JP2006080419A - Light emitting element containing iridium complex - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an iridium complex having an excellent color purity, external quantitative efficiency and light emitting efficiency, and an organic EL element using the same. <P>SOLUTION: In a light emitting element formed with a light emitting layer or a plurality of organic compound thin layers containing the light emitting layer between a pair of electrodes, at least one layer is a layer containing at least a kind of iridium complex by a general formula (1). In the above formula, R<SP>1</SP>to R<SP>8</SP>independently represent a hydrogen atom or a substituent, respectively. R<SP>1</SP>and R<SP>2</SP>, R<SP>2</SP>and R<SP>3</SP>, and R<SP>3</SP>and R<SP>4</SP>may be coupled to each other, respectively, to form a fused ring. R<SP>9</SP>and R<SP>10</SP>independently represent alkyl group, aryl group or hetero-aryl group, respectively. n<SP>1</SP>represents an integer of 1 or 2, n<SP>2</SP>is equal to 2 when n<SP>1</SP>is equal to 1, and n<SP>2</SP>is equal to 1 when n<SP>1</SP>is equal to 2. L represents a monovalent anionic ligand. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an iridium complex and a light emitting device using the same. Specifically, the present invention relates to a light-emitting element using an iridium complex that can be suitably used for a display element, a display, a backlight, electrophotography, an illumination light source, a recording light source, an exposure light source, a reading light source, a sign, a signboard, an interior, and the like.

Research and development related to various display elements are active today, and organic electroluminescent elements (hereinafter abbreviated as “organic EL elements”) are particularly promising because they can emit light with high luminance at a low voltage. It is attracting attention as a display element for the next generation. Organic EL elements have a faster response speed than conventional liquid crystals and are self-luminous elements, so they do not require a backlight like conventional liquid crystal display elements, and are extremely thin flat panel displays. Can be formed. Such an organic EL element is a light emitting device utilizing an electroluminescence phenomenon (EL), and is theoretically the same as an LED, but is characterized in that an organic compound is used as a light emitting material. As an example of an organic EL device using such an organic compound as a light emitting material, an organic EL device using a multilayer thin film by a vapor deposition method has been reported. This light-emitting element uses tris (8-hydroxyquinolinato-O, N) aluminum (Alq ₃ ) as an electron transport material, and is stacked with a hole transport material (for example, an aromatic amine compound) to form a conventional single element. The light emission characteristics are greatly improved as compared to the layer type element.

  By the way, in recent years, the movement to apply such an organic EL element to a multi-color display has been actively studied. However, in order to develop a high-performance multi-color display, red, green, and three primary colors of light are used. It is necessary to improve the characteristics and light emission efficiency of each blue light emitting element. As a means for improving the characteristics of the light emitting device, it has been proposed to use a phosphorescent material for the light emitting layer of the organic EL device. Phosphorescence is a light emission phenomenon from a triplet excited state caused by a non-radiative transition called intersystem crossing from a singlet excited state, and exhibits a higher quantum efficiency than fluorescent light emission that is a light emission phenomenon from a singlet excited state. It has been known. It is expected that high luminous efficiency can be achieved by using an organic compound exhibiting such properties as a light emitting material.

As an organic EL element using such a phosphorescent material, tris (2-phenylpyridinato-N, C ^{2 ′} ) iridium (Ir (ppy) ₃ ), which is an orthometalated iridium complex, is used as a light emitting layer. The elements used have been reported. According to this report, it has been found that this iridium complex is a green phosphorescent material having high color purity and an extremely good value of 9% in external quantum efficiency. In recent years, devices using bis [2- (2′-benzothienyl) pyridinato-N, C ^{3 ′} ] iridium acetylacetonate (Ir (btp) ₂ (acac)) as a light emitting layer have been reported (for example, Non-Patent Document 1). Although this iridium complex shows a relatively good value of about 7% in external quantum efficiency, it is not satisfactory in color purity. Furthermore, a compound that emits red to orange light by introducing an arylamino group has also been proposed (see, for example, Patent Document 1). However, when the ligand is bonded to this iridium complex, the ligand is limited to phenylpyridine, thiophenylpyridine, furanylpyridine, and selenopyridines, and characteristics as an organic EL element are unknown.

  As described above, various studies have been actively conducted for the practical application of next-generation display elements. Among them, organic EL elements using phosphorescent materials are particularly in the spotlight from the viewpoint of improving the characteristics of the elements. Yes. However, the research has only just begun, and there are many problems such as optimization of light emission characteristics, light emission efficiency, color purity and structure of the device. In order to solve these problems, development of a novel phosphorescent material and further development of an efficient supply method of the material are desired.

C. Adachi et al., “Appl. Phys. Lett.”, Vol. 78, No. 11, 2001, pages 1622-1624. WO 02/081488

  The present invention has been made in view of the above problems, and it is an object of the present invention to provide a light-emitting element having good light-emitting characteristics and light-emitting efficiency, which can be used in various fields, characterized by containing one or more iridium complexes. And

As a result of intensive studies to solve the above problems, the present inventors have found that an iridium complex having a specific structure and a light emitting device using the same have excellent light emission characteristics and light emission efficiency. Was completed.
That is, the present invention includes the following contents [1] to [6].
[1] In a light emitting device in which a light emitting layer or a plurality of organic compound thin layers including a light emitting layer is formed between a pair of electrodes, at least one layer contains at least one iridium complex represented by the following general formula (1) A light emitting element characterized by the above.

（式中、Ｒ¹〜Ｒ^８は、夫々独立して、水素原子または置換基を表す。但しＲ^１とＲ²、Ｒ²とＲ³、Ｒ³とＲ⁴はそれぞれ結合して環を形成してもよく、該環はさらに結合して縮合環を形成してもよい。Ｒ^５〜Ｒ^８の内、少なくとも一つはＮＲ^９Ｒ^１０の構造をもつ置換基で置換されており、Ｒ^５がＮＲ^９Ｒ^１０で置換されている場合はＲ^６とＲ^７、Ｒ^７とＲ^８はそれぞれ結合して環を形成してもよく、該環はさらに結合して縮合環を形成してもよい。Ｒ^６がＮＲ^９Ｒ^１０で置換されている場合はＲ^４とＲ^５、Ｒ^７とＲ^８はそれぞれ結合して環を形成してもよく、該環はさらに結合して縮合環を形成してもよい。Ｒ^７がＮＲ^９Ｒ^１０で置換されている場合はＲ^４とＲ^５、Ｒ^５とＲ^６はそれぞれ結合して環を形成してもよく、該環はさらに結合して縮合環を形成してもよい。Ｒ^８がＮＲ^９Ｒ^１０で置換されている場合はＲ^４とＲ^５、Ｒ^５とＲ^６、Ｒ^６とＲ^７はそれぞれ結合して環を形成してもよく、該環はさらに結合して縮合環を形成してもよい。Ｒ^９及びＲ^１０は、各々独立して、アルキル基、アリール基、ヘテロアリール基を表す。ｎ^１は１又は２の整数を表し、ｎ^２はｎ^１が１のとき２であり、ｎ^１が２のとき１である。Ｌは一価のアニオン性配位子を表す。）
[２] イリジウム錯体が下記一般式（２）又は（３）で表される錯体である[１]に記載の発光素子。

