JP4701818B2 - Triazine compound, composition for organic electroluminescence device, and organic electroluminescence device - Google Patents

Description

  The present invention relates to a triazine compound useful as a material for an organic electroluminescence device, a composition for an organic electroluminescence device, and an organic electroluminescence device.

An organic electroluminescence element (hereinafter also referred to as “organic EL element”) can be driven by a DC voltage, is a self-luminous element, has a wide viewing angle and high visibility, and a response speed. Therefore, it is expected as a next-generation display element and has been actively researched.
As such an organic EL element, one having a single layer structure in which a light emitting layer made of an organic material is formed between an anode and a cathode, one having a hole transport layer between the anode and the light emitting layer, A multilayer structure such as one having an electron transport layer between a cathode and a light emitting layer is known. All of these organic EL devices emit light by recombination of electrons injected from the cathode and holes injected from the anode in the light emitting layer.

In an organic EL element, the light emitting layer is required to have high luminous efficiency. Recently, in order to realize high luminous efficiency, an attempt has been made to use energy of triplet state molecules as an excited state for light emission of the organic EL element.
Specifically, according to the organic EL element having such a configuration, it is possible to obtain an external quantum efficiency of 8% exceeding 5% which has been conventionally considered as the limit value of the external quantum efficiency of the organic EL element. Have been reported (for example, see Non-Patent Document 1 and Non-Patent Document 2).
However, this organic EL element is composed of a low molecular weight material, and is formed by a dry method such as a vapor deposition method. For example, this dry method has a limit in forming a layer having a large area. Therefore, there is a problem that it is difficult to apply to, for example, a large-screen display device.

“Applied Physics Letters”, 1999, vol. 75, p. 4 “Chemical Materials”, 2004, Vol. 16, p. 1285

The present invention has been made based on the circumstances as described above, and the object thereof is excellent in solubility in a solvent, can easily form a thin film, and is suitable as a material for an organic electroluminescence element. It is to provide a triazine compound to be used.
Another object of the present invention is to provide a composition for an organic electroluminescence device from which an organic electroluminescence device having excellent light emission characteristics can be obtained, and an organic electroluminescence device.

〔式中、ｎ１〜ｎ６は、それぞれ独立に１〜１９の整数である。〕
このトリアジン化合物は、一般式（１）で表される。
The triazine compound of the present invention is represented by the following general formula (X) .

[Wherein, n1 to n6 each independently represents an integer of 1 to 19. ]
This triazine compound is represented by the general formula (1).

[Wherein, R ¹ and R ² each independently represent a monovalent organic group, and R ³ and R ⁴ each independently represent an aryl group or a heterocyclic group. ]

In the general formula (1) , R ¹ and R ² are each an alkyl group having 1 to 30 carbon atoms, an alkoxyl group having 1 to 30 carbon atoms, an aryl group, a heterocyclic group, or the following general formula (1-A) to A group represented by the following general formula (1-C) is preferable.

[In General Formula (1-A), R ⁵ and R ⁶ each independently represent an alkyl group having 1 to 60 carbon atoms or an alkoxyl group having 1 to 30 carbon atoms. In General Formula (1-B), R ⁷ and R ⁸ each independently represent a hydrogen atom or an alkyl group having 1 to 30 carbon atoms. In General Formula (1-C), R ⁹ and R ¹⁰ each independently represent a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, an aryl group, or a heterocyclic group. ]

  The composition for an organic electroluminescence device of the present invention is characterized by containing a component composed of the above triazine compound and a component composed of a triplet light-emitting metal complex compound.

  The organic electroluminescent device of the present invention is characterized by having a light emitting layer formed of the above-mentioned composition for organic electroluminescent devices.

  The organic electroluminescent element of the present invention preferably comprises a hole block layer.

  The triazine compound of the present invention is useful as a material for an organic electroluminescence device because it is excellent in solubility in a solvent and can easily form a thin film and has good carrier transportability.

  Moreover, according to the composition for organic electroluminescent elements of the present invention, the triplet light-emitting metal complex compound is contained as the first component, and the triazine compound is contained as the second component. Therefore, an organic electroluminescence device having excellent light emission characteristics and durability can be obtained.

