JP5353069B2 - Triphenylene compound, organic electroluminescence device containing triphenylene compound, and organic EL display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compound useful for an organic layer of an organic electroluminescent element, formed into a film by a wet process, having excellent solubility in a solvent and heat resistance, and providing the organic electroluminescent element driven by a low drive voltage and having sufficient life even being formed by the wet film-forming process. <P>SOLUTION: The triphenylene-based compound is obtained, for example, by the chemical reaction formula (A). <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a triphenylene compound useful for an organic electroluminescence device and the like.

  In recent years, as a thin film type electroluminescent element, an organic electroluminescent element using an organic thin film has been developed instead of using an inorganic material. An organic electroluminescent element usually has a hole injection layer, a hole transport layer, an organic light emitting layer, an electron transport layer, and the like between an anode and a cathode, and materials suitable for these layers are being developed. Furthermore, the organic electroluminescent elements are also being developed for red, green and blue.

However, the blue light emitting element is not satisfactory in terms of efficiency, life, and heat resistance, and there is a problem that application to a full color display is limited.
In addition, as a method for forming each layer of the organic electroluminescent element, there are a vacuum deposition method and a wet film formation method. The vacuum deposition method has a problem in terms of yield when manufacturing a medium or large full color panel for a television or a monitor. Therefore, the wet film-forming method is suitable for these large area applications.

In order to form each layer of the organic electroluminescent element by the above-described wet film formation method, it has been desired that the material forming each layer is dissolved in a solvent and has high performance as an element even after the wet film formation. However, many materials that have been used in the conventionally developed vapor deposition method are not suitable for the wet film formation method.
For example, Patent Document 1 discloses an element manufactured by a wet film formation method using a material represented by the following formula.

  Patent Document 2 discloses an element manufactured by a wet film forming method using a material represented by the following formula.

However, these materials do not satisfy the physical properties required in the process of wet film formation, such as solubility in solvents and heat resistance. In addition, even when used in an organic electroluminescent device, there are problems such as a high driving voltage and insufficient life.
International Publication No. 2006/070712 Pamphlet JP 2004-224766 A

  An object of the present invention is to provide a compound having an emission wavelength close to pure blue suitable for an organic electroluminescence device. In addition, in an organic electroluminescent device having an organic layer formed by a wet film formation method, a driving voltage is low, a sufficient life is provided, and a material for an organic electroluminescent device for providing the device is provided. This is the issue.

As a result of intensive studies by the present inventors, it has been found that the above problems can be solved by using a triphenylene compound represented by the following formula (1), and the present invention has been achieved.
That is, the present invention relates to a triphenylene compound represented by the following formula (1), a composition for an organic electroluminescence device containing the compound and a solvent, an organic electroluminescence device having an organic layer containing the compound, and an organic EL. Lies on the display.

(In the formula (1), T represents an n-valent group derived from a triphenylene ring which may have a substituent. X represents an aromatic hydrocarbon group or a substituent which may have a substituent. Represents an aromatic heterocyclic group that may be present, m represents an integer of 1 or more, n represents an integer of 2 or more, and Ar ¹ and Ar ² each independently have a substituent. Represents an aromatic hydrocarbon group which may have an aromatic hydrocarbon group or a substituent.

When m or n is 2 or more, a plurality of Ar ¹ , Ar ² , and X contained in one molecule may be the same or different from each other independently. )

The compound of the present invention has an emission wavelength close to pure blue suitable for an organic electroluminescence device.
In addition, when an organic electroluminescent device is produced using the compound of the present invention, an organic electroluminescent device having a low driving voltage and a sufficient lifetime can be obtained.

Embodiments of the present invention will be described in detail below. However, the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the invention.
The present invention resides in a triphenylene compound characterized by being represented by the following formula (1).

(In the formula (1), T represents an n-valent group derived from a triphenylene ring which may have a substituent. X represents an aromatic hydrocarbon group or a substituent which may have a substituent. Represents an aromatic heterocyclic group that may be present, m represents an integer of 1 or more, n represents an integer of 2 or more, and Ar ¹ and Ar ² each independently have a substituent. Represents an aromatic hydrocarbon group which may have an aromatic hydrocarbon group or a substituent.

When m or n is 2 or more, a plurality of Ar ¹ , Ar ² , and X contained in one molecule may be the same or different from each other independently. )
<Formula (1)>
(About T)
T represents an n-valent group derived from a triphenylene ring which may have a substituent.

  Examples of the substituent that T may have include an alkyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, an alkoxy group, a (hetero) aryloxy group, an alkylthio group, a (hetero) arylthio group, a cyano group, and a dialkylamino group. And organic groups such as an alkyl reelamino group and a diarylamino group. The alkyl group and the aromatic hydrocarbon group are preferable from the viewpoint of the stability of the compound, and the aromatic hydrocarbon group is particularly preferable. The above (hetero) aryl refers to both aryl and heteroaryl.

  The alkyl group preferably has 1 to 20 carbon atoms. For example, methyl group, ethyl group, propyl group, iso-propyl group, butyl group, iso-butyl group, sec-butyl group, tert-butyl group, hexyl group, octyl group. Group, cyclohexyl group, decyl group, octadecyl group and the like. A methyl group, an ethyl group, an iso-propyl group, a sec-butyl group, and a tert-butyl group are preferable. Methyl group and ethyl group are preferable from the viewpoint of availability of raw materials and low cost, and iso-butyl group, sec-butyl group, and tert-butyl group are preferable because they have high solubility in nonpolar solvents.

As an aromatic hydrocarbon group, C6-C25 is preferable and the aromatic hydrocarbon group derived from a 6-membered monocyclic ring or a 2-5 condensed ring is preferable. Examples thereof include groups derived from a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, fluoranthene ring, and the like.
The aromatic heterocyclic group preferably has 3 to 20 carbon atoms, and furan ring, benzofuran ring, thiophene ring, benzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, pyrrolo Imidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzisoxazole ring, benzoisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, Examples include groups derived from pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, sinoline ring, quinoxaline ring, benzimidazole ring, perimidine ring, quinazoline ring, quinazolinone ring, azulene ring and the like.

As an alkoxy group, C1-C20 is preferable and a methoxy group, an ethoxy group, an isopropyloxy group, a cyclohexyloxy group, an octadecyloxy group etc. are mentioned.
The (hetero) aryloxy group preferably has 3 to 20 carbon atoms, and examples thereof include a phenoxy group, a 1-naphthyloxy group, a 9-anthranyloxy group, and a 2-thienyloxy group.

As an alkylthio group, C1-C20 is preferable and a methylthio group, an ethylthio group, an isopropylthio group, a cyclohexylthio group etc. are mentioned.
The (hetero) arylthio group preferably has 3 to 20 carbon atoms, and examples thereof include a phenylthio group, a 1-naphthylthio group, a 9-anthranylthio group, and a 2-thienylthio group.
The dialkylamino group preferably has 2 to 29 carbon atoms, and examples thereof include a diethylamino group, a diisopropylamino group, and a methylethylamino group.
The alkylarylamino group preferably has 7 to 30 carbon atoms, and examples thereof include a methylphenylamino group.

The diarylamino group preferably has 12 to 30 carbon atoms, and examples thereof include a diphenylamino group and a phenylnaphthylamino group.
In addition, these substituents may further have a substituent, and examples thereof include the alkyl group, aryl group, alkoxy group, and diarylamino group described above.
(About X)
X represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent.

As an aromatic hydrocarbon group, C6-C25 is preferable and the aromatic hydrocarbon group derived from a 6-membered monocyclic ring or a 2-5 condensed ring is preferable. Examples thereof include groups derived from a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, fluoranthene ring, and the like.
The aromatic heterocyclic group preferably has 3 to 20 carbon atoms, and furan ring, benzofuran ring, thiophene ring, benzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, pyrrolo Imidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzisoxazole ring, benzoisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, Examples include groups derived from pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, sinoline ring, quinoxaline ring, benzimidazole ring, perimidine ring, quinazoline ring, quinazolinone ring, azulene ring and the like.

Examples of the substituent that the aromatic hydrocarbon group and the aromatic heterocyclic group may have include those exemplified as the substituent that the triphenylene ring of T may have, and preferable ones. Is the same.
(About m)
m represents an integer of 1 or more. Preferably it is 4 or less, More preferably, it is 2 or less. In particular, 1 is preferable.

