JP2006100393A - Organic light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic light emitting device with good durability which has high external quantum efficiency. <P>SOLUTION: The organic light emitting device has at least one organic compound layer between a pair of electrodes. The compound is expressed by a general formula (1) containing the organic compound layer. Here, in a general formula (1), R<SP>11</SP>expresses H or a substituent. R<SP>12</SP>and R<SP>14</SP>express H or a substituent independently, respectively. At least one of R<SP>12</SP>and R<SP>14</SP>is an electronic suctional radical. R<SP>13</SP>expresses the alkyl group or aromatic group which at least one F substitutes. Q<SP>11</SP>expresses a group forming a hetero ring containing nitrogen, L<SP>11</SP>expresses a ligand. M<SP>11</SP>expresses the ion of Ir, Re, Pd, or Rh. Z<SP>11</SP>expresses C or N. When Z<SP>11</SP>is C, the interatomic bonding between Z<SP>11</SP>and N atom is double bonding. When Z<SP>11</SP>is N atom, the interatomic bonding between Z<SP>11</SP>and N atom is a single bonding. m<SP>11</SP>expresses the integer of 1-3, and m<SP>12</SP>expresses the integer of 0-4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light-emitting element that can emit light by converting electric energy into light, and particularly relates to an organic electroluminescent element (hereinafter also referred to as “organic EL element”, “light-emitting element”, or “EL element”).

  An organic electroluminescence (EL) element has attracted attention as a promising display element because it can emit light with high luminance at a low voltage. An important characteristic value of this organic electroluminescence device is external quantum efficiency. The external quantum efficiency is calculated by “external quantum efficiency φ = number of photons emitted from the device / number of electrons injected into the device”, and the larger this value, the more advantageous the device in terms of power consumption.

  The external quantum efficiency of the organic electroluminescence device is determined by “external quantum efficiency φ = internal quantum efficiency × light extraction efficiency”. In an organic EL device using fluorescence emission from an organic compound, the limit value of the internal quantum efficiency is 25%, and the light extraction efficiency is approximately 20%. Therefore, the limit value of the external quantum efficiency is approximately 5%. Has been.

Devices that use triplet light-emitting materials (phosphorescent materials) have been reported as a method for improving the internal quantum efficiency of organic electroluminescent devices and improving the external quantum efficiency of the devices. Various studies have been conducted to improve the performance. A light-emitting element in which durability (exciton stability of a light-emitting material) is improved by introducing a specific substituent into the light-emitting material is disclosed (Patent Document 1). However, further improvement in durability has been desired.
International Publication No. 04/016711 Pamphlet

  An object of the present invention is to provide an organic electroluminescent device having good durability.

In view of the above circumstances, the present inventors have conducted extensive research and found that the above-mentioned problems can be solved by using a specific compound in the organic compound layer between a pair of electrodes, and thus completed the present invention.
That is, the present invention is achieved by the following means.

<1> An organic electroluminescent device having at least one organic compound layer including a light emitting layer between a pair of electrodes, wherein the organic compound layer contains a compound represented by the following general formula (1) An organic electroluminescent element.

R ¹¹ represents a hydrogen atom or a substituent. R ¹² and R ¹⁴ each independently represents a hydrogen atom or a substituent, and at least one of R ¹² and R ¹⁴ is an electron-withdrawing group. R ¹³ represents an alkyl group or an aromatic group substituted with at least one fluorine atom. Q ¹¹ represents a group that forms a nitrogen-containing heterocycle, L ¹¹ represents a ligand, and M ¹¹ represents an iridium ion, a rhenium ion, a palladium ion, or a rhodium ion. Z ¹¹ represents a carbon atom or a nitrogen atom. When Z ¹¹ is a carbon atom, the bond between Z ¹¹ and the nitrogen atom is a double bond, and when Z ¹¹ is a nitrogen atom, the bond between Z ¹¹ and the nitrogen atom is a single bond. m ¹¹ represents an integer of 1 to 3, m ¹² represents an integer of 0-4.

<2> The organic electroluminescence device according to <1>, wherein the compound represented by the general formula (1) is a compound represented by the following general formula (2).

R ²¹ represents a hydrogen atom or a substituent. R ²² and R ²⁴ each independently represent a hydrogen atom or a substituent, and at least one of R ²² and R ²⁴ is an electron-withdrawing group. R ²³ represents an alkyl group or an aromatic group substituted with at least one fluorine atom. Q ²¹ represents a group that forms a nitrogen-containing heterocycle, L ²¹ represents a ligand, and M ²¹ represents an iridium ion, a rhenium ion, a palladium ion, or a rhodium ion. m ²¹ represents an integer of 1 to 3, and m ²² represents an integer of 0 to 4.

<3> The organic electroluminescent element as described in <1> or <2> above, wherein the compound represented by the general formula (1) is a compound represented by the following general formula (3).

R ³¹ represents a hydrogen atom or a substituent. Q ³¹ represents a group that forms a nitrogen-containing heterocycle, L ³¹ represents a ligand, and M ³¹ represents an iridium ion, a rhenium ion, a palladium ion, or a rhodium ion. R ³⁵ represents a substituent. m ³¹ represents an integer of 1 to 3, and m ³² represents an integer of 0 to 4. n ³¹ denotes an integer 1 to 5, n ³² represents an integer of 0-4. n ³¹ + n ³² ≦ 5.

<4> The organic compound according to any one of <1> to <3>, wherein the compound represented by the general formula (1) is a compound represented by the following general formula (4): Electroluminescent device.

R ⁴¹ represents a hydrogen atom or a substituent. Q ⁴¹ represents a group that forms a nitrogen-containing heterocycle, L ⁴¹ represents a ligand, and M ⁴¹ represents an iridium ion, a rhenium ion, a palladium ion, or a rhodium ion. m ⁴¹ represents an integer of 1 to 3, m ⁴² represents an integer of 0-4.

  According to the present invention, it is possible to provide a light emitting device having good durability.

[Organic electroluminescence device]
The organic electroluminescent element of the present invention is an organic electroluminescent element having at least one organic compound layer including a light emitting layer between a pair of electrodes, wherein the compound represented by the general formula (1) is converted into the organic compound layer. It is contained in.
The organic electroluminescent device of the present invention can be a light emitting device having excellent driving durability by containing the compound of the general formula (1) in the organic compound layer between a pair of electrodes.
The compound of the general formula (1) may have a function of a hole injection / transport material, a light emitting material, an electron injection / transport material, a host material, or the like, or may have a composite function thereof. Especially, it is preferable to use as a luminescent material.