(In the formula, R ^{1 to} R ⁸ each independently represents a hydrogen atom or a substituent. However, R ¹ and R ² , R ² and R ³ , R ³ and R ⁴ are bonded to form a ring. The ring may be further bonded to form a condensed ring, and at least one of R ^{5 to} R ⁸ is substituted with a substituent having the structure of NR ⁹ R ¹⁰ , ^{When 5} is substituted with NR ⁹ R ¹⁰ , R ⁶ and R ⁷ , R ⁷ and R ⁸ may be bonded to form a ring, and the ring is further bonded to form a condensed ring. When R ⁶ is substituted with NR ⁹ R ¹⁰ , R ⁴ and R ⁵ , R ⁷ and R ⁸ may be bonded to form a ring, and the ring is further bonded to form a condensed ring. good .R ⁷ be formed is if it is substituted with ^NR 9 ^{R 10} forms a ring each ^{R 4} and ^R 5, ^{R 5} and ^{R 6} Well, the ring further when bound to good .R ⁸ also form a condensed ring is substituted with ^NR 9 ^{R 10} is ^{R 4} and ^R 5, ^{R 5} and ^R 6, ^{R 6} and ^{R 7} R ⁹ and R ¹⁰ each independently represents an alkyl group, an aryl group, or a heteroaryl group, which may be bonded to each other to form a ring, which may be further bonded to form a condensed ring. N ¹ represents an integer of 1 or 2, n ² is ² when n ¹ is 1, and 1 when n ¹ is 2. L represents a monovalent anionic ligand.)
[2] The light emitting device according to [1], wherein the iridium complex is a complex represented by the following general formula (2) or (3).

（式（２）及び（３）中、Ｒ^１１及びＲ^１２は、各々独立して、炭素数１〜４のアルキル基で置換されていてもよいフェニル基を表すか、ＮＲ^１１Ｒ^１２でカルバゾリル基を表す。Ｒ^１３はフェニル基又はトリフルオロメチル基を表し、ｎ^３は０、１又は２の整数を表す。Ｑはアセチルアセトナート又はピコリナートを表す。）
[３] 少なくとも一層に含有されるイリジウム錯体が、有機電界発光素子の発光層におけるドーピング材料として作用し得るものである[１]又は[２]のいずれかに記載の発光素子。
[４] 前記発光材料を含有する層が、塗布プロセスで成膜されている[１]〜[３]のいずれかに記載の発光素子。
[５] 下記一般式（１）で表されるイリジウム錯体。

(In formulas (2) and (3), R ¹¹ and R ¹² each independently represent a phenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, or carbazolyl with NR ¹¹ R ¹² . R ¹³ represents a phenyl group or a trifluoromethyl group, n ³ represents an integer of 0, 1 or 2. Q represents acetylacetonate or picolinate.
[3] The light emitting device according to any one of [1] or [2], wherein the iridium complex contained in at least one layer can act as a doping material in the light emitting layer of the organic electroluminescent device.
[4] The light emitting device according to any one of [1] to [3], wherein the layer containing the light emitting material is formed by a coating process.
[5] An iridium complex represented by the following general formula (1).

（式中、Ｒ¹〜Ｒ^８は、夫々独立して、水素原子または置換基を表す。但しＲ^１とＲ²、Ｒ²とＲ³、Ｒ³とＲ⁴はそれぞれ結合して環を形成してもよく、該環はさらに結合して縮合環を形成してもよい。Ｒ^５〜Ｒ^８の内、少なくとも一つはＮＲ^９Ｒ^１０の構造をもつ置換基で置換されており、Ｒ^５がＮＲ^９Ｒ^１０で置換されている場合はＲ^６とＲ^７、Ｒ^７とＲ^８はそれぞれ結合して環を形成してもよく、該環はさらに結合して縮合環を形成してもよい。Ｒ^６がＮＲ^９Ｒ^１０で置換されている場合はＲ^４とＲ^５、Ｒ^７とＲ^８はそれぞれ結合して環を形成してもよく、該環はさらに結合して縮合環を形成してもよい。Ｒ^７がＮＲ^９Ｒ^１０で置換されている場合はＲ^４とＲ^５、Ｒ^５とＲ^６はそれぞれ結合して環を形成してもよく、該環はさらに結合して縮合環を形成してもよい。Ｒ^８がＮＲ^９Ｒ^１０で置換されている場合はＲ^４とＲ^５、Ｒ^５とＲ^６、Ｒ^６とＲ^７はそれぞれ結合して環を形成してもよく、該環はさらに結合して縮合環を形成してもよい。Ｒ^９及びＲ^１０は、各々独立して、アルキル基、アリール基、ヘテロアリール基を表す。ｎ^１は１又は２の整数を表し、ｎ^２はｎ^１が１のとき２であり、ｎ^１が２のとき１である。Ｌは一価のアニオン性配位子を表す。）
[６] 下記一般式（２）又は一般式（３）で表されるイリジウム錯体。

(In the formula, R ^{1 to} R ⁸ each independently represents a hydrogen atom or a substituent. However, R ¹ and R ² , R ² and R ³ , R ³ and R ⁴ are bonded to form a ring. The ring may be further bonded to form a condensed ring, and at least one of R ^{5 to} R ⁸ is substituted with a substituent having the structure of NR ⁹ R ¹⁰ , ^{When 5} is substituted with NR ⁹ R ¹⁰ , R ⁶ and R ⁷ , R ⁷ and R ⁸ may be bonded to form a ring, and the ring is further bonded to form a condensed ring. When R ⁶ is substituted with NR ⁹ R ¹⁰ , R ⁴ and R ⁵ , R ⁷ and R ⁸ may be bonded to form a ring, and the ring is further bonded to form a condensed ring. good .R ⁷ be formed is if it is substituted with ^NR 9 ^{R 10} forms a ring each ^{R 4} and ^R 5, ^{R 5} and ^{R 6} Well, the ring further when bound to good .R ⁸ also form a condensed ring is substituted with ^NR 9 ^{R 10} is ^{R 4} and ^R 5, ^{R 5} and ^R 6, ^{R 6} and ^{R 7} R ⁹ and R ¹⁰ each independently represents an alkyl group, an aryl group, or a heteroaryl group, which may be bonded to each other to form a ring, which may be further bonded to form a condensed ring. N ¹ represents an integer of 1 or 2, n ² is ² when n ¹ is 1, and 1 when n ¹ is 2. L represents a monovalent anionic ligand.)
[6] An iridium complex represented by the following general formula (2) or general formula (3).

（式（２）及び（３）中、Ｒ^１１及びＲ^１２は、各々独立して、炭素数１〜４のアルキル基で置換されていてもよいフェニル基を表すか、ＮＲ^１１Ｒ^１２でカルバゾリル基を表す。Ｒ^１３はフェニル基又はトリフルオロメチル基を表し、ｎ^３は０、１又は２の整数を表す。Ｑはアセチルアセトナート又はピコリナートを表す。）

(In formulas (2) and (3), R ¹¹ and R ¹² each independently represent a phenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, or carbazolyl with NR ¹¹ R ¹² . R ¹³ represents a phenyl group or a trifluoromethyl group, n ³ represents an integer of 0, 1 or 2. Q represents acetylacetonate or picolinate.