(About Ar ¹ and Ar ² )
Ar ¹ and Ar ² each independently represent an aromatic hydrocarbon group that may have a substituent or an aromatic heterocyclic group that may have a substituent.
As an aromatic hydrocarbon group, C6-C25 is preferable and the aromatic hydrocarbon group derived from a 6-membered monocyclic ring or a 2-5 condensed ring is preferable. For example, benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring,
Examples include groups derived from chrysene rings, triphenylene rings, fluoranthene rings, and the like.

  The aromatic heterocyclic group preferably has 3 to 20 carbon atoms, and furan ring, benzofuran ring, thiophene ring, benzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, pyrrolo Imidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzisoxazole ring, benzoisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, Examples include groups derived from pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, sinoline ring, quinoxaline ring, benzimidazole ring, perimidine ring, quinazoline ring, quinazolinone ring, azulene ring and the like.

Examples of the substituent that the aromatic hydrocarbon group and the aromatic heterocyclic group may have include those exemplified as the substituent that the triphenylene ring of T may have, and preferable ones. Is the same.
The substituents may be bonded to form a ring, and a condensed ring may be formed together with Ar ¹ or Ar ² . Examples of the ring formed by combining substituents include cyclohexane, cyclopentane, cyclohexene, cyclopentene, and the like.

(About n)
n represents an integer of 2 or more. Usually 6 or less, preferably 3 or less. 2 is particularly preferable.
When a plurality of partial structures represented by the following formula (1-I) are present in one molecule of the compound represented by the formula (1), they may be the same or different from each other. Good.

(In the formula (1-I), Ar ¹ , Ar ² , and m have the same meaning as in the formula (1).)
<Formula (2)>
Among the compounds represented by the formula (1), a compound represented by the following formula (2) is preferable because it has an emission wavelength close to pure blue.

(In Formula (2), X ¹ and X ² each independently represent an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent. r and p each independently represents an integer greater than or equal to 1. Ar ^{3 to} Ar ⁶ may each independently have an aromatic hydrocarbon group which may have a substituent or a substituent. Represents an aromatic heterocyclic group, R ⁰ represents a substituent, e represents an integer of 0 or more, and when e, r, or p is 2 or more, a plurality of R ⁰ and X ¹ contained in one molecule. And X ² may independently be the same or different.)
(About X ¹ and X ² )
X ¹ and X ² are each independently synonymous with X in the formula (1).

When r or p is 2 or more, the plurality of X ¹ and X ² may be the same or different from each other.
(About r and p)
r and p are each independently synonymous with m in the formula (1).
(About Ar ^{3 to} Ar ⁶ )
Ar ^{3 to} Ar ⁶ are each independently synonymous with Ar ¹ and Ar ² in Formula (1).

When e is 2 or more, the plurality of Ar ^{3 to} Ar ⁶ may be independently the same or different.
(About ^R0 )
R ⁰ represents a substituent. As this substituent, what was illustrated as a substituent which the triphenylene ring in the said Formula (1) may have is mentioned. When e is 2 or more, a plurality of R ⁰ contained in one molecule may be the same or different.

(About e)
e represents an integer of 0 or more. Usually, it is 2 or less, preferably 1 or less.
<Formula (3)>
Among the compounds represented by the formula (2), a compound represented by the following formula (3) is preferable from the viewpoint of emission wavelength and skeleton fastness.

(In the formula (3), Ar ^{3 to} Ar ⁶ , R ⁰ and e have the same meaning as in the formula (2).)
<Formula (4)>
Among the compounds represented by the formula (3), a compound represented by the following formula (4) is preferable because the production is easy.

(In Formula (4), R ^{0 to} R ⁴ each independently represents a substituent. A to e each independently represent an integer of 0 or more.)
(For ^R 0 ^{~R 4)}
R ^{0 to} R ⁴ each independently represents a substituent. Examples of the substituent include those exemplified as the substituent that the triphenylene ring in formula (1) may have, and the same applies to preferable ones.

(About a to e)
a to e have the same meaning as e in the above formula (2).
When any of a to e is 2 or more, the plurality of R ^{0 to} R ⁴ contained in one molecule may be the same or different from each other independently.
<Physical properties of triphenylene compounds>
(Molecular weight)
The molecular weight of the triphenylene compound of the present invention is usually 700 or more and 2000 or less, preferably 1500 or less.

(Crystallization temperature)
The crystallization temperature of the triphenylene compound of the present invention is preferably 200 ° C. or higher, more preferably 250 ° C. or higher, and particularly preferably not observed.
This is because it is particularly preferable that the triphenylene compound of the present invention does not cause crystallization during wet film formation or subsequent heat treatment.

(Vaporization temperature)
The vaporization temperature of the triphenylene compound of the present invention is preferably 500 ° C. or less, more preferably 450 ° C. or less under the condition of 0.001 Pa.
This is because sublimation purification under high vacuum can promote high purity of the compound.

(Glass transition point)
The glass transition point of the triphenylene compound of the present invention is usually 120 ° C. or higher, preferably 125 ° C. or higher, more preferably 130 ° C. or higher, and usually 350 ° C. or lower, preferably 300 ° C. or lower, more preferably 250 ° C. or lower. is there. When the glass transition point is below this range, the thin film produced using the charge transport material of the present invention may be crystallized by heat treatment or energization. Moreover, when a glass transition point exceeds this range, there exists a tendency for the solubility with respect to a solvent to fall.

The glass transition point can be measured by differential scanning calorimetry.
As a measuring device, DSC6220 manufactured by SII Nanotechnology Inc. is used. A sample amount of 2 to 6 mg is put in an aluminum liquid sample container, and the temperature is raised from the room temperature to 400 ° C. to the melting point or more at a heating rate of 10 ° C./min in a nitrogen flow (50 mL / min) atmosphere. In addition,
If no melting point is detected, the temperature is raised to 300 ° C.

Next, after the sample that has been heated once is rapidly cooled to room temperature or lower at a rate of −100 ° C./min or higher, the glass transition point detected when the temperature is increased again at a temperature rising rate of 10 ° C./min, It is defined as the glass transition point of the present invention.
(Solubility in solvent)
When the triphenylene compound of the present invention is dissolved in toluene, the solubility is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, particularly preferably 1.0% by weight or more, and further preferably 2%. 0.0% by weight or more. If the solubility is below this range, the film quality of the thin film formed when wet film formation is reduced tends to be non-uniform. In addition, the selection of various solvents may be limited.

For the measurement of solubility, a glass sample bottle having an internal volume of 2 mL or more and 10 mL or less was charged with solute Xg (usually in a range of 3 mg or more and 10 mg or less) and a solvent (for example, toluene) Yg, and the sample bottle was closed. Stirring, ultrasonic irradiation or heat treatment to promote dissolution as much as possible.
Thereafter, when the precipitate, suspension or layer separation was not confirmed by visual observation or microscopic observation when allowed to stand at room temperature (usually 10 ° C. or more and 30 ° C. or less) for 10 hours or more, the solubility is (X / ( X + Y) × 100)% or more, and when precipitates are confirmed, the solubility is determined to be less than (X / (X + Y) × 100)%.

<Uses of triphenylene compounds>
The triphenylene compound of the present invention is preferably used as a light emitting material and a charge transport material (charge transporting compound), and is preferably used as a light emitting material and a charge transport material for a light emitting layer in an organic electroluminescent device. It is preferable to be used as a material.
In addition, since the production method can be simplified, the triphenylene compound of the present invention is preferably used for an organic layer formed by a wet film forming method.

The reason why the triphenylene compound of the present invention is particularly useful as a light emitting material is presumed as follows.
The luminescent material preferably has the same emission wavelength in the solution state and the solid state.
This is because when the fluorescence wavelength is different between the solution state and the solid state, the solution state shows a wavelength close to pure blue, but the thin film state in an industrially used form may not show a wavelength close to pure blue. .

The reason why the wavelength is different between the solution state and the solid state is presumed to be that, in the solid state, the interaction between molecules becomes strong and an aggregation state occurs.
On the other hand, the triphenylene compound of the present invention has an emission wavelength close to pure blue as in the solution state because the steric hindrance is large and the aggregation state is relaxed even in the solid state where the interaction between molecules tends to be strong. It is.

