, 6-quinolyl, 7-quinolyl 8-quinolyl group, 1-isoquinolyl group, 3-isoquinolyl group, 4-isoquinolyl group, 5-isoquinolyl group, 6-isoquinolyl group, 7-isoquinolyl group, 8-isoquinolyl group, 2-quinoxalinyl group, 5-quinoxalinyl group 6-quinoxalinyl group, 1-phenanthridinyl group, 2-phenanthridinyl group, 3-phenanthridinyl group, 4-phenanthridinyl group, 6-phenanthridinyl group, 7-phenanth Lysinyl group, 8-phenanthridinyl group, 9-phenanthridinyl group, 10-phenanthridinyl group, 1-acridinyl group, 2-acridinyl group, 3-acridinyl group, 4-acridinyl group, 9- Acridinyl group, 1,7-phenanthrolin-2-yl group, 1,7-phenanthrolin-3-yl group, 1,7-phenanthrolin-4 Yl group, 1,7-phenanthrolin-5-yl group, 1,7-phenanthrolin-6-yl group, 1,7-phenanthrolin-8-yl group, 1,7-phenanthrolin- 9-yl group, 1,7-phenanthrolin-10-yl group, 1,8-phenanthrolin-2-yl group, 1,8-phenanthrolin-3-yl group, 1,8-phenance Lorin-4-yl group, 1,8-phenanthrolin-5-yl group, 1,8-phenanthrolin-6-yl group, 1,8-phenanthrolin-7-yl group, 1,8- Phenanthrolin-9-yl group, 1,8-phenanthrolin-10-yl group, 1,9-phenanthrolin-2-yl group, 1,9-phenanthrolin-3-yl group, 1, 9-phenanthrolin-4-yl group, 1,9-phenanthrolin-5-yl group, 1,9- Phenanthrolin-6-yl group, 1,9-phenanthrolin-7-yl group, 1,9-phenanthrolin-8-yl group, 1,9-phenanthrolin-10-yl group, 1, 10-phenanthrolin-2-yl group, 1,10-phenanthrolin-3-yl group, 1,10-phenanthrolin-4-yl group, 1,10-phenanthrolin-5-yl group, 2,9-phenanthrolin-1-yl group, 2,9-phenanthrolin-3-yl group, 2,9-phenanthrolin-4-yl group, 2,9-phenanthrolin-5-yl Group, 2,9-phenanthroline-6-yl group, 2,9-phenanthrolin-7-yl group, 2,9-phenanthrolin-8-yl group, 2,9-phenanthroline-10 -Yl group, 2,8-phenanthrolin-1-yl group, 2,8-phenane Lorin-3-yl group, 2,8-phenanthrolin-4-yl group, 2,8-phenanthrolin-5-yl group, 2,8-phenanthrolin-6-yl group, 2,8- Phenanthrolin-7-yl group, 2,8-phenanthrolin-9-yl group, 2,8-phenanthrolin-10-yl group, 2,7-phenanthrolin-1-yl group, 2, 7-phenanthrolin-3-yl group, 2,7-phenanthrolin-4-yl group, 2,7-phenanthrolin-5-yl group, 2,7-phenanthrolin-6-yl group, 2,7-phenanthrolin-8-yl group, 2,7-phenanthrolin-9-yl group, 2,7-phenanthrolin-10-yl group, 1-phenazinyl group, 2-phenazinyl group, 1 -Phenothiazinyl group, 2-phenothiazinyl group, 3-phenothiazinyl group 4-phenothiazinyl group, 1-phenoxazinyl group, 2-phenoxazinyl group, 3-phenoxazinyl group, 4-phenoxazinyl group, 2-oxazolyl group, 4-oxazolyl group, 5-oxazolyl group, 2-oxadiazolyl group, 5-oxadiazolyl group Group, 3-furazanyl group, 2-thienyl group, 3-thienyl group, 2-methylpyrrol-1-yl group, 2-methylpyrrol-3-yl group, 2-methylpyrrol-4-yl group, 2-methyl Pyrrol-5-yl group, 3-methylpyrrol-1-yl group, 3-methylpyrrol-2-yl group, 3-methylpyrrol-4-yl group, 3-methylpyrrol-5-yl group, 2-t -Butylpyrrol-4-yl group, 3- (2-phenylpropyl) pyrrol-1-yl group, 2-methyl-1-indolyl group, 4-methyl-1 -Indolyl group, 2-methyl-3-indolyl group, 4-methyl-3-indolyl group, 2-t-butyl-1-indolyl group, 4-t-butyl-1-indolyl group, 2-t-butyl- A 3-indolyl group, 4-t-butyl-3-indolyl group, etc. are mentioned.

  Examples of substituted or unsubstituted alkyl groups include methyl, ethyl, propyl, isopropyl, n-butyl, s-butyl, isobutyl, t-butyl, n-pentyl, and n-hexyl. Group, n-heptyl group, n-octyl group, hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 2-hydroxyisobutyl group, 1,2-dihydroxyethyl group, 1,3-dihydroxyisopropyl group, 2,3-dihydroxy-t-butyl group, 1,2,3-trihydroxypropyl group, chloromethyl group, 1-chloroethyl group, 2-chloroethyl group, 2-chloroisobutyl group, 1,2-dichloroethyl group, 1,3-dichloroisopropyl group, 2,3-dichloro-t-butyl group, 1,2,3-trichloropropyl group, bromomethyl group, 1 Bromoethyl group, 2-bromoethyl group, 2-bromoisobutyl group, 1,2-dibromoethyl group, 1,3-dibromoisopropyl group, 2,3-dibromo-t-butyl group, 1,2,3-tribromopropyl Group, iodomethyl group, 1-iodoethyl group, 2-iodoethyl group, 2-iodoisobutyl group, 1,2-diiodoethyl group, 1,3-diiodoisopropyl group, 2,3-diiodo-t-butyl group, 1, 2,3-triiodopropyl group, aminomethyl group, 1-aminoethyl group, 2-aminoethyl group, 2-aminoisobutyl group, 1,2-diaminoethyl group, 1,3-diaminoisopropyl group, 2,3 -Diamino-t-butyl group, 1,2,3-triaminopropyl group, cyanomethyl group, 1-cyanoethyl group, 2-cyanoethyl group, 2-cyanoisobutyl Group, 1,2-dicyanoethyl group, 1,3-dicyanoisopropyl group, 2,3-dicyano-t-butyl group, 1,2,3-tricyanopropyl group, nitromethyl group, 1-nitroethyl group, 2 -Nitroethyl group, 2-nitroisobutyl group, 1,2-dinitroethyl group, 1,3-dinitroisopropyl group, 2,3-dinitro-t-butyl group, 1,2,3-trinitropropyl group, etc. It is done.

  Examples of substituted or unsubstituted alkenyl groups include vinyl, allyl, 1-butenyl, 2-butenyl, 3-butenyl, 1,3-butanedienyl, 1-methylvinyl, styryl, 4 -Diphenylaminostyryl group, 4-di-p-tolylaminostyryl group, 4-di-m-tolylaminostyryl group, 2,2-diphenylvinyl group, 1,2-diphenylvinyl group, 1-methylallyl group, 1 , 1-dimethylallyl group, 2-methylallyl group, 1-phenylallyl group, 2-phenylallyl group, 3-phenylallyl group, 3,3-diphenylallyl group, 1,2-dimethylallyl group, 1-phenyl- Examples include 1-butenyl group and 3-phenyl-1-butenyl group.

  Examples of the substituted or unsubstituted cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a 4-methylcyclohexyl group, and the like.

  The substituted or unsubstituted alkoxy group is a group represented by -OY, and examples of Y include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group, t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 2-hydroxyisobutyl group, 1,2 -Dihydroxyethyl group, 1,3-dihydroxyisopropyl group, 2,3-dihydroxy-t-butyl group, 1,2,3-trihydroxypropyl group, chloromethyl group, 1-chloroethyl group, 2-chloroethyl group, 2 -Chloroisobutyl group, 1,2-dichloroethyl group, 1,3-dichloroisopropyl group, 2,3-dichloro-t-butyl group, 1,2,3-trick Ropropyl group, bromomethyl group, 1-bromoethyl group, 2-bromoethyl group, 2-bromoisobutyl group, 1,2-dibromoethyl group, 1,3-dibromoisopropyl group, 2,3-dibromo-t-butyl group, 1 , 2,3-tribromopropyl group, iodomethyl group, 1-iodoethyl group, 2-iodoethyl group, 2-iodoisobutyl group, 1,2-diiodoethyl group, 1,3-diiodoisopropyl group, 2,3-diiodo -T-butyl group, 1,2,3-triiodopropyl group, aminomethyl group, 1-aminoethyl group, 2-aminoethyl group, 2-aminoisobutyl group, 1,2-diaminoethyl group, 1,3 -Diaminoisopropyl group, 2,3-diamino-t-butyl group, 1,2,3-triaminopropyl group, cyanomethyl group, 1-cyanoethyl group, 2 Cyanoethyl group, 2-cyanoisobutyl group, 1,2-dicyanoethyl group, 1,3-dicyanoisopropyl group, 2,3-dicyano-t-butyl group, 1,2,3-tricyanopropyl group, nitromethyl group, 1-nitroethyl group, 2-nitroethyl group, 2-nitroisobutyl group, 1,2-dinitroethyl group, 1,3-dinitroisopropyl group, 2,3-dinitro-t-butyl group, 1,2,3-tri Examples thereof include a nitropropyl group.

