JP2009147324A - Organic el element and solution containing organic el material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL element emitting phosphorescent light of long lifetime in a range of wavelength useful for practical use. <P>SOLUTION: An organic EL element, comprising: a positive electrode 3; a negative electrode 8; and an organic thin film layer provided between the positive electrode 3 and the negative electrode 8, wherein the organic thin film layer includes a light emitting layer 5 containing a first polycyclic condensed aromatic compound having substituted or not substituted polycyclic condensed aromatic back bone and a first phosphorescent material providing phosphorescent emission, and an organic layer 6 containing a second polycyclic condensed aromatic compound having substituted or not substituted polycyclic condensed aromatic back bone on the negative electrode 8 side of the light emitting layer 5. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an organic EL element and a solution containing an organic EL material for forming the organic EL element.

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.

In addition, since exciton may be dispersed outside the light emitting layer before emitting light, an organic EL element in which a hole blocking layer is provided on the cathode side of the organic light emitting layer is considered. For example, materials such as BAlq and BCP are used for the hole blocking layer. In addition, there is an organic electroluminescent element using a compound containing phenanthrene for the hole blocking layer and further including a layer containing Ir (ppy) ₃ (see Patent Document 2).

US application 2002/182441 publication JP 2005-197262 A

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. .
Further, in Patent Document 2, although exciton deactivation can be eliminated, there is still room for improvement with respect to the lifetime of the organic EL element.
Accordingly, an object of the present invention is to provide a phosphorescent organic EL device that emits light at a practically effective emission wavelength and has a long lifetime.

  The organic EL device of the present invention includes an anode, a cathode, and an organic thin film layer provided between the anode and the cathode, and the organic thin film layer is a substituted or unsubstituted polycyclic condensed fragrance. A light-emitting layer having a first polycyclic fused aromatic compound having a group skeleton and a first phosphorescent material exhibiting phosphorescence emission; a substituted or unsubstituted polyvalent compound on the cathode side of the light-emitting layer; And an organic layer containing a second polycyclic fused aromatic compound having a cyclic fused aromatic skeleton.

In this invention, the organic layer functions as a hole blocking layer. Conventionally, unstable materials such as BAlq and BCP have been used as the hole blocking layer, but in the present invention, a stable polycyclic condensed aromatic compound is used. Therefore, the stability of the molecule can be increased and the device life can be extended.
On the other hand, anthracene, tetracene and the like used as a host material for fluorescence emission have a narrow triplet energy gap Eg (T) and cannot be used for phosphorescence emission. However, the present invention solves this by using a polycyclic fused aromatic compound having a wide triplet energy gap Eg (T) width as a host material.

  In the present invention, at least one of the first polycyclic fused aromatic compound and the second polycyclic fused aromatic compound has a lowest excited triplet energy gap of 2.1 eV or more. It is preferably 7 eV or less, and the number of nucleus atoms of the polycyclic fused aromatic skeleton is 10 to 30.

  Conventionally, CBP having a wide triplet energy gap has been studied as a host material corresponding to a phosphorescent material that can be widely applied to phosphorescent materials in a wide wavelength range from green to red. If it is too wide, the difference in energy gap is too large for the red phosphorescent light emitting material, so that intermolecular energy transfer is not performed efficiently and the lifetime is short. On the other hand, in the present invention, since the lowest excited triplet energy gap is 2.1 eV or more and 2.7 eV or less, it cannot be applied to a host of phosphorescent material having a wide gap as blue, but a phosphorescent material having 2.7 eV or less In particular, the energy gap is suitable for red phosphorescent materials, so that energy can be efficiently transferred from the host excitons to the phosphorescent materials, resulting in highly efficient and long-term stable phosphorescence emission. can get.

Here, 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. It is done.
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.

  Further, if the number of ring-forming atoms in the skeleton (not including the number of substituent atoms) is too small, the stability of the molecule will not be sufficiently high, so the number of ring-forming atoms (not including the number of substituent atoms) is 10 or more. On the other hand, if the number of polycyclic fused rings is too large, the HOMO-LUMO gap becomes narrow and the triplet energy gap becomes less than the useful emission wavelength, so the number of ring-forming atoms (the number of substituent atoms) (Not included) is 30 or less. A more preferable range of the number of ring-forming atoms (not including the number of substituent atoms) of the polycyclic fused aromatic skeleton is 20 or more and 30 or less.

  In the organic EL device of the present invention, the ionization potential of the second polycyclic fused aromatic compound is preferably larger than the ionization potential of the first polycyclic fused aromatic compound.

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 first phosphorescent material is a material that emits light by receiving energy transfer from the first polycyclic fused aromatic compound, or a material that emits light by directly generating excitons on the phosphorescent material.
In this invention, since the ionization potential of the second polycyclic fused aromatic compound is larger than the ionization potential of the first polycyclic fused aromatic compound, the energy gap at the time of hole injection into the light emitting layer and the organic layer Becomes stepwise, the load on the light emitting layer and the organic layer is reduced, and the device life can be extended.

  In the organic EL device of the present invention, the lowest excited triplet energy gap Eg (T2) of the second polycyclic fused aromatic compound is the lowest excited triplet energy of the first polycyclic fused aromatic compound. It is preferable to be larger than the gap Eg (T1).

  Here, the optical energy gap Eg (S) refers to the difference between the conduction level and the valence electron level. For example, the long-wavelength side tangent of the absorption spectrum of the diluted toluene solution of each material and the baseline (baseline obtained from the absorbance) ) Was calculated by converting the wavelength value of the intersection with) into energy.

Thus, by using different host materials (first polycyclic fused aromatic compound and second polycyclic fused aromatic compound) for the light emitting layer and the organic layer, the required performance required for the host material is separated. can do. For example, the second polycyclic fused aromatic compound bears the electron transporting function, so that the first polycyclic fused aromatic compound has a long life and high efficiency even though the electron transporting property is smaller. Can be selected from high materials.
In addition, the recombination region is confined inside the light emitting layer by combining the first polycyclic fused aromatic compound having a high hole transporting property and the second polycyclic fused aromatic compound having a high electron transporting property. Can do. Thereby, the leakage of electric charges to the hole transport layer and the electron transport layer can be reduced, and the lifetime can be prevented from being increased in efficiency and the deterioration of the transport material.

  In the organic EL device of the present invention, the organic layer preferably contains a second phosphorescent material that exhibits phosphorescence. The organic layer preferably contains the first phosphorescent material.

  In the present invention, the organic layer has both functions of a hole blocking layer and a light emitting layer. Therefore, it is possible to obtain an organic EL element having the above-described effects and having a function as a light emitting layer.

