JP4796802B2 - Organic electroluminescence device - Google Patents

Description

  The present invention relates to an organic electroluminescence device that emits light by converting electric energy into light.

  Organic electroluminescence devices have been actively researched and developed because they can emit light with high brightness when driven at a low voltage. An organic electroluminescent element has an organic layer between a pair of electrodes, and electrons injected from the cathode and holes injected from the anode recombine in the organic layer, and the generated exciton energy is used for light emission. To do.

An organic electroluminescent element containing a nonionic gold complex is disclosed as a material for an organic electroluminescent element (for example, see Patent Document 1). However, a gold complex that is excellent in at least one of further luminous efficiency and durability is desired.
JP 2004-158297 A

  An object of the present invention is to provide an organic electroluminescent device excellent in at least one of luminous efficiency and durability. Another object of the present invention is to provide a complex compound (material for an organic electroluminescent element) suitable for an organic electroluminescent element.

（一般式（Ｉ）中、Ｘ ¹¹ 、Ｘ ¹² 、及びＸ ¹³ はフェニル基を表す。Ｙ ¹¹ はピリジル基を表す。Ｌ ¹ 、Ｌ ² 及びＬ ⁴ は単結合を表し、Ｌ ³ はジメチルメチレン基又はジフェニルメチレン基を表す。ｎ ¹ は０を表し、ｎ ² 、ｎ ³ 、及びｎ ⁴ は１を表す。ここで、ｎ ¹ が０であるとは、Ｘ ¹¹ とＸ ¹² の間が連結されていないことを表す。）
本発明者らは、上記課題を解決すべく検討した結果、特定の構造を有する四座配位子の三価の金錯体を有機層に含有する有機ＥＬ素子が、上記課題を解決することを見出した。すなわち、本発明は下記の手段により達成された。
〔１〕一対の電極間に少なくとも一層の有機層を有する有機電界発光素子であって、下記一般式（Ｉ）で表される化合物の少なくとも一種を有機層に含有することを特徴とする有機電界発光素子。 The present invention relates to the following item <1>, but other matters are also described for reference.
<1>
An organic electroluminescent device having at least one organic layer between a pair of electrodes, wherein the organic layer contains at least one compound represented by the following general formula (I).

(In the general formula (I), X ¹¹ , X ¹² and X ¹³ represent a phenyl group. Y ¹¹ represents a pyridyl group. L ¹ , L ² and L ⁴ represent a single bond, and L ³ represents dimethylmethylene. Represents a group or a diphenylmethylene group, n ¹ represents 0, and n ² , n ³ , and n ⁴ represent 1. Here, n ¹ is 0 when X ¹¹ and X ¹² are connected. It means not being done.)
As a result of investigations to solve the above problems, the present inventors have found that an organic EL element containing a trivalent gold complex of a tetradentate ligand having a specific structure in an organic layer solves the above problems. It was. That is, the present invention has been achieved by the following means.
[1] An organic electroluminescence device having at least one organic layer between a pair of electrodes, wherein the organic layer contains at least one compound represented by the following general formula (I): Light emitting element.

(In the general formula (I), X ¹¹ , X ¹² and X ¹³ each independently represent an anionic coordination site. Y ¹¹ represents a neutral coordination site. L ¹ , L ² , L ³ and L ⁴ each independently represents a single bond or a linking group, n ¹ , n ² , n ³ and n ⁴ each independently represents 1 or 0, and n ¹ + n ³ ≠ 0 And n ² + n ⁴ ≠ 0 at the same time, where n ¹ , n ² , n ³ , and n ⁴ are 0 means that X ¹¹ and X ¹² , X ¹² and X ¹³ , X ¹³ and Y ¹¹ and Y ¹¹ and X ¹¹ are not linked.)

[2] The organic electroluminescent element as described in [1] above, wherein the compound represented by the general formula (I) is a compound represented by the following general formula (II).

(In the general formula (II), X ¹¹ , X ¹² and X ¹³ each independently represents an anionic coordination site. L ¹ , L ² , L ³ and L ⁴ are each independently .n ¹ represents a single bond or a linking group, n ^2, n ^3, and n ⁴ each independently represent 1 or 0, satisfy n ¹ + n ³ ≠ 0 and n ² + n ⁴ ≠ 0 at the same time. here N ¹ , n ² , n ³ , and n ⁴ are 0, X ¹¹ and X ¹² , X ¹² and X ¹³ , X ¹³ and pyridine corresponding to Y ¹¹ in the general formula (I), respectively. This represents that the ring and the pyridine ring and X ¹¹ are not linked. R ²¹ , R ²² and R ²³ each independently represents a hydrogen atom or a substituent.)

  By containing the complex represented by the general formulas (I) and (II) of the present invention (used herein in the same meaning as the “complex of the present invention”) in the organic layer, high luminous efficiency (for example, external quantum) It is possible to provide an organic electroluminescent element (used synonymously with “the element of the present invention” in the present specification) which is excellent in at least one of efficiency and high durability.

  In this specification, the substituent group A is defined as follows.

