JP7287953B2 - Organometallic complex, light-emitting device, light-emitting device, electronic device, and lighting device - Google Patents

Description

One embodiment of the present invention relates to organic compounds, light-emitting devices, light-emitting devices, electronic devices, and lighting devices. However, one embodiment of the present invention is not limited thereto. That is, one aspect of the present invention relates to an article, method, manufacturing method, or driving method. Alternatively, one aspect of the invention relates to a process, machine, manufacture, or composition of matter. Further, specifically, a semiconductor device, a display device, a liquid crystal display device, and the like can be given as examples.

A light-emitting device (also referred to as a light-emitting element or an organic EL element) in which an EL layer is sandwiched between a pair of electrodes has characteristics such as thinness and light weight, high-speed response to input signals, and low power consumption. The applied display is attracting attention as a next-generation flat panel display.

In a light-emitting device, when a voltage is applied between a pair of electrodes, electrons and holes injected from each electrode are recombined in the EL layer, and the light-emitting substance (organic compound) contained in the EL layer is excited. Light is emitted when the excited state returns to the ground state. As types of excited states, there are a singlet excited state (S ^* ) and a triplet excited state (T ^* ). Light emission from the singlet excited state is fluorescence, and light emission from the triplet excited state is phosphorescence. being called. It is also believed that their statistical production ratio in light emitting devices is S ^* :T ^* =1:3.

Among the above-mentioned light-emitting substances, compounds that can convert the energy in the singlet excited state into luminescence are called fluorescent compounds (fluorescent materials), and can convert the energy in the triplet excited state into luminescence. Such compounds are called phosphorescent compounds (phosphorescent materials).

Therefore, based on the above generation ratio, the theoretical limit of the internal quantum efficiency (ratio of photons generated to injected carriers) in a light emitting device using each of the above light emitting materials is is 25%, and when a phosphorescent material is used, it is 75%.

That is, a light-emitting device using a phosphorescent material can achieve higher efficiency than a light-emitting device using a fluorescent material. Therefore, in recent years, various types of phosphorescent materials have been actively developed. In particular, due to its high phosphorescence quantum yield, organometallic complexes having iridium or the like as a central metal are attracting attention (for example, Patent Document 1).

JP-A-2009-23938

As reported in the above-mentioned Patent Document 1, the development of phosphorescent materials exhibiting excellent properties is progressing, but the development of new materials exhibiting even better properties is desired.

Accordingly, one embodiment of the present invention provides a novel organic compound (including an organometallic complex). Further, one embodiment of the present invention provides a novel organometallic complex having a stable molecular structure. Another embodiment of the present invention provides an organometallic complex having an emission peak in a long wavelength region (visible region or near-infrared region with a wavelength of 700 nm or longer). Further, one embodiment of the present invention provides a novel organometallic complex that can be used for a light-emitting device. Further, one embodiment of the present invention provides a novel organometallic complex that can be used for an EL layer of a light-emitting device. Further, one embodiment of the present invention provides a highly reliable novel light-emitting device using a novel organometallic complex. Another embodiment of the present invention provides a novel light-emitting device, a novel electronic device, or a novel lighting device. The description of these problems does not preclude the existence of other problems. Moreover, one aspect of the present invention does not necessarily have to solve all of these problems. In addition, problems other than these are self-evident from the descriptions of the specification, drawings, claims, etc., and it is possible to extract problems other than these from the descriptions of the specification, drawings, claims, etc. is.

In one aspect of the present invention, the central metal is coordinated with a ligand having a benzonaphthoquinoxaline (bnq) skeleton, and this ligand is the central metal (group 9 or 10: It is an organometallic complex represented by the following general formula (G1), in which a hydrogen bond is formed between nitrogen that does not bond to Ir, Pt) and hydrogen of the condensed ring of the bnq skeleton.

However, in the general formula (G1), M represents a Group 9 element or a Group 10 element, R ¹ to R ¹⁰ each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted carbon It represents either an aryl group of 6 to 12 carbon atoms or a substituted or unsubstituted heteroaryl group of 3 to 12 carbon atoms. In addition, R ⁹ and R ¹⁰ may combine with each other to form a substituted or unsubstituted saturated or unsaturated ring having 3 to 24 carbon atoms. Moreover, L represents a monoanionic ligand. When M is a Group 9 element, m+n=3 (where m=0, 1 or 2, n=1, 2, or 3), and when M is a Group 10 element , m+n=2, where m=0 or 1 and n=1 or 2.