Next, the structure of the light emitting device of the present invention will be described.
The light-emitting element of the present invention has at least one organic compound layer including a light-emitting layer or a light-emitting layer between a pair of electrodes, and can further have other organic compound layers in addition to the light-emitting layer. Each of these layers may have other functions. Various materials can be used for forming each layer.

Hereinafter, the general formula (1) will be described.
In general formula (1), R ¹¹ represents a hydrogen atom or a substituent.
Examples of the substituent include an alkyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 10 carbon atoms, such as methyl, ethyl, iso-propyl, tert- Butyl, n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc.), an alkenyl group (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms such as vinyl, allyl, 2-butenyl, 3-pentenyl, etc.), alkynyl groups (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms such as propargyl and 3-pentynyl), aryl group (preferably carbon 6 to 30, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenyl, p-methylphenyl, naphthyl, anthranyl, etc.), amino group (preferably 0 carbon atoms) -30, more preferably 0 to 20 carbon atoms, particularly preferably 0 to 10 carbon atoms, such as amino, methylamino, dimethylamino, diethylamino, dibenzylamino, diphenylamino, ditolylamino, etc.), alkoxy Group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 10 carbon atoms, and examples thereof include methoxy, ethoxy, butoxy, 2-ethylhexyloxy and the like), aryl Oxy group (preferably having 6 to 30 carbon atoms, more preferably having 6 to 20 carbon atoms, particularly preferably A prime number of 6 to 12, for example, phenyloxy, 1-naphthyloxy, 2-naphthyloxy, etc.), a heterocyclic oxy group (preferably having a carbon number of 1 to 30, more preferably a carbon number of 1 to 20, particularly Preferably it is C1-C12, for example, pyridyloxy, pyrazyloxy, pyrimidyloxy, quinolyloxy etc.), an acyl group (preferably C1-C30, more preferably C1-C20, especially preferably carbon) 1 to 12, for example, acetyl, benzoyl, formyl, pivaloyl, etc.), an alkoxycarbonyl group (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 2 carbon atoms). 12 such as methoxycarbonyl and ethoxycarbonyl), aryl An oxycarbonyl group (preferably having 7 to 30 carbon atoms, more preferably 7 to 20 carbon atoms, particularly preferably 7 to 12 carbon atoms, and examples thereof include phenyloxycarbonyl. ), An acyloxy group (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms such as acetoxy and benzoyloxy), an acylamino group (preferably 2-30 carbon atoms, more preferably 2-20 carbon atoms, particularly preferably 2-10 carbon atoms, and examples thereof include acetylamino, benzoylamino, and the like, and an alkoxycarbonylamino group (preferably having 2-2 carbon atoms). 30, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonylamino, etc.), aryloxycarbonylamino group (preferably 7 to 30 carbon atoms, more preferably 7 to 20 carbon atoms, particularly preferably 7 to 12 carbon atoms, such as phenyloxycarbonyl And sulfonylamino groups (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms, such as methanesulfonylamino and benzenesulfonylamino). ), A sulfamoyl group (preferably having 0 to 30 carbon atoms, more preferably 0 to 20 carbon atoms, particularly preferably 0 to 12 carbon atoms, such as sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, phenyl Sulfamoyl, etc.), a carbamoyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as carbamoyl, methylcarbamoyl, diethylcarbamoyl, Phenylcarbamoyl etc.), alkylthio group ( Preferably, it has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include methylthio, ethylthio and the like, and an arylthio group (preferably 6 to 30 carbon atoms). , More preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenylthio, etc.), a heterocyclic thio group (preferably 1 to 30 carbon atoms, more preferably 1 to carbon atoms). 20, particularly preferably 1 to 12 carbon atoms, such as pyridylthio, 2-benzimidazolylthio, 2-benzoxazolylthio, 2-benzthiazolylthio and the like, and a sulfonyl group (preferably having a carbon number). 1 to 30, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as mesyl and tosyl). Rufinyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include methanesulfinyl and benzenesulfinyl. ), A ureido group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms, such as ureido, methylureido, phenylureido, etc.), phosphoric acid. An amide group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as diethyl phosphoric acid amide and phenylphosphoric acid amide), a hydroxy group , Mercapto group, halogen atom (eg fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, heterocyclic group ( Preferably it is C1-C30, More preferably, it is C1-C12, As a hetero atom, for example, a nitrogen atom, oxygen Children, sulfur atoms, specifically imidazolyl, pyridyl, quinolyl, furyl, thienyl, piperidyl, morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, carbazolyl group, azepinyl group, etc.), silyl group (preferably). Has 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, particularly preferably 3 to 24 carbon atoms, and examples thereof include trimethylsilyl, triphenylsilyl, and the like, and a silyloxy group (preferably 3 to 40 carbon atoms). More preferably, it has 3 to 30 carbon atoms, particularly preferably 3 to 24 carbon atoms, and examples thereof include trimethylsilyloxy, triphenylsilyloxy, and the like. These substituents may be further substituted.

R ¹¹ is preferably a hydrogen atom, an alkyl group, or a fluorine atom, more preferably a hydrogen atom or a fluorine atom, and even more preferably a hydrogen atom.

R ¹² and R ¹⁴ each independently represents a hydrogen atom or a substituent, and at least one of R ¹² and R ¹⁴ is an electron-withdrawing group.
Examples of the substituent include the groups described for R ¹¹ . Examples of the electron-withdrawing group include a substituent having a negative Hammett σ value (σ _m , σ _p value), such as a fluorine atom, a cyano group, a fluoroalkyl group (a trifluoromethyl group, a pentafluoro group). Ethyl group and the like, and an electron-withdrawing group-substituted phenyl group (perfluorophenyl group, trifluoromethylphenyl group and the like) are preferable, a fluorine atom, a fluoroalkyl group, and a fluorine atom-substituted phenyl group are more preferable, and a fluorine atom is more preferable.

R ¹³ represents an alkyl group or an aromatic group substituted with at least one fluorine atom.
Specifically, an alkyl group substituted with a fluorine atom (preferably, for example, a trifluoromethyl group or a pentafluoroethyl group) or an aromatic group substituted with a fluorine atom on an aromatic ring (preferably perfluorophenyl). Group). The number of fluorine atoms substituted is not limited, but is preferably an alkyl group or an aromatic group, all of which are fluorine-substituted.