(Substituent group A)
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, For example, vinyl, allyl, 2-butenyl, 3-pentenyl, etc.), alkynyl group (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms, For example, propargyl, 3-pentynyl, etc.), aryl groups (preferably having 6 to 30 carbon atoms, more preferably Prime 6-20, particularly preferably 6 to 12 carbon atoms, such as phenyl, p- methylphenyl, naphthyl, anthranyl.),
An amino group (preferably having 0 to 30 carbon atoms, more preferably 0 to 20 carbon atoms, particularly preferably 0 to 10 carbon atoms, such as amino, methylamino, dimethylamino, diethylamino, dibenzylamino, diphenylamino, ditolylamino; And alkoxy groups (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 10 carbon atoms, such as methoxy, ethoxy, butoxy, 2-ethylhexyloxy) An aryloxy group (preferably having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, and particularly preferably 6 to 12 carbon atoms, such as phenyloxy, 1-naphthyloxy, 2- Naphthyloxy, etc.), heterocyclic oxy groups (preferably having 1 to 30 carbon atoms, more preferred) Has 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include pyridyloxy, pyrazyloxy, pyrimidyloxy, quinolyloxy, and the like, and acyl groups (preferably having 1 to 30 carbon atoms, more preferably carbon numbers). 1 to 20, particularly preferably 1 to 12 carbon atoms, such as acetyl, benzoyl, formyl, pivaloyl, etc.), alkoxycarbonyl groups (preferably 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms). , Particularly preferably having 2 to 12 carbon atoms, such as methoxycarbonyl, ethoxycarbonyl, etc.), an aryloxycarbonyl group (preferably having 7 to 30 carbon atoms, more preferably having 7 to 20 carbon atoms, particularly preferably). It has 7 to 12 carbon atoms, such as 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 Has 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms, and examples thereof include acetylamino, benzoylamino, and the like, and an alkoxycarbonylamino group (preferably having 2 carbon atoms). To 30, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonylamino, and the like, an aryloxycarbonylamino group (preferably 7 to 30 carbon atoms, more preferably Has 7 to 20 carbon atoms, particularly preferably 7 to 12 carbon atoms, such as phenyloxycarbonyl And ruamino. ), A sulfonylamino group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methanesulfonylamino and benzenesulfonylamino), 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, phenylsulfamoyl, 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, and examples thereof include carbamoyl, methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl and the like. ), An alkylthio group (preferably having 1 to 30 carbon atoms). More preferably, it is C1-C20, Most preferably, it is C1-C12, for example, methylthio, ethylthio etc. are mentioned, for example, An arylthio group (Preferably C6-C30, More preferably C6-C20 In particular, it has 6 to 12 carbon atoms, and examples thereof include phenylthio.), A heterocyclic thio group (preferably 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to carbon atoms). 12 and examples thereof include pyridylthio, 2-benzimidazolylthio, 2-benzoxazolylthio, 2-benzthiazolylthio, and the like, and sulfonyl groups (preferably having 1 to 30 carbon atoms, more preferably carbon numbers). 1 to 20, particularly preferably 1 to 12 carbon atoms, such as mesyl, tosyl, etc.), sulfinyl group (preferably C1-C30, More preferably, it is C1-C20, Most preferably, it is C1-C12, for example, methanesulfinyl, benzenesulfinyl etc. are mentioned), a ureido group (preferably C1-C30, More preferably, it is C1-C20, Most preferably, it is C1-C12, for example, ureido, methylureido, phenylureido etc. are mentioned), phosphoric acid amide groups (preferably C1-C30, more preferably). Has 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as diethyl phosphoric acid amide and phenyl phosphoric acid amide), hydroxy group, mercapto group, halogen atom (for example, fluorine atom, chlorine atom) Bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfur An inino group, a hydrazino group, an imino group, a heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and examples of the hetero atom include a nitrogen atom, an oxygen atom, and a sulfur atom, Specific examples include imidazolyl, pyridyl, quinolyl, furyl, thienyl, piperidyl, morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, carbazolyl group, azepinyl group and the like. ), A silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, particularly preferably 3 to 24 carbon atoms, such as trimethylsilyl, triphenylsilyl, etc.), a silyloxy group (preferably Is a carbon number of 3 to 40, more preferably a carbon number of 3 to 30, and particularly preferably a carbon number of 3 to 24. Examples thereof include trimethylsilyloxy and triphenylsilyloxy.

  The device of the present invention will be described in detail. The element of the present invention has at least one organic layer between a pair of electrodes. The element of the present invention has a pair of electrodes (a cathode and an anode) on a substrate, and an organic layer between both electrodes. In view of the properties of the element, at least one of the anode and the cathode is preferably transparent.

  The element of the present invention is characterized by containing a trivalent gold complex of a tetradentate ligand having a specific structure in the organic layer. The function of the at least one organic layer is not particularly limited, but in addition to the light-emitting layer, a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, a hole block layer, an electron block layer, and an exciton block It may be a layer, a protective layer, or the like. In the element of the present invention, in addition to the at least one organic layer, a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, a hole block layer, an electron block layer, an exciton block layer, a protection You may have a layer. Each of these layers may have other functions.