Another embodiment of the present invention is an organometallic complex represented by General Formula (G2) below.

However, in general formula (G2), R ¹ to R ¹⁰ are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, or a substituted or unsubstituted represents any heteroaryl group having 3 to 12 carbon atoms. In addition, R ⁹ and R ¹⁰ may combine with each other to form a substituted or unsubstituted saturated or unsaturated ring having 3 to 24 carbon atoms. Moreover, L represents a monoanionic ligand.

In each of the above structures, the monoanionic ligand includes a monoanionic bidentate chelate ligand having a β-diketone structure, a monoanionic bidentate chelate ligand having a carboxyl group, a phenolic Monoanionic bidentate chelate ligands with a hydroxyl group, monoanionic bidentate chelate ligands in which both coordinating elements are nitrogen, or form metal-carbon bonds with iridium by cyclometallation any one of the bidentate ligands.

Further, in each of the above structures, the monoanionic ligand is any one of the following general formulas (L1) to (L7).

However, in the general formulas (L1) to (L7), R ⁵¹ to R ⁸⁹ are each independently hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a halogeno group, a vinyl group, a substituted or unsubstituted haloalkyl group having 1 to 6 carbon atoms, substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, substituted or unsubstituted alkylthio group having 1 to 6 carbon atoms, substituted or unsubstituted aryl having 6 to 13 carbon atoms represents a group. In addition, A ¹ to A ¹³ each independently represent an sp ^2- hybridized carbon bonding to nitrogen or hydrogen, or an sp ^2- hybridized carbon having a substituent, and the substituent is an alkyl group having 1 to 6 carbon atoms, halogeno group, a haloalkyl group having 1 to 6 carbon atoms, or a phenyl group.

Another embodiment of the present invention is an organometallic complex represented by General Formula (G3) below.

However, in general formula (G3), R ¹ to R ¹³ are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, or a substituted or unsubstituted represents any heteroaryl group having 3 to 12 carbon atoms. In addition, R ⁹ and R ¹⁰ may combine with each other to form a substituted or unsubstituted saturated or unsaturated ring having 3 to 24 carbon atoms.

Another embodiment of the present invention is an organometallic complex represented by Structural Formula (100) or Structural Formula (118).

Another aspect of the present invention is condensation of the nitrogen that does not bond to the central metal (Group 9 or Group 10: Ir, Pt) among the nitrogens of the benzonaphthoquinoxaline (bnq) skeleton that coordinates to the central metal, and the bnq skeleton. It is a light-emitting device using an organometallic complex that forms a hydrogen bond with a ring hydrogen. Note that a light-emitting device including another organic compound in addition to the above organometallic complex is also included in one embodiment of the present invention.

Another embodiment of the present invention is a light-emitting device using the above-described organometallic complex of one embodiment of the present invention. Note that a light-emitting device formed using the organometallic complex of one embodiment of the present invention in an EL layer provided between a pair of electrodes and a light-emitting layer included in the EL layer is also included in one embodiment of the present invention. . In addition to light-emitting devices, light-emitting devices having transistors, substrates, and the like are also included in the scope of the invention. Furthermore, in addition to these light emitting devices, the scope of the invention also includes electronic devices and lighting devices having microphones, cameras, operation buttons, external connectors, housings, covers, support bases, speakers, and the like.

The organometallic complex that is one embodiment of the present invention can be used for a light-emitting layer of a light-emitting device in combination with another organic compound. That is, since it is possible to obtain light emission from the triplet excited state from the light-emitting layer, it is possible to improve the efficiency of the light-emitting device, which is very effective. Therefore, a light-emitting device in which an organometallic complex of one embodiment of the present invention is used in combination with another organic compound for a light-emitting layer is included in one embodiment of the present invention. Furthermore, in addition to the above, a structure in which a third substance is added to the light-emitting layer may be employed.