Q ¹¹ represents a group that forms a nitrogen-containing heterocycle. Q ^11, and is not particularly restricted but includes the ring structure formed by Z ^11, include nitrogen-containing aromatic five- or six-membered, for example, pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring, pyrrole ring , Pyrazole ring, imidazole ring, triazole ring, thiazole ring, oxazole ring, oxadiazole ring, thiadiazole ring, azaphosphinine ring, condensed rings thereof, and tautomers thereof (for example, benzimidazole ring, Indolenine ring, quinoline ring).

The nitrogen-containing heterocycle formed by Q ¹¹ and Z ¹¹ is a pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring, pyrrole ring, pyrazole ring, imidazole ring, triazole ring, thiazole ring, oxazole ring, oxadiazole A ring, a thiadiazole ring and an azaphosphinine ring are preferred, a pyridine ring, a pyrrole ring, a pyrazole ring and an imidazole ring are more preferred, a pyridine ring, a pyrazole ring and an imidazole ring are more preferred, and a pyridine ring is particularly preferred.

The substituent on Q ¹¹ is not particularly limited, but is preferably an alkyl group, an aryl group, a dialkylamino group, a diarylamino group, an alkoxy group, an aryloxy group, or a silyl group, an alkyl group, a dialkylamino group, a diarylamino group, An alkoxy group is more preferable, and an alkyl group and a dialkylamino group are more preferable.

L ¹¹ represents a ligand. Examples of the ligand include “Photochemistry and Photophysics of Coordination Compounds” by Springer-Verlag H. Published in 1987 by Yersin, “Organometallic Chemistry-Fundamentals and Applications-” The ligands described in “Hanabobo, Akio Yamamoto, published in 1982” and the like, preferably halogen ligands (preferably chlorine coordination) Element, fluorine ligand), nitrogen-containing heterocyclic ligand (eg bipyridyl, phenanthroline, phenylpyridine, pyrazolylpyridine, benzimidazolylpyridine), diketone ligand, nitrile ligand, CO ligand, isonitrile coordination Ligands, phosphorus ligands (eg, phosphine derivatives, phosphite ester derivatives, phosphinin derivatives, etc.), carboxylic acid ligands (eg, acetic acid ligands, etc.), more preferably bidentate nitrogen-containing heterocycles Ligands such as bipyridyl, phenanthroline, phenylpyridine, pyrazolylpyridine, benzimidazolylpyridine, Nirupirazoru, or the like).

M ¹¹ represents an iridium ion, a rhenium ion, a palladium ion, or a rhodium ion. Among them, the valence of iridium ions is preferably trivalent or tetravalent, the valence of rhenium ions is monovalent, the valence of palladium ions is preferably bivalent, the valence of rhodium ions is preferably trivalent, and the valence of iridium ions is 3. The valence of valence and rhenium ions is more preferably monovalent, and the valence of iridium ions is particularly preferably trivalent.

Z ¹¹ represents a carbon atom or a nitrogen atom. When Z ¹¹ is a carbon atom, the bond between Z ¹¹ and the nitrogen atom is a double bond, and when Z ¹¹ is a nitrogen atom, the bond between Z ¹¹ and the nitrogen atom is a single bond. Z ¹¹ is preferably a carbon atom.

m ¹¹ represents an integer of 1 to 3, and preferably 2 or 3. m ¹² represents an integer of 0 to 4, and 0 and 1 are preferable.

The compound represented by the general formula (1) is preferably a compound represented by the general formula (2).
Hereinafter, the general formula (2) will be described.
R ²¹ , R ²² , R ²³ , R ²⁴ , L ²¹ , M ²¹ , m ²¹ , m ²² are R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , L ¹¹ , M ¹¹ , m ¹¹ , m, respectively. ^It is synonymous with ¹² , and the preferred range is also the same.

Q ²¹ represents a group forming a nitrogen-containing heterocycle. No particular limitation is imposed on the ring structure formed by Q ^21, include nitrogen-containing aromatic five- or six-membered, for example, pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring, pyrrole ring, pyrazole ring, imidazole Ring, triazole ring, thiazole ring, oxazole ring, oxadiazole ring, thiadiazole ring, azaphosphinine ring, and their condensed rings and tautomers (for example, benzimidazole ring, indolenine ring, quinoline) Ring).

The nitrogen-containing heterocycle formed by Q ²¹ includes a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a pyrrole ring, a pyrazole ring, an imidazole ring, a triazole ring, a thiazole ring, an oxazole ring, an oxadiazole ring, a thiadiazole ring, Azaphosphinine ring is preferable, pyridine ring, pyrrole ring, pyrazole ring and imidazole ring are more preferable, pyridine ring, pyrazole ring and imidazole ring are further preferable, and pyridine ring is particularly preferable.

The compound represented by the general formula (1) is preferably a compound represented by the general formula (3).
Hereinafter, the general formula (3) will be described. R ³¹ , L ³¹ , M ³¹ , Q ³¹ , m ³¹ and m ³² have the same meanings as R ¹¹ , L ¹¹ , M ¹¹ , Q ²¹ , m ¹¹ and m ¹² , respectively, and the preferred ranges are also the same.

R ³⁵ represents a substituent. Examples of the substituent include the group described for R ¹¹ , and the preferred range is also the same.

n ³¹ denotes an integer 1 to 5, n ³² represents an integer of 0-4. n ³¹ is preferably 3 to 5, more preferably 4, 5, and still more preferably 5. n ³² is preferably 0 or 1, more preferably 0. n ³¹ + n ³² ≦ 5.

The compound represented by the general formula (1) is preferably a compound represented by the general formula (4).
Hereinafter, the general formula (4) will be described.
R ⁴¹ , L ⁴¹ , M ⁴¹ , Q ⁴¹ , m ⁴¹ and m ⁴² are the same as R ¹¹ , L ¹¹ , M ¹¹ , Q ²¹ , m ¹¹ and m ¹² , respectively, and the preferred ranges are also the same. .

  Next, specific examples of the compounds represented by the general formulas (1) to (4) in the present invention are shown, but the present invention is not limited thereto.

Next, a method for synthesizing the compound represented by the general formula (1) will be described. The compound represented by the general formula (1) can be synthesized by a known method described in, for example, International Publication No. 04/016711 pamphlet.
Ligand and metal compound (for example, in the case of iridium complex, trisacetylacetonatoiridium, potassium hexachloroiridate, iridium trichloride, iridium trichloride hydrate, etc.) in a solvent (diethylene glycol, methoxyethanol, glycerol, In addition to water, a mixture thereof, and the like, the mixture can be synthesized by stirring (room temperature to reflux).
The ligand, for example, the ligand of the compound represented by (1-1), is obtained by dissolving 2- (2,4-difluorophenyl) pyridine in THF, cooling to −78 ° C., and then adding LDA (lithium Diisopropylamide) can be added to react with hexafluorobenzene for synthesis.