  Furthermore, according to the organic electroluminescent element of the present invention, by using the composition for an organic electroluminescent element as a material of the light emitting layer, it is possible to obtain excellent durability as well as excellent light emission characteristics by triplet light emission. it can.

  Hereinafter, embodiments of the present invention will be described in detail.

<Triazine compound>
The triazine compound of the present invention is a triazine compound represented by the above general formula (1) (hereinafter also referred to as “specific triazine compound”), and is useful as a material for an organic electroluminescence device.

In the general formula (1), R ¹ and R ² each independently represent a monovalent organic group, and R ¹ and R ² may be the same or different from each other.

Examples of the monovalent organic group representing the group R ¹ and the group R ² include an alkyl group having 1 to 30 carbon atoms, an alkoxyl group having 1 to 30 carbon atoms, an aryl group, a heterocyclic group, and the above general formula (1- It is preferable that it is group represented by A)-said general formula (1-C).

The aryl group representing the group R ¹ and the group R ² is preferably an unsubstituted group, a group having an alkyl group having 1 to 30 carbon atoms as a substituent, or a cyanophenyl group.
Further, examples of the heterocyclic group represented by R ¹ and groups R ^2, pyridinyl group.

In the general formula (1-A) representing the group R ¹ and the group R ² , R ⁵ and R ⁶ each independently represent an alkyl group having 1 to 60 carbon atoms or an alkoxyl group having 1 to 30 carbon atoms, R ⁵ and R ⁶ may be the same or different from each other, but are preferably the same.

In the general formula (1-B) representing the group R ¹ and the group R ² , R ⁷ and R ⁸ each independently represent a hydrogen atom or an alkyl group having 1 to 30 carbon atoms, and the R ⁷ and R ⁸ are These may be the same or different, but are preferably the same.

In the general formula (1-C) representing the group R ¹ and the group R ² , R ⁹ and R ¹⁰ each independently represent a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, an aryl group, or a heterocyclic group, R ⁹ and R ¹⁰ may be the same or different from each other, but are preferably the same.
Here, the aryl group representing the group R ⁹ and the group R ¹⁰ is preferably a phenyl group, a cyanophenyl group, or an alkylphenyl group.
As the heterocyclic group represents a group R ⁹ and groups R ^10, pyridinyl group.

In the general formula (1), R ³ and R ⁴ each independently represents an aryl group or a heterocyclic group, and these R ³ and R ⁴ may be the same or different from each other. However, they are preferably the same.

Examples of the aryl group a group R ³ and a group R ^4, a phenyl group, a cyanophenyl group, alkyl phenyl group.
As the heterocyclic group represents a group R ³ and a group R ^4, such as pyridinyl group.

The groups R ³ and R ⁴ are preferably bonded to positions 3 and 6 in the carbazole ring or positions 2 and 7 in the carbazole ring, respectively.

Preferred specific examples of the specific triazine compound are compounds represented by the following formula (A-1) to the following formula (A-10), and represented by the following formula (B-1) to the following formula (B-10). Compound, compound represented by formula (C-1) to formula (C-14), compound represented by formula (D-1) to formula (D-10), formula (E-1) ) To the compound represented by the following formula (E-10), the compound represented by the following formula (F-1) to the following formula (F-14), and the following formula (G-1) to the following formula (G-4). ).
Here, the compounds represented by the formula (A-1) to the formula (A-10) and the compounds represented by the formula (B-1) to the formula (B-10) are respectively represented by the general formula (1). R ¹ and R ² are both alkoxyl groups, and are represented by the compounds represented by formula (C-1) to formula (C-14) and formula (D-1) to formula (D-10). In the compound, each of R ¹ and R ² in the general formula (1) is a group represented by the general formula (1-A) or a group represented by the general formula (1-B), In the compounds represented by formula (E-1) to formula (E-10), R ¹ in general formula (1) is a group represented by general formula (1-C), and R ² There are those an alkoxyl group, a compound represented by the formula (F-1) ~ formula (F-14), respectively, R ¹ in the general formula (1) is represented by the general formula (1-C) That a group are those wherein R ² is a group represented by the formula (1-A) groups represented by or the general formula (1-B), also, the formula (G-1) ~ formula ( The compound represented by G-4) is a compound in which R ¹ and R ² in the general formula (1) are both groups represented by the general formula (1-C).