One embodiment of the present invention includes a light-emitting device including a light-emitting device, and further includes a lighting device including a light-emitting device. Therefore, a light-emitting device in this specification refers to an image display device or a light source (including a lighting device). Further, a module in which a connector such as FPC (Flexible printed circuit) or TCP (Tape Carrier Package) is attached to the light emitting device, a module in which a printed wiring board is provided at the end of TCP, or a COG (Chip On Glass) is attached to the light emitting device. All modules in which an IC (integrated circuit) is directly mounted are included in the light emitting device.

One embodiment of the present invention can provide novel organic compounds (including organometallic complexes). Also, a novel organometallic complex having a stable molecular structure can be provided. Further, one embodiment of the present invention can provide an organometallic complex having an emission peak in a long wavelength region (visible region or near-infrared region with a wavelength of 700 nm or longer). Further, one embodiment of the present invention can provide a novel organometallic complex that can be used for a light-emitting device. Further, one embodiment of the present invention can provide a novel organometallic complex that can be used for an EL layer of a light-emitting device. Further, a highly reliable novel light-emitting device using the novel organometallic complex which is one embodiment of the present invention can be provided. Further, a novel light-emitting device, a novel electronic device, or a novel lighting device can be provided. Note that the description of these effects does not preclude the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. Effects other than these are self-evident from the descriptions of the specification, drawings, claims, etc., and it is possible to extract effects other than these from the descriptions of the specification, drawings, claims, etc. is.

(A) and (C) each illustrate a structure of a light-emitting device. (B) and (D) are diagrams for explaining a light-emitting device having a stacked structure (tandem structure). 4A and 4B illustrate a light-emitting device; 4A and 4B illustrate a light-emitting device; 4A and 4B illustrate electronic devices; 4A and 4B illustrate electronic devices; A figure explaining a car. 4A and 4B illustrate a lighting device; ¹ H-NMR chart of the organometallic complex represented by Structural Formula (100). UV-visible absorption spectrum and emission spectrum in a solution of the organometallic complex represented by Structural Formula (100). 4A and 4B illustrate a light-emitting device; FIG. 3 shows current density-luminance characteristics of light-emitting device 1 and comparative light-emitting device 2; FIG. 3 is a diagram showing voltage-luminance characteristics of light-emitting device 1 and comparative light-emitting device 2; FIG. 4 is a diagram showing luminance-current efficiency characteristics of light-emitting device 1 and comparative light-emitting device 2; FIG. 3 shows voltage-current characteristics of light-emitting device 1 and comparative light-emitting device 2; FIG. 3 shows emission spectra of light-emitting device 1 and comparative light-emitting device 2; FIG. 2 shows the reliability of light-emitting device 1 and comparative light-emitting device 2; ¹ H-NMR chart of the organometallic complex represented by Structural Formula (118). UV-visible absorption spectrum and emission spectrum in a solution of the organometallic complex represented by Structural Formula (118). FIG. 3 is a diagram showing the current density-radiant emittance characteristics of the light emitting device 3; FIG. 3 is a diagram showing voltage-current density characteristics of the light-emitting device 3; 4 is a diagram showing current density-radiant flux characteristics of the light-emitting device 3. FIG. FIG. 3 shows the voltage-radiant emittance characteristics of the light-emitting device 3; FIG. 3 is a diagram showing current density-external quantum efficiency characteristics of the light-emitting device 3; FIG. 3 shows an emission spectrum of the light emitting device 3; FIG. 3 is a diagram showing the reliability of the light emitting device 3;

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and various changes in form and detail can be made without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the descriptions of the embodiments shown below.

Note that the position, size, range, etc. of each configuration shown in the drawings, etc. may not represent the actual position, size, range, etc. for ease of understanding. Therefore, the disclosed invention is not necessarily limited to the position, size, range, etc. disclosed in the drawings and the like.

Further, in this specification and the like, when describing the configuration of the invention using the drawings, the same reference numerals are commonly used between different drawings.

(Embodiment 1)
In this embodiment, an organometallic complex that is one embodiment of the present invention will be described.

In the organometallic complex that is one embodiment of the present invention, the central metal is coordinated with a ligand having a benzonaphthoquinoxaline (bnq) skeleton, and the ligand is the central metal (9 Group or Group 10: It has a structure represented by the following general formula (G1) in which a hydrogen bond is formed between a nitrogen not bonded to Ir, Pt) and a hydrogen of a condensed ring of the bnq skeleton.

