JP5636244B2 - Organic electroluminescence device - Google Patents

Description

  The present invention relates to an organic electroluminescent device.

  As devices using organic materials, researches on organic electroluminescent elements (hereinafter also referred to as OLEDs and organic EL elements), transistors using organic semiconductors, and the like are being actively conducted. In particular, the organic electroluminescence device is expected to be developed as a lighting application as a solid light-emitting large-area full-color display device or an inexpensive large-area surface light source. In general, an organic electroluminescent element is composed of an organic layer including a light emitting layer and a pair of counter electrodes sandwiching the organic layer. When a voltage is applied to such an organic electroluminescence device, electrons are injected from the cathode and holes are injected from the anode into the organic layer. The electrons and holes recombine in the light emitting layer, and light is emitted by releasing energy as light when the energy level returns from the conduction band to the valence band.

An organic EL element can be produced by forming a light emitting layer and other organic layers by, for example, a dry method such as vapor deposition or a wet method such as coating. However, wet methods are attracting attention from the viewpoint of productivity. ing.
In Patent Document 1, an organic electroluminescence device having a high electroluminescence efficiency using a high T1 level of a triphenylene compound is obtained by forming a light emitting layer by a wet method and using a triphenylene compound as a host of the light emitting layer. It is described that However, when a triphenylene compound having a wide energy gap is used as the host of the light emitting layer, the efficiency of light emission of the organic EL element is low because of the low electron injection property from the electron transport layer (for example, Alq ₃ , Balq). It is a problem and needs improvement.

  Patent Document 2 discloses an organic electroluminescent device having an organic layer including a light emitting layer and a block layer adjacent to each other, wherein the light emitting layer contains a phosphorescent material and the block layer contains a triphenylene compound. An electroluminescent element is disclosed, which describes that the luminous efficiency and driving durability are improved. However, CBP (4,4′-bis (9H-carbazol-9-yl) biphenyl) is used as the host in the examples. In this case, although it can be formed as an amorphous film by a vacuum deposition method, In particular, there is a problem that CBP is easily crystallized due to a temperature rise or the like when driven at high luminance, and the luminous efficiency is lowered. When driving at high luminance with further improvement in luminous efficiency and driving durability. There is also a need for a host that is difficult to crystallize.

  Further, as a triphenylene compound, those that exhibit liquid crystallinity are known (also referred to as discotic liquid crystal). For example, Patent Document 3 includes a light-emitting discotic liquid crystal layer, so that luminous efficiency is high. It is disclosed that an organic EL element having excellent durability is provided.

JP 2009-1114068 A JP 2005-259472 A JP-A-10-321371

When a triphenylene compound having a wide energy gap is used as the host of the light emitting layer, the efficiency of light emission of the organic EL element is low due to the low electron injection property from the electron transport layer (for example, Alq ₃ , Balq). There is a need for improvement.

An object of the present invention is to solve the conventional problems and achieve the following objects.
That is, the present invention relates to an organic electroluminescent device using a triphenylene derivative exhibiting liquid crystallinity as a host material of a light-emitting layer, and has a solubility in an organic solvent due to liquid crystallinity, and the light emission efficiency and An object of the present invention is to provide an organic electroluminescence device having further improved durability.

  In view of the above situation, the present inventors have conducted intensive research. As a result, in an organic electroluminescent device having a light-emitting layer having a triphenylene derivative exhibiting liquid crystallinity and an electron transport layer, the light-emitting layer, the electron transport layer, In the meantime, it has been found that the above problem can be solved by having a triphenylene derivative capable of vapor deposition as a buffer layer.

  That is, the means for solving the problems are as follows.

[1] An organic electroluminescent device comprising a pair of electrodes composed of an anode and a cathode, a light emitting layer having a triphenylene derivative exhibiting liquid crystallinity, and an electron transport layer between the pair of electrodes,
An organic electroluminescent element comprising a triphenylene derivative capable of vapor deposition as a buffer layer between the light emitting layer and the electron transport layer.
[2] The electron affinity (Ea1) of the triphenylene derivative exhibiting liquid crystallinity of the light emitting layer, the electron affinity (Ea2) of the triphenylene derivative capable of vapor deposition of the buffer layer, and the electron affinity of the compound constituting the electron transport layer (Ea3)
Ea1 ≦ Ea2 <Ea3
The organic electroluminescent element as described in [1] above.
[3] The organic electroluminescence device according to [1] or [2], wherein the light emitting layer has a platinum complex.
[4] The organic electroluminescent element as described in [1] or [2] above, wherein the light emitting layer has a pyrene derivative.
[5] The triphenylene derivative capable of vapor deposition of the buffer layer is a compound having a structural unit represented by the following general formula (1), or a compound represented by the following general formula (3). Organic electroluminescent element as described in any one of said [1]-[4].

^(Wherein, R 1, ^{R 2} and ^{R 3} represents a substituent. These may be different from one another identical .N1, n2 and n3 each independently represents an integer of 0 to 4 .)

(In the formula, Ar represents a substituted or unsubstituted aryl group. Ar may be the same or different.)
[6] The triphenylene derivative capable of vapor deposition of the buffer layer is a compound having a structural unit represented by the general formula (1), and the compound is represented by the following general formula (2) [5] ] The organic electroluminescent element of description.

(In the formula, R ⁴ , R ⁵ , R ⁶ and R ⁷ represent substituents. These may be the same or different from each other. N4 and n5 each independently represents an integer of 0 to 4. Represents.)
[7] The organic electroluminescent element according to any one of [1] to [6], wherein the light emitting layer is formed by a wet method.
[8] The organic electroluminescent element according to any one of [1] to [7], wherein the buffer layer is formed by a vacuum deposition method.
[9] The organic electroluminescent element according to any one of [1] to [8], wherein the cathode is formed by a sputtering method.
[10] The organic electroluminescence device according to [9], wherein the cathode is an alloy of aluminum and lithium.

  ADVANTAGE OF THE INVENTION According to this invention, in the organic electroluminescent element using the triphenylene derivative which shows liquid crystallinity as a host material of a light emitting layer, the organic electroluminescent element which further improved the luminous efficiency and durability can be provided.

It is the schematic which shows an example of the layer structure of the organic electroluminescent element which concerns on this invention.

  Hereinafter, the present invention will be described in detail. In the present specification, “to” indicates a range including the numerical values described before and after the minimum and maximum values, respectively.

In the present invention, the substituent group A and the substituent group B are 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, isopropyl, 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 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 , 3-pentynyl, etc.), an aryl group (preferably having 6 to 30 carbon atoms, more preferably carbon 6 to 20, particularly preferably 6 to 12 carbon atoms, such as phenyl, p-methylphenyl, naphthyl, anthranyl, etc.), amino group (preferably 0 to 30 carbon atoms, more preferably 0 carbon atoms). -20, particularly preferably 0 to 10 carbon atoms, such as amino, methylamino, dimethylamino, diethylamino, dibenzylamino, diphenylamino, ditolylamino, etc.), 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, etc.), an aryloxy group (preferably 6 to 6 carbon atoms). 30 and more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms. Nyloxy, 1-naphthyloxy, 2-naphthyloxy, etc.), a heterocyclic oxy group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms). For example, pyridyloxy, pyrazyloxy, pyrimidyloxy, quinolyloxy, etc.), an acyl group (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 12 carbon atoms, 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 12 carbon atoms such as methoxycarbonyl, ethoxy Carbonyl, etc.), an aryloxycarbonyl group (preferably It has 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 ( An aromatic heterocyclic group is also included, preferably 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, Is, for example, a nitrogen atom, oxygen atom, sulfur atom, phosphorus atom, silicon atom, selenium atom, tellurium atom, specifically pyridyl, pyrazinyl, pyrimidyl, pyridazinyl, pyrrolyl, pyrazolyl, triazolyl, imidazolyl, oxazolyl, thiazolyl, And isoxazolyl, isothiazolyl, quinolyl, furyl, thienyl, selenophenyl, tellurophenyl, piperidyl, piperidino, morpholino, pyrrolidyl, pyrrolidino, benzoxazolyl, benzoimidazolyl, benzothiazolyl, carbazolyl group, azepinyl group, silolyl 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, and examples thereof include trimethylsilyl and triphenylsilyl). Ryloxy group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, particularly preferably 3 to 24 carbon atoms, such as trimethylsilyloxy, triphenylsilyloxy, etc.), phosphoryl group (for example, A diphenylphosphoryl group, a dimethylphosphoryl group, etc.). These substituents may be further substituted, and examples of the further substituent include a group selected from the substituent group A described above.
(Substituent group B)
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, isopropyl, 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 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 , 3-pentynyl, etc.), an aryl group (preferably having 6 to 30 carbon atoms, more preferably carbon 6 to 20, particularly preferably 6 to 12 carbon atoms, including, for example, phenyl, p-methylphenyl, naphthyl, anthranyl, etc.), cyano group, heterocyclic group (including aromatic heterocyclic group, Has 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, a sulfur atom, a phosphorus atom, a silicon atom, a selenium atom, and a tellurium atom. Is pyridyl, pyrazinyl, pyrimidyl, pyridazinyl, pyrrolyl, pyrazolyl, triazolyl, imidazolyl, oxazolyl, thiazolyl, isoxazolyl, isothiazolyl, quinolyl, furyl, thienyl, selenophenyl, tellurophenyl, piperidyl, piperidino, morpholino, pyrrolidyl, pyrrolidino, benzoxazolid Le, benzimidazo , Benzothiazolyl, carbazolyl group, azepinyl group, silylyl group, etc.) These substituents may be further substituted, and examples of further substituents include groups selected from the above substituent group A. Can do.

The organic electroluminescent device of the present invention is an organic electroluminescent device having a pair of electrodes composed of an anode and a cathode, a light emitting layer having a triphenylene derivative exhibiting liquid crystallinity, and an electron transport layer between the pair of electrodes. Thus, a triphenylene derivative capable of vapor deposition is provided as a buffer layer between the light emitting layer and the electron transport layer.
The reason why the organic electroluminescence device with improved luminous efficiency and durability is provided by the configuration of the device of the present invention is not clear, but is presumed as follows.
By using a triphenylene derivative exhibiting liquid crystallinity as the host material of the light emitting layer, the orientation of the host molecules is improved, the charge mobility is increased, and the organic electroluminescence device is aligned by being oriented in the horizontal direction of the substrate. It is presumed that the light extraction efficiency increases and low voltage driving becomes possible.
Further, between the light emitting layer having a liquid crystalline triphenylene derivative functioning as a host material and the electron transporting layer, the liquid crystallinity contained in the light emitting layer has the same or slightly higher electron affinity than the liquid crystalline triphenylene derivative. By using a possible triphenylene derivative in a buffer layer (hereinafter also referred to as an adjacent layer) between the light emitting layer and the electron transport layer, the adjacent layer assists injection of electrons from the electron transport layer to the light emitting layer. It is presumed that low voltage driving is possible by acting as a hole blocking layer as well as acting.
Further, in the lamination of the above layers, by adjoining an adjacent layer containing a compound similar to or the same kind as the compound contained in the light emitting layer, the bonding between the light emitting layer and the compound contained in the adjacent layer is improved, and these layers are improved. It is presumed that the luminous efficiency is improved by reducing the contact resistance at the interface. Further, it is presumed that by adjoining the adjacent layer containing a similar or similar compound to the light emitting layer, the effect of protecting the surface of the light emitting layer is produced and the durability is improved.
From the viewpoint of electron mobility, the light emitting layer of the present invention is preferably formed by a wet method described later, and the adjacent layer and the electron transport layer are formed by a dry method (preferably vacuum deposition method) described later. preferable. In the application / vapor deposition lamination, it is considered that the above-described effects of the present invention can be more satisfactorily achieved by laminating a compound similar to or similar to the application layer on the application / vapor deposition interface by the vapor deposition method and adjoining them.
Hereafter, each component contained in the organic electroluminescent element of this invention and its structure are demonstrated.

[1] Triphenylene derivative exhibiting liquid crystallinity As a triphenylene derivative exhibiting liquid crystallinity, a conventionally known discotic liquid crystalline triphenylene derivative can be used. For example, a triphenylene represented by the following general formula (TI) Derivatives can be mentioned. The triphenylene derivative exhibiting liquid crystallinity, it is preferable that the triphenylene derivative expressing a discotic nematic phase having a good monodomain property (N _D phase). The triphenylene derivative exhibiting liquid crystallinity in the light emitting layer functions as a host material. A triphenylene derivative exhibiting liquid crystallinity is hardly crystallized even when driven at high luminance. Further, the triphenylene derivative exhibiting liquid crystallinity is aligned, and has higher solubility in an organic solvent than a triphenylene derivative not exhibiting liquid crystallinity.

In the above general formula (T-I), R _T represents R _T ¹ —, R _T ¹ —O—, R _T ¹ —CO—O—, or R _T ¹ —O—CO—. Although all the compounds having these groups are not discotic liquid crystalline, an appropriate group that exhibits discotic liquid crystallinity can be selected and used based on known techniques. Examples of R _T ¹ include an alkyl group, an alkyl group in which a ring such as a phenylene group or a cyclohexylene group is combined, an oxygen group in which an oxygen atom is arranged between carbon and carbon of the alkyl group, and the like.