[In Formula (A-1) to Formula (A-10), m1 and m2 are each independently an integer of 1 to 29, and n1 and n2 are each independently an integer of 1 to 19. ]

[In Formula (B-1) to Formula (B-10), m1 and m2 are each independently an integer of 1 to 29, and n1 and n2 are each independently an integer of 1 to 19. ]

[In Formula (C-1) to Formula (C-10), n1 and n2 are each independently an integer of 1 to 19, and p1 and p2 are each independently an integer of 1 to 59. ]

[In Formula (C-11) to Formula (C-14), n1 and n2 are each independently an integer of 1 to 19. ]

[In Formula (D-1) to Formula (D-10), n1 and n2 are each independently an integer of 1 to 19, and p1 and p2 are each independently an integer of 1 to 59. ]

[In Formula (E-1) to Formula (E-8), m1 is each independently an integer of 1 to 29, and n1 to n4 are each independently an integer of 1 to 19. ]

[In Formula (E-9) and Formula (E-10), m1 is an integer of 1 to 29. ]

[In Formula (F-1) to Formula (F-8), n1 to n4 are each independently an integer of 1 to 19, and p1 is an integer of 1 to 59. ]

[In Formula (F-9) to Formula (F-14), n1 to n4 are each independently an integer of 1 to 19, and p1 is an integer of 1 to 59. ]

[In Formula (G-1) to Formula (G-4), n1 to n6 are each independently an integer of 1 to 19. ]

  As shown in the following reaction formula (1), the specific triazine compound is also referred to as, for example, a specific carbazole compound (hereinafter also referred to as “raw carbazole compound”) and a specific triazine compound (hereinafter referred to as “raw triazine compound”). ).

[Wherein, R ¹ and R ² each independently represent a monovalent organic group, R ³ and R ⁴ each independently represent an aryl group or a heterocyclic group, and X ¹ represents a chlorine atom or a bromine atom. Or an iodine atom is shown. ]

The reaction between the raw material carbazole compound and the raw material triazine compound is described, for example, in Chem. Mater. 16, page 1285-1291 (2004).
Specifically, in an inert gas atmosphere, an equivalent amount of an organic metal or the like is reacted with a raw material carbazole compound in a solvent under reaction conditions of, for example, a reaction temperature of −78 to 30 ° C. and a reaction time of 0.1 to 10 hours. Thereafter, a solution in which the raw material triazine compound is dissolved in a solvent is dropped, and the reaction can be performed, for example, under reaction conditions of a reaction temperature of 0 to 80 ° C. and a reaction time of 0.5 to 24 hours.

Here, as a solvent, diethyl ether, tetrahydrofuran, etc. can be used, for example, The usage-amount is 100-10000 mass parts with respect to 100 mass parts of raw material carbazole compounds, for example.
Moreover, as an organic metal, n-butyllithium, s-butyllithium, and t-butyllithium can be used, for example, and the usage-amount is 0.5-1.2 mass with respect to 1 mol of raw material carbazole compounds, for example. Part.

Specifically, in the general formula (1), a specific triazine compound in which R ¹ and R ² are the same alkoxyl group and R ³ and R ⁴ are the same aryl group is represented by the following reaction formula (2). It can manufacture by making the raw material carbazole compound obtained by the reaction process react with the raw material triazine compound obtained by the reaction process shown by following Reaction formula (3).
In the general formula (1), the specific triazine compound in which R ¹ and R ² are groups represented by the same general formula (1-A), and R ³ and R ⁴ are the same aryl group, It can manufacture by making the raw material carbazole compound obtained by the reaction process shown by Reaction formula (2) react with the raw material triazine compound obtained by the reaction process shown by the following reaction formula (4).
In the general formula (1), R ¹ and R ² are groups represented by the same general formula (1-B), and R ³ and R ⁴ are the same aryl group, It can manufacture by making the raw material carbazole compound obtained by the reaction process shown by Reaction formula (2) react with the raw material triazine compound obtained by the reaction process shown by the following reaction formula (5).

[In Reaction Formula (2) to Reaction Formula (5), R ¹¹ represents a hydrogen atom or a monovalent organic group, R ¹³ represents an alkyl group having 1 to 30 carbon atoms, and R ¹⁴ represents 1 to 60 carbon atoms. Or an alkyl group having 1 to 30 carbon atoms, R ¹⁵ represents a hydrogen atom or an alkyl group having 1 to 30 carbon atoms, and X ¹ represents a chlorine atom, a bromine atom or an iodine atom. ]

  Reaction formulas (3) to (5) are described in J. Org. Amer. Chem. Soc. 73, 2981.