  Examples of the substituted or unsubstituted aromatic hydrocarbon group include phenyl group, 1-naphthyl group, 2-naphthyl group, 1-anthryl group, 2-anthryl group, 9-anthryl group, 1-phenanthryl group, 2- Phenanthryl group, 3-phenanthryl group, 4-phenanthryl group, 9-phenanthryl group, 1-naphthacenyl group, 2-naphthacenyl group, 9-naphthacenyl group, 1-pyrenyl group, 2-pyrenyl group, 4-pyrenyl group, 2- Biphenylyl group, 3-biphenylyl group, 4-biphenylyl group, p-terphenyl-4-yl group, p-terphenyl-3-yl group, p-terphenyl-2-yl group, m-terphenyl -4-yl group, m-terphenyl-3-yl group, m-terphenyl-2-yl group, o-tolyl group, m-tolyl group, p-tolyl group, pt-butyl group Nyl group, p- (2-phenylpropyl) phenyl group, 3-methyl-2-naphthyl group, 4-methyl-1-naphthyl group, 4-methyl-1-anthryl group, 4′-methylbiphenylyl group, 4 "-T-butyl-p-terphenyl-4-yl group and the like.

  Examples of the substituted or unsubstituted aromatic heterocyclic group include 1-pyrrolyl group, 2-pyrrolyl group, 3-pyrrolyl group, pyrazinyl group, 2-pyridinyl group, 3-pyridinyl group, 4-pyridinyl group, 1-pyrrolyl group, Indolyl group, 2-indolyl group, 3-indolyl group, 4-indolyl group, 5-indolyl group, 6-indolyl group, 7-indolyl group, 1-isoindolyl group, 2-isoindolyl group, 3-isoindolyl group, 4- Isoindolyl group, 5-isoindolyl group, 6-isoindolyl group, 7-isoindolyl group, 2-furyl group, 3-furyl group, 2-benzofuranyl group, 3-benzofuranyl group, 4-benzofuranyl group, 5-benzofuranyl group, 6- Benzofuranyl group, 7-benzofuranyl group, 1-isobenzofuranyl group, 3-isobenzofuranyl group, 4-isobenzo Ranyl group, 5-isobenzofuranyl group, 6-isobenzofuranyl group, 7-isobenzofuranyl group, 2-quinolyl group, 3-quinolyl group, 4-quinolyl group, 5-quinolyl group, 6-quinolyl Group, 7-quinolyl group, 8-quinolyl group, 1-isoquinolyl group, 3-isoquinolyl group, 4-isoquinolyl group, 5-isoquinolyl group, 6-isoquinolyl group, 7-isoquinolyl group, 8-isoquinolyl group, 2-quinoxalinyl Group, 5-quinoxalinyl group, 6-quinoxalinyl group, 1-phenanthridinyl group, 2-phenanthridinyl group, 3-phenanthridinyl group, 4-phenanthridinyl group, 6-phenanthridinyl group Group, 7-phenanthridinyl group, 8-phenanthridinyl group, 9-phenanthridinyl group, 10-phenanthridinyl group, 1-acridinyl group, 2 Acridinyl group, 3-acridinyl group, 4-acridinyl group, 9-acridinyl group, 1,7-phenanthrolin-2-yl group, 1,7-phenanthrolin-3-yl group, 1,7-phenance Lorin-4-yl group, 1,7-phenanthrolin-5-yl group, 1,7-phenanthrolin-6-yl group, 1,7-phenanthrolin-8-yl group, 1,7- Phenanthrolin-9-yl group, 1,7-phenanthrolin-10-yl group, 1,8-phenanthrolin-2-yl group, 1,8-phenanthrolin-3-yl group, 1, 8-phenanthroline-4-yl group, 1,8-phenanthrolin-5-yl group, 1,8-phenanthrolin-6-yl group, 1,8-phenanthrolin-7-yl group, 1,8-phenanthrolin-9-yl group, 1,8-phenanth Lorin-10-yl group, 1,9-phenanthrolin-2-yl group, 1,9-phenanthrolin-3-yl group, 1,9-phenanthrolin-4-yl group, 1,9- Phenanthrolin-5-yl group, 1,9-phenanthrolin-6-yl group, 1,9-phenanthrolin-7-yl group, 1,9-phenanthrolin-8-yl group, 1, 9-phenanthrolin-10-yl group, 1,10-phenanthrolin-2-yl group, 1,10-phenanthrolin-3-yl group, 1,10-phenanthrolin-4-yl group, 1,10-phenanthrolin-5-yl group, 2,9-phenanthrolin-1-yl group, 2,9-phenanthrolin-3-yl group, 2,9-phenanthrolin-4-yl Group, 2,9-phenanthrolin-5-yl group, 2,9-phenanthroline- -Yl group, 2,9-phenanthrolin-7-yl group, 2,9-phenanthrolin-8-yl group, 2,9-phenanthrolin-10-yl group, 2,8-phenanthroline -1-yl group, 2,8-phenanthrolin-3-yl group, 2,8-phenanthrolin-4-yl group, 2,8-phenanthrolin-5-yl group, 2,8-phen group Nansulolin-6-yl group, 2,8-phenanthrolin-7-yl group, 2,8-phenanthrolin-9-yl group, 2,8-phenanthrolin-10-yl group, 2,7 -Phenanthrolin-1-yl group, 2,7-phenanthrolin-3-yl group, 2,7-phenanthrolin-4-yl group, 2,7-phenanthrolin-5-yl group, 2 , 7-phenanthrolin-6-yl group, 2,7-phenanthrolin-8-yl group, 2, -Phenanthrolin-9-yl group, 2,7-phenanthrolin-10-yl group, 1-phenazinyl group, 2-phenazinyl group, 1-phenothiazinyl group, 2-phenothiazinyl group, 3-phenothiazinyl group 4-phenothiazinyl group, 10-phenothiazinyl group, 1-phenoxazinyl group, 2-phenoxazinyl group, 3-phenoxazinyl group, 4-phenoxazinyl group, 10-phenoxazinyl group, 2-oxazolyl group, 4-oxazolyl group, 5- Oxazolyl group, 2-oxadiazolyl group, 5-oxadiazolyl group, 3-furazanyl group, 2-thienyl group, 3-thienyl group, 2-methylpyrrol-1-yl group, 2-methylpyrrol-3-yl group, 2- Methylpyrrol-4-yl group, 2-methylpyrrol-5-yl group, 3-methylpyrrol-1- Yl group, 3-methylpyrrol-2-yl group, 3-methylpyrrol-4-yl group, 3-methylpyrrol-5-yl group, 2-t-butylpyrrol-4-yl group, 3- (2- Phenylpropyl) pyrrol-1-yl group, 2-methyl-1-indolyl group, 4-methyl-1-indolyl group, 2-methyl-3-indolyl group, 4-methyl-3-indolyl group, 2-t- Examples thereof include a butyl-1-indolyl group, a 4-t-butyl-1-indolyl group, a 2-t-butyl-3-indolyl group, and a 4-t-butyl-3-indolyl group.

  Examples of substituted or unsubstituted aralkyl groups include benzyl, 1-phenylethyl, 2-phenylethyl, 1-phenylisopropyl, 2-phenylisopropyl, phenyl-t-butyl, α-naphthylmethyl. Group, 1-α-naphthylethyl group, 2-α-naphthylethyl group, 1-α-naphthylisopropyl group, 2-α-naphthylisopropyl group, β-naphthylmethyl group, 1-β-naphthylethyl group, 2- β-naphthylethyl group, 1-β-naphthylisopropyl group, 2-β-naphthylisopropyl group, 1-pyrrolylmethyl group, 2- (1-pyrrolyl) ethyl group, p-methylbenzyl group, m-methylbenzyl group, o -Methylbenzyl group, p-chlorobenzyl group, m-chlorobenzyl group, o-chlorobenzyl group, p-bromobenzyl group, m-bromobe Gil group, o-bromobenzyl group, p-iodobenzyl group, m-iodobenzyl group, o-iodobenzyl group, p-hydroxybenzyl group, m-hydroxybenzyl group, o-hydroxybenzyl group, p-aminobenzyl group M-aminobenzyl group, o-aminobenzyl group, p-nitrobenzyl group, m-nitrobenzyl group, o-nitrobenzyl group, p-cyanobenzyl group, m-cyanobenzyl group, o-cyanobenzyl group, 1 -Hydroxy-2-phenylisopropyl group, 1-chloro-2-phenylisopropyl group and the like.