As R _T , specifically, R _T ² —, R _T ² —O—, R _T ² —O—R _T ³ —, R _T ² —O—R _T ³ —O—, R _T ² — O—Ph—COO—, R _T ² — (O—R _T ³ ) _nT —O—Ph—COO—, R _T ² —O—Ph—CH═CH—COO—, CH ₂ = CH—COO—R _T ³ —O—Ph—COO— may be mentioned. Here, R _T ² represents an alkyl group which may have a polymerizable group, R _T ³ represents an alkylene group, Ph represents a phenylene group which may have a substituent, n _T , Is a repeating number _of- (O-R _T ³ )-and represents an integer of 1 or more.

R _T ² represents an alkyl group which may have a polymerizable group, when having a polymerizable group, it is preferable from the viewpoint of the expression of the N _D phase having a polymerizable group at the top end of the alkyl group. Examples of the polymerizable group include an acrylic acid ester group, a methacrylic acid ester group, a crotonic acid ester group, and an epoxy group. From the viewpoint of polymerization speed, ease of synthesis, and cost, an acrylic acid ester group and a methacrylic acid ester group. Groups are preferred, and acrylate groups are more preferred.
Carbon number of the alkyl group part in the alkyl group which may have a polymerizable group represented by R _T ² is preferably in the range of 1-20, more preferably in the range of 1-15, and further Preferably it is the range of 3-10.
The number of carbon atoms of the alkylene group represented by R _T ³ is preferably in the range of 1 to 20, more preferably in the range of 1 to 15, and still more preferably in the range of 3 to 10.
Ph represents a phenylene group which may have a substituent group, includes as the substituent also be a halogen atom such as fluorine atom, an alkyl group, an alkoxy group, and the expression of the N _D phase From the viewpoint, an alkyl group is preferable. The number of carbon atoms of the alkyl group or alkoxy group as a substituent is preferably in the range of 1 to 20, more preferably in the range of 1 to 10, and still more preferably in the range of 1 to 6.
n _{T ^{is, - (O-R T 3}} ) - number of repetitions of the represents an integer of 1 or more. n _T is preferably an integer of 1 to 10, more preferably an integer from 1 to 6, more preferably an integer of 1 to 3.

The R _T, in terms of expression of the _{N D ^{phase, R T 2 -O-Ph-}} COO-, R T 2 - (O-R T 3) nT -O-Ph-COO-, R T 2 - O-Ph-CH = CH- COO- is ^{_{preferred, R T 2 -O-Ph-}} COO- are more preferred.

Triphenylene derivative represented by the above general formula (T-I) in that they express the N _D phase, it is preferably a triphenylene derivative represented by the following general formula (T-II).

In the above general formula (T-II), R _T ′ is R _T ² —O—Ph—CO—, R _T ² — (O—R _T ³ ) _nT —O—Ph—CO—, or R _T ^2. —O—Ph—CH═CH—CO— is represented. The definitions of R _T ² , Ph, R _T ³ , and n _T are synonymous with R _T ² , Ph, R _T ³ , and n _{T in} the general formula (TI). Specific examples and preferred ranges of R _T ² , Ph, R _T ³ , and n _{T in} the general formula (T-II) are the same as those in the general formula (T-I).

R _T ', since the expression of _{N D} phase is good, the following general formula (T-II-1) ~ It is more preferably represented by any one of (T-II-5).

In the general formulas (T-II-1) to (T-II-5), n and n ′ each independently represent an integer of 1 or more.
X _T represents a polymerizable group.

n represents an integer of 1 or more. n is preferably an integer of 1 to 20, more preferably an integer of 1 to 15, and still more preferably an integer of 3 to 10.
n ′ represents an integer of 1 or more. n ′ is preferably an integer of 1 to 10, more preferably an integer of 1 to 6, and still more preferably an integer of 1 to 3.
X _T represents a polymerizable group, and specific examples and preferred ranges are specific examples of the general formula (T-I) in which may have an alkyl group represented by R _T ² polymerizable groups and This is the same as the preferred range.

  Among the triphenylene derivatives exhibiting liquid crystallinity in the present invention, those that cause the liquid crystal phase to be expressed in the range of 20 ° C to 300 ° C are preferable. More preferably, it is 40 degreeC-280 degreeC, More preferably, it is 60 degreeC-250 degreeC. Here, the expression of the liquid crystal phase at 20 ° C. to 300 ° C. also means that the liquid crystal temperature range extends over 20 ° C. (for example, 10 ° C. to 22 ° C.) or 300 ° C. (for example, 298 ° C. to 310 ° C.). Including. The same applies to 40 ° C to 280 ° C and 60 ° C to 250 ° C.

  The content of the triphenylene derivative exhibiting liquid crystallinity in the light emitting layer of the present invention is preferably 15 to 97% by mass in the light emitting layer, more preferably 30 to 95% by mass, and 50 to 90% by mass. More preferably.

  Specific examples of the triphenylene derivative exhibiting liquid crystallinity are shown below, but the present invention is not limited thereto.

[2] Triphenylene derivative capable of vapor deposition The buffer layer (also referred to as an adjacent layer) between the light emitting layer and the electron transport layer according to the present invention contains a triphenylene derivative capable of vapor deposition. Here, “deposition is possible” means that the compound can be sublimated without being decomposed by vacuum evaporation to form a film. The sublimation temperature of the triphenylene derivative capable of vapor deposition is usually 200 ° C to 400 ° C, preferably 200 ° C to 350 ° C, more preferably 250 ° C to 350 ° C. The triphenylene derivative contained in the adjacent layer is not particularly limited as long as it can be deposited as described above, but is a compound having a structural unit represented by the following general formula (1) or the following general formula ( The compound represented by 3) is preferable from the viewpoint of durability.

^(Wherein, R 1, ^{R 2} and ^{R 3} represents a substituent. These may be different from one another identical .N1, n2 and n3 each independently represents an integer of 0 to 4 .)

(In the formula, Ar represents a substituted or unsubstituted aryl group. Ar may be the same or different.)

In the general formula (1), R ¹ , R ² and R ³ each independently represent a substituent. Examples of the substituent include an alkyl group (preferably having 1 to 8 carbon atoms, such as methyl, ethyl, iso-propyl, tert-butyl, n-octyl, cyclohexyl, etc.), an alkenyl group (preferably having 2 to 8 carbon atoms). Yes, such as vinyl, allyl, 2-butenyl, 3-pentenyl, etc., alkynyl groups (preferably having 2 to 8 carbon atoms, such as propargyl, 3-pentynyl, etc.), aryl groups (preferably having 6 to 12 carbon atoms) For example, phenyl, p-methylphenyl, biphenylyl and the like are mentioned, and phenyl is preferable, halogen atom (for example, fluorine), amino group (preferably having 0 to 20 carbon atoms, for example, amino, dimethylamino, diphenylamino) Etc.), alkoxy groups (preferably having 1 to 8 carbon atoms, such as methoxy, , Butoxy and the like), aryloxy group (preferably having 6 to 12 carbon atoms, such as phenoxy), acyl group (eg acetyl, benzoyl, pivaloyl etc.), alkoxycarbonyl group (eg methoxycarbonyl, ethoxycarbonyl etc.), aryl Oxycarbonyl group (eg, phenoxycarbonyl), acyloxy group (eg, acetoxy, benzoyloxy), acylamino group (eg, N-methylacetylamino, N-methylbenzoylamino), carbamoyl group (eg, diethylcarbamoyl, diphenylcarbamoyl, etc.) An alkylthio group (preferably having 1 to 12 carbon atoms, such as methylthio and ethylthio), an arylthio group (preferably having 6 to 12 carbon atoms, such as phenylthio), sulfo Group (for example, methanesulfonyl, benzenesulfonyl, etc.), heterocyclic group (for example, nitrogen atom, oxygen atom, sulfur atom, selenium atom, etc. as hetero atom, preferably imidazolyl, pyridyl, furyl, etc. having 1 to 20 carbon atoms, Thienyl, piperidyl, pyrrolyl, morpholino, carbazolyl and the like), silyl groups (dialkylsilyl groups and diarylsilyl groups are preferred, and diphenylsilyl groups are more preferred). Of these, alkyl groups, aryl groups, halogen atoms, alkoxy groups, amino groups, and silyl groups are preferred from the viewpoint of durability. R ¹ , R ² and R ³ may be a triphenylene group bonded via a linking group or directly. Examples of the linking group include an aromatic ring, an aromatic heterocycle, a silicon atom, a nitrogen atom, a carbon atom, and combinations of two or more thereof, and an aromatic ring is preferable. The triphenylene group may further have a substituent, and preferable substituents are the same as the preferable substituents of R ¹ , R ² and R ³ in the general formula (1).

R ¹ , R ² and R ³ may be the same or different from each other.
n1, n2 and n3 each independently represents an integer of 0 to 4. From the viewpoint of electron mobility, n1, n2 and n3 are each independently preferably an integer of 0 to 2, more preferably 0 or 1.
The structural unit that can be represented by the general formula (1) works effectively in the present invention, but a compound having two or more structural units in one molecule can be used more preferably.

  Of the compounds having the structural unit represented by the general formula (1), compounds that can be particularly preferably used are compounds represented by the following general formula (2).

(In the formula, R ⁴ , R ⁵ , R ⁶ and R ⁷ represent substituents. These may be the same or different from each other. N4 and n5 each independently represents an integer of 0 to 4. Represents.)

In the general formula (2), R ⁴ , R ⁵ , R ⁶ and R ⁷ each independently represent a substituent. Specific examples and preferred ranges of the substituents represented by R ⁴ , R ⁵ , R ⁶ and R ⁷ include specific examples of the substituents represented by R ¹ , R ² and R ³ in the general formula (1) and This is the same as the preferred range.

  n4 and n5 each independently represents an integer of 0 to 4. From the viewpoint of electron mobility, n4 and n5 are each independently preferably an integer of 0 to 2, more preferably 0 or 1.

  The T1 energy of the triphenylene compound used in the present invention including the compound having the structural unit represented by the general formula (1) and the compound represented by the general formula (2) is preferably 59 kcal / mol or more, More preferably, it is 60 kcal / mol or more. The T1 energy can be calculated from the long wavelength end of the phosphorescence spectrum.

  Next, specific examples of the compound having the structural unit represented by the general formula (1) or the compound represented by the general formula (2) are shown, but the present invention is not limited thereto.

  Next, a method for producing the compound having the structural unit represented by the general formula (1) and the compound represented by the general formula (2) will be described. These triphenylene compounds can be synthesized by utilizing various known aromatic carbon-carbon bond formation reactions and the like. For example, Organic Synthesis Reaction Guide (John Wiley & Sons, Inc.) p. 617-p. 643 and Comprehensive Organic Transformation (VCH) p. 5-p. 103 can be synthesized using the technique described in 103.

In the general formula (3), Ar represents a substituted or unsubstituted aryl group. The substituted or unsubstituted aryl group represented by Ar preferably has 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, and particularly preferably 6 to 12 carbon atoms. Examples of the aryl skeleton in the substituted or unsubstituted aryl group include a benzene ring, a naphthalene ring, and an anthracene ring, and a benzene ring is preferable. Moreover, as a substituent which an aryl group has, it is the same as that of the substituent represented by R < ¹ >, R < ² > and R < ³ > in the said General formula (1).
Examples of Ar include a phenyl group, a p-methylphenyl group, a naphthyl group, and an anthranyl group, and a phenyl group, a p-methylphenyl group, and a naphthyl group are preferable, and a phenyl group is most preferable.

  Next, although the specific example of a compound represented by General formula (3) is shown, this invention is not limited to these.

  The content of the triphenylene derivative capable of being deposited in the buffer layer (adjacent layer) of the present invention is preferably 30 to 100% by mass, more preferably 60 to 100% by mass, and 90 to 100% by mass in the light emitting layer. % Is more preferable, and 100% by mass is most preferable.

[3] Luminescent material In the organic electroluminescent element of the present invention, the luminescent layer contains a luminescent material. Examples of the light-emitting material include phosphorescence emission described in detail in paragraph numbers [0100] to [0164] of JP-A-2008-270736 and paragraph numbers [0088] to [0090] of JP-A-2007-266458. Materials and fluorescent materials can be used.
In the organic electroluminescent device of the present invention, the light emitting layer contains a triphenylene derivative exhibiting liquid crystallinity, and since the triphenylene derivative is oriented, it is necessary to use a light emitting material having high planarity to the outside. It is preferable from the viewpoint of light extraction efficiency. Examples of the phosphorescent light emitting material having high planarity include platinum complexes, and examples of the fluorescent light emitting material having high planarity include pyrene derivatives, perylene derivatives, rubrene, and the like. From the viewpoint of light emission). That is, in the organic electroluminescent element of the present invention, the light emitting layer preferably has a platinum complex or a pyrene derivative from the viewpoint of light extraction efficiency to the outside.
Hereinafter, platinum complexes and pyrene derivatives that are preferably included in the light emitting layer will be described.

[3-1] Platinum complex The platinum complex is preferably a platinum complex represented by the following general formula (C-1).