<Organic compound layer>
The organic compound layer in the light emitting device of the present invention is preferably at least three layers of a hole transport layer and an electron transport layer in addition to the light emitting layer.
The organic compound layer is required to contain the compound represented by the general formula (1), and among them, the organic compound layer is preferably contained in the light emitting layer from the viewpoint of improving the light emission efficiency.
Further, the organic compound layer has a hole injection layer on the anode side of the hole transport layer, an electron injection layer on the cathode side of the electron transport layer, and a hole blocking layer between the light emitting layer and the electron transport layer. Can do. Each layer may be divided into a plurality of secondary layers.

(Formation of organic compound layer)
The formation method of the organic layer containing the compound in the present invention is not particularly limited, but resistance heating vapor deposition, electron beam, sputtering, molecular lamination method, coating method (spray coating method, dip coating method, impregnation method, Roll coating method, gravure coating method, reverse coating method, roll brush method, air knife coating method, curtain coating method, spin coating method, flow coating method, bar coating method, micro gravure coating method, air doctor coating, blade coating method, Squeeze coating method, transfer roll coating method, kiss coating method, cast coating method, extrusion coating method, wire bar coating method, screen coating method, etc.), ink jet method, printing method, transfer method, etc. are used. Resistance heating vapor deposition, coating Law, a transfer method is preferable.
Although the film thickness of an organic compound layer is not specifically limited, Usually, the thing of the range of 1-1000 nm is preferable, More preferably, it is 10-500 nm, More preferably, it is 50-200 nm.

(Light emitting layer)
The light emitting layer in the present invention preferably contains the compound represented by the general formula (1) as a phosphorescent light emitting material, and may further contain other light emitting materials.
As a material for the light-emitting layer, electrons can be injected from the cathode, the electron injection layer, or the electron transport layer together with the function of injecting holes from the anode, the hole injection layer, or the hole transport layer when an electric field is applied. Any known phosphorescent light emitting material may be used as long as it can form a layer having a function, a function of moving injected charges, and a function of emitting light by providing a recombination field of holes and electrons. Fluorescent materials and host materials can be used.
The light emitting layer in the present invention preferably contains a host material together with the compound of the general formula (1) from the viewpoints of luminous efficiency and durability.

-Phosphorescent material-
The compound of the general formula (1) is also used as a phosphorescent material, and the phosphorescent material is a material that emits phosphorescence when a voltage is applied to the organic electroluminescent element. Other typical phosphorescent materials include iridium complexes typified by Ir (ppy) ₃ (trisphenylpyridine iridium complex), platinum complexes typified by PTOEP (octaethylplatinum porphyrin complex), and benzophenone. Non-complex compounds can be used, and can be used as necessary.

  The phosphorescence quantum yield of the phosphorescent material is preferably 30% or more, more preferably 50% or more, further preferably 70% or more, and 90% or more from the viewpoint of light emission efficiency. It is particularly preferred that

The phosphorescence quantum yield of the phosphorescent material is determined by, for example, freezing and degassing a phosphorescent material (for example, a concentration of 1 × 10 ⁻³ mol / l) dissolved in an organic solvent (for example, toluene, dichloroethane, etc.) The amount of luminescence when irradiated with light can be measured by comparing with a material whose absolute fluorescence quantum yield is known (for example, fluorescein, anthracene, rhodamine, etc.).

  The phosphorescence lifetime of the phosphorescent material is preferably 10 μs or less, more preferably 5 μs or less, and even more preferably 3 μs or less from the viewpoints of light emission efficiency and light emission response.

The phosphorescence lifetime of the phosphorescent material is determined by freezing and degassing a phosphorescent material (for example, a concentration of 1 × 10 ⁻³ mol / l) dissolved in an organic solvent (for example, toluene, dichloroethane, etc.) at room temperature. It can be obtained by measuring the light emission lifetime when irradiated with light.

The phosphorescent material (the compound represented by the general formula (1)) has a T ₁ level (lowest triplet excited state energy level) of 60 Kcal / mol or more (251.4 KJ / mol or more), 90 Kcal / mol or less (377.1 KJ / mol or less) is preferable, 62 Kcal / mol or more (259.78 KJ / mol or more), 85 Kcal / mol or less (356.15 KJ / mol or less) is more preferable, 65 More preferably, it is Kcal / mol or more (272.35 KJ / mol or more), 80 Kcal / mol or less (335.2 KJ / mol or less).

  In the present invention, a value calculated from the emission short wavelength end of the phosphorescent material can be used.

  In addition to the above compounds, the light-emitting layer in the present invention includes, for example, benzoxazole, benzimidazole, benzothiazole, styrylbenzene, polyphenyl, diphenylbutadiene, tetraphenylbutadiene, naphthalimide, coumarin, perylene, perinone, oxadiazole, aldazine, Pyraridin, cyclopentadiene, bisstyrylanthracene, quinacridone, pyrrolopyridine, thiadiazopyridine, cyclopentadiene, styrylamine, aromatic dimethylidin compounds, various metal complexes represented by 8-quinolinol metal complexes and rare earth complexes, polythiophene, polyphenylene , Transition compounds represented by polymer compounds such as polyphenylene vinylene, organic silanes, iridium trisphenyl pyridine complexes, and platinum porphyrin complexes Metal complex, and it can be used those derivatives.

-Host material-
Examples of the host material in the light emitting layer in the present invention include nitrogen-containing heterocyclic compounds, aromatic hydrocarbon compounds, metal complexes, organosilicon compounds, and aniline derivatives. A ring compound, a metal complex, and an aromatic hydrocarbon compound are preferable, a nitrogen-containing heterocyclic compound and a metal complex are more preferable, and a nitrogen-containing heterocyclic compound is particularly preferable.

The ionization potential of the host material is preferably 5.8 eV or more and 6.3 eV or less, more preferably 5.95 eV or more and 6.25 eV or less, and 6.0 eV or more from the viewpoint of driving voltage and durability. More preferably, it is 6.2 eV or less.
As the ionization potential, a value measured by AC-1 (manufactured by Riken Keiki Co., Ltd.) can be used.

The electron mobility of the host material is preferably 1 × 10 ⁻⁶ Vs / cm or more and 1 × 10 ⁻¹ Vs / cm or less from the viewpoint of driving voltage, and is preferably 5 × 10 ⁻⁶ Vs / cm or more and 1 ×. More preferably, it is 10 ⁻² Vs / cm or less, more preferably 1 × 10 ⁻⁵ Vs / cm or more and 1 × 10 ⁻² Vs / cm or less, and more preferably 5 × 10 ⁻⁵ Vs / cm or more and 1 ×. It is particularly preferably 10 ⁻² Vs / cm or less.
As the electron mobility of the host material, a value measured by a time-of-flight method can be used.