  A substituted or unsubstituted aryloxy group is represented by —OZ, and examples of Z include a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 1-anthryl group, a 2-anthryl group, a 9-anthryl group, 1 -Phenanthryl group, 2-phenanthryl group, 3-phenanthryl group, 4-phenanthryl group, 9-phenanthryl group, 1-naphthacenyl group, 2-naphthacenyl group, 9-naphthacenyl group, 1-pyrenyl group, 2-pyrenyl group, 4 -Pyrenyl group, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group, p-terphenyl-4-yl group, p-terphenyl-3-yl group, p-terphenyl-2-yl Group, m-terphenyl-4-yl group, m-terphenyl-3-yl group, m-terphenyl-2-yl group, o-tolyl group, m-tolyl group, p-tolyl group , Pt-butylphenyl group, p- (2-phenylpropyl) phenyl group, 3-methyl-2-naphthyl group, 4-methyl-1-naphthyl group, 4-methyl-1-anthryl group, 4′- Methylbiphenylyl group, 4 ″ -t-butyl-p-terphenyl-4-yl group, 2-pyrrolyl group, 3-pyrrolyl group, pyrazinyl group, 2-pyridinyl group, 3-pyridinyl group, 4-pyridinyl group, 2-indolyl group, 3-indolyl group, 4-indolyl group, 5-indolyl group, 6-indolyl group, 7-indolyl group, 1-isoindolyl group, 3-isoindolyl group, 4-isoindolyl group, 5-isoindolyl group, 6-isoindolyl group, 7-isoindolyl group, 2-furyl group, 3-furyl group, 2-benzofuranyl group, 3-benzofuranyl group, 4-benzofuranyl group 5-benzofuranyl group, 6-benzofuranyl group, 7-benzofuranyl group, 1-isobenzofuranyl group, 3-isobenzofuranyl group, 4-isobenzofuranyl group, 5-isobenzofuranyl group, 6-iso Benzofuranyl group, 7-isobenzofuranyl group, 2-quinolyl group, 3-quinolyl group, 4-quinolyl group, 5-quinolyl group, 6-quinolyl group, 7-quinolyl group, 8-quinolyl group, 1- Isoquinolyl group, 3-isoquinolyl group, 4-isoquinolyl group, 5-isoquinolyl group, 6-isoquinolyl group, 7-isoquinolyl group, 8-isoquinolyl group, 2-quinoxalinyl group, 5-quinoxalinyl group, 6-quinoxalinyl group, 1- Phenanthridinyl group, 2-phenanthridinyl group, 3-phenanthridinyl group, 4-phenanthridinyl group, 6-phenanthridinyl group Group, 7-phenanthridinyl group, 8-phenanthridinyl group, 9-phenanthridinyl group, 10-phenanthridinyl group, 1-acridinyl group, 2-acridinyl group, 3-acridinyl group, 4 -Acridinyl group, 9-acridinyl group, 1,7-phenanthrolin-2-yl group, 1,7-phenanthrolin-3-yl group, 1,7-phenanthrolin-4-yl group, 1, 7-phenanthrolin-5-yl group, 1,7-phenanthrolin-6-yl group, 1,7-phenanthrolin-8-yl group, 1,7-phenanthrolin-9-yl group, 1,7-phenanthrolin-10-yl group, 1,8-phenanthrolin-2-yl group, 1,8-phenanthrolin-3-yl group, 1,8-phenanthrolin-4-yl Group, 1,8-phenanthrolin-5-yl group 1,8-phenanthroline-6-yl group, 1,8-phenanthrolin-7-yl group, 1,8-phenanthrolin-9-yl group, 1,8-phenanthrolin-10-yl Group, 1,9-phenanthrolin-2-yl group, 1,9-phenanthrolin-3-yl group, 1,9-phenanthrolin-4-yl group, 1,9-phenanthrolin-5 -Yl group, 1,9-phenanthroline-6-yl group, 1,9-phenanthrolin-7-yl group, 1,9-phenanthrolin-8-yl group, 1,9-phenanthroline -10-yl group, 1,10-phenanthrolin-2-yl group, 1,10-phenanthrolin-3-yl group, 1,10-phenanthrolin-4-yl group, 1,10-phen group Nansulolin-5-yl group, 2,9-phenanthrolin-1-yl group, 2,9 Phenanthrolin-3-yl group, 2,9-phenanthrolin-4-yl group, 2,9-phenanthrolin-5-yl group, 2,9-phenanthrolin-6-yl group, 2, 9-phenanthroline-7-yl group, 2,9-phenanthrolin-8-yl group, 2,9-phenanthrolin-10-yl group, 2,8-phenanthrolin-1-yl group, 2,8-phenanthrolin-3-yl group, 2,8-phenanthrolin-4-yl group, 2,8-phenanthrolin-5-yl group, 2,8-phenanthrolin-6-yl group Group, 2,8-phenanthroline-7-yl group, 2,8-phenanthrolin-9-yl group, 2,8-phenanthrolin-10-yl group, 2,7-phenanthroline-1 -Yl group, 2,7-phenanthroline-3-yl group, 2,7-phenanthroline -4-yl group, 2,7-phenanthrolin-5-yl group, 2,7-phenanthrolin-6-yl group, 2,7-phenanthrolin-8-yl group, 2,7-phen group Nanthrolin-9-yl group, 2,7-phenanthrolin-10-yl group, 1-phenazinyl group, 2-phenazinyl group, 1-phenothiazinyl group, 2-phenothiazinyl group, 3-phenothiazinyl group, 4 -Phenothiazinyl group, 1-phenoxazinyl group, 2-phenoxazinyl group, 3-phenoxazinyl group, 4-phenoxazinyl group, 2-oxazolyl group, 4-oxazolyl group, 5-oxazolyl group, 2-oxadiazolyl group, 5-oxadiazolyl group, 3-flazanyl group, 2-thienyl group, 3-thienyl group, 2-methylpyrrol-1-yl group, 2-methylpyrrol-3-yl group, 2-methyl group Rupyrrol-4-yl group, 2-methylpyrrol-5-yl group, 3-methylpyrrol-1-yl group, 3-methylpyrrol-2-yl group, 3-methylpyrrol-4-yl group, 3-methyl Pyrrol-5-yl group, 2-t-butylpyrrol-4-yl group, 3- (2-phenylpropyl) pyrrol-1-yl group, 2-methyl-1-indolyl group, 4-methyl-1-indolyl group Group, 2-methyl-3-indolyl group, 4-methyl-3-indolyl group, 2-t-butyl-1-indolyl group, 4-t-butyl-1-indolyl group, 2-t-butyl-3- Indolyl group, 4-t-butyl-3-indolyl group and the like can be mentioned.

  A substituted or unsubstituted alkoxycarbonyl group is represented as —COOY, and examples of Y include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group, t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 2-hydroxyisobutyl group, 1,2-dihydroxyethyl group, 1,3-dihydroxyisopropyl group, 2,3-dihydroxy-t-butyl group, 1,2,3-trihydroxypropyl group, chloromethyl group, 1-chloroethyl group, 2-chloroethyl group, 2-chloroisobutyl group, 1,2-dichloroethyl group, 1,3-dichloroisopropyl group, 2,3-dichloro-t-butyl group, 1,2,3-trimethyl Ropropyl group, bromomethyl group, 1-bromoethyl group, 2-bromoethyl group, 2-bromoisobutyl group, 1,2-dibromoethyl group, 1,3-dibromoisopropyl group, 2,3-dibromo-t-butyl group, 1 , 2,3-tribromopropyl group, iodomethyl group, 1-iodoethyl group, 2-iodoethyl group, 2-iodoisobutyl group, 1,2-diiodoethyl group, 1,3-diiodoisopropyl group, 2,3-diiodo -T-butyl group, 1,2,3-triiodopropyl group, aminomethyl group, 1-aminoethyl group, 2-aminoethyl group, 2-aminoisobutyl group, 1,2-diaminoethyl group, 1,3 -Diaminoisopropyl group, 2,3-diamino-t-butyl group, 1,2,3-triaminopropyl group, cyanomethyl group, 1-cyanoethyl group, 2 Cyanoethyl group, 2-cyanoisobutyl group, 1,2-dicyanoethyl group, 1,3-dicyanoisopropyl group, 2,3-dicyano-t-butyl group, 1,2,3-tricyanopropyl group, nitromethyl group, 1-nitroethyl group, 2-nitroethyl group, 2-nitroisobutyl group, 1,2-dinitroethyl group, 1,3-dinitroisopropyl group, 2,3-dinitro-t-butyl group, 1,2,3-tri Examples thereof include a nitropropyl group.

In the present invention, the polycyclic fused aromatic skeleton has a substituent, and the substituent is a substituted or unsubstituted aryl group or heteroaryl group (excluding those having a carbazole skeleton). It is preferable.
By introducing an aryl group or heteroaryl group as a substituent, it is possible to extend the life by adjusting the energy gap or preventing molecular association.
Here, when a carbazole group is introduced as a substituent, the triplet energy gap becomes wide due to an increase in ionization potential and the like, so that it can be applied as a host to phosphorescent dopants with shorter wavelengths. The introduction of a group is not preferable because it leads to a shortened life.
In this respect, in the present invention, the carbazole group can be removed from the substituent, and the lifetime can be extended although the energy gap is narrowed.

In the present invention, the polycyclic fused aromatic skeleton is substituted or unsubstituted click Risenjiiru, is preferably selected from the group of fluoranthene diisopropyl Le.
The polycyclic fused aromatic skeleton is preferably substituted with a group having phenanthrene, chrysene, fluoranthene, or triphenylene.

  In the present invention, the polycyclic fused aromatic skeleton is preferably represented by any one of the following formulas (2) to (4).

In the formulas (2) to (4), Ar ^{1 to} Ar ⁴ represent a substituted or unsubstituted condensed ring structure having 4 to 10 nuclear carbon atoms.

Examples of the compound represented by the formula (2) include substituted or unsubstituted phenanthrene and chrysene.
Examples of the compound represented by the formula (3) include substituted or unsubstituted acenaphthylene, acenaphthene, fluoranthene, and the like.
Examples of the compound represented by the formula (4) include substituted or unsubstituted benzofluoranthene.

  In the present invention, the polycyclic fused aromatic skeleton is preferably a simple substance or a derivative of phenanthrene represented by the following formula (50).

Examples of the substituent of the phenanthrene derivative include alkyl group, cycloalkyl group, aralkyl group, alkenyl group, cycloalkenyl group, alkynyl group, hydroxyl group, mercapto group, alkoxy group, alkylthio group, aryl ether group, aryl thioether group, aryl Group, heterocyclic group, halogen, haloalkane, haloalkene, haloalkyne, cyano group, aldehyde group, carbonyl group, carboxyl group, ester group, amino group, nitro group, silyl group, and siloxanyl group.
Examples of such phenanthrene derivatives include the following.

  In the present invention, the polycyclic fused aromatic skeleton is preferably a simple substance or a derivative of chrysene represented by the following formula (51).

  As a chrysene derivative, the following are mentioned, for example.

  In the present invention, the polycyclic fused aromatic skeleton is preferably a simple substance or a derivative of a compound (benzo [c] phenanthrene) represented by the following formula (52).

  Examples of derivatives of such compounds include the following.

  In the present invention, the polycyclic fused aromatic skeleton is preferably a simple substance or a derivative of a compound (benzo [c] chrysene) represented by the following formula (53).

  Examples of derivatives of such compounds include the following.

  In the present invention, the polycyclic fused aromatic skeleton is preferably a simple substance or a derivative of a compound represented by the following formula (54) (dibenzo [c, g] phenanthrene).

  Examples of derivatives of such compounds include the following.

  In the present invention, the polycyclic fused aromatic skeleton is preferably a simple substance or a derivative of fluoranthene represented by the following formula (55).

  As a fluoranthene derivative, the following are mentioned, for example.

  Examples of the substituted or unsubstituted benzofluoranthene include, for example, a simple substance or derivative of benzo [b] fluoranthene represented by the following formula (551), a simple substance of benzo [k] fluoranthene represented by the formula (552), or Derivatives.