(In the formula, Q ¹ , Q ² , Q ³ and Q ⁴ each independently represent a ligand coordinated to Pt. L ¹ , L ² and L ³ are each independently a single bond or a divalent linking group. Represents.)

General formula (C-1) is demonstrated. Q ¹ , Q ² , Q ³ and Q ⁴ each independently represent a ligand coordinated to Pt. At this time, the bond between Q ¹ , Q ² , Q ³ and Q ⁴ and Pt may be any of a covalent bond, an ionic bond, a coordinate bond, and the like. As an atom couple | bonded with Pt in Q < ¹ >, Q < ² >, Q < ³ > and Q < ⁴ >, a carbon atom, a nitrogen atom, an oxygen atom, a sulfur atom, and a phosphorus atom are preferable, and in Q < ¹ >, Q < ² >, Q < ³ > and Q < ⁴ > Of the atoms bonded to Pt, at least one is preferably a carbon atom, more preferably two are carbon atoms, particularly preferably two are carbon atoms and two are nitrogen atoms.
Q ¹ , Q ² , Q ³ and Q ⁴ bonded to Pt by a carbon atom may be an anionic ligand or a neutral ligand, and the anionic ligand is a vinyl ligand, Aromatic hydrocarbon ring ligand (eg benzene ligand, naphthalene ligand, anthracene ligand, phenanthrene ligand), heterocyclic ligand (eg furan ligand, thiophene ligand, pyridine) Ligand, pyrazine ligand, pyrimidine ligand, pyridazine ligand, triazine ligand, thiazole ligand, oxazole ligand, pyrrole ligand, imidazole ligand, pyrazole ligand, triazole And a condensed ring containing them (for example, quinoline ligand, benzothiazole ligand, etc.). A carbene ligand is mentioned as a neutral ligand.
Q ¹ , Q ² , Q ³ and Q ⁴ bonded to Pt with a nitrogen atom may be neutral ligands or anionic ligands, and as neutral ligands, nitrogen-containing aromatic hetero Ring ligand (pyridine ligand, pyrazine ligand, pyrimidine ligand, pyridazine ligand, triazine ligand, imidazole ligand, pyrazole ligand, triazole ligand, oxazole ligand, Examples include thiazole ligands and condensed rings containing them (for example, quinoline ligands, benzimidazole ligands), amine ligands, nitrile ligands, and imine ligands. Examples of anionic ligands include amino ligands, imino ligands, nitrogen-containing aromatic heterocyclic ligands (pyrrole ligands, imidazole ligands, triazole ligands and condensed rings containing them) (For example, indole ligand, benzimidazole ligand, etc.)).
Q ¹ , Q ² , Q ³ and Q ⁴ bonded to Pt with an oxygen atom may be neutral ligands or anionic ligands, and neutral ligands are ether ligands, Examples include ketone ligands, ester ligands, amide ligands, oxygen-containing heterocyclic ligands (furan ligands, oxazole ligands and condensed rings containing them (benzoxazole ligands, etc.)). It is done. Examples of the anionic ligand include an alkoxy ligand, an aryloxy ligand, a heteroaryloxy ligand, an acyloxy ligand, a silyloxy ligand, and the like.
Q ¹ , Q ² , Q ³ and Q ⁴ bonded to Pt with a sulfur atom may be neutral ligands or anionic ligands, and neutral ligands include thioether ligands, Examples include thioketone ligands, thioester ligands, thioamide ligands, sulfur-containing heterocyclic ligands (thiophene ligands, thiazole ligands and condensed rings containing them (such as benzothiazole ligands)). It is done. Examples of the anionic ligand include an alkyl mercapto ligand, an aryl mercapto ligand, and a heteroaryl mercapto ligand.
Q ¹ , Q ² , Q ³ and Q ⁴ bonded to Pt with a phosphorus atom may be neutral ligands or anionic ligands, and neutral ligands include phosphine ligands, Examples include phosphate ester ligands, phosphite ester ligands, and phosphorus-containing heterocyclic ligands (phosphinin ligands, etc.). Anionic ligands include phosphino ligands and phosphinyl ligands. And phosphoryl ligands.
The groups represented by Q ¹ , Q ² , Q ^3, and Q ⁴ may have a substituent, and those listed as the substituent group A can be appropriately applied as the substituent. Moreover, substituents may be connected to each other (when Q ³ and Q ⁴ are connected, a Pt complex of a cyclic tetradentate ligand is formed).

The group represented by Q ¹ , Q ² , Q ³ and Q ⁴ is preferably an aromatic hydrocarbon ring ligand bonded to Pt with a carbon atom, and an aromatic heterocyclic ligand bonded to Pt with a carbon atom. A nitrogen-containing aromatic heterocyclic ligand that binds to Pt with a nitrogen atom, an acyloxy ligand, an alkyloxy ligand, an aryloxy ligand, a heteroaryloxy ligand, a silyloxy ligand, and more Preferably, an aromatic hydrocarbon ring ligand bonded to Pt by a carbon atom, an aromatic heterocyclic ligand bonded to Pt by a carbon atom, a nitrogen-containing aromatic heterocyclic ligand bonded to Pt by a nitrogen atom , An acyloxy ligand, an aryloxy ligand, more preferably an aromatic hydrocarbon ring ligand bonded to Pt with a carbon atom, an aromatic heterocyclic ligand bonded to Pt with a carbon atom, a nitrogen atom Containing Pt Containing aromatic heterocyclic ligand, an acyloxy ligand.

L ¹ , L ² and L ³ represent a single bond or a divalent linking group. Examples of the divalent linking group represented by L ¹ , L ² and L ³ include alkylene groups (methylene, ethylene, propylene, etc.), arylene groups (phenylene, naphthalenediyl), heteroarylene groups (pyridinediyl, thiophenediyl, etc.) ), Imino group (—NR—) (such as phenylimino group), oxy group (—O—), thio group (—S—), phosphinidene group (—PR—) (such as phenylphosphinidene group), silylene group (-SiRR'-) (dimethylsilylene group, diphenylsilylene group, etc.), or a combination of these. These linking groups may further have a substituent. R and R ¹ each independently represents a substituent.
From the viewpoint of the stability of the complex and the emission quantum yield, L ² and L ³ are preferably a single bond, an alkylene group, an arylene group, a heteroarylene group, an imino group, an oxy group, a thio group, or a silylene group, and more preferably. Is a single bond, an alkylene group, an arylene group or an imino group, more preferably a single bond, an alkylene group or an arylene group, more preferably a single bond, a methylene group or a phenylene group, still more preferably a single bond, Di-substituted methylene group, more preferably a single bond, dimethylmethylene group, diethylmethylene group, diisobutylmethylene group, dibenzylmethylene group, ethylmethylmethylene group, methylpropylmethylene group, isobutylmethylmethylene group, diphenylmethylene group, Methylphenylmethylene group, cyclohexanediyl group, cyclopen Njiiru group, fluorenediyl group, a fluoromethyl methylene group, particularly preferably a single bond, a dimethylmethylene group, a diphenylmethylene group, a cyclohexane diyl group, most preferably a single bond.

L ¹ is preferably an alkylene group, an arylene group, a heteroarylene group, an imino group, an oxy group, a thio group or a silylene group, more preferably an alkylene group, an arylene group or an imino group, still more preferably an alkylene group or an imino group. More preferably a methylene group or an imino group. These may have a substituent, and as the substituent, those exemplified as the substituent group A can be applied.
L ¹ is more preferably a single bond, a disubstituted methylene group, or an arylimino group, and more preferably a dimethylmethylene group, a diethylmethylene group, a diisobutylmethylene group, a dibenzylmethylene group, an ethylmethylmethylene group, or a methylpropylmethylene group. , Isobutylmethylmethylene group, diphenylmethylene group, methylphenylmethylene group, cyclohexanediyl group, cyclopentanediyl group, fluorenediyl group, fluoromethylmethylene group, phenylimino group, 4-t-butylphenylimino group, 3,5 -A di-t-butylphenylimino group, particularly preferably a dimethylmethylene group, a diphenylmethylene group, a cyclohexanediyl group, or a 3,5-di-t-butylphenylimino group.

  Of the platinum complexes represented by the general formula (C-1), a platinum complex represented by the following general formula (C-2) is more preferable.

(In the formula, L ²¹ represents a single bond or a divalent linking group. A ²¹ , A ²² , B ²¹ , and B ²² each independently represent a carbon atom or a nitrogen atom, but two or more represent a nitrogen atom. Z ²¹ and Z ²² each independently represent a benzene ring or a nitrogen-containing aromatic heterocycle, and Z ²³ and Z ²⁴ each independently represent a benzene ring or a nitrogen-containing aromatic heterocycle.

General formula (C-2) is demonstrated. L ²¹ has the same meaning as ^{L 1} in the general formula (C-1), and the preferred ranges are also the same.

A ²¹ , A ²² , B ²¹ and B ²² each independently represent a carbon atom or a nitrogen atom, but preferably two or more represent a nitrogen atom, preferably two or three represent a nitrogen atom, and two represent a nitrogen atom. Is more preferable. From the viewpoint of the stability of the complex, it is preferable to represent A ²¹ and A ²² nitrogen atoms, or that B ²¹ and B ²² are nitrogen atoms.

Z ²¹ , Z ²² , Z ²³ and Z ²⁴ each independently represent a benzene ring or a nitrogen-containing aromatic heterocycle. Examples of the nitrogen-containing aromatic heterocycle represented by Z ²¹ , Z ²² , Z ²³ , and Z ²⁴ include a pyridine ring, a pyrimidine ring, a pyrazine ring, a pyridazine ring, a triazine ring, an imidazole ring, a pyrazole ring, an oxazole ring, and a thiazole ring. , Triazole ring, oxadiazole ring, thiadiazole ring, and the like. From the viewpoint of stability of the complex, emission wavelength control and emission quantum yield, the ring represented by Z ²³ and Z ²⁴ is preferably a benzene ring, a pyridine ring, a pyrazine ring, an imidazole ring, a pyrazole ring, or a thiophene ring, More preferred are a benzene ring, a pyridine ring and a pyrazole ring, and still more preferred are a benzene ring and a pyridine ring.

The benzene ring and nitrogen-containing aromatic heterocycle represented by Z ²¹ , Z ²² , Z ²³ , and Z ²⁴ may have a substituent, and examples of the substituent on the carbon atom include the substituent group A. The substituent group B is applicable as a substituent on the nitrogen atom.

  The substituent on carbon is preferably an alkyl group, trifluoroalkyl group, aryl group, heterocyclic group, dialkylamino group, diarylamino group, alkoxy group, aryloxy group, silyl group, cyano group, or halogen atom. , An alkyl group, a trifluoroalkyl group, an aryl group, a heterocyclic group, a diarylamino group, an alkoxy group, a cyano group, or a halogen atom is more preferable, and an alkyl group, an alkoxy group, a fluorine atom, or a cyano group is still more preferable.

The alkyl group represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, and may have a linear, branched, or cyclic structure. As said alkyl group, C1-C12 is preferable, For example, a methyl group, an octyl group, a decyl group, a dodecyl group, t-butyl group, t-amyl group, s-butyl group etc. are mentioned.
The aryl group represents a substituted or unsubstituted aryl group having 6 to 10 carbon atoms and may be condensed, and examples thereof include a phenyl group, a toluyl group, and a naphthyl group.
The trifluoroalkyl group is preferably a trifluoromethyl group.
The alkoxy group represents a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, and may have a linear, branched, or cyclic structure. The alkoxy group preferably has 1 to 12 carbon atoms, and examples thereof include a methoxy group, a butyloxy group, an octyloxy group, a decyloxy group, a dodecyloxy group, an s-octyloxy group, and a benzyloxy group.
The hetero ring group represents a substituted or unsubstituted nitrogen-containing aromatic hetero ring group having 6 to 10 carbon atoms, which may be condensed, such as a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, Examples thereof include a triazine ring and a carbazole ring, and a carbazole ring is preferable.
The diarylamino group represents a substituted or unsubstituted diarylamino group having 6 to 10 carbon atoms and may be condensed, and examples thereof include a diphenylamino group, a ditoluylamino group, and a dinaphthylamino group.
The dialkylamino group represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, and may have a linear, branched, or cyclic structure. The dialkylamino group preferably has 1 to 12 carbon atoms. Specifically, for example, a dimethylamino group, a diethylamino group, a dioctylamino group, a didecylamino group, a didodecylamino group, a dit-butylamino group, a dit -An amylamino group, a di s-butylamino group, etc. are mentioned.
The aryloxy group represents a substituted or unsubstituted aryloxy group having 6 to 10 carbon atoms and may be condensed, and examples thereof include a phenyloxy group, a toluyloxy group, and a naphthyloxy group.
The silyl group represents a silyl group substituted with a carbon atom having 3 to 24 carbon atoms, and may be any of a trialkylsilyl group, an aryldialkylsilyl group, an alkyldiarylsilyl group, and a triarylsilyl group. The silyl group preferably has 3 to 18 carbon atoms. Specific examples include a trimethylsilyl group, a t-butyldimethylsilyl group, a triphenylsilyl group, and a t-butyldiphenylsilyl group.
As the halogen atom, a fluorine atom is preferable.