  The specific triazine compound can form a film by a dry method such as a vapor deposition method, but it has excellent solubility in a solvent and can easily prepare a coating solution for forming a thin film. Therefore, a thin film can be easily formed with the coating solution. Therefore, the specific triazine compound is useful as a material for an organic EL device.

  In addition, since the specific triazine compound has a good carrier transport property, it can be suitably used as a material constituting the light-emitting layer of the organic EL element by combining with a light-emitting material having phosphorescence, for example. it can.

<Composition for organic EL device>
The composition for an organic EL device of the present invention includes a component composed of the above specific triazine compound (hereinafter also referred to as “triazine component”) and a component composed of a triplet light emitting metal complex compound (hereinafter referred to as “complex component”). And the like)).

  Examples of the triplet light-emitting metal complex compound constituting the complex component include iridium complex compounds, platinum complex compounds, palladium complex compounds, rubidium complex compounds, osmium complex compounds, rhenium complex compounds, etc. Among these, iridium Complex compounds are preferred.

Examples of the iridium complex compound constituting the complex component include iridium, phenylpyridine, phenylpyrimidine, bipyridyl, 1-phenylpyrazole, 2-phenylquinoline, 2-phenylbenzothiazole, 2-phenyl-2-oxazoline, 2,4- A complex compound with a nitrogen atom-containing aromatic compound such as diphenyl-1,3,4-oxadiazole, 5-phenyl-2- (4-pyridyl) -1,3,4-oxadiazole or a derivative thereof; Can be used.
Specific examples of such iridium complex compounds include compounds represented by the following general formula (2) to the following general formula (4).

In the above general formulas (2) to (4), R ¹⁶ and R ¹⁷ each represent a substituent composed of a fluorine atom, an alkyl group or an aryl group, and may be the same or different from each other. May be. x is an integer of 0 to 4, and y is an integer of 0 to 4.

In the above, specific examples of the alkyl group related to the substituents R ¹⁶ and R ¹⁷ include a methyl group, an ethyl group, an isopropyl group, a t-butyl group, an n-butyl group, an isobutyl group, a hexyl group, and an octyl group. be able to.
Specific examples of the aryl group include a phenyl group, a tolyl group, a xylyl group, a biphenyl group, and a naphthyl group.

  Among these, it is particularly preferable to use an iridium complex compound represented by the general formula (2) (hereinafter also referred to as “specific iridium complex compound”).

  This specific iridium complex compound is usually synthesized by reacting a compound represented by the following general formula (5) with a compound represented by the following general formula (6) in the presence of a polar solvent. However, it is important that the content of the specific impurity compound represented by the following general formula (7) generated in that case is 1000 ppm or less.

In General Formula (5) to General Formula (7), R ¹⁶ and R ¹⁷ are the same as those in General Formula (2). x is an integer of 0 to 4, and y is an integer of 0 to 4.

  The specific iridium complex compound in which the content of the specific impurity compound is 1000 ppm or less can be obtained by purifying the reaction product obtained from the synthesis reaction.

  In a specific iridium complex compound, when the content of the specific impurity compound exceeds 1000 ppm, the light emission performance of the specific iridium complex compound is hindered, and thus an organic EL element having high emission luminance is obtained. Becomes difficult.

  It is preferable that the content rate of the complex component in the composition for organic EL elements of this invention is 0.1-30 mass parts with respect to 100 mass parts of triazine components, More preferably, it is 0.5-10 mass parts. . When the content ratio of the complex component is too small, it may be difficult to obtain sufficient light emission. On the other hand, when the ratio of the complex component is excessive, a phenomenon of concentration quenching in which the brightness of light emission decreases instead may occur.

  If necessary, any additive such as a charge transporting compound can be added to the composition for an organic EL device of the present invention.

  As the charge transporting compound, a compound having charge transporting property represented by the following formula (A-1) to the following formula (A-10), represented by the following formula (A-1) to the following formula (A-20). And a compound having a hole transport property represented by the following formula (U-1) to the following formula (U-34).

