JP2007176917A - Organometallic complex, light-emitting element using it, light-emitting device and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organometallic complex that can increase recombination efficiency of electrons and holes. <P>SOLUTION: The organometallic complex containing a structure represented by general formula (1): wherein, R<SP>1</SP>and R<SP>2</SP>indicate each independently any one group selected from among a halogen group, a -CF<SB>3</SB>group, a cyano group and an alkoxycarbonyl group; R<SP>3</SP>and R<SP>4</SP>indicate each independently either a hydrogen atom or an alkyl group of 1 to 4 carbon atoms; and M indicates an element that belongs to either the group 9 or the group 10 of the periodic table. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a substance that can emit light by current excitation, and particularly relates to an organometallic complex that emits light by current excitation. In addition, the present invention relates to a light-emitting element and a light-emitting device using the substance.

  A light-emitting element having a layer containing a light-emitting substance between a pair of electrodes is used as a pixel, a light source, or the like, and is provided in a light-emitting device such as a display device or a lighting device. When a current is passed between the pair of electrodes in the light-emitting element, fluorescence or phosphorescence is emitted from the excited light-emitting substance.

  Comparing fluorescence and phosphorescence, in the case of current excitation, theoretically, the internal quantum efficiency of phosphorescence is about three times the internal quantum efficiency of fluorescence. For this reason, it is considered that the use of a light-emitting substance that emits phosphorescence rather than fluorescence increases the light emission efficiency, and so far, substances that emit phosphorescence have been developed.

  For example, Non-Patent Document 1 describes a metal complex having iridium as a central metal. According to Non-Patent Document 1, this metal complex can be used as a material for a light emitting device.

  By the way, in the case of a light-emitting element that emits light by current excitation, it is not necessary that current only flows, and it is necessary to recombine electrons and holes well. By increasing the recombination efficiency between electrons and holes, the excitation energy is efficiently generated, and as a result, the light emission efficiency is improved.

  Up to now, it has been widely known and developed that the emission efficiency can be increased by using a substance having a high internal quantum efficiency as described above. However, a substance that can improve the recombination efficiency is still under development. did not exist.

“New Iridium Complexes as Highly Efficient Orange-Red Emitters in Organic Light-Emitting Diodes”, Jun-Pay Duan et al. , Advanced Materials 2003 15 No. 3, February 5,224-228

  An object of the present invention is to provide an organometallic complex that can increase the recombination efficiency of electrons and holes. Another object of the present invention is to provide an organometallic complex that can emit phosphorescence. Another object of the present invention is to provide a light-emitting element with high light emission efficiency.

  One aspect of the present invention is an organometallic complex including a structure represented by the general formula (1).

In the general formula (1), R ¹ and R ² each represent an electron-withdrawing substituent. R ³ and R ⁴ each represent either hydrogen or an alkyl group having 1 to 4 carbon atoms. M represents a Group 9 element or a Group 10 element. Here, the electron-withdrawing substituent is preferably any group selected from a halogen group, a —CF ₃ group, a cyano group, and an alkoxycarbonyl group. In order to improve the chemical stability, it is particularly preferable to use a fluoro group among the halogen groups. In addition, the alkyl group having 1 to 4 carbon atoms is preferably any group selected from a methyl group, an ethyl group, an isopropyl group, and a sec-butyl group. Further, iridium is particularly preferable among Group 9 elements, and platinum is particularly preferable among Group 10 elements.

  One aspect of the present invention is an organometallic complex represented by the general formula (2).

In the general formula (2), R ⁵ and R ⁶ each represent an electron-withdrawing substituent. R ⁷ and R ⁸ each represent either hydrogen or an alkyl group having 1 to 4 carbon atoms. M represents a Group 9 element or a Group 10 element. n is n = 2 when M is a Group 9 element, and n = 1 when M is a Group 10 element. L is a monoanionic ligand having a beta diketone structure, a monoanionic bidentate chelate ligand having a carboxyl group, or a monoanionic bidentate chelate ligand having a phenolic hydroxyl group Represents one of the following. Here, the electron-withdrawing substituent is preferably any group selected from a halogen group, a —CF ₃ group, a cyano group, and an alkoxycarbonyl group. In order to improve the chemical stability, it is particularly preferable to use a fluoro group among the halogen groups. In addition, the alkyl group having 1 to 4 carbon atoms is preferably any group selected from a methyl group, an ethyl group, an isopropyl group, and a sec-butyl group. Further, iridium is particularly preferable among Group 9 elements, and platinum is particularly preferable among Group 10 elements.

  One aspect of the present invention is an organometallic complex including a structure represented by the general formula (3).

In the general formula (3), R ⁹ and R ¹⁰ each represent an electron-withdrawing substituent. R ¹¹ and R ¹² each represent hydrogen or an alkyl group having 1 to 4 carbon atoms. Here, the electron-withdrawing substituent is preferably any group selected from a halogen group, a —CF ₃ group, a cyano group, and an alkoxycarbonyl group. In order to improve the chemical stability, it is particularly preferable to use a fluoro group among the halogen groups. In addition, the alkyl group having 1 to 4 carbon atoms is preferably any group selected from a methyl group, an ethyl group, an isopropyl group, and a sec-butyl group.

  One aspect of the present invention is an organometallic complex including a structure represented by the general formula (4).

In the general formula (4), R ¹³ and R ¹⁴ each represent an electron-withdrawing substituent. R ¹⁵ and R ¹⁶ each represent either hydrogen or an alkyl group having 1 to 4 carbon atoms. L is a monoanionic ligand having a beta diketone structure, a monoanionic bidentate chelate ligand having a carboxyl group, or a monoanionic bidentate chelate ligand having a phenolic hydroxyl group Represents one of the following. Here, the electron-withdrawing substituent is preferably any group selected from a halogen group, a —CF ₃ group, a cyano group, and an alkoxycarbonyl group. In addition, the alkyl group having 1 to 4 carbon atoms is preferably any group selected from a methyl group, an ethyl group, an isopropyl group, and a sec-butyl group.

  One aspect of the present invention is an organometallic complex including a structure represented by the general formula (5).

In the general formula (5), R ¹⁷ and R ¹⁸ each represents an electron-withdrawing substituent. R ¹⁹ represents either hydrogen or an alkyl group having 1 to 4 carbon atoms. Here, the electron-withdrawing substituent is preferably any group selected from a halogen group, a —CF ₃ group, a cyano group, and an alkoxycarbonyl group. In order to improve the chemical stability, it is particularly preferable to use a fluoro group among the halogen groups. In addition, the alkyl group having 1 to 4 carbon atoms is preferably any group selected from a methyl group, an ethyl group, an isopropyl group, and a sec-butyl group.

  One aspect of the present invention is an organometallic complex including a structure represented by the general formula (6).

In the general formula (6), R ²⁰ and R ²¹ each represent an electron-withdrawing substituent. R ²² represents either hydrogen or an alkyl group having 1 to 4 carbon atoms. L is a monoanionic ligand having a beta diketone structure, a monoanionic bidentate chelate ligand having a carboxyl group, or a monoanionic bidentate chelate ligand having a phenolic hydroxyl group Represents one of the following. Here, the electron-withdrawing substituent is preferably any group selected from a halogen group, a —CF ₃ group, a cyano group, and an alkoxycarbonyl group. In order to improve the chemical stability, it is particularly preferable to use a fluoro group among the halogen groups. In addition, the alkyl group having 1 to 4 carbon atoms is preferably any group selected from a methyl group, an ethyl group, an isopropyl group, and a sec-butyl group.

  In the organometallic complexes represented by the general formulas (2), (4), and (6), L is specifically a ligand represented by the following structural formulas (1) to (7). It is preferably any ligand selected from the inside. All of the ligands represented by the structural formulas (1) to (7) are monoanionic ligands.

  One aspect of the present invention is an organometallic complex including a structure represented by the general formula (7).

In the general formula (7), R ^{23 to} R ²⁶ each represents an electron-withdrawing substituent. R ²⁷ and R ²⁸ each represent either hydrogen or an alkyl group having 1 to 4 carbon atoms. M represents a Group 9 element or a Group 10 element. Here, the electron-withdrawing substituent is preferably any group selected from a halogen group, a —CF ₃ group, a cyano group, and an alkoxycarbonyl group. In order to improve the chemical stability, it is particularly preferable to use a fluoro group among the halogen groups. Further, iridium is particularly preferable among Group 9 elements, and platinum is particularly preferable among Group 10 elements.

  One aspect of the present invention is an organometallic complex represented by General Formula (8).

In General formula (8), R < ²⁹ > -R < ³² > represents an electron withdrawing substituent, respectively. R ³³ and R ³⁴ each represent either hydrogen or an alkyl group having 1 to 4 carbon atoms. M represents a Group 9 element or a Group 10 element. n is n = 2 when M is a Group 9 element, and n = 1 when M is a Group 10 element. L is a monoanionic ligand having a beta diketone structure, a monoanionic bidentate chelate ligand having a carboxyl group, or a monoanionic bidentate chelate ligand having a phenolic hydroxyl group Represents one of the following. Here, the electron-withdrawing substituent is preferably any group selected from a halogen group, a —CF ₃ group, a cyano group, and an alkoxycarbonyl group. In order to improve the chemical stability, it is particularly preferable to use a fluoro group among the halogen groups. Further, iridium is particularly preferable among Group 9 elements, and platinum is particularly preferable among Group 10 elements.

  One aspect of the present invention is an organometallic complex including a structure represented by the general formula (9).

In the general formula (9), R ^{35 to} R ³⁸ each represents an electron-withdrawing substituent. R ³⁹ and R ⁴⁰ each represent either hydrogen or an alkyl group having 1 to 4 carbon atoms. Here, the electron-withdrawing substituent is preferably any group selected from a halogen group, a —CF ₃ group, a cyano group, and an alkoxycarbonyl group. In order to improve the chemical stability, it is particularly preferable to use a fluoro group among the halogen groups.

  One aspect of the present invention is an organometallic complex including a structure represented by the general formula (10).

In the general formula (10), R ^{41 to} R ⁴⁴ each represents an electron-withdrawing substituent. R ⁴⁵ and R ⁴⁶ each represent either hydrogen or an alkyl group having 1 to 4 carbon atoms. L is a monoanionic ligand having a beta diketone structure, a monoanionic bidentate chelate ligand having a carboxyl group, or a monoanionic bidentate chelate ligand having a phenolic hydroxyl group Represents one of the following. Here, the electron-withdrawing substituent is preferably any group selected from a halogen group, a —CF ₃ group, a cyano group, and an alkoxycarbonyl group. In order to improve the chemical stability, it is particularly preferable to use a fluoro group among the halogen groups.

  One aspect of the present invention is an organometallic complex including a structure represented by the general formula (11).

In the general formula (11), R ^{47 to} R ⁵⁰ each represent an electron-withdrawing substituent. R ⁵¹ represents either hydrogen or an alkyl group having 1 to 4 carbon atoms. Here, the electron-withdrawing substituent is preferably any group selected from a halogen group, a —CF ₃ group, a cyano group, and an alkoxycarbonyl group. In order to improve the chemical stability, it is particularly preferable to use a fluoro group among the halogen groups. In addition, the alkyl group having 1 to 4 carbon atoms is preferably any group selected from a methyl group, an ethyl group, an isopropyl group, and a sec-butyl group.

  One aspect of the present invention is an organometallic complex including a structure represented by the general formula (12).

In the general formula (12), R ^{52 to} R ⁵⁵ each represents an electron-withdrawing substituent. R ⁵⁶ represents either hydrogen or an alkyl group having 1 to 4 carbon atoms. L is a monoanionic ligand having a beta diketone structure, a monoanionic bidentate chelate ligand having a carboxyl group, or a monoanionic bidentate chelate ligand having a phenolic hydroxyl group Represents one of the following. Here, the electron-withdrawing substituent is preferably any group selected from a halogen group, a —CF ₃ group, a cyano group, and an alkoxycarbonyl group. In order to improve the chemical stability, it is particularly preferable to use a fluoro group among the halogen groups. In addition, the alkyl group having 1 to 4 carbon atoms is preferably any group selected from a methyl group, an ethyl group, an isopropyl group, and a sec-butyl group.

  In the organometallic complex represented by the general formulas (8), (10), and (12), L is any selected from the ligands represented by the following structural formulas (1) to (7). Such a ligand is preferable. All of the ligands represented by the structural formulas (1) to (7) are monoanionic ligands.

  One aspect of the present invention is an organometallic complex including a structure represented by the general formula (13).

In the general formula (13), R ^{57 to} R ⁶² each represent an electron-withdrawing substituent. R ⁶³ and R ⁶⁴ each represent hydrogen or an alkyl group having 1 to 4 carbon atoms. M represents a Group 9 element or a Group 10 element. Here, the electron-withdrawing substituent is preferably a halogen group or a —CF ₃ group. In order to improve the chemical stability, it is particularly preferable to use a fluoro group among the halogen groups. Further, iridium is particularly preferable among Group 9 elements, and platinum is particularly preferable among Group 10 elements. In addition, the alkyl group having 1 to 4 carbon atoms is preferably any group selected from a methyl group, an ethyl group, an isopropyl group, and a sec-butyl group.

  One aspect of the present invention is an organometallic complex represented by General Formula (14).

In the general formula (14), R ^{65 to} R ⁷⁰ each represent an electron-withdrawing substituent. R ⁷¹ and R ⁷² each represent either hydrogen or an alkyl group having 1 to 4 carbon atoms. M represents a Group 9 element or a Group 10 element. n is n = 2 when M is a Group 9 element, and n = 1 when M is a Group 10 element. L is a monoanionic ligand having a beta diketone structure, a monoanionic bidentate chelate ligand having a carboxyl group, or a monoanionic bidentate chelate ligand having a phenolic hydroxyl group Represents one of the following. Here, the electron-withdrawing substituent is preferably a halogen group or a —CF ₃ group. In order to improve the chemical stability, it is particularly preferable to use a fluoro group among the halogen groups. Further, iridium is particularly preferable among Group 9 elements, and platinum is particularly preferable among Group 10 elements. In addition, the alkyl group having 1 to 4 carbon atoms is preferably any group selected from a methyl group, an ethyl group, an isopropyl group, and a sec-butyl group.

  One aspect of the present invention is an organometallic complex including a structure represented by the general formula (15).

In the general formula (15), R ^{73 to} R ⁷⁸ each represents an electron-withdrawing substituent. R ⁷⁹ and R ⁸⁰ each represent hydrogen or an alkyl group having 1 to 4 carbon atoms. Here, the electron-withdrawing substituent is preferably a halogen group or a —CF ₃ group. In order to improve the chemical stability, it is particularly preferable to use a fluoro group among the halogen groups. In addition, the alkyl group having 1 to 4 carbon atoms is preferably any group selected from a methyl group, an ethyl group, an isopropyl group, and a sec-butyl group.

  One aspect of the present invention is an organometallic complex including a structure represented by the general formula (16).

In the general formula (16), R ^{81 to} R ⁸⁶ each represents an electron-withdrawing substituent. R ⁸⁷ and R ⁸⁸ each represent either hydrogen or an alkyl group having 1 to 4 carbon atoms. L is a monoanionic ligand having a beta diketone structure, a monoanionic bidentate chelate ligand having a carboxyl group, or a monoanionic bidentate chelate ligand having a phenolic hydroxyl group Represents one of the following. Here, the electron-withdrawing substituent is preferably a halogen group or a —CF ₃ group. In order to improve the chemical stability, it is particularly preferable to use a fluoro group among the halogen groups. In addition, the alkyl group having 1 to 4 carbon atoms is preferably any group selected from a methyl group, an ethyl group, an isopropyl group, and a sec-butyl group.

  One aspect of the present invention is an organometallic complex including a structure represented by General Formula (17).

In the general formula (17), R ^{89 to} R ⁹⁴ each represent an electron-withdrawing substituent. ^{Also, R 95} represents hydrogen or an alkyl group having 1 to 4 carbon atoms. Here, the electron-withdrawing substituent is preferably a halogen group or a —CF ₃ group. In order to improve the chemical stability, it is particularly preferable to use a fluoro group among the halogen groups. In addition, the alkyl group having 1 to 4 carbon atoms is preferably any group selected from a methyl group, an ethyl group, an isopropyl group, and a sec-butyl group.