Among these, from the viewpoint of aspect ratio, the above-mentioned substituent having a linear alkyl group and a linear alkyl group as a substituent is preferable.
The substituent is appropriately selected for controlling the emission wavelength and potential, but in the case of increasing the wavelength, an electron donating group and an aromatic ring group are preferable, for example, an alkyl group, a dialkylamino group, an alkoxy group, an aryl group, An aromatic heterocyclic group or the like is selected. In order to shorten the wavelength, an electron withdrawing group is preferable, and for example, a fluorine group, a cyano group, a trifluoroalkyl group, and the like are selected.

  The substituent on the nitrogen atom is preferably an alkyl group, an aryl group, or an aromatic heterocyclic group, and an alkyl group or an aryl group is preferable from the viewpoint of the stability of the complex.

  The substituents may be linked to each other to form a condensed ring. Examples of the ring formed include a benzene ring, a pyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidine ring, an imidazole ring, an oxazole ring, a thiazole ring, and a pyrazole. Ring, thiophene ring, furan ring and the like.

  Of the platinum complexes represented by the general formula (C-2), one of the more preferable embodiments is a platinum complex represented by the following general formula (C-3).

(In the formula, A ^{301 to} A ³¹³ each independently represent C—R or a nitrogen atom. R represents a hydrogen atom or a substituent. L ³¹ represents a single bond or a divalent linking group. Y, Z and M represent a carbon atom or a nitrogen atom, and one of Z and Y is a nitrogen atom.)

General formula (C-3) is demonstrated.
L ³¹ has the same meaning as L ²¹ in formula (C-2), and the preferred range is also the same.

A ^{301 to} A ³⁰⁶ each independently represent C—R or a nitrogen atom. R represents a hydrogen atom or a substituent. As the substituent represented by R, those exemplified as the substituent group A can be applied.
A ^{301 to} A ³⁰⁶ are preferably C—R, and Rs may be connected to each other to form a ring. When A ^{301 to} A ³⁰⁶ are C—R, R in A ³⁰² and A ³⁰⁵ is preferably a hydrogen atom, alkyl group, trifluoroalkyl group, aryl group, heterocyclic group, dialkylamino group, diarylamino group , An alkoxy group, an aryloxy group, a silyl group, a cyano group, or a halogen atom, a hydrogen atom, an alkyl group, a trifluoroalkyl group, an aryl group, a heterocyclic group, a diarylamino group, an alkoxy group, a cyano group, or A halogen atom is more preferable, a hydrogen atom, an alkyl group, an alkoxy group, or a cyano group is further preferable, and a hydrogen atom is particularly preferable. The alkyl group and aryl group may further have a substituent, and examples of the substituent include an alkyl group, an aryl group, a cyano group, an amino group, a halogen atom, and a fluoroalkyl group. -6 alkyl group, cyano group, amino group, halogen atom, fluoroalkyl group (preferably trifluoromethyl group), more preferably C1-6 alkyl group, halogen atom (preferably fluorine atom). is there. In the case where A ³⁰² and A ³⁰⁵ are C—R, R in the A ³⁰² and A ³⁰⁵ is preferably an aryl group from the viewpoint of improving the durability of the device, and a hydrogen atom or an alkyl group from the viewpoint of a short emission wavelength. An amino group, an alkoxy group, a fluorine group and a cyano group are preferred.
R in A ³⁰¹ , A ³⁰³ , A ³⁰⁴ and A ³⁰⁶ is preferably a hydrogen atom, an alkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a fluorine group or a cyano group, more preferably a hydrogen atom or an amino group. Group, alkoxy group, aryloxy group and fluorine group, particularly preferably a hydrogen atom.

A ³⁰⁷ , A ³⁰⁸ , A ³⁰⁹ and A ³¹⁰ each independently represent C—R or a nitrogen atom. R represents a hydrogen atom or a substituent. As the substituent represented by R, those exemplified as the substituent group A can be applied. When A ³⁰⁷ , A ³⁰⁸ , A ³⁰⁹ and A ³¹⁰ are C—R, R is preferably a hydrogen atom, an alkyl group, a trifluoroalkyl group, an aryl group, an aromatic heterocyclic group, a dialkylamino group, a diaryl. An amino group, an alkyloxy group, a cyano group, and a halogen atom, more preferably a hydrogen atom, an alkyl group, a trifluoroalkyl group, an aryl group, a dialkylamino group, a cyano group, a fluorine atom, still more preferably a hydrogen atom, An alkyl group, a trifluoromethyl group, and a fluorine atom; If possible, the substituents may be linked to form a condensed ring structure. When shifting the emission wavelength to the short wavelength side, A ³⁰⁸ is preferably a nitrogen atom.

In the general formula (C-3), the 6-membered ring formed from two carbon atoms and A ³⁰⁷ , A ³⁰⁸ , A ³⁰⁹ and A ³¹⁰ includes a benzene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, and a triazine. A ring, more preferably a benzene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring and a pyridazine ring, and particularly preferably a benzene ring and a pyridine ring. When the 6-membered ring is a pyridine ring, a pyrazine ring, a pyrimidine ring, or a pyridazine ring (particularly preferably a pyridine ring), a hydrogen atom present at a position where a metal-carbon bond is formed as compared with a benzene ring. Since acidity improves, it is advantageous at the point which becomes easier to form a metal complex.

A ³¹¹ , A ³¹² and A ³¹³ each independently represent C—R or a nitrogen atom. R represents a hydrogen atom or a substituent. As the substituent represented by R, those exemplified as the substituent group A can be applied. When A ³¹¹ , A ³¹² and A ³¹³ are C—R, R is preferably a hydrogen atom, an alkyl group, a trifluoroalkyl group, an aryl group, a heterocyclic group, a dialkylamino group, a diarylamino group, an alkoxy group. , Aryloxy group, cyano group, halogen atom, more preferably hydrogen atom, alkyl group, trifluoroalkyl group, aryl group, dialkylamino group, cyano group, fluorine atom, more preferably hydrogen atom, alkyl group , A trifluoromethyl group and a fluorine atom. If possible, the substituents may be linked to form a condensed ring structure.
At least one of A ³¹¹ , A ³¹² and A ³¹³ is preferably a nitrogen atom, and particularly preferably A ³¹¹ is a nitrogen atom.

  Of the platinum complexes represented by the general formula (C-3), one of more preferable embodiments is a platinum complex represented by the following general formula (C-3-1).

(In general formula (C-3-1), X, Y, Z, and M each independently represent a carbon atom or a nitrogen atom, and either Z or Y is a nitrogen atom, and Y is a nitrogen atom. In this case, X is a carbon atom, m, n, p and q each independently represents an integer of 0 to _3. Ar represents a substituted or unsubstituted aryl group, R _{1 to} R ₃ and R ₃₀ independently represents an alkyl group, an aryl group, an alkoxy group, an aryloxy group, a fluorine atom, a cyano group, a silyl group, or a heterocyclic group, and when m, n, p, or q is 2 or more, And may be connected to each other to form a cyclic structure, and each Q is independently a carbon atom or a nitrogen atom.)

General formula (C-3-1) is demonstrated.
m, n, p, and q each independently represents an integer of 0 to 3. Among these, m is preferably 0 to 2, more preferably 0 to 1, and still more preferably 0. n is preferably 0 to 2, more preferably 0 to 1, and still more preferably 0. p is preferably 0-2, more preferably 1-2. q is preferably 0 to 2, and more preferably 0 to 1.
Examples of the aryl group represented by Ar include a phenyl group and a naphthyl group, and a phenyl group is preferable. The aryl group represented by Ar may further have a substituent, and examples of the substituent include an alkyl group, an aryl group, a cyano group, an amino group, a halogen atom, and a fluoroalkyl group, preferably 1 to 6 carbon atoms. An alkyl group, a cyano group, an amino group, a halogen atom and a fluoroalkyl group (preferably a trifluoromethyl group), more preferably an alkyl group having 1 to 6 carbon atoms and a halogen atom (preferably a fluorine atom). Among these, from the viewpoint of aspect ratio, the above-mentioned substituent having a linear alkyl group and an alkyl group as a substituent is preferable.
More preferable examples of Ar include a phenyl group, a 4-t-butylphenyl group, and a 3,5-di-t-butylphenyl group.
R _{1 to} R ₃ and R ₃₀ are preferably the same as R in the general formula (C-3), and preferably R _{1 to} R ₂ are an alkyl group, an aryl group, a fluorine atom, Represents a cyano group and a silyl group. R ₃ is preferably a trifluoroalkyl group, a cyano group, or a halogen atom, and more preferably a trifluoroalkyl group. R ₃₀ is preferably a trifluoroalkyl group, a cyano group, or a halogen atom, more preferably a halogen atom, and particularly preferably a fluorine atom.
When m, n, p, q is 2 or more, they may be linked to each other to form a cyclic structure.

  Among the platinum complexes represented by the general formula (C-2), one of more preferable embodiments is a platinum complex represented by the following general formula (C-4).

(In General Formula (C-4), A ^{401 to} A ⁴¹⁴ each independently represents C—R or N. R represents a hydrogen atom or a substituent. L ⁴¹ represents a single bond or a divalent linking group. .)

General formula (C-4) is demonstrated.
A ^{401 to} A ⁴¹⁴ each independently represent C—R or N. R represents a hydrogen atom or a substituent.
Or as a substituent represented by R, what was mentioned as the said substituent group A is applicable.
A ^{401 to} A ⁴⁰⁶ are preferably C—R, and Rs may be connected to each other to form a ring. When A ^{401 to} A ⁴⁰⁶ are C—R, R in A ⁴⁰² and A ⁴⁰⁵ is preferably a hydrogen atom, an alkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a fluorine group, or a cyano group. More preferably a hydrogen atom, an amino group, an alkoxy group, an aryloxy group or a fluorine group, and particularly preferably a hydrogen atom or a fluorine group. R in A ⁴⁰¹ , A ⁴⁰³ , A ⁴⁰⁴ and A ⁴⁰⁶ is preferably a hydrogen atom, an alkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a fluorine group or a cyano group, more preferably a hydrogen atom or an amino group. Group, alkoxy group, aryloxy group and fluorine group, particularly preferably a hydrogen atom.
L ⁴¹ has the same meaning as L ^{1 in} formula (C-1), and the preferred range is also the same.

As A ^{407 to} A ⁴¹⁴ , in each of A ^{407 to} A ⁴¹⁰ and A ^{411 to} A ⁴¹⁴ , the number of N (nitrogen atoms) is preferably 0 to 2, and more preferably 0 to 1. When shifting the emission wavelength to the short wavelength side, either A ⁴⁰⁸ or A ⁴¹² is preferably an N atom, and both A ⁴⁰⁸ and A ⁴¹² are more preferably N atoms.
In the case where A ^{407 to} A ⁴¹⁴ represent C—R, R in A ⁴⁰⁸ and A ⁴¹² is preferably a hydrogen atom, an alkyl group, a trifluoroalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a fluorine group. A cyano group, more preferably a hydrogen atom, a trifluoroalkyl group, an alkyl group, an aryl group, a fluorine group or a cyano group, and particularly preferably a hydrogen atom, a phenyl group, a trifluoroalkyl group or a cyano group. . R in A ⁴⁰⁷ , A ⁴⁰⁹ , A ⁴¹¹ and A ⁴¹³ is preferably a hydrogen atom, an alkyl group, a trifluoroalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a fluorine group or a cyano group, more preferably Is a hydrogen atom, a trifluoroalkyl group, a fluorine group or a cyano group, particularly preferably a hydrogen atom, a phenyl group or a fluorine group. R in A ⁴¹⁰ and A ⁴¹⁴ is preferably a hydrogen atom or a fluorine group, and more preferably a hydrogen atom. When any of A ^{407 to} A ⁴⁰⁹ and A ^{411 to} A ⁴¹³ represents CR, Rs may be connected to each other to form a ring.

  Of the platinum complexes represented by the general formula (C-2), one of more preferable embodiments is a platinum complex represented by the following general formula (C-5).

(In General Formula (C-5), A ^{501 to} A ⁵¹² each independently represents C—R or N. R represents a hydrogen atom or a substituent. L ⁵¹ represents a single bond or a divalent linking group. Y and Z each independently represent a carbon atom or a nitrogen atom, and Z or Y is a nitrogen atom)

General formula (C-5) is demonstrated. A ^{501 to} A ⁵⁰⁶ and L ⁵¹ have the same meanings as A ^{401 to} A ⁴⁰⁶ and L ⁴¹ in the general formula (C-4), and preferred ranges thereof are also the same.