Thus, the triphenylene compound of the present invention is particularly useful as a light emitting material.
Moreover, it can be used not only for organic electroluminescent elements but also for applications such as solar cell elements and organic transistors.
<Preferred examples of triphenylene compounds>
Hereinafter, although the preferable example of the triphenylene type compound of this invention is illustrated, this invention is not limited to these.

<Method for synthesizing triphenylene compounds>
The triphenylene compound of the present invention can be produced by arbitrarily combining known synthesis methods. Hereinafter, although an example is demonstrated, the manufacturing method of the triphenylene-type compound of this invention is not limited to the following examples.
As described later in Examples, the triphenylene compound of the present invention is preferably synthesized by the following synthesis method.

(In the above synthesis ^method, R ⁰ to R 4, a to e is, ^R 0 ^{to R} 4 in Formula (4), which is synonymous with a to e)
<Method for purifying triphenylene compounds>
As a purification method of the triphenylene compound obtained by synthesis, any known method can be used as long as the effects of the present invention are not significantly impaired.

Specific examples include "Separation and Purification Technology Handbook" (1993, edited by The Chemical Society of Japan), "Advanced separation of trace components and difficult-to-purify substances by chemical conversion method" (1988, published by IPC Corporation). Alternatively, the method described in the section “Separation and purification” of “Experimental Chemistry Course (4th edition) 1” (1990, edited by The Chemical Society of Japan) can be used.
More specifically, extraction (including suspension washing, boiling washing, ultrasonic washing, acid-base washing), adsorption, occlusion, melting, crystallization (including recrystallization from solvent, reprecipitation), distillation (ordinary) Pressure distillation, vacuum distillation), evaporation, sublimation (atmospheric pressure sublimation, vacuum sublimation), ion exchange, dialysis, filtration, ultrafiltration, reverse osmosis, pressure osmosis, zone dissolution, electrophoresis, centrifugation, flotation separation, sedimentation separation , Magnetic separation, various chromatography (shape classification: column, paper, thin layer, capillary. Mobile phase classification: gas, liquid, micelle, supercritical fluid. Separation mechanism: adsorption, distribution, ion exchange, molecular sieve, chelate, gel Filtration, exclusion, affinity) and the like.

The product confirmation and purity analysis methods include gas chromatograph (GC), high performance liquid chromatograph (HPLC), capillary electrophoresis measurement (CE), size exclusion chromatograph (SEC), gel permeation chromatograph (GPC), Cross-fractionation chromatograph (CFC) mass spectrometry (MS, LC / MS, GC / MS, MS / MS), nuclear magnetic resonance apparatus (NMR ( ¹
H-NMR, ¹³ C-NMR)), Fourier transform infrared spectrophotometer (FT-IR), ultraviolet-visible near-infrared spectrophotometer (UV.VIS, NIR), electron spin resonance apparatus (ESR), transmission electron microscope (TEM-EDX) Electron beam microanalyzer (EPMA), metal element analysis (ion chromatograph, inductively coupled plasma-emission spectroscopy (ICP-AES) atomic absorption analysis (AAS) X-ray fluorescence analyzer (XRF)), non-metal Elemental analysis, trace component analysis (ICP-MS, GF-AAS, GD-MS) and the like can be applied as necessary.

<Composition for organic electroluminescence device>
The composition for organic electroluminescent elements of the present invention contains at least the above triphenylene compound and a solvent.
The content of the triphenylene compound in the composition for organic electroluminescent elements is usually 0.5 parts by weight or more, preferably 1 part by weight or more, usually 50 parts by weight or less, preferably 10 parts by weight or less. By setting it within this range, the effect of improving the light emission efficiency and lowering the voltage of the element can be obtained. In addition, the said triphenylene type compound may be contained only 1 type in the composition, and may be contained in combination of 2 or more type.

The solvent contained in the composition is a volatile liquid component used for forming a layer containing a triphenylene compound by wet film formation.
The solvent is not particularly limited as long as the solute dissolves well, but the following examples are preferable.
For example, alkanes such as n-decane, cyclohexane, ethylcyclohexane, decalin, and bicyclohexane; aromatic hydrocarbons such as toluene, xylene, methicylene, cyclohexylbenzene, and tetralin; halogenated fragrances such as chlorobenzene, dichlorobenzene, and trichlorobenzene Group hydrocarbons: 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethyl Aromatic ethers such as anisole and diphenyl ether; aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate; Alicyclic ketones such as Sanone, Cyclooctanone and Fencon; Alicyclic alcohols such as cyclohexanol and cyclooctanol; Aliphatic ketones such as methyl ethyl ketone and dibutyl ketone; Aliphatic alcohols such as butanol and hexanol; Ethylene And aliphatic ethers such as glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA).

Of these, alkanes and aromatic hydrocarbons are preferable. One of these solvents may be used alone, or two or more thereof may be used in any combination and ratio.
In order to obtain a more uniform film, it is preferable that the solvent evaporates from the liquid film immediately after the film formation at an appropriate rate. For this reason, the boiling point of the solvent is usually 80 ° C. or higher, preferably 100 ° C. or higher, more preferably 120 ° C. or higher, and usually 270 ° C. or lower, preferably 250 ° C. or lower, more preferably 230 ° C. or lower.

  The amount of the solvent used is preferably 10 parts by weight or more, more preferably 50 parts by weight or more, particularly preferably 80 parts by weight or more, and preferably 99.95 parts per 100 parts by weight of the composition for organic electroluminescent elements. The amount is not more than parts by weight, more preferably not more than 99.9 parts by weight, particularly preferably not more than 99.8 parts by weight. When the content is lower than the lower limit, the viscosity becomes too high, and the film forming workability may be lowered. On the other hand, if the value exceeds the upper limit, the film thickness obtained by removing the solvent after film formation cannot be obtained, so that film formation tends to be difficult.

In addition to the triphenylene compound and the solvent of the present invention, the composition for an organic electroluminescent device of the present invention can contain a charge transporting compound used for an organic electroluminescent device, particularly a light emitting layer.
When the light emitting layer is formed using the composition for organic electroluminescent elements of the present invention, the triphenylene compound of the present invention may be used as a host material and another charge transporting compound may be included as a dopant material. The triphenylene compound of the present invention may be used as a dopant material, and another charge transporting compound may be contained as a host material. Further, both the dopant material and the host material may be the triphenylene compound of the present invention.

  As other charge transporting compounds, those conventionally used as materials for organic electroluminescence devices can be used. For example, naphthalene, perylene, anthracene, pyrene, triphenylene, chrysene, naphthacene, phenanthrene, coronene, fluoranthene, benzophenanthrene, fluorene, acetonaphthofluoranthene, coumarin, p-bis (2-phenylethenyl) benzene and derivatives thereof , Quinacridone derivatives, DCM (4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran) compounds, benzopyran derivatives, rhodamine derivatives, benzothioxanthene derivatives, azabenzothioxanthene, arylamino groups And a condensed aromatic ring compound substituted with an arylamino group, and a styryl derivative substituted with an arylamino group.

The other charge transporting compound is usually 1 part by weight or more and usually 50 parts by weight or less, preferably 30 parts by weight or less, based on 100 parts by weight of the composition.
The composition for organic electroluminescent elements may further contain other compounds in addition to the above-described compounds as necessary. For example, in addition to the above solvent, another solvent may be contained. Examples of such a solvent include amides such as N, N-dimethylformamide and N, N-dimethylacetamide, and dimethyl sulfoxide. One of these may be used alone, or two or more may be used in any combination and ratio.

Moreover, you may contain various additives, such as a leveling agent and an antifoamer, for the purpose of the improvement of film formability.
<Organic electroluminescent device>
The organic electroluminescent element of the present invention is an organic electroluminescent element having an anode, a cathode, and an organic layer provided between the anode and the cathode, and the organic layer contains the triphenylene compound of the present invention. It is characterized by doing. Especially, it is preferable to include the organic layer formed with the wet film-forming method using the composition for organic electroluminescent elements of this invention.

The organic layer may be composed of one layer, or may be composed of two or more layers, and any layer may contain the triphenylene compound of the present invention. In addition to the organic layer, a layer made of an inorganic compound may be provided between the anode and the cathode.
Hereinafter, although it demonstrates according to the element structure of FIG. 1, the structure of the organic electroluminescent element of this invention is not limited to these.