  One aspect of the present invention is an organometallic complex including a structure represented by the general formula (18).

In the general formula (18), R ^{96 to} R ¹⁰¹ each represents an electron-withdrawing substituent. R ¹⁰² represents either hydrogen or an alkyl group having 1 to 4 carbon atoms. L is a monoanionic ligand having a beta diketone structure, a monoanionic bidentate chelate ligand having a carboxyl group, or a monoanionic bidentate chelate ligand having a phenolic hydroxyl group Represents one of the following. Here, the electron-withdrawing substituent is preferably a halogen group or a —CF ₃ group. In order to improve the chemical stability, it is particularly preferable to use a fluoro group among the halogen groups. In addition, the alkyl group having 1 to 4 carbon atoms is preferably any group selected from a methyl group, an ethyl group, an isopropyl group, and a sec-butyl group.

  In the organometallic complex represented by the general formulas (14), (16), and (18), L is selected from ligands represented by the following structural formulas (1) to (7). Any ligand is preferred. All of the ligands represented by the structural formulas (1) to (7) are monoanionic ligands.

  One embodiment of the present invention is a light-emitting element including an organometallic complex represented by any one of General Formulas (1) to (18). The light-emitting element includes a layer containing an organometallic complex represented by any one of the general formulas (1) to (18) between the electrodes, and the general formula (1) when a current flows between the electrodes. It is preferable that the organometallic complex represented by any one of general formula (18) emits light. Thus, a light-emitting element using the organometallic complex of the present invention as a light-emitting substance has high recombination efficiency and emits light efficiently.

  One embodiment of the present invention is a light-emitting device using light emission from a light-emitting element including an organometallic complex represented by any one of General Formulas (1) to (18) as a pixel or a light source. Thus, since the light-emitting element of the present invention emits light efficiently, a light-emitting device driven with low power consumption can be obtained by using the light-emitting element of the present invention.

  By implementing the present invention, an organometallic complex that can be used to manufacture a light-emitting element with high recombination efficiency can be obtained. By implementing the present invention, an organometallic complex that can emit phosphorescence and can be used to manufacture a light-emitting element that emits light efficiently can be obtained.

One aspect of the present invention is that among the organometallic complexes represented by the general formula (1), in particular, R ⁵ and R ⁶ are fluoro groups, R ³ is hydrogen or a methyl group, R ⁸ is hydrogen, and M is iridium (Ir ), N = 2. The ligand is preferably any one of an acetylacetonate ligand, a tetrakis (1-pyrazolyl) borate ligand, or a picolinate ligand.

  By implementing the present invention, a light-emitting element that has high recombination efficiency and emits light efficiently can be obtained. Further, by implementing the present invention, phosphorescence can be emitted, and a light-emitting element with particularly high internal quantum efficiency can be obtained. In addition, by implementing the present invention, a light-emitting element that can efficiently repeat excitation and emission even in a high-luminance region can be obtained.

  By implementing the present invention, a light-emitting device that emits light efficiently and can be driven with low power consumption can be obtained.

  Hereinafter, one embodiment of the present invention will be described. However, the present invention can be implemented in many different modes, and those skilled in the art can easily understand that the modes and details can be variously changed without departing from the spirit and scope of the present invention. Is done. Therefore, the present invention is not construed as being limited to the description of the embodiment.

(Embodiment 1)
As one embodiment of the present invention, organometallic complexes represented by Structural Formulas (8) to (55) can be given. However, this invention is not limited to what was described here.

The organometallic complex of the present invention described above easily captures electrons. This is thought to be because an electron-withdrawing substituent could be introduced into the ligand according to the present invention.
In addition, since the organometallic complex of the present invention easily captures electrons, the use of the organometallic complex of the present invention can increase the recombination efficiency of carriers and produce a light-emitting element that emits light efficiently.
In addition, by using the organometallic complex of the present invention, a light-emitting element that can efficiently repeat excitation and light emission even when light is emitted with high luminance can be manufactured. This is presumably because the use of the organometallic complex of the present invention makes it difficult for non-luminescent transitions to increase due to the excitation lifetime of the excited triplet state.

  Moreover, the organometallic complex of the present invention represented by any one of Structural Formula (8) to Structural Formula (31) is represented by the following synthetic scheme (a-1) to synthetic scheme (a-3). Obtained by various synthesis methods. A ligand containing an electron-withdrawing substituent is synthesized as in synthesis scheme (a-1). Then, the synthesized ligand containing an electron-withdrawing substituent is mixed with iridium chloride hydrochloride hydrate and coordinated to iridium as represented by the synthesis scheme (a-2). Furthermore, as represented by the synthesis scheme (a-3), a monoanionic ligand is coordinated to iridium.

Here, in Synthesis Scheme (a-1) to Synthesis Scheme (a-3), R ¹⁰³ and R ¹⁰⁴ each represent any of a fluoro group, a —CF ₃ group, a cyano group, and an alkoxycarbonyl group. R ¹⁰⁵ and R ¹⁰⁶ each represent hydrogen or a methyl group. L represents acetylacetone or picolinic acid.

Note that the method for synthesizing the organometallic complex of the present invention is not limited to those represented by the synthesis scheme (a-1) to the synthesis scheme (a-3). For example, in the ligand obtained in (a-1), with respect to a ligand in which both R ¹⁰⁵ and R ¹⁰⁶ are alkyl-substituted, first, the para-position of the phenyl group is substituted with an electron-withdrawing group. 3-Diphenyl-1,4-dihydropyrazine-5,6-dione is used as a raw material to form a dichloro body in which the 5- and 6-positions are chlorinated using POCl ₃ or the like, and the resulting dichloro body and an alkyl metal are obtained. Obtained by coupling. Further, by using a salt containing platinum such as potassium tetrachloroplatinate instead of iridium chloride hydrochloride hydrate, the organometallic complex of the present invention containing platinum as a central metal can also be obtained. Further, by using a ligand such as dimethyl malonate, salicylaldehyde, salicylideneamine, tetrapyrazolato boronate instead of acetylacetone or picolinic acid, structural formulas (2), (4) to (7 It is also possible to obtain an organometallic complex of the present invention containing a ligand represented by

  Further, the organometallic complex of the present invention represented by any one of structural formula (32) to structural formula (55) is represented by the following synthesis scheme (b-1) to synthesis scheme (b-3). Obtained by various synthesis methods. A ligand containing an electron-withdrawing substituent is synthesized as in synthesis scheme (b-1). Then, the synthesized ligand containing an electron-withdrawing substituent is mixed with iridium chloride hydrochloride hydrate and coordinated to iridium as represented by the synthesis scheme (b-2). Furthermore, as represented by the synthesis scheme (b-3), a monoanionic ligand is coordinated to iridium.

Here, in Synthesis Scheme (b-1) to Synthesis Scheme (b-3), R ^{107 to} R ¹¹⁰ each represent any of a fluoro group, a —CF ₃ group, a cyano group, and an alkoxycarbonyl group. R ¹¹¹ and R ¹¹² each represent hydrogen or a methyl group. L represents acetylacetone or picolinic acid. The diketone used in the reaction of the synthesis scheme (b-1) is a benzene Grignard reagent substituted with an electron-withdrawing substituent such as a fluoro group or —CF _{3 at the 3-} and 5-positions and 1,4- It can be obtained by reacting with dimethylpiperazine-2,3-dione.

  Note that the method for synthesizing the organometallic complex of the present invention is not limited to those represented by the synthesis scheme (b-1) to the synthesis scheme (b-3). Further, by using a salt containing platinum such as potassium tetrachloroplatinate instead of iridium chloride hydrochloride hydrate, the organometallic complex of the present invention containing platinum as a central metal can also be obtained. Further, by using a ligand such as dimethyl malonate, salicylaldehyde, salicylideneamine, tetrapyrazolatoboronate instead of acetylacetone or picolinic acid, structural formulas (2), (4) to (7 It is also possible to obtain an organometallic complex of the present invention containing a ligand represented by

(Embodiment 2)
An embodiment of a light-emitting element using the organometallic complex of the present invention as a light-emitting substance is described with reference to FIGS.

  FIG. 1 illustrates a light-emitting element having a light-emitting layer 163 between a first electrode 151 and a second electrode 152. The light emitting layer 163 is represented by any one of the general formulas (1), (3), (5), (7), (9), (11), (13), (15), and (17). Or an organometallic complex of the present invention comprising a structure represented by formula (2), (4), (6), (8), (10), (12), (14), (16), (18) The organometallic complex of this invention represented by either of these is contained.

  In addition to the light-emitting layer 163, a hole injection layer 161, a hole transport layer 162, an electron transport layer 164, an electron injection layer 165, and the like are also provided between the first electrode 151 and the second electrode 152. . In these layers, when a voltage is applied so that the potential of the first electrode 151 is higher than the potential of the second electrode 152, holes are injected from the first electrode 151 side and the second electrode 152. They are stacked so that electrons are injected from the side.

  In such a light-emitting element, holes injected from the first electrode 151 side and electrons injected from the second electrode 152 side are recombined in the light-emitting layer 163 to bring the organometallic complex into an excited state. To do. The excited organometallic complex of the present invention emits light when returning to the ground state. Thus, the organometallic complex of the present invention functions as a light emitting substance. Here, since the organometallic complex of the present invention has a property of easily capturing electrons, carrier recombination is performed efficiently. As a result, the light-emitting element of the present invention containing the organometallic complex of the present invention emits light efficiently.

  Here, the light emitting layer 163 is a layer containing the organometallic complex of the present invention. The light emitting layer 163 may be a layer formed only from the organometallic complex of the present invention. However, when concentration quenching occurs, the light emitting layer 163 includes a material having a larger energy gap than that of the light emitting material. A layer mixed so that the light-emitting substance is dispersed is preferable. By dispersing and including the organometallic complex of the present invention in the light-emitting layer 163, light emission can be prevented from being quenched due to concentration. Here, the energy gap refers to an energy gap between the LUMO level and the HOMO level.

There is no particular limitation on a substance used for bringing the organometallic complex of the present invention into a dispersed state, but 2,3-bis (4-diphenylaminophenyl) quinoxaline (abbreviation: TPAQn), 4,4′-bis [N— In addition to a compound having an arylamine skeleton such as (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: NPB), 4,4′-di (N-carbazolyl) biphenyl (abbreviation: CBP), 4,4 Carbazole derivatives such as', 4 ''-tri (N-carbazolyl) triphenylamine (abbreviation: TCTA), bis [2- (2-hydroxyphenyl) pyridinato] zinc (abbreviation: Znpp ₂ ), bis [2- Metal complexes such as (2-hydroxyphenyl) benzoxazolate] zinc (abbreviation: Zn (BOX) ₂ ) are preferable. One or two or more substances may be selected from these substances and mixed so that the organometallic complex of the present invention is in a dispersed state. Thus, the layer containing a plurality of compounds can be formed by using a co-evaporation method. Here, co-evaporation refers to a vapor deposition method in which raw materials are vaporized from a plurality of vapor deposition sources provided in one processing chamber, the vaporized raw materials are mixed in a gas phase state, and deposited on an object to be processed.

  There is no particular limitation on the first electrode 151 and the second electrode 152. Indium tin oxide (ITO), indium tin oxide containing silicon oxide, or indium oxide containing 2 to 20% zinc oxide can be used. In addition, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd ) Or the like. In addition to aluminum, an alloy of magnesium and silver, an alloy of aluminum and lithium, or the like can be used to form the first electrode 151. Note that there is no particular limitation on a method for forming the first electrode 151 and the second electrode 152, and the first electrode 151 and the second electrode 152 can be formed using, for example, a sputtering method or an evaporation method. Note that in order to extract emitted light to the outside, a film of indium tin oxide or the like, or silver, aluminum, or the like having a thickness of several nanometers to several tens of nanometers is formed. It is preferable to form one or both of the second electrodes.

Further, a hole transport layer 162 may be provided between the first electrode 151 and the light emitting layer 163 as shown in FIG. Here, the hole transport layer is a layer having a function of transporting holes injected from the first electrode 151 side to the light emitting layer 163. In this manner, by providing the hole transport layer 162, the distance between the first electrode 151 and the light-emitting layer 163 can be increased. As a result, due to the metal contained in the first electrode 151, It is possible to prevent the light emission from being quenched. The hole transport layer is preferably formed using a substance having a high hole transport property, and particularly preferably formed using a substance having a hole mobility of 1 × 10 ⁻⁶ cm ² / Vs or higher. Note that a substance having a high hole-transport property has a higher hole mobility than an electron, preferably a value of the ratio of the hole mobility to the electron mobility (= hole mobility / electron mobility). Is a substance larger than 100. Specific examples of a substance that can be used to form the hole-transporting layer 162 include 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: NPB), 4, 4′-bis [N- (3-methylphenyl) -N-phenylamino] biphenyl (abbreviation: TPD), 4,4 ′, 4 ″ -tris (N, N-diphenylamino) triphenylamine (abbreviation: TDATA), 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (abbreviation: MTDATA), 4,4′-bis {N- [4- ( N, N-di-m-tolylamino) phenyl] -N-phenylamino} biphenyl (abbreviation: DNTPD), 1,3,5-tris [N, N-di (m-tolyl) amino] benzene (abbreviation: m -MTDAB), 4,4 ', 4''- Li (N- carbazolyl) triphenylamine (abbreviation: TCTA), phthalocyanine _{(abbreviation:} H 2 Pc), copper phthalocyanine (abbreviation: CuPc), or vanadyl phthalocyanine (abbreviation: VOPc), and the like. Further, the hole transport layer 162 may be a layer having a multilayer structure formed by combining two or more layers formed using the above-described substances.

Further, an electron transport layer 164 may be provided between the second electrode 152 and the light emitting layer 163 as shown in FIG. Here, the electron transporting layer is a layer having a function of transporting electrons injected from the second electrode 152 to the light emitting layer 163. In this manner, by providing the electron transport layer 164, the distance between the second electrode 152 and the light-emitting layer 163 can be increased, and as a result, light is emitted due to the metal contained in the second electrode 152. Can be prevented from quenching. The electron transport layer is preferably formed using a substance having a high electron transport property, and particularly preferably formed using a substance having an electron mobility of 1 × 10 ⁻⁶ cm ² / Vs or higher. Note that a substance having a high electron-transport property has a higher electron mobility than holes, and preferably has a ratio of electron mobility to hole mobility (= electron mobility / hole mobility). It is a substance larger than 100. Specific examples of a substance that can be used for forming the electron-transport layer 164 include tris (8-quinolinolato) aluminum (abbreviation: Alq ₃ ), tris (4-methyl-8-quinolinolato) aluminum (abbreviation: Almq _3). ), Bis (10-hydroxybenzo [h] -quinolinato) beryllium (abbreviation: BeBq ₂ ), bis (2-methyl-8-quinolinolato) -4-phenylphenolato-aluminum (abbreviation: BAlq), bis [2- In addition to metal complexes such as (2-hydroxyphenyl) benzoxazolate] zinc (abbreviation: Zn (BOX) ₂ ), bis [2- (2-hydroxyphenyl) benzothiazolate] zinc (abbreviation: Zn (BTZ) ₂ ) 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (approximately) Name: PBD), 1,3-bis [5- (p-tert-butylphenyl) -1,3,4-oxadiazol-2-yl] benzene (abbreviation: OXD-7), 3- (4- tert-butylphenyl) -4-phenyl-5- (4-biphenylyl) -1,2,4-triazole (abbreviation: TAZ), 3- (4-tert-butylphenyl) -4- (4-ethylphenyl) -5- (4-biphenylyl) -1,2,4-triazole (abbreviation: p-EtTAZ), bathophenanthroline (abbreviation: BPhen), bathocuproin (abbreviation: BCP), 4,4-bis (5-methylbenzoxa) And sol-2-yl) stilbene (abbreviation: BzOs). Further, the electron transport layer 164 may be a layer having a multilayer structure formed by combining two or more layers formed using the substances described above.