A ⁵⁰⁷ , A ⁵⁰⁸ , A ⁵⁰⁹ , A ⁵¹⁰ , A ⁵¹¹ and A ⁵¹² each independently represent C—R or N. R represents a hydrogen atom or a substituent. As the substituent represented by R, those exemplified as the substituent group A can be applied. When A ⁵⁰⁷ , A ⁵⁰⁸ , A ⁵⁰⁹ , A ⁵¹⁰ , A ⁵¹¹ and A ⁵¹² are C—R, R is preferably a hydrogen atom, an alkyl group, a trifluoroalkyl group, an aryl group, an aromatic heterocyclic group. , Dialkylamino group, diarylamino group, alkyloxy group, cyano group, halogen atom, more preferably hydrogen atom, alkyl group, trifluoroalkyl group, aryl group, dialkylamino group, cyano group, fluorine atom, Preferably, they are a hydrogen atom, an alkyl group, a trifluoromethyl group, or a fluorine atom. If possible, the substituents may be linked to form a condensed ring structure. At least one of A ⁵⁰⁷ , A ⁵⁰⁸ , A ⁵⁰⁹ , A ⁵¹⁰ , A ⁵¹¹ and A ⁵¹² is preferably N, and particularly preferably A ⁵¹⁰ or A ⁵⁰⁷ is N.

  Of the platinum complexes represented by the general formula (C-5), one of more preferable embodiments is a platinum complex represented by the following general formula (C-5-1).

(In General Formula (C-5-1), X, Y, and Z each independently represent a carbon atom or a nitrogen atom, and either Z or Y is a nitrogen atom, and Y is a nitrogen atom. When X is a carbon atom, m, n, p and q each independently represents an integer of 0 to 3. Ar represents a substituted or unsubstituted aryl group, and R _{1 to} R ₄ represent Each independently represents an alkyl group, an aryl group, an alkoxy group, an aryloxy group, a fluorine atom, a cyano group, a silyl group, or a heterocyclic group, and when m, n, p, and q are 2 or more, They may be linked together to form a ring structure.)

R ₁ and R ₂ have the same meanings as A ^{401 to} A ⁴⁰⁶ and L ⁴¹ in the general formula (C-4), and preferred ranges thereof are also the same.
R ₃ and R ₄ are preferably an alkyl group, a trifluoroalkyl group, an aryl group, an aromatic heterocyclic group, a dialkylamino group, a diarylamino group, an alkyloxy group, a cyano group, or a halogen atom, more preferably , An alkyl group, a trifluoroalkyl group, an aryl group, a dialkylamino group, a cyano group, and a fluorine atom, and more preferably an alkyl group, a trifluoromethyl group, and a fluorine atom. If possible, the substituents may be linked to form a condensed ring structure.
Ar is synonymous with Ar in formula (C-3-1), and preferred ones are also the same.
m, n, p, and q each independently represents an integer of 0 to 3. Among these, m is preferably 0 to 2, more preferably 0 to 1, and still more preferably 0. n is preferably 0 to 2, more preferably 0 to 1, and still more preferably 0. p is preferably 0 to 2, and more preferably 1. q is preferably 0 to 2, and more preferably 1.

  Of the platinum complexes represented by the general formula (C-2), one of more preferable embodiments is a platinum complex represented by the following general formula (C-6).

(In General Formula (C-6), X, Y, and Z each independently represent a carbon atom or a nitrogen atom, and when either Z or Y is a nitrogen atom and Y is a nitrogen atom, , X is a carbon atom, r, s, t, and u each independently represent an integer of 0 to 3. R _{5 to} R ₈ are each independently an alkyl group, aryl group, alkoxy group, aryl It represents an oxy group, a fluorine atom, a cyano group, a silyl group, or a heterocyclic group, and when r, s, t, and u are 2 or more, they may be linked to each other to form a cyclic structure. ₁ and W ₂ each independently represent an alkyl group, and may be bonded to each other to form a cyclic structure.

r, s, t, and u each independently represent an integer of 0 to 3. Among these, r is preferably 0 to 2, and more preferably 0 or 1. s is preferably 0 to 2, more preferably 0 or 1. t is preferably 0 or 1, and u is preferably 0 or 1.
R ₅ and R ₆ are preferably an alkyl group, an alkoxy group, an aryl group, a trifluoroalkyl group, or a halogen atom, and the aryl group may have an alkyl group as a substituent.
R ₇ and R ₈ are preferably an alkyl group, a trifluoroalkyl group, an aryl group, an aromatic heterocyclic group, a dialkylamino group, a diarylamino group, an alkyloxy group, a cyano group, or a halogen atom, and the aryl group is Preferably, the aryl group may have an alkyl group as a substituent. .
W ₁ and W ₂ are preferably alkyl groups having 1 to 6 carbon atoms, and examples thereof include a methyl group, an ethyl group, an isopropyl group, an n-propyl group, a t-butyl group, and the like. preferable. The alkyl groups may be linked to each other to form a cyclic structure (eg, cyclopentane, cyclohexane, cycloheptane, preferably cyclopropane).

  Among the platinum complexes represented by the general formula (C-1), another more preferable embodiment is a platinum complex represented by the following general formula (C-7).

(In the formula, L ⁶¹ represents a single bond or a divalent linking group. A ⁶¹ represents C—R or N. R represents a hydrogen atom or a substituent. Z ⁶¹ and Z ⁶² each independently contain nitrogen. .Z represents an aromatic heterocycle ⁶³ .Y in which represents a benzene ring or an aromatic heterocyclic ring is an anionic non-cyclic ligand that binds to Pt.)

General formula (C-7) is demonstrated. L ⁶¹ has the same meaning as L ^{1 in} formula (C-1), and the preferred range is also the same.

A ⁶¹ represents a carbon atom or a nitrogen atom. In view of the stability of the complex and the light emission quantum yield of the complex, A ⁶¹ is preferably a carbon atom.

Z ⁶¹ and Z ⁶² are synonymous with Z ²¹ and Z ²² in the general formula (C-2), respectively, and preferred ranges thereof are also the same. Z ⁶³ has the same meaning as Z ²³ in formula (C-2), and the preferred range is also the same.

Y is an anionic acyclic ligand that binds to Pt. An acyclic ligand is one in which atoms bonded to Pt do not form a ring in the form of a ligand. As an atom couple | bonded with Pt in Y, a carbon atom, a nitrogen atom, an oxygen atom, and a sulfur atom are preferable, a nitrogen atom and an oxygen atom are more preferable, and an oxygen atom is the most preferable.
A vinyl ligand is mentioned as Y couple | bonded with Pt by a carbon atom. Examples of Y bonded to Pt with a nitrogen atom include an amino ligand and an imino ligand. Examples of Y bonded to Pt with an oxygen atom include an alkoxy ligand, an aryloxy ligand, a heteroaryloxy ligand, an acyloxy ligand, a silyloxy ligand, a carboxyl ligand, a phosphate ligand, Examples thereof include sulfonic acid ligands. Examples of Y bonded to Pt with a sulfur atom include alkyl mercapto ligands, aryl mercapto ligands, heteroaryl mercapto ligands, thiocarboxylic acid ligands, and the like.
The ligand represented by Y may have a substituent, and those exemplified as the substituent group A can be appropriately applied as the substituent. Moreover, substituents may be connected to each other.

  The ligand represented by Y is preferably a ligand bonded to Pt with an oxygen atom, more preferably an acyloxy ligand, an alkyloxy ligand, an aryloxy ligand, a heteroaryloxy ligand. , A silyloxy ligand, and more preferably an acyloxy ligand.

  Of the platinum complexes represented by the general formula (C-7), one of more preferred embodiments is a platinum complex represented by the following general formula (C-8).

(In the general formula (C-8), A ^{701 to} A ⁷¹⁰ each independently represents C—R or N. R represents a hydrogen atom or a substituent. L ⁷¹ represents a single bond or a divalent linking group. Y is an anionic acyclic ligand that binds to Pt.)

General formula (C-8) is demonstrated. L ⁷¹ has the same meaning as L ^{61 in} formula (C-6), and the preferred range is also the same. A ^{701 to} A ⁷¹⁰ have the same meanings as A ^{401 to} A ⁴¹⁰ in formula (C-4), and preferred ranges thereof are also the same. Y has the same meaning as that in formula (C-6), and the preferred range is also the same.

  Among the platinum complexes represented by the general formula (C-1), one of other preferable embodiments is a platinum complex represented by the following general formula (C-9).

(In General Formula (C-9), R _{9 to} R ₁₆ each independently represent a hydrogen atom, an alkyl group, an aryl group, a silyl group, or a heterocyclic group, and R ₉ and R ₁₁ , R ₁₁ and R ₁₂ , R ₁₂ and R ₁₀ , R ₁₄ and R ₁₅ , R ₁₃ and R ₁₆ may be independently bonded to each other to form a cyclic structure.)

R ₉ and R ₁₁ , R ₁₁ and R ₁₂ , R ₁₂ and R ₁₀ , R ₁₄ and R ₁₅ , and R ₁₃ and R ₁₆ are preferably bonded to each other to form a cyclic structure. More preferably, R ₉ and R ₁₁ , R ₁₂ and R ₁₀ , R ₁₄ and R ₁₅ , and R ₁₃ and R ₁₆ are independently bonded to each other to form a cyclic structure.
The cyclic structures formed by combining R ₉ and R ₁₁ , R ₁₁ and R ₁₂ , R ₁₂ and R ₁₀ , R ₁₄ and R ₁₅ , R ₁₃ and R ₁₆ include benzene ring, naphthalene ring, pyridine ring , A pyrazine ring, a pyrimidine ring, a pyridazine ring, and a triazine ring, and more preferably a benzene ring or a naphthalene ring.
R ₁₄ and R ₁₅ , R ₁₁ and R ₁₂ , R ₁₃ and R ₁₆ are preferably bonded to each other to form a cyclic structure.
The cyclic structure may further have a substituent, and as the further substituent, those exemplified as the substituent group A can be applied, and an alkyl group and an alkoxy group are preferable, and an alkyl having 1 to 20 carbon atoms is preferable. Group, a C1-C20 alkoxy group is more preferable, a C5-C15 alkyl group and a C5-C15 alkoxy group are still more preferable.

  Specific examples of the platinum complex represented by the general formula (C-1) include [0143] to [0152], [0157] to [0158], and [0162] to [0168] of JP-A-2005-310733. The compounds described in JP-A-2006-256999, [0065] to [0083], the compounds described in JP-A-2006-93542, [0065] to [0090], JP-A-2007-73891 Nos. [0063] to [0071], No. 2007-324309, No. 0079 to [0083], No. 2006-93542 No. [0065] to [0090] The compounds described in JP-A-2007-96255, [0055] to [0071], JP-A-2006-313796 0043] include - [0046], platinum complexes exemplified other following can be mentioned. In addition, the alkyl group and the alkyl group in the exemplary compound include a linear alkyl group, a branched alkyl group, and a cycloalkyl group, and preferably a linear alkyl group.

Examples of the platinum complex compound represented by the general formula (C-1) include Journal of Organic Chemistry 53,786, (1988), G.S. R. Newkome et al. ), Page 789, method described in left line 53 to right line 7, line 790, method described in left line 18 to line 38, method 790, method described in right line 19 line to line 30 and The combination, Chemische Berichte 113, 2749 (1980), H.C. Lexy et al.), Page 2752, lines 26-35, and the like.
For example, a ligand or a dissociated product thereof and a metal compound are mixed with a solvent (for example, a halogen solvent, an alcohol solvent, an ether solvent, an ester solvent, a ketone solvent, a nitrile solvent, an amide solvent, a sulfone solvent, In the presence of a sulfoxide solvent, water, etc., or in the absence of a solvent, in the presence of a base (inorganic and organic bases such as sodium methoxide, t-butoxypotassium, triethylamine, potassium carbonate, etc.) Or in the absence of a base, at room temperature or below, or by heating (in addition to normal heating, a method of heating with a microwave is also effective).

In the present invention, the above platinum complexes may be used alone or in combination of two or more.
The content of the compound represented by the general formula (C-1) in the light emitting layer of the present invention is preferably 1 to 30% by mass, more preferably 3 to 25% by mass in the light emitting layer, More preferably, it is 20 mass%.

[3-2] Pyrene Derivatives As the pyrene derivatives, conventionally known pyrene derivatives can be used, but compounds represented by the following general formula (P-1) are preferably used.

(In the formula, R _P ^{1 to} R _P ⁶ each independently represent a hydrogen atom, an aromatic hydrocarbon group which may have a substituent, an alkenyl group which may have a substituent, or a substituent. Alkynyl group which may have, alkyl group which may have substituent, silyl group which may have substituent, heterocyclic group which may have substituent, and substituent An arylamino group which may be substituted, and at least one of R _P ^{1 to} R _P ⁶ is a substituent other than a hydrogen atom.)

_<R ^P 1 ~R ^P 6>
(Types of substituents R _P ^{1 to} R _P ⁶ )
R _P ^{1 to} R _P ⁶ may each independently have a hydrogen atom, an aromatic hydrocarbon group that may have a substituent, an alkenyl group that may have a substituent, or a substituent. Good alkynyl group, optionally substituted alkyl group, optionally substituted silyl group, optionally substituted heterocyclic group, optionally substituted Represents an arylamino group.
At least one of R _P ^{1 to} R _P ⁶ is a substituent other than a hydrogen atom.

When two or more of R _P ^{1 to} R _P ⁶ are substituents other than hydrogen atoms, the substituents other than a plurality of hydrogen atoms may be the same or different. It is preferable that they are the same in terms of ease of synthesis, and are preferably different in that the emission wavelength can be tuned.