(substrate)
The substrate serves as a support for the organic electroluminescence device, and quartz or glass plates, metal plates or metal foils, plastic films or sheets are used. In particular, a glass plate or a transparent synthetic resin plate such as polyester, polymethacrylate, polycarbonate, or polyethersulfone is preferable. When using a synthetic resin substrate, it is necessary to pay attention to gas barrier properties. If the gas barrier property of the substrate is too small, the organic electroluminescent element may be deteriorated by the outside air that has passed through the substrate, which is not preferable. For this reason, a method of providing a gas barrier property by providing a dense silicon oxide film or the like on at least one surface of the synthetic resin substrate is also a preferable method.

(anode)
An anode is provided on the substrate. The anode plays a role of hole injection into a layer (hole injection layer or the like) on the light emitting layer side.
This anode is usually made of metal such as aluminum, gold, silver, nickel, palladium, platinum, metal oxide such as oxide of indium and / or tin, metal halide such as copper iodide, carbon black, or poly It is composed of conductive polymers such as (3-methylthiophene), polypyrrole, and polyaniline.

  In general, the anode is often formed by a sputtering method, a vacuum deposition method, or the like. In addition, when forming an anode using fine metal particles such as silver, fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, or conductive polymer fine powder, an appropriate binder resin solution is used. The anode can also be formed by dispersing and coating the substrate. Further, in the case of a conductive polymer, a thin film can be directly formed on a substrate by electrolytic polymerization, or an anode can be formed by applying a conductive polymer on a substrate (Appl. Phys. Lett., 60 (Vol. 2711, 1992).

The anode usually has a single-layer structure, but it can also have a laminated structure composed of a plurality of materials if desired.
The thickness of the anode varies depending on the required transparency. When transparency is required, the visible light transmittance is usually 60% or more, preferably 80% or more. In this case, the thickness of the anode is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably about 500 nm or less. When it may be opaque, the thickness of the anode is arbitrary and may be the same as the substrate. It is also possible to laminate different conductive materials on the anode.

The surface of the anode is treated with ultraviolet (UV) / ozone, oxygen plasma, or argon plasma for the purpose of removing impurities adhering to the anode and adjusting the ionization potential to improve hole injection. Is preferred.
(Hole injection layer)
The method for forming the hole injection layer according to the present invention is not particularly limited, but the hole injection layer is preferably formed by wet film formation from the viewpoint of reducing dark spots. In addition, the wet film forming method is more industrially superior in that a homogeneous and defect-free thin film can be obtained as compared with the conventional vacuum deposition method, the time for formation is short.

  Here, the wet film formation (method) in the present invention is a spin coating method, dip coating method, die coating method, bar coating method, blade coating method, roll coating method, spray coating method, capillary coating method, ink jet method, screen printing. A method of forming a film using an ink containing a solvent, such as a printing method, a gravure printing method, a flexographic printing method, and an offset printing. From the viewpoint of easy patterning, a die coating method, a roll coating method, a spray coating method, an ink jet method, or a flexographic printing method is preferable.

When forming a hole injection layer by wet film formation, the composition for film formation (hole injection layer formation) is usually mixed with an appropriate solvent (solvent for hole injection layer). Composition), and this hole injection layer forming composition is applied onto a layer corresponding to the lower layer of the hole injection layer (usually an anode) by an appropriate technique, and is then formed and dried. As a result, a hole injection layer is formed.
(Hole transporting compound)
The composition for forming a hole injection layer usually contains at least a hole transporting compound and a solvent as a material for the hole injection layer. The hole transporting compound may be a low molecular compound or a high molecular compound as long as it is a compound having a hole transporting property, which is usually used for a hole injection layer of an organic electroluminescence device. . Moreover, you may form a positive hole injection layer with a wet film-forming method using the triphenylene type compound of this invention as a positive hole transportable compound.

  The hole transporting compound is preferably a compound having an ionization potential of 4.5 eV to 6.0 eV from the viewpoint of a charge injection barrier from the anode to the hole injection layer. Examples of hole transporting compounds include aromatic amine compounds, phthalocyanine derivatives, porphyrin derivatives, oligothiophene derivatives, polythiophene derivatives, benzylphenyl compounds, compounds in which tertiary amines are linked by a fluorene group, hydrazone compounds, silazane compounds, silanamines Derivatives, phosphamine derivatives, quinacridone compounds, phthalocyanine derivatives, and the like.

Of these, aromatic amine compounds are preferred from the viewpoints of amorphousness and visible light transmittance. An aromatic tertiary amine compound is particularly preferable. Here, the aromatic tertiary amine compound is a compound having an aromatic tertiary amine structure, and includes a compound having a group derived from an aromatic tertiary amine. The kind of the aromatic tertiary amine compound is not particularly limited, but from the viewpoint of uniform light emission due to the surface smoothing effect, a polymer compound having a weight average molecular weight of 1,000 or more and 1,000,000 or less (a polymer in which repeating units are linked) is more preferable. . Preferable examples of the aromatic tertiary amine polymer compound include a polymer compound having a repeating unit represented by the following formula (I).

(In formula (I), Ar ⁷ and Ar ⁸ each independently represent an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent. Ar ^{9 to} Ar ¹¹ each independently represents a divalent aromatic hydrocarbon group which may have a substituent, or a divalent aromatic heterocyclic group which may have a substituent. Y represents a linking group selected from the following group of linking groups, and two groups bonded to the same N atom among Ar ^{7 to} Ar ¹¹ are bonded to each other to form a ring. May be.)

(In said each formula, Ar < ¹² > -Ar < ²² > is respectively independently 1 derived from the aromatic hydrocarbon ring which may have a substituent, or the aromatic heterocycle which may have a substituent. R ⁵ and R ⁶ each independently represents a hydrogen atom or an arbitrary substituent.
As Ar ^{7 to} Ar ²² , a monovalent or divalent group derived from any aromatic hydrocarbon ring or aromatic heterocyclic ring is applicable. These may be the same or different from each other. The group derived from the aromatic hydrocarbon ring and / or aromatic heterocycle of Ar ^{7 to} Ar ²² may further have a substituent. The molecular weight of the substituent is usually 400 or less, preferably about 250 or less. Ar ⁷ and Ar ⁸ are preferably monovalent groups derived from a benzene ring, a naphthalene ring, a phenanthrene ring, a thiophene ring, or a pyridine ring from the viewpoint of the solubility, heat resistance, and hole injection / transport properties of the polymer compound. More preferred are a phenyl group and a naphthyl group. In addition, as Ar ^{9 to} Ar ¹¹ , a divalent group derived from a benzene ring, a naphthalene ring, a triphenylene ring, or a phenanthrene ring is preferable from the viewpoint of heat resistance and hole injection / transport properties including a redox potential. A group, a biphenylene group, and a naphthylene group are more preferable.

Specific examples of the aromatic tertiary amine polymer compound having a repeating unit represented by the formula (I) include, for example, those described in WO 2005/089024.
The hole transporting compound used as the material for the hole injection layer may contain any one of these compounds alone, or may contain two or more. In the case of containing two or more kinds of hole transporting compounds, the combination is arbitrary, but one or more kinds of aromatic tertiary amine polymer compounds and one or two kinds of other hole transporting compounds. It is preferable to use the above in combination.

(Electron-accepting compound)
The composition for forming a hole injection layer preferably contains an electron accepting compound. The electron-accepting compound is preferably a compound having an oxidizing power and the ability to accept one electron from the above-described hole transporting compound, specifically, a compound having an electron affinity of 4 eV or more is preferable, and 5 eV or more. The compound which is the compound of these is further more preferable. The electron-accepting compound is selected from the group consisting of, for example, triarylboron compounds, metal halides, Lewis acids, organic acids, onium salts, salts of arylamines and metal halides, and salts of arylamines and Lewis acids. 1 type, or 2 or more types of compounds etc. which are mentioned. More specifically, an onium salt substituted with an organic group such as 4-isopropyl-4′-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate or triphenylsulfonium tetrafluoroborate (WO 2005/089024) High-valent inorganic compounds such as iron (III) chloride (Japanese Patent Laid-Open No. 11-251067) and ammonium peroxodisulfate; cyano compounds such as tetracyanoethylene, tris (pendafluorophenyl) borane (Japanese Patent Laid-Open No. 2003-31365) Aromatic boron compounds; fullerene derivatives; iodine and the like. These electron-accepting compounds can improve the conductivity of the hole injection layer by oxidizing the hole transport material. The content of the electron-accepting compound with respect to the hole transport material is usually 0.1 mol% or more, preferably 1 mol% or more. However, it is usually 100 mol% or less, preferably 40 mol% or less.