Note that the hole-transport layer 162 and the electron-transport layer 164 may be formed using a bipolar substance in addition to the substances described above. A bipolar substance is the ratio of the mobility of one carrier to the mobility of the other carrier when the mobility of one of the electrons or holes is compared with the mobility of the other carrier. A substance having a value of 100 or less, preferably 10 or less. Examples of the bipolar substance include TPAQn, 2,3-bis {4- [N- (1-naphthyl) -N-phenylamino] phenyl} -dibenzo [f, h] quinoxaline (abbreviation: NPDiBzQn), and the like. It is done. Among bipolar substances, it is particularly preferable to use a substance having a hole and electron mobility of 1 × 10 ⁻⁶ cm ² / Vs or more. Alternatively, the hole transport layer 162 and the electron transport layer 164 may be formed using the same bipolar substance.

Furthermore, a hole injection layer 161 may be provided between the first electrode 151 and the hole transport layer 162 as shown in FIG. The hole injection layer 161 is a layer having a function of assisting injection of holes from the first electrode 151 to the hole transport layer 162. By providing the hole injection layer 161, the difference in ionization potential between the first electrode 151 and the hole transport layer 162 is reduced, and holes are easily injected. The hole injection layer 161 has a lower ionization potential than the material forming the hole transport layer 162 and has a higher ionization potential than the material forming the first electrode 151, or the hole transport layer 162. The first electrode 151 is preferably formed using a substance whose energy band is bent when a thin film having a thickness of 1 to 2 nm is provided between the first electrode 151 and the first electrode 151. Specific examples of a substance that can be used to form the hole-injection layer 161 include phthalocyanine-based compounds such as phthalocyanine (abbreviation: H ₂ Pc) and copper phthalocyanine (CuPC), or poly (ethylenedioxythiophene) / Examples thereof include a polymer such as a poly (styrenesulfonic acid) aqueous solution (PEDOT / PSS). That is, the hole injection layer 161 can be formed by selecting a material whose ionization potential in the hole injection layer 161 is relatively smaller than the ionization potential in the hole transport layer 162. Note that in the case where the hole-injection layer 161 is provided, the first electrode 151 is preferably formed using a substance having a high work function such as indium tin oxide.

  Further, an electron injection layer 165 may be provided between the second electrode 152 and the electron transport layer 164 as shown in FIG. Here, the electron injection layer 165 is a layer having a function of assisting injection of electrons from the second electrode 152 to the electron transport layer 164. By providing the electron injection layer 165, the difference in electron affinity between the second electrode 152 and the electron transport layer 164 is reduced, and electrons are easily injected. The electron-injection layer 165 is a substance having a higher electron affinity than the substance forming the electron-transport layer 164 and a lower electron affinity than the substance forming the second electrode 152, or the electron-transport layer 164 and the second transport layer 164. It is preferable to use a material whose energy band bends when it is provided as a 1-2 nm thin film between the electrode 152 and the electrode 152. Specific examples of a substance that can be used to form the electron injection layer 165 include alkali metal or alkaline earth metal, alkali metal fluoride, alkaline earth metal fluoride, alkali metal oxide, and alkaline earth. Examples thereof include inorganic substances such as metal oxides. In addition to inorganic substances, substances that can be used to form the electron transport layer 164 such as BPhen, BCP, p-EtTAZ, TAZ, and BzOs are also used for forming the electron transport layer 164 from these substances. By selecting a substance having a higher electron affinity than the substance, it can be used as a substance for forming the electron injection layer 165. That is, the electron injection layer 165 can be formed by selecting a substance that has an electron affinity relatively higher than that of the electron transport layer 164 in the electron injection layer 165. Note that in the case where the electron-injecting layer 165 is provided, the first electrode 151 is preferably formed using a substance having a low work function such as aluminum.

  In the light-emitting element of the present invention described above, the hole injection layer 161, the hole transport layer 162, the light-emitting layer 163, the electron transport layer 164, and the electron injection layer 165 are formed by an evaporation method, an inkjet method, or a coating method, respectively. Or any other method. Further, the first electrode 151 or the second electrode 152 may be formed by any method such as a sputtering method or an evaporation method.

  Further, a hole generation layer may be provided instead of the hole injection layer 161, or an electron generation layer may be provided instead of the electron injection layer 165.

  Here, the hole generation layer is a layer that generates holes. By mixing at least one substance selected from substances having a higher hole mobility than electrons and a substance having an electron accepting property with respect to a substance having a higher hole mobility than electrons, Alternatively, the hole generating layer can be formed by mixing at least one substance selected from bipolar substances and a substance that exhibits an electron accepting property with respect to the bipolar substance. Here, as a substance having a higher hole mobility than an electron, a substance similar to the substance that can be used to form the hole-transport layer 162 can be used. As for the bipolar substance, the bipolar substance described above such as TPAQn can be used. In addition, among substances having higher mobility of holes than electrons and bipolar substances, it is particularly preferable to use a substance containing triphenylamine in the skeleton. By using a substance containing triphenylamine in the skeleton, holes are more easily generated. As the substance exhibiting electron accepting properties, it is preferable to use a metal oxide such as molybdenum oxide, vanadium oxide, ruthenium oxide, or rhenium oxide.

The electron generating layer is a layer that generates electrons. Choose from bipolar substances by mixing substances that have higher electron mobility than holes and substances that exhibit electron donating properties for substances that have higher electron mobility than holes. The electron generating layer can be formed by mixing at least one of the above substances and a substance that exhibits an electron donating property with respect to the bipolar substance. Here, as a substance having higher electron mobility than holes, a substance similar to the substance that can be used to form the electron-transport layer 164 can be used. As for the bipolar substance, the bipolar substance described above such as TPAQn can be used. In addition, as a substance exhibiting electron donating property, a substance selected from alkali metals and alkaline earth metals, specifically lithium oxide (Li ₂ O), calcium oxide (CaO), sodium oxide ( At least one substance selected from Na ₂ O), potassium oxide (K ₂ O), magnesium oxide (MgO), and the like can also be used as the substance exhibiting electron donating properties. Further, an alkali metal fluoride, an alkaline earth metal fluoride, specifically, at least one substance selected from lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF ₂ ), and the like is also an electron. It can be used as a substance exhibiting donating properties. Further, at least one substance selected from alkali metal nitride, alkaline earth metal nitride, and the like, specifically, calcium nitride, magnesium nitride, and the like can also be used as the substance exhibiting electron donating properties.

  In the light emitting device of the present invention as described above, whether or not to provide a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer and the like is arbitrary, and the practitioner of the present invention appropriately determines Just choose. However, when a hole transport layer and an electron transport layer are provided, an effect of reducing the occurrence of quenching due to the metal contained in the electrode, the hole injection layer, the electron injection layer or the like can be obtained. . Further, by providing an electron injection layer, a hole injection layer, or the like, it is possible to obtain an effect that electrons or holes can be efficiently injected from the electrode.

(Embodiment 3)
Since the light-emitting element of the present invention using the organometallic complex of the present invention as a light-emitting substance emits light efficiently, a light-emitting device that operates with low power consumption can be obtained by using the light-emitting element of the present invention as a pixel. .

  In this embodiment, a circuit configuration and a driving method of a light-emitting device having a display function will be described with reference to FIGS.

  FIG. 2 is a schematic view of a light emitting device to which the present invention is applied as viewed from above. In FIG. 2, a pixel portion 6511, a source signal line driver circuit 6512, a write gate signal line driver circuit 6513, and an erase gate signal line driver circuit 6514 are provided over a substrate 6500. The source signal line drive circuit 6512, the write gate signal line drive circuit 6513, and the erase gate signal line drive circuit 6514 are each an FPC (flexible printed circuit) 6503 which is an external input terminal via a wiring group. Connected. The source signal line driver circuit 6512, the writing gate signal line driver circuit 6513, and the erasing gate signal line driver circuit 6514 receive a video signal, a clock signal, a start signal, a reset signal, and the like from the FPC 6503, respectively. . A printed wiring board (PWB) 6504 is attached to the FPC 6503. Note that the driver circuit portion is not necessarily provided over the same substrate as the pixel portion 6511 as described above. For example, an IC chip mounted on an FPC on which a wiring pattern is formed (TCP) or the like is used. It may be used and provided outside the substrate.

  In the pixel portion 6511, a plurality of source signal lines extending in the column direction are arranged side by side in the row direction. In addition, current supply lines are arranged side by side in the row direction. In the pixel portion 6511, a plurality of gate signal lines extending in the row direction are arranged side by side in the column direction. In the pixel portion 6511, a plurality of sets of circuits including light-emitting elements are arranged.

  FIG. 3 is a diagram illustrating a circuit for operating one pixel. The circuit illustrated in FIG. 3 includes a first transistor 901, a second transistor 902, and a light emitting element 903.

  Each of the first transistor 901 and the second transistor 902 is a three-terminal element including a gate electrode, a drain region, and a source region, and has a channel region between the drain region and the source region. Here, since the source region and the drain region vary depending on the structure and operating conditions of the transistor, it is difficult to limit which is the source region or the drain region. Therefore, in this embodiment, regions functioning as a source or a drain are referred to as a first electrode of a transistor and a second electrode of the transistor, respectively.

  The gate signal line 911 and the writing gate signal line driving circuit 913 are provided so as to be electrically connected or disconnected by a switch 918. The gate signal line 911 and the erasing gate signal line driver circuit 914 are provided so as to be electrically connected or disconnected by a switch 919. The source signal line 912 is provided so as to be electrically connected to either the source signal line driver circuit 915 or the power source 916 by the switch 920. The gate of the first transistor 901 is electrically connected to the gate signal line 911. The first electrode of the first transistor is electrically connected to the source signal line 912, and the second electrode is electrically connected to the gate electrode of the second transistor 902. The first electrode of the second transistor 902 is electrically connected to the current supply line 917, and the second electrode is electrically connected to one electrode included in the light-emitting element 903. Note that the switch 918 may be included in the write gate signal line driver circuit 913. The switch 919 may also be included in the erase gate signal line driver circuit 914. Further, the switch 920 may also be included in the source signal line driver circuit 915.

  There is no particular limitation on the arrangement of transistors, light-emitting elements, and the like in the pixel portion. For example, they can be arranged as shown in the top view of FIG. In FIG. 4, the first electrode of the first transistor 1001 is connected to the source signal line 1004, and the second electrode is connected to the gate electrode of the second transistor 1002. The first electrode of the second transistor is connected to the current supply line 1005, and the second electrode is connected to the electrode 1006 of the light emitting element. Part of the gate signal line 1003 functions as a gate electrode of the first transistor 1001.

  Next, a driving method will be described. FIG. 5 is a diagram for explaining the operation of a frame over time. In FIG. 5, the horizontal direction represents the passage of time, and the vertical direction represents the number of scanning stages of the gate signal line.

  When image display is performed using the light emitting device of the present invention, the screen rewriting operation is repeatedly performed during the display period. The number of rewrites is not particularly limited, but is preferably at least about 60 times per second so that a person viewing the image does not feel flicker. Here, a period during which one screen (one frame) is rewritten is referred to as one frame period.

As shown in FIG. 5, one frame is time-divided into four subframes 501, 502, 503, and 504 including a writing period 501a, 502a, 503a, and 504a and a holding period 501b, 502b, 503b, and 504b. . A light emitting element to which a signal for emitting light is given is in a light emitting state in the holding period. The ratio of the length of the holding period in each subframe is as follows: first subframe 501: second subframe 502: third subframe 503: fourth subframe 504 = 2 ³ : 2 ² : 2 ¹ : 2 ⁰ = 8: 4: 2: 1. As a result, 4-bit gradation can be expressed. However, the number of bits and the number of gradations are not limited to those described here. For example, eight subframes may be provided so that 8-bit gradation can be performed.

  An operation in one frame will be described. First, in the subframe 501, the write operation is performed in order from the first row to the last row. Therefore, the start time of the writing period differs depending on the row. From the row in which the writing period 501a ends, the storage period 501b is started in order. In the holding period, the light-emitting element to which a signal for emitting light is given is in a light-emitting state. Further, the processing proceeds to the next subframe 502 in order from the row in which the holding period 501b ends, and the writing operation is performed in order from the first row to the last row as in the case of the subframe 501. The above operation is repeated until the holding period 504b of the subframe 504, and the operation in the subframe 504 is completed. When the operation in the subframe 504 is completed, the process proceeds to the next frame. Thus, the accumulated time of the light emission in each subframe is the light emission time of each light emitting element in one frame. Various display colors having different brightness and chromaticity can be formed by changing the light emission time for each light emitting element and combining them in various ways within one pixel.

  When it is desired to forcibly end the holding period in the row that has already finished writing and has shifted to the holding period before the writing up to the last row is completed as in the subframe 504, after the holding period 504b. It is preferable to provide an erasing period 504c and control to forcibly enter a non-light emitting state. Then, the row that is forcibly set to the non-light emitting state is kept in the non-light emitting state for a certain period (this period is referred to as a non-light emitting period 504d). Then, immediately after the writing period of the last row is completed, the writing period of the next subframe (or frame) is started in order from the first row. Accordingly, it is possible to prevent the writing period of the subframe 504 and the writing period of the next subframe from overlapping.

  In this embodiment, the subframes 501 to 504 are arranged in order from the longest holding period. However, the subframes 501 to 504 are not necessarily arranged as in the present embodiment. For example, the subframes 501 to 504 may be arranged in order from the shortest holding period. Alternatively, a long holding period and a short holding period may be arranged at random. In addition, the subframe may be further divided into a plurality of frames. That is, the gate signal line may be scanned a plurality of times during the period when the same video signal is applied.

  Here, the operation of the circuit shown in FIG. 3 in the writing period and the erasing period will be described.

  First, the operation in the writing period will be described. In the writing period, the gate signal line 911 in the n-th row (n is a natural number) is electrically connected to the writing gate signal line driving circuit 913 via the switch 918 and is connected to the erasing gate signal line driving circuit 914. Is disconnected. The source signal line 912 is electrically connected to the source signal line driver circuit through the switch 920. Here, a signal is input to the gate of the first transistor 901 connected to the gate signal line 911 in the n-th row (n is a natural number), and the first transistor 901 is turned on. At this time, video signals are simultaneously input to the source signal lines from the first column to the last column. Note that the video signals input from the source signal lines 912 in each column are independent from each other. A video signal input from the source signal line 912 is input to the gate electrode of the second transistor 902 through the first transistor 901 connected to each source signal line. At this time, the light-emitting element 903 determines whether to emit light or not according to a signal input to the second transistor 902. For example, in the case where the second transistor 902 is a p-channel transistor, the light-emitting element 903 emits light by inputting a low level signal to the gate electrode of the second transistor 902. On the other hand, in the case where the second transistor 902 is an n-channel transistor, the light-emitting element 903 emits light when a high level signal is input to the gate electrode of the second transistor 902.

  Next, the operation in the erasing period will be described. In the erasing period, the gate signal line 911 in the n-th row (n is a natural number) is electrically connected to the erasing gate signal line driving circuit 914 via the switch 919, and is connected to the writing gate signal line driving circuit 913. Not connected. The source signal line 912 is electrically connected to the power source 916 through the switch 920. Here, a signal is input to the gate of the first transistor 901 connected to the gate signal line 911 in the n-th row, and the first transistor 901 is turned on. At this time, the erase signal is simultaneously input to the source signal lines from the first column to the last column. The erase signal input from the source signal line 912 is input to the gate electrode of the second transistor 902 through the first transistor 901 connected to each source signal line. At this time, a current input from the current supply line 917 to the light-emitting element 903 is blocked by a signal input to the second transistor 902. Then, the light emitting element 903 is forced to emit no light. For example, in the case where the second transistor 902 is a p-channel transistor, the light-emitting element 903 does not emit light when a high level signal is input to the gate electrode of the second transistor 902. On the other hand, in the case where the second transistor 902 is an n-channel transistor, the light emitting element 903 does not emit light by inputting a low level signal to the gate electrode of the second transistor 902.

  In the erasing period, for the nth row (n is a natural number), a signal for erasing is input by the operation as described above. However, as described above, the nth row may be an erasing period and the other row (mth row (m is a natural number)) may be a writing period. In such a case, it is necessary to input a signal for erasure to the n-th row and a signal for writing to the m-th row using the source signal line in the same column. It is preferable to operate as described above.