  The light-emitting element containing the iridium complex of the present invention can produce an EL element having high light emission characteristics, high light emission efficiency, high durability, and high carrier mobility.

The present invention will be described below.
In the iridium complex used in the light emitting device of the present invention, the substituents represented by R ^{1 to} R ⁸ include a hydrocarbon group, an aliphatic heterocyclic group, an aromatic heterocyclic group, a hydroxyl group, an alkoxy group, and an alkylene group. Oxy, aryloxy, aralkyloxy, heteroaryloxy, acyloxy, acyl, carboxyl, alkoxycarbonyl, aryloxycarbonyl, aralkyloxycarbonyl, mercapto, alkylthio, arylthio, aralkylthio Group, heteroarylthio group, sulfino group, sulfinyl group, sulfo group, sulfonyl group, ureido group, substituted ureido group, silyl group, hydrazino group, cyano group, nitro group, hydroxamic acid group, halogen atom and the like.

  The substituent will be described more specifically. Examples of the hydrocarbon group include an alkyl group, an alkenyl group, an alkynyl group, an aryl group, and an aralkyl group. Among these, the alkyl group may be linear, branched or cyclic, and examples thereof include an alkyl group having 1 to 15 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms. Specifically, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, 2-butyl group, isobutyl group, tert-butyl group, n-pentyl group, 2-pentyl group, tert-pentyl Group, 2-methylbutyl group, 3-methylbutyl group, 2,2-dimethylpropyl group, n-hexyl group, 2-hexyl group, 3-hexyl group, tert-hexyl group, 2-methylpentyl group, 3-methylpentyl Group, 4-methylpentyl group, 2-methylpentan-3-yl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group and the like.

  The alkenyl group may be linear or branched, for example, an alkenyl group having 2 to 15 carbon atoms, preferably 2 to 10 carbon atoms, more preferably 2 to 6 carbon atoms, specifically an ethenyl group. , Propenyl group, 1-butenyl group, pentenyl group, hexenyl group and the like. The alkynyl group may be linear or branched, for example, an alkynyl group having 2 to 15 carbon atoms, preferably 2 to 10 carbon atoms, more preferably 2 to 6 carbon atoms, specifically an ethynyl group. 1-propynyl group, 2-propynyl group, 1-butynyl group, 3-butynyl group, pentynyl group, hexynyl group and the like.

  As an aryl group, a C6-C14 aryl group is mentioned, for example, Specifically, a phenyl group, a naphthyl group, an anthryl group, a phenanthrenyl group, a biphenyl group etc. are mentioned. Examples of the aralkyl group include a group in which at least one hydrogen atom of the alkyl group is substituted with the aryl group. For example, an aralkyl group having 7 to 13 carbon atoms is preferable, specifically, a benzyl group, 2-phenyl An ethyl group, 1-phenylpropyl group, 3-naphthylpropyl group, etc. are mentioned.

  Examples of the aliphatic heterocyclic group include 2 to 14 carbon atoms and at least one hetero atom, preferably 1 to 3 hetero atoms such as a nitrogen atom, an oxygen atom, and a sulfur atom. Examples thereof include an 8-membered, preferably 5- or 6-membered monocyclic aliphatic heterocyclic group, and a polycyclic or condensed aliphatic heterocyclic group. Specific examples of the aliphatic heterocyclic group include pyrrolidyl-2-one group, piperidino group, piperazinyl group, morpholino group, tetrahydrofuryl group, tetrahydropyranyl group, tetrahydrothienyl group and the like.

  The aromatic heterocyclic group (heteroaryl group) has, for example, 2 to 15 carbon atoms and includes at least one, preferably 1 to 3 hetero atoms such as nitrogen, oxygen and sulfur atoms as hetero atoms. A 5- to 8-membered, preferably 5- or 6-membered monocyclic aromatic heterocyclic group, a polycyclic or condensed aromatic heterocyclic group, specifically, a furyl group, a thienyl group, Pyridyl group, pyrimidyl group, pyrazyl group, pyridazyl group, pyrazolyl group, imidazolyl group, oxazolyl group, thiazolyl group, benzofuryl group, benzothienyl group, quinolyl group, isoquinolyl group, quinoxalyl group, phthalazyl group, quinazolyl group, naphthyridyl group, cinnolyl Group, benzoimidazolyl group, benzoxazolyl group, benzothiazolyl group and the like.

  Examples of the alkoxy group may be linear, branched or cyclic, and examples thereof include an alkoxy group having 1 to 6 carbon atoms, specifically, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, n -Butoxy group, 2-butoxy group, isobutoxy group, tert-butoxy group, n-pentyloxy group, 2-methylbutoxy group, 3-methylbutoxy group, 2,2-dimethylpropyloxy group, n-hexyloxy group, A 2-methylpentyloxy group, a 3-methylpentyloxy group, a 4-methylpentyloxy group, a 5-methylpentyloxy group, a cyclohexyloxy group, and the like can be given.

As an alkylene dioxy group, a C1-C3 alkylene dioxy group is mentioned, for example, A methylene dioxy group, an ethylene dioxy group, a propylene dioxy group etc. are mentioned specifically ,.
Examples of the aryloxy group include an aryloxy group having 6 to 14 carbon atoms, and specific examples include a phenyloxy group, a naphthyloxy group, and an anthryloxy group.

Examples of the aralkyloxy group include aralkyloxy groups having 7 to 12 carbon atoms, and specifically include benzyloxy group, 2-phenylethoxy group, 1-phenylpropoxy group, 2-phenylpropoxy group, and 3-phenylpropoxy group. Group, 1-phenylbutoxy group, 2-phenylbutoxy group, 3-phenylbutoxy group, 4-phenylbutoxy group, 1-phenylpentyloxy group, 2-phenylpentyloxy group, 3-phenylpentyloxy group, 4-phenyl Pentyloxy group, 5-phenylpentyloxy group, 1-phenylhexyloxy group, 2-phenylhexyloxy group, 3-phenylhexyloxy group, 4-phenylhexyloxy group, 5-phenylhexyloxy group, 6-phenylhexyl An oxy group etc. are mentioned.
As the heteroaryloxy group, for example, a heteroaryloxy group having 2 to 14 carbon atoms containing at least 1, preferably 1 to 3 hetero atoms such as nitrogen atom, oxygen atom, sulfur atom and the like as hetero atoms. Specifically, 2-pyridyloxy group, 2-pyrazyloxy group, 2-pyrimidyloxy group, 2-quinolyloxy group and the like can be mentioned.

  The acyl group may be linear or branched, and examples thereof include C1-C18 acyl groups derived from carboxylic acids such as aliphatic carboxylic acids and aromatic carboxylic acids. Group, propionyl group, butyryl group, pivaloyl group, pentanoyl group, hexanoyl group, lauroyl group, stearoyl group, benzoyl group and the like.

  The alkoxycarbonyl group may be linear, branched or cyclic, and examples thereof include an alkoxycarbonyl group having 2 to 19 carbon atoms, specifically, a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, 2-propoxycarbonyl group, n-butoxycarbonyl group, tert-butoxycarbonyl group, pentyloxycarbonyl group, hexyloxycarbonyl group, 2-ethylhexyloxycarbonyl group, lauryloxycarbonyl group, stearyloxycarbonyl group, cyclohexyloxycarbonyl group, etc. Is mentioned.