  Here, in the formula (A-16), Y represents any one of groups represented by the following formulas (a) to (c).

  Here, in formula (C-12), q represents an integer of 1 or more.

  The addition amount of the charge transporting compound in the composition for organic EL devices of the present invention is preferably 0 to 70 mol% with respect to 100 mol% of the triazine component.

  In addition, the organic EL device composition of the present invention has, for example, the following general formula (8) for the purpose of improving the coating properties required when forming a light emitting layer in an organic EL device by the method described later. A polymer such as an arylene ether polymer (hereinafter, also referred to as “specific arylene ether polymer”) composed of the repeating units represented can be added.

[Wherein, R ^{18 to} R ²¹ each independently represents a hydrogen atom, a fluorine atom or a monovalent organic group, and A represents a divalent aromatic group. ]

  The addition amount of the specific arylene ether polymer in the composition for an organic EL device of the present invention is preferably 0 to 70 mol% with respect to 100 mol% of the triazine component.

  The composition for organic EL devices of the present invention is usually prepared as a composition solution by dissolving a triazine component composed of the specific triazine compound and a complex component in an appropriate organic solvent. Then, the composition solution is applied to the surface of the substrate on which the light emitting layer is to be formed, and an organic solvent is removed from the obtained coating film, thereby forming a light emitting layer in the organic EL element. it can.

Here, the organic solvent for preparing the composition solution is not particularly limited as long as it can dissolve the triazine component and the complex component used, and specific examples thereof include anisole, toluene, xylene, mesitylene and the like. Aromatic hydrocarbon solvents, halogenated hydrocarbon solvents such as chloroform, chlorobenzene and tetrachloroethane, amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide and 1-methyl-2-pyrrolidone, Examples include cyclohexanone, ethyl lactate, propylene glycol methyl ether acetate, ethyl ethoxypropionate, and methyl amyl ketone. These organic solvents can be used alone or in combination of two or more.
Among these, it is preferable to use an organic solvent having an appropriate evaporation rate, specifically, an organic solvent having a boiling point of about 70 to 200 ° C. in that a thin film having a uniform thickness can be obtained.

The use ratio of the organic solvent varies depending on the types of the triazine component and the complex component, but is usually such a ratio that the total concentration of the triazine component and the complex component in the composition solution is 0.5 to 10% by mass.
As a means for applying the composition solution, for example, a spin coating method, a dipping method, a roll coating method, an ink jet method, a printing method, or the like can be used.
Although the thickness of the light emitting layer formed is not specifically limited, Usually, 10-200 nm, Preferably it selects in the range of 30-100 nm.

  According to such a composition for an organic EL device, an organic EL device having a light emitting layer that emits light with sufficiently high light emission luminance can be obtained, and the light emitting layer can be easily formed by a wet method such as an inkjet method. can do.

<Organic EL device>
FIG. 1 is an explanatory cross-sectional view showing an example of the configuration of the organic EL element of the present invention.
In the organic EL element of this example, an anode 2 as an electrode for supplying holes is provided on a transparent substrate 1 by, for example, a transparent conductive film, and a hole injecting and transporting layer 3 is provided on the anode 2. A light emitting layer 4 is provided on the hole injection transport layer 3, a hole block layer 8 is provided on the light emitting layer 4, an electron injection layer 5 is provided on the hole block layer 8, and the electron injection layer 5 is provided on the hole injection layer 5. A cathode 6 which is an electrode for supplying electrons is provided. The anode 2 and the cathode 6 are electrically connected to a DC power source 7.

In this organic EL element, as the transparent substrate 1, a glass substrate, a transparent resin substrate, a quartz glass substrate, or the like can be used.
As a material constituting the anode 2, a transparent material having a high work function, for example, 4 eV or more is preferably used. Here, the work function refers to the minimum work required to extract electrons from a solid in a vacuum. For example, an ITO (Indium Tin Oxide) film, a tin oxide (SnO ₂ ) film, a copper oxide (CuO) film, or a zinc oxide (ZnO) film can be used as the anode 2.

  The hole injection transport layer 3 is provided to efficiently supply holes to the light emitting layer 4 and has a function of receiving holes from the anode 2 and transporting them to the light emitting layer 4. Is. As a material constituting the hole injecting and transporting layer 3, for example, a charge injecting and transporting material such as poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate can be suitably used. Moreover, the thickness of the hole injection transport layer 3 is, for example, 10 to 200 nm.