  The gate signal line 911 and the erasing gate signal line driving circuit 914 are immediately disconnected after the light emitting element 903 in the n-th row does not emit light by the operation in the erasing period described above. The switch 920 is switched to connect the source signal line 912 and the source signal line driver circuit 915. Then, the source signal line and the source signal line driver circuit 915 are connected, and the gate signal line 911 and the writing gate signal line driver circuit 913 are connected. Then, a signal is selectively input from the writing gate signal line driving circuit 913 to the m-th signal line, the first transistor is turned on, and the source signal line driving circuit 915 receives the final signal from the first column. A signal for writing is input to the source signal lines up to the column. By this signal, the m-th row light emitting element emits light or does not emit light.

  Immediately after the writing period for the m-th row is completed as described above, the erasing period for the (n + 1) -th row starts. For this purpose, the gate signal line 911 and the writing gate signal line driving circuit 913 are disconnected, and the switch 920 is switched to connect the source signal line to the power source 916. Further, the gate signal line 911 and the writing gate signal line driving circuit 913 are disconnected, and the gate signal line 911 is connected to the erasing gate signal line driving circuit 914. Then, a signal is selectively input from the erasing gate signal line driving circuit 914 to the gate signal line of the (n + 1) th row to turn on the signal to the first transistor, and an erasing signal is input from the power supply 916. In this way, immediately after the erasing period of the (n + 1) th row is completed, the writing period of the (m + 1) th row is started. Thereafter, similarly, the erasing period and the writing period may be repeated until the erasing period of the last row is operated.

  In this embodiment, the mode in which the m-th writing period is provided between the n-th erasing period and the (n + 1) -th erasing period has been described. An m-th writing period may be provided between the period and the n-th erasing period.

  Further, in this embodiment, when the non-light emission period 504d is provided as in the subframe 504, the erasing gate signal line driver circuit 914 and a certain gate signal line are brought into a non-connected state, and writing is performed. The operation of connecting the gate signal line driving circuit 913 and the other gate signal lines is repeated. Such an operation may be performed particularly in a frame in which a non-light emitting period is not provided.

(Embodiment 4)
One mode of a cross-sectional view of a light-emitting device including the light-emitting element of the present invention is described with reference to FIGS.

  In FIG. 6, a transistor 11 provided for driving the light emitting element 12 of the present invention is surrounded by a dotted line. The light-emitting element 12 includes a layer 15 in which a layer that generates holes, a layer that generates electrons, and a layer that contains a light-emitting substance are stacked between the first electrode 13 and the second electrode 14. It is a light emitting element. The drain of the transistor 11 and the first electrode 13 are electrically connected by a wiring 17 penetrating the first interlayer insulating film 16 (16a, 16b, 16c). The light emitting element 12 is separated from another light emitting element provided adjacent thereto by a partition wall layer 18. The light-emitting device of the present invention having such a structure is provided over the substrate 10 in this embodiment.

  Note that the transistor 11 illustrated in FIG. 6 is a top-gate transistor in which a gate electrode is provided on the opposite side of the substrate with a semiconductor layer as a center. However, the structure of the transistor 11 is not particularly limited, and may be, for example, a bottom gate type. In the case of a bottom gate, the semiconductor layer forming a channel may be formed with a protective film (channel protection type), or the semiconductor layer forming the channel may be partially concave ( Channel etch type).

  Further, the semiconductor layer included in the transistor 11 may be either crystalline or non-crystalline. Moreover, a semi-amorphous etc. may be sufficient.

The semi-amorphous semiconductor is as follows. A semiconductor having an intermediate structure between amorphous and crystalline (including single crystal and polycrystal) and having a third state that is stable in terms of free energy, has a short-range order, and has a lattice distortion. It contains a crystalline region. Further, at least a part of the region in the film contains crystal grains of 0.5 to 20 nm. The Raman spectrum is shifted to the lower wavenumber side than 520 cm ⁻¹ . In X-ray diffraction, diffraction peaks of (111) and (220) that are derived from the Si crystal lattice are observed. In order to terminate dangling bonds (dangling bonds), hydrogen or halogen is contained at least 1 atomic% or more. It is also called a so-called microcrystalline semiconductor (microcrystal semiconductor), and a gas selected from SiH ₄ , Si ₂ H ₆ , SiH ₂ Cl ₂ , SiHCl ₃ , SiCl ₄ , and SiF ₄ is subjected to glow discharge decomposition (plasma CVD). ) To form. These gases may be diluted with H ₂ , or H ₂ and one or more kinds of rare gas elements selected from He, Ar, Kr, and Ne. The dilution ratio is in the range of 2 to 1000 times, the pressure is in the range of approximately 0.1 Pa to 133 Pa, the power frequency is 1 MHz to 120 MHz, preferably 13 MHz to 60 MHz, and the substrate heating temperature may be 300 ° C. or less, preferably 100 to 250 ° C. As an impurity element in the film, impurities of atmospheric components such as oxygen, nitrogen, and carbon are desirably 1 × 10 ²⁰ / cm ³ or less, and in particular, the oxygen concentration is 5 × 10 ¹⁹ / cm ³ or less, preferably 1 × 10 ¹⁹ / cm ³ or less. Note that the mobility of a TFT (thin film transistor) using a semi-amorphous semiconductor is approximately 1 to 10 cm ² / Vsec.

  As a specific example of the crystalline semiconductor layer, a semiconductor layer formed using single crystal or polycrystalline silicon, silicon germanium, or the like can be given. These may be formed by laser crystallization, or may be formed by crystallization by a solid phase growth method using nickel or the like, for example.

  Note that in the case where the semiconductor layer is formed of an amorphous material, for example, amorphous silicon, the transistor 11 and other transistors (transistors constituting a circuit for driving a light emitting element) are all configured by N-channel transistors. It is preferable that the light-emitting device have a structured circuit. Other than that, a light-emitting device having a circuit including any one of an N-channel transistor and a P-channel transistor, or a light-emitting device including a circuit including both transistors may be used.

  Further, the first interlayer insulating film 16 may be a multilayer as shown in FIGS. 6A and 6C, or may be a single layer. Note that 16a is made of an inorganic material such as silicon oxide or silicon nitride, and 16b is acrylic or siloxane (a siloxane resin is a compound having a Si—O—Si bond as a main skeleton. Further, hydrogen or methyl An alkyl group such as a group as a substituent.), And a self-flattening substance such as silicon oxide that can be coated and formed. Further, 16c is formed using a silicon nitride film containing argon (Ar). In addition, there is no limitation in particular about the substance which comprises each layer, You may use things other than what was described here. Moreover, you may further combine the layer formed using substances other than these. As described above, the first interlayer insulating film 16 may be formed using both an inorganic material and an organic material, or may be formed of any one of an inorganic material and an organic material.

  The partition layer 18 preferably has a shape in which the radius of curvature continuously changes at the edge portion. The partition layer 18 is formed using acrylic, siloxane, resist, silicon oxide, or the like. The partition wall layer 18 may be formed of any one of an inorganic material and an organic material, or may be formed using both.

  In FIGS. 6A and 6C, only the first interlayer insulating film 16 is provided between the transistor 11 and the light emitting element 12, but as shown in FIG. 6B, the first interlayer insulating film 16 is provided. In addition to the insulating film 16 (16a, 16b), the second interlayer insulating film 19 (19a, 19b) may be provided. In the light emitting device shown in FIG. 6B, the first electrode 13 penetrates through the second interlayer insulating film 19 and is connected to the wiring 17.

  Similar to the first interlayer insulating film 16, the second interlayer insulating film 19 may be a multilayer or a single layer. 19a is formed using a self-flattening material such as acrylic, siloxane, or silicon oxide that can be coated and formed. Further, 19b is formed using a silicon nitride film containing argon (Ar). In addition, there is no limitation in particular about the substance which comprises each layer, You may use things other than what was described here. Moreover, you may further combine material layers other than these. As described above, the second interlayer insulating film 19 may be formed using both an inorganic material and an organic material, or may be formed using any one of an inorganic material and an organic material.

  In the light-emitting element 12, when both the first electrode and the second electrode are formed using a light-transmitting substance, the first electrode and the second electrode are represented by the white arrows in FIG. Light emission can be extracted from both the electrode 13 side and the second electrode 14 side. In addition, in the case where only the second electrode 14 is formed using a light-transmitting substance, light emission is extracted only from the second electrode 14 side as represented by a white arrow in FIG. 6B. be able to. In this case, the first electrode 13 is made of a highly reflective material, or a film (reflective film) formed using a highly reflective material is provided below the first electrode 13. It is preferable. In addition, in the case where only the first electrode 13 is formed using a light-transmitting substance, light emission is extracted only from the first electrode 13 side as represented by a white arrow in FIG. be able to. In this case, it is preferable that the second electrode 14 is made of a highly reflective material, or a reflective film is provided above the second electrode 14.

  In addition, the light emitting element 12 may be one in which the layer 15 is stacked so as to operate when a voltage is applied so that the potential of the second electrode 14 is higher than the potential of the first electrode 13. Alternatively, the layer 15 may be stacked so as to operate when a voltage is applied so that the potential of the second electrode 14 is lower than the potential of the first electrode 13. In the former case, the transistor 11 is an N-channel transistor, and in the latter case, the transistor 11 is a P-channel transistor.

  As described above, in this embodiment, the active light-emitting device in which the driving of the light-emitting element is controlled by the transistor has been described.

  However, the present invention may be applied not only to the active light-emitting device but also to a passive light-emitting device. In particular, a light-emitting element manufactured using the organometallic complex of the present invention and capable of efficiently repeating excitation and emission even in a high-luminance region is a passive type that needs to emit light with high luminance instantaneously. Suitable for use as a pixel of a light emitting device.

  FIG. 7 is a perspective view of a passive light emitting device manufactured by applying the present invention. In FIG. 7, an electrode 1902 and an electrode 1906 are provided between a substrate 1901 and a substrate 1907. The electrode 1902 and the electrode 1906 are provided so as to intersect. Further, a light emitting layer 1905 (indicated by a broken line so that the arrangement of 1902, 1904, etc. can be seen) is provided between the electrode 1902 and the electrode 1906. Note that a hole-transport layer, an electron-transport layer, or the like may be provided between the light-emitting layer 1905 and the electrode 1902 or between the light-emitting layer 1905 and the electrode 1906. A partition layer 1904 is provided so as to cover an end portion of the electrode 1902. In FIG. 7, the partition wall layer 1904 is partially omitted. In this manner, the barrier rib layer 1904 is covered. A passive light emitting device can also be driven with low power consumption by including the light emitting element of the present invention that operates at a low driving voltage.

(Embodiment 5)
Since a light-emitting device including the light-emitting element of the present invention can be operated with a low driving voltage, an electronic device with low power consumption can be obtained with the electronic device of the present invention.

  One embodiment of an electronic device mounted with a light emitting device to which the present invention is applied is shown in FIG.

  FIG. 8A illustrates a laptop personal computer manufactured by applying the present invention, which includes a main body 5521, a housing 5522, a display portion 5523, a keyboard 5524, and the like. A personal computer can be completed by incorporating a light-emitting device having the light-emitting element of the present invention as a display portion.

  FIG. 8B illustrates a telephone manufactured by applying the present invention. The main body 5552 includes a display portion 5551, an audio output portion 5554, an audio input portion 5555, operation switches 5556 and 5557, an antenna 5553, and the like. ing. A telephone can be completed by incorporating a light-emitting device having the light-emitting element of the present invention as a display portion.

  FIG. 8C illustrates a television set manufactured by applying the present invention, which includes a display portion 5531, a housing 5532, a speaker 5533, and the like. A television receiver can be completed by incorporating a light-emitting device having the light-emitting element of the present invention as a display portion.

  As described above, the light-emitting device of the present invention is very suitable for use as a display portion of various electronic devices.

  Note that although a personal computer, a telephone, and the like are described in this embodiment, a light-emitting device having the light-emitting element of the present invention may be mounted on a navigation device or a camera.

[Synthesis Example 1]
A synthesis method of the organometallic complex of the present invention represented by the structural formula (8) (name: (acetylacetonato) bis [2,3-bis (4-fluorophenyl) pyrazinato] iridium (III)) will be described.
[Step 1: Synthesis of Ligand (abbreviation: HFdppr)]
First, 1,4 g of 4,4′-difluorobenzyl (manufactured by Tokyo Chemical Industry Co., Ltd.) and 4.5 g of ethylenediamine (manufactured by Kanto Chemical Co., Ltd.) were mixed in a dehydrated ethanol solvent, and the mixture was refluxed at 105 ° C. for 6 hours. . After the reaction, the reaction solution was concentrated using an evaporator, and the resulting residue was recrystallized using ethanol to obtain 2,3-bis (4-fluorophenyl) -5,6-dihydropyrazine. (Reddish brown powder, 93% yield).
Next, in a three-necked flask equipped with a mechanical stirrer, 16.1 g of 2,3-bis (4-fluorophenyl) -5,6-dihydropyrazine obtained above and 5.6 g of potassium hydroxide were mixed. Further, 100 mL of glycerol was added as a solvent, and the mixture was stirred with heating at 190 ° C. for 10 hours. After the reaction, the reddish brown film deposited on the upper layer of glycerol was washed with water. The washed film was purified by column chromatography using a mixed solvent of hexane and ethyl acetate (hexane: ethyl acetate = 2: 1 by volume) as a developing solvent (R _f = 0.57). Further, 2.8 g of a ligand 2,3-bis (4-fluorophenyl) pyrazine (abbreviation: HFdppr) was obtained by recrystallization with ethanol (light yellow crystal, yield 17.5%). A synthesis scheme (c-1) relating to the synthesis of Step 1 is shown below.

[Step 2: Synthesis of a binuclear complex (abbreviation: [Ir (Fdppr) ₂ Cl] ₂ ))
Next, in a mixed solvent of 30 mL of 2-ethoxyethanol and 10 mL of water, 5.01 g of the ligand HFdppr obtained above and 1.01 g of iridium chloride hydrochloride hydrate (IrCl ₃ .HCl.H ₂ O) [manufactured by Aldrich] and the mixture was refluxed for 16 hours under a nitrogen atmosphere to obtain a binuclear complex [Ir (Fdppr) ₂ Cl] ₂ (red brown powder, 31% yield) . A synthesis scheme (c-2) relating to the synthesis of Step 2 is shown below.

[Step 3: Synthesis of Organometallic Complex of the Present Invention (abbreviation: [Ir (Fdppr) ₂ (acac)])]
Further, 0.76 g of [Ir (Fdppr) ₂ Cl] ₂ , 0.15 mL of acetylacetone (abbreviation: Hacac) and 0.53 g of sodium carbonate are mixed with 20 mL of 2-ethoxyethanol solvent, and the mixture is mixed. By refluxing in a nitrogen atmosphere for 17 hours, a yellow-orange powder was obtained (yield 16%). A synthesis scheme (c-3) relating to the synthesis of Step 3 is shown below.

When the obtained yellow-orange powder was analyzed by nuclear magnetic resonance spectroscopy ( ¹ H-NMR), the following results were obtained, which is one of the organometallic complexes of the present invention and represented by the structural formula (8). Ir (Fdppr) ₂ (acac). Moreover, the chart of ¹ H-NMR is shown in FIG.

¹ H-NMR. δ (CDCl ₃ ): 8.38 (dd, 4H), 7.69 (dd, 4H), 7.23 (m, 4H), 6.89 (dd, 2H), 6.29 (td, 2H) , 5.95 (dd, 2H), 5.31 (s, 1H), 1.89 (s, 6H)

Moreover, when the decomposition temperature _Td of the obtained organometallic complex Ir (Fdppr) ₂ (acac) of the present invention was measured by a differential thermothermal gravimetric simultaneous measurement apparatus (TG / DTA 320 type, manufactured by Seiko Electronics Co., Ltd.), T It was found that _d = 312 ° C. and good heat resistance was exhibited.

Next, with Ir (Fdppr) ₂ (acac) dissolved in dichloromethane, the absorption spectrum of Ir (Fdppr) ₂ (acac) at room temperature (UV550 spectrophotometer, model V550 manufactured by JASCO Corporation) and emission spectrum ( Fluorophotometer FS920 manufactured by Hamamatsu Photonics Co., Ltd. was measured. The results are shown in FIG. In FIG. 10, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit). As can be seen from FIG. 10, the absorption spectrum of the organometallic complex Ir (Fdppr) ₂ (acac) of the present invention has peaks at 380 nm, 420 nm, 490 nm and 525 nm. In addition, the emission spectrum of Ir (Fdppr) ₂ (acac) had a peak at 570 nm and emitted yellow light.