(solvent)
At least one of the solvents used in the wet film formation method is preferably a compound that can dissolve the material of the hole injection layer. The boiling point of the solvent is usually 110 ° C. or higher, preferably 140 ° C. or higher, particularly 200 ° C. or higher, usually 400 ° C. or lower, and preferably 300 ° C. or lower. If the boiling point of the organic solvent is too low, the drying speed is high and the film quality may be deteriorated. Moreover, when the boiling point of the organic solvent is too high, it is necessary to increase the temperature of the high drying process. Therefore, it may adversely affect other layers and the glass substrate. Examples of the solvent include ether solvents, ester solvents, aromatic hydrocarbon solvents, amide solvents, and the like. Specifically, examples of the ether solvent include aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol-1-monomethyl ether acetate (PGMEA); 1,2-dimethoxybenzene, 1,3- And aromatic ethers such as dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, and 2,4-dimethylanisole.

Examples of the ester solvent include aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate.
Examples of the aromatic hydrocarbon solvent include toluene, xylene, cyclohexylbenzene, 3-isopropylpropylphenyl, 1,2,3,4-tetramethylbenzene, 1,4-diisopropylbenzene, cyclohexylbenzene, and methylnaphthalene. Can be mentioned.

Examples of the amide solvent include N, N-dimethylformamide, N, N-dimethylacetamide, and the like.
In addition, dimethyl sulfoxide and the like can also be used.
These solvent may use only 1 type and may use 2 or more types by arbitrary combinations and a ratio.

Among the solvents described above, a solvent having a high ability to dissolve the material of the hole injection layer (dissolving ability) or a high affinity with the material is preferable. This is because a composition having a concentration excellent in the efficiency of the film forming process can be prepared by arbitrarily setting the concentration of the composition for forming the hole injection layer.
(concentration)
The concentration of the hole transporting compound in the composition for forming a hole injection layer is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.01% by weight or more, preferably in terms of film thickness uniformity. Is 0.1% by weight or more, more preferably 0.5% by weight or more, and usually 70% by weight or less, preferably 60% by weight or less, more preferably 50% by weight or less. If the concentration is too high, film thickness unevenness may occur. If the concentration is too low, defects may occur in the formed organic layer.

(Other things that may be included)
As a material for the hole injection layer, other components may be further contained in addition to the hole transporting compound and the electron accepting compound as long as the effects of the present invention are not significantly impaired. Examples of other components include various light emitting materials, electron transporting compounds, binder resins, and coating property improving agents. In addition, only 1 type may be used for another component and it may use 2 or more types together by arbitrary combinations and ratios.

After preparing the composition for forming the hole injection layer, the composition is applied to the layer corresponding to the lower layer of the hole injection layer (usually an anode) by wet film formation, and dried to dry the hole. An injection layer is formed.
After film formation, it is usually dried by heating or the like. The heating means used in the heating step is not limited as long as the effects of the present invention are not significantly impaired. Examples of the heating means include a clean oven, a hot plate, infrared rays, a halogen heater, and microwave irradiation. Among them, a clean oven and a hot plate are preferable in order to uniformly apply heat to the entire film.

In the case of layer formation by vacuum deposition, one or more materials (hole transporting compound, electron accepting compound, etc.) are put in a crucible installed in a vacuum vessel (two or more materials are added). If it is used, put it in each crucible), evacuate the inside of the vacuum vessel to about 10 ⁻⁴ Pa with an appropriate vacuum pump, then heat the crucible (if using more than one material, heat each crucible) ), Evaporate by controlling the evaporation amount (evaporation is controlled by independently controlling the evaporation amount when using two or more materials), and form a hole injection layer on the anode of the substrate placed facing the crucible Let In addition, when using 2 or more types of materials, they can also be put into a crucible, can be heated and evaporated, and can be used for hole injection layer formation.

The thickness of the hole injection layer is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably 500 nm or less.
(Hole transport layer)
The organic electroluminescent element of the present invention preferably has a hole transport layer.
The method for forming the hole transport layer according to the present invention is not particularly limited, but the hole transport layer is preferably formed by wet film formation from the viewpoint of reducing dark spots.

The hole transport layer can be formed on the hole injection layer when a hole injection layer is provided, or on the anode when there is no hole injection layer.
The material that can be used for the hole transport layer is preferably a material that has a high hole transport property and can efficiently transport the injected holes. Therefore, it is preferable that the ionization potential is small, the transparency to visible light is high, the hole mobility is large, the stability is high, and impurities that become traps are not easily generated during manufacturing or use. In many cases, it is in contact with the light-emitting layer, so it is preferable not to quench the light emitted from the light-emitting layer or reduce the efficiency by forming an exciplex with the light-emitting layer.

As a material for such a hole transport layer, any material that has been conventionally used as a material for a hole transport layer may be used. For example, what was illustrated as a hole transportable compound used for the above-mentioned hole injection layer is mentioned. In addition, two or more condensed aromatic rings including two or more tertiary amines represented by 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl are substituted with nitrogen atoms. Aromatic diamine (Japanese Patent Laid-Open No. 5-234681), 4,4 ', 4''-
An aromatic amine compound having a starburst structure such as tris (1-naphthylphenylamino) triphenylamine (J. Lumin., 72-74, 985, 1997), a fragrance comprising a tetramer of triphenylamine Group amine compounds (Chem. Commun., 2175, 1996), spiro compounds such as 2,2 ′, 7,7′-tetrakis- (diphenylamino) -9,9′-spirobifluorene (Synth. Metals, 91, 209 (1997), carbazole derivatives such as 4,4′-N, N′-dicarbazolebiphenyl, and the like. Further, for example, polyvinyl carbazole, polyvinyl triphenylamine (Japanese Patent Laid-Open No. 7-53953), polyarylene ether sulfone (Polym. Adv. Tech., 7, 33, 1996) containing tetraphenylbenzidine, etc. Can be mentioned.

In the case of forming the hole transport layer by wet film formation, a hole transport layer forming composition is prepared in the same manner as in the formation of the hole injection layer, followed by film formation and heat drying. The composition for forming a hole transport layer contains a solvent in addition to the hole transport compound. The solvent is the same as that used in the composition for forming a hole injection layer. The film forming conditions, heat drying conditions, and the like are the same as in forming the hole injection layer.
In addition, also when forming a positive hole transport layer by vacuum evaporation, the film-forming conditions etc. are the same as formation of the said hole injection layer.

The hole transport layer may contain various light emitting materials, electron transport compounds, binder resins, coatability improvers, and the like in addition to the hole transport compound.
The hole transport layer may be a layer formed by crosslinking a crosslinkable compound. The crosslinkable compound is a compound having a crosslinkable group, which will be described later, and forms a network polymer compound by crosslinking. The crosslinkable compound may be a low molecular compound or a high molecular compound. The crosslinkable compound may have only 1 type, and may have 2 or more types by arbitrary combinations and ratios.

Moreover, a crosslinkable group means the group which reacts with the same or different group of the other molecule | numerator located in the vicinity, and produces | generates a novel chemical bond. For example, the group which reacts with the same or different group of the other molecule | numerator located in the vicinity by irradiation of a heat | fever and / or active energy ray, and produces | generates a novel chemical bond is mentioned.
Examples of crosslinkable groups include cyclic ethers such as oxetane groups and epoxy groups; unsaturated double bonds such as vinyl groups, trifluorovinyl groups, styryl groups, acrylic groups, methacryloyl groups, cinnamoyl groups; benzocyclobutane groups, etc. Is mentioned.