  Examples of the aryloxycarbonyl group include an aryloxycarbonyl group having 7 to 20 carbon atoms, and specific examples include a phenoxycarbonyl group and a naphthyloxycarbonyl group. Examples of the aralkyloxycarbonyl group include an aralkyloxycarbonyl group having 8 to 15 carbon atoms, and specific examples include a benzyloxycarbonyl group, a phenylethoxycarbonyl group, and 9-fluorenylmethyloxycarbonyl.

  The alkylthio group may be linear, branched or cyclic, and examples thereof include an alkylthio group having 1 to 6 carbon atoms, specifically, a methylthio group, an ethylthio group, an n-propylthio group, a 2-propylthio group, Examples include n-butylthio group, 2-butylthio group, isobutylthio group, tert-butylthio group, pentylthio group, hexylthio group, cyclohexylthio group and the like. As an arylthio group, a C6-C14 arylthio group is mentioned, for example, Specifically, a phenylthio group, a naphthylthio group, etc. are mentioned. Examples of the aralkylthio group include an aralkylthio group having 7 to 12 carbon atoms, and specific examples include a benzylthio group and a 2-phenethylthio group. As the heteroarylthio group, for example, a heteroarylthio group having 2 to 14 carbon atoms containing at least one, preferably 1 to 3 hetero atoms such as nitrogen, oxygen and sulfur atoms as hetero atoms. Specific examples include a 4-pyridylthio group, a 2-benzimidazolylthio group, a 2-benzoxazolylthio group, a 2-benzthiazolylthio group, and the like.

Examples of the sulfinyl group include substituted sulfinyl groups represented by R—SO— (R represents the above alkyl group, aryl group, aralkyl group, etc.). Specific examples of the sulfinyl group include a methanesulfinyl group and a benzenesulfinyl group. Examples of the sulfonyl group include a substituted sulfonyl group represented by R—SO ₂ — (R represents the above alkyl group, aryl group, aralkyl group, etc.). Specific examples of the sulfonyl group include a methanesulfonyl group and a p-toluenesulfonyl group.

  Examples of the silyl group include a tri-substituted silyl group in which three hydrogen atoms on a silicon atom are substituted with a substituent such as the above alkyl group, aryl group, and aralkyl group. Specific examples include a trimethylsilyl group, tert- Examples thereof include a butyldimethylsilyl group, a tert-butyldiphenylsilyl group, and a triphenylsilyl group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Examples of the alkyl group, aryl group and heteroaryl group represented by R ⁹ and R ¹⁰ include the groups described above.

In the general formula (1), R ¹ and R ² , R ² and R ³ , R ³ and R ⁴ , R ⁹ and R ¹⁰ may be bonded to form a ring, and the ring is further bonded A condensed ring may be formed. At least one of R ^{5 to} R ⁸ is substituted with a substituent having the structure of NR ⁹ R ¹⁰ . When R ⁵ is substituted with NR ⁹ R ¹⁰ , R ⁶ and R ⁷ , R ⁷ and R ⁸ may be bonded to form a ring, and the rings are further bonded to form a condensed ring. May be. When R ⁶ is substituted with NR ⁹ R ¹⁰ , R ⁴ and R ⁵ , R ⁷ and R ⁸ may be bonded to form a ring, and the rings are further bonded to form a condensed ring. May be. When R ⁷ is substituted with NR ⁹ R ¹⁰ , R ⁴ and R ⁵ , R ⁵ and R ⁶ may be bonded to form a ring, and the rings are further bonded to form a condensed ring. May be. When R ⁸ is substituted with NR ⁹ R ¹⁰ , R ⁴ and R ⁵ , R ⁵ and R ⁶ , R ⁶ and R ⁷ may be bonded to form a ring, and the ring is further bonded To form a condensed ring. As an example of the case where a ring is formed, an aromatic ring or an aromatic heterocyclic ring which may have a substituent is represented. As an aromatic ring, the aromatic ring which is a C6-C14 monocyclic, polycyclic or condensed ring is mentioned, for example, Specifically, a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring etc. are mentioned. Examples of the substituted aromatic ring include aromatic rings in which at least one hydrogen atom of the aromatic ring is substituted with a substituent. Examples of the substituent include a hydrocarbon group, an aliphatic heterocyclic group, and an aromatic heterocyclic group. Examples of the hydrocarbon group, the aliphatic heterocyclic group and the aromatic heterocyclic group are the same as the substituents described in detail in the description of the general formula (1).

  In the general formula (1), L represents a monovalent anionic ligand. Examples of these anionic ligands include “Photochemistry and Photophysics of Coordination Compounds” Springer-Verlag, H .; Examples include ligands described in Yersin's 1987 issue, “Organometallic Chemistry: Fundamentals and Applications”, Hankabo Publishing Company, Akio Yamamoto, 1982 issue, and the like. As the anionic ligand, a bidentate ligand is preferable, a ligand derived from a diketone compound (for example, acetylacetone, hexafluoroacetylacetone, dibenzoylmethane, etc.), a ligand derived from picolinic acid, tetrapyrazolyl borate, etc. Of these, diketone ligands are more preferred.

  Specific examples of the iridium complex represented by the general formula (1) in the present invention include (1-1) to (1-48) shown below, but the present invention is limited to these. is not.

  Next, the light emitting device of the present invention will be described. The light-emitting element of the present invention is not particularly limited as long as it is an element that uses an iridium complex represented by the general formula (1) (hereinafter sometimes referred to as iridium complex (1)). Those utilizing light emission from the iridium complex, or those utilizing the iridium complex as a charge transport material are preferred. As a typical light emitting element, an organic EL element can be given.

  The light-emitting element of the present invention only needs to contain at least one iridium complex (1). In the light-emitting element in which a light-emitting layer or a plurality of organic compound layers including a light-emitting layer is formed between a pair of electrodes, at least one layer is formed. Contains at least one iridium complex (1). The iridium complex (1) only needs to contain at least one kind, and may be contained in an appropriate combination of two or more kinds. For example, when the iridium complex (1) is used as a doping material for the light emitting layer of an organic EL device, it is possible to obtain a device having excellent color purity and excellent external quantum efficiency and light emission efficiency as compared with a conventionally known device. it can.

  The method for forming the organic layer (organic compound layer) in the light-emitting device of the present invention is not particularly limited, but usually, resistance heating vapor deposition, electron beam, sputtering, molecular lamination method, coating method, ink jet method and the like are used. From the viewpoint of production and production, resistance heating vapor deposition and coating are preferred methods.

  The light-emitting element of the present invention is an element in which a plurality of organic compound thin films including a light-emitting layer or a light-emitting layer are formed between a pair of electrodes of an anode and a cathode. In addition to the light-emitting layer, a hole injection layer, a hole transport layer, An electron injection layer, an electron transport layer, a protective layer, and the like may be provided, and each of these layers may have other functions. In the formation of each of these layers, various conventionally known materials can be used. These layers will be described more specifically.