The hole mobility of the host material is preferably 1 × 10 ⁻⁶ Vs / cm or more and 1 × 10 ⁻¹ Vs / cm or less from the viewpoint of drive voltage, and is preferably 5 × 10 ⁻⁶ Vs / cm or more and 1 ×. It is more preferably 10 ⁻² Vs / cm or less, further preferably 1 × 10 ⁻⁵ Vs / cm or more and 1 × 10 ⁻² Vs / cm or less, more preferably 5 × 10 ⁻⁵ Vs / cm or more and 1 ×. It is particularly preferably 10 ⁻² Vs / cm or less.
As the electron mobility of the host material, a value measured by a time-of-flight method can be used.

The T ₁ level (minimum triplet excited state energy level) of the host material in the light emitting layer is 60 Kcal / mol or more (251.4 KJ / mol or more), 90 Kcal / mol or less (377.1 KJ / mol or less). ), Preferably 62 Kcal / mol or more (259.78 KJ / mol or more), 85 Kcal / mol or less (356.15 KJ / mol or less), more preferably 65 Kcal / mol or more (272.35 KJ / mol or more). ), 80 Kcal / mol or less (335.2 KJ / mol or less).
As the T ₁ level of the host material of the light emitting layer, a value calculated from the short wavelength end of the phosphorescence spectrum of the thin film of the host material can be used.

  The glass transition point of the host material in the light emitting layer is preferably 90 ° C. or higher and 400 ° C. or lower, more preferably 100 ° C. or higher and 380 ° C. or lower, and 120 ° C. or higher and 370 ° C. from the viewpoints of heat resistance and durability. More preferably, it is 140 ° C. or higher and 360 ° C. or lower.

In the light emitting layer of the present invention, if necessary, an electron transport material and a hole transport material can be used in addition to the compound.
As the electron transport material, a known electron transport material can be used, and examples thereof include those described later.
As the hole transport material, a known hole transport material can be used, and examples thereof include those described below.

  The glass transition point of the electron transport material and the hole transport material is preferably 90 ° C. or higher and 400 ° C. or lower, more preferably 100 ° C. or higher and 380 ° C. or lower, from the viewpoint of heat resistance and durability. It is more preferable that the temperature is not lower than 370 ° C and not higher than 370 ° C, and it is particularly preferable that the temperature is not lower than 140 ° C and not higher than 360 ° C.

The content of the phosphorescent light emitting material in the light emitting layer in the present invention is generally 0.1 to 100% by mass with respect to the total solid content mass of the light emitting layer, but in particular 0.5 to 30% by mass. It is preferable that it is 1-10 mass%, and it is especially preferable.
The content when the compound of the general formula (1) is used in the light emitting layer is the same as the phosphorescent light emitting material content in the light emitting layer, and the preferred range is also the same.

  As content of the host material in the light emitting layer in this invention, it is generally 1-99.9 mass% with respect to the total solid content mass of a light emitting layer, However, Among them, it is 50-99.5 mass%. It is preferably 70 to 99% by mass.

Although the film thickness of a light emitting layer is not specifically limited, Usually, the thing of the range of 1 nm-5 micrometers is preferable, More preferably, it is 5 nm-1 micrometer, More preferably, it is 10 nm-500 nm.
Although the formation method of a light emitting layer is not specifically limited, Like formation of the said organic compound layer, resistance heating vapor deposition, an electron beam, sputtering, a molecular lamination method, a coating method, an inkjet method, a printing method, LB method, A method such as a transfer method is used. Of these, resistance heating vapor deposition and coating are preferred.

The light emitting layer may be formed of a single compound or a plurality of compounds.
Further, the light emitting layer may be one or plural, and each layer may emit light with different emission colors, for example, white light may be emitted. White light may be emitted from a single light emitting layer.
When there are a plurality of light emitting layers, each light emitting layer may be formed of a single material or may be formed of a plurality of compounds.

  The light emitting layer of the organic electroluminescent element of the present invention may have at least one laminated structure. The number of stacked layers is preferably 2 or more and 50 or less, more preferably 4 or more and 30 or less, and still more preferably 6 or more and 20 or less.

  The thickness of each layer constituting the light emitting layer stack is not particularly limited, but is preferably 0.2 nm or more and 20 nm or less, more preferably 0.4 nm or more and 15 nm or less, and further preferably 0.5 nm or more and 10 nm or less, 1 nm to 5 nm is particularly preferable

The light emitting layer may have a plurality of domain structures. The light emitting layer may have another domain structure. For example, the light emitting layer, and a region of approximately 1 nm ³ of a mixture of a host material A and a fluorescent material B, may be configured in the region of about 1 nm ³ of a mixture of a host material C and a fluorescent material D. The diameter of each domain is preferably from 0.2 nm to 10 nm, more preferably from 0.3 nm to 5 nm, still more preferably from 0.5 nm to 3 nm, and particularly preferably from 0.7 nm to 2 nm.

The layer adjacent to the light-emitting layer (hole transport layer, electron transport layer, charge block layer, exciton block layer, etc.) has a T ₁ level (lowest triplet excited state energy level) of 60 Kcal / mol or more (251.4 KJ / mol or more), 90 Kcal / mol or less (377.1 KJ / mol or less) is preferable, 62 Kcal / mol or more (259.78 KJ / mol or more), 85 Kcal / mol or less (356.15 KJ / mol) Or less), more preferably 65 Kcal / mol or more (272.35 KJ / mol or more), 80 Kcal / mol or less (335.2 KJ / mol or less).
The T ₁ level is a value measured by the same method as described above.

  The compound represented by the general formula (1) may be a low molecular compound, and an oligomer compound or a polymer compound having a phosphorescent material in the main chain or side chain (weight average molecular weight (polystyrene conversion) is preferably 1000). ˜5000000, more preferably 2000 to 1000000, and still more preferably 3000 to 100,000. The compound of the present invention is preferably a low molecular compound.

(Base material)
The substrate used in the light-emitting device of the present invention is not particularly limited, but inorganic materials such as zirconia-stabilized yttrium and glass, polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyethylene, polycarbonate, and polyethersulfone. High molecular weight materials such as polyarylate, allyl diglycol carbonate, polyimide, polycycloolefin, norbornene resin, poly (chlorotrifluoroethylene), Teflon (registered trademark), polytetrafluoroethylene-polyethylene copolymer good.