In formula (551) and formula (552), X ^{1 to} X ²⁴ are a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group, a linear, branched or cyclic alkoxy group, or substituted or unsubstituted aryl. Represents a group.
The aryl group represents a carbocyclic aromatic group such as a phenyl group or a naphthyl group, for example, a heterocyclic aromatic group such as a furyl group, a thienyl group, or a pyridyl group.

X ^{1 to} X ²⁴ are preferably a hydrogen atom, a halogen atom (eg, fluorine atom, chlorine atom, bromine atom), a linear, branched or cyclic alkyl group having 1 to 16 carbon atoms (eg, methyl group, ethyl group). Group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, tert-pentyl group, cyclopentyl group, n-hexyl Group, 3,3-dimethylbutyl group, cyclohexyl group, n-heptyl group, cyclohexylmethyl group, n-octyl group, tert-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group, n-dodecyl Group, n-tetradecyl group, n-hexadecyl group, etc.), linear, branched or cyclic alkoxy group having 1 to 16 carbon atoms (for example, methoxy group, ethoxy group, etc.) Group, n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, sec-butoxy group, n-pentyloxy group, neopentyloxy group, cyclopentyloxy group, n-hexyloxy group, 3,3-dimethyl Butyloxy group, cyclohexyloxy group, n-heptyloxy group, n-octyloxy group, 2-ethylhexyloxy group, n-nonyloxy group, n-decyloxy group, n-dodecyloxy group, n-tetradecyloxy group, n -Hexadecyloxy group, etc., or a substituted or unsubstituted aryl group having 4 to 16 carbon atoms (for example, phenyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl) Group, 4-n-propylphenyl group, 4-isopropylphenyl group, 4-n-butylpheny Group, 4-tert-butylphenyl group, 4-isopentylphenyl group, 4-tert-pentylphenyl group, 4-n-hexylphenyl group, 4-cyclohexylphenyl group, 4-n-octylphenyl group, 4-n -Decylphenyl group, 2,3-dimethylphenyl group, 2,4-dimethylphenyl group, 2,5-dimethylphenyl group, 3,4-dimethylphenyl group, 5-indanyl group, 1,2,3,4- Tetrahydro-5-naphthyl group, 1,2,3,4-tetrahydro-6-naphthyl group, 2-methoxyphenyl group, 3-methoxyphenyl group, 4-methoxyphenyl group, 3-ethoxyphenyl group, 4-ethoxyphenyl Group, 4-n-propoxyphenyl group, 4-isopropoxyphenyl group, 4-n-butoxyphenyl group, 4-n-pentyloxyphenyl group, 4 -N-hexyloxyphenyl group, 4-cyclohexyloxyphenyl group, 4-n-heptyloxyphenyl group, 4-n-octyloxyphenyl group, 4-n-decyloxyphenyl group, 2,3-dimethoxyphenyl group, 2,5-dimethoxyphenyl group, 3,4-dimethoxyphenyl group, 2-methoxy-5-methylphenyl group, 3-methyl-4-methoxyphenyl group, 2-fluorophenyl group, 3-fluorophenyl group, 4- Fluorophenyl group, 2-chlorophenyl group, 3-chlorophenyl group, 4-chlorophenyl group, 4-bromophenyl group, 4-trifluoromethylphenyl group, 3,4-dichlorophenyl group, 2-methyl-4-chlorophenyl group, 2 -Chloro-4-methylphenyl group, 3-chloro-4-methylphenyl group, 2-chloro- -Methoxyphenyl group, 4-phenylphenyl group, 3-phenylphenyl group, 4- (4'-methylphenyl) phenyl group, 4- (4'-methoxyphenyl) phenyl group, 1-naphthyl group, 2-naphthyl group 4-ethoxy-1-naphthyl group, 6-methoxy-2-naphthyl group, 7-ethoxy-2-naphthyl group, 2-furyl group, 2-thienyl group, 3-thienyl group, 2-pyridyl group, 3- And more preferably a hydrogen atom, a fluorine atom, a chlorine atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an aryl having 6 to 12 carbon atoms. More preferably a hydrogen atom, a fluorine atom, a chlorine atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a carbocyclic aromatic group having 6 to 10 carbon atoms. The

  Examples of the benzo [b] fluoranthene derivative represented by the formula (551) include the following.

  Examples of the benzo [k] fluoranthene derivative represented by the formula (552) include the following.

  In the present invention, the polycyclic fused aromatic skeleton is preferably a simple substance or a derivative of triphenylene represented by the following formula (56).

  As a triphenylene derivative, the following are mentioned, for example.

  The polycyclic fused aromatic skeleton may contain a nitrogen atom, and for example, the following may be used.

  In the present invention, the ligand represented by the formula (1) is preferably represented by the following formula (5).

In formula (5),
R ₄ ′, R ₅ ′, and R ₆ ′ are each independently H, alkyl, alkenyl, alkynyl, heteroalkyl, alkenyl, alkynyl, heteroalkyl, aryl, heteroaryl, aralkyl; R ₄ ′, R ₅ ′, and R ₆ ′ may be optionally substituted with one or more substituents Z;
In addition or alternatively, any one or more of R ₄ ′ and R ₅ ′, or R ₅ ′ and R ₆ ′, or R ₃ and R ₄ are taken together to form an independently fused 4-7 membered cyclic group Wherein the cyclic group is cycloalkyl, cycloheteroalkyl, aryl, or heteroaryl; the cyclic group may be optionally substituted with one or more substituents Z;
Additionally or alternatively, _{R 3} 'and _{R 6} have the _{formula: -CR 2 -CR 2 -, -} CR = CR -, - CR 2 -, - O -, - NR -, - O-CR 2 -, Linked by a group having —NR—CR ₂ —, —N═CR—, R is selected from the group consisting of H, alkyl, aryl, and aralkyl.

  In the present invention, the ligand represented by the formula (5) is preferably represented by the following formula (6).

  In the present invention, the ligand represented by the formula (5) is preferably represented by the following formula (7).

  In the present invention, the ligand represented by the formula (5) is preferably represented by the following formula (8).

In the present invention, in the formula (5), R ₅ is preferably substituted or unsubstituted phenyl, naphthyl or pyridyl.
In particular, R ₅ is preferably phenyl.

In the present invention, in the formula (5), R ₃ ′ is preferably a methyl group.

  In the present invention, the ligand represented by the formula (5) is preferably represented by the following formula (9).

In formula (9), R ₅ ′ and R ₆ ′ are H, and in addition or alternatively, together form a fused 4-7 membered cyclic group, said cyclic group being cycloalkyl, Cycloheteroalkyl, aryl, or heteroaryl.

  In the present invention, the ligand represented by the formula (9) is preferably represented by the following formula (10).

  In the present invention, the ligand represented by the formula (10) is preferably represented by the following formula (11).

  In the present invention, the ligand represented by the formula (9) is preferably represented by the following formula (12).

  In the present invention, the ligand represented by the formula (12) is preferably represented by the following formula (13).

  In the present invention, the phosphorescent dopant is preferably represented by the following formula (14).

In the formula (14), M is a metal having an atomic weight of more than 40,
R ₃ ′ is a substituent selected from the group consisting of alkyl, heteroalkyl, aryl, heteroaryl, and aralkyl, and R ₃ ′ may be optionally substituted with one or more substituents Z;
R ₅ is a substituent selected from the group consisting of aryl and heteroaryl, said aryl or heteroaryl being unsubstituted or optionally substituted with one or more non-aromatic groups;
Ring A is an aromatic heterocyclic ring or a condensed aromatic heterocyclic ring having at least one nitrogen atom coordinated to the metal M, and ring A is optionally selected by one or more non-aromatic groups. Can be replaced by selection,
R ₃ is H, alkyl, alkenyl, alkynyl, alkylaryl, CN, CF ₃ , CnF _{2n + 1} , trifluorovinyl, CO ₂ R, C (O) R, NR ₂ , NO ₂ , OR, halo, aryl, hetero A substituent selected from the group consisting of aryl, substituted aryl, substituted heteroaryl or heterocyclic group;
R ₄ is H, alkyl, alkenyl, alkynyl, alkylaryl, CN, CF ₃ , CnF _{2n + 1} , trifluorovinyl, CO ₂ R, C (O) R, NR ₂ , NO ₂ , OR, halo, aryl, hetero A substituent selected from the group consisting of aryl, substituted aryl, substituted heteroaryl or heterocyclic group;
In addition or alternatively, R ₃ and R ₄ are taken together to independently form a fused 4-7 membered cyclic group, which can be cycloalkyl, cycloheteroalkyl, aryl, or heteroaryl And the cyclic group may be optionally substituted with one or more substituents Z,
R ₆ is H, alkyl, alkenyl, alkynyl, alkylaryl, CN, CF ₃ , CnF _{2n + 1} , trifluorovinyl, CO ₂ R, C (O) R, NR ₂ , NO ₂ , OR, halo, aryl, hetero A substituent selected from the group consisting of aryl, substituted aryl, substituted heteroaryl or heterocyclic group;
Alternatively, _{R 3} 'and _{R 6, -CR 2 -CR 2 -, -} CR = CR -, - CR 2 -, - O -, - NR -, - O-CR 2 -, - NR-CR 2 - And may be cross-linked by a group selected from -N = CR-
Each R is independently H, alkyl, alkenyl, alkynyl, heteroalkyl, aryl, heteroaryl, or aralkyl, wherein R is optionally substituted by one or more substituents Z;
Each Z is independently halogen, R ′, OR ′, N (R ′) ₂ , SR ′, C (O) R ′, C (O) OR ′, C (O) N (R ′) ₂ , CN, NO ₂ , SO ₂ , SOR ′, SO ₂ R ′, or SO ₃ R ′,
Each R ′ is independently H, alkyl, perhaloalkyl, alkenyl, alkynyl, heteroalkyl, aryl, or heteroaryl;
(XY) is an auxiliary ligand,
m is a value from 1 to the maximum number of ligands that can bind to the metal;
m + n is the maximum number of ligands that can bind to the metal.