In general formula (G1), M represents a Group 9 element or a Group 10 element, and R ¹ to R ¹⁰ each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted 6 carbon atoms. It represents either an aryl group of up to 12 or a substituted or unsubstituted heteroaryl group of 3 to 12 carbon atoms. In addition, R ⁹ and R ¹⁰ may combine with each other to form a substituted or unsubstituted C 3-24, preferably substituted or unsubstituted C 3-12 saturated or unsaturated ring. Moreover, L represents a monoanionic ligand. When M is a Group 9 element, m+n=3 (where m=0, 1 or 2, n=1, 2, or 3), and when M is a Group 10 element , m+n=2, where m=0 or 1 and n=1 or 2.

An organometallic complex that is another embodiment of the present invention is an organometallic complex represented by General Formula (G2) below.

In general formula (G2), each of R ¹ to R ¹⁰ is independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms. represents any of 3 to 12 heteroaryl groups. In addition, R ⁹ and R ¹⁰ may combine with each other to form a substituted or unsubstituted C 3-24, preferably substituted or unsubstituted C 3-12 saturated or unsaturated ring. Moreover, L represents a monoanionic ligand.

The monoanionic ligands in the general formulas (G1) and (G2) are monoanionic bidentate chelate ligands having a β-diketone structure, monoanionic bidentate chelate ligands having a carboxyl group. Chelating ligands, monoanionic bidentate chelating ligands with phenolic hydroxyl groups, monoanionic bidentate chelating ligands with two coordinating elements both nitrogen, or iridium and iridium by cyclometallation Any one of the bidentate ligands that form a metal-carbon bond.

Note that the monoanionic ligands in the general formulas (G1) and (G2) are specifically any one of the following general formulas (L1) to (L7).

In general formulas (L1) to (L7), R ⁵¹ to R ⁸⁹ are each independently hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a halogeno group, a vinyl group, a substituted or unsubstituted A haloalkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, or a substituted or unsubstituted alkylthio group having 1 to 6 carbon atoms, a substituted or unsubstituted 6 to 13 carbon atoms represents an aryl group. In addition, A ¹ to A ¹³ each independently represent an sp ^2- hybridized carbon bonding to nitrogen or hydrogen, or an sp ^2- hybridized carbon having a substituent, and the substituent is an alkyl group having 1 to 6 carbon atoms, halogeno group, a haloalkyl group having 1 to 6 carbon atoms, or a phenyl group.

An organometallic complex that is another embodiment of the present invention is an organometallic complex represented by General Formula (G3) below.

In general formula (G3), each of R ¹ to R ¹³ is independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms. represents any of 3 to 12 heteroaryl groups. In addition, R ⁹ and R ¹⁰ may combine with each other to form a substituted or unsubstituted C 3-24, preferably substituted or unsubstituted C 3-12 saturated or unsaturated ring.

In addition, in the organometallic complexes represented by the general formula (G1), the general formula (G2), and the general formula (G3), the substitution preferably means a methyl group, an ethyl group, an n-propyl group, Alkyl groups having 1 to 6 carbon atoms such as isopropyl group, sec-butyl group, tert-butyl group, n-pentyl group and n-hexyl group, phenyl group, o-tolyl group, m-tolyl group, p- It represents substitution with a substituent such as an aryl group having 6 to 12 carbon atoms such as a tolyl group, 1-naphthyl group, 2-naphthyl group, 2-biphenyl group, 3-biphenyl group and 4-biphenyl group. Moreover, these substituents may be bonded to each other to form a ring. For example, when the aryl group is a 2-fluorenyl group having two phenyl groups at the 9-position as substituents, the phenyl groups are bonded to each other to form a spiro-9,9'-bifluoren-2-yl group. can be More specific examples include phenyl group, tolyl group, xylyl group, biphenyl group, indenyl group, naphthyl group, fluorenyl group and the like.