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 as —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, and 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-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, cyan Methyl 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, 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-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-pyridy Nyl 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- Isobenzofuranyl group, 2-quinolyl group, 3-quinolyl group, 4-quinolyl group, 5-quinolyl group, 6-quinolyl group, 7- Noryl 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, 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-phenanthro N-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-phenanthroline-9-yl group, 1,8-phenanthrolin-10-yl group, 1,9-phenanthrolin-2-yl group, 1,9-phenanthrolin-3-yl A group, a 1,9-phenanthrolin-4-yl group, a 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-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-phenanthroline -5-yl group, 2,9-phenanthrolin-6-yl group, 2,9-phenanthrolin-7-yl group, 2,9-phenanthrolin-8-yl group, 2,9-phen group Nansulolin-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, 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-phenothi Zinyl 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-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 Til-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-3-indolyl group, 4-t-butyl-3-indolyl group and the like can be mentioned.

  Examples of the substituted or unsubstituted alkyl group 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-trichloropropyl group, bromomethyl 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-cyano Sobutyl 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.

  Furthermore, examples of the substituted or unsubstituted alkenyl group include vinyl group, allyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group, 1,3-butanedienyl group, 1-methylvinyl group, styryl group. 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- Examples thereof include a phenyl-1-butenyl group and a 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- Lichloropropyl 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 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, A 3-trinitropropyl group and the like can be mentioned.

  Furthermore, 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- Tylphenyl 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-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-iso Nzofuranyl 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 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, , 7-phenanthroline-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-phen group Nanthrolin-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-phenanthro -6-yl group, 2,9-phenanthrolin-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-phenanthroline-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, 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-methylpyrrole -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-3-indolyl group, 4-t-butyl-3-indolyl group and the like can be mentioned.

  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 preferably has a substituent, and the substituent is preferably a substituted or unsubstituted aryl group or heteroaryl group. Moreover, it is preferable that the substituent of the said polycyclic fused aromatic skeleton part excludes what has a carbazole skeleton.
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 wider due to, for example, an increase in ionization potential, and hole injection from the stepwise anode to the first light-emitting layer and the second light-emitting layer It is difficult to obtain a multilayer structure for electron injection from the cathode, it is difficult to extend the lifetime of the device, and it can be applied as a host to phosphorescent materials having a shorter wavelength. The introduction is not preferable because it leads to a shortened life.
In this respect, it is preferable to remove the carbazole group from the substituent because the energy gap between the first light emitting layer and the second light emitting layer is narrowed but the lifetime can be extended.

In the present invention, the polycyclic fused aromatic skeleton is preferably selected from the group of substituted or unsubstituted phenanthrene diyl, chrysenediyl, fluoranthenediyl, and triphenylenediyl.
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 of the following formulas (1) to (4).

In the formulas (1) to (4), Ar ^{1 to} Ar ⁵ represent a substituted or unsubstituted ring-forming carbon number (not including the carbon number of the substituent) 4 to 10 condensed ring structure.
Examples of the compound represented by the formula (1) include substituted or unsubstituted phenanthrene and chrysene.
Examples of the compound represented by the formula (2) include substituted or unsubstituted acenaphthylene, acenaphthene, fluoranthene, and the like.
Examples of the compound represented by the formula (3) include substituted or unsubstituted benzofluoranthene.
Examples of the compound represented by the formula (4) include substituted or unsubstituted naphthalene alone or a derivative thereof.
As a naphthalene derivative, the thing of a following formula (4A) is mentioned, for example.

In formula (4A), R _{1 to} R ₈ are each independently a hydrogen atom, a ring-forming carbon number (not including the carbon number of the substituent) 5-30 substituent or an unsubstituted aryl group, carbon number A branched or straight chain alkyl group having 1 to 30 and a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms is a single or a combination of a plurality thereof.
Specific examples of naphthalene derivatives include the following.

  Moreover, in this invention, it is preferable that the said polycyclic fused aromatic skeleton part is a single-piece | unit or derivative | guide_body of phenanthrene represented by following formula (5).

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 those represented by the following formula (5A).

In formula (5A), R _{1 to} R ₁₀ are each independently a hydrogen atom, a ring-forming carbon number (not including the carbon number of the substituent) 5-30 substituent or an unsubstituted aryl group, carbon number A branched or straight chain alkyl group having 1 to 30 and a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms is a single or a combination of a plurality thereof.
Specific examples of the phenanthrene derivative represented by the formula (5) include the following.

  Furthermore, in the present invention, the polycyclic fused aromatic skeleton is preferably a simple substance or a derivative of chrysene represented by the following formula (6).

  Examples of such chrysene derivatives include those of the following formula (6A).

In formula (6A), R _{1 to} R ₁₂ are each independently a hydrogen atom, a ring-forming carbon number (not including the carbon number of the substituent) 5-30 substituent or an unsubstituted aryl group, carbon number A branched or straight chain alkyl group having 1 to 30 and a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms is a single or a combination of a plurality thereof.
Specific examples of the chrysene derivative represented by the formula (6) 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] phenanthrene) represented by the following formula (7).

  Examples of such a benzo [c] phenanthrene derivative include those represented by the following formula (7A).

In Formula (7A), R _{1 to} R ₉ are each independently a hydrogen atom, a ring-forming carbon number (not including the carbon number of the substituent) 5-30 substituent or an unsubstituted aryl group, carbon number A branched or straight chain alkyl group having 1 to 30 and a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms is a single or a combination of a plurality thereof.
Specific examples of the benzo [c] phenanthrene derivative represented by the formula (7) include the following.

  Furthermore, 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 (8).

  Examples of such a benzo [c] chrysene derivative include those represented by the following formula (8A).

In formula (8A), R _{1 to} R ₁₁ are each independently a hydrogen atom, a ring-forming carbon number (not including the carbon number of the substituent) 5-30 substituent or an unsubstituted aryl group, carbon number A branched or straight chain alkyl group having 1 to 30 and a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms is a single or a combination of a plurality thereof.
Specific examples of the benzo [c] chrysene derivative represented by the formula (8) include the following.
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 (dibenzo [c, g] phenanthrene) represented by the following formula (9).

  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 (10).

  Examples of such a fluoranthene derivative include those of the following formula (10A).

In formula (10A), X _{12 to} X ₂₁ represent a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group, a linear, branched or cyclic alkoxy group, or a substituted or unsubstituted aryl 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 _{12 to} X ₂₁ 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.), C1-C16 linear, branched or cyclic alkoxy group (for example, methoxy group, Xoxy 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- Dimethylbutyloxy 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-ethyl) Phenyl group, 4-n-propylphenyl group, 4-isopropylphenyl group, 4-n-butylphenyl Nyl 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-ethoxy Phenyl 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 -4-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-pyridyl group, 4-pyridyl group, etc.), 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 6 to 12 carbon atoms. And 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. A.