  As an aspect of lamination of the organic layer in the present invention, an aspect in which a hole transport layer, a light emitting layer, and an electron transport layer are laminated in this order from the anode side is preferable. Further, a charge blocking layer or the like may be provided between the hole transport layer and the light-emitting layer, or between the light-emitting layer and the electron transport layer. A hole injection layer may be provided between the anode and the hole transport layer, and an electron injection layer may be provided between the cathode and the electron transport layer. Each layer may be divided into a plurality of secondary layers.

  The complex of the present invention can be contained in any layer when the organic layer is composed of a plurality of layers. The complex of the present invention is preferably contained in the light emitting layer, more preferably contained in the light emitting layer as a light emitting material, and particularly preferably contained in the light emitting layer together with at least one kind of host material.

  The content of the complex of the present invention, when contained in the light emitting layer as a light emitting material, is preferably in the range of 0.1% by mass or more and 50% by mass or less, and 0.2% by mass or more with respect to the total mass of the layer. A range of 30% by mass or less is more preferable, a range of 0.3% by mass or more and 20% by mass or less is further preferable, and a range of 0.5% by mass or more and 15% by mass or less is most preferable.

  The host material is a compound mainly responsible for charge injection and transport in the light emitting layer, and itself is a compound that does not substantially emit light. In this specification, “substantially no light emission” means that the light emission amount from the substantially non-light emitting compound is preferably 5% or less, more preferably 3% or less of the total light emission amount of the entire device. More preferably, it means 1% or less.

  The concentration of the host material in the light emitting layer is not particularly limited, but is preferably the main component (the component having the largest content) in the light emitting layer, more preferably 50% by mass or more and 99.9% by mass or less, 70 mass% or more and 99.8 mass% or less are more preferable, 80 mass% or more and 99.7 mass% or less are especially preferable, and 90 mass% or more and 99.5 mass% or less are the most preferable.

  The glass transition point of the host material is preferably 100 ° C. or higher and 500 ° C. or lower, more preferably 110 ° C. or higher and 300 ° C. or lower, and further preferably 120 ° C. or higher and 250 ° C. or lower.

  The fluorescence wavelength in the film state of the host material contained in the light emitting layer of the present invention is preferably in the range of 400 nm to 650 nm, more preferably in the range of 420 nm to 600 nm, and in the range of 440 nm to 550 nm. More preferably.

  As the host material used in the present invention, the compounds described in paragraphs 0113 to 0161 of JP-A No. 2002-1000047 and the compounds described in paragraphs 0087 to 0098 of JP-A No. 2004-214179 can be suitably used. However, it is not limited to these.

The complex represented by the general formula (I) will be described. In the general formula (I), X ¹¹ , X ¹² and X ¹³ each independently represent a group that binds to a gold ion as an anionic coordination site. X ¹¹ , X ¹² and X ¹³ are each independently bonded to a gold ion by a carbon atom, a nitrogen atom, a silicon atom, a phosphorus atom, or an oxygen atom. A group bonded by a sulfur atom is preferable, a group bonded by a carbon atom, a nitrogen atom, an oxygen atom or a sulfur atom is more preferable, a group bonded by a carbon atom, a nitrogen atom or an oxygen atom is more preferable, and a carbon atom or nitrogen is more preferable. A group bonded by an atom is more preferable, and a group bonded by a carbon atom is particularly preferable.

X ¹¹ , X ¹² , and X ¹³ bonded to a gold ion by a carbon atom are preferably an aryl group or a heteroaryl group. Specifically, a phenyl group, a pyridyl group, a pyrimidinyl group, a pyrazinyl group, a thienyl group, or a furyl group Pyrrolyl group, imidazolyl group, pyrazolyl group, oxazolyl group, thiazolyl group, triazolyl group, oxadiazolyl group, thiadiazolyl group and the like. These groups may have a substituent, if possible, or may be condensed with another ring. As the substituent, those exemplified as the substituent group A can be applied. Examples of the condensed ring include a benzene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a thiophene ring, a furan ring, a pyrrole ring, an imidazole ring, a pyrazole ring, an oxazole ring, and a thiazole ring.
X ¹¹ , X ¹² , and X ¹³ bonded to a gold ion with a nitrogen atom are preferably nitrogen-containing heteroaryl groups and amino groups. Specifically, pyrrolyl group, imidazolyl group, pyrazolyl group, triazolyl group, alkylamino group , Arylamino group, heteroarylamino group and the like. These groups may have a substituent, if possible, or other rings may be condensed. As the substituent, those exemplified as the substituent group A can be applied. Examples of the condensed ring include a benzene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a thiophene ring, a furan ring, a pyrrole ring, an imidazole ring, a pyrazole ring, an oxazole ring, and a thiazole ring.