In addition, in the organometallic complexes represented by the general formula (G1), the general formula (G2), and the general formula (G3), an alkyl group having 1 to 6 carbon atoms in R ¹ to R ¹³ in the formulas Specific examples of are methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, sec-pentyl group, tert-pentyl group, neopentyl group, hexyl group, isohexyl group, sec-hexyl group, tert-hexyl group, neohexyl group, 3-methylpentyl group, 2-methylpentyl group, 2-ethylbutyl group, 1,2-dimethylbutyl group, 2,3 -dimethylbutyl group and the like.

Further, in the organometallic complexes represented by the general formula (G1), the general formula (G2), and the general formula (G3), the number of carbon atoms forming the ring in R ¹ to R ¹³ in the formulas is 6. Specific examples of substituted or unsubstituted aryl groups of 1 to 12 include a phenyl group, a biphenyl group, a naphthyl group, an indenyl group and the like, preferably a phenyl group.

Further, in the organometallic complexes represented by the general formula (G1), the general formula (G2), and the general formula (G3), the number of carbon atoms forming the ring in R ¹ to R ¹³ in the formulas is 3. Specific examples of substituted or unsubstituted heteroaryl groups of to 12 include a triazinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridyl group, a quinolyl group, an isoquinolyl group, a benzothienyl group, a benzofuranyl group, an indolyl group, a dibenzothienyl group and a dibenzo A furanyl group, a carbazolyl group, and the like can be mentioned.

Next, specific structural formulas of the above-described organometallic complexes of one embodiment of the present invention are shown below.

Note that the organometallic complexes represented by the structural formulas (100) to (125) are represented by any one of the general formula (G1), the general formula (G2), and the general formula (G3). This is an example of an organometallic complex that is one embodiment of the present invention. However, the organometallic complex that is one embodiment of the present invention is not limited thereto.

Next, an example of a method for synthesizing an organometallic complex that is one embodiment of the present invention represented by General Formula (G1) below is described.

However, in the general formula (G1), M represents a Group 9 element or a Group 10 element, R ¹ to R ¹⁰ each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted carbon It represents either an aryl group of 6 to 12 carbon atoms or a substituted or unsubstituted heteroaryl group of 3 to 12 carbon atoms. In addition, R ⁹ and R ¹⁰ may combine with each other to form a substituted or unsubstituted saturated or unsaturated ring having 3 to 24 carbon atoms. Moreover, L represents a monoanionic ligand. When M is a Group 9 element, m+n=3 (where m=0, 1 or 2, n=1, 2, or 3), and when M is a Group 10 element , m+n=2, where m=0 or 1 and n=1 or 2.

<<Method for synthesizing benzo[f]naphtho[2,1-h]quinoxaline derivative represented by general formula (G0)>>
First, an example of a method for synthesizing a benzo[f]naphtho[2,1-h]quinoxaline derivative represented by the following general formula (G0) is described.

In general formula (G0), each of R ¹ to R ¹⁰ is independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms. represents any of 3 to 12 heteroaryl groups. In addition, R ⁹ and R ¹⁰ may combine with each other to form a substituted or unsubstituted saturated or unsaturated ring having 3 to 24 carbon atoms.

Note that the benzo[f]naphtho[2,1-h]quinoxaline derivative represented by the general formula (G0) can be prepared by a diketone compound (A1) and a diamine compound ( It can be obtained by reacting with A2).

Alternatively, the diketone compound (B1) and the diamine compound (B2) may be reacted as shown in the synthesis scheme (A-1') below.

In the synthesis schemes (A-1) and (A-1′) above, each of R ¹ to R ¹⁰ is independently hydrogen, an alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted or a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms. In addition, R ⁹ and R ¹⁰ may combine with each other to form a substituted or unsubstituted saturated or unsaturated ring having 3 to 24 carbon atoms.

<<Method for Synthesizing Organometallic Complex Represented by General Formula (G1)>>
Next, a method for synthesizing the organometallic complex represented by General Formula (G1) is described.

First, as shown in the following synthesis scheme (A-2), a benzo[f]naphtho[2,1-h]quinoxaline derivative or a monoanionic ligand L represented by the general formula (G0) and a halogen are and a group 9 or group 10 metal compound containing no solvent, or an alcoholic solvent (glycerol, ethylene glycol, 2-methoxyethanol, 2-ethoxyethanol, etc.) alone, or one or more alcoholic solvents and water by heating in an inert gas atmosphere using a mixed solvent of (C1), which is a type of organometallic complex having a halogen-bridged structure, or a binuclear complex containing a monoanionic ligand. (C2) can be obtained. A heating means is not particularly limited, and an oil bath, a sand bath, an aluminum block, or the like can be used. It is also possible to use microwaves as heating means.