(anode)
The anode supplies holes to a hole injection layer, a hole transport layer, a light emitting layer, and the like, and a metal, an alloy, a metal oxide, an electrically conductive compound, or a mixture thereof can be used. A material having a work function of 4 eV or more is preferable.
Specific examples of the anode material include conductive metal oxides such as tin oxide, zinc oxide, indium oxide, and indium tin oxide (ITO), metals such as gold, silver, chromium, and nickel, and conductivity with these metals. And mixtures of conductive metal oxides, inorganic conductive materials such as copper iodide and copper sulfide, organic conductive materials such as polyaniline, polythiophene, and polypyrrole, and laminates of these with ITO. Is a conductive metal oxide, and ITO is particularly preferable in terms of productivity, high conductivity, transparency, and the like.
The thickness of the anode can be appropriately selected depending on the material, but is usually preferably in the range of 10 nm to 5 μm, more preferably 50 nm to 1 μm, still more preferably 100 nm to 500 nm.

As the anode, a layer formed on a soda-lime glass, non-alkali glass, a transparent resin substrate or the like is usually used.
When glass is used, it is preferable to use non-alkali glass as the material in order to reduce ions eluted from the glass. Moreover, when using soda-lime glass, it is preferable to use what gave barrier coatings, such as a silica.
The thickness of the substrate is not particularly limited as long as it is sufficient to maintain the mechanical strength, but when glass is used, a thickness of 0.2 mm or more, preferably 0.7 mm or more is usually used.
Various methods are used for producing the anode depending on the material. For example, in the case of ITO, an electron beam method, a sputtering method, a resistance heating vapor deposition method, a chemical reaction method (sol-gel method, etc.), and a dispersion of indium tin oxide are applied. A film is formed by such a method.
The anode can be driven to lower the drive voltage of the element or increase the light emission efficiency by washing or other processing. For example, in the case of ITO, UV-ozone treatment, plasma treatment, etc. are effective.

(cathode)
The cathode supplies electrons to the electron injection layer, the electron transport layer, the light emitting layer, etc., and the adhesion, ionization potential, stability, etc., between the negative electrode and the adjacent layer such as the electron injection layer, electron transport layer, light emitting layer, etc. Selected in consideration of As a material for the cathode, a metal, an alloy, a metal halide, a metal oxide, an electrically conductive compound, or a mixture thereof can be used. Specific examples include an alkali metal (for example, Li, Na, K, etc.) and its fluoride. Or oxides, alkaline earth metals (eg Mg, Ca, etc.) and fluorides or oxides thereof, gold, silver, lead, aluminum, sodium-potassium alloys or their mixed metals, lithium-aluminum alloys or their mixtures Examples thereof include metals, magnesium-silver alloys or mixed metals thereof, rare earth metals such as indium and ytterbium, preferably materials having a work function of 4 eV or less, more preferably aluminum, lithium-aluminum alloys or mixed metals thereof. , Magnesium-silver alloys or mixed metals thereof. The cathode can take not only a single layer structure of the compound and the mixture but also a laminated structure including the compound and the mixture. For example, a laminated structure of aluminum / lithium fluoride and aluminum / lithium oxide is preferable. The film thickness of the cathode can be appropriately selected depending on the material, but is usually preferably in the range of 10 nm to 5 μm, more preferably 50 nm to 1 μm, still more preferably 100 nm to 1 μm.
For production of the cathode, methods such as an electron beam method, a sputtering method, a resistance heating vapor deposition method, a coating method, and a transfer method are used, and a metal can be vapor-deposited alone or two or more components can be vapor-deposited simultaneously. Furthermore, a plurality of metals can be vapor-deposited simultaneously to form an alloy electrode, or a previously prepared alloy may be vapor-deposited.
The sheet resistance of the anode and the cathode is preferably low, and is preferably several hundred Ω / □ or less.

(Hole injection layer, hole transport layer)
The material of the hole injection layer and the hole transport layer may be any one having a function of injecting holes from the anode, a function of transporting holes, or a function of blocking electrons injected from the cathode. Good.
Specific examples include carbazole, triazole, oxazole, oxadiazole, imidazole, polyarylalkane, pyrazoline, pyrazolone, phenylenediamine, arylamine, amino-substituted chalcone, styrylanthracene, fluorenone, hydrazone, stilbene, silazane, aromatic group Tertiary amine compounds, styrylamine compounds, aromatic dimethylidin compounds, porphyrin compounds, polysilane compounds, poly (N-vinylcarbazole), aniline copolymers, thiophene oligomers, conductive polymer oligomers such as polythiophene, organic Examples thereof include silane, carbon, the compound represented by the general formula (1) in the present invention, and derivatives thereof.
The film thicknesses of the hole injection layer and the hole transport layer are not particularly limited, but are usually preferably in the range of 1 nm to 5 μm, more preferably 5 nm to 1 μm, and still more preferably 10 nm to 500 nm. is there.
The hole injection layer and the hole transport layer may have a single-layer structure composed of one or more of the above-described materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions. .
As a method for forming the hole injection layer and the hole transport layer, a vacuum deposition method, an LB method, a method in which the hole injection transport material is dissolved or dispersed in a solvent, a coating method, an ink jet method, a printing method, or a transfer method is used. It is done.
In the case of the coating method, the material may be dissolved or dispersed together with the resin component for coating. Examples of the resin component include polyvinyl chloride, polycarbonate, polystyrene, polymethyl methacrylate, polybutyl methacrylate, polyester, polysulfone, polyphenylene oxide, polybutadiene, poly (N-vinylcarbazole), hydrocarbon resin, ketone resin, phenoxy resin, Examples thereof include polyamide, ethyl cellulose, vinyl acetate, ABS resin, polyurethane, melamine resin, unsaturated polyester resin, alkyd resin, epoxy resin, and silicon resin.