  There is no particular limitation on the number of crosslinkable groups that the monomer, oligomer or polymer having a crosslinkable group has, but it is usually less than 2.0, preferably 0.8 or less, more preferably 0.5 or less per charge transport unit. Number is preferred. This is to keep the relative dielectric constant of the charge transport film forming material within a suitable range. Moreover, if the number of crosslinkable groups is too large, reactive active species are generated, which may adversely affect other materials. Here, when the material forming the network polymer compound is a low molecular compound, the charge transport unit is a low molecular compound itself and indicates a skeleton (main skeleton) excluding a crosslinkable group. Even when other kinds of low molecular weight compounds are mixed, the main skeleton of each low molecular weight compound is shown. In the case where the material forming the network polymer compound is a polymer compound, in the case of a structure in which conjugation is broken organically, the repeated structure is used as a charge transport unit. Further, in the case of a structure in which conjugation is widely linked, the minimum repeating structure exhibiting charge transporting properties indicates the structure of a low molecular compound. Examples include polycyclic aromatics such as naphthalene, triphenylene, phenanthrene, tetracene, chrysene, pyrene, and perylene, fluorene, triphenylene, carbazole, triarylamine, tetraarylbenzidine, 1,4-bis (diarylamino) benzene, and the like. It is done.

  Furthermore, it is preferable to use a hole transporting compound having a crosslinkable group as the crosslinkable compound. Examples of hole transporting compounds include nitrogen-containing aromatic compound derivatives such as pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, phenanthroline derivatives, carbazole derivatives, phthalocyanine derivatives, porphyrin derivatives; triphenylamine derivatives Silole derivatives; oligothiophene derivatives, condensed polycyclic aromatic derivatives, metal complexes and the like. Among them, nitrogen-containing aromatic derivatives such as pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, phenanthroline derivatives, carbazole derivatives; triphenylamine derivatives, silole derivatives, condensed polycyclic aromatic derivatives, metal complexes, etc. Particularly preferred are triphenylamine derivatives. The molecular weight of the crosslinkable compound is usually 5000 or less, preferably 2500 or less, preferably 300 or more, more preferably 500 or more.

In order to form a hole transport layer by crosslinking a crosslinkable compound, a coating liquid (composition for forming a hole transport layer) in which a crosslinkable compound is dissolved or dispersed in a solvent is usually prepared and subjected to wet film formation. Form a film and crosslink.
In addition to the crosslinkable compound, the coating solution may contain an additive that accelerates the crosslinking reaction. Examples of additives that accelerate the crosslinking reaction include: crosslinking initiators and crosslinking accelerators such as alkylphenone compounds, acylphosphine oxide compounds, metallocene compounds, oxime ester compounds, azo compounds, onium salts; condensed polycyclic hydrocarbons; And photosensitizers such as porphyrin compounds and diaryl ketone compounds. Further, it may contain a coating property improving agent such as a leveling agent and an antifoaming agent; an electron accepting compound: a binder resin, and the like.

The solvent used for the coating solution is the same as that exemplified as the solvent for forming the hole injection layer. In the coating solution, the crosslinkable compound is usually 0.01% by weight or more, preferably 0.05% by weight or more, more preferably 0.1% by weight or more, usually 50% by weight or less, preferably 20% by weight or less, more preferably. Contains 10% by weight or less.
After forming the coating solution on the lower layer, the crosslinkable compound is crosslinked to form a network polymer by heating and / or irradiation with electromagnetic energy such as light. The heating method after film formation is not particularly limited, and examples thereof include heat drying and reduced pressure drying. As conditions for the heat drying, the layer formed at 120 ° C. or higher, preferably 400 ° C. or lower is heated. The heating time is usually 1 minute or longer, preferably 24 hours or shorter. The heating means is not particularly limited, and means such as placing a laminated body having a deposited layer on a hot plate or heating in an oven is used. For example, conditions such as heating on a hot plate at 120 ° C. or more for 1 minute or more can be used.

  In the case of irradiation with electromagnetic energy such as light, a method of irradiating directly using an ultraviolet / visible / infrared light source such as an ultra-high pressure mercury lamp, a high-pressure mercury lamp, a halogen lamp or an infrared lamp, or the above-mentioned light source is incorporated. Examples include a mask aligner and a method of irradiation using a conveyor type light irradiation device. In electromagnetic energy irradiation other than light, for example, there is a method of irradiation using a device that irradiates a microwave generated by a magnetron, a so-called microwave oven. As the irradiation time, it is preferable to set conditions necessary for reducing the solubility of the film, but irradiation is usually performed for 0.1 seconds or longer, preferably 10 hours or shorter.

Irradiation of electromagnetic energy such as heating and light may be performed individually or in combination. When combined, the order of implementation is not particularly limited.
In order to reduce the amount of moisture contained in the layer and / or the moisture adsorbed on the surface after the implementation, the electromagnetic energy irradiation including heating and light is preferably performed in an atmosphere not containing moisture such as a nitrogen gas atmosphere. For the same purpose, when combined with heating and / or irradiation with electromagnetic energy such as light, it is particularly preferable to perform at least the step immediately before the formation of the organic light emitting layer in an atmosphere containing no moisture such as a nitrogen gas atmosphere.

The thickness of the hole transport layer is usually 5 nm or more, preferably 10 nm or more, and usually 300 nm or less, preferably 100 nm or less.
(Light emitting layer)
The light emitting layer in the organic electroluminescent device of the present invention is preferably formed by a wet film forming method using the composition for organic electroluminescent device of the present invention.

The film formation temperature at the time of film formation is not limited, but in order to prevent film loss due to the occurrence of crystals and aggregation in the composition, it is preferably 10 ° C. or higher, more preferably 13 ° C. or higher, further preferably 16 ° C. or higher, Moreover, 50 degrees C or less is preferable and 40 degrees C or less is more preferable.
The relative humidity during film formation is not limited, but is usually 0.01 ppm or more, preferably 0.05 ppm or more, more preferably 0.1 ppm or more, usually 80% or less, preferably 60% or less, more preferably 15% or less, More preferably, it is 1% or less, and particularly preferably 100 ppm or less. If the relative humidity is too small, it is difficult to control the film forming conditions, and a stable environment cannot be maintained. On the other hand, if it is too large, moisture adsorption on the organic layer will increase, and when an organic electroluminescent element is formed, the drive voltage and the life may be adversely affected.

After film formation, it is usually heated and dried. Examples of the heating means include a clean oven, a hot plate, infrared rays, a halogen heater, and microwave irradiation. Among them, a clean oven and a hot plate are preferable in order to uniformly apply heat to the entire film.
The heating direction in the heating step is not limited as long as the effects of the present invention are not significantly impaired. As an example of the heating direction, for example, by mounting a base material on a hot plate and heating the coating film through the hot plate, the coating film is removed from the lower surface of the substrate (the surface on which the organic layer is not coated). A method of heating, a method of heating the coating film from all directions, front, back, left, and right by putting the substrate into a clean oven can be mentioned.

  The heating temperature in the heating step is not particularly limited as long as the effect of the present invention is not significantly impaired, but is usually 90 ° C or higher, preferably 100 ° C or higher, and usually 200 ° C or lower, preferably 140 ° C or lower. Is preferred. If the temperature is too high, components of the composition for organic electroluminescent elements of the present invention may diffuse into other layers, and if it is too low, a trace amount of residual solvent may not be removed sufficiently. Moreover, when heating the mixed solvent in which two or more types of the solvent shown above are contained, it is preferable to heat at the temperature more than the boiling point of at least one type of solvent.

  The heating time in the heating step is not limited as long as the effect of the present invention is not significantly impaired, but is preferably 15 minutes or more, more preferably 30 minutes or more, further preferably 1 hour or more, and preferably 6 hours or less, more preferably Is 3 hours or less, more preferably 2 hours or less. This makes it possible to sufficiently insolubilize the coating film. If the heating time is too long, the components of the other layers tend to diffuse into the light emitting layer, and if it is too short, sufficient homogeneity in the film of the light emitting layer cannot be obtained.

The thickness of the light emitting layer is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 3 nm or more, preferably 5 nm or more, and usually 200 nm or less, preferably 100 nm or less. If the thickness of the light emitting layer is too thin, defects may occur in the light emitting layer, and if it is too thick, the driving voltage of the device may increase.
When a light emitting layer is not formed using the composition for organic electroluminescent elements of the present invention, that is, when the composition for organic electroluminescent elements of the present invention is used for other layers, the light emitting layer is a conventional organic electroluminescent element. It can be formed by materials and methods used for the light emitting layer.