Furthermore, as shown in Synthesis Scheme (A-3), the dinuclear complex (C1) or (C2) obtained in Synthesis Scheme (A-2) above and the benzo[f]naphtho[ By reacting a 2,1-h]quinoxaline derivative or a monoanionic ligand L under an inert gas atmosphere, an organometallic complex represented by general formula (G1) can be obtained.

In the above synthesis scheme (A-2) and the above synthesis scheme (A-3), M represents a Group 9 element or a Group 10 element, and R ¹ to R ¹⁰ are each independently hydrogen and 1 carbon atom. It represents either an alkyl group of up to 6, a substituted or unsubstituted aryl group of 6 to 12 carbon atoms, or a substituted or unsubstituted heteroaryl group of 3 to 12 carbon atoms. In addition, R ⁹ and R ¹⁰ may combine with each other to form a substituted or unsubstituted saturated or unsaturated ring having 3 to 24 carbon atoms. Moreover, L represents a monoanionic ligand. When M is a Group 9 element, m+n=3 (where m=0, 1 or 2, n=1, 2, or 3), and when M is a Group 10 element , m+n=2, where m=0 or 1 and n=1 or 2.

Further, the organometallic complex represented by the general formula (G1) is a group 9 or 10 metal compound containing a halogen and the above general formula (G0), as shown in the synthesis scheme (A-3′) below. After heating a benzo[f]naphtho[2,1-h]quinoxaline derivative or a monoanionic ligand L represented by in an inert gas atmosphere, the monoanionic ligand L or the above general formula It can also be obtained by adding a benzo[f]naphtho[2,1-h]quinoxaline derivative represented by (G0) and heating.

In the above synthesis scheme (A-3′), M represents a group 9 element or a group 10 element, R ¹ to R ¹⁰ are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, substituted or unsubstituted represents either an aryl group having 6 to 12 carbon atoms or a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms. In addition, R ⁹ and R ¹⁰ may combine with each other to form a substituted or unsubstituted saturated or unsaturated ring having 3 to 24 carbon atoms. Moreover, L represents a monoanionic ligand. When M is a Group 9 element, m+n=3 (where m=0, 1 or 2, n=1, 2, or 3), and when M is a Group 10 element , m+n=2, where m=0 or 1 and n=1 or 2.

<<Method for Synthesizing Organometallic Complex Represented by General Formula (G1′)>>
Next, in the organometallic complex represented by the general formula (G1), M is a Group 9 element and n = 3 or M is a Group 10 element and n = 2, and the following general formula (G1′) An example of a method for synthesizing the represented organometallic complex will be described. In general formula (G1′), M represents a Group 9 element or Group 10 element, and R ¹ to R ¹⁰ each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted It represents either an aryl group having 6 to 12 carbon atoms or a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms. In addition, R ⁹ and R ¹⁰ may combine with each other to form a substituted or unsubstituted saturated or unsaturated ring having 3 to 24 carbon atoms. Moreover, L represents a monoanionic ligand.

As shown in the following scheme (A-3''), a benzo[f]naphtho[2,1-h]quinoxaline derivative represented by the general formula (G0) and a Group 9 or Group 10 compound containing a halogen After mixing with a metal compound or an organic compound of group 9 or 10, the mixture is heated in an inert gas atmosphere to obtain an organometallic complex having a structure represented by general formula (G1′). be able to.

In the above synthesis scheme (A-3''), M represents a Group 9 element or a Group 10 element, R ¹ to R ¹⁰ are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted It represents either a substituted C6-C12 aryl group or a substituted or unsubstituted C3-C12 heteroaryl group. In addition, R ⁹ and R ¹⁰ may combine with each other to form a substituted or unsubstituted saturated or unsaturated ring having 3 to 24 carbon atoms. Moreover, L represents a monoanionic ligand.

An example of a method for synthesizing an organometallic complex that is one embodiment of the present invention has been described above; however, the present invention is not limited to this, and any other synthesis method may be used.