Moreover, the substituent other than the hydrogen atom of R _P ^{1 to} R _P ⁶ may have an aromatic hydrocarbon group which may have a substituent or a substituent in that high luminous efficiency is obtained. A good silyl group is preferable, and an aromatic hydrocarbon group which may have a substituent is particularly preferable. In addition, in terms of obtaining light emission with a narrow half width, substituents other than the hydrogen atoms of R _P ^{1 to} R _P ⁶ may have an alkynyl group or a substituent that may have a substituent. An alkyl group is preferable, and in terms of obtaining a product having a long emission wavelength, the substituents other than the hydrogen atoms of R _P ^{1 to} R _P ⁶ have an alkenyl group and a substituent which may have a substituent. Preferred heterocyclic groups are preferred.

As the aromatic hydrocarbon group of R _P ^{1 to} R _P ⁶ , those having 6 to 16 carbon atoms are preferable, these are not limited to monocyclic groups at all, and condensed polycyclic hydrocarbon groups and ring condensed hydrocarbon groups It may be. Specific examples include monocyclic groups such as phenyl groups, condensed polycyclic hydrocarbon groups such as biphenyl groups, phenanthryl groups, naphthyl groups, anthryl groups, and fluorenyl groups, and ring condensed hydrocarbon groups such as biphenyl groups.
The alkenyl group preferably has 2 to 20 carbon atoms, and specific examples include a styryl group and a diphenylvinyl group.
As the alkynyl group, those having 2 to 20 carbon atoms are preferable, and specific examples include a methylethynyl group, a phenylethynyl group, a trimethylsilylethynyl group, and the like.
As an alkyl group, a C3-C20 thing is preferable and i-propyl group, t-butyl group, a cyclohexyl group etc. are mentioned as a specific example.
The silyl group preferably has 3 to 20 carbon atoms, and specific examples include trimethylsilyl group, dimethylphenylsilyl group, dimethylbutylsilyl group, triisopropylsilyl group, and methyldibutylsilyl group.
As the heterocyclic group, those having 5 to 20 carbon atoms are preferable, and specific examples include pyridyl group, thienyl group, oxazole group, oxadiazole group, benzothienyl group, dibenzofuryl group, dibenzothienyl group, pyrazyl group, pyrimidyl. Group, pyrazoyl group, imidazolyl group, phenylcarbazoyl group and the like.
The arylamino group is preferably one having 6 to 30 carbon atoms, and specific examples include a diphenylamino group, a carbazoyl group, a phenylnaphthylamino group, and the like.

  These substituents may further have a substituent. Further, the substituents that may be included are aryl group, arylamino group, alkyl group, perfluoroalkyl group, halide group, carboxyl group, cyano group, alkoxyl group, aryloxy group, carbonyl group, oxycarbonyl group, carboxyl group An acid group, a heterocyclic group, etc. are mentioned. Preferably, an aryl group having 6 to 16 carbon atoms, an arylamino group having 12 to 30 carbon atoms, an alkyl group having 1 to 12 carbon atoms, a perfluoroalkyl group having 1 to 12 carbon atoms, a fluoride group, and 1 to 10 carbon atoms. An oxycarbonyl group, a cyano group, an alkoxy group having 1 to 10 carbon atoms, an aryloxy group having 6 to 16 carbon atoms, a carbonyl group having 2 to 16 carbon atoms, a heterocyclic group having 5 to 20 carbon atoms, and the like.

Further, among the substituents that may be included, examples of the aryl group having 6 to 16 carbon atoms include a phenyl group, a naphthyl group, and a phenanthryl group.
Examples of the arylamino group having 12 to 30 carbon atoms include a diphenylamino group, a carbazoyl group, and a phenylcarbazoyl group.
Examples of the alkyl group having 1 to 12 carbon atoms include a methyl group, an ethyl group, a butyl group, and a t-butyl group.
A trifluoromethyl group etc. are mentioned as an example of a C1-C12 perfluoroalkyl group.
Examples of the oxycarbonyl group having 1 to 10 carbon atoms include a methoxycarbonyl group and an ethoxycarbonyl group.
Examples of the alkoxy group having 1 to 10 carbon atoms include a methoxy group and an ethoxy group.
Examples of the aryloxy group having 6 to 16 carbon atoms include a phenyloxy group.
Examples of the carbonyl group having 2 to 16 carbon atoms include an acetyl group and a phenylcarbonyl group.
Examples of the heterocyclic group having 5 to 20 carbon atoms include pyridyl group, thienyl group, oxazole group, oxadiazole group, benzothienyl group, dibenzofuryl group, dibenzothienyl group, pyrazyl group, pyrimidyl group, pyrazoyl group, and imidazoyl. Group and the like.
Among the substituents that R _P ^{1 to} R _P ⁶ and R _P ^{1 to} R _P ^{6 described above} may have, an electron donating group such as an arylamino group and an alkoxy group, a thienyl group, and a benzothienyl group And the like contribute to the increase in the emission wavelength of the compound (P-1). Thus the substituent that may be _R ^P 1 _~R ^{P 6} and _R ^P 1 _~R ^{P 6} has, by selecting these substituents, can be obtained that exhibit a green light emission.

Of the compounds (P-1), particularly preferred are those having a structure represented by the following general formula (P-1a) or (P-1b) (the following general formula (P-1a) , (P-1b), R _P ¹ , R _P ³ , R _P ⁴ , R _P ⁶ have the same meanings as in general formula (P-1), and are represented by general formula (P-1a) below. The compound having the structure is referred to as “compound (P-1a)”, and the compound having the structure represented by the general formula (P-1b) may be referred to as “compound (P-1b)”.

  The pyrene derivative is more preferably a pyrene derivative exhibiting liquid crystallinity. Examples of the pyrene derivative exhibiting liquid crystallinity include a pyrene derivative represented by the following general formula (PI).

In the general formula (P-I), R _P means R _P ¹ — or R _P ¹ —CO—. p is the number of substituents and represents an integer of 1 to 5. Although all the compounds having these groups are not liquid crystalline, an appropriate group having liquid crystallinity can be selected and used based on known techniques. Examples of _RP ¹ include an alkyl group, an alkyl group in which a ring such as a phenylene group or a cyclohexylene group is combined, an oxygen group in which an oxygen atom is disposed between carbon and carbon of the alkyl group, and the like.

The R _{P, ^{specifically, R P 2 -, R P}} 2 -O-R P 3 -, R P 2 -O-Ph-CO-, R P 2 - (O-R P 3) nP - ^{_{O-Ph-CO-, R P}} 2 -O-Ph-CH = CH-CO-, CH 2 = CH-COO-R P 3 -O-Ph-CO- and the like. Here, R _P ² represents an alkyl group, R _P ³ represents an alkylene group, Ph represents a phenylene group which may have a substituent, and n _P represents-(O-R _P ³ )-. And represents an integer of 1 or more.

The number of carbon atoms of the alkyl group represented by R _P ² is preferably in the range of 1-20, more preferably in the range of 1-15, and even more preferably in the range of 3-10. The alkyl group represented by R _P ² may be linear or branched, but is preferably linear in terms of liquid crystallinity.
The number of carbon atoms of the alkylene group represented by R _P ³ is preferably in the range of 1-20, more preferably in the range of 1-15, and even more preferably in the range of 3-10.
Ph represents a phenylene group which may have a substituent group, includes as the substituent also be a halogen atom such as fluorine atom, an alkyl group, an alkoxy group, and the expression of the N _D phase From the viewpoint, an alkyl group is preferable. The number of carbon atoms of the alkyl group or alkoxy group as a substituent is preferably in the range of 1 to 20, more preferably in the range of 1 to 10, and still more preferably in the range of 1 to 6.
n _{P ^{is, - (O-R P 3}} ) - number of repetitions of the represents an integer of 1 or more. n _P is preferably an integer of from 1 to 10, more preferably an integer from 1 to 6, more preferably an integer of 1 to 3.

The R _P, in terms of _{solubility, R} ^{P 2} - is preferred.
p is the number of substituents, preferably an integer of 1 to 3, more preferably an integer of 1 or 2. The pyrene derivative represented by the general formula (PI) preferably has a substituent at least at the 4-position of the benzene ring from the viewpoint of imparting liquid crystallinity and solubility.

  The pyrene derivative represented by the general formula (P-I) is preferably a pyrene derivative represented by the following general formula (P-II) from the viewpoint of high solubility.

In the general formula _{(P-II), R} P has the same meaning as _{R P} in the general formula (P-I).

Specific examples and preferred ranges of _{R P} in the general formula (P-II) are the same as those in general formula (P-I).

  Although the specific example of the pyrene derivative which can be used by this invention is shown, this invention is not limited to these.

  The content of the pyrene derivative represented by the general formula (PI) in the light emitting layer of the present invention is preferably 0.5 to 30% by mass in the light emitting layer, and more preferably 1 to 20% by mass. More preferably, the content is 1.5 to 10% by mass.

[4] Solvent When the layer contained in the electroluminescent device of the present invention is formed by a wet method, it can be used as a solvent that can be used to prepare a composition by dissolving each component contained in the layer. Examples include known organic solvents such as aromatic hydrocarbon solvents, alcohol solvents, ketone solvents, aliphatic hydrocarbon solvents, amide solvents, and the like.

  Examples of the aromatic hydrocarbon solvent include benzene, toluene, xylene, trimethylbenzene, tetramethylbenzene, cumeneethylbenzene, methylpropylbenzene, methylisopropylbenzene, and the like, and toluene, xylene, cumene, and trimethylbenzene are more preferable. preferable. The relative dielectric constant of the aromatic hydrocarbon solvent is usually 3 or less.

Examples of the alcohol solvent include methanol, ethanol, butanol, benzyl alcohol, cyclohexanol, and the like, butanol, benzyl alcohol, and cyclohexanol are more preferable. The relative dielectric constant of the alcohol solvent is usually 10-40.
As ketone solvents, 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 4-heptanone, 1-hexanone, 2-hexanone, 2-butanone, diisobutylketone, cyclohexanone, methylcyclohexanone, phenylacetone , Methyl ethyl ketone, methyl isobutyl ketone, acetyl acetone, acetonyl acetone, ionone, diacetonyl alcohol, acetyl carbinol, acetophenone, methyl naphthyl ketone, isophorone, propylene carbonate, etc., 2-butanone, methyl isobutyl ketone, propylene carbonate preferable. The relative permittivity of the ketone solvent is usually 10 to 90.
Examples of the aliphatic hydrocarbon solvent include pentane, hexane, octane, decane and the like, and octane and decane are preferable. The relative dielectric constant of the aliphatic hydrocarbon solvent is usually 1.5 to 2.0.
Examples of amide solvents include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, 1,3-dimethyl-2-imidazolidinone and the like. N-methyl-2-pyrrolidone and 1,3-dimethyl-2-imidazolidinone are preferred. The relative dielectric constant of the amide solvent is usually 30-40.
In the present invention, the above solvents may be used alone or in combination of two or more.

[5] Configuration of Organic Electroluminescent Device The configuration of the organic electroluminescent device in the present invention will be described in detail.
The organic electroluminescent device of the present invention is an organic electroluminescent device having a pair of electrodes composed of an anode and a cathode, a light emitting layer having a triphenylene derivative exhibiting liquid crystallinity, and an electron transport layer between the pair of electrodes. Thus, a triphenylene derivative capable of vapor deposition is provided as a buffer layer between the light emitting layer and the electron transport layer.
A pair of electrodes consisting of the anode and the cathode is generally formed on a substrate. In view of the properties of the light emitting element, at least one of the anode and the cathode is preferably transparent or translucent.
FIG. 1 shows an example of the configuration of an organic electroluminescent device according to the present invention.
In the organic electroluminescent element 10 according to the present invention shown in FIG. 1, a light emitting layer 6 is sandwiched between an anode 3 and a cathode 9 on a substrate 2. Specifically, a hole injection layer 4, a hole transport layer 5, a light emitting layer 6, a buffer layer 11, an electron transport layer 7, and an electron injection layer 8 are laminated in this order between the anode 3 and the cathode 9. Yes.

<Structure of organic layer>
The layer structure of the organic layer is not particularly limited as long as it has a buffer layer between the light emitting layer and the electron transport layer, and can be appropriately selected according to the use and purpose of the organic electroluminescent element. It is preferably formed on the transparent electrode or on the back electrode. In this case, the organic layer is formed on the front surface or one surface of the transparent electrode or the back electrode.
There is no restriction | limiting in particular about the shape of a organic layer, a magnitude | size, thickness, etc., According to the objective, it can select suitably.

Specific examples of the layer configuration include the following, but the present invention is not limited to these configurations.
Anode / hole transport layer / light emitting layer / buffer layer / electron transport layer / electron injection layer / cathode,
Anode / hole transport layer / light emitting layer / buffer layer / block layer / electron transport layer / electron injection layer / cathode,
Anode / hole injection layer / hole transport layer / light emitting layer / buffer layer / electron transport layer / electron injection layer / cathode.
Anode / hole injection layer / hole transport layer / light emitting layer / buffer layer / block layer / electron transport layer / electron injection layer / cathode.
Anode / hole injection layer / hole transport layer / exciton block layer / light emitting layer / buffer layer / electron transport layer / electron injection layer / cathode.
The substrate, cathode, and anode of the organic electroluminescence device are described in detail in, for example, Japanese Patent Application Laid-Open No. 2008-270736, and the matters described in the publication can be applied to the present invention.