[6] Hole blocking layer A hole blocking layer may be provided on the light emitting layer. The hole blocking layer has a role of blocking holes moving from the anode from reaching the cathode and a role of efficiently transporting electrons injected from the cathode toward the light emitting layer.
The physical properties required for the material constituting the hole blocking layer include high electron mobility, low hole mobility, large energy gap (difference between HOMO and LUMO), and excited triplet level (T1). It is expensive. As a material for the hole blocking layer satisfying such conditions, for example, bis (2-methyl-8-quinolinolato), (phenolato) aluminum, bis (2-methyl-8-quinolinolato), (triphenylsilanolato) Mixed ligand complexes such as aluminum, metal complexes such as bis (2-methyl-8-quinolato) aluminum-μ-oxo-bis- (2-methyl-8-quinolinato) aluminum binuclear metal complexes, distyrylbiphenyl derivatives Styryl compounds such as JP-A-11-242996 and triazole derivatives such as 3- (4-biphenylyl) -4-phenyl-5 (4-tert-butylphenyl) -1,2,4-triazole Kaihei 7-41759) and phenanthroline derivatives such as bathocuproine (Japanese Patent Laid-Open No. 10-79297). It is. Further, a compound having at least one pyridine ring substituted at the 2,4,6-positions described in International Publication No. 2005-022962 is also preferable as a material for the hole blocking layer. In addition, the material of a hole-blocking layer may use only 1 type, and may use 2 or more types together by arbitrary combinations and ratios. There is no restriction | limiting in the formation method of a hole-blocking layer. Therefore, it can be formed by a wet film formation method, a vacuum deposition method, or other methods. A vacuum deposition method is preferred.

The thickness of the hole blocking layer is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.3 nm or more, preferably 0.5 nm or more, and usually 100 nm or less, preferably 50 nm or less.
[7] Electron transport layer For example, an electron transport layer may be provided between the cathode and the light emitting layer. The electron transport layer is provided for the purpose of further improving the light emission efficiency of the device, and can efficiently transport electrons injected from the cathode between the electrodes to which an electric field is applied in the direction of the light emitting layer. Is formed.

  The electron transporting compound used for the electron transporting layer is usually a compound that has high electron injection efficiency from the cathode or the electron injection layer and has high electron mobility and can efficiently transport the injected electrons. Is used. Examples of the compound satisfying such conditions include metal complexes such as aluminum complexes of 8-hydroxyquinoline (Japanese Patent Laid-Open No. 59-194393), metal complexes of 10-hydroxybenzo [h] quinoline, oxadiazole derivatives , Distyrylbiphenyl derivatives, silole derivatives, 3-hydroxyflavone metal complexes, 5-hydroxyflavone metal complexes, benzoxazole metal complexes, benzothiazole metal complexes, trisbenzimidazolylbenzene (US Pat. No. 5,645,948), quinoxaline compounds ( JP-A-6-207169), phenanthroline derivative (JP-A-5-331459), 2-t-butyl-9,10-N, N'-dicyanoanthraquinonediimine, n-type hydrogenated amorphous silicon carbide , N-type zinc sulfide, n-type zinc Such as emissions of zinc, and the like. In addition, only 1 type may be used for the material of an electron carrying layer, and 2 or more types may be used together by arbitrary combinations and a ratio.

There is no restriction | limiting in the formation method of an electron carrying layer. Therefore, it can be formed by a wet film formation method, a vacuum deposition method, or other methods. A vacuum deposition method is preferred.
The thickness of the electron transport layer is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 1 nm or more, preferably 5 nm or more, and usually 300 nm or less, preferably 100 nm or less.

[8] Electron injection layer The electron injection layer plays a role of efficiently injecting electrons injected from the cathode into the light emitting layer. In order to perform electron injection efficiently, the material for forming the electron injection layer is preferably a metal having a low work function. Examples include alkali metals such as sodium and cesium, and alkaline earth metals such as barium and calcium. The film thickness is usually preferably from 0.1 nm to 5 nm.

Furthermore, an organic electron transport compound represented by a metal complex such as a nitrogen-containing heterocyclic compound such as bathophenanthroline or an aluminum complex of 8-hydroxyquinoline is doped with an alkali metal such as sodium, potassium, cesium, lithium, or rubidium ( (As described in JP-A-10-270171, JP-A-2002-1000047, JP-A-2002-1000048, etc.), it is possible to improve the electron injection / transport properties and achieve excellent film quality. preferable. Further, for example, an ultra-thin insulating film (0.1 to 5 nm) formed of lithium fluoride (LiF), magnesium fluoride (MgF ₂ ), lithium oxide (Li ₂ O), cesium carbonate (II) (CsCO ₃ ), or the like. ) Is also an effective method for improving the efficiency of the device (Applied Physics Letters, 1997, Vol. 70, pp. 152; Japanese Patent Laid-Open No. 10-74586; IEEE Transactions on Electron Devices, 1997) , Vol. 44, pp. 1245; see SID 04 Digest, pp. 154, etc.).

In this case, the film thickness is usually 5 nm or more, preferably 10 nm or more, and is usually 200 nm or less, preferably 100 nm or less.
In addition, only 1 type may be used for the material of an electron injection layer, and 2 or more types may be used together by arbitrary combinations and a ratio.
There is no restriction | limiting in the formation method of an electron injection layer. Therefore, it can be formed by a wet film formation method, a vacuum deposition method, or other methods.

[9] Cathode The cathode plays a role of injecting electrons into the layer on the light emitting layer side.
As the material of the cathode, it is possible to use the material used for the anode described above, but in order to perform electron injection efficiently, a metal having a low work function is preferable, for example, tin, magnesium, indium, calcium, A suitable metal such as aluminum or silver or an alloy thereof is used. Specific examples include low work function alloy electrodes such as magnesium-silver alloy, magnesium-indium alloy, and aluminum-lithium alloy. In addition, only 1 type may be used for the material of a cathode, and 2 or more types may be used together by arbitrary combinations and a ratio.

The thickness of the cathode is usually the same as that of the anode.
Further, for the purpose of protecting the cathode made of a low work function metal, it is preferable to further stack a metal layer having a high work function and stable to the atmosphere because the stability of the device is increased. For this purpose, for example, metals such as aluminum, silver, copper, nickel, chromium, gold and platinum are used. In addition, these materials may be used only by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

[10] Other layers The organic electroluminescent element obtained by the production method of the present invention may have another configuration without departing from the gist thereof. For example, as long as the performance is not impaired, an arbitrary layer may be provided between the anode and the cathode in addition to the layers described above, and an arbitrary layer may be omitted.

[11] Electron blocking layer The electron blocking layer prevents electrons moving from the light emitting layer from reaching the hole transport layer and the hole injection layer, thereby regenerating the holes and electrons in the light emitting layer. There are a role of increasing the coupling probability and confining the generated excitons in the light emitting layer, and a role of efficiently transporting holes injected from the hole transport layer and the hole injection layer in the direction of the light emitting layer. In particular, it is effective when a phosphorescent material or a blue light emitting material is used as the light emitting material.

  The characteristics required for the electron blocking layer include high hole transportability, a large energy gap (difference between HOMO and LUMO), and a high excited triplet level (T1). Furthermore, in the present invention, when the light emitting layer is formed as an organic layer according to the present invention by a wet film formation method, the electron blocking layer is also required to be compatible with the wet film formation. Examples of the material used for such an electron blocking layer include a copolymer of dioctylfluorene and triphenylamine typified by F8-TFB (described in International Publication No. 2004/084260). In addition, the material of an electron blocking layer may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

There is no restriction | limiting in the formation method of an electron blocking layer. Therefore, it can be formed by a wet film formation method, a vacuum deposition method, or other methods.
Moreover, in the layer structure demonstrated above, it is also possible to laminate | stack components other than a board | substrate in reverse order. For example, in the layer configuration of FIG. 1, other components are provided on the substrate in order from the cathode.

Furthermore, it is also possible to constitute an organic electroluminescent element by laminating components other than the substrate between two substrates, at least one of which has transparency.
In addition, a structure in which a plurality of components (light emitting units) other than the substrate are stacked in a plurality of layers (a structure in which a plurality of light emitting units are stacked) may be employed. In that case, instead of the interface layer between the steps (between the light emitting units) (when the anode is ITO and the cathode is Al, these two layers), for example, a charge made of vanadium pentoxide (V ₂ O ₅ ) or the like. When a generation layer (Carrier Generation Layer: CGL) is provided, a barrier between steps is reduced, which is more preferable from the viewpoint of light emission efficiency and driving voltage.