(Electron injection layer, electron transport layer)
The material for the electron injection layer and the electron transport layer may be any material having any one of a function of injecting electrons from the cathode, a function of transporting electrons, and a function of blocking holes injected from the anode. Specific examples include fragrances such as triazole, oxazole, oxadiazole, imidazole, fluorenone, anthraquinodimethane, anthrone, diphenylquinone, thiopyrandioxide, carbodiimide, fluorenylidenemethane, distyrylpyrazine, naphthalene, and perylene. Various metal complexes represented by cyclic tetracarboxylic acid anhydrides, metal complexes of phthalocyanine, 8-quinolinol, metal phthalocyanines, metal complexes having benzoxazole and benzothiazole as ligands, organic silanes, general formula (1 ) And derivatives thereof. Although the film thickness of an electron injection layer and an electron carrying layer is not specifically limited, The thing of the range of 1 nm-5 micrometers is preferable normally, More preferably, it is 5 nm-1 micrometer, More preferably, it is 10 nm-500 nm. The electron injection layer and the electron transport layer may have a single layer structure composed of one or more of the above-described materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions.
As a method for forming the electron injection layer and the electron transport layer, a vacuum vapor deposition method, an LB method, a method in which the electron injection transport material is dissolved or dispersed in a solvent, a coating method, an ink jet method, a printing method, a transfer method, and the like are used.
In the case of the coating method, the material may be dissolved or dispersed together with the resin component for coating. As this resin component, what was illustrated in the case of the positive hole injection transport layer is applicable, for example.

<Protective layer>
As a material for the protective layer, any material may be used as long as it has a function of suppressing the entry of elements that promote element deterioration such as moisture and oxygen into the element.
Specific examples thereof include metals such as In, Sn, Pb, Au, Cu, Ag, Al, Ti, and Ni, MgO, SiO, SiO ₂ , Al ₂ O ₃ , GeO, NiO, CaO, BaO, and Fe ₂ O. ₃ , metal oxides such as Y ₂ O ₃ and TiO ₂ , metal fluorides such as MgF ₂ , LiF, AlF ₃ , and CaF ₂ , SiN _x , SiO _x N _y Such as nitride, polyethylene, polypropylene, polymethyl methacrylate, polyimide, polyurea, polytetrafluoroethylene, polychlorotrifluoroethylene, polydichlorodifluoroethylene, copolymer of chlorotrifluoroethylene and dichlorodifluoroethylene, tetrafluoroethylene And a copolymer obtained by copolymerizing a monomer mixture containing at least one comonomer, a fluorine-containing copolymer having a cyclic structure in the copolymer main chain, a water-absorbing substance having a water absorption of 1% or more, a water absorption of 0 .1% or less of moisture-proof substances and the like.
The method for forming the protective layer is not particularly limited. For example, vacuum deposition, sputtering, reactive sputtering, MBE (molecular beam epitaxy), cluster ion beam, ion plating, plasma polymerization (high frequency excitation) (Ion plating method), plasma CVD method, laser CVD method, thermal CVD method, gas source CVD method, coating method, printing method, transfer method can be applied.

<Sealing>
Furthermore, the organic electroluminescent element of this invention may seal the whole element using a sealing container.
Further, a moisture absorbent or an inert liquid may be sealed in a space between the sealing container and the light emitting element. Although it does not specifically limit as a moisture absorber, For example, barium oxide, sodium oxide, potassium oxide, calcium oxide, sodium sulfate, calcium sulfate, magnesium sulfate, phosphorus pentoxide, calcium chloride, magnesium chloride, copper chloride Cesium fluoride, niobium fluoride, calcium bromide, vanadium bromide, molecular sieve, zeolite, magnesium oxide and the like. The inert liquid is not particularly limited, and examples thereof include fluorinated solvents such as paraffins, liquid paraffins, perfluoroalkanes, perfluoroamines, perfluoroethers, chlorinated solvents, and silicone oils. It is done.

Next, the light emitting device of the present invention will be described.
The light emitting device of the present invention is not particularly limited in terms of system, driving method, usage pattern, and the like.

The light-emitting element of the present invention obtains light emission by applying a direct current (which may include an alternating current component if necessary) voltage (usually 2 to 15 volts) or a direct current between the anode and the cathode. Can do.
The light-emitting element of the present invention may be a so-called top emission method (described in Japanese Patent Application Laid-Open Nos. 2003-208109, 2003-248441, 2003-257651, 2003-282261, etc.) in which light emission is extracted from the anode side.

  The light-emitting element of the present invention can improve the light extraction efficiency by various known devices. For example, by processing the substrate surface shape (for example, forming a fine concavo-convex pattern), controlling the refractive index of the substrate / ITO layer / organic layer, controlling the film thickness of the substrate / ITO layer / organic layer, etc. It is possible to improve light extraction efficiency and external quantum efficiency.

The external quantum efficiency of the light emitting device of the present invention is preferably 5% or more, more preferably 10% or more, and further preferably 13% or more.
As the value of the external quantum efficiency, the maximum value of the external quantum efficiency when the device is driven at 20 ° C. or the value of the external quantum efficiency near 100 to 300 cd / m ² when the device is driven at 20 ° C. is used. be able to. The value of the external quantum efficiency in the present invention is the maximum value of the external quantum efficiency when the device is driven at 20 ° C.
In the present invention, using a source measure unit type 2400 manufactured by Toyo Technica, a DC constant voltage is applied to the EL element to emit light, and the luminance is measured using a luminance meter BM-8 manufactured by Topcon Corporation, and is 200 cd / m ^2. A value obtained by calculating the external quantum efficiency at is used.
In the present invention, the external quantum efficiency of the device is calculated from the result and the relative luminous efficiency curve obtained by measuring the light emission luminance, the light emission spectrum, and the current density. That is, the number of input electrons can be calculated using the current density value. The emission luminance was converted to the number of photons emitted by integral calculation using the emission spectrum and the relative visibility curve (spectrum). From these, the external quantum efficiency (%) is calculated by “(number of photons emitted / number of electrons input to the device) × 100”.

  The emission spectrum can be measured using a multi-channel analyzer PMA-11 manufactured by Hamamatsu Photonics.

  The internal quantum efficiency of the light emitting device of the present invention is preferably 30% or more, more preferably 50% or more, and further preferably 70% or more. The internal quantum efficiency of the device is calculated by “internal quantum efficiency = external quantum efficiency / light extraction efficiency”. In a normal organic EL element, the light extraction efficiency is about 20%. However, the shape of the substrate, the shape of the electrode, the thickness of the organic layer, the thickness of the inorganic layer, the refractive index of the organic layer, the refractive index of the inorganic layer, etc. By devising it, it is possible to increase the light extraction efficiency to 20% or more.

  The light-emitting element of the present invention may contain a blue fluorescent light-emitting compound, or a multi-color using a blue light-emitting element containing the blue fluorescent compound and a light-emitting element of the present invention other than the blue light-emitting element at the same time. A light emitting device or a full color light emitting device may be manufactured.