As X ¹¹ , X ¹² , and X ¹³ bonded to the gold ion with an oxygen atom, an alkoxy group, an aryloxy group, a heteroaryloxy group, a carboxyl group, and a silyloxy group are preferable. These groups may have a substituent if possible. As the substituent, those exemplified as the substituent group A can be applied.
X ¹¹ , X ¹² , and X ¹³ bonded to a gold ion with a sulfur atom are preferably an alkylthio group, an arylthio group, a heteroarylthio group, or a thiocarboxyl group. These groups may have a substituent if possible. As the substituent, those exemplified as the substituent group A can be applied.
Examples of X ¹¹ , X ¹² and X ¹³ bonded to the gold ion with a silicon atom include a substituted or unsubstituted silyl group. As the substituent, those exemplified as the substituent group A can be applied.
Examples of X ¹¹ , X ¹² and X ¹³ bonded to the gold ion with a phosphorus atom include a substituted or unsubstituted phosphino group. As the substituent, those exemplified as the substituent group A can be applied.

Of X ¹¹ , X ¹² and X ¹³ , at least one is preferably a group bonded by a carbon atom, and more preferably a phenyl group.

In general formula (I), Y ¹¹ represents a neutral coordination site. Y ¹¹ is preferably a group coordinated to a gold ion by a nitrogen atom, a group coordinated by an oxygen atom, a group coordinated by a sulfur atom, or a group coordinated by a phosphorus atom, and coordinated by a nitrogen atom or an oxygen atom. Is more preferably a group that coordinates with a nitrogen atom.

Y ¹¹ coordinated to a gold ion by a nitrogen atom is preferably a nitrogen-containing heteroaryl group, a substituted or unsubstituted amino group, specifically a pyridyl group, a pyrimidyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, Examples include a pyrazolyl group, an imidazolyl group, a triazolyl group, an oxazolyl group, a thiazolyl group, and a phenylamino group. These groups may have a substituent, if possible, or other rings may be condensed. As the substituent, those exemplified as the substituent group A can be applied. Examples of the condensed ring include a benzene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a thiophene ring, a furan ring, a pyrrole ring, an imidazole ring, a pyrazole ring, an oxazole ring, and a thiazole ring.

Y ¹¹ that coordinates to the gold ion with an oxygen atom is preferably an oxygen-containing heteroaryl group or an ether group, and examples thereof include an oxazolyl group, a dialkyl ether, and a diaryl ether. These groups may have a substituent, if possible, or other rings may be condensed. As the substituent, those exemplified as the substituent group A can be applied. Examples of the condensed ring include a benzene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a thiophene ring, a furan ring, a pyrrole ring, an imidazole ring, a pyrazole ring, an oxazole ring, and a thiazole ring.

Y ¹¹ that coordinates to a gold ion with a sulfur atom is preferably a sulfur-containing heteroaryl group or a thioether group, and examples thereof include a thiazolyl group, a dialkylthioether, and a diarylthioether. These groups may have a substituent, if possible, or other rings may be condensed. As the substituent, those exemplified as the substituent group A can be applied. Examples of the condensed ring include a benzene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a thiophene ring, a furan ring, a pyrrole ring, an imidazole ring, a pyrazole ring, an oxazole ring, and a thiazole ring.
Y ¹¹ coordinated to a gold ion by a phosphorus atom is preferably a substituted or unsubstituted phosphine or phosphine oxide. As the substituent, those exemplified as the substituent group A can be applied.

Y ¹¹ is preferably a substituted or unsubstituted pyridyl group or pyrazinyl group, and more preferably a substituted or unsubstituted pyridyl group.

L ¹ , L ² , L ³ and L ⁴ each independently represents a single bond or a divalent linking group. Although it does not specifically limit as a bivalent coupling group, The coupling group which contains a carbon atom, a nitrogen atom, an oxygen atom, a sulfur atom, or a silicon atom is preferable. Specific examples of the divalent linking group are shown below, but the present invention is not limited thereto.

  These linking groups may further have a substituent if possible, and the substituents that can be introduced include those listed as the substituent group A.

L ¹ is preferably a dialkylmethylene group, a diarylmethylene group or a diheteroarylmethylene group, more preferably a dimethylmethylene group or a diphenylmethylene group, and still more preferably a dimethylmethylene group.

n ¹ , n ² , n ³ , and n ⁴ each independently represent 1 or 0, and satisfy n ¹ + n ³ ≠ 0 and n ² + n ⁴ ≠ 0 at the same time. Here, n ¹ , n ² , n ³ , and n ⁴ are 0 when X ¹¹ and X ¹² , X ¹² and X ¹³ , X ¹³ and Y ¹¹ , and Y ¹¹ and X ¹¹ are connected. It means not being done. By simultaneously satisfying n ¹ + n ³ ≠ 0 and n ² + n ⁴ ≠ 0, the compound represented by the general formula (I) represents a gold complex having a tetradentate ligand.