  Specific examples of the fluoranthene derivative represented by the formula (10) include the following.

  Examples of the substituted or unsubstituted benzofluoranthene include, for example, a simple substance or derivative of benzo [b] fluoranthene represented by the following formula (101), a simple substance of benzo [k] fluoranthene represented by the formula (102), or Derivatives.

In formula (101) and formula (102), 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, eth Si 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- Dimethylbutyloxy 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-ethyl) Phenyl group, 4-n-propylphenyl group, 4-isopropylphenyl group, 4-n-butylphenol 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-ethoxy Phenyl group, 4-n-propoxyphenyl group, 4-isopropoxyphenyl group, 4-n-butoxyphenyl group, 4-n-pentyloxyphenyl group, -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 4-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 -Pyridyl group, 4-pyridyl group, etc.), more preferably hydrogen atom, fluorine atom, chlorine atom, alkyl group having 1 to 10 carbon atoms, alkoxy group having 1 to 10 carbon atoms, or 6 to 12 carbon atoms. An aryl group, 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. That.

  Examples of the benzo [b] fluoranthene derivative represented by the formula (101) include the following.

  Examples of the benzo [k] fluoranthene derivative represented by the formula (102) include the following.

  Furthermore, in the present invention, the polycyclic fused aromatic skeleton is preferably a simple substance or a derivative of triphenylene represented by the following formula (11).

  Examples of such a triphenylene derivative include those represented by the following formula (11A).

In formula (11A), R _{1 to} R ₆ are each independently a hydrogen atom, a ring-forming carbon number (not including the carbon number of the substituent) 5-30 substituent or an unsubstituted aryl group, carbon number A branched or straight chain alkyl group having 1 to 30 and a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms is a single or a combination of a plurality thereof.
Specific examples of the triphenylene derivative represented by the formula (11) include the following.

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

In the present invention, at least one of the first phosphorescent light emitting material and the second phosphorescent light emitting material comprises a metal selected from Ir, Pt, Os, Au, Cu, Re, and Ru and a ligand. It is preferable to contain a metal complex.
Specific examples of the light-emitting material include, for example, PQIr (iridium (III) bis (2-phenylquinolyl-N, C2 ^′ ) acetylacetonate), Ir (ppy) ₃ (fac-tris (2-phenylpyridine) iridium) The following compounds are mentioned.

In the present invention, the first phosphorescent light emitting material and the second phosphorescent light emitting material preferably have a wavelength of maximum light emission luminance of 470 nm or more and 700 nm or less.
The wavelength of the maximum emission luminance is more preferably 480 nm or more and 680 nm or less, and further preferably 500 nm or more and 650 nm or less.
A first light emitting layer and a second light emitting layer obtained by doping a phosphorescent light emitting material having such an emission wavelength into a host material of a polycyclic condensed aromatic compound having a minimum excited triplet energy gap of 2.1 eV or more and 2.7 eV or less By configuring this, highly efficient light emission can be obtained.

The first light emitting layer and the second light emitting layer are preferably blue light emitting layers. The first light emitting layer and the second light emitting layer are preferably green light emitting layers. Further, the first light emitting layer and the second light emitting layer are preferably red light emitting layers.
That is, the first light emitting layer and the second light emitting layer of the present invention are formed of the same color light emitting layer.
When the first light-emitting layer and the second light-emitting layer are blue light-emitting layers, the light emission has a wavelength of 470 nm to 500 nm, and when the first light-emitting layer and the second light-emitting layer are green light-emitting layers, the wavelength is 500 nm to 580 nm. It emits light, and when the first light emitting layer and the second light emitting layer are red light emitting layers, it emits light having a wavelength of 580 nm to 700 nm.

In the present invention, the difference between the wavelength of the highest emission luminance of the first phosphorescent light emitting material and the wavelength of the highest emission luminance of the second phosphorescent light emitting material is preferably within plus or minus 20 nm.
As described above, the first light-emitting layer and the second light-emitting layer emit light of the same color, but the difference between the wavelengths is within ± 20 nm.

In the present invention, the organic thin film layer preferably has an electron injection layer between the cathode and the organic 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 the 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 above formula, Ar ¹⁷ , Ar ¹⁸ , Ar ¹⁹ , Ar ²¹ , Ar ²² and Ar ²⁵ each represent an aryl group with or without a substituent, Ar ¹⁷ and Ar ¹⁸ , Ar ¹⁹ and Ar ²¹ , 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.
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 above formula (B), X represents a carbon atom or a nitrogen atom. Z ₁ and Z ₂ each independently represents an atomic group capable of forming a nitrogen-containing heterocycle.

Preferably, the organic compound which has a nitrogen-containing aromatic polycyclic group which consists of a 5-membered ring or a 6-membered ring. 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) It is.
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 said formula (2)-(24), R is a C6-C40 aryl group, a C3-C40 heteroaryl group, a C1-C20 alkyl group, or a C1-C20 alkoxy group. And n is an integer of 0 to 5, and when n is an integer of 2 or more, the 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 above 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. And 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 above 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. Or a heteroaryl group having 3 to 40 carbon atoms.
In Ar ¹ represented by the above formula, R ^{1 to} R ⁸ are each a nitrogen-containing heterocyclic derivative that is a hydrogen atom.

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

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

  Further, examples of the nitrogen-containing heterocyclic derivative include compounds represented by the following formulas (201) to (203).