Furthermore, the organic electroluminescent device obtained by the production method of the present invention may be configured as a single organic electroluminescent device, or may be applied to a configuration in which a plurality of organic electroluminescent devices are arranged in an array. Alternatively, the present invention may be applied to a configuration in which the anode and the cathode are arranged in an XY matrix.
Each layer described above may contain components other than those described as materials unless the effects of the present invention are significantly impaired.

<Organic EL display>
The organic electroluminescent element obtained by the production method of the present invention is used for an organic EL display. The organic electroluminescent device obtained by the present invention is described in, for example, “Organic EL Display” (Ohm, August 20, 2004, written by Shizushi Tokito, Chiba Adachi, and Hideyuki Murata). An organic EL display can be formed by the method.

EXAMPLES Hereinafter, although this invention is demonstrated further in detail using an Example, this invention is not limited to a following example, unless it deviates from the summary.
(Synthesis Example 1)

Toluene (147 ml) and ethanol (147 ml) were added to 1,2-dibromobenzene (21.0 g, 89 mmol) and 3-methoxyphenylboronic acid (29.8 g, 196 mmol) to deaerate the system. Further, tetrakis (triphenylphosphine) palladium (6.17 g, 5.3 mmol) was added, a 2M sodium carbonate aqueous solution (357 g, 587 mmol) that had been degassed in advance was added, and heating reflux was performed for 6 hours. After confirming the disappearance of the raw materials, water was added to the reaction solution, followed by extraction with toluene and liquid separation. The obtained organic layer was washed with water, treated with activated clay, and concentrated. The resulting crude product was purified by silica gel column chromatography (hexane / methylene chloride) to obtain Target 1 (20.44 g, yield 79%).
(Synthesis Example 2)

Methylene chloride (70 ml) was added to the target compound 1 (15.5 g, 53 mmol) obtained in Synthesis Example 1, and concentrated sulfuric acid (1.4 g) was added. The reaction mixture was ice-cooled and anhydrous iron chloride (17.32 g, 107 mmol) was slowly added. After stirring for 3.5 hours, anhydrous iron chloride (4.33 g, 26 mmol) and methylene chloride (20 ml) were further added, and the mixture was slowly returned to room temperature and stirred for 3 hours. The reaction solution was poured into cooled methanol (300 ml), and the resulting crystals were collected by filtration. The obtained crystals were dissolved in methylene chloride (250 ml), washed with 1N aqueous hydrochloric acid, and the organic layer was filtered through Celite and concentrated. The precipitated crystals were washed with methanol to obtain the intended product 2 (7.41 g, yield 48%).
(Synthesis Example 3)

To the target compound 2 (7.41 g, 26 mmol) obtained in Synthesis Example 2, methylene chloride (110 ml) was added, and a 1M boron tribromide methylene chloride solution (65 ml, 65 mmol) was added dropwise under ice-cooling for 4 hours. Stir. Since the disappearance of the raw materials was confirmed, water was added to the reaction solution, extracted with ethyl acetate, and the organic layer was concentrated. The precipitated crystals were washed with a methylene chloride / ethanol (5/1) solution and dried to obtain the desired product 3 (6.58 g, yield 98%).
(Synthesis Example 4)

Methylene chloride (145 ml) was added to the target compound 3 (7.27 g, 27.9 mmol) obtained in Synthesis Example 3, and trifluoromethylsulfonic anhydride (16.55 g, 58.7 mmol) was added. Pyridine (4.64 g, 58.7 mmol) was added dropwise to this solution. Since the raw materials did not completely disappear, trifluoromethylsulfonic anhydride (4.65 g), pyridine (1.35 g), and methylene chloride (150 ml) were added after 4 hours. The mixture was further stirred for 6 hours. The reaction solution is washed with water, concentrated and precipitated crystals are washed with methanol,
The target product 4 (13.6 g, yield 93%) was obtained.
(Synthesis Example 5)

To the target compound 4 (100 mg, 0.191 mmol), 4- (diphenylamino) phenylboronic acid (121 mg, 0.420 mmol) obtained in Synthesis Example 4, toluene (2 ml)
, Ethanol (1 ml) was added, and the inside of the system was deaerated. Further, tetrakis (triphenylphosphine) palladium (11 mg, 0.0096 mmol) was added, a 2M sodium carbonate aqueous solution (0.6 g, 0.959 mmol) that had been degassed in advance was added, and heating reflux was performed for 6 hours. After confirming the disappearance of the raw materials, water was added to the reaction solution, and the mixture was extracted with CH ₂ Cl ₂ and separated. The obtained organic layer was washed with water, treated with activated clay, and concentrated. The resulting crude product was purified by silica gel column chromatography (hexane / methylene chloride) to obtain the desired product 5 (48.9 g) (yield: 35.6%).

¹ H-NMR (CDCl ₃ , 270 MHz): σ 7.03-7.09 (m, 4H), 7.19-7.33 (m, H), 7.66-7.72 (m, 6H), 7.89 (dd, 2H), 8.70 (d, 2H), 8.75 (q, 2H), 8.83 (d, 2H)
Example 1
The target product 5 (0.2 mg) synthesized in Synthesis Example 5 was dissolved in methylene chloride (25 ml), and the fluorescence of the methylene chloride solution was measured using an F4500 type spectrofluorometer (manufactured by Hitachi High-Technologies Corporation). It was measured. In addition, the powder was sandwiched between slide glasses, and the luminescence in the solid state was measured in the same manner.

The measurement results of the fluorescence spectra in the solid state and in the solution state are shown in FIG. 2, and the respective maximum emission wavelengths are shown in Table 1.
As shown in Table 1, it can be seen that even in the solid state, the same fluorescence is emitted as in the solution state.
(Comparative Example 1)
Fluorescence was measured in the same manner as in Example 1 except that Compound 1 represented by the following formula was used as Target 5 in Example 1.

  The measurement results of the fluorescence spectra in the solid state and the solution state are shown in FIG. 3, and the respective maximum emission wavelengths are shown in Table 1.

  As described above, the triphenylene compound of the present invention emits fluorescence at the same emission wavelength as that in the solution state even in the solid state where the intermolecular interaction tends to be strong. It can also be suitably used in an organic device that uses

The triphenylene compound of the present invention emits fluorescence at the same emission wavelength as that in a solution state even in a solid state in which interaction between molecules tends to be strong. Therefore, it can be suitably used for a charge transport material for wet film formation having excellent wet process suitability.
The present invention also relates to various fields where organic electroluminescent elements are used, such as flat panel displays (for example, for OA computers and wall-mounted televisions) and light sources that make use of the characteristics of surface light emitters (for example, copying machines). It can be suitably used in the fields of a light source, a liquid crystal display and a backlight light source for instruments), a display panel, a marker lamp, and the like.

It is sectional drawing which shows typically an example of the structure of the organic electroluminescent element of this invention. 6 is a fluorescence spectrum diagram of the target product 5 obtained in Synthesis Example 5. FIG. The vertical axis represents normalized absorbance, and the vertical axis represents absorbance (nm). 2 is a fluorescence spectrum diagram of Compound 1. FIG. The vertical axis represents normalized absorbance, and the vertical axis represents absorbance (nm).

Explanation of symbols

1 Substrate
2 Anode
3 Hole injection layer
4 hole transport layer
5 Light emitting layer
6 Hole blocking layer
7 Electron transport layer
8 Electron injection layer
9 Cathode

Claims (7)

A triphenylene compound represented by the following formula (4):

(In Formula (4), R < ⁰ > -R < ⁴ > represents a substituent each independently.
a to e each independently represent an integer of 0 or more.
When any of a to e is 2 or more, the plurality of R ^{0 to} R ⁴ contained in one molecule may be the same or different from each other independently. )   A charge transport material comprising the triphenylene compound according to claim 1.   A luminescent material comprising the triphenylene compound according to claim 1.   An organic electroluminescent element composition comprising the triphenylene compound according to claim 1 and a solvent.   An organic electroluminescent device comprising an organic layer formed by a wet film-forming method using the composition for an organic electroluminescent device according to claim 4.   An organic electroluminescent device having an anode, a cathode, and an organic layer provided between the anode and the cathode, wherein the organic layer contains the triphenylene compound according to claim 1, Organic electroluminescent device.   An organic EL display using the organic electroluminescent element according to claim 5.

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