Of the complexes represented by the general formula (I), a complex represented by the general formula (II) is more preferable. In the general formula (II), X ¹¹ , X ¹² , X ¹³ , L ¹ , L ² , L ³ , L ⁴ , n ¹ , n ² , n ³ , n ⁴ are the same as those in the general formula (I). The preferred range is also the same. R ²¹ , R ²² and R ²³ represent a hydrogen atom or a substituent. As the substituents represented by R ²¹ , R ²² and R ²³ , those exemplified as the substituent group A can be applied. R ²¹ , R ²² and R ²³ may be bonded to each other to form a ring, if possible.
R ²¹ and R ²³ are preferably a hydrogen atom, alkyl group, aryl group, amino group, alkoxy group, aryloxy group, acyl group, alkoxycarbonyl group, alkylthio group, sulfonyl group, hydroxy group, halogen atom, cyano group. , A nitro group, a heterocyclic group, more preferably a hydrogen atom, an alkyl group, an aryl group, a halogen atom, a cyano group, or a heterocyclic group, still more preferably a hydrogen atom, a methyl group, a t-butyl group, A trifluoromethyl group, a phenyl group, a fluorine atom, a cyano group, and a pyridyl group are more preferable, and a hydrogen atom, a methyl group, and a fluorine atom are more preferable.
R ²² is preferably a hydrogen atom, alkyl group, aryl group, amino group, alkoxy group, aryloxy group, alkylthio group, arylthio group, halogen atom, cyano group, or heterocyclic group, more preferably a hydrogen atom. , An alkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, and a heterocyclic group, more preferably a hydrogen atom, an alkyl group, an amino group, an alkoxy group, and a heterocyclic group, and more preferably a hydrogen atom. An atom, a methyl group, a t-butyl group, a dimethylamino group, a diphenylamino group, a methoxy group, and a carbazolyl group, particularly preferably a hydrogen atom.

Specific examples of the complex represented by the general formula (I) in the present invention are illustrated below, but the present invention is not limited thereto (Ph represents a phenyl group, and ^t Bu represents a tertiary group. Represents a butyl group).

  Each element constituting the element of the present invention will be described in detail.

<Board>
The substrate used in the present invention is preferably a substrate that does not scatter or attenuate light emitted from the organic layer. Specific examples include zirconia-stabilized yttrium (YSZ), inorganic materials such as glass, polyesters such as polyethylene terephthalate, polybutylene phthalate, and polyethylene naphthalate, polystyrene, polycarbonate, polyethersulfone, polyarylate, polyimide, and polycycloolefin. , Organic materials such as norbornene resin and poly (chlorotrifluoroethylene).
For example, when glass is used as the substrate, alkali-free glass is preferably used 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. In the case of an organic material, it is preferable that it is excellent in heat resistance, dimensional stability, solvent resistance, electrical insulation, and workability.

  There is no restriction | limiting in particular about the shape of a board | substrate, a structure, a magnitude | size, It can select suitably according to the use, purpose, etc. of a light emitting element. In general, the shape of the substrate is preferably a plate shape. The structure of the substrate may be a single layer structure, a laminated structure, may be formed of a single member, or may be formed of two or more members.

  The substrate may be colorless and transparent or colored and transparent, but is preferably colorless and transparent in that it does not scatter or attenuate light emitted from the organic light emitting layer.

The substrate can be provided with a moisture permeation preventing layer (gas barrier layer) on the front surface or the back surface.
As a material for the moisture permeation preventive layer (gas barrier layer), inorganic materials such as silicon nitride and silicon oxide are preferably used. The moisture permeation preventing layer (gas barrier layer) can be formed by, for example, a high frequency sputtering method. When a thermoplastic substrate is used, a hard coat layer, an undercoat layer, or the like may be further provided as necessary.

<Anode>
The anode usually only needs to have a function as an electrode for supplying holes to the organic layer, and there is no particular limitation on the shape, structure, size, etc., depending on the use and purpose of the light-emitting element, It can select suitably from well-known electrode materials. As described above, the anode is usually provided as a transparent anode.

  Suitable examples of the material for the anode include metals, alloys, metal oxides, conductive compounds, and mixtures thereof. Specific examples of the anode material include conductive metals such as tin oxide doped with antimony and fluorine (ATO, FTO), tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO). Metals such as oxides, gold, silver, chromium, nickel, and mixtures or laminates of these metals and conductive metal oxides, inorganic conductive materials such as copper iodide and copper sulfide, polyaniline, polythiophene, polypyrrole, etc. Organic conductive materials, and a laminate of these and ITO. Among these, conductive metal oxides are preferable, and ITO is particularly preferable from the viewpoints of productivity, high conductivity, transparency, and the like.

  The anode is composed of, for example, a wet method such as a printing method and a coating method, a physical method such as a vacuum deposition method, a sputtering method, and an ion plating method, and a chemical method such as a CVD and a plasma CVD method. It can be formed on the substrate according to a method appropriately selected in consideration of suitability with the material to be processed. For example, when ITO is selected as the anode material, the anode can be formed according to a direct current or high frequency sputtering method, a vacuum deposition method, an ion plating method, or the like.

  In the organic electroluminescent element of the present invention, the formation position of the anode is not particularly limited and can be appropriately selected according to the use and purpose of the light emitting element, but it is preferably formed on the substrate. In this case, the anode may be formed on the entire one surface of the substrate, or may be formed on a part thereof.

The patterning for forming the anode may be performed by chemical etching such as photolithography, or may be performed by physical etching such as laser, or vacuum deposition or sputtering with a mask overlapped. It may be performed by a lift-off method or a printing method.