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

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

  The cathode supplies electrons to the electron injection layer, the electron transport layer, the light emitting layer, etc., and the adhesion, ionization potential, and stability between the negative electrode and the adjacent layer such as the electron injection layer, the electron transport layer, and the light emitting layer. It is selected in consideration of etc. Examples of the cathode material include metals, alloys, metal halides, metal oxides, electrically conductive compounds, and mixtures thereof. Specific examples include alkali metals such as lithium, sodium, and potassium, and fluorides thereof, magnesium. Alkaline earth metals such as calcium and fluorides thereof, gold, silver, lead, aluminum, sodium-potassium alloys or mixed metals thereof, magnesium-silver alloys or mixed metals thereof, rare earth metals such as indium and ytterbium, etc. A material having a work function of 4 eV or less is preferable, and a more preferable material is aluminum, a lithium-aluminum alloy or a mixed metal thereof, a magnesium-silver alloy or a mixed metal thereof.

  The cathode can also have a laminated structure containing the above compound and mixture. The thickness of the cathode can be appropriately selected depending on the material, but is usually preferably in the range of 10 nm to 5 μm, more preferably 50 nm to 1 μm, and further preferably 100 nm to 1 μm. A method such as an electron beam method, a sputtering method, a resistance heating vapor deposition method, or a coating method is used for producing the cathode, and a metal can be vapor-deposited alone or two or more components can be vapor-deposited simultaneously. Furthermore, it is possible to form a pole with an alloy by simultaneously depositing a plurality of metals, or an alloy prepared in advance may be deposited. The sheet resistance of the cathode and the anode is preferably low.

  The material of the light emitting layer is a layer having a function of injecting electrons from an anode or a hole injection layer and a hole transport layer when an electric field is applied, and a function of emitting light by providing a recombination field of holes and electrons. Any material can be used as long as it can be formed. The light emitting layer can be doped with a fluorescent material and a phosphorescent material with high luminous efficiency. For example, benzoxazole derivatives, triphenylamine derivatives, benzimidazole derivatives, benzothiazole derivatives, styrylbenzene derivatives, polyphenyl derivatives, diphenylbutadiene derivatives, tetraphenylbutadiene derivatives, naphthalimide derivatives, coumarin derivatives, perylene derivatives, perinone derivatives, oxadi Metal complexes and rare earth complexes of azole derivatives, aldazine derivatives, pyrazine derivatives, cyclopentadiene derivatives, bisstyrylanthracene derivatives, quinacridone derivatives, pyrrolopyridine derivatives, thiadiazopyridine derivatives, styrylamine derivatives, aromatic dimethylidin compounds, 8-quinolinol derivatives Various metal complexes, polythiophene, polyphenylene, polyphenylene vinylene and other polymer compounds, Silane derivatives, iridium complexes (1) of the present invention, and the like. A single-layer structure composed of one or more of the above materials may be used, or a multi-layer structure composed of a plurality of layers having the same composition or different compositions may be used. Although the film thickness of a light emitting layer is not specifically limited, Usually, the range of 1 nm-5 micrometers is preferable, More preferably, it is 5 nm-1 micrometer, More preferably, it is 10 nm-500 nm. The method for producing the light emitting layer is not particularly limited, but an electron beam method, a sputtering method, a resistance heating vapor deposition method, a molecular lamination method, a coating method (spin coating method, casting method, dip coating method, etc.), an ink jet method. , LB (laser beam) method or the like is used, and resistance heating vapor deposition or coating method is preferable.

  The material of the hole injection layer and the hole transport layer has any one of the function of injecting holes from the anode, the function of transporting holes, and the function of blocking electrons injected from the cathode. It ’s fine. Specific examples include carbazole derivatives, triazole derivatives, oxadiazole derivatives, oxazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, styrylanthracene derivatives, Fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic tertiary amine compounds, styrylamine compounds, aromatic dimethylidin compounds, porphyrin compounds, polysilane compounds, poly (N-vinylcarbazole) derivatives, aniline derivatives Examples thereof include polymers, thiophene oligomers, conductive polymer oligomers such as polythiophene, organosilane derivatives, iridium complexes (1), and the like. The thicknesses of the hole injection layer and the hole transport layer are not particularly limited, but are usually preferably in the range of 1 nm to 5 μm, more preferably 5 nm to 1 μm, and still more preferably 10 nm to 500 nm. The hole injection layer and the hole transport layer may have a single layer structure composed of one or more of the above-described materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions. The hole injection layer and the hole transport layer can be prepared by a vacuum deposition method, an LB method, a method in which the above hole injection / transport agent is dissolved or dispersed in a solvent (a spin coating method, a casting method, a dip coating method). Etc.) and various methods such as an inkjet method are used. In the case of the coating method, the above material can be dissolved or dispersed in a solvent together with the resin component. Examples of the resin component include polyvinyl chloride, polycarbonate, polystyrene, polymethyl methacrylate, polybutyl methacrylate, polyester, polysulfone, polyphenylene oxide, polybutadiene, poly (N-vinylcarbazole), hydrocarbon resin, ketone resin, and phenoxy. Examples thereof include resins, polyamides, ethyl cellulose, vinyl acetate, ABS resins, alkyd resins, epoxy resins, and silicon resins.

  The material of the electron injection layer and the electron transport layer may be any material having any one of the function of injecting electrons from the cathode, the function of transporting electrons, and the function of blocking holes injected from the anode. The ionization potential of the hole blocking layer having a function of blocking holes injected from the anode is selected to be larger than the ionization potential of the light emitting layer.

  Specific examples of materials for the electron injection layer and the electron transport layer include triazole derivatives, oxazole derivatives, polycyclic compounds, heteropolycyclic compounds such as bathocuproine, oxadiazole derivatives, fluorenone derivatives, diphenylquinone derivatives, thiopyrandi. Metal complexes of oxide derivatives, anthraquinone dimethane derivatives, anthrone derivatives, carbodiimide derivatives, fluorenylidenemethane derivatives, distyrylpyrazine derivatives, acid anhydrides such as naphthalenetetracarboxylic acid or perylenetetracarboxylic acid, phthalocyanine derivatives, 8-quinolinol derivatives And various metal complexes represented by metal complexes having metal phthalocyanine, benzoxazole or benzothiazole as a ligand, organosilane derivatives, iridium complex (1) of the present invention, and the like. Although the film thickness of an electron injection layer and an electron carrying layer is not specifically limited, Usually, the range of 1 nm-5 micrometers is preferable, More preferably, it is 5 nm-1 micrometer, More preferably, it is 10 nm-500 nm. The electron injection layer and the electron transport layer may have a single-layer structure made of one or more of the materials described above, or may have a multilayer structure made up of a plurality of layers having the same composition or different compositions. As a method for forming the electron injection layer and the electron transport layer, a vacuum deposition method, an LB method, a method in which the hole injection / transport agent is dissolved or dispersed in a solvent (a spin coating method, a casting method, a dip coating method, etc.) ), An ink jet method or the like is used. In the case of the coating method, the material is dissolved or dispersed together with the resin component. At this time, what was illustrated in the case of a positive hole injection layer and a positive hole transport layer can be used as a resin component.