  The light emitting layer 4 has a function of combining electrons and holes and emitting the binding energy as light, and the light emitting layer 4 is formed of the above-described composition for organic EL elements. Although the thickness of the light emitting layer 4 is not specifically limited, Usually, it selects in the range of 5-200 nm.

  The hole blocking layer 8 suppresses intrusion of holes supplied to the light emitting layer 4 through the hole injecting and transporting layer 3 into the electron injecting layer 5, and recombines holes and electrons in the light emitting layer 4. It has a function of promoting and improving luminous efficiency.

Examples of the material constituting the hole blocking layer 8 include 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (basocproin: BCP) represented by the following formula (1), and the following formula (2). 1,3,5-tri (phenyl-2-benzimidazolyl) benzene (TPBI) represented by the formula can be preferably used.
Moreover, the thickness of the hole block layer 8 is 10-30 nm, for example.

  The electron injection layer 5 has a function of transporting electrons received from the cathode 6 to the light emitting layer 4 through the hole blocking layer 8. As a material constituting the electron injection layer 5, it is preferable to use a co-evaporation system (BPCs) of a bathophenanthroline-based material and cesium, and as other materials, an alkali metal and a compound thereof (for example, lithium fluoride, oxide) Lithium), alkaline earth metals and compounds thereof (eg, magnesium fluoride, strontium fluoride), and the like can be used. The thickness of this electron injection layer 5 is, for example, 0.1 to 100 nm.

As a material constituting the cathode 6, a material having a small work function, for example, 4 eV or less is used. As a specific example of the cathode 6, a metal film made of aluminum, calcium, magnesium, indium, or the like, or an alloy film of these metals can be used.
Although the thickness of the cathode 6 changes with kinds of material, it is 10-1000 nm normally, Preferably it is 50-200 nm.

In the present invention, the organic EL element is manufactured as follows, for example.
First, the anode 2 is formed on the transparent substrate 1.
As a method of forming the anode 2, a vacuum deposition method, a sputtering method, or the like can be used. A commercially available material in which a transparent conductive film such as an ITO film is formed on the surface of a transparent substrate such as a glass substrate can also be used.

A hole injection transport layer 3 is formed on the anode 2 thus formed.
As a method for forming the hole injection transport layer 3, specifically, a hole injection transport layer forming liquid is prepared by dissolving the charge injection transport material in an appropriate solvent. A method of forming the hole injection transport layer 3 by applying to the surface of the anode 2 and subjecting the obtained coating film to solvent removal treatment can be used.

Next, the composition for organic EL device of the present invention is used as a light emitting layer forming liquid, this light emitting layer forming liquid is applied onto the hole injecting and transporting layer 3, and the obtained coating film is heat-treated, whereby the light emitting layer 4 Form.
As a method for applying the light emitting layer forming liquid, a spin coating method, a dip method, an ink jet method, a printing method, or the like can be used.

  Then, a hole blocking layer 8 is formed on the light emitting layer 4 thus formed, an electron injection layer 5 is formed on the hole blocking layer 8, and further on the electron injection layer 5. By forming the cathode 6, an organic EL element having the configuration shown in FIG. 1 can be obtained.

  In the above, as a method of forming the hole block layer 8, the electron injection layer 5, and the cathode 6, a dry method such as a vacuum evaporation method can be used.

In the above organic EL element, when a DC voltage is applied between the anode 2 and the cathode 6 by the DC power source 7, the light emitting layer 4 emits light, and this light is emitted from the hole injection transport layer 3, the anode 2. Then, the light is emitted to the outside through the transparent substrate 1.
According to the organic EL element having such a configuration, since the light emitting layer 4 is formed of the above-described composition for an organic EL element, high light emission luminance and light emission efficiency can be obtained.

  Further, since the hole blocking layer 8 is provided, the coupling between the holes from the anode 2 and the electrons from the cathode 2 is realized with high efficiency, and as a result, high light emission luminance and light emission efficiency can be obtained.

  Specific examples of the present invention will be described below, but the present invention is not limited to these examples.