Examples of each functional group include those similar to those exemplified in the above formula (1).
m (number of photoactive ligands of a particular type) can be any integer from 1 to the maximum number of ligands that can bind to the metal. For example, for Ir, m can be 1, 2 or 3. n (the number of “auxiliary” ligands of a particular type) can be any integer from 0 to an integer less than the maximum number of ligands that can bind to the metal. (X—Y) represents an auxiliary ligand. These ligands are called “auxiliary” because they are believed to be able to alter the photoactive properties of the molecule rather than directly contributing to the photoactive properties. The definitions of photoactivity and auxiliary are for non-limiting theory. For example, in the case of Ir, n may be 0, 1 or 2 for a bidentate ligand. The auxiliary ligand used in the luminescent material can be selected from those known in the art. Non-limiting examples of auxiliary ligands are described on pages 89-90 of Lamansky et al., PCT application WO 02/15645 A1, incorporated by reference. Preferred auxiliary ligands include acetylacetonate (acac) and picolinate (pic), and derivatives thereof. Preferred auxiliary ligands have the following structure:

  Preferably, ring A of the photoactive ligand is pyridine and has the following formula:

  And the following formula:

  Gives the light-emitting partial structure.

  In the present invention, the compound represented by the formula (14) is preferably represented by the following formula (15).

In formula (15),
R ₄ ′, R ₅ ′, and R ₆ ′ are each independently H, alkyl, alkenyl, alkynyl, heteroalkyl, alkenyl, alkynyl, heteroalkyl, aryl, heteroaryl, aralkyl; R ₄ ′, R ₅ ′, and R ₆ ′ may be optionally substituted with one or more substituents Z;
In addition or alternatively, any one or more of R ₄ ′ and R ₅ ′, or R ₅ ′ and R ₆ ′, or R ₃ and R ₄ are taken together to form an independently fused 4-7 membered cyclic group Wherein the cyclic group is cycloalkyl, cycloheteroalkyl, aryl, or heteroaryl; the cyclic group may be optionally substituted with one or more substituents Z;
Additionally or alternatively, _{R 3} 'and _{R 6} have the _{formula: -CR 2 -CR 2 -, -} CR = CR -, - CR 2 -, - O -, - NR -, - O-CR 2 -, Linked by a group having —NR—CR ₂ —, —N═CR—, R is selected from the group consisting of H, alkyl, aryl, and aralkyl.

  In the present invention, the compound represented by the formula (15) is preferably represented by the following formula (16).

  In the present invention, the compound represented by the formula (15) is preferably represented by the following formula (17).

  In the present invention, the compound represented by the formula (15) is preferably represented by the following formula (18).

In the present invention, in the formula (15), R ₅ is preferably substituted or unsubstituted phenyl, naphthyl or pyridyl.
In particular, R ₅ is preferably phenyl.

In the present invention, in the formula (15), R ₃ ′ is preferably a methyl group.

  In the present invention, the compound represented by the formula (15) is preferably represented by the following formula (19).

In formula (19), R ₅ ′ and R ₆ ′ are H, and in addition or alternatively, together form a fused 4-7 membered cyclic group, said cyclic group being cycloalkyl, Cycloheteroalkyl, aryl, or heteroaryl.

In the present invention, in the formula (19), M is selected from the group consisting of Ir, Pt, Pd, Rh, Re, Ru, Os, Tl, Pb, Bi, In, Sn, Sb, Te, Au, and Ag. It is preferred that
In particular, M is preferably Ir.

  In the present invention, the compound represented by the formula (19) is preferably represented by the following formula (20).

  In the present invention, the compound represented by the formula (20) is preferably represented by the following formula (21).

In the present invention, in the formula (21), m is preferably 3, and n is preferably 0.
In the present invention, in the formula (21), m may be 2 and n may be 1.
For example, for Ir, m is 3 and the structure may be referred to as a “tris” structure. The tris structure is preferred because it is believed to be particularly stable.
In one embodiment, m + n is equal to the total number of bidentate ligands that can bind to the metal in question, eg, 3 for Ir. In another embodiment, m + n can be less than the maximum number of bidentate ligands that can bind to the metal, in which case other ligands (auxiliary, photoactive, or others) are also It can also be bonded to metals. When different photoactive ligands bonded to the metal are present, each photoactive ligand preferably has a structure represented by the formula (1).

  In the present invention, the compound represented by the formula (21) is preferably represented by the following formula (22).

  In the present invention, the compound represented by the formula (20) is preferably represented by the following formula (23).

  In the present invention, the compound represented by the formula (23) is preferably represented by the following formula (24).

In the present invention, in the formula (24), m is preferably 3, and n is preferably 0.
In the present invention, in the formula (24), m may be 2 and n may be 1.

  In the present invention, the compound represented by the formula (24) is preferably represented by the following formula (25).

With respect to the manner in which the phosphorescent dopants of the present invention function, it is not limited to any theory, but it is believed that the combination of R ₃ ′ and R ₅ disclosed in formula (1) results in a luminescent material with enhanced stability. It is done. In particular, it is believed that the particular substituent shown in formula (9) results in a particularly stable molecule, ie, R ₅ is phenyl and R ₃ 'is not both substituted with methyl. It is further believed that enhanced stability still exists when phenyl and / or methyl at the R ₅ and R ₃ 'positions, respectively, are substituted. In addition, substitution at the R ₃ 'position has been found to extend the lifetime of the device. Substitution at the R ₅ position has also been found to extend the lifetime of the device, as disclosed in Brown et al. US patent application Ser. No. 10 / 289,915, which is incorporated by reference in its entirety. In the present invention, R 3 _{'substitution} at the position of and R _5, R _3' indicate that as compared to the replacement of only the position or R _5, further improving the life of the device.

In the present invention, the phosphorescent dopant preferably has a wavelength of maximum emission luminance of 520 nm or more and 700 nm or less.
The wavelength of the maximum emission luminance is more preferably 580 nm or more and 680 nm or less, and further preferably 600 nm or more and 660 nm or less.
By doping a phosphorescent dopant having such an emission wavelength into the host material of the present invention to form a light emitting layer, a highly efficient light emitting element can be obtained.

  In the present invention, the organic thin film layer preferably has an electron injection layer between the cathode and the phosphorescent light emitting layer, and the electron injection layer preferably contains a nitrogen-containing heterocyclic derivative.

  The electron injection layer or the electron transport layer is a layer that assists injection of electrons into the light emitting layer and has a high electron mobility. The electron injection layer is provided to adjust the energy level, for example, to alleviate a sudden change in the energy level. As a material used for the electron injection layer or the electron transport layer, 8-hydroxyquinoline or a metal complex of a derivative thereof, an oxadiazole derivative, or a nitrogen-containing heterocyclic derivative is preferable. As a specific example of the metal complex of 8-hydroxyquinoline or a derivative thereof, a metal chelate oxinoid compound containing a chelate of oxine (generally 8-quinolinol or 8-hydroxyquinoline), for example, tris (8-quinolinol) aluminum is used. Can do. And as an oxadiazole derivative, the following can be mentioned.

(In the formula, Ar ¹⁷ , Ar ¹⁸ , Ar ¹⁹ , Ar ²¹ , Ar ²² and Ar ²⁵ each represent an aryl group having or not having a substituent, Ar ¹⁷ and Ar ¹⁸ , Ar ¹⁹ and Ar ²¹ and Ar ^22. And Ar ²⁵ may be the same or different, Ar ²⁰ , Ar ²³ and Ar ²⁴ each represent an arylene group with or without a substituent, and Ar ²³ and Ar ²⁴ may be the same or different. May be.)
Examples of the arylene group include a phenylene group, a naphthylene group, a biphenylene group, an anthranylene group, a peryleneylene group, and a pyrenylene group. And as a substituent to these, a C1-C10 alkyl group, a C1-C10 alkoxy group, a cyano group, etc. are mentioned. As this electron transfer compound, those having good thin film forming properties are preferably used. Specific examples of these electron transfer compounds include the following.

  Examples of the nitrogen-containing heterocyclic derivative include nitrogen-containing heterocyclic derivatives composed of organic compounds having the following general formula and not a metal complex. For example, a 5-membered ring or 6-membered ring containing the skeleton shown in (A) and a structure shown in Formula (B) can be given.

(In the formula (B), X represents a carbon atom or a nitrogen atom. Z ₁ and Z ₂ each independently represent an atomic group capable of forming a nitrogen-containing heterocycle.)

  Preferably, the organic compound has a skeleton having a nitrogen-containing aromatic polycyclic group consisting of a 5-membered ring or a 6-membered ring, and in the case of a plurality of nitrogen atoms, having a bond position that is not adjacent. Further, in the case of such a nitrogen-containing aromatic polycyclic group having a plurality of nitrogen atoms, the nitrogen-containing aromatic polycyclic organic compound having a skeleton obtained by combining the above (A) and (B) or (A) and (C) .

  The nitrogen-containing group of the nitrogen-containing organic compound is selected from, for example, nitrogen-containing heterocyclic groups represented by the following general formula.

  (In the formulas (2) to (24), R is an aryl group having 6 to 40 carbon atoms, a heteroaryl group having 3 to 40 carbon atoms, an alkyl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms. And n is an integer of 0 to 5, and when n is an integer of 2 or more, a plurality of R may be the same or different from each other.

Furthermore, preferred specific compounds include nitrogen-containing heterocyclic derivatives represented by the following formula.

(In the formula, HAr is a nitrogen-containing heterocyclic ring having 3 to 40 carbon atoms which may have a substituent, and L ¹ is a single bond and having 6 to 40 carbon atoms which may have a substituent. An arylene group or a heteroarylene group having 3 to 40 carbon atoms which may have a substituent, and Ar ¹ is a divalent aromatic hydrocarbon group having 6 to 40 carbon atoms which may have a substituent. Ar ² is an aryl group having 6 to 40 carbon atoms which may have a substituent or a heteroaryl group having 3 to 40 carbon atoms which may have a substituent.