In formulas (201) to (203), R has a hydrogen atom, an aryl group having 6 to 60 carbon atoms which may have a substituent, a pyridyl group which may have a substituent, or a substituent. An optionally substituted quinolyl group, an optionally substituted alkyl group having 1 to 20 carbon atoms, or an optionally substituted alkoxy group having 1 to 20 carbon atoms, and n is 0 to 4 And an integer
R ¹ is chromatic optionally substituted aryl group having 6 to 60 carbon atoms, which may have a substituent group a pyridyl group which may have a substituent quinolyl group, a substituent An optionally substituted alkyl group having 1 to 20 carbon atoms or an alkoxy group having 1 to 20 carbon atoms,
R ² and R ³ each independently have a hydrogen atom, an aryl group having 6 to 60 carbon atoms which may have a substituent, a pyridyl group which may have a substituent, or a substituent. An optionally substituted quinolyl group, an optionally substituted alkyl group having 1 to 20 carbon atoms, or an optionally substituted alkoxy group having 1 to 20 carbon atoms,
L has an arylene group having 6 to 60 carbon atoms which may have a substituent, a pyridinylene group which may have a substituent, a quinolinylene group which may have a substituent or a substituent. A fluorenylene group which may be
Ar ¹ is an arylene group having 6 to 60 carbon atoms which may have a substituent, a pyridinylene group which may have a substituent, or a quinolinylene group which may have a substituent,
Ar ² has an aryl group having 6 to 60 carbon atoms which may have a substituent, a pyridyl group which may have a substituent, a quinolyl group which may have a substituent, and a substituent. It is a C1-C20 alkyl group which may have, or a C1-C20 alkoxy group which may have a substituent.
Ar ³ has an aryl group having 6 to 60 carbon atoms that may have a substituent, a pyridyl group that may have a substituent, a quinolyl group that may have a substituent, and a substituent. An optionally substituted alkyl group having 1 to 20 carbon atoms, an optionally substituted alkoxy group having 1 to 20 carbon atoms, or a group represented by —Ar ¹ —Ar ² (Ar ¹ and Ar ² Are the same as defined above (—Ar ³ = —Ar ¹ —Ar ² )).
Furthermore, as a substituent of Ar < ¹ >, Ar < ² >, Ar < ³ >, a C6-C20 aryl group, a pyridyl group, a quinolyl group, and an alkyl group are preferable.
In addition, when L and Ar ¹ are asymmetric, either of the substitution positions of Ar ¹ and Ar ² bonded to L and Ar ¹ may be selected.

Since the nitrogen-containing heterocyclic derivatives represented by the formulas (201) to (203) are excellent in electron injecting property, the voltage of the organic EL element can be lowered by incorporating them in the electron transporting layer.
Further, since the electron injection property can be improved, a sufficient amount of electrons can be injected into the light emitting layer, so that it is not necessary to block holes by the electron transport layer and confine them in the light emitting layer. For this reason, as in the conventional electron injecting / transporting layer (meaning at least one of the electron injecting layer and the transporting layer) formed of BAlq or the like, holes are emitted from the light emitting layer and the electron injecting / transporting layer. Thus, the lifetime of the organic EL element can be greatly improved.

  In the formulas (201) to (203), R represents a hydrogen atom, an aryl group having 6 to 60 carbon atoms which may have a substituent, a pyridyl group which may have a substituent, or a substituent. A quinolyl group which may have a group, an alkyl group having 1 to 20 carbon atoms which may have a substituent, or an alkoxy group which has 1 to 20 carbon atoms which may have a substituent.

  The aryl group having 6 to 60 carbon atoms is preferably an aryl group having 6 to 40 carbon atoms, more preferably an aryl group having 6 to 20 carbon atoms, specifically, a phenyl group, a naphthyl group, an anthryl group, or phenanthryl. 1 consisting of a group, naphthacenyl group, chrycenyl group, pyrenyl group, biphenyl group, terphenyl group, tolyl group, t-butylphenyl group, (2-phenylpropyl) phenyl group, fluoranthenyl group, fluorenyl group, spirobifluorene A monovalent group consisting of a valent group, a perfluorophenyl group, a perfluoronaphthyl group, a perfluoroanthryl group, a perfluorobiphenyl group, 9-phenylanthracene, and a monovalent group consisting of 9- (1′-naphthyl) anthracene A monovalent group consisting of a group, 9- (2′-naphthyl) anthracene, 6-phenylchrysene A monovalent group consisting of 9- [4- (diphenylamino) phenyl] anthracene, and the like. Phenyl group, naphthyl group, biphenyl group, terphenyl group, 9- (10-phenyl) An anthryl group, 9- [10- (1′-naphthyl)] anthryl group, 9- [10- (2′-naphthyl)] anthryl group and the like are preferable.

As the alkyl group having 1 to 20 carbon atoms, an alkyl group having 1 to 6 carbon atoms is preferable. Specifically, in addition to a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and the like, trifluoro Examples thereof include a haloalkyl group such as a methyl group, and those having 3 or more carbon atoms may be linear, cyclic or branched.
As a C1-C20 alkoxy group, a C1-C6 alkoxy group is preferable, and a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group etc. are mentioned specifically ,. Those having 3 or more carbon atoms may be linear, cyclic or branched.

Examples of the substituent for each group represented by R include a halogen atom, an optionally substituted alkyl group having 1 to 20 carbon atoms, an optionally substituted alkoxy group having 1 to 20 carbon atoms, A C6-C40 aryloxy group which may have a substituent, a C6-C40 aryl group which may have a substituent, or a C3-C3 which may have a substituent 40 heteroaryl groups and the like can be mentioned.
Examples of the halogen atom include fluorine, chlorine, bromine and iodine.
Examples of the alkyl group having 1 to 20 carbon atoms, the alkoxy group having 1 to 20 carbon atoms, and the aryl group having 6 to 40 carbon atoms are the same as those described above.

Examples of the aryloxy group having 6 to 40 carbon atoms include a phenoxy group and a biphenyloxy group.
Examples of the heteroaryl group having 3 to 40 carbon atoms include pyrrolyl group, furyl group, thienyl group, silolyl group, pyridyl group, quinolyl group, isoquinolyl group, benzofuryl group, imidazolyl group, pyrimidyl group, carbazolyl group, selenophenyl group Oxadiazolyl group, triazolyl group and the like.
n is an integer of 0 to 4, preferably 0 to 2.

In Formula (201), R ¹ may have an aryl group having 6 to 60 carbon atoms which may have a substituent, a pyridyl group which may have a substituent, or a substituent. They are a quinolyl group, an optionally substituted alkyl group having 1 to 20 carbon atoms or an alkoxy group having 1 to 20 carbon atoms.
Specific examples of these groups, preferred carbon numbers and substituents are the same as those described for R.

In the formulas (202) and (203), R ² and R ³ each independently have a hydrogen atom, an aryl group having 6 to 60 carbon atoms which may have a substituent, or a substituent. May be a pyridyl group, an optionally substituted quinolyl group, an optionally substituted alkyl group having 1 to 20 carbon atoms, or an optionally substituted group having 1 to 20 carbon atoms. An alkoxy group;
Specific examples of these groups, preferred carbon numbers and substituents are the same as those described for R.

In the above formulas (201) to (203), L has an optionally substituted arylene group having 6 to 60 carbon atoms, an optionally substituted pyridinylene group, and a substituent. It may be a quinolinylene group or a fluorenylene group which may have a substituent.
The arylene group having 6 to 60 carbon atoms is preferably an arylene group having 6 to 40 carbon atoms, more preferably an arylene group having 6 to 20 carbon atoms, specifically, a hydrogen atom 1 from the aryl group described above for R. And divalent groups formed by removing the individual. The substituent for each group represented by L is the same as that described for R.