Also, it injected Ir _(Fdppr) gas containing oxygen to a dichloromethane solution containing 2 (acac), was examined emission intensity when made to emit light Ir _(Fdppr) 2 _(acac) in a state in which oxygen was dissolved. Also, argon was injected into a dichloromethane solution containing Ir _(Fdppr) 2 _(acac), it was examined emission intensity when made to emit light Ir _(Fdppr) 2 _(acac) with dissolved argon. As a result, the light emission derived from Ir (Fdppr) ₂ (acac) has a tendency similar to that of a substance that emits phosphorescence, in which the light emission intensity in the state in which argon is dissolved is stronger than the light emission intensity in the state in which oxygen is dissolved. It was found that From this, it was confirmed that light emission derived from Ir (Fdppr) ₂ (acac) was phosphorescence.

[Synthesis Example 2]
Synthesis Method of Organometallic Complex of the Present Invention Represented by Structural Formula (16) (name: (acetylacetonato) bis [2,3-bis (4-fluorophenyl) -5-methylpyrazinato] iridium (III)) explain.
[Step 1: Synthesis of Ligand (abbreviation: HFdppr-Me)]
First, 5.31 g of 4,4′-difluorobenzyl [manufactured by Tokyo Chemical Industry] and 1.60 g of 1,2-diaminopropane [manufactured by Tokyo Chemical Industry] are mixed in an ethanol solvent, and the mixture is refluxed for 3 hours. It was. After the reaction, the reaction solution is concentrated with an evaporator, and the obtained residue is recrystallized with ethanol to obtain 2,3-bis (4-fluorophenyl) -5-methyl-5,6-dihydropyrazine. (Light yellow powder, 86% yield).
Next, 5.29 g of 2,3-bis (4-fluorophenyl) -5-methyl-5,6-dihydropyrazine and 6.04 g of iron (III) chloride were mixed with ethanol as a solvent, The mixture was gently heated and stirred for 3 hours. The solid obtained by adding water to the solution after the reaction was purified by column chromatography using dichloromethane as a developing solvent, and the ligand 2,3-bis (4-fluorophenyl) -5-methylpyrazine (HFdppr). -Me) was obtained (milky white powder, yield 72%).
A synthesis scheme (d-1) relating to the synthesis of Step 1 is shown below.

[Step 2: Synthesis of Binuclear Complex (abbreviation: [Ir (Fdppr-Me) ₂ Cl] ₂ )]
Next, to a mixed solvent of 30 mL of 2-ethoxyethanol and 10 mL of water, 3.75 g of ligand HFdppr-Me and 1.59 g of iridium chloride hydrochloride hydrate (III) (IrCl ₃ .HCl.H ₂ O) [manufactured by Aldrich] and the mixture was refluxed for 16 hours under a nitrogen atmosphere to obtain a binuclear complex [Ir (Fdppr-Me) ₂ Cl] ₂ (red brown powder, yield) 87%).
A synthesis scheme (d-2) relating to the synthesis of Step 2 is shown below.

[Step 3: Synthesis of Organometallic Complex of the Present Invention (abbreviation: [Ir (Fdppr-Me) ₂ (acac)])]
Further, 1.91 g of [Ir (Fdppr-Me) ₂ Cl] ₂ , 0.37 mL of acetylacetone (Hacac) and 1.28 g of sodium carbonate were mixed in 30 mL of 2-ethoxyethanol solvent, and the mixture was mixed. By refluxing for 16 hours under a nitrogen atmosphere, a yellow-orange powder (yield 34%) was obtained.
A synthesis scheme (d-3) relating to the synthesis of Step 3 is shown below.

When the obtained yellow-orange powder was analyzed by nuclear magnetic resonance spectroscopy ( ¹ H-NMR), the following results were obtained, which is one of the organometallic complexes of the present invention and represented by the structural formula (16). Ir (Fdppr-Me) ₂ (acac).

¹ H-NMR. δ (CDCl ₃ ): 8.27 (s, 2H), 7.66 (dd, 4H), 7.22 (m, 4H), 6.78 (dd, 2H), 6.26 (td, 2H) , 5.92 (dd, 2H), 5.31 (s, 1H), 2.70 (s, 6H), 1.89 (s, 6H)
A ¹ H-NMR chart is shown in FIG. 11.

Moreover, when the decomposition temperature _Td of the obtained organometallic complex Ir (Fdppr-Me) ₂ (acac) of the present invention was measured by a differential thermothermal gravimetric simultaneous measurement apparatus (TG / DTA 320 type, manufactured by Seiko Electronics Co., Ltd.). , T _d = 291 ° C., showing good heat resistance.

Next, the absorption spectrum of Ir (Fdppr-Me) ₂ (acac) at room temperature in a state in which Ir (Fdppr-Me) ₂ (acac) is dissolved in dichloromethane (V550 model manufactured by JASCO Corporation) And an emission spectrum (fluorescence meter FS920 manufactured by Hamamatsu Photonics Co., Ltd.) were measured. The results are shown in FIG. In FIG. 12, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit). As can be seen from FIG. 12, the absorption spectrum of the organometallic complex Ir (Fdppr-Me) ₂ (acac) of the present invention has peaks at 380 nm, 420 nm, 485 nm and 520 nm. In addition, the emission spectrum of Ir (Fdppr-Me) ₂ (acac) had a peak at 564 nm and was yellow.

The light emitting intensity when injected Ir _(Fdppr-Me) gas containing oxygen to a dichloromethane solution containing 2 (acac), was made to emit light _{Ir (Fdppr-Me) 2 (} acac) with dissolved oxygen I investigated. Also, argon was injected into a dichloromethane solution containing _{Ir (Fdppr-Me) 2 (} acac) , was examined emission intensity when made to emit light _{Ir (Fdppr-Me) 2 (} acac) with dissolved argon . As a result, the light emission derived from Ir (Fdppr-Me) ₂ (acac) is similar to the phosphorescent substance in which the light emission intensity in the state in which argon is dissolved is stronger than the light emission intensity in the state in which oxygen is dissolved. It was found that this tendency was shown. From this, it was confirmed that light emission derived from Ir (Fdppr-Me) ₂ (acac) was phosphorescence.

[Synthesis Example 3]
The organometallic complex bis [2,3-bis (4-fluorophenyl) -5-methylpyrazinato] [tetrakis (1-pyrazolyl) borato] iridium (III) (abbreviation: Ir) represented by the structural formula (56) A method for synthesizing (Fdppr-Me) ₂ (bpz ₄ ) will be described.

First, 1.00 g of the binuclear complex [Ir (Fdppr-Me) ₂ Cl] ₂ obtained in Step 2 of Synthesis Example ₂ was suspended in 40 mL of dichloromethane. A solution obtained by dissolving 0.40 g of silver trifluoromethanesulfonate in 40 mL of a methanol solvent was dropped into the suspension. After dropping, the suspension was stirred at room temperature for 2 hours and further centrifuged. The supernatant obtained by centrifugation was separated by decantation and concentrated to dryness. Next, the solid obtained by concentration and drying to 30 mL of acetonitrile was mixed with 0.70 g of tetrakis (1-pyrazolyl) borate potassium salt (manufactured by Acros Organics), and the mixture was placed under a nitrogen atmosphere. And refluxed for 18 hours to obtain a yellow powder (yield 50%).
A synthesis scheme (e) of this synthesis is shown below.

When the obtained yellow powder was analyzed by nuclear magnetic resonance spectroscopy ( ¹ H-NMR), the following results were obtained, which is one of the organometallic complexes of the present invention and represented by the structural formula (56). Ir (Fdppr-Me) ₂ (bpz ₄ ).

¹ H-NMR. δ (CDCl ₃ ): 7.73 (m, 2H), 7.53 (m, 4H), 7.24-7.18 (m, 5H), 7.03 (s, 2H), 6.94 ( m, 2H), 6.81 (dd, 2H), 6.41-6.26 (m, 7H), 6.08 (m, 2H), 5.88 (dd, 2H), 2.43 (s , 6H).
^{The 1} H-NMR chart is shown in FIG.

Further, the organometallic complex Ir _(Fdppr-Me) of the present invention obtained 2 (bpz ₄₎ of the decomposition temperature _{T d} of TG / DTA (differential thermogravimetric simultaneous analysis device Seiko Electronics Co., Ltd. TG / DTA 320 type) As a result of measurement, it was found that T _d = 330 ° C. and good heat resistance was exhibited.

Next, the absorption spectrum and emission spectrum of Ir (Fdppr-Me) ₂ (bpz ₄ ) were measured at room temperature using a degassed dichloromethane solution. The absorption spectrum was measured using an ultraviolet-visible spectrophotometer (V550 type manufactured by JASCO Corporation), and the emission spectrum was measured using a fluorometer (FS920 manufactured by Hamamatsu Photonics Co., Ltd.). The results are shown in FIG. In FIG. 24, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit). As can be seen from FIG. 24, the organometallic complex Ir (Fdppr-Me) ₂ (bpz ₄ ) of the present invention has absorption peaks at 273 nm, 334 nm, 403 nm and 446 nm. In addition, the emission spectrum of Ir (Fdppr-Me) ₂ (bpz ₄ ) had an emission peak at 553 nm and emitted yellowish green light.

[Synthesis Example 4]
Organometallic complex bis [2,3-bis (4-fluorophenyl) -5-methylpyrazinato] (picolinato) iridium (III) represented by the structural formula (28) (abbreviation: Ir (Fdppr-Me) ₂ A method for synthesizing (pic) will be described.

First, 2.31 g of the binuclear complex [Ir (Fdppr-Me) ₂ Cl] ₂ obtained in Step 2 of Synthesis Example 2 and picolinic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) were added to 40 mL of 2-ethoxyethanol solvent. 1.33 g was mixed, and the mixture was refluxed for 20 hours under a nitrogen atmosphere to obtain a yellow powder (yield 91%).
A synthesis scheme (f) of this synthesis is shown below.

When the obtained yellow powder was analyzed by magnetic resonance spectroscopy ( ¹ H-NMR), the following results were obtained, which is one of the organometallic complexes of the present invention and represented by the structural formula (28). It was found to be Ir (Fdppr-Me) ₂ (pic).

¹ H-NMR. δ (CDCl ₃ ): 8.60 (s, 1H), 8.44 (d, 1H), 8.05 (td, 1H), 7.74 (d, 1H), 7.65-7.49 ( m, 5H), 7.31-7.15 (m, 5H), 6.88-6.79 (m, 2H), 6.39 (td, 1H), 6.31 (td, 1H), 6 .08 (dd, 1H), 5.83 (dd, 1H), 2.65 (s, 3H), 2.45 (s, 3H).
^{The 1} H-NMR chart is shown in FIG.

In addition, the decomposition temperature T _d of the obtained organometallic complex Ir (Fdppr-Me) ₂ (pic) of the present invention was determined by TG / DTA (TG / DTA 320 type, manufactured by Seiko Electronics Co., Ltd.). When measured, it was found that T _d = 346 ° C. and good heat resistance was exhibited.

Next, the absorption spectrum and emission spectrum of Ir (Fdppr-Me) ₂ (pic) were measured at room temperature using a degassed dichloromethane solution. The absorption spectrum was measured using an ultraviolet-visible spectrophotometer (V550 type manufactured by JASCO Corporation), and the emission spectrum was measured using a fluorometer (FS920 manufactured by Hamamatsu Photonics Co., Ltd.). The results are shown in FIG. In FIG. 26, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit). As can be seen from FIG. 26, the organometallic complex Ir (Fdppr-Me) ₂ (pic) of the present invention has absorption peaks at 330 nm, 360 nm, 410 nm, 455 nm and 505 nm. In addition, the emission spectrum of Ir (Fdppr-Me) ₂ (pic) had an emission peak at 558 nm and was yellow.

[Synthesis Example 5]
The organometallic complex bis [2,3-bis (2) of the present invention, which is an organometallic complex represented by any one of the general formulas (1) to (18) and more specifically represented by the structural formula (57) A method for synthesizing 4-fluorophenyl) -5-isopropylpyrazinato] (picolinato) iridium (III) (abbreviation: Ir (Fdppr-iPr) ₂ (pic)) will be described.

[Step 1: Synthesis of Ligand (abbreviation: HFdppr-iPr)]
First, 5.36 g of 4,4′-difluorobenzyl (manufactured by Tokyo Chemical Industry Co., Ltd.) and 1.31 g of anhydrous ethylenediamine [manufactured by Tokyo Chemical Industry Co., Ltd.] are mixed in 150 mL of dehydrated ethanol, The mixture was refluxed for 3 hours under a nitrogen atmosphere. The reaction solution was allowed to cool to room temperature, 1.60 g of acetone and 1.47 g of potassium hydroxide were added, and the solution was refluxed for 6 hours under a nitrogen atmosphere. After the reaction, water was added to the reaction solution, and extraction was performed using ethyl acetate. The organic layer obtained by extraction was dried over sodium sulfate and filtered, and then the solvent of the filtrate was distilled off. By purifying the obtained residue by silica gel column chromatography using dichloromethane as a developing solvent, 4.00 g of 2,3-bis (4-fluorophenyl) -5-isopropylpyrazine (HFdppr-iPr) which is a ligand. (Light yellow oil, yield 59%) was obtained. A synthesis scheme (g-1) relating to the synthesis of Step 1 is shown below.

[Step 2: Synthesis of a binuclear complex (abbreviation: [Ir (Fdppr-iPr) ₂ Cl] ₂ ))
Next, in a mixed solvent obtained by mixing 30 mL of 2-ethoxyethanol and 10 mL of water, 4.00 g of the ligand HFdppr-iPr obtained in Step 1 above, iridium (III) chloride hydrate (IrCl _3. 1.61 g of H ₂ O) [manufactured by Aldrich] was mixed, and the mixture was refluxed for 19 hours under a nitrogen atmosphere to obtain a binuclear complex [Ir (fdppr-iPr) ₂ Cl] ₂ (orange powder) , Yield 72%). A synthesis scheme (g-2) relating to the synthesis of Step 2 is shown below.

[Step 3: Synthesis of Organometallic Complex of the Present Invention (abbreviation: Ir (Fdppr-iPr) ₂ (pic))]
Furthermore, 1.61 g of the binuclear complex [Ir (Fdppr-iPr) ₂ Cl] ₂ obtained in Step 2 above and 0.94 g of picolinic acid were mixed with 25 mL of dichloromethane, and the mixture was mixed under a nitrogen atmosphere for 18 hours. A reflux color powder was obtained by refluxing (yield 90%). A synthesis scheme (g-3) relating to the synthesis of Step 3 is shown below.

When the obtained bright yellow powder was analyzed by nuclear magnetic resonance spectroscopy ( ¹ H-NMR), the following results were obtained, which is one of the organometallic complexes of the present invention and represented by the structural formula (57). It was found that Ir (Fdppr-iPr) ₂ (pic). A ¹ H-NMR chart is shown in FIG. 32.

¹ H-NMR. δ (CDCl ₃ ): 1.15 (d, 6H), 1.32 (t, 6H), 2.93 (quin, 1H), 3.16 (quin, 1H), 5.82 (dd, 1H) , 6.07 (dd, 1H), 6.31 (td, 1H), 6.38 (td, 1H), 6.85 (dd, 1H), 6.92 (dd, 1H), 7.11- 7.32 (m, 5H), 7.53 (m, 1H), 7.59-7.69 (m, 4H), 7.80 (d, 1H), 8.05 (td, 1H), 8 .43 (d, 1H), 8.60 (s, 1H).

In addition, the decomposition temperature _Td of the obtained organometallic complex Ir (Fdppr-iPr) ₂ (pic) of the present invention was determined by TG / DTA (TG / DTA 320 type, manufactured by Seiko Electronics Co., Ltd.). When measured, it was found that T _d = 348 ° C. and good heat resistance was exhibited.