<Board>
The substrate used in the present invention is preferably a substrate that does not scatter or attenuate light emitted from the organic layer. 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.

<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.

<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.
In the present invention, the cathode is preferably formed by sputtering. Compared to the case where the cathode is deposited by resistance heating vacuum deposition, the cathode is deposited by non-heating sputtering to reduce thermal damage to the light-emitting layer that has liquid crystal properties (that is, the liquid crystal phase). As a result, disturbance of the liquid crystal phase can be reduced, which is preferable.
In the present invention, the cathode is preferably aluminum or an alloy of aluminum and lithium (preferably in a weight ratio of 50:50 to 99: 1) from the viewpoint of electron injecting property.

<Organic layer>
The organic layer in the present invention will be described.

[Formation of organic layer]
In the organic electroluminescent device of the present invention, each organic layer is applied by a solution such as a dry film forming method such as a vacuum deposition method or a sputtering method, a transfer method, a printing method, a spin coating method, a bar coating method, an ink jet method, or a spray method. It can be suitably formed by any process (wet method).

In the organic electroluminescent device of the present invention, any one of the organic layers is preferably formed by a wet method, and at least the light-emitting layer is preferably formed by a wet method. In addition to the light-emitting layer, a hole injection layer is formed. It is more preferable that at least one of the hole transport layer and the hole transport layer is formed by a wet method, and it is more preferable that both of them are formed by a wet method. On the other hand, at least the buffer layer (adjacent layer) is preferably formed by a dry method, and at least one of the electron transport layer and the electron injection layer is more preferably formed by a dry method, both of which are formed by a dry method. More preferably, a film is formed. Here, as a dry method, a vacuum deposition method is preferable.
Further, other layers than the above can be formed by appropriately selecting a dry method or a wet method. When the wet method is used, the organic layer can be easily increased in area, and a light-emitting element having high luminance and excellent light emission efficiency can be obtained efficiently at low cost, which is preferable. Vacuum deposition, sputtering, etc. can be used as dry methods, and dipping, spin coating, dip coating, casting, die coating, roll coating, bar coating, gravure coating, and spray coating as wet methods. Method, ink jet method and the like can be used. These film forming methods can be appropriately selected according to the material of the organic layer. When the film is formed by a wet method, it may be dried after the film is formed. Drying is performed by selecting conditions such as temperature and pressure so that the coating layer is not damaged.

The coating solution used in the wet film-forming method (coating process) usually comprises an organic layer material and a solvent for dissolving or dispersing it. A solvent is not specifically limited, What is necessary is just to select according to the material used for an organic layer. Specific examples of the solvent include halogen solvents (chloroform, carbon tetrachloride, dichloromethane, 1,2-dichloroethane, chlorobenzene, etc.), ketone solvents (acetone, methyl ethyl ketone, diethyl ketone, n-propyl methyl ketone, 2-butanone, Cyclohexanone, etc.), aromatic solvents (benzene, toluene, xylene, etc.), ester solvents (ethyl acetate, n-propyl acetate, n-butyl acetate, methyl propionate, ethyl propionate, γ-butyrolactone, diethyl carbonate, etc.) , Ether solvents (tetrahydrofuran, dioxane, etc.), amide solvents (dimethylformamide, dimethylacetamide, etc.), dimethyl sulfoxide, alcohol solvents (methanol, propanol, butanol, etc.), water and the like.
The solid content with respect to the solvent in the coating solution is not particularly limited, and the viscosity of the coating solution can be arbitrarily selected according to the film forming method.

[Light emitting layer]
In the organic electroluminescent element of the present invention, the light emitting layer contains a light emitting material. Examples of the light emitting material include those described in the above [3] Light emitting material. A luminescent material may be used independently or may use 2 or more types together.
Although content in particular of the luminescent material in a light emitting layer is not restrict | limited, For example, it is 0.1-70 mass%, and it is preferable that it is 1-50 mass%. If the content of the light emitting material is less than 0.1% by mass or exceeds 70% by mass, the effect may not be sufficiently exhibited.

  In the present invention, the light emitting layer may contain a host compound other than the triphenylene derivative exhibiting liquid crystallinity, if necessary, as long as liquid crystallinity is not impaired.

  The host compound is a compound that causes energy transfer from the excited state to the phosphorescent compound, and as a result, causes the phosphorescent compound to emit light. Specific examples include carbazole derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, styrylanthracene derivatives. , Fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic tertiary amine compounds, styrylamine compounds, aromatic dimethylidene compounds, porphyrin compounds, anthraquinodimethane derivatives, anthrone derivatives, diphenylquinone derivatives, thiopyran dioxide oxide Derivatives, carbodiimide derivatives, fluorenylidenemethane derivatives, distyrylpyrazine derivatives, and heterocyclic tetra Rubonic acid anhydride, phthalocyanine derivative, metal complex of 8-quinolinol derivative, metal phthalocyanine, metal complex having benzoxazole or benzothiazole as a ligand, polysilane compound, poly (N-vinylcarbazole) derivative, aniline copolymer , Conductive polymers such as thiophene oligomers and polythiophenes, polythiophene derivatives, polyphenylene derivatives, polyphenylene vinylene derivatives, polyfluorene derivatives, and the like. A host compound may be used individually by 1 type, or may use 2 or more types together.

When the light emitting layer of the present invention is formed by a wet method, it is also preferable from the viewpoint of liquid crystallinity to form a light emitting layer by curing by a curing reaction after application of the light emitting layer forming coating solution.
The curing reaction is not particularly limited, and examples thereof include photopolymerization and thermal polymerization, and a photopolymerization reaction is preferable.
The light emitting layer forming coating solution preferably contains a polyfunctional polymerizable compound, such as neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di ( (Meth) acrylate, 1,10-decanediol di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, modified trimethylolpropane triacrylate, DPHA (dipentaerythritol hexaacrylate) And the like, and trimethylolpropane triacrylate and modified trimethylolpropane triacrylate are preferable. The content of the polymerizable compound in the light emitting layer forming coating solution is preferably 1 to 30% by mass, more preferably 3 to 20% by mass, and further preferably 5 to 15% by mass based on the total solid content. %.
In order to smoothly advance the curing reaction, the light emitting layer forming coating solution preferably contains a photopolymerization initiator. Specifically, IRGACURE 907, IRGACURE 651, IRGACURE 184, IRGACURE 500, IRGACURE 2959, IRGACURE. 127, IRGACURE 754, IRGACURE 369, IRGACURE 379, IRGACURE 379EG, IRGACURE 1300, IRGACURE OXE01, IRGACUR OXE02, DAROCURE 1173, DAROCURE MBF, and the like, IR7. The content of the photopolymerization initiator in the light emitting layer forming coating solution is preferably 0.1 to 10% by mass, more preferably 0.5 to 5% by mass, based on the solid content having a polymerizable group. Yes, more preferably 1 to 3% by mass.

  The thickness of the light emitting layer is preferably 10 to 200 nm, and more preferably 20 to 80 nm. When the thickness is 200 nm or less, an increase in driving voltage is suppressed, and when the thickness is 10 nm or more, a short circuit of the light emitting element is suppressed.

(Hole injection layer, hole transport layer)
The organic electroluminescent element of the present invention may have a hole injection layer and a 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.
The hole injection layer and the hole transport layer are described in detail, for example, in JP-A-2008-270736 and JP-A-2007-266458, and the matters described in these publications can be applied to the present invention.

(Electron injection layer, electron transport layer)
The organic electroluminescent element of the present invention preferably has an electron injection layer and further has an 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. The electron injection material and the electron transport material used for these layers may be a low molecular compound or a high molecular compound.
For the electron injection layer, any one of known materials such as lithium fluoride (LiF), strontium (Sr) cesium fluoride (CsF), cesium bromide (CsBr) mono (8-quinolinolato) lithium complex (Liq) is vacuumed. It is preferably formed by vapor deposition by a vapor deposition method, and among these, lithium fluoride (LiF) is more preferable.
The thickness of the electron injection layer is preferably from 0.1 nm to 10 nm, more preferably from 0.5 nm to 50 nm, and even more preferably from 0.5 nm to 1.5 nm.
Electron transport layers are known, such as BAlq (Bis- (2-methyl-8-quinolinolato) -4- (phenyl-phenolate) -aluminum- (III)), Alq ₃ (Tris (8-quinolinolato) aluminum) and BCP. It is preferable that any one of these materials is deposited by vacuum deposition, and among these, BAlq and Alq ₃ are more preferable.
The thickness of the electron transport layer is preferably 1 nm to 100 nm, more preferably 10 nm to 70 nm, and even more preferably 30 nm to 50 nm.
The electron injection layer and the electron transport layer are described in detail in, for example, JP-A-2008-270736 and JP-A-2007-266458, and the matters described in these publications can also be applied to the present invention.

(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.
As an example of the organic compound constituting the hole blocking layer, aluminum (III) bis (2-methyl-8-quinolinato) 4-phenylphenolate (Aluminum (III) bis (2-methyl-8-quinolinato) 4- aluminum complexes such as phenylphenolate (abbreviated as BAlq), triazole derivatives, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (2,9-Dimethyl-4,7-diphenyl-1,10-) phenanthroline derivatives such as phenanthroline (abbreviated as BCP), triphenylene derivatives, carbazole derivatives, 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.

(Electronic block layer)
The electron blocking layer is a layer having a function of preventing electrons transported from the cathode side to the light emitting layer from passing through to the anode side. In the present invention, an electron blocking layer can be provided as an organic layer adjacent to the light emitting layer on the anode side.
As an example of the organic compound constituting the electron blocking layer, for example, those mentioned as the hole transport material described above can be applied.
The thickness of the electron blocking layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and even more preferably 10 nm to 100 nm.
The electron blocking 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.

(Description of exciton block layer)
The exciton blocking layer is a layer formed at one or both of the interface between the light emitting layer and the hole transport layer, or the interface between the light emitting layer and the electron transport layer, and the excitons generated in the light emitting layer are holes. It is a layer that diffuses into the transport layer and the electron transport layer and prevents deactivation without emitting light. The exciton blocking layer is preferably made of a carbazole derivative.

[Other organic layers]
The organic electroluminescent device of the present invention has a protective layer described in JP-A-7-85974, 7-192866, 8-22891, 10-275682, 10-106746, etc. Also good. The protective layer is formed on the uppermost surface of the light emitting element. Here, when the base material, the transparent electrode, the organic layer, and the back electrode are laminated in this order, the top surface refers to the outer surface of the back electrode, and the base material, the back electrode, the organic layer, and the transparent electrode are laminated in this order. In some cases, it refers to the outer surface of the transparent electrode. The shape, size, thickness and the like of the protective layer are not particularly limited. The material for forming the protective layer is not particularly limited as long as it has a function of suppressing intrusion or permeation of a light-emitting element such as moisture or oxygen into the element. Silicon, germanium oxide, germanium dioxide or the like can be used.

  The method for forming the protective layer is not particularly limited. For example, vacuum deposition, sputtering, reactive sputtering, molecular sensing epitaxy, cluster ion beam, ion plating, plasma polymerization, plasma CVD, laser CVD Thermal CVD method, coating method, etc. can be applied.

[Electron affinity]
In the organic electroluminescent device of the present invention, the electron affinity (Ea1) of the triphenylene derivative exhibiting liquid crystallinity of the light emitting layer, the electron affinity (Ea2) of the triphenylene derivative capable of vapor deposition of the buffer layer, and the electron transport layer The electron affinity (Ea3) of the constituting compound is
Ea1 ≦ Ea2 <Ea3
It is preferable that electrons are efficiently injected from the electron transport layer to the light emitting layer.

The electron affinity can be measured by the difference in energy gap from the ionization potential.
The electron affinity (Ea1, Ea2) of the triphenylene derivative is generally 1.52.5 eV.
The electron affinity (Ea1) of the triphenylene derivative exhibiting liquid crystallinity of the light emitting layer, the electron affinity (Ea2) of the triphenylene derivative capable of vapor deposition of the buffer layer, and the electron affinity (Ea3) of the compound constituting the electron transport layer The preferred relationship is
0.8 * {(Ea3-Ea1) / 2} + Ea3 ≧ Ea2 ≧ 0.2 * {(Ea3-Ea1) / 2} + Ea3
And a more preferable relationship is
0.6 * {(Ea3−Ea1) / 2} + Ea3 ≧ Ea2 ≧ 0.4 * {(Ea3−Ea1) / 2} + Ea3
And an even more preferred relationship is
(Ea3-Ea1) / 2 + Ea3 = Ea2
It is.