  L is

A group selected from the group consisting of
In Formula (201), Ar ¹ may have an arylene group having 6 to 60 carbon atoms which may have a substituent, a pyridinylene group which may have a substituent, or a substituent. It is a quinolinylene group. Substituents for each group represented by Ar ¹ and Ar ³ are the same as those described for R.
Ar ¹ is preferably any group selected from fused ring groups represented by the following formulas (101) to (110).

In the formulas (101) to (110), each condensed ring has a halogen atom, an optionally substituted alkyl group having 1 to 20 carbon atoms, and an optionally substituted carbon number 1. Having an alkoxy group of -20, an aryloxy group having 6 to 40 carbon atoms which may have a substituent, an aryl group having 6 to 40 carbon atoms which may have a substituent, or a substituent. Bonding groups consisting of heteroaryl groups having 3 to 40 carbon atoms may be bonded, and when there are a plurality of the bonding groups, the bonding groups may be the same as or different from each other. Specific examples of these groups are the same as those described above.
In the formula (110), L ′ represents a single bond, or

A group selected from the group consisting of
The formula (103) represented by Ar ¹ is preferably a condensed ring group represented by the following formulas (111) to (125).

  In the formulas (111) to (125), each condensed ring has a halogen atom, an optionally substituted alkyl group having 1 to 20 carbon atoms, and an optionally substituted carbon number 1. Having an alkoxy group of -20, an aryloxy group having 6 to 40 carbon atoms which may have a substituent, an aryl group having 6 to 40 carbon atoms which may have a substituent, or a substituent. Bonding groups consisting of heteroaryl groups having 3 to 40 carbon atoms may be bonded, and when there are a plurality of the bonding groups, the bonding groups may be the same as or different from each other. Specific examples of these groups are the same as those described above.

In the above formula (201), Ar ² may have an optionally substituted aryl group having 6 to 60 carbon atoms, an optionally substituted pyridyl group, and an optionally substituted group. A quinolyl group, an optionally substituted alkyl group having 1 to 20 carbon atoms, or an optionally substituted alkoxy group having 1 to 20 carbon atoms.
Specific examples of these groups, preferred carbon numbers and substituents are the same as those described for R.

In the formulas (202) and (203), Ar ³ has an aryl group having 6 to 60 carbon atoms which may have a substituent, a pyridyl group which may have a substituent, and a substituent. An optionally substituted quinolyl group, an optionally substituted alkyl group having 1 to 20 carbon atoms, an optionally substituted alkoxy group having 1 to 20 carbon atoms, or —Ar ¹ —Ar ^2. (Ar ¹ and Ar ² are each the same as described above).
Specific examples of these groups, preferred carbon numbers and substituents are the same as those described for R.
Ar ³ is preferably any group selected from fused ring groups represented by the following formulas (126) to (135).

In the formulas (126) to (135), each condensed ring has a halogen atom, an optionally substituted alkyl group having 1 to 20 carbon atoms, and an optionally substituted carbon number 1. Having an alkoxy group of -20, an aryloxy group having 6 to 40 carbon atoms which may have a substituent, an aryl group having 6 to 40 carbon atoms which may have a substituent, or a substituent. Bonding groups consisting of heteroaryl groups having 3 to 40 carbon atoms may be bonded, and when there are a plurality of the bonding groups, the bonding groups may be the same as or different from each other. Specific examples of these groups are the same as those described above.
In the formula (135), L ′ is the same as described above.
In the above formulas (126) to (135), R ′ is a hydrogen atom, an optionally substituted alkyl group having 1 to 20 carbon atoms, or an optionally substituted group having 6 to 40 carbon atoms. Or a heteroaryl group having 3 to 40 carbon atoms which may have a substituent. Specific examples of these groups are the same as those described above.
The general formula (128) represented by Ar ³ is preferably a condensed ring group represented by the following formulas (136) to (158).

In the above formulas (136) to (158), each condensed ring has a halogen atom, an optionally substituted alkyl group having 1 to 20 carbon atoms, and an optionally substituted carbon number 1 Having an alkoxy group of -20, an aryloxy group having 6 to 40 carbon atoms which may have a substituent, an aryl group having 6 to 40 carbon atoms which may have a substituent, or a substituent. Bonding groups consisting of heteroaryl groups having 3 to 40 carbon atoms may be bonded, and when there are a plurality of the bonding groups, the bonding groups may be the same as or different from each other. Specific examples of these groups are the same as those described above. R ′ is the same as described above.
Ar ² and Ar ³ are each independently

A group selected from the group consisting of
Specific examples of the nitrogen-containing heterocyclic derivative represented by the above formulas (201) to (203) of the present invention are shown below, but the present invention is not limited to these exemplified compounds.
In the table below, HAr represents the formulas (201) to (203).

Indicates. In addition, in the exemplary compounds shown below, exemplary compounds 1-1 to 1-17, 2-1 to 2-9, 3-1 to 3-6, 4-1 to 4-12, 5-1 to 5-6 , 6-1 to 6-5, 8-1 to 8-13 correspond to the above formula (201), and exemplary compounds 9-1 to 9-17, 10-1 to 10-9, 11-1 to 11- 6,12-1 to 12-11,13-1 to 13-6,14-1 to 14-5 correspond to the formula (202), and exemplified compounds 7-1 to 7-10 and 15-1 to 15 -13, 16-1 to 16-8, 17-1 to 17-8 correspond to the formula (203).

  Among the above specific examples, in particular, (1-1), (1-5), (1-7), (2-1), (3-1), (4-2), (4-6) , (7-2), (7-7), (7-8), (7-9), and (9-7) are preferable.

  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.

  The organic EL material-containing solution of the present invention is an organic EL material-containing solution for forming the above-described light-emitting layer, wherein the first polycyclic fused aromatic compound, the first phosphorescent light-emitting material, Is dissolved in a solvent. An organic EL material-containing solution for forming the organic layer, wherein the second polycyclic condensed aromatic compound and the second phosphorescent material are dissolved in a solvent. Features.

In the formation of the organic layer, when the second phosphorescent light emitting material is not included, the second phosphorescent light emitting material is not included.
According to these organic EL material-containing solutions, the above-described mixed color light emitting layer can be formed easily and at low cost by a coating method such as an ink printing method or a nozzle jet method.
Examples of the solvent for these organic EL material-containing solutions include alcohols such as methanol and ethanol, carboxylic acid esters such as ethyl acetate and propyl acetate, nitriles such as acetonitrile, ethers such as isopropyl ether and THF, cyclohexyl, and the like. Examples thereof include aromatic hydrocarbons such as benzene, toluene and xylene, alkyl halides such as methylene chloride, saturated hydrocarbons such as heptane, biphenyl derivatives, and cyclic ketones.