[Example 1]
<Synthesis Example 1 of Specific Triazine Compound>
A three-necked flask with a volume of 500 ml was charged with 25 g of 1-bromo-4-n-octylbenzene, degassed and then purged with nitrogen, added with 200 ml of tetrahydrofuran and stirred, and the reaction system was cooled in a dry ice-acetone bath. After that, 66 ml of n-butyllithium hexane solution having a concentration of 1.56 mol / L was added and stirred for 2 hours, and then 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane. 19.0 g was added.
The obtained reaction solution was gradually returned to room temperature and further stirred for 24 hours, and then the reaction solution was transferred to a separatory funnel and shaken vigorously to obtain an organic phase. The obtained organic phase was washed with 300 ml of saturated brine, dried over anhydrous magnesium sulfate for 30 minutes, concentrated with an evaporator, and then purified with a silica gel-hexane column to obtain the following formula (3). 26.4 g of 2- (4-n-octylphenyl) -4,4,5,5-tetramethyl-1,3,2-dioxaborolane (hereinafter also referred to as “intermediate product (1)”) shown in FIG. Got. When the purity of this intermediate product (1) was confirmed by HPLC (high performance liquid chromatography), it was 100%.

  In a three-necked flask with a volume of 200 ml, 14.6 g of intermediate product (1), 5.0 g of 3,6-dibromocarbazole, 0.138 g of palladium acetate, 0.184 g of di- (t-butylphosphino) biphenyl, Then, 5.36 g of potassium fluoride was added, and after deaeration treatment, nitrogen substitution treatment was performed, 62 ml of tetrahydrofuran was added and stirred for 12 hours under reflux, and the resulting reaction solution was transferred to a separatory funnel. Inside, 300 ml of ethyl acetate and 200 ml of pure water were added and shaken to obtain an organic phase. The obtained organic phase was washed with 200 ml of saturated brine, dried over anhydrous magnesium sulfate for 30 minutes, concentrated with an evaporator, and then purified with a silica gel-hexane column to obtain the following formula (4). As a result, 8.0 g of 3,6-di (4-n-octylphenyl) carbazole (hereinafter also referred to as “intermediate product (2)”) was obtained. When the purity of this intermediate product (2) was confirmed by HPLC, it was 100%.

A three-necked flask with a volume of 200 ml was charged with 5.0 g of the intermediate product (2), degassed and then purged with nitrogen, added with 92 ml of tetrahydrofuran, and the reaction system was cooled to −78 ° C. in a dry ice-acetone bath. Thereafter, 5.9 ml of an n-butyllithium hexane solution having a concentration of 1.56 mol / L was added dropwise and stirred for 2 hours, and then a 24.5 ml tetrahydrofuran solution containing 0.45 g of cyanuric chloride was added dropwise and further stirred for 1 hour.
The obtained reaction solution is returned to room temperature, and heated and stirred under reflux for 4 hours. The reaction solution is transferred to a separating funnel, and 300 ml of chloroform and 200 ml of ultrapure water are added to the separating funnel and shaken. The organic phase was obtained. The obtained organic phase was washed with 200 ml of saturated brine, dried over anhydrous magnesium sulfate for 30 minutes, concentrated with an evaporator, and then purified with a silica gel-hexane column to obtain the following formula (5). 2,4,6-tris (3,6-di (4-n-octylphenyl) carbazol-9-yl) -1,3,5-triazine (hereinafter also referred to as “triazine compound (1)”) .) 4.0 g was obtained. When the purity of the triazine compound (1) was confirmed by HPLC, it was 100%.

Further, the HOMO energy level E _H of the triazine compound (1) was measured by using a powder of the triazine compound (1) as a sample and using a photoelectron spectrometer “AC-2” (manufactured by Riken Keiki Co., Ltd.). However, it was −5.79 eV.
Furthermore, the LUMO energy level E _L of the triazine compound (1) was calculated by the following formula (I) and found to be −2.48 eV.
In the formula (I), _EG is an energy gap (unit: eV) calculated from the following formula (II).
In the formula (II), h is a Planck constant, c is the speed of light (unit: m / sec), and λl is a triazine compound (1) on a quartz substrate with a solvent (specifically, A polymer solution dissolved in cyclohexanone) was applied by a spin coating method, and the obtained coating film was heated by a hot plate at 150 ° C. for 10 minutes to remove the solvent, and a thin film having a thickness of 20 to 50 nm was laminated. It is the absorption edge (unit: nm) of the long wavelength side of the absorption spectrum which measured the measurement board | substrate with the ultraviolet visible spectrophotometer "U-2010" (made by Hitachi, Ltd.).