[Sealing]
The organic electroluminescent element is preferably provided with a sealing layer for preventing moisture and oxygen from entering. As a material for forming the sealing layer, a copolymer of tetrafluoroethylene and at least one comonomer, a fluorinated copolymer having a cyclic structure in the copolymer main chain, polyethylene, polypropylene, polymethyl methacrylate, polyimide, Polyurea, polytetrafluoroethylene, polychlorotrifluoroethylene, polydichlorodifluoroethylene, chlorotrifluoroethylene or a copolymer of dichlorodifluoroethylene and another comonomer, a water-absorbing substance having a water absorption of 1% or more, a water absorption of 0. 1% or less moisture-proof material, metal (In, Sn, Pb, Au, Cu, Ag, Al, Tl, Ni, etc.), metal oxide (MgO, SiO, SiO ₂ , Al ₂ O ₃ , GeO, NiO, _{CaO, BaO, Fe 2 O 3} , Y 2 O 3, TiO 2 , etc.), metal fluorides (M _{F 2, LiF, AlF 3,} CaF 2 , etc.), liquid fluorinated carbon (perfluoroalkane, perfluoro amines, perfluoroether, etc.), the liquid fluorinated carbon as dispersed adsorbent moisture or oxygen, etc. Can be used.

  The organic electroluminescence device of the present invention emits light by applying a direct current (which may include an alternating current component as necessary) voltage (usually 2 to 15 volts) or a direct current between the anode and the cathode. Can be obtained.

  The driving method of the organic electroluminescence device of the present invention is described in JP-A-2-148687, JP-A-6-301355, JP-A-5-29080, JP-A-7-134558, JP-A-8-234658, and JP-A-8-2441047. The driving method described in each publication, Japanese Patent No. 2784615, US Pat. Nos. 5,828,429, 6023308, and the like can be applied.

  The present invention will be described more specifically with reference to the following examples. The materials, reagents, substance amounts and ratios, operations, and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention is not limited to the following specific examples.

(Example 1: Pt complex)
<Production of organic electroluminescence device>
After depositing ITO (Indium Tin Oxide) as a positive electrode on a 0.7 mm thick, 25 mm square glass substrate to a thickness of 150 nm, etching and cleaning were performed. The substrate on which the ITO film was formed was placed in a cleaning container and subjected to ultrasonic cleaning in 2-propanol, and then subjected to UV-ozone treatment for 30 minutes. The following layers were formed on this glass substrate.
The spin coating, drying, and annealing were performed in a glove box (dew point -60 ° C., oxygen concentration 1 ppm).
Next, on the anode (ITO), PTPDES represented by the following structural formula (Kemipro Kasei Co., Ltd., weight average molecular weight = 13000. N represents the number of repetitions of the structure in parentheses and is an integer.) 2 parts by mass Is spin-coated with a hole injection layer coating solution dissolved or dispersed in 98 parts by mass of cyclohexanone for electronics industry (manufactured by Kanto Chemical), dried at 120 ° C. for 10 minutes, and annealed at 160 ° C. for 60 minutes. A hole injection layer having a thickness of 40 nm was formed.

Next, 4 parts by mass of a hole transport material HTL-1 (HTL-1 described in US Patent US2008 / 0220265) having the following structure is dissolved in 996 parts by mass of 2-butanone (manufactured by Kanto Chemical) for electronic industry, A hole transport layer coating solution was prepared.
This hole transport layer coating solution was spin coated on the hole injection layer and dried at 150 ° C. for 30 minutes to form a 10 nm thick hole transport layer.

Next, as the light emitting layer, 16.3 parts by mass of the host liquid crystal compound H-1 having the following structure, 1.7 parts by mass of the modified trimethylolpropane triacrylate represented by the following structural formula, and the following structural formula are used. 0.5 parts by mass of a photopolymerization initiator (IRGACURE 907) and 2 parts by mass of phosphorescent material E-1 having the following structure were dissolved in 979.5 parts by mass of 2-butanone (manufactured by Kanto Chemical) for electronic industry. Alternatively, dispersed, molecular sieve (trade name: Molecular sieve 3A 1/16, manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the light-emitting layer was prepared by filtration using a syringe filter with a pore size of 0.22 μm in a glove box. The solution is spin-coated in a glove box, dried at 80 ° C. for 10 minutes, and then UV chamber: ELC-500 (ELCTRO-LITE CORPORATION) ) The UV exposure for 10 minutes using a by a 30 min annealing at 80 ° C., to form a luminescent layer having a thickness of 40nm on the hole transport layer.
In addition, when the phase transition temperature of liquid crystal compound H-1 was measured, it was determined that the phase transition from the Nd phase to the isotropic phase at a temperature of 215 ° C. ) Was confirmed from the measurement using.

  As an adjacent layer, a triphenylene compound AD-1 having the following structure was deposited by a vacuum deposition method to form a 5 nm thick layer on the light emitting layer.

  Next, BAlq (Bis- (2-methyl-8-quinolinolato) -4- (phenyl-phenolate) -aluminum- (III)) was deposited by a vacuum deposition method, and an electron transport layer having a thickness of 35 nm was formed as an adjacent layer. Formed on top.

Next, lithium fluoride (LiF) was deposited on the electron transport layer to form an electron injection layer having a thickness of 1 nm.
Next, metal aluminum was vapor-deposited on the electron injection layer to form a cathode having a thickness of 70 nm.
The produced laminate was put in a glove box substituted with argon gas, and sealed using a stainless steel sealing can and an ultraviolet curable adhesive (XNR5516HV, manufactured by Nagase Ciba Co., Ltd.).

(Comparative Example 1)
An organic electroluminescent element was produced in the same manner as in Example 1 except that the triphenylene compound AD-1 as the adjacent layer was not evaporated and BAlq as the electron transport layer was evaporated to a thickness of 40 nm.

(Example 2: Pyrene derivative)
An organic electroluminescent element was produced in the same manner as in Example 1 except that the light emitting layer was formed as described below.
As a light emitting layer, 17 parts by mass of the host liquid crystal compound H-1, 2 parts by mass of the modified trimethylolpropane triacrylate, 0.5 parts by mass of the photopolymerization initiator, and a fluorescent light emitting material E having the following structure -2 (Journal of Materials Chemistry, 2007, 17, 1392-1398) is dissolved or dispersed in 979.5 parts by mass of 2-butanone (manufactured by Kanto Chemical) for electronic industry, and molecular sieve ( Product name: Molecular sieve 3A 1/16, manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the light emitting layer coating solution prepared by filtering using a syringe filter with a pore size of 0.22 μm in the glove box was used in the glove box. After spin coating and drying at 80 ° C. for 10 minutes, UV chamber: ELC-500 (ELCTRO-LITE UV exposure was carried out for 10 minutes using CORPORATION, and an annealing treatment was carried out at 80 ° C. for 30 minutes to form a 40 nm thick light emitting layer on the hole transport layer.

(Comparative Example 2)
An organic electroluminescent element was produced in the same manner as in Example 2 except that the triphenylene compound AD-1 as the adjacent layer was not evaporated and BAlq as the electron transport layer was evaporated to a thickness of 40 nm.

Example 3
The triphenylene compound AD-1 as the adjacent layers is changed to triphenylene compounds AD-2 having the following structure, and except for changing the electron-transporting layer Alq ₃ was fabricated an organic electroluminescence device in the same manner as in Example 1.

(Comparative Example 3)
Without depositing triphenylene compound AD-2 as adjacent layers, and except for depositing Alq ₃ to a thickness 40nm as an electron transport layer, to produce an organic electroluminescence device in the same manner as in Example 3.

(Comparative Example 4)
An organic electroluminescent element was produced in the same manner as in Example 1 except that BCP (Bathocuproine, manufactured by Aldrich) having the following structure was deposited instead of the triphenylene compound AD-1 as an adjacent layer.

Example 4
The host material used for the light emitting layer is changed to a host liquid crystal compound H-2 having the following structure (compound described in JP-A-10-321371), and copper phthalocyanine is used as a buffer layer in place of vapor deposition of metallic aluminum as a cathode. (CuPc) was deposited to a thickness of 20 nm by a vacuum deposition method, and then an organic layer was formed in the same manner as in Example 1 except that an Al: Li alloy (mass ratio 97: 3) was formed by a sputtering method. An electroluminescent element was produced.

<Element evaluation>
(A) Element performance Using a source measure unit 2400 manufactured by Toyo Technica, a direct current voltage was applied to each element to emit light, and the luminance was measured using a luminance meter BM-8 manufactured by Topcon Corporation.
The device performance was evaluated in two stages, ◯ and × as described below.
○: Luminance with a luminance of 20 cd / m ² or more ×: Luminance with a luminance of less than 20 cd / m ² (b) Durability The direct current with a current density of 0.1 mA / cm ² is adjusted at room temperature, and the luminance is halved from the initial luminance. The time required to do this was used as an index of durability.
Durability was evaluated in two stages, ◯ and × as described below.
○: 1 hour or more ×: less than 1 hour

(Comparative Example 5)
A light emitting layer coating solution was prepared in the same manner as in Example 1 except that the triphenylene compound AD-1 was used as the light emitting layer host instead of the host liquid crystal compound H-1, and the solvent was changed to tetrahydrofuran. Although this was coated on the hole transport layer in the same manner as in Example 1, it crystallized during drying, and a light emitting layer could not be formed.

  The results are shown in Table 1. Table 2 shows the electron affinity of the materials used in the examples. The electron affinity was measured by the method described below.

(Method for measuring electron affinity)
(1) Measurement of ionization potential An organic substance was formed on a glass substrate so as to have a thickness of 50 nm. The ionization potential of this membrane was measured with an ultraviolet photoelectron analyzer AC-2 manufactured by Riken Keiki under normal temperature and normal pressure.
(2) Electron affinity measurement The ultraviolet-visible absorption spectrum of the film used for ionization potential measurement was measured, and the excitation energy was determined from the energy at the long wavelength end of the absorption spectrum. The electron affinity was calculated from the excitation energy and the value of the ionization potential.

  As is clear from the results in Table 1 above, the elements of Examples 1 to 4 each having a triphenylene derivative that can be deposited as a buffer layer between the light-emitting layer having the triphenylene derivative exhibiting liquid crystallinity and the electron transporting layer, It turns out that luminous efficiency and durability improved compared with the element of Comparative Examples 1-5 which does not have such a buffer layer. Further, in the element of Comparative Example 4, the relationship between Ea1, Ea2, and Ea3 did not satisfy the relationship of Ea1 ≦ Ea2 <Ea3, so that the luminous efficiency and durability were low.

2 ... substrate 3 ... anode 4 ... hole injection layer 5 ... hole transport layer 6 ... light emitting layer 7 ... electron transport layer 8 ... electron injection layer 9 ... Cathode 10 ... Organic electroluminescence device 11 ... Buffer layer (adjacent layer)

Claims (9)

An organic electroluminescent device comprising a pair of electrodes composed of an anode and a cathode, a light emitting layer having a triphenylene derivative exhibiting liquid crystallinity, and an electron transport layer between the pair of electrodes,
Between the electron transport layer and the light emitting layer, and have a triphenylene derivative capable deposited as a buffer layer,
The triphenylene derivative exhibiting liquid crystallinity is a compound represented by the following general formula (T-1),
The triphenylene derivative capable of vapor deposition is one of a compound having a structural unit represented by the following general formula (1) and a compound represented by the following general formula (3). Light emitting element.
(In the formula, R _T represents R _T ^2- , R _T ² -O-, R _T ² -O-R _T ^3- , R _T ² -O-R _T ³ -O-, and R _T ² -O-. Ph—COO—, R _T ² — (O—R _T ³ ) _nT —O—Ph—COO—, R _T ² —O—Ph—CH═CH—COO—, or CH ₂ = CH—COO—R _T ³ represents -O-Ph-COO-, wherein R _T ² represents an alkyl group which may have a polymerizable group, R _T ³ represents an alkylene group, and Ph has a substituent. Represents a phenylene group which may be substituted, and n _T is a repeating number of — (O—R _T ³ ) — and represents an integer of 1 or more.)
^(Wherein, R 1, ^{R 2} and ^{R 3} represents a substituent. These may be different from one another identical .N1, n2 and n3 each independently represents an integer of 0 to 4 .)
(In the formula, Ar represents a substituted or unsubstituted aryl group. Ar may be the same or different.) The electron affinity (Ea1) of the triphenylene derivative exhibiting liquid crystallinity of the light emitting layer, the electron affinity (Ea2) of the triphenylene derivative capable of vapor deposition of the buffer layer, and the electron affinity (Ea3) of the compound constituting the electron transport layer But,
Ea1 ≦ Ea2 <Ea3
The organic electroluminescent element according to claim 1, wherein   The organic electroluminescent element according to claim 1, wherein the light emitting layer has a platinum complex.   The organic electroluminescent element according to claim 1, wherein the light emitting layer has a pyrene derivative. The triphenylene derivative capable of vapor deposition of the buffer layer is a compound having a structural unit represented by the general formula (1), and the compound is represented by the following general formula (2). The organic electroluminescent element of any one.
(Wherein R ⁴ , R ⁵ , R ⁶ And R ⁷ Represents a substituent. These may be the same as or different from each other. n4 and n5 each independently represents an integer of 0 to 4. ) The organic electroluminescent element according to claim 1, wherein the light emitting layer is formed by a wet method. The organic electroluminescent element according to claim 1, wherein the buffer layer is formed by a vacuum deposition method. The organic electroluminescent element according to claim 1, wherein the cathode is formed by a sputtering method. The organic electroluminescent element according to claim 8, wherein the cathode is an alloy of aluminum and lithium.