Next, the absorption spectrum and emission spectrum of Ir (Fdppr-iPr) ₂ (pic) were measured at room temperature using a degassed dichloromethane solution. The absorption spectrum was measured using an ultraviolet-visible spectrophotometer (V550 type manufactured by JASCO Corporation), and the emission spectrum was measured using a fluorometer (FS920 manufactured by Hamamatsu Photonics Co., Ltd.). The results are shown in FIG. In FIG. 33, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit). As can be seen from FIG. 33, the organometallic complex Ir (Fdppr-iPr) ₂ (pic) of the present invention has absorption peaks at 328 nm, 410 nm, 453 nm and 509 nm. The emission spectrum was yellow emission having an emission peak at 559 nm.

[Synthesis Example 6]
Organometallic complex Ir (CF ₃ dppr-Me) ₂ (pic) represented by the structural formula (29) (name: bis [2,3-bis (4-trifluoromethylphenyl) pyrazinato] (picolinato) A method for synthesizing iridium (III) will be described.

[Step 1: Synthesis of Ligand (CF ₃ DPPR-Me)]
First, 5.07 g of 4,4′-bis (trifluoromethyl) benzyl and 1.09 g of 1,2-diaminopropane were mixed in 150 mL of dehydrated ethanol, and the mixture was refluxed for 4 hours in a nitrogen atmosphere. . After the reaction, the reaction solution was concentrated under reduced pressure, and the resulting residue was recrystallized with ethanol to obtain 2-methyl-5,6-bis (4-trifluoromethylphenyl) -2,3-dihydropyrazine. (Pale yellow crystals, yield 87%). Furthermore, 5.05 g of the 2-methyl-5,6-bis (4-trifluoromethylphenyl) -2,3-dihydropyrazine obtained above and iron (III) chloride were added to 100 mL of dehydrated ethanol. 26 g was mixed and the mixture was gently heated under a nitrogen atmosphere for 2 hours. After the reaction, the reaction solution was diluted with water and extracted with ether. The extract was dried over magnesium sulfate and filtered, and then the solvent was distilled off. The obtained residue was recrystallized with ethanol to obtain 5-methyl-2,3-bis (4-trifluoromethylphenyl) pyrazine (CF ₃ DPPR-Me) as a ligand (white powder) Yield 52%). A synthesis scheme (h-1) relating to the synthesis of Step 1 is shown below.

[Step 2: Synthesis of Binuclear Complex ([Ir (CF ₃ dppr-Me) ₂ Cl] ₂ )]
Next, 1.89 g of the ligand CF ₃ DPPR-Me obtained in Step 1 above, iridium (III) chloride hydrate (in a mixed solvent obtained by mixing 30 mL of 2-ethoxyethanol and 10 mL of water ( 0.83 g of IrCl ₃ · H ₂ O) [manufactured by Aldrich] was mixed, and the mixture was refluxed for 16 hours under a nitrogen atmosphere to obtain a binuclear complex [Ir (CF ₃ dppr-Me) ₂ Cl] ₂ . (Orange powder, 47% yield). A synthesis scheme (h-2) relating to the synthesis of Step 2 is shown below.

[Step 3: Synthesis of organometallic complex of the present invention (Ir (CF ₃ dppr-Me) ₂ (pic))]
Furthermore, 1.29 g of the binuclear complex [Ir (cf ₃ dppr-Me) ₂ Cl] ₂ obtained in Step 2 above and 0.64 g of picolinic acid were mixed with 30 mL of dichloromethane, and the mixture was stirred for 17 hours under a nitrogen atmosphere. A reflux color powder was obtained by refluxing (yield 47%). A synthesis scheme (h-3) relating to the synthesis of Step 3 is shown below.

When the obtained bright yellow powder was analyzed by nuclear magnetic resonance spectroscopy ( ¹ H-NMR), the following results were obtained, which is one of the organometallic complexes of the present invention and represented by the structural formula (29). Ir (CF ₃ dppr-Me) ₂ (pic). A chart of ¹ H-NMR is shown in FIG.

¹ H-NMR. δ (CDCl ₃ ): 2.53 (s, 1H), 2.71 (s, 1H), 6.34 (s, 1H), 6.63 (s, 1H), 6.82-6.96 ( m, 4H), 7.29 (m, 1H), 7.55 (m, 1H), 7.68-7.82 (m, 9H), 8.10 (td, 1H), 8.50 (d , 1H), 8.73 (s, 1H).

Further, the decomposition temperature T _d of the obtained organometallic complex Ir (CF ₃ dppr-Me) ₂ (pic) of the present invention is changed to TG / DTA (differential thermothermal gravimetric simultaneous measurement device TG / DTA 320 type manufactured by Seiko Electronics Co., Ltd.). ) Was found to be T _d = 338 ° C., indicating good heat resistance.

Next, the absorption spectrum and emission spectrum of Ir (CF ₃ dppr-Me) ₂ (pic) were measured at room temperature using a degassed dichloromethane solution. The absorption spectrum was measured using an ultraviolet-visible spectrophotometer (V550 type manufactured by JASCO Corporation), and the emission spectrum was measured using a fluorometer (FS920 manufactured by Hamamatsu Photonics Co., Ltd.). The results are shown in FIG. In FIG. 44, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit). As can be seen from FIG. 44, the organometallic complex Ir (CF ₃ dppr-Me) ₂ (pic) of the present invention has absorption peaks at 330 nm, 376 nm, 422 nm, 483 nm and 520 nm. The emission spectrum was yellow emission having an emission peak at 566 nm.

In this example, a method for manufacturing a light-emitting element using Ir (Fdppr) ₂ (acac) synthesized by the method described in Synthesis Example 1 as a light-emitting substance and operation characteristics of the light-emitting element will be described.

  As shown in FIG. 13, indium tin oxide containing silicon oxide was formed over a glass substrate 301 by a sputtering method, so that a first electrode 302 was formed. The thickness of the first electrode 302 was set to 110 nm. The electrodes were formed to have a square shape with a size of 2 mm × 2 mm.

  Next, the glass substrate 301 on which the first electrode 302 was formed was fixed to a holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward.

Next, after evacuating the vacuum apparatus and reducing the pressure to 1 × 10 ⁻⁴ Pa, a first layer 303 made of copper phthalocyanine was formed on the first electrode 302 by vapor deposition. The thickness of the first layer 303 was set to 20 nm. The first layer 303 is a layer that functions as a hole injection layer when the light emitting element is operated.

  Next, a second layer 304 was formed on the first layer 303 by vapor deposition using NPB. The thickness of the second layer 304 was set to 40 nm. The second layer 304 is a layer that functions as a hole transport layer when the light emitting element is operated.

Next, a third layer 305 containing CBP and Ir (Fdppr) ₂ (acac) was formed over the second layer 304 by a co-evaporation method. The thickness of the third layer 305 is 40 nm, and the mass ratio between CBP and Ir (Fdppr) ₂ (acac) is 1: 0.05 = CBP: Ir (Fdppr) ₂ (acac). did. As a result, Ir (Fdppr) ₂ (acac) is in a state where it is dispersed in a layer formed using CBP. The third layer 305 functions as a light emitting layer when the light emitting element is operated.

  Next, a fourth layer 306 was formed over the third layer 305 by vapor deposition using BCP. The thickness of the fourth layer 306 was set to 20 nm. The fourth layer 306 transports electrons to the third layer 305 functioning as a light-emitting layer when the light-emitting element is operated, and holes injected from the first electrode 302 side are in a third state. A function to prevent the layer 305 from penetrating to the other electrode side, and to prevent the excitation energy generated in the third layer 305 from moving from the third layer 305 to another layer It is a layer having the function of The layer having such a function is also called a hole blocking layer or simply a blocking layer.

Next, a fifth layer 307 was formed on the fourth layer 306 using Alq ₃ by an evaporation method. The thickness of the fifth layer 307 was set to 20 nm. The fifth layer 307 functions as an electron transport layer when the light emitting element is operated.

  Next, a sixth layer 308 was formed over the fifth layer 307 by vapor deposition using calcium fluoride. The thickness of the sixth layer 308 was set to 1 nm. The sixth layer 308 functions as an electron injection layer when the light emitting element is operated.

  Next, the second electrode 309 was formed over the sixth layer 308 using aluminum. The thickness of the second electrode 309 was set to 200 nm.

In the light-emitting element manufactured as described above, a current flows when a voltage is applied so that the potential of the first electrode 302 is higher than the potential of the second electrode 309, and the third element functions as a light-emitting layer. In the layer 305, electrons and holes are recombined to generate excitation energy, and light is emitted when the excited Ir (Fdppr) ₂ (acac) returns to the ground state. Note that a layer functioning as a blocking layer may be provided as in this embodiment. As a result, the transfer of excitation energy from the light emitting layer to other layers and the penetration of holes from the light emitting layer to other layers can be suppressed, and a light emitting element that emits light more efficiently can be obtained. .

  After the light emitting element was sealed in a glove box (sealing apparatus) in a nitrogen atmosphere so that the light emitting element was not exposed to the air, the operating characteristics of the light emitting element were measured. The measurement was performed at room temperature (atmosphere kept at 25 ° C.).

The measurement results are shown in FIGS. FIG. 14 shows the results of the current density-luminance characteristics, FIG. 15 shows the results of the voltage-luminance characteristics, and FIG. 16 shows the results of the brightness-current efficiency characteristics. In FIG. 14, the horizontal axis represents current density (mA / cm ² ), and the vertical axis represents luminance (cd / m ² ). In FIG. 15, the horizontal axis represents voltage (V) and the vertical axis represents luminance (cd / m ² ). In FIG. 16, the horizontal axis represents luminance (cd / m ² ) and the vertical axis represents current efficiency (cd / A). From these results, the light-emitting element manufactured in this example has a current density of 0.887 mA / cm ² when a voltage of 8.8 V is applied, and emits light with a luminance of 520 cd / m ^2. I understood. The current efficiency when emitting light with a luminance of 520 cd / m ² was 58 cd / A, which was 17% when converted into external quantum efficiency (= number of photons / number of electrons). Usually, it is said that the theoretical limit of the external quantum efficiency of a light emitting device manufactured on a glass substrate is about 20%. This shows that the light emitting element of this example emits light very efficiently. Thus, by applying the laminated structure as in Example 2, the organometallic complex of the present invention can be made to emit light efficiently and with high color purity. Further, from FIG. 16, the light emitting element of this example has very little change in current efficiency with respect to luminance in the high luminance region of 100 to 1000 cd / m ² , and almost no decrease in current efficiency with increase in luminance is observed. It can be seen that this is a light emitting element that cannot be used. Such a phenomenon is that the light-emitting element of this embodiment does not easily increase non-luminescence transition due to the excitation lifetime of the excited triplet state even in a high luminance region, and can efficiently repeat excitation and emission. It means that it can be done.

  In addition, an emission spectrum of the light-emitting element manufactured in this example is shown in FIG. In FIG. 17, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit). From FIG. 17, it was found that the light-emitting element of this example had a peak of the emission spectrum at 561 nm and exhibited yellow light emission. The emission spectrum had a very sharp spectral shape with a half-value width of 60 nm. Further, the chromaticity coordinates in the CIE color system are (x, y) = (0.48, 0.52), and it was found that the light emitting element of this example exhibits yellow with very good color purity.

In this example, a method for manufacturing a light-emitting element using Ir (Fdppr-Me) ₂ (acac) synthesized by the method described in Synthesis Example 2 as a light-emitting substance and operation characteristics of the light-emitting element will be described.

  As illustrated in FIG. 18, indium tin oxide containing silicon oxide was formed over a glass substrate 401 by a sputtering method, so that a first electrode 402 was formed. The thickness of the first electrode 402 was set to 110 nm. The electrodes were formed to have a square shape with a size of 2 mm × 2 mm.

  Next, the glass substrate 401 on which the first electrode 402 was formed was fixed to a holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward.

Next, the inside of the vacuum apparatus was evacuated and reduced in pressure to 1 × 10 ⁻⁴ Pa, and then a first layer 403 made of DNTPD was formed on the first electrode 402 by vapor deposition. The thickness of the first layer 403 was set to 50 nm. The first layer 403 functions as a hole injection layer when the light emitting element is operated.

  Next, a second layer 404 was formed on the first layer 403 by vapor deposition using NPB. The thickness of the second layer 404 was set to 10 nm. The second layer 404 is a layer that functions as a hole transport layer when the light emitting element is operated.

Next, a third layer 405 containing CBP and Ir (Fdppr-Me) ₂ (acac) was formed over the second layer 404 by a co-evaporation method. The thickness of the third layer 405 is set to 30 nm, and the mass ratio of CBP to Ir (Fdppr-Me) ₂ (acac) is 1: 0.025 = CBP: Ir (Fdppr-Me) ₂ (acac) It was made to become. As a result, Ir (Fdppr-Me) ₂ (acac) is dispersed in a layer formed using CBP. The third layer 405 functions as a light emitting layer when the light emitting element is operated.

  Next, a fourth layer 406 was formed on the third layer 405 by vapor deposition using BCP. The thickness of the fourth layer 406 was set to 20 nm. The fourth layer 406 functions as a blocking layer. The blocking layer is as described in the second embodiment.

Next, a fifth layer 407 was formed over the fourth layer 406 using Alq ₃ by an evaporation method. The thickness of the fifth layer 407 was set to 30 nm. The fifth layer 407 is a layer that functions as an electron transport layer when the light emitting element is operated.

  Next, a sixth layer 408 was formed on the fifth layer 407 by vapor deposition using calcium fluoride. The thickness of the sixth layer 408 was set to 1 nm. The sixth layer 408 functions as an electron injection layer when the light emitting element is operated.

  Next, a second electrode 409 was formed over the sixth layer 408 using aluminum. The thickness of the second electrode 409 was set to 200 nm.

In the light-emitting element manufactured as described above, a current flows when a voltage is applied so that the potential of the first electrode 402 is higher than the potential of the second electrode 409, and the third element functions as a light-emitting layer. In the layer 405, electrons and holes are recombined to generate excitation energy, and light is emitted when the excited Ir (Fdppr-Me) ₂ (acac) returns to the ground state.

  After the light emitting element was sealed in a glove box (sealing apparatus) in a nitrogen atmosphere so that the light emitting element was not exposed to the air, the operating characteristics of the light emitting element were measured. The measurement was performed at room temperature (atmosphere kept at 25 ° C.).

The measurement results are shown in FIGS. FIG. 19 shows the results of the current density-luminance characteristics, FIG. 20 shows the results of the voltage-luminance characteristics, and FIG. 21 shows the results of the brightness-current efficiency characteristics. In FIG. 19, the horizontal axis represents current density (mA / cm ² ), and the vertical axis represents luminance (cd / m ² ). In FIG. 20, the horizontal axis represents voltage (V) and the vertical axis represents luminance (cd / m ² ). In FIG. 21, the horizontal axis represents luminance (cd / m ² ) and the vertical axis represents current efficiency (cd / A). From these results, the light-emitting element manufactured in this example has a current density of 1.5 mA / cm ² when a voltage of 8.2 V is applied, and emits light with a luminance of 920 cd / m ^2. I understood. Note that the current efficiency when emitting light with a luminance of 920 cd / m ² was 61 cd / A, and 18% when converted to external quantum efficiency (= number of photons / number of electrons). This shows that the light emitting element of this example emits light very efficiently. Thus, by applying the laminated structure as in Example 3, the organometallic complex of the present invention can be made to emit light efficiently and with high color purity. Further, from FIG. 21, in the light emitting element of this example, in the high luminance region of 100 to 1000 cd / m ² , the change in current efficiency with respect to the luminance is very small, and the decrease in current efficiency with the increase in luminance is almost observed. It can be seen that this is a light emitting element that cannot be used. Such a phenomenon is that the light-emitting element of this embodiment does not easily increase non-luminescence transition due to the excitation lifetime of the excited triplet state even in a high luminance region, and can efficiently repeat excitation and emission. It means that it can be done.

  FIG. 22 shows an emission spectrum of the light-emitting element manufactured in this example. In FIG. 22, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit). From FIG. 22, it was found that the light-emitting element of this example had a peak of the emission spectrum at 557 nm and exhibited yellowish light emission. The emission spectrum had a sharp spectrum shape with a half-width of 80 nm. Further, the chromaticity coordinates in the CIE color system are (x, y) = (0.47, 0.52), and it was found that the light-emitting element of this example exhibits yellow with very good color purity.