(Formula I) E _L = E _H + E _G

(Formula II) E _G = hc / λl

<Examples of organic EL device production>
An ITO substrate in which an ITO film is formed on a transparent substrate is prepared, and this ITO substrate is ultrasonically cleaned using a neutral detergent, ultrapure water, isopropyl alcohol, ultrapure water, and acetone in this order, and further UV-ozone (UV / O ₃ ) cleaning was performed.
A poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS) solution was applied onto the cleaned ITO substrate by a spin coating method, and then the obtained coating film with a thickness of 65 nm was applied to nitrogen. A hole injection transport layer was formed by drying at 250 ° C. for 30 minutes in an atmosphere.

Next, on the surface of the obtained hole injecting and transporting layer, a specific layer having a number average molecular weight of 7000 consisting of 1.0 g of a triazine compound (1) and a repeating unit represented by the following formula (6) as a light emitting layer forming liquid. 1.0 g of an arylene ether polymer (hereinafter also referred to as “arylene ether polymer (1)”) and 6 mol% of an iridium complex in which x is 0 and y is 0 in general formula (2) are dissolved in anisole. The composition solution for organic EL elements (hereinafter, also referred to as “composition solution (1)”) comprising the composition solution having a concentration of 3% by mass obtained by the above method was applied by spin coating, and the resulting thickness was 40 nm. The coating film was dried at 150 ° C. for 10 minutes in a nitrogen atmosphere to form a light emitting layer.
Next, the laminate in which the hole injecting and transporting layer and the light emitting layer are laminated in this order on the ITO substrate is fixed in a vacuum device, and then the pressure in the vacuum device is reduced to 1 × 10 ⁻⁴ Pa or less. 1,3,5-tri (phenyl-2-benzimidazolyl) benzene (TPBI) was deposited in a thickness of 30 nm to form a hole blocking layer made of a TPBI film. Next, after forming an electron injection layer made of lithium fluoride film by depositing 0.5 nm of lithium fluoride, a cathode made of calcium / aluminum film is formed by depositing calcium 30 nm and aluminum 100 nm in this order. did. Then, the organic EL element (henceforth "organic EL element (1)") was manufactured by sealing with glass material.

(Characteristic evaluation of organic EL elements)
When the light emitting layer was made to emit light with the ITO film as the anode and the calcium / aluminum film as the cathode, the organic EL element (1) was derived from a specific iridium complex. Light emission with a wavelength of around 515 nm was obtained.
Moreover, about the organic EL element (1), the light emitting layer was made to light-emit, and the maximum light-emission luminance and luminous efficiency were measured. The results are shown in Table 1.

[Example 2]
In the preparation example of the organic EL device of Example 1, the charge transporting compound represented by the formula (A-4) is 30 mol with respect to the carbazole group of the triazine compound (1) with respect to the composition solution (1). % Organic EL element (hereinafter referred to as “organic EL element (2)”) in the same manner as in Example 1 except that an organic EL element composition solution consisting of an additive added as an optional component was used. .) Was manufactured.

(Characteristic evaluation of organic EL elements)
With respect to the obtained organic EL element (2), the maximum light emission luminance and light emission efficiency were measured by the same method as in Example 1. The results are shown in Table 1.

It is sectional drawing for description which shows an example of a structure of the organic electroluminescent element of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent substrate 2 Anode 3 Hole injection transport layer 4 Light emitting layer 5 Electron injection layer 6 Cathode 7 DC power supply 8 Hole block layer

Claims (4)

A triazine compound represented by the following general formula (X):

[Wherein, n1 to n6 each independently represents an integer of 1 to 19. ] An organic electroluminescent device composition comprising: a component comprising the triazine compound according to claim 1; and a component comprising a triplet light-emitting metal complex compound . It has a light emitting layer formed with the composition for organic electroluminescent elements of Claim 2, The organic electroluminescent element characterized by the above-mentioned . The organic electroluminescence device according to claim 3, further comprising a hole blocking layer .

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