  As the material for the protective layer, any material can be used as long as it has a function of preventing substances that promote element deterioration such as moisture and oxygen from entering the element. Specific examples of the protective layer material include metals such as indium, tin, lead, gold, silver, copper, aluminum, titanium, nickel, magnesium oxide, silicon dioxide, dialuminum trioxide, germanium oxide, nickel oxide, calcium oxide, Metal oxides such as barium oxide, ferric trioxide, ytterbium trioxide, titanium oxide, magnesium fluoride, lithium fluoride, aluminum fluoride, calcium fluoride metal fluoride, polyethylene, polypropylene, polymethyl methacrylate, polyimide , Polyurea, polytetrafluoroethylene, polychlorotrifluoroethylene, polydichlorodifluoroethylene, a copolymer of chlorotrifluoroethylene and dichlorodifluoroethylene, and a monomer mixture containing tetrafluoroethylene and at least one comonomer A copolymer obtained by copolymerizing the above, a fluorine-containing copolymer having a cyclic structure in the copolymer main chain, a water-absorbing substance having a water absorption of 1% or more, a moisture-proof substance having a water absorption of 0.1% or less, and the like. It is done. There is no particular limitation on the method for forming the protective layer. For example, vacuum deposition, sputtering, reactive sputtering, MBE (molecular beam epitaxy), cluster ion beam, ion plating, plasma polymerization (high frequency excitation ions) Plating method), plasma CVD method, laser CVD method, thermal CVD method, gas source CVD method, coating method and the like can be applied.

  Next, the iridium complex represented by the general formula (1) used in the light-emitting device of the present invention can be synthesized using known means. For example, a method in which a solvent amount of a ligand and iridium (III) chloride hydrate are reacted at a high temperature in the presence of a silver salt and water (for example, see WO 02/02714) is known. The yield of the target product in this method is reported to be 10% to 82%. Also known is a method in which a theoretical amount of a ligand and iridium (III) acetylacetonate are reacted in glycerol at a high temperature (for example, see WO 02/15645). The yield of the target product is 75%. It has been reported. Although the yield is moderate, these methods have severe reaction conditions, and in this method, only three of the same iridium ligands can be synthesized. As an improved method, a theoretical amount of a ligand and iridium (III) chloride hydrate are used as raw materials, and the Nonoyama method (M. Nonoyama et al., “Bulten of the Chemical Society of Japan ( Bull. Chem. Soc. Jpn.), 47, 3, 1974, pp. 767-768) was used to synthesize a trivalent hexacoordinate orthometalated iridium binuclear complex. , Then reacting with acetylacetone in the presence of a base to give an acetylacetonate complex, which is reacted with a theoretical amount of ligand in glycerol at high temperature to synthesize a trivalent hexacoordinate orthometalated iridium complex Methods have been reported (S. Lamansky et al., “Journal of the American Chemical Society (J. Am. C. hem. Soc.), 123, 2001, pages 4304-4312; S. Lamansky et al., “Inorganic. Chem.”, 40, 2001, pages 1704-1711. Page; see JP-A No. 2002-105055). In this method, the yield of the first stage is reported to be 75% or more, the yield of the second stage is 75 to 90%, and the yield of the third stage is 85%. According to this method, the same complex can be made separately from a complex having two different ligands using a common raw material.

  Particularly preferable examples of the iridium complex (1) synthesized by the above method include the following complexes.

  Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited thereto.

Example 1 Synthesis of Exemplary Compound (1-1)

アルゴン雰囲気下の反応容器に三塩化イリジウム（ＩＩＩ）水和物（１５０ｍｇ、０．４８ｍｍｏｌ）、２−（３−（Ｎ，Ｎ’−ジフェニルアミノ）フェニル）ピリジン（３８３ｍｇ、１．２ｍｍｏｌ）、２−エトキシエタノール（４．５ｍｌ）と脱イオン水（１．５ｍｌ）の混合溶媒を入れ、１２０℃で２４時間攪拌した。反応終了後、室温まで冷やし、エタノールとヘキサンを加えて結晶を析出させた。その結晶をろ過することで赤色固体のビス（２−（５−（Ｎ，Ｎ’−ジフェニルアミノ）フェニル）ピリジナト−Ｎ，Ｃ^２’）イリジウム（ＩＩＩ）クロライド ダイマー（Ａ）（３８５ｍｇ）が収率９２％で得られた。

In a reaction vessel under an argon atmosphere, iridium (III) trichloride hydrate (150 mg, 0.48 mmol), 2- (3- (N, N′-diphenylamino) phenyl) pyridine (383 mg, 1.2 mmol), 2 -A mixed solvent of ethoxyethanol (4.5 ml) and deionized water (1.5 ml) was added and stirred at 120 ° C for 24 hours. After completion of the reaction, the mixture was cooled to room temperature, and ethanol and hexane were added to precipitate crystals. The crystals were filtered to obtain red solid bis (2- (5- (N, N′-diphenylamino) phenyl) pyridinato-N, C ^{2 ′} ) iridium (III) chloride dimer (A) (385 mg). The rate was 92%.

Subsequently, the bis (2- (5- (N, N′-diphenylamino) phenyl) pyridinato-N, C ^{2 ′} ) iridium (III) chloride dimer (A) obtained above was placed in a reaction vessel under an argon atmosphere. (300 mg, 0.17 mmol), acetylacetone (52 mg, 0.52 mmol), sodium carbonate (127 mg, 1.2 mmol) and 2-ethoxyethanol (9 ml) were added and stirred at 120 ° C. for 12 hours. After completion of the reaction, the solvent was distilled off under reduced pressure, and dichloromethane and water were added to the residue and extracted three times. The organic layer was dried over sodium sulfate, the solvent was distilled off, and the residue was purified by column chromatography (alumina; chloroform) to obtain red solid bis (2- (5- (N, N′-diphenylamino) phenyl) pyridinato-N, C ^{2 ′} ) iridium (III) acetylacetonate (Exemplary Compound (1-1)) (232 mg) was obtained in a yield of 72%.
¹ H NMR (200 MHz, CD ₂ Cl ₂ ): δ 8.24 (brd, J = 5.8 Hz, 2H), 7.39 (brt, J = 8.2 Hz, 2H), 7.30 (d, J = 8.8 Hz, 2H), 7.13 (brt, J = 7.6 Hz, 9H), 6.93 (brt, J = 8.2 Hz, 12H), 6.79 (brt, J = 6.8 Hz, 3H), 6.49 (dd, J = 2.2, 8.6 Hz, 2H), 5.77 (d, J = 2.2 Hz, 2H), 5.23 (s, 1H), 1.81 ( s, 6H)

Example 2 Synthesis of Exemplary Compound (1-2)

アルゴン雰囲気下の反応容器に三塩化イリジウム（ＩＩＩ）水和物（１１５ｍｇ、０．３６ｍｍｏｌ）、２−（４−（Ｎ，Ｎ’−ジフェニルアミノ）フェニル）ピリジン（２９４ｍｇ、０．９１ｍｍｏｌ）、２−エトキシエタノール（３ｍｌ）と脱イオン水 （１ｍｌ）の混合溶媒を入れ、実施例１と同様に反応、後処理を行うことによって黄色固体のビス（２−（４−（Ｎ，Ｎ’−ジフェニルアミノ）フェニル）ピリジナト−Ｎ，Ｃ^２’）イリジウム（ＩＩＩ）クロライド ダイマー（Ｂ）（２３８ｍｇ）が収率７５％で得られた。

In a reaction vessel under an argon atmosphere, iridium trichloride (III) hydrate (115 mg, 0.36 mmol), 2- (4- (N, N′-diphenylamino) phenyl) pyridine (294 mg, 0.91 mmol), 2 -A mixed solvent of ethoxyethanol (3 ml) and deionized water (1 ml) was added and reacted and worked up in the same manner as in Example 1 to give bis (2- (4- (N, N'-diphenyl) as a yellow solid. Amino) phenyl) pyridinato-N, C ^{2 ′} ) iridium (III) chloride dimer (B) (238 mg) was obtained in a yield of 75%.