  The thickness of the anode can be appropriately selected depending on the material constituting the anode and cannot be generally defined, but is usually about 10 nm to 50 μm, and preferably 50 nm to 20 μm.

The resistance value of the anode is preferably 10 ³ Ω / □ or less, and more preferably 10 ² Ω / □ or less. When the anode is transparent, it may be colorless and transparent or colored and transparent. In order to take out light emission from the transparent anode side, the transmittance is preferably 60% or more, and more preferably 70% or more.

  The transparent anode is described in detail in the book “New Development of Transparent Electrode Films” published by CMC (1999), supervised by Yutaka Sawada, and the matters described here can be applied to the present invention. In the case of using a plastic substrate having low heat resistance, a transparent anode formed using ITO or IZO at a low temperature of 150 ° C. or lower is preferable.

<Cathode>
The cathode usually has a function as an electrode for injecting electrons into the organic layer, and there is no particular limitation on the shape, structure, size, etc., and it is known depending on the use and purpose of the light-emitting element. The electrode material can be selected as appropriate.

  Examples of the material constituting the cathode include metals, alloys, metal oxides, electrically conductive compounds, and mixtures thereof. Specific examples include alkali metals (eg, Li, Na, K, Cs, etc.), alkaline earth metals (eg, Mg, Ca, etc.), gold, silver, lead, aluminum, sodium-potassium alloys, lithium-aluminum alloys, magnesium. -Rare earth metals such as silver alloys, indium, ytterbium, and the like. These may be used alone, but two or more can be suitably used in combination from the viewpoint of achieving both stability and electron injection.

Among these, as a material constituting the cathode, an alkali metal or an alkaline earth metal is preferable from the viewpoint of electron injecting property, and a material mainly composed of aluminum is preferable from the viewpoint of excellent storage stability.
The material mainly composed of aluminum is aluminum alone, an alloy of aluminum and 0.01 to 10% by mass of alkali metal or alkaline earth metal, or a mixture thereof (for example, lithium-aluminum alloy, magnesium-aluminum alloy, etc.) Say.

  The cathode materials are described in detail in JP-A-2-15595 and JP-A-5-121172, and the materials described in these publications can also be applied in the present invention.

  There is no restriction | limiting in particular about the formation method of a cathode, According to a well-known method, it can carry out. For example, the cathode described above is configured from a wet method such as a printing method or a coating method, a physical method such as a vacuum deposition method, a sputtering method, or an ion plating method, or a chemical method such as CVD or plasma CVD method. It can be formed according to a method appropriately selected in consideration of suitability with the material. For example, when a metal or the like is selected as the cathode material, one or more of them can be simultaneously or sequentially performed according to a sputtering method or the like.

Patterning when forming the cathode may be performed by chemical etching such as photolithography, physical etching by laser, or the like, or by vacuum deposition or sputtering with the mask overlaid. It may be performed by a lift-off method or a printing method.

In the present invention, the cathode forming position is not particularly limited, and may be formed on the entire organic layer or a part thereof.
Further, a dielectric layer made of an alkali metal or alkaline earth metal fluoride or oxide may be inserted between the cathode and the organic layer with a thickness of 0.1 to 5 nm. This dielectric layer can also be regarded as a kind of electron injection layer. The dielectric layer can be formed by, for example, a vacuum deposition method, a sputtering method, an ion plating method, or the like.

The thickness of the cathode can be appropriately selected depending on the material constituting the cathode and cannot be generally defined, but is usually about 10 nm to 5 μm, and preferably 50 nm to 1 μm.
Further, the cathode may be transparent or opaque. The transparent cathode can be formed by depositing a thin cathode material to a thickness of 1 to 10 nm and further laminating a transparent conductive material such as ITO or IZO.

<Organic layer>
The organic layer in the present invention will be described. The element of the present invention has at least one organic layer including a light emitting layer, and the organic layer other than the organic light emitting layer includes a hole transport layer, an electron transport layer, and a hole block layer as described above. , Electron blocking layer, hole injection layer, electron injection layer and the like.

-Formation of organic layer-
In the organic electroluminescent element of the present invention, each layer constituting the organic layer can be suitably formed by any of a dry film forming method such as a vapor deposition method and a sputtering method, a transfer method, and a printing method.

-Light emitting layer-
The light-emitting layer receives holes from the anode, the hole injection layer, or the hole transport layer when an electric field is applied, receives electrons from the cathode, the electron injection layer, or the electron transport layer, and recombines holes and electrons. It is a layer which has the function to provide and to emit light.
The light emitting layer in the present invention may be composed of only a light emitting material, or may be a mixed layer of a host material and a light emitting material. The light emitting material may be a fluorescent light emitting material or a phosphorescent light emitting material, and the dopant may be one kind or two or more kinds. The host material is preferably a charge transport material. The host material may be one kind or two or more kinds, and examples thereof include a configuration in which an electron transporting host material and a hole transporting host material are mixed. Further, the light emitting layer may include a material that does not have charge transporting properties and does not emit light. The light emitting layer is preferably one using the complex of the present invention as a light emitting material, and more preferably composed of at least one kind of host material and the complex of the present invention.
In addition, the light emitting layer may be a single layer or two or more layers, and each layer may emit light in different emission colors.