Examples of the biphenyl derivative include alkyl-substituted biphenyl, and specific examples thereof include methylbiphenyl, ethylbiphenyl, diethylbiphenyl, isopropylbiphenyl, diisopropylbiphenyl, n-propylbiphenyl, n-pentylbiphenyl, methoxybiphenyl, and the like. Can be mentioned.
In addition, as for carbon number of the alkyl group of alkyl substituted biphenyl, it is more preferable that it is 1-5. In this case, it is possible to achieve both appropriate viscosity and solubility. For example, ethyl biphenyl, isopropyl biphenyl, and the like can be suitably used as the solvent for the organic EL material-containing solution of the present invention.

The solvent composition may be 100% biphenyl derivative, or a mixed solution in which a viscosity adjusting liquid or the like is mixed.
In the case of a mixed solution, 20% or more may be a biphenyl derivative, 50% or more may be a biphenyl derivative, and 75% or more may be a biphenyl derivative. From the viewpoint of taking advantage of the viscosity and solubility of the biphenyl derivative, a higher proportion of the biphenyl derivative is preferable.

Examples of the cyclic ketone include cyclic alkyl ketones such as a cyclopentanone derivative, a cyclohexanone derivative, a cycloheptanone derivative, and a cyclooctanone derivative. These cyclic ketones may be used alone as a solvent, or may be used as a mixture. In particular, the solvent preferably contains a cyclohexanone derivative as a cyclic ketone.
Preferred cyclohexanone derivatives include 2-acetylcyclohexanone, 2-methylcyclohexanone, 3-methylcyclohexanone, 4-methylcyclohexanone, 2-cyclohexylcyclohexanone, 2- (1-cyclohexenyl) cyclohexanone, 2,5-dimethylcyclohexanone, 3, 4-dimethylcyclohexanone, 3,5-dimethylcyclohexanone, 4-ethylcyclohexanone, pulegone, menthone, 4-pentylcyclohexanone, 2-propylcyclohexanone, 3,3,5-trimethylcyclohexanone, Tujon. Of these, cyclohexanone is preferred.

Further, as the cyclic ketone, those containing a nitrogen-containing ring are also preferable. For example, caprolactam, N-methylcaprolactam, 1,3-dimethyl-2-imidazolidine, 2-pyrrolidone, 1-acetyl-2-pyrrolidone, 1- Examples include butyl-2-pyrrolidone, 2-piperidone, 1,5-dimethyl-2-piperidone.
The cyclic ketone compound is preferably selected from the group of cyclohexanone, cyclopentanone, and cycloheptanone (including these derivatives).

As a result of various studies, the inventors have found that a cyclohexanone derivative dissolves a low-molecular organic EL material at a higher concentration than other solvents, and the soluble compounds are not limited to a narrow range, and a wide variety of low-molecular compounds It has been found that an organic EL material-containing solution using an organic EL material can be prepared.
Then, by using a cyclohexanone derivative as a solvent, an organic EL material-containing solution containing a sufficient amount of a high-performance low-molecular organic EL material that could not be used due to low solubility in conventional solvents was prepared. I found out that I can do it.
Furthermore, since the cyclohexanone derivative has a high boiling point (156 ° C .: cyclohexanone) and a high viscosity (2 cP: cyclohexanone), it is suitable for a coating process such as an inkjet method. And since the cyclohexanone derivative is well mixed with an alcohol solvent as a viscosity adjusting liquid, particularly a diol solvent, it can be made into a high viscosity solution by adjusting the viscosity. This is also an excellent advantage as a solvent for a low-molecular organic EL material that does not change.

(Configuration of organic EL element)
Hereinafter, the element configuration of the organic EL element will be described.
(1) Configuration of Organic EL Element FIG. 1 shows a schematic configuration of the organic EL element of this embodiment.
The organic EL element 1 includes a transparent substrate 2, an anode 3, at least one of a hole injection layer and a transport layer (hereinafter referred to as a hole injection / transport layer) 4, a light emitting layer 5, an organic layer 6, an electron injection layer 7, and a cathode 8.
The hole injection / transport layer 4 and the electron injection layer 7 may not be provided.
Further, an electron barrier layer may be provided on the anode 3 side of the light emitting layer 5. Thereby, it is possible to confine electrons in the light emitting layer 5 and increase the probability of exciton generation in the light emitting layer 5.

(2) Substrate 2
The substrate 2 is a substrate that supports the organic EL element, and is preferably a smooth substrate having a light transmittance in the visible region of 400 to 700 nm of 50% or more. As a specific example of the material of the substrate 2, glass or the like can be applied.

(3) Anode 3
The anode 3 plays a role of injecting holes into the hole injection / transport layer 4 or the light emitting layer 5, and it is effective to have a work function of 4.5 eV or more. Specific examples of the anode material include indium tin oxide alloy (ITO), tin oxide (NESA), indium zinc oxide, gold, silver, platinum, copper, and the like.

(4) Hole injection / transport layer 4
The hole injection / transport layer 4 is a layer that is provided between the light emitting layer 5 and the anode 3, assists hole injection into the light emitting layer 5, and transports it to the light emitting region. Examples of the hole injection / transport layer 4 include 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (hereinafter abbreviated as NPD).
In addition, as a specific example of the hole injection / transport material (meaning at least one of the hole injection material and the transport material), a triazole derivative (see US Pat. No. 3,112,197, etc.) ), Oxadiazole derivatives (see US Pat. No. 3,189,447), imidazole derivatives (see Japanese Patent Publication No. 37-16096), polyarylalkane derivatives (US Pat. No. 3,615,402) 3,820,989, 3,542,544, JP-B-45-555, 51-10983, JP-A-51-93224, 55- No. 17105, No. 56-4148, No. 55-108667, No. 55-156953, No. 56-36656, etc.), pyrazoline derivatives and the like 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 (US patents) No. 3,615,404, Japanese Patent Publication Nos. 51-10105, 46-3712, 47-25336, Japanese Patent Laid-Open Nos. 54-53435, 54-11536, 54 -119925), arylamine derivatives (US Pat. Nos. 3,567,450 and 3,180,703) No. 3,240,597, No. 3,658,520, No. 4,232,103, No. 4,175,961, No. 4,012. , 376, JP-B-49-35702, JP-A-39-27577, JP-A-55-144250, JP-A-56-119132, JP-A-56-22437, West German Patent No. 1,110 , 518, etc.), amino-substituted chalcone derivatives (see US Pat. No. 3,526,501 etc.), oxazole derivatives (disclosed in US Pat. No. 3,257,203 etc.), Styryl anthracene derivatives (see JP-A-56-46234, etc.), fluorenone derivatives (see JP-A-54-110837, etc.), hydrazone derivatives (US Pat. No. 3,717,46) No. 2, JP-A-54-59143, 55-52063, 55-52064, 55-46760, 55-85495, 57-11350, 57-148749, JP-A-2-315991, etc.), stilbene derivatives (JP-A-61-210363, JP-A-61-222851, JP-A-61-14622, JP-A-61-72255) 62-47646, 62-36674, 62-10652, 62-30255, 60-93455, 60-94462, 60-174749, No. 60-175052), silazane derivatives (US Pat. No. 4,950,950), polysilanes (Japanese Patent Laid-Open No. -204996 discloses), aniline copolymers (JP-A-2-282263), an electroconductive oligomer (particularly a thiophene oligomer disclosed in JP-A-1-211399) and the like.