In this example, a method for manufacturing a light-emitting element using Ir (Fdppr-Me) ₂ (bpz ₄ ) synthesized by the method described in Synthesis Example 3 as a light-emitting substance and operation characteristics of the light-emitting element will be described.

  As shown in FIG. 27, indium tin oxide containing silicon oxide was formed over a glass substrate 601 by a sputtering method, so that a first electrode 602 was formed. The thickness of the first electrode 602 was set to 110 nm. The electrodes were formed to have a square shape with a size of 2 mm × 2 mm.

  Next, the glass substrate 601 on which the first electrode 602 was formed was fixed to a holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward.

Next, after evacuating the vacuum apparatus and reducing the pressure to 1 × 10 ⁻⁴ Pa, a first layer 603 containing NPB and molybdenum oxide is formed on the first electrode 602 by vapor deposition. did. The thickness of the first layer 603 was 50 nm, and the mass ratio of NPB and molybdenum oxide was 4: 1 = NPB: molybdenum oxide. The thickness of the first layer 603 was set to 50 nm. The first layer 603 is a layer that functions as a hole injection layer when the light emitting element is operated.

  Next, a second layer 604 was formed on the first layer 603 by evaporation using NPB. The thickness of the second layer 604 was set to 10 nm. The second layer 604 functions as a hole transport layer when the light emitting element is operated.

Next, a third layer 605 containing CBP and Ir (Fdppr-Me) ₂ (bpz ₄ ) was formed over the second layer 604 by a co-evaporation method. The thickness of the third layer 605 is set to 30 nm, and the mass ratio of CBP to Ir (Fdppr-Me) ₂ (bpz ₄ ) is 1: 0.05 = CBP: Ir (Fdppr-Me) ₂ (bpz ₄ ). As a result, Ir (Fdppr-Me) ₂ (bpz ₄ ) is in a state of being dispersed in a layer using CBP. The third layer 605 functions as a light emitting layer when the light emitting element is operated.

  Next, a fourth layer 606 was formed on the third layer 605 by vapor deposition using BCP. The thickness of the fourth layer 606 was set to 20 nm. When the light emitting element is operated, the fourth layer 606 transports electrons to the third layer 605 functioning as a light emitting layer, and holes injected from the first electrode 602 side are transferred to the third layer 605. A function of preventing the layer 605 from penetrating to the other electrode side, and a suppression of movement of excitation energy generated in the third layer 605 from the third layer 605 to another layer It is a layer having the function of The layer having such a function is also called a hole blocking layer or simply a blocking layer.

  Next, a fifth layer 607 containing Alq and lithium (Li) was formed over the fourth layer 606 by an evaporation method. The thickness of the fifth layer 607 was 20 nm, and the mass ratio of Alq to lithium (Li) was 1: 0.01 = Alq: lithium (Li). The fifth layer 607 functions as an electron injection layer when the light emitting element is operated.

  Next, a second electrode 608 using aluminum was formed over the fifth layer 607. The thickness of the second electrode 608 was set to 200 nm.

In the light-emitting element manufactured as described above, a current flows when a voltage is applied so that the potential of the first electrode 602 is higher than the potential of the second electrode 608, and the third element functions as a light-emitting layer. In the layer 605, electrons and holes are recombined to generate excitation energy, and light is emitted when the excited Ir (Fdppr-Me) ₂ (bpz ₄ ) returns to the ground state. Note that a layer functioning as a blocking layer may be provided as in this embodiment. As a result, the transfer of excitation energy from the light emitting layer to other layers and the penetration of holes from the light emitting layer to other layers can be suppressed, and a light emitting element that emits light more efficiently can be obtained. .

  After the light emitting element was sealed in a glove box (sealing apparatus) in a nitrogen atmosphere so that the light emitting element was not exposed to the air, the operating characteristics of the light emitting element were measured. The measurement was performed at room temperature (atmosphere kept at 25 ° C.).

The measurement results are shown in FIGS. FIG. 28 shows the results of the current density-luminance characteristics, FIG. 29 shows the results of the voltage-luminance characteristics, and FIG. 30 shows the results of the brightness-current efficiency characteristics. In FIG. 28, the horizontal axis represents current density (mA / cm ² ), and the vertical axis represents luminance (cd / m ² ). In FIG. 29, the horizontal axis represents voltage (V) and the vertical axis represents luminance (cd / m ² ). In FIG. 30, the horizontal axis represents luminance (cd / m ² ) and the vertical axis represents current efficiency (cd / A). From these results, the light-emitting element manufactured in this example has a current density of 3.86 mA / cm ² when a voltage of 7.0 V is applied, and emits light with a luminance of 1210 cd / m ^2. I understood. Note that the current efficiency when emitting light at a luminance of 1210 cd / m ² was 31.4 cd / A, which was 9.34% when converted to external quantum efficiency (= number of photons / number of electrons). In addition, the maximum value of the external quantum efficiency was 11.8% when light was emitted at a luminance of 7.78 cd / m ² .

  In addition, an emission spectrum of the light-emitting element manufactured in this example is shown in FIG. In FIG. 31, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit). From FIG. 31, it was found that the light-emitting element of this example had a peak of emission spectrum at 556 nm and exhibited green-yellow light emission. Further, the chromaticity coordinates in the CIE color system are (x, y) = (0.42, 0.57), and it was found that the light-emitting element of this example exhibited a greenish yellow color.

In this example, a method for manufacturing a light-emitting element using Ir (Fdppr-Me) ₂ (pic) synthesized in Synthesis Example 4 as a light-emitting substance and operation characteristics of the light-emitting element will be described. Note that the light-emitting element manufactured in this example has a structure in which five layers are provided between the electrodes in the same manner as the light-emitting element manufactured in Example 4. Therefore, FIG. 27 is also used in the description of this embodiment.

  As shown in FIG. 27, indium tin oxide containing silicon oxide was formed over a glass substrate 601 by a sputtering method, so that a first electrode 602 was formed. The thickness of the first electrode 602 was set to 110 nm. The electrodes were formed to have a square shape with a size of 2 mm × 2 mm.

  Next, the glass substrate 601 over which the first electrode 602 was formed was fixed to a holder provided in a vacuum evaporation apparatus.

Next, after evacuating the vacuum apparatus and reducing the pressure to 1 × 10 ⁻⁴ Pa, NPB and molybdenum oxide (VI) are co-evaporated to oxidize NPB and molybdenum on the first electrode 602. A first layer 603 including a material was formed. The thickness of the first layer 603 was 40 nm, and the mass ratio of NPB and molybdenum oxide (VI) during co-evaporation was 4: 1 = NPB: molybdenum oxide (VI). The first layer 603 is a layer that functions as a hole generating layer when the light emitting element is operated.

  Next, the second layer 604 was formed on the first layer 603 by evaporating NPB. The thickness of the second layer 604 was set to 20 nm. The second layer 604 functions as a hole transport layer when the light emitting element is operated.

Next, a third layer 605 containing CBP and Ir (Fdppr-Me) ₂ (pic) was formed over the second layer 604 by a co-evaporation method. The thickness of the third layer 605 is set to 30 nm, and the mass ratio of CBP to Ir (Fdppr-Me) ₂ (pic) is 1: 0.05 = CBP: Ir (Fdppr-Me) ₂ (pic) It was made to become. Thus, Ir (Fdppr-Me) ₂ (pic) is in a state of being dispersed in a layer containing CBP as a substrate (matrix). The third layer 605 functions as a light emitting layer when the light emitting element is operated.

  Next, a fourth layer 606 was formed on the third layer 605 by vapor deposition of BCP. The thickness of the fourth layer 606 was set to 20 nm. When the light emitting element is operated, the fourth layer 606 transports electrons to the third layer 605 functioning as a light emitting layer, and holes injected from the first electrode 602 side are transferred to the third layer 605. A function of preventing the layer 605 from penetrating to the other electrode side, and a suppression of movement of excitation energy generated in the third layer 605 from the third layer 605 to another layer It is a layer having the function of The layer having such a function is also called a hole blocking layer or simply a blocking layer.

  Next, a fifth layer 607 containing Alq and lithium (Li) was formed over the fourth layer 606 by a co-evaporation method. The thickness of the fifth layer 607 was 20 nm, and the mass ratio of Alq to lithium (Li) was 1: 0.01 = Alq: lithium (Li). The fifth layer 607 functions as an electron injection layer when the light emitting element is operated.

  Next, a second electrode 608 using aluminum was formed over the fifth layer 607. The thickness of the second electrode 608 was set to 200 nm.

In the light-emitting element manufactured as described above, a current flows when a voltage is applied so that the potential of the first electrode 602 is higher than the potential of the second electrode 608, and the third element functions as a light-emitting layer. In the layer 605, electrons and holes are recombined to generate excitation energy, and light is emitted when the excited Ir (Fdppr-Me) ₂ (pic) returns to the ground state. Note that a layer functioning as a blocking layer may be provided as in this embodiment. As a result, the transfer of excitation energy from the light emitting layer to other layers and the penetration of holes from the light emitting layer to other layers can be suppressed, and a light emitting element that emits light more efficiently can be obtained. .

  After the light-emitting element was sealed in a sealing apparatus in a nitrogen atmosphere so that the light-emitting element was not exposed to the air, the operating characteristics of the light-emitting element were measured. The measurement was performed at room temperature (atmosphere kept at 25 ° C.).

The measurement results are shown in FIGS. FIG. 34 shows the current density-luminance characteristics, FIG. 35 shows the voltage-luminance characteristics, and FIG. 36 shows the brightness-current efficiency characteristics. Note that in FIG. 34, the horizontal axis represents current density (mA / cm ² ) and the vertical axis represents luminance (cd / m ² ). In FIG. 35, the horizontal axis represents voltage (V) and the vertical axis represents luminance (cd / m ² ). In FIG. 36, the horizontal axis represents luminance (cd / m ² ) and the vertical axis represents current efficiency (cd / A). From these results, the light-emitting element manufactured in this example has a current density of 1.80 mA / cm ² when a voltage of 6.6 V is applied, and emits light with a luminance of 1030 cd / m ^2. I understood. Note that the current efficiency when emitting light with a luminance of 1030 cd / m ² was 57.0 cd / A, and it was 16.8% when converted to external quantum efficiency (= number of photons / number of electrons). In addition, the maximum value of external quantum efficiency was 16.9% when light was emitted at a luminance of 604 cd / m ² . In addition, from FIG. 36, in the light emitting element of this example, in the high luminance region of 100 to 1000 cd / m ² , the change in current efficiency with respect to the luminance is very small, and the decrease in current efficiency with the increase in luminance is almost observed. It can be seen that this is a light emitting element that cannot be used. Such a phenomenon is that the light-emitting element of this embodiment does not easily increase non-luminescence transition due to the excitation lifetime of the excited triplet state even in a high luminance region, and can efficiently repeat excitation and emission. It means that it can be done.

  FIG. 37 shows an emission spectrum of the light-emitting element manufactured in this example. In FIG. 37, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit). FIG. 37 indicates that the light-emitting element of this example has a peak of the emission spectrum at 556 nm and exhibits green-yellow light emission. The chromaticity coordinates in the CIE color system were (x, y) = (0.45, 0.55).

In this example, a method for manufacturing a light-emitting element using Ir (Fdppr-iPr) ₂ (pic) synthesized in Synthesis Example 5 as a light-emitting substance and operation characteristics of the light-emitting element will be described. Note that the light-emitting element manufactured in this example has a structure in which five layers are provided between the electrodes in the same manner as the light-emitting element manufactured in Example 4. Therefore, FIG. 27 is also used in the description of this embodiment.

  As shown in FIG. 27, indium tin oxide containing silicon oxide was formed over a glass substrate 601 by a sputtering method, so that a first electrode 602 was formed. The thickness of the first electrode 602 was set to 110 nm. The electrodes were formed to have a square shape with a size of 2 mm × 2 mm.

  Next, the glass substrate 601 over which the first electrode 602 was formed was fixed to a holder provided in a vacuum evaporation apparatus.

Next, after evacuating the vacuum apparatus and reducing the pressure to 1 × 10 ⁻⁴ Pa, NPB and molybdenum oxide (VI) are co-evaporated to oxidize NPB and molybdenum on the first electrode 602. A first layer 603 including a material was formed. The thickness of the first layer 603 was 40 nm, and the mass ratio of NPB and molybdenum oxide (VI) during co-evaporation was 4: 1 = NPB: molybdenum oxide (VI). The first layer 603 is a layer that functions as a hole generating layer when the light emitting element is operated.

  Next, the second layer 604 was formed on the first layer 603 by evaporating NPB. The thickness of the second layer 604 was set to 20 nm. The second layer 604 functions as a hole transport layer when the light emitting element is operated.

Next, a third layer 605 containing CBP and Ir (Fdppr-iPr) ₂ (pic) was formed over the second layer 604 by a co-evaporation method. The thickness of the third layer 605 is set to 30 nm, and the mass ratio of CBP to Ir (Fdppr-iPr) ₂ (pic) is 1: 0.01 = CBP: Ir (Fdppr-iPr) ₂ (pic) It was made to become. As a result, Ir (Fdppr-iPr) ₂ (pic) is in a state of being dispersed in a layer using CBP. The third layer 605 functions as a light emitting layer when the light emitting element is operated.

  Next, a fourth layer 606 was formed on the third layer 605 by evaporating TAZ. The thickness of the fourth layer 606 was set to 20 nm. When the light emitting element is operated, the fourth layer 606 transports electrons to the third layer 605 functioning as a light emitting layer, and holes injected from the first electrode 602 side are transferred to the third layer 605. A function of preventing the layer 605 from penetrating to the other electrode side, and a suppression of movement of excitation energy generated in the third layer 605 from the third layer 605 to another layer It is a layer having the function of The layer having such a function is also called a hole blocking layer or simply a blocking layer.

  Next, a fifth layer 607 containing TAZ and lithium (Li) was formed over the fourth layer 606 by a co-evaporation method. The thickness of the fifth layer 607 was 30 nm, and the mass ratio of TAZ to lithium (Li) was 1: 0.01 = TAZ: lithium (Li). The fifth layer 607 functions as an electron injection layer when the light emitting element is operated.

  Next, a second electrode 608 using aluminum was formed over the fifth layer 607. The thickness of the second electrode 608 was set to 200 nm.

In the light-emitting element manufactured as described above, a current flows when a voltage is applied so that the potential of the first electrode 602 is higher than the potential of the second electrode 608, and the third element functions as a light-emitting layer. In the layer 605, electrons and holes are recombined to generate excitation energy, and light is emitted when the excited Ir (Fdppr-iPr) ₂ (pic) returns to the ground state. Note that a layer functioning as a blocking layer may be provided as in this embodiment. As a result, the transfer of excitation energy from the light emitting layer to other layers and the penetration of holes from the light emitting layer to other layers can be suppressed, and a light emitting element that emits light more efficiently can be obtained. .

  After the light-emitting element was sealed in a sealing apparatus in a nitrogen atmosphere so that the light-emitting element was not exposed to the air, the operating characteristics of the light-emitting element were measured. The measurement was performed at room temperature (atmosphere kept at 25 ° C.).

The measurement results are shown in FIGS. FIG. 38 shows the current density-luminance characteristics, FIG. 39 shows the voltage-luminance characteristics, and FIG. 40 shows the brightness-current efficiency characteristics. In FIG. 38, the horizontal axis represents current density (mA / cm ² ), and the vertical axis represents luminance (cd / m ² ). In FIG. 39, the horizontal axis represents voltage (V) and the vertical axis represents luminance (cd / m ² ). In FIG. 40, the horizontal axis represents luminance (cd / m ² ) and the vertical axis represents current efficiency (cd / A). From these results, the light-emitting element manufactured in this example has a current density of 1.65 mA / cm ² when a voltage of 7.2 V is applied, and emits light with a luminance of 959 cd / m ^2. I understood. Note that the current efficiency when emitting light with a luminance of 959 cd / m ² was 58.1 cd / A, and it was 17.6% when converted to external quantum efficiency (= number of photons / number of electrons). In addition, the maximum value of external quantum efficiency was 18.7% when light was emitted at a luminance of 81.5 cd / m ² .