When the light-emitting element of the present invention is a blue light-emitting element, the maximum wavelength of light emission is preferably 390 nm or more and 495 nm or less, more preferably 400 nm or more and 490 nm or less from the viewpoint of blue color purity. The spectrum waveform was measured using a multi-channel analyzer PMA-11 manufactured by Hamamatsu Photonics.
The light emitting device of the present invention may have a light emission maximum wavelength of 500 nm or more, or may be a white light emitting device.

When the light-emitting device of the present invention is a blue light-emitting device, from the viewpoint of blue color purity, the x value of the CIE chromaticity value of light emission is preferably 0.22 or less, more preferably 0.20 or less.
In addition, when the light emitting device of the present invention is a blue light emitting device, from the viewpoint of blue color purity, the y value of the CIE chromaticity value of light emission is preferably 0.25 or less, more preferably 0.20 or less. More preferably 0.15 or less.
CIE chromaticity values were measured using PMA-11 manufactured by Hamamatsu Photonics.

  In the light emitting device of the present invention, from the viewpoint of color purity, the half width of the emission spectrum is preferably 100 nm or less, more preferably 90 nm or less, further preferably 80 nm or less, and particularly preferably 70 nm or less. The half-value width of the emission spectrum is a value obtained by measuring a spectrum waveform using a multi-channel analyzer PMA-11 manufactured by Hamamatsu Photonics.

  The use of the light emitting device of the present invention is not particularly limited, but is suitable for the fields of display device, display, backlight, electrophotography, illumination light source, recording light source, exposure light source, reading light source, sign, signboard, interior, optical communication, etc. Can be used for

  Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

[Comparative Example 1]
(Elements described in International Publication No. 04/016711 pamphlet)
The cleaned ITO substrate was put into a vapor deposition apparatus, and copper phthalocyanine 10 nm was vapor-deposited, and NPD (N, N′-di-α-naphthyl-N, N′-diphenyl) -benzidine) was vapor-deposited thereon 30 nm. On top of this, the following compound A and the following compound B were co-deposited at a ratio of 6:94 (mass ratio) of 30 nm, and the following BAlq ₂ was deposited thereon at 30 nm. On this, 1 nm of lithium fluoride was vapor-deposited, and 100 nm of aluminum was vapor-deposited on this, and the EL element was produced.

As a result of emitting light by applying a constant DC voltage to the EL element using a source measure unit 2400 type manufactured by Toyo Technica, blue-green light emission was obtained. The luminance was measured using Topcon BM-8.
Further, the spectrum waveform was measured using a multi-channel analyzer PMA-11 manufactured by Hamamatsu Photonics. From these measurement results, values of driving voltage, external quantum efficiency, and emission wavelength peak at 200 cd / m ² were obtained.
Further, a constant current driving at an initial luminance 200 cd / m ^2, the luminance is measured luminance half-life T (1/2) required to reach a 100 cd / m ^2, and the durability index.

[Example 1]
In Comparative Example 1, an element was produced and evaluated in the same manner as Comparative Example 1 except that the exemplified compound (1-1) in the present invention was used instead of the compound A of the light emitting element.
As a result of applying a DC constant voltage to the EL element to emit light, blue light emission with high color purity was obtained with respect to the element of Comparative Example 1. The driving durability of the light emitting element was three times that of the element of Comparative Example 1.

[Example 2]
In Comparative Example 1, an element was produced and evaluated in the same manner as Comparative Example 1 except that the exemplified compound (1-2) in the present invention was used instead of the compound A of the light emitting element.
As a result of applying a direct current constant voltage to the obtained EL element to emit light, blue light emission with high color purity was obtained with respect to the element of Comparative Example 1. The driving durability of the element was twice that of the element of Comparative Example 1.

  Similar effects can be obtained also in devices using other exemplary compounds in the present invention.

Claims (4)

An organic electroluminescence device having at least one organic compound layer including a light emitting layer between a pair of electrodes, wherein the organic compound layer contains a compound represented by the following general formula (1) Electroluminescent device.

[R ¹¹ represents a hydrogen atom or a substituent. R ¹² and R ¹⁴ each independently represents a hydrogen atom or a substituent, and at least one of R ¹² and R ¹⁴ is an electron-withdrawing group. R ¹³ represents an alkyl group or an aromatic group substituted with at least one fluorine atom. Q ¹¹ represents a group that forms a nitrogen-containing heterocycle, L ¹¹ represents a ligand, and M ¹¹ represents an iridium ion, a rhenium ion, a palladium ion, or a rhodium ion. Z ¹¹ represents a carbon atom or a nitrogen atom. When Z ¹¹ is a carbon atom, the bond between Z ¹¹ and the nitrogen atom is a double bond, and when Z ¹¹ is a nitrogen atom, the bond between Z ¹¹ and the nitrogen atom is a single bond. m ¹¹ represents an integer of 1 to 3, m ¹² represents an integer of 0-4. ] The organic electroluminescent element according to claim 1, wherein the compound represented by the general formula (1) is a compound represented by the following general formula (2).

[R ²¹ denotes a hydrogen atom or a substituent. R ²² and R ²⁴ each independently represent a hydrogen atom or a substituent, and at least one of R ²² and R ²⁴ is an electron-withdrawing group. R ²³ represents an alkyl group or an aromatic group substituted with at least one fluorine atom. Q ²¹ represents a group that forms a nitrogen-containing heterocycle, L ²¹ represents a ligand, and M ²¹ represents an iridium ion, a rhenium ion, a palladium ion, or a rhodium ion. m ²¹ represents an integer of 1 to 3, and m ²² represents an integer of 0 to 4. ] The organic electroluminescent element according to claim 1 or 2, wherein the compound represented by the general formula (1) is a compound represented by the following general formula (3).

[R ³¹ represents a hydrogen atom or a substituent. Q ³¹ represents a group that forms a nitrogen-containing heterocycle, L ³¹ represents a ligand, and M ³¹ represents an iridium ion, a rhenium ion, a palladium ion, or a rhodium ion. R ³⁵ represents a substituent. m ³¹ represents an integer of 1 to 3, and m ³² represents an integer of 0 to 4. n ³¹ denotes an integer 1 to 5, n ³² represents an integer of 0-4. n ³¹ + n ³² ≦ 5. ] The organic electroluminescent device according to any one of claims 1 to 3, wherein the compound represented by the general formula (1) is a compound represented by the following general formula (4).

[R ⁴¹ represents a hydrogen atom or a substituent. Q ⁴¹ represents a group that forms a nitrogen-containing heterocycle, L ⁴¹ represents a ligand, and M ⁴¹ represents an iridium ion, a rhenium ion, a palladium ion, or a rhodium ion. m ⁴¹ represents an integer of 1 to 3, m ⁴² represents an integer of 0-4. ]