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, 54-149634, 54-64299, 55-79450, 55- 144250, JP-A-56-119132, JP-A-61-295558, JP-A-61-98353, and JP-A-63-295695), 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- () in which three triphenylamine units described in JP-A-4-308688 are linked in a starburst type. 3-methylphenyl) -N-phenylamino) triphenylamine (hereinafter abbreviated as MTDATA) and the like.
In addition, inorganic compounds such as p-type Si and p-type SiC can also be used as the hole injection material. 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.

(5) Light emitting layer 5
For the light emitting layer 5, the above-mentioned polycyclic fused aromatic compound can be used. In addition, the above-described materials can be used as the first phosphorescent material. The polycyclic fused aromatic compound and the first phosphorescent material are dissolved in the aforementioned solvent and used as an organic EL material-containing solution.

(6) Organic layer 6
For the organic layer 6, the aforementioned polycyclic fused aromatic compound having a higher ionization potential than the polycyclic fused aromatic compound used for the light emitting layer 5 can be used. Further, as the second phosphorescent light emitting material, the above-described materials can be used. The second phosphorescent material may be the same as or different from the first phosphorescent material.

(7) Electron injection layer 7
The electron injection layer 7 is a layer that assists injection of electrons into the organic layer 6 or the light emitting layer 5. The electron injection layer and the electron transport layer may be formed together. As the electron injection layer 7, the above-described materials can be used.

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.

(8) Cathode 8
Examples of the cathode include aluminum.

(Manufacturing method of organic EL element)
The organic EL element 1 is manufactured by forming the anode 3, the hole injection / transport layer 4, the light emitting layer 5, the organic layer 6, the electron injection layer 7, and the cathode 8 on the substrate 2 using the materials exemplified above. be able to. Moreover, an organic EL element can also be produced from the cathode to the anode in the reverse order. A production example is described below.

In producing the organic EL element 1, a thin film made of an anode material is first formed on a substrate 2 having an appropriate translucency by a method such as vapor deposition or sputtering so that the film thickness is 1 μm or less, preferably 10 to 200 nm. The anode 3 is formed by forming.
Next, a hole injection / transport layer 4 is provided on the anode 3. The hole injection / transport layer 4 can be formed by a method such as a vacuum deposition method, a spin coating method, a casting method, or an LB method. It is preferable to select appropriately in the thickness range of 5 nm to 5 μm.

  Next, the formation of the light emitting layer 5 provided on the hole injection / transport layer 4 is performed by a dry process represented by a vacuum deposition method using a desired organic light emitting material, or a wet process such as a spin coating method or a casting method. It can be formed by thinning the organic light emitting material. The thickness of the light emitting layer 5 is preferably formed in the range of 5 nm to 40 nm.

Next, the organic layer 6 is provided on the light emitting layer 5. The organic layer 6 can be formed by the same method as that for the light emitting layer 5. The thickness of the organic layer is preferably formed in the range of 5 nm to 40 nm.
The combined thickness of the light emitting layer 5 and the organic layer 6 is 10 nm or more and 80 nm or less, more preferably 10 nm or more and 50 nm or less.

  Then, an electron injection layer 7 is provided on the organic layer 6. The electron injection layer 7 can be formed by the same method as the hole injection / transport layer 4. The thickness of the electron injection layer 7 is preferably selected as appropriate in the range of 5 nm to 5 μm.

  Finally, the cathode 8 can be laminated to obtain the organic EL element 1. The cathode 8 is made of metal, and vapor deposition or sputtering can be used. However, vacuum deposition is preferred to protect the underlying organic layer from damage during film formation.

The formation method of each layer of the organic EL element 1 is not particularly limited.
Conventionally known methods such as vacuum deposition and spin coating can be used. That is, the organic thin film layer can be formed by vacuum deposition, molecular beam deposition (MBE), solution dipping in a solvent, spin It can be formed by a known method such as a coating method, a casting method, a bar coating method, a roll coating method, or an ink jet method.
The film thickness of each organic layer of the organic EL element 1 is not particularly limited, but generally, if the film thickness is too thin, defects such as pinholes are likely to occur. Usually, the range of several nm to 1 μm is preferable.

It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
For example, in the present embodiment, the second phosphorescent material is included in the organic layer, but an organic layer that does not include the second phosphorescent material may be used.

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 to the description content of these Examples at all.
<Test 1>
First, the effectiveness of the organic layer was tested.

[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, and then UV ozone cleaning was performed for 30 minutes.
The glass substrate with the transparent electrode line after the cleaning is mounted on the substrate holder of the vacuum evaporation apparatus, and first, 4,4 ′ having a thickness of 50 nm is formed on the surface where 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 light emitting layer is formed on the NPD film. As a phosphorescent host, the following compound (H1) was formed into a film with a thickness of 40 nm by resistance heating vapor deposition. At the same time, the following compound (D1) (Ir (ppy) ₃ ) was deposited as a phosphorescent light-emitting material so as to have a mass ratio of 5% with respect to the compound (H1). This film functions as a phosphorescent light emitting layer.
Subsequently, an organic layer is formed on the phosphorescent light emitting layer. The following compound (H2) was formed to a thickness of 10 nm. This organic layer functions as a hole blocking layer.
Further, the following compound J was formed on this film with a film thickness of 40 nm. This functions as an electron injection layer.
Thereafter, LiF was deposited at 1 nm. A metal cathode was formed by vapor-depositing metal Al on this LiF film to form an organic EL light emitting device.

[Example 2]
An organic EL device was produced in the same manner as in Example 1 except that the following compound (H3) was used as the organic layer.

[Comparative Example 1]
An organic EL device was produced in the same manner as in Example 1 except that Balq (bis- (2-methyl-8-quinolinolate) -4- (phenylphenolate) aluminum) was used as the organic layer.

[Evaluation of organic EL elements]
The organic EL element produced as described above was caused to emit light by a direct current of 1 mA / cm ² and the emission chromaticity and voltage were measured. Further, a half-life of each organic EL element was measured by performing a continuous DC current test with an initial luminance of 5000 cd / m ² .
The results are shown in Table 1 below.