Subsequently, bis (2- (4- (N, N′-diphenylamino) phenyl) pyridinato-N, C ^{2 ′} ) iridium (III) chloride dimer (B) (300 mg, 0.17 mmol) was placed in a reaction vessel under an argon atmosphere. ), Acetylacetone (52 mg, 0.52 mmol), sodium carbonate (127 mg, 1.2 mmol) and 2-ethoxyethanol (9 ml) were added, and a yellow solid bis ( 2- (4- (N, N′-diphenylamino) phenyl) pyridinato-N, C ^{2 ′} ) iridium (III) acetylacetonate (1-2) (150 mg) was obtained in a yield of 47%.
¹ H NMR (200 MHz, CD ₂ Cl ₂ ): δ 8.53 (brd, J = 5.4 Hz, 2H), 7.64 (brd, J = 3.8 Hz, 4H), 7.37 (d, J = 2.2 Hz, 2H), 7.21-7.00 (m, 18H), 6.89 (brt, J = 7.6 Hz, 4H), 6.56 (dd, J = 2.4, 8.). 0 Hz, 2H), 6.18 (brd, J = 8.2 Hz, 2H), 5.25 (s, 1H), 1.84 (s, 6H)

Example 3 Synthesis of Exemplary Compound (1-3)

アルゴン雰囲気下の反応容器に三塩化イリジウム（ＩＩＩ）水和物（２００ｍｇ、０．６４ｍｍｏｌ）、１−（３−（Ｎ，Ｎ’−ジフェニルアミノ）フェニル）イソキノリン（７０６ｍｇ、１．９ｍｍｏｌ）、２−エトキシエタノール（６ｍｌ）と脱イオン水（２ｍｌ）の混合溶媒を入れ、合成例１と同様に反応、後処理を行うことによって赤紫色固体のビス（１−（５−（Ｎ，Ｎ’−ジフェニルアミノ）フェニル）イソキノリノ−Ｎ，Ｃ^２’）イリジウム（ＩＩＩ）クロライド ダイマー（Ｃ）（４４３ｍｇ）が収率７２％で得られた。

In a reaction vessel under an argon atmosphere, iridium trichloride (III) hydrate (200 mg, 0.64 mmol), 1- (3- (N, N′-diphenylamino) phenyl) isoquinoline (706 mg, 1.9 mmol), 2 -A mixed solvent of ethoxyethanol (6 ml) and deionized water (2 ml) was added, and reaction and post-treatment were carried out in the same manner as in Synthesis Example 1 to obtain red purple solid bis (1- (5- (N, N'- Diphenylamino) phenyl) isoquinolino-N, C ^{2 ′} ) iridium (III) chloride dimer (C) (443 mg) was obtained in a yield of 72%.

Subsequently, bis (1- (5- (N, N′-diphenylamino) phenyl) isoquinolino-N, C ^{2 ′} ) iridium (III) chloride dimer (C) (300 mg, 0.15 mmol) was placed in a reaction vessel under an argon atmosphere. ), Acetylacetone (46 mg, 0.46 mmol), sodium carbonate (114 mg, 1.1 mmol) and 2-ethoxyethanol (9 ml) were added, followed by reaction and post-treatment in the same manner as in Example 1 to obtain a red-purple solid bis. (1- (5- (N, N′-diphenylamino) phenyl) isoquinolino-N, C ^{2 ′} ) iridium (III) acetylacetonate (1-3) (174 mg) was obtained in a yield of 55%.
¹ H NMR (200 MHz, CD ₂ Cl ₂ ): δ 8.50 (brd, J = 9.0 Hz, 2H), 8.45 (d, J = 6.4 Hz, 2H), 7.94 (d, J = 2.0 Hz, 2H), 7.85 (brd, J = 8.6 Hz, 2H), 7.61 (brt, J = 7.2 Hz, 2H), 7.45 (brt, J = 6.6 Hz, 4H), 7.19 (brt, J = 7.0 Hz, 8H), 7.07 (brd, J = 7.4 Hz, 8H), 6.91 (brt, J = 7.0 Hz, 4H), 6. 55 (dd, J = 2.2, 8.0 Hz, 2H), 6.27 (d, J = 8.0 Hz, 2H), 5.25 (s, 1H), 1.81 (s, 6H)

Example 4
On a glass substrate (g), an anode (f), a hole transport layer (e), a light emitting layer (d) composed of a host material and a dope material, a hole blocking layer (c), an electron transport layer (b) and a cathode By forming (a) in order from the glass substrate (g) side, an organic EL device having the layer configuration shown in FIG. 1 was produced. In this organic EL element, a lead wire is connected to the anode (f) and the cathode (a), respectively, so that a voltage can be applied between the anode (f) and the cathode (a). Specific materials and manufacturing methods of each layer will be briefly described below.
The anode (f) is made of an ITO film and is attached to the glass substrate (g). The hole transport layer (e) was formed with a thickness of 40 nm on the anode (f) by vacuum deposition using a compound (α-NPD) represented by the following formula.

一方、ホスト材料とドープしたリン光発光材料を含む発光層（ｄ）は、下記式で示される化合物（ＣＢＰ）と合成例１で製造した下記式で示される化合物（１−１）の両者を用い、同時に真空蒸着（ドープ６重量％）を行い、正孔輸送層（ｅ）上に３５ｎｍの厚さとして形成した。

On the other hand, the light-emitting layer (d) containing the host material and the doped phosphorescent light-emitting material comprises both the compound (CBP) represented by the following formula and the compound (1-1) represented by the following formula produced in Synthesis Example 1. At the same time, vacuum deposition (6% by weight of dope) was performed to form a thickness of 35 nm on the hole transport layer (e).

さらに、正孔ブロッキング層（ｃ）は、下記式で示される化合物（ＢＣＰ）を用い、真空蒸着法にて発光層（ｄ）上に１０ｎｍの厚さで形成した。

Furthermore, the hole blocking layer (c) was formed with a thickness of 10 nm on the light emitting layer (d) by a vacuum deposition method using a compound (BCP) represented by the following formula.

電子輸送層（ｂ）は下記式で示される化合物（Ａｌｑ₃）を用い、真空蒸着法にて正孔ブロッキング層（ｃ）上に３５ｎｍの厚さで形成した。

The electron transport layer (b) was formed with a thickness of 35 nm on the hole blocking layer (c) by a vacuum vapor deposition method using a compound (Alq ₃ ) represented by the following formula.