  HAr is selected from the following group, for example.

L ¹ is selected from the following group, for example.

Ar ² is selected from the following group, for example.

Ar ¹ is selected from, for example, the following arylanthranyl groups.

(In the formula, R ^{1 to} R ¹⁴ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aryloxy group having 6 to 40 carbon atoms, An aryl group having 6 to 40 carbon atoms or a heteroaryl group having 3 to 40 carbon atoms which may have a substituent, and Ar ³ is an aryl having 6 to 40 carbon atoms which may have a substituent. Group or a heteroaryl group having 3 to 40 carbon atoms.)
In Ar ¹ represented by the above formula, each of R ^{1 to} R ⁸ is a nitrogen-containing heterocyclic derivative that is a hydrogen atom.

  In addition, the following compounds (see JP-A-9-3448) are also preferably used.

Wherein R _{1 to} R ₄ are each independently a hydrogen atom, a substituted or unsubstituted aliphatic group, a substituted or unsubstituted aliphatic cyclic group, a substituted or unsubstituted carbocyclic aromatic ring group Represents a substituted or unsubstituted heterocyclic group, and X ₁ and X ₂ each independently represents an oxygen atom, a sulfur atom or a dicyanomethylene group.)

  In addition, the following compounds (see JP 2000-173774 A) are also preferably used.

In the formula, R ¹ , R ² , R ^3, and R ⁴ are the same or different groups, and are aryl groups represented by the following formula.

(In the formula, R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ are the same or different groups, and a hydrogen atom or at least one of them is a saturated or unsaturated alkoxyl group, an alkyl group, an amino group. Or an alkylamino group.)

  Further, it may be a polymer compound containing the nitrogen-containing heterocyclic group or nitrogen-containing heterocyclic derivative.

Although the film thickness of an electron injection layer or an electron carrying layer is not specifically limited, Preferably, it is 1-100 nm.

In this invention, it is preferable that the reducing dopant is added to the interface area | region of a cathode and an organic thin film layer.
According to such a configuration, it is possible to improve the light emission luminance and extend the life of the organic EL element.
Here, the reducing dopant is defined as a substance capable of reducing the electron transporting compound. Accordingly, various materials can be used as long as they have a certain reducibility, such as alkali metals, alkaline earth metals, rare earth metals, alkali metal oxides, alkali metal halides, alkaline earth metals. At least selected from the group consisting of oxides, alkaline earth metal halides, rare earth metal oxides or rare earth metal halides, alkali metal organic complexes, alkaline earth metal organic complexes, rare earth metal organic complexes One substance can be preferably used.

More specifically, preferable reducing dopants include Li (work function: 2.9 eV), Na (work function: 2.36 eV), K (work function: 2.28 eV), Rb (work function: 2). .16 eV) and Cs (work function: 1.95 eV), at least one alkali metal selected from the group consisting of Ca (work function: 2.9 eV), Sr (work function: 2.0 to 2.5 eV) And at least one alkaline earth metal selected from the group consisting of Ba (work function: 2.52 eV). A work function of 2.9 eV or less is particularly preferable.
Among these, a more preferable reducing dopant is at least one alkali metal selected from the group consisting of K, Rb and Cs, more preferably Rb or Cs, and most preferably Cs. These alkali metals have particularly high reducing ability, and the addition of a relatively small amount to the electron injection region can improve the light emission luminance and extend the life of the organic EL element. Further, as a reducing dopant having a work function of 2.9 eV or less, a combination of two or more alkali metals is also preferable. Particularly, a combination containing Cs, such as Cs and Na, Cs and K, Cs and Rb, or Cs. And a combination of Na and K. By including Cs in combination, the reducing ability can be efficiently exhibited, and by adding to the electron injection region, the emission luminance and the life of the organic EL element can be improved.

  Hereinafter, preferred embodiments of the present invention will be described.

[Organic EL device]
In FIG. 1, schematic structure of the organic EL element of this embodiment is shown.
The organic EL element 1 includes a transparent substrate 2, an anode 3, a cathode 4, and an organic thin film layer 10 disposed between the anode 3 and the cathode 4.
The organic thin film layer 10 has a phosphorescent light-emitting layer 5 containing a host and a phosphorescent dopant, and a hole injection / transport layer 6 or the like between the phosphorescent light-emitting layer 5 and the anode 3 and between the phosphorescent light-emitting layer 5 and the cathode 4. May be provided with an electron injection / transport layer 7 or the like.
Further, an electron blocking layer may be provided on the phosphorescent light emitting layer 5 on the anode 3 side, and a hole blocking layer may be provided on the phosphorescent light emitting layer 5 on the cathode 4 side.
Thereby, electrons and holes can be confined in the phosphorescent light-emitting layer 5, and the exciton generation probability in the phosphorescent light-emitting layer 5 can be increased.

(Example)
EXAMPLES Next, although an Example and a comparative example are given and this invention is demonstrated in more detail, this invention is not restrict | limited at all to the description content of these Examples.
In Table 3 below, physical property values of each material are described. The physical property values were measured as follows.
The triplet energy gap Eg (T) was defined based on the phosphorescence emission spectrum.
That is, each material is dissolved at 10 μmol / L in an EPA solvent (diethyl ether: isopentane: ethanol = 5: 5: 2 by volume ratio) to obtain a sample for phosphorescence measurement.
Then, the phosphorescence measurement sample is put in a quartz cell, cooled to 77K, irradiated with excitation light, and the wavelength of the emitted phosphorescence is measured.
A triplet energy gap Eg (T) is obtained by drawing a tangent line to the short-wavelength rise of the obtained phosphorescence spectrum and converting the wavelength value at the intersection of this tangent line and the base line (absorption zero) into energy. To do.
A commercially available measuring device F-4500 (manufactured by Hitachi) was used for the measurement.

The affinity level Af (electron affinity) refers to the energy released or absorbed when one electron is given to the molecule of the material, and is defined as positive in the case of emission and negative in the case of absorption.
The affinity level Af is defined by the ionization potential Ip and the optical energy gap Eg (S) as follows.
Af = Ip-Eg (S)
Here, the ionization potential Ip means the energy required to remove and ionize electrons from the compound of each material, and is, for example, a value measured with an ultraviolet photoelectron spectrometer (AC-3, Riken instrument). is there.
The optical energy gap Eg (S) refers to the difference between the conduction level and the valence level. For example, the wavelength value at the intersection of the long-wavelength side tangent of the absorption spectrum of the toluene dilute solution of each material and the baseline (zero absorption). Was calculated in terms of energy.

[Example 1]
A glass substrate with an ITO transparent electrode having a thickness of 25 mm × 75 mm × 1.1 mm (manufactured by Geomatic) was ultrasonically cleaned in isopropyl alcohol for 5 minutes, followed by UV ozone cleaning for 30 minutes.
The glass substrate with the transparent electrode line after washing is attached to the substrate holder of the vacuum deposition apparatus, and first, 4,4 ′ having a thickness of 55 nm is formed on the surface on which the transparent electrode line is formed so as to cover the transparent electrode. A -bis [N- (1-naphthyl) -N-phenylamino] biphenyl film (hereinafter abbreviated as “NPD film”) was formed by resistance heating vapor deposition. This NPD film functions as a hole injection / transport layer.
Next, a 4,4 ′, 4 ″ -Tris (carbazol-9-yl) triphenylamine film (hereinafter abbreviated as “TCTA film”) having a thickness of 20 nm was formed on the NPD film by resistance heating evaporation. .
This TCTA film functions as a charge blocking layer.
Furthermore, a compound represented by the following formula (H1) was formed on the TCTA film by resistance heating vapor deposition to a thickness of 30 nm. At the same time, a compound represented by the following formula (D1) was deposited as a phosphorescent dopant so as to be 5% by mass with respect to the compound (H1). This film functions as a phosphorescent light emitting layer.
Next, a compound represented by the following formula (HB) was formed on the phosphorescent layer so as to have a thickness of 10 nm by resistance heating vapor deposition. This compound (HB) film functions as a hole blocking layer.
A 30-nm thick tris (8-quinolinol) aluminum (Alq) complex was formed on this film. This functions as an electron injection layer.
Thereafter, Li (Li source: manufactured by SAES Getter Co.), which is a reducing dopant, and Alq were vapor-deposited, and an Alq: Li film (film thickness: 0.5 nm) was formed as an electron injection layer.
Metal Al was vapor-deposited on the Alq: Li film to form a metal cathode (film thickness: 150 nm), thereby forming an organic EL light emitting device.

[ Reference Example 2, Examples 3 to 7]
An organic EL device was produced in the same manner as in Example 1 except that the compounds represented by the following formulas (H2) to (H7) were used instead of the compound (H1).

[Comparative Examples 1-3]
An organic EL device was produced in the same manner as in Example 1 except that CBP, a compound represented by the following formula (H8) or formula (H9) was used instead of the compound (H1).

[Example 8 , Reference Example 9, Examples 10-14]
An organic EL device was produced in the same manner as in Example 1 , Reference Example 2, and Examples 3 to 7, respectively, except that the compound represented by the following formula (D2) was used as the phosphorescent dopant instead of the compound (D1). did.
[Comparative Examples 4 to 6]
Organic EL devices were produced in the same manner as in Comparative Examples 1 to 3, respectively, except that the compound represented by the following formula (D2) was used as the phosphorescent dopant instead of the compound (D1).

[Evaluation of organic EL elements]
A direct current was passed through the organic EL element produced as described above to emit light, and emission chromaticity, luminance (L), and voltage were measured.
Based on this, the external quantum efficiency (EQE) was determined. Further, a half-life of each organic EL element was measured by performing a DC continuous current test with an initial luminance of 1000 cd / m ² .
The results are shown in Tables 1 and 2 below, as well as the excited singlet energy gap (Eg (S)) and excited triplet energy gap (Eg (T)) of compounds (H1) to (H9) and CBP. Is shown in Table 3 below.