As is clear from Table 1, the organic EL elements of Examples 1 and 2 have a long lifetime.
On the other hand, in Comparative Example 1 using Balq that has been conventionally used as a hole barrier layer, the lifetime is short.

<Test 2>
Next, evaluation was performed when a phosphorescent material was included in the organic layer.
[Example 3]
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 the cleaning is mounted on the substrate holder of the vacuum evaporation apparatus, and first, 4,4 ′ having a thickness of 50 nm is formed on the surface where 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 light emitting layer is formed on the NPD film. The compound represented by the compound (H1) was formed into a film with a thickness of 20 nm by resistance heating vapor deposition. At the same time, the compound represented by the above formula (D1) was deposited as a phosphorescent material so that the mass ratio was 5% with respect to the compound (H1).
Further, an organic layer is formed on the light emitting layer. The compound represented by the above formula (H2) was formed into a film with a thickness of 20 nm by resistance heating vapor deposition. At the same time, the compound represented by the above formula (D1) was deposited as a phosphorescent material so that the mass ratio was 5% with respect to the compound (H2).

And the following compound J was formed into a film with a film thickness of 40 nm on this organic layer. This functions as an electron injection layer.
Thereafter, LiF was deposited at 1 nm. A metal cathode was formed by vapor-depositing metal Al on this LiF film to form an organic EL light emitting device.

[Example 4]
An organic EL device was produced in the same manner as in Example 1 except that the compound (H3) was used instead of the compound (H2) used in the organic layer.

[Comparative Example 2]
An organic EL device was produced in the same manner as in Example 1 except that the organic layer was not provided.

[Comparative Example 3]
An organic EL element was produced in the same manner as in Example 1 except that the light emitting layer was not provided.

[Comparative Example 4]
An organic EL element was produced in the same manner as in Example 2 except that the light emitting layer was not provided and the film thickness was not provided. In Comparative Example 4, the thickness of the light emitting layer was 20 nm, and the thickness of the organic layer was 20 nm.

[Evaluation of organic EL elements]
A direct current was passed through the organic EL elements produced in Examples 3 and 4 and Comparative Examples 2 to 4 to emit light, and the emission chromaticity and voltage were measured. 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 Table 2 below, and the triplet energy gap Eg (T) of the compounds (H1) to (H3) is shown in Table 3 below.

As is clear from Table 2, Examples 3 and 4 having a light emitting layer and an organic layer using different polycyclic fused aromatic compounds have a long lifetime.
On the other hand, Comparative Example 2 has a significantly shorter life than Examples 3 and 4.

  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 Hole injection / transport layer 5 Light emitting layer 6 Organic layer 7 Electron injection layer 8 Cathode

Claims (18)

An anode, a cathode, and an organic thin film layer provided between the anode and the cathode,
The organic thin film layer is
A light emitting layer having a first polycyclic fused aromatic compound having a substituted or unsubstituted polycyclic fused aromatic skeleton, and a first phosphorescent material that exhibits phosphorescence; and
An organic layer containing a second polycyclic fused aromatic compound having a substituted or unsubstituted polycyclic fused aromatic skeleton on the cathode side of the light emitting layer. EL element. The organic EL device according to claim 1,
At least one of the first polycyclic fused aromatic compound and the second polycyclic fused aromatic compound has a lowest excited triplet energy gap of 2.1 eV or more and 2.7 eV or less. And the number of nucleus atoms of the said polycyclic condensed aromatic skeleton part is 10-30. The organic EL element characterized by the above-mentioned. The organic EL device according to claim 1 or 2,
An organic EL device, wherein the ionization potential of the second polycyclic fused aromatic compound is greater than the ionization potential of the first polycyclic fused aromatic compound. In the organic EL element according to any one of claims 1 to 3,
The lowest excited triplet energy gap Eg (T2) of the second polycyclic fused aromatic compound is larger than the lowest excited triplet energy gap Eg (T1) of the first polycyclic fused aromatic compound. An organic EL element characterized by the above. In the organic EL element according to any one of claims 1 to 4,
The organic layer contains a second phosphorescent material that emits phosphorescence. In the organic EL element according to any one of claims 1 to 4,
The organic layer contains the first phosphorescent material. The organic EL device, wherein: In the organic EL element according to any one of claims 1 to 6,
The organic EL device, wherein the polycyclic fused aromatic skeleton is contained in the chemical structural formula as a divalent or higher valent group. In the organic EL element according to any one of claims 1 to 6,
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. The organic EL element according to claim 8,
The organic EL device, wherein a substituent of the polycyclic fused aromatic skeleton is excluded from those having a carbazole skeleton. The organic EL device according to claim 7,
The polycyclic fused aromatic skeleton is selected from the group of substituted or unsubstituted phenanthrene diyl, chrysenediyl, fluoranthenediyl, and triphenylenediyl. The organic EL device according to claim 10,
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 6,
The polycyclic fused aromatic skeleton is represented by any of the following formulas (1) to (4):

(In Formula (1) to Formula (4), Ar ^{1 to} Ar ⁵ represent a substituted or unsubstituted ring-forming carbon number (not including the carbon number of the substituent) 4 to 10 condensed ring structure.)
An organic EL device characterized by that. In the organic EL device according to any one of claims 1 to 12,
At least one of the first phosphorescent material and the second phosphorescent material is a metal complex composed of a metal selected from Ir, Pt, Os, Au, Cu, Re, and Ru and a ligand. An organic EL device comprising: In the organic EL element according to any one of claims 1 to 13,
The organic phosphor element, wherein the first phosphorescent light emitting material and the second phosphorescent light emitting material have a wavelength of maximum light emission luminance of 470 nm or more and 700 nm or less. In the organic EL element according to any one of claims 1 to 14,
The difference between the maximum emission luminance wavelength of the first phosphorescent light emitting material and the maximum emission luminance wavelength of the second phosphorescent light emitting material is within ± 20 nm. In the organic EL element according to any one of claims 1 to 15,
The organic thin film layer has an electron injection layer between the cathode and the organic layer,
The electron injection layer includes a nitrogen-containing heterocyclic derivative. An organic EL device, wherein: An organic EL material-containing solution for forming the light emitting layer in the organic EL device according to any one of claims 1 to 16,
The organic EL material-containing solution, wherein the first polycyclic fused aromatic compound and the first phosphorescent material are dissolved in a solvent. An organic EL material-containing solution for forming the organic layer in the organic EL element according to any one of claims 5 to 16,
The organic EL material-containing solution, wherein the second polycyclic fused aromatic compound and the second phosphorescent material are dissolved in a solvent.