陰極（ａ）は、電子輸送層（ｂ）側から順に、ＬｉＦを０．５ｎｍの厚さで真空蒸着した後、Ａｌをさらに１００ｎｍの厚さで真空蒸着した積層体により構成した。
得られた有機ＥＬ素子の陽極（ＩＴＯ）（ｆ）側にプラス、陰極（ａ）側にマイナスの電圧を印加したところ、低い電圧から安定な発光が確認された。素子の外部量子効率は、輝度１００ｃｄ／ｍ^２において７．６％と高効率であった。さらに、発光層（ｄ）に用いた化合物（１−１）に起因する橙色発光が得られた。

（実施例５）
実施例４と同様の素子構造を有し、発光層（ｄ）に含まれるドーパントとして実施例２で得られたイリジウム錯体（１−２）を用いる以外は実施例４と同様に素子を作製した。
得られた有機ＥＬ素子の陽極（ＩＴＯ）（ｆ）側にプラス、陰極（ａ）側にマイナスの電圧を印加したところ、低い電圧から安定な発光が確認された。素子の外部量子効率は、輝度１００ｃｄ／ｍ^２において１１．８％と極めて高効率であった。さらに、発光層（ｄ）に用いた化合物（１−２）に起因する黄緑色発光が得られた。
実施例４及び実施例５で作成した素子特性について以下の表に示す。

The cathode (a) was composed of a laminate in which LiF was vacuum-deposited in a thickness of 0.5 nm and Al was further vacuum-deposited in a thickness of 100 nm in this order from the electron transport layer (b) side.
When a positive voltage was applied to the anode (ITO) (f) side of the obtained organic EL element and a negative voltage was applied to the cathode (a) side, stable light emission was confirmed from a low voltage. The external quantum efficiency of the device was as high as 7.6% at a luminance of 100 cd / m ² . Furthermore, orange light emission resulting from the compound (1-1) used for the light emitting layer (d) was obtained.

(Example 5)
A device was produced in the same manner as in Example 4 except that the iridium complex (1-2) obtained in Example 2 was used as the dopant contained in the light emitting layer (d), which had the same device structure as in Example 4. .
When a positive voltage was applied to the anode (ITO) (f) side of the obtained organic EL element and a negative voltage was applied to the cathode (a) side, stable light emission was confirmed from a low voltage. The external quantum efficiency of the device was extremely high at 11.8% at a luminance of 100 cd / m ² . Furthermore, yellowish green light emission resulting from the compound (1-2) used for the light emitting layer (d) was obtained.
The device characteristics prepared in Example 4 and Example 5 are shown in the following table.

It is a schematic cross section which shows the layer structure of the organic EL element of this invention.

Explanation of symbols

(A) cathode (b) electron transport layer (c) hole blocking layer (d) light emitting layer (e) hole transport layer (f) anode (g) glass substrate

Claims (6)

In a light emitting element in which a light emitting layer or a plurality of organic compound thin layers including a light emitting layer is formed between a pair of electrodes, at least one layer is a layer containing at least one iridium complex represented by the following general formula (1). A light emitting device characterized by the above.

(In the formula, R ^{1 to} R ⁸ each independently represents a hydrogen atom or a substituent. However, R ¹ and R ² , R ² and R ³ , R ³ and R ⁴ are bonded to form a ring. The ring may be further bonded to form a condensed ring, and at least one of R ^{5 to} R ⁸ is substituted with a substituent having the structure of NR ⁹ R ¹⁰ , ^{When 5} is substituted with NR ⁹ R ¹⁰ , R ⁶ and R ⁷ , R ⁷ and R ⁸ may be bonded to form a ring, and the ring is further bonded to form a condensed ring. When R ⁶ is substituted with NR ⁹ R ¹⁰ , R ⁴ and R ⁵ , R ⁷ and R ⁸ may be bonded to form a ring, and the ring is further bonded to form a condensed ring. good .R ⁷ be formed is if it is substituted with ^NR 9 ^{R 10} forms a ring each ^{R 4} and ^R 5, ^{R 5} and ^{R 6} Well, the ring further when bound to good .R ⁸ also form a condensed ring is substituted with ^NR 9 ^{R 10} is ^{R 4} and ^R 5, ^{R 5} and ^R 6, ^{R 6} and ^{R 7} R ⁹ and R ¹⁰ each independently represents an alkyl group, an aryl group, or a heteroaryl group, which may be bonded to each other to form a ring, which may be further bonded to form a condensed ring. N ¹ represents an integer of 1 or 2, n ² is ² when n ¹ is 1, and 1 when n ¹ is 2. L represents a monovalent anionic ligand.) The light emitting device according to claim 1, wherein the iridium complex is a complex represented by the following general formula (2) or (3).

(In formulas (2) and (3), R ¹¹ and R ¹² each independently represent a phenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, or carbazolyl with NR ¹¹ R ¹² . R ¹³ represents a phenyl group or a trifluoromethyl group, n ³ represents an integer of 0, 1 or 2. Q represents acetylacetonate or picolinate.   3. The light emitting device according to claim 1, wherein the iridium complex contained in at least one layer can act as a doping material in the light emitting layer of the organic electroluminescence device.   The light-emitting element according to claim 1, wherein the layer containing the light-emitting material is formed by a coating process. An iridium complex represented by the following general formula (1).

(In the formula, R ^{1 to} R ⁸ each independently represents a hydrogen atom or a substituent. However, R ¹ and R ² , R ² and R ³ , R ³ and R ⁴ are bonded to form a ring. The ring may be further bonded to form a condensed ring, and at least one of R ^{5 to} R ⁸ is substituted with a substituent having the structure of NR ⁹ R ¹⁰ , ^{When 5} is substituted with NR ⁹ R ¹⁰ , R ⁶ and R ⁷ , R ⁷ and R ⁸ may be bonded to form a ring, and the ring is further bonded to form a condensed ring. When R ⁶ is substituted with NR ⁹ R ¹⁰ , R ⁴ and R ⁵ , R ⁷ and R ⁸ may be bonded to form a ring, and the ring is further bonded to form a condensed ring. good .R ⁷ be formed is if it is substituted with ^NR 9 ^{R 10} forms a ring each ^{R 4} and ^R 5, ^{R 5} and ^{R 6} Well, the ring further when bound to good .R ⁸ also form a condensed ring is substituted with ^NR 9 ^{R 10} is ^{R 4} and ^R 5, ^{R 5} and ^R 6, ^{R 6} and ^{R 7} R ⁹ and R ¹⁰ each independently represents an alkyl group, an aryl group, or a heteroaryl group, which may be bonded to each other to form a ring, which may be further bonded to form a condensed ring. N ¹ represents an integer of 1 or 2, n ² is ² when n ¹ is 1, and 1 when n ¹ is 2. L represents a monovalent anionic ligand.) The iridium complex represented by the following general formula (2) or general formula (3).

(In formulas (2) and (3), R ¹¹ and R ¹² each independently represent a phenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, or carbazolyl with NR ¹¹ R ¹² . R ¹³ represents a phenyl group or a trifluoromethyl group, n ³ represents an integer of 0, 1 or 2. Q represents acetylacetonate or picolinate.

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