  A light emission spectrum of the light-emitting element manufactured in this example is shown in FIG. In FIG. 41A, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit). FIG. 41A shows that the light-emitting element of this example has a light emission peak at 545 nm and exhibits green-yellow light emission. The chromaticity coordinates in the CIE color system were (x, y) = (0.43, 0.55).

In this example, the mass ratio of CBP and Ir (Fdppr-iPr) ₂ (pic) in the third layer 605 is different from that of the light-emitting element manufactured in Example 6 (hereinafter referred to as the light-emitting element (6)). Two light-emitting elements (light-emitting element (7-1) and light-emitting element (7-2) were manufactured, and the relationship between the concentration of Ir (Fdppr-iPr) ₂ (pic) contained in the light-emitting layer and the light emission efficiency was examined.

The light-emitting elements (7-1) and (7-2) are different from the light-emitting element manufactured in Example 6 in terms of the mass ratio of CBP to Ir (Fdppr-iPr) ₂ (pic). This is the same as the light-emitting element of Example 6. Therefore, what is necessary is just to quote description of Example 6 about the preparation methods of light emitting element (7-1) and (7-2).

Table 1 shows mass ratios of CBP to Ir (Fdppr-iPr) ₂ (pic) in the light-emitting elements (7-1) and (7-2) and the light-emitting element (6).

  After performing the operation | work which sealed these light emitting elements in the sealing apparatus of nitrogen atmosphere so that a light emitting element might not be exposed to air | atmosphere, the operating characteristic of the light emitting element was measured. The measurement was performed at room temperature (atmosphere kept at 25 ° C.). The measurement results are shown in FIGS. 38 to 40, 41 (B) and 41 (C) together with the data of Example 6. Note that FIG. 41B shows an emission spectrum of the light-emitting element (7-1), and FIG. 41C shows an emission spectrum of the light-emitting element (7-2).

The light-emitting elements (7-1), (7-2), and the light-emitting element (6) emit light, and the light-emitting efficiency of each light-emitting element when the light-emitting element emits light with a luminance of 1000 cd / m ² is examined. The light emission efficiency (vertical axis) is plotted in FIG. 42 against the concentration (horizontal axis) of Ir (Fdppr-iPr) ₂ (pic) included in (that is, included in the light emitting layer).

From FIG. 42, light emission using Ir (Fdppr-iPr) ₂ (pic) as a light-emitting substance even when Ir (Fdppr-iPr) ₂ (pic) is contained at a concentration as high as about 5% by mass. The device emits light with a light emission efficiency of about 50 cd / A, and it has been found that the decrease in light emission efficiency with increasing concentration of Ir (Fdppr-iPr) ₂ (pic) is very small. As a result, among the organometallic complexes of the present invention, such as Ir (Fdppr-iPr) ₂ (pic), an organometallic complex having a feature that an isopropyl group is introduced particularly at the 5-position of the pyrazine skeleton has a concentration of It has been found that quenching (concentration quenching is a phenomenon in which light emission efficiency decreases as the concentration of a light-emitting substance (also referred to as a guest) contained in the light-emitting layer increases).

4A and 4B illustrate one embodiment of a light-emitting device of the present invention. 4A and 4B illustrate a light-emitting device to which the present invention is applied. FIG. 6 illustrates a circuit included in a light-emitting device to which the present invention is applied. The top view of the light-emitting device to which this invention is applied. 4A and 4B illustrate a frame operation of a light-emitting device to which the present invention is applied. Sectional drawing of the light-emitting device to which this invention is applied. 4A and 4B illustrate a light-emitting device to which the present invention is applied. The figure of the electronic device to which this invention is applied. FIG. 3 shows ¹ H-NMR of the organometallic complex of the present invention synthesized in Synthesis Example 1. 4A and 4B show an absorption spectrum and an emission spectrum of the organometallic complex of the present invention synthesized in Synthesis Example 1. FIG. Figure the ^{1 H-NMR} of an organometallic complex of the present invention synthesized in Synthesis Example 2. FIG. 6 shows an absorption spectrum and an emission spectrum of the organometallic complex of the present invention synthesized in Synthesis Example 2. 4A and 4B illustrate a method for manufacturing a light-emitting element including an organometallic complex synthesized in Synthesis Example 1. FIG. 6 shows current density-luminance characteristics of the light-emitting device of Example 2. FIG. 6 is a diagram illustrating voltage-luminance characteristics when the light emitting device of Example 2 is operated. FIG. 6 shows luminance-current efficiency characteristics when the light-emitting device of Example 2 is operated. FIG. 6 shows an emission spectrum obtained when the light emitting device of Example 2 is operated. 9A and 9B illustrate a method for manufacturing a light-emitting element including an organometallic complex synthesized in Synthesis Example 2. FIG. 10 shows current density-luminance characteristics of the light-emitting device of Example 3. FIG. 10 is a graph illustrating voltage-luminance characteristics when the light-emitting device of Example 3 is operated. FIG. 10 shows luminance-current efficiency characteristics when the light-emitting device of Example 3 is operated. FIG. 10 shows an emission spectrum obtained when the light-emitting device of Example 3 is operated. FIG. 6 shows ¹ H-NMR of the organometallic complex of the present invention synthesized in Synthesis Example 3. FIG. 9 shows an absorption spectrum and an emission spectrum of the organometallic complex of the present invention synthesized in Synthesis Example 3. FIG. 6 shows ¹ H-NMR of an organometallic complex synthesized in Synthesis Example 4. FIG. 10 shows an absorption spectrum and an emission spectrum of an organometallic complex synthesized in Synthesis Example 4. 8A and 8B illustrate a method for manufacturing light-emitting elements of Examples 4 to 7. FIG. 10 shows current density-luminance characteristics of the light-emitting device of Example 4. FIG. 10 is a graph illustrating voltage-luminance characteristics when the light-emitting device of Example 4 is operated. FIG. 10 shows luminance-current efficiency characteristics when the light-emitting device of Example 4 is operated. FIG. 10 shows an emission spectrum obtained when the light-emitting device of Example 4 is operated. FIG. 10 shows ¹ H-NMR of the organometallic complex synthesized in Synthesis Example 5. FIG. 10 shows an absorption spectrum and an emission spectrum of an organometallic complex synthesized in Synthesis Example 5. FIG. 10 shows current density-luminance characteristics of the light-emitting device of Example 5. FIG. 10 shows voltage-luminance characteristics when the light-emitting device of Example 5 is operated. FIG. 6 shows luminance-current efficiency characteristics when the light-emitting device of Example 5 is operated. FIG. 10 shows an emission spectrum obtained when the light-emitting device of Example 5 was operated. FIG. 10 is a graph showing current density-luminance characteristics of light-emitting devices of Examples 6 and 7. FIG. 10 is a graph illustrating voltage-luminance characteristics when the light-emitting devices of Examples 6 and 7 are operated. FIG. 10 shows luminance-current efficiency characteristics when the light-emitting devices of Examples 6 and 7 are operated. The figure showing the emission spectrum obtained when the light-emitting device of Example 6, 7 was operated. The figure showing the relationship between the density | concentration of Ir (Fdppr-iPr) ₂ (pic), and luminous efficiency. FIG. 10 shows ¹ H-NMR of the organometallic complex synthesized in Synthesis Example 6. FIG. 9 shows an absorption spectrum and an emission spectrum of an organometallic complex synthesized in Synthesis Example 6.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Substrate 11 Transistor 12 Light emitting element 13 1st electrode 14 2nd electrode 15 Layer 16 Interlayer insulation film 17 Wiring 18 Partition layer 19 Interlayer insulation film 151 1st electrode 152 2nd electrode 161 Hole injection layer 162 Hole Transport layer 163 Light emitting layer 164 Electron transport layer 165 Electron injection layer 301 Glass substrate 302 1st electrode 303 1st layer 304 2nd layer 305 3rd layer 306 4th layer 307 5th layer 308 6th Layer 309 second electrode 401 glass substrate 402 first electrode 403 first layer 404 second layer 405 third layer 406 fourth layer 407 fifth layer 408 sixth layer 409 second electrode 501 Subframe 502 Subframe 503 Subframe 504 Subframe 601 Glass substrate 602 First electrode 603 First layer 604 Second layer 605 Third layer 6 6 4th layer 607 5th layer 608 2nd electrode 901 Transistor 902 Transistor 903 Light emitting element 911 Gate signal line 912 Source signal line 913 Write gate signal line drive circuit 914 Erase gate signal line drive circuit 915 Source signal Line driver circuit 916 Power source 917 Current supply line 918 Switch 919 Switch 920 Switch 1001 Transistor 1002 Transistor 1003 Gate signal line 1004 Source signal line 1005 Current supply line 1006 Electrode 1901 Substrate 1902 Electrode 1904 Partition layer 1905 Light emitting layer 1906 Electrode 1907 Substrate 501a Writing period 501b Holding period 502a Writing period 502b Holding period 503a Writing period 503b Holding period 504a Writing period 504b Holding period 504c Erase period 504d Light period 5521 body 5522 housing 5523 display unit 5524 keyboard 5531 display unit 5532 housing 5533 speaker 5551 display unit 5552 body 5553 antenna 5554 voice output portion 5555 a voice input unit 5556 operation switches 6500 substrate 6503 FPC
6504 Printed Wiring Board (PWB)
6511 Pixel portion 6512 Source signal line drive circuit 6513 Write gate signal line drive circuit 6514 Erase gate signal line drive circuit

Claims (35)

An organometallic complex including a structure represented by the general formula (1).

(In the formula, each of R ¹ and R ² represents any of a halogen group, —CF ₃ group, cyano group, and alkoxycarbonyl group. Also, R ³ and R ⁴ are each hydrogen or C 1 -C 1. 4 represents an alkyl group of 4. M represents a Group 9 element or a Group 10 element.) The organometallic complex according to claim ¹ , wherein each of R ¹ and R ² is a fluoro group or a —CF ₃ group. The organometallic complex according to claim 1 or 2, wherein each of R ³ and R ⁴ is a methyl group or an isopropyl group. An organometallic complex represented by the general formula (2).

(In the formula, each of R ⁵ and R ⁶ represents any of a halogen group, —CF ₃ group, cyano group, and alkoxycarbonyl group. Also, R ⁷ and R ⁸ are each hydrogen or C 1 -C 1. And M represents a Group 9 element or a Group 10 element, n represents n = 2 when M is a Group 9 element, and M represents a Group 10 element. In this case, n = 1, and L represents a monoanionic ligand.) The organometallic complex according to claim 4, wherein the monoanionic ligand is a ligand represented by any one of structural formulas (1) to (7).

6. The organometallic complex according to claim 4, wherein each of R ⁵ and R ⁶ is a fluoro group or a —CF ₃ group. The organometallic complex according to any one of claims 4 to 6, wherein R ⁷ and R ⁸ are each a methyl group or an isopropyl group. An organometallic complex including a structure represented by the general formula (3).

(In the formula, R ⁹ and R ¹⁰ each represent any of a halogen group, —CF ₃ group, cyano group, and alkoxycarbonyl group. Also, R ¹¹ and R ¹² are each hydrogen or C 1 -C 1. Any one of the 4 alkyl groups.) The organometallic complex according to claim 8, wherein each of R ⁹ and R ¹⁰ is a fluoro group or a -CF ₃ group. The organometallic complex according to claim 8 or 9, wherein each of R ¹¹ and R ¹² is a methyl group or an isopropyl group. An organometallic complex represented by the general formula (4).

(In the formula, each of R ¹³ and R ¹⁴ represents any of a halogen group, —CF ₃ group, cyano group, and alkoxycarbonyl group. Also, R ¹⁵ and R ¹⁶ are each hydrogen or C 1 -C 1. 4 represents an alkyl group of 4. In addition, L represents a monoanionic ligand.) The organometallic complex according to claim 11, wherein the monoanionic ligand is a ligand represented by any one of structural formulas (1) to (7).

The organometallic complex according to claim 11 or 12, wherein each of R ¹³ and R ¹⁴ is a fluoro group or a -CF ₃ group. 14. The organometallic complex according to claim 11, wherein each of R ¹⁵ and R ¹⁶ is a methyl group or an isopropyl group. An organometallic complex including a structure represented by the general formula (5).

(In the formula, each of R ¹⁷ and R ¹⁸ represents any of a halogen group, —CF ₃ group, cyano group, and alkoxycarbonyl group. Also, R ¹⁹ represents hydrogen or an alkyl group having 1 to 4 carbon atoms. Represents either one.) 16. The organometallic complex according to claim 15, wherein each of R ¹⁷ and R ¹⁸ is a fluoro group or a —CF ₃ group. The organometallic complex according to claim 15 or 16, wherein R ¹⁹ is a methyl group or an isopropyl group. An organometallic complex represented by the general formula (6).

(In the formula, each of R ²⁰ and R ²¹ represents any of a halogen group, —CF ₃ group, cyano group, and alkoxycarbonyl group. Also, R ²² represents hydrogen or an alkyl group having 1 to 4 carbon atoms. And L represents a monoanionic ligand.) The organometallic complex according to claim 18, wherein the monoanionic ligand is a ligand represented by any one of structural formulas (1) to (7).

The organometallic complex according to claim 18, wherein each of R ²⁰ and R ²¹ is a fluoro group or a —CF ₃ group. 20. The organometallic complex according to claim 18, wherein R ²² is a methyl group or an isopropyl group, respectively. An organometallic complex including a structure represented by the general formula (13).

(Wherein R ^{57 to} R ⁶² each represent a halogen group or —CF ₃ group. R ⁶³ and R ⁶⁴ each represent either hydrogen or an alkyl group having 1 to 4 carbon atoms. M represents a Group 9 element or a Group 10 element.) An organometallic complex represented by the general formula (14).

(In the formula, R ^{65 to} R ⁷⁰ each represent a halogen group or —CF ₃ group. R ⁷¹ and R ⁷² each represent hydrogen or an alkyl group having 1 to 4 carbon atoms. M represents a Group 9 element or Group 10. n represents n = 2 when M is a Group 9 element and n = 1 when M is a Group 10 element. , L represents a monoanionic ligand.) The organometallic complex according to claim 23, wherein the monoanionic ligand is a ligand represented by any one of structural formulas (1) to (7).

An organometallic complex including a structure represented by the general formula (15).

(In the formula, R ^{73 to} R ⁷⁸ each represent a halogen group or —CF ₃ group. R ⁷⁹ and R ⁸⁰ each represent either hydrogen or an alkyl group having 1 to 4 carbon atoms. ) An organometallic complex represented by the general formula (16).

(In the formula, R ^{81 to} R ⁸⁶ each represent a halogen group or —CF ₃ group. Also, R ⁸⁷ and R ⁸⁸ each represent either hydrogen or an alkyl group having 1 to 4 carbon atoms. L represents a monoanionic ligand.) 27. The organometallic complex according to claim 26, wherein the monoanionic ligand is a ligand represented by any one of structural formulas (1) to (7).

An organometallic complex including a structure represented by the general formula (17).

(Wherein R ^{89 to} R ⁹⁴ each represent a halogen group or a —CF ₃ group. R ⁹⁵ represents either hydrogen or an alkyl group having 1 to 4 carbon atoms.) An organometallic complex represented by the general formula (18).

(Wherein R ^{96 to} R ¹⁰¹ each represents a halogen group or a —CF ₃ group. R ¹⁰² represents either hydrogen or an alkyl group having 1 to 4 carbon atoms. L represents a mono group. Represents an anionic ligand.) 30. The organometallic complex according to claim 29, wherein the monoanionic ligand is a ligand represented by any one of structural formulas (1) to (7).

An organometallic complex represented by the general formula (19).

(In the formula, R ¹⁰³ represents hydrogen, a methyl group, or an isopropyl group. L represents a monoanionic ligand.) 32. The organometallic complex according to claim 31, wherein the monoanionic ligand is a ligand represented by any one of structural formulas (8) to (10).

  33. A light-emitting element having a layer containing the organometallic complex according to any one of claims 1 to 32 between electrodes.   A light emitting device comprising the light emitting element according to claim 33. An electronic apparatus comprising the light emitting device according to claim 34.

Images