As is clear from Tables 1 and 2 , the organic EL elements of Example 1 , Examples 3 to 8, and Examples 10 to 14 configured using the host material of the present invention have a long lifetime. Further, it can be seen that the external quantum efficiency is high and a highly efficient light-emitting element can be configured.
In contrast, Comparative Examples 1 and 4 using CBP as a conventional host material have a short life.
In Comparative Examples 2 and 3 and Comparative Examples 5 and 6, since a compound having a narrow triplet energy gap is used as the phosphorescent dopant host, energy transfer does not occur from the host to the phosphorescent dopant, and the phosphorescent dopant emits light. Was not observed.

Note that the present invention is not limited to the above description, and modifications within a range not departing from the gist of the present invention are included in the present invention.
For example, the following changes are also preferable modifications of the present invention.
In the present invention, the light emitting layer preferably contains a charge injection auxiliary material.
When a phosphorescent light emitting layer is formed using a host material having a wide energy gap as described above, the difference between the ionization potential (Ip) of the host material and Ip of the hole injection / transport layer and the like becomes large, and the phosphorescent light emitting layer is formed. Hole injection becomes difficult, and the drive voltage for obtaining sufficient luminance may increase.
In such a case, by adding a hole injection / transport charge injection auxiliary agent to the phosphorescent light-emitting layer, hole injection into the phosphorescent light-emitting layer can be facilitated and the driving voltage can be reduced.
As the charge injection auxiliary agent, for example, a general hole injection / transport material or the like can be used.
Specific examples include triazole derivatives (see US Pat. No. 3,112,197), oxadiazole derivatives (see US Pat. No. 3,189,447, etc.), imidazole derivatives (Japanese Patent Publication No. 37-16096). Polyarylalkane derivatives (US Pat. Nos. 3,615,402, 3,820,989, 3,542,544, JP-B-45-555). 51-10983, JP-A-51-93224, 55-17105, 56-4148, 55-108667, 55-156953, 56-36656 See the publication)
Pyrazoline derivatives and pyrazolone derivatives (US Pat. Nos. 3,180,729, 4,278,746, JP-A-55-88064, JP-A-55-88065, JP-A-49-105537) No. 55-51086, No. 56-80051, No. 56-88141, No. 57-45545, No. 54-112737, No. 55-74546, etc.), phenylenediamine derivatives (See U.S. Pat. No. 3,615,404, JP-B-51-10105, JP-B-46-3712, JP-B-47-25336, JP-B-54-11925, etc.), arylamine derivatives (US Patent No. 3,567,450, No. 3,240,597, No. 3,658,520, No. No. 232,103, No. 4,175,961, No. 4,012,376, JP-B-49-35702, JP-A-39-27577, JP-A-55- 144250, 56-119132, 56-22437, West German Patent 1,110,518, etc.), amino-substituted chalcone derivatives (US Pat. No. 3,526,501, etc.) Oxazole derivatives (disclosed in US Pat. No. 3,257,203, etc.), styryl anthracene derivatives (see JP 56-46234 A, etc.), fluorenone derivatives (JP 51-110837 A). Hydrazone derivatives (US Pat. No. 3,717,462, JP-A-54-59143, 55-52063, No. 5-52064, No. 55-46760, No. 57-11350, No. 57-148799, JP-A-2-311591, etc.), Stilbene derivatives (JP-A No. 61-210363), 61-228451, 61-14642, 61-72255, 62-47646, 62-36684, 62-10652, 62-30255, 60-93455, 60-94462, 60-174749, 60-175052, etc.), silazane derivatives (US Pat. No. 4,950,950), polysilane ( JP-A-2-204996), aniline copolymer (JP-A-2-282263), conductive polymer oligomer -(Particularly thiophene oligomer).

Examples of the hole-injecting material include the above materials, but porphyrin compounds (disclosed in JP-A-63-295695), aromatic tertiary amine compounds and styrylamine compounds (US patents) No. 4,127,412, JP-A-53-27033, 54-58445, 55-79450, 55-144250, 56-119132, 61- 295558, 61-98353, 63-295695, etc.), particularly aromatic tertiary amine compounds are preferred.
In addition, for example, 4,4′-bis (N- (1-naphthyl) -N-phenylamino having two condensed aromatic rings described in US Pat. No. 5,061,569 in the molecule. ) Biphenyl (hereinafter abbreviated as NPD), and 4,4 ′, 4 ″ -tris (N- ( 3-methylphenyl) -N-phenylamino) triphenylamine (hereinafter abbreviated as MTDATA) and the like.
Further, hexaazatriphenylene derivatives described in Japanese Patent Publication Nos. 3614405, 3571977 or US Pat. No. 4,780,536 can also be suitably used as the hole injecting material.
In addition, inorganic compounds such as p-type Si and p-type SiC can also be used as the hole injection material.

  The present invention can be used as an organic EL device having a phosphorescent light emitting layer.

It is a figure which shows schematic structure of the organic EL element which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Organic EL element 2 Substrate 3 Anode 4 Cathode 5 Phosphorescent light emitting layer 6 Hole injection / transport layer 7 Electron injection / transport layer 10 Organic thin film layer

Claims (41)

An organic EL device comprising an anode, a cathode, and an organic thin film layer provided between the anode and the cathode,
The organic thin film layer has a phosphorescent light emitting layer containing a host and a phosphorescent dopant,
The host is
A host material having a substituted or unsubstituted polycyclic fused aromatic skeleton having 14 to 30 nuclear atoms and a lowest excited triplet energy gap of 2.1 eV or more and 2.7 eV or less;
The phosphorescent dopant may have a ligand represented by the following formula (1),
The polycyclic fused aromatic skeleton is represented by any of the following formula (3), formula (4), formula (51), formula (52), formula (53), or formula (54). An organic EL device characterized by that.

(In the formula (1),
R ₃ ′ is a substituent selected from the group consisting of alkyl, heteroalkyl, aryl, heteroaryl, and aralkyl, and R ₃ ′ may be optionally substituted with one or more substituents Z;
R ₅ is a substituent selected from the group consisting of aryl and heteroaryl, said aryl or heteroaryl being unsubstituted or optionally substituted with one or more non-aromatic groups;
Ring A is an aromatic heterocyclic or fused aromatic heterocyclic ring having at least one nitrogen atom coordinated to the metal, and ring A is optionally selected by one or more non-aromatic groups. Can be replaced,
R ₃ is H, alkyl, alkenyl, alkynyl, alkylaryl, CN, CF ₃ , CnF _{2n + 1} , trifluorovinyl, CO ₂ R, C (O) R, NR ₂ , NO ₂ , OR, halo, aryl, hetero A substituent selected from the group consisting of aryl, substituted aryl, substituted heteroaryl or heterocyclic group;
R ₄ is H, alkyl, alkenyl, alkynyl, alkylaryl, CN, CF ₃ , CnF _{2n + 1} , trifluorovinyl, CO ₂ R, C (O) R, NR ₂ , NO ₂ , OR, halo, aryl, hetero A substituent selected from the group consisting of aryl, substituted aryl, substituted heteroaryl or heterocyclic group;
In addition or alternatively, R ₃ and R ₄ are taken together to independently form a fused 4-7 membered cyclic group, which can be cycloalkyl, cycloheteroalkyl, aryl, or heteroaryl And the cyclic group may be optionally substituted with one or more substituents Z,
R ₆ is H, alkyl, alkenyl, alkynyl, alkylaryl, CN, CF ₃ , CnF _{2n + 1} , trifluorovinyl, CO ₂ R, C (O) R, NR ₂ , NO ₂ , OR, halo, aryl, hetero A substituent selected from the group consisting of aryl, substituted aryl, substituted heteroaryl or heterocyclic group;
Alternatively, _{R 3} 'and _{R 6, -CR 2 -CR 2 -, -} CR = CR -, - CR 2 -, - O -, - NR -, - O-CR 2 -, - NR-CR 2 - And may be bridged by a group selected from —N═CR—, wherein each R is independently H, alkyl, alkenyl, alkynyl, heteroalkyl, aryl, heteroaryl, or aralkyl, wherein R is Optionally substituted by one or more substituents Z,
Each Z is independently halogen, R ′, OR ′, N (R ′) ₂ , SR ′, C (O) R ′, C (O) OR ′, C (O) N (R ′) ₂ , CN, NO ₂ , SO ₂ , SOR ′, SO ₂ R ′,
Or SO ₃ R ′,
Each R ′ is independently H, alkyl, perhaloalkyl, alkenyl, alkynyl, heteroalkyl, aryl, or heteroaryl. )
(In the formulas (3) to (4), Ar ^{2 to} Ar ⁴ represent a substituted or unsubstituted condensed ring structure having 4 to 10 nuclear carbon atoms.) The organic EL device according to claim 1,
The organic EL device, wherein the polycyclic fused aromatic skeleton is contained in the chemical structural formula as a divalent or higher valent group. The organic EL device according to claim 1,
The polycyclic fused aromatic skeleton has a substituent,
The organic EL element, wherein the substituent is a substituted or unsubstituted aryl group or heteroaryl group (excluding those having a carbazole skeleton). The organic EL device according to claim 2,
The polycyclic fused aromatic skeleton is substituted or unsubstituted click Risenjiiru, organic EL elements, characterized in that it is selected from the group of fluoranthene diisopropyl Le. The organic EL device according to claim 4,
The organic EL device, wherein the polycyclic fused aromatic skeleton is substituted with a group having phenanthrene, chrysene, fluoranthene, or triphenylene. In the organic EL element according to any one of claims 1 to 5 ,
The ligand represented by said Formula (1) is represented by following formula (5). The organic EL element characterized by the above-mentioned.