Examples of fluorescent light-emitting materials that can be used in the present invention include, for example, benzoxazole derivatives, benzimidazole derivatives, benzothiazole derivatives, styrylbenzene derivatives, polyphenyl derivatives, diphenylbutadiene derivatives, tetraphenylbutadiene derivatives, naphthalimide derivatives, coumarin derivatives. , Condensed aromatic compounds, perinone derivatives, oxadiazole derivatives, oxazine derivatives, aldazine derivatives, pyralidine derivatives, cyclopentadiene derivatives, bisstyrylanthracene derivatives, quinacridone derivatives, pyrrolopyridine derivatives, thiadiazolopyridine derivatives, cyclopentadiene derivatives, styryl Complexes of amine derivatives, diketopyrrolopyrrole derivatives, aromatic dimethylidin compounds, 8-quinolinol derivatives and pyromethene derivatives Various complexes represented, polythiophene, polyphenylene, polyphenylene vinylene polymer compounds include compounds such as organic silane derivatives.

In addition to the complex of the present invention, examples of the phosphorescent material that can be used in the present invention include complexes containing transition metal atoms or lanthanoid atoms.
Although it does not specifically limit as a transition metal atom, Preferably, ruthenium, rhodium, palladium, tungsten, rhenium, osmium, iridium, and platinum are mentioned, More preferably, they are rhenium, iridium, and platinum.
Examples of lanthanoid atoms include lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. Among these lanthanoid atoms, neodymium, europium, and gadolinium are preferable.

Examples of the ligand of the complex include, for example, G. Wilkinson et al., Comprehensive Coordination Chemistry, Pergamon Press, 1987, H. Yersin, “Photochemistry and Photophysics of Coordination Compounds”, Springer-Verlag, 1987, Akio Yamamoto Examples of the ligands described in the book “Organic Metal Chemistry-Fundamentals and Applications-” published in 1982 by Hankabosha.
Specific ligands are preferably halogen ligands (preferably chlorine ligands), nitrogen-containing heterocyclic ligands (eg, phenylpyridine, benzoquinoline, quinolinol, bipyridyl, phenanthroline, etc.), diketones Ligand (for example, acetylacetone), carboxylic acid ligand (for example, acetic acid ligand), carbon monoxide ligand, isonitrile ligand, cyano ligand, more preferably nitrogen-containing Heterocyclic ligand. The complex may have one transition metal atom in the compound, or may be a so-called binuclear complex having two or more. Different metal atoms may be contained at the same time.

  The phosphorescent material is preferably contained in the light emitting layer in an amount of 0.1 to 40% by mass, and more preferably 0.5 to 20% by mass.

  In addition to the complex of the present invention, the host material contained in the light emitting layer in the present invention includes, for example, those having a carbazole skeleton, those having a diarylamine skeleton, those having a pyridine skeleton, those having a pyrazine skeleton Examples thereof include those having a triazine skeleton and those having an arylsilane skeleton, and materials exemplified in the sections of a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer described later.

  Although the thickness of a light emitting layer is not specifically limited, Usually, it is preferable that they are 1 nm-500 nm, it is more preferable that they are 5 nm-200 nm, and it is still more preferable that they are 10 nm-100 nm.

-Hole injection layer, hole transport layer-
The hole injection layer and the hole transport layer are layers having a function of receiving holes from the anode or the anode side and transporting them to the cathode side. Specifically, the hole injection layer and the hole transport layer are carbazole derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamines. Derivatives, amino-substituted chalcone derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic tertiary amine compounds, styrylamine compounds, aromatic dimethylidin compounds, porphyrin compounds, organosilane derivatives, carbon And the like.

The thicknesses of the hole injection layer and the hole transport layer are each preferably 500 nm or less from the viewpoint of lowering the driving voltage.
The thickness of the hole transport layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and still more preferably 10 nm to 100 nm. In addition, the thickness of the hole injection layer is preferably 0.1 nm to 200 nm, more preferably 0.5 nm to 100 nm, and still more preferably 1 nm to 100 nm.
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.

-Electron injection layer, electron transport layer-
The electron injection layer and the electron transport layer are layers having a function of receiving electrons from the cathode or the cathode side and transporting them to the anode side. Specifically, the electron injection layer and the electron transport layer are triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, fluorenone derivatives, anthraquinodimethane derivatives, anthrone derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, Carbodiimide derivatives, fluorenylidenemethane derivatives, distyrylpyrazine derivatives, aromatic tetracarboxylic anhydrides such as naphthalene and perylene, phthalocyanine derivatives, 8-quinolinol derivative complexes, metal phthalocyanines, benzoxazoles and benzothiazoles as ligands It is preferably a layer containing various complexes typified by the complex to be prepared, an organosilane derivative, and the like.