(In Formula (5),
R ₄ ′, R ₅ ′, and R ₆ ′ are each independently H, alkyl, alkenyl, alkynyl, heteroalkyl, alkenyl, alkynyl, heteroalkyl, aryl, heteroaryl, aralkyl; R ₄ ′, R ₅ ′, and R ₆ ′ may be optionally substituted with one or more substituents Z;
In addition or alternatively, any one or more of R ₄ ′ and R ₅ ′, or R ₅ ′ and R ₆ ′, or R ₃ and R ₄ are taken together to form an independently fused 4-7 membered cyclic group Wherein the cyclic group is cycloalkyl, cycloheteroalkyl, aryl, or heteroaryl; the cyclic group may be optionally substituted with one or more substituents Z;
Additionally or alternatively, _{R 3} 'and _{R 6} have the _{formula: -CR 2 -CR 2 -, -} CR = CR -, - CR 2 -, - O -, - NR -, - O-CR 2 -, Linked by a group having —NR—CR ₂ —, —N═CR—, R is selected from the group consisting of H, alkyl, aryl, and aralkyl. ) The organic EL element according to claim 6 ,
The ligand represented by said Formula (5) is represented by following formula (6). The organic EL element characterized by the above-mentioned.
The organic EL element according to claim 6 ,
The ligand represented by said Formula (5) is represented by following formula (7). The organic EL element characterized by the above-mentioned.
The organic EL element according to claim 6 ,
The ligand represented by said Formula (5) is represented by following formula (8). The organic EL element characterized by the above-mentioned.
The organic EL element according to claim 6 ,
In the formula (5), R ₅ is substituted or unsubstituted phenyl, naphthyl, or pyridyl. The organic EL device according to claim 10 ,
R ₅ is an organic EL element which is a phenyl. In the organic EL device according to claim 10 or 11 ,
In said formula (5), R < ₃ '> is a methyl group. The organic EL element characterized by the above-mentioned. The organic EL element according to claim 6 ,
The ligand represented by said Formula (5) is represented by following formula (9). The organic EL element characterized by the above-mentioned.

Wherein R ₅ ′ and R ₆ ′ are H, and in addition or alternatively, together form a fused 4-7 membered cyclic group, said cyclic group being cycloalkyl , Cycloheteroalkyl, aryl, or heteroaryl.) The organic EL device according to claim 13 ,
The ligand represented by the formula (9) is represented by the following formula (10).
The organic EL device according to claim 14 , wherein
The ligand represented by said Formula (10) is represented by following formula (11). The organic EL element characterized by the above-mentioned.
The organic EL device according to claim 13 ,
The ligand represented by the formula (9) is represented by the following formula (12).
The organic EL device according to claim 16 , wherein
The ligand represented by the formula (12) is represented by the following formula (13).
In the organic EL element according to any one of claims 1 to 5 ,
The phosphorescent dopant is represented by the following formula (14). An organic EL device, wherein:

(In the formula (14), M is a metal having an atomic weight of more than 40,
R ₃ ′ is a substituent selected from the group consisting of alkyl, heteroalkyl, aryl, heteroaryl, and aralkyl, and R ₃ ′ may be optionally substituted with one or more substituents Z;
R ₅ is a substituent selected from the group consisting of aryl and heteroaryl, said aryl or heteroaryl being unsubstituted or optionally substituted with one or more non-aromatic groups;
Ring A is an aromatic heterocyclic ring or a condensed aromatic heterocyclic ring having at least one nitrogen atom coordinated to the metal M, and ring A is optionally selected by one or more non-aromatic groups. Can be replaced by selection,
R ₃ is H, alkyl, alkenyl, alkynyl, alkylaryl, CN, CF ₃ , CnF _{2n + 1} , trifluorovinyl, CO ₂ R, C (O) R, NR ₂ , NO ₂ , OR, halo, aryl, hetero A substituent selected from the group consisting of aryl, substituted aryl, substituted heteroaryl or heterocyclic group;
R ₄ is H, alkyl, alkenyl, alkynyl, alkylaryl, CN, CF ₃ , CnF _{2n + 1} , trifluorovinyl, CO ₂ R, C (O) R, NR ₂ , NO ₂ , OR, halo, aryl, hetero A substituent selected from the group consisting of aryl, substituted aryl, substituted heteroaryl or heterocyclic group;
In addition or alternatively, R ₃ and R ₄ are taken together to independently form a fused 4-7 membered cyclic group, which can be cycloalkyl, cycloheteroalkyl, aryl, or heteroaryl And the cyclic group may be optionally substituted with one or more substituents Z,
R ₆ is H, alkyl, alkenyl, alkynyl, alkylaryl, CN, CF ₃ , CnF _{2n + 1} , trifluorovinyl, CO ₂ R, C (O) R, NR ₂ , NO ₂ , OR, halo, aryl, hetero A substituent selected from the group consisting of aryl, substituted aryl, substituted heteroaryl or heterocyclic group;
Alternatively, _{R 3} 'and _{R 6, -CR 2 -CR 2 -, -} CR = CR -, - CR 2 -, - O -, - NR -, - O-CR 2 -, - NR-CR 2 - And may be cross-linked by a group selected from -N = CR-
Each R is independently H, alkyl, alkenyl, alkynyl, heteroalkyl, aryl, heteroaryl, or aralkyl, wherein R is optionally substituted by one or more substituents Z;
Each Z is independently halogen, R ′, OR ′, N (R ′) ₂ , SR ′, C (O) R ′, C (O) OR ′, C (O) N (R ′) ₂ , CN, NO ₂ , SO ₂ , SOR ′, SO ₂ R ′,
Or SO ₃ R ′,
Each R ′ is independently H, alkyl, perhaloalkyl, alkenyl, alkynyl, heteroalkyl, aryl, or heteroaryl;
(XY) is an auxiliary ligand, m is a value from 1 to the maximum number of ligands that can bind to the metal,
m + n is the maximum number of ligands that can bind to the metal. ) The organic EL device according to claim 18 ,
The compound represented by the formula (14) is represented by the following formula (15).

(In formula (15),
R ₄ ′, R ₅ ′, and R ₆ ′ are each independently H, alkyl, alkenyl, alkynyl, heteroalkyl, alkenyl, alkynyl, heteroalkyl, aryl, heteroaryl, aralkyl; R ₄ ′, R ₅ ′, and R ₆ ′ may be optionally substituted with one or more substituents Z;
In addition or alternatively, any one or more of R ₄ ′ and R ₅ ′, or R ₅ ′ and R ₆ ′, or R ₃ and R ₄ are taken together to form an independently fused 4-7 membered cyclic group Wherein the cyclic group is cycloalkyl, cycloheteroalkyl, aryl, or heteroaryl; the cyclic group may be optionally substituted with one or more substituents Z;
Additionally or alternatively, _{R 3} 'and _{R 6} have the _{formula: -CR 2 -CR 2 -, -} CR = CR -, - CR 2 -, - O -, - NR -, - O-CR 2 -, Linked by a group having —NR—CR ₂ —, —N═CR—, R is selected from the group consisting of H, alkyl, aryl, and aralkyl. ) The organic EL device according to claim 19 ,
The compound represented by the formula (15) is represented by the following formula (16). An organic EL device, wherein:
The organic EL device according to claim 19 , wherein the compound represented by the formula (15) is represented by the following formula (17).
The organic EL device according to claim 19 ,
The compound represented by said Formula (15) is represented by following formula (18). The organic EL element characterized by the above-mentioned.
The organic EL device according to claim 19 ,
In the formula (15), R ₅ is substituted or unsubstituted phenyl, naphthyl, or pyridyl. An organic EL element, wherein The organic EL element according to claim 23 ,
R ₅ is an organic EL element which is a phenyl. The organic EL device according to claim 23 or claim 24 ,
In said formula (15), R < ₃ '> is a methyl group. The organic EL element characterized by the above-mentioned. The organic EL device according to claim 19 ,
The compound represented by said Formula (15) is represented by following formula (19). The organic EL element characterized by the above-mentioned.

Wherein R ₅ ′ and R ₆ ′ are H, and in addition or alternatively, together form a fused 4-7 membered cyclic group, said cyclic group being cycloalkyl , Cycloheteroalkyl, aryl, or heteroaryl.) The organic EL device according to claim 26 ,
In the formula (19), M is selected from the group consisting of Ir, Pt, Pd, Rh, Re, Ru, Os, Tl, Pb, Bi, In, Sn, Sb, Te, Au, and Ag. A characteristic organic EL element. The organic EL device according to claim 27 ,
M is Ir. The organic EL element characterized by the above-mentioned. The organic EL device according to claim 28 ,
The compound represented by said Formula (19) is represented by following formula (20). The organic EL element characterized by the above-mentioned.
The organic EL device according to claim 29 ,
The compound represented by the formula (20) is represented by the following formula (21).
The organic EL device according to claim 30 , wherein
In said Formula (21), m is 3, n is 0. The organic EL element characterized by the above-mentioned. The organic EL device according to claim 30 , wherein
In the formula (21), m is 2, and n is 1. An organic EL element, wherein: The organic EL device according to claim 32 ,
The compound represented by the formula (21) is represented by the following formula (22).
The organic EL device according to claim 28 ,
The compound represented by the formula (20) is represented by the following formula (23).
The organic EL device according to claim 34 ,
The compound represented by the formula (23) is represented by the following formula (24).
The organic EL device according to claim 35 ,
In said Formula (24), m is 3, n is 0. The organic EL element characterized by the above-mentioned. The organic EL device according to claim 35 ,
In said Formula (24), m is 2, n is 1, The organic EL element characterized by the above-mentioned. The organic EL device according to claim 37 ,
The compound represented by the formula (24) is represented by the following formula (25).
In the organic EL device according to any one of claims 1 to 38 ,
The phosphorescent dopant has a wavelength of maximum emission luminance of 520 nm or more and 700 nm or less. The organic EL device according to any one of claims 1 to 39 ,
The organic thin film layer has an electron injection layer between the cathode and the phosphorescent light emitting layer,
The electron injection layer includes a nitrogen-containing heterocyclic derivative. An organic EL device, wherein: The organic EL device according to any one of claims 1 to 40 , wherein
An organic EL element, wherein a reducing dopant is added to an interface region between the cathode and the organic thin film layer.