The thicknesses of the electron injection layer and the electron transport layer are each preferably 500 nm or less from the viewpoint of lowering the driving voltage.
The thickness of the electron transport layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and still more preferably 10 nm to 100 nm. In addition, the thickness of the electron injection layer is preferably 0.1 nm to 200 nm, more preferably 0.2 nm to 100 nm, and still more preferably 0.5 nm to 50 nm.
The electron injection layer and the electron transport layer may have a single-layer structure made of one or more of the materials described above, or may have a multilayer structure made up of a plurality of layers having the same composition or different compositions.

-Hole blocking layer-
The hole blocking layer is a layer having a function of preventing holes transported from the anode side to the light emitting layer from passing through to the cathode side. In the present invention, a hole blocking layer can be provided as an organic layer adjacent to the light emitting layer on the cathode side.
Examples of the organic compound constituting the hole blocking layer include aluminum complexes such as BAlq, triazole derivatives, phenanthroline derivatives such as BCP, and the like.
The thickness of the hole blocking layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and still more preferably 10 nm to 100 nm.
The hole blocking layer may have a single layer structure made of one or more of the materials described above, or may have a multilayer structure made of a plurality of layers having the same composition or different compositions.

<Protective layer>
In the present invention, the entire organic EL element may be protected by a protective layer.
As a material contained in the protective layer, any material may be used as long as it has a function of preventing materials that promote device deterioration such as moisture and oxygen from entering the device.
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 nitrides such as SiN _x and SiN _x O _y , metal fluorides such as MgF ₂ , LiF, AlF ₃ and CaF ₂ , polyethylene, polypropylene, polymethyl Monomer mixture containing methacrylate, polyimide, polyurea, polytetrafluoroethylene, polychlorotrifluoroethylene, polydichlorodifluoroethylene, copolymer of chlorotrifluoroethylene and dichlorodifluoroethylene, tetrafluoroethylene and at least one comonomer A copolymer obtained by copolymerization of a copolymer having a cyclic structure in the copolymer main chain. Copolymer, 1% by weight of the water absorbing water absorption material, water absorption of 0.1% or less of moisture-proof material, and the like.

  The method for forming the protective layer is not particularly limited, and for example, vacuum deposition, sputtering, reactive sputtering, MBE (molecular beam epitaxy), cluster ion beam, ion plating, plasma polymerization (high frequency) Excited 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>
The element of this invention may seal the whole element using a sealing container. You may enclose a water | moisture-content absorber or an inert liquid in the space between a sealing container and an 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.

  The element of the present invention obtains light emission by applying a direct current (which may include an alternating current component as necessary) voltage (usually 2 to 15 volts) or applying a direct current between the anode and the cathode. be able to.

  Regarding the driving method of the element of the present invention, JP-A-2-148687, JP-A-6-301355, JP-A-5-29080, JP-A-7-134558, JP-A-8-234665, and JP-A-8-214447, The driving methods described in Japanese Patent No. 2784615, US Pat. Nos. 5,828,429 and 6023308, etc. can be applied.

  The element of the present invention can be suitably used for display elements, displays, backlights, electrophotography, illumination light sources, recording light sources, exposure light sources, reading light sources, signs, signboards, interiors, optical communications, and the like.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these.
<Organic electroluminescent device>
(Comparative Example 1)
The cleaned ITO substrate is put in a vapor deposition apparatus, and NPD having the following structure is vapor-deposited by 50 nm, and CBP and PtOEP (compound described in US Pat. No. 6,303,238) having the following structure are vapor-deposited by 40 nm at a mass ratio of 10: 1. Further, 10 nm of BAlq having the following structure was deposited thereon, and 30 nm of Alq having the following structure was further deposited thereon. A patterned mask (with a light emission area of 4 mm × 5 mm) was placed on the obtained organic thin film, and after 3 nm of lithium fluoride was deposited, 60 nm of aluminum was deposited to prepare an organic EL device of Comparative Example 1. When a direct current voltage was applied to the obtained organic EL element, red light emission was observed.

(Example 1)
An organic EL device of Example 1 was produced in the same manner as Comparative Example 1 except that Exemplified Compound 1 of the present invention was used in place of PtOEP. When a DC constant voltage was applied to the obtained organic EL element, blue-green light emission was observed. The external quantum efficiency of the device of Example 1 was twice that of the device of Comparative Example 1. The luminance half time after driving the device of Example 1 at 10 V was 1.5 times that of the device of Comparative Example 1.

  From the above examples, it became clear that a highly efficient and highly durable organic EL device can be obtained by using the compound of the present invention.

Claims (1)

An organic electroluminescent device having at least one organic layer between a pair of electrodes, wherein the organic layer contains at least one compound represented by the following general formula (I).

(In the general formula (I), X ¹¹ , X ¹² and X ¹³ represent a phenyl group. Y ¹¹ represents a pyridyl group. L ¹ , L ² and L ⁴ represent a single bond, and L ³ represents dimethylmethylene. Represents a group or a diphenylmethylene group, n ¹ represents 0, and n ² , n ³ , and n ⁴ represent 1. Here, n ¹ is 0 when X ¹¹ and X ¹² are connected. It means not being done.)