As described above, the methods for synthesizing the organometallic complexes represented by the general formulas (G1) and (G1′) are described as organometallic complexes of one embodiment of the present invention, but the present invention is limited thereto. may be synthesized by other synthetic methods.

In the organometallic complex that is one embodiment of the present invention, the central metal is coordinated with a ligand having a benzonaphthoquinoxaline (bnq) skeleton, and the ligand is the central metal among the nitrogen atoms in the bnq skeleton. A hydrogen bond is formed between the nitrogen not bonded to (group 9 or group 10: Ir, Pt) and the hydrogen of the condensed ring of the bnq skeleton. With such a structure, conjugation is wider than in the case of the dibenzoquinoxaline (dbq) skeleton, in which a hydrogen bond is less likely to be formed with the hydrogen of the condensed ring. It is possible to shift the maximum emission wavelength in the longer wavelength direction. Furthermore, by condensing a naphthyl group to the pyrazine ring of the bnq skeleton, the π-conjugated system can be extended and the LUMO level can be stabilized, making it possible to shift the maximum emission wavelength to a longer wavelength direction. . Therefore, it is possible to provide an organometallic complex having an emission peak in the long wavelength region (visible region or near-infrared region with a wavelength of 700 nm or longer). Further, the formation of the above hydrogen bond can stabilize the structure of the organometallic complex. Therefore, it is possible to improve the reliability of a light-emitting device using this organometallic complex.

Further, with the use of the organometallic complex which is one embodiment of the present invention, a highly reliable light-emitting device, light-emitting device, electronic device, or lighting device can be realized.

Note that although the organometallic complex that is one embodiment of the present invention is described in this embodiment, one embodiment of the present invention is not limited thereto. That is, it is possible to combine various aspects of the invention shown in other embodiments.

(Embodiment 2)
In this embodiment, a light-emitting device that is one embodiment of the present invention will be described. Note that the organometallic complex that is one embodiment of the present invention can be used for the light-emitting device described in this embodiment.

<<Basic Structure of Light-Emitting Device>>
FIG. 1A shows a light-emitting device in which an EL layer is sandwiched between a pair of electrodes. Specifically, it has a structure in which an EL layer 103 including a light-emitting layer is sandwiched between a first electrode 101 and a second electrode 102 .

In FIG. 1B, a plurality of (two layers in FIG. 1B) EL layers (103a and 103b) are provided between a pair of electrodes, and a charge generation layer 104 is sandwiched between the EL layers. A light-emitting device with a laminated structure (tandem structure) is shown. Such a tandem-structured light-emitting device can realize a light-emitting device that can be driven at a low voltage and has low power consumption.

Note that when a voltage is applied to the first electrode 101 and the second electrode 102, the charge generation layer 104 injects electrons into one EL layer (103a or 103b) and ) has a function of injecting holes. Therefore, in FIG. 1B, when a voltage is applied to the first electrode 101 so that the potential thereof is higher than that of the second electrode 102, electrons are injected from the charge generation layer 104 into the EL layer 103a and the EL layer 103b. holes are injected into

From the viewpoint of light extraction efficiency, the charge generation layer 104 preferably has a property of transmitting visible light (specifically, the charge generation layer 104 has a visible light transmittance of 40% or more). Also, the charge generation layer 104 functions even if the conductivity is lower than that of the first electrode 101 and the second electrode 102 .

FIG. 1C shows the stacked structure of the EL layer 103 . In FIG. 1C, when the first electrode 101 functions as an anode, the EL layer 103 includes a hole-injection layer 111, a hole-transport layer 112, and a hole-injection layer 111 over the first electrode 101. It has a structure in which a light-emitting layer 113, an electron-transporting layer 114, and an electron-injecting layer 115 are sequentially stacked. Even in the case of having a plurality of EL layers as in the tandem structure shown in FIG. 1B, each EL layer is stacked sequentially from the anode side as described above. Note that when the first electrode 101 is the cathode and the second electrode 102 is the anode, the stacking order is reversed.

Each of the light-emitting layers 113 included in the EL layers (103, 103a, and 103b) includes a light-emitting substance or an appropriate combination of a plurality of substances, and has a structure in which fluorescent light emission or phosphorescent light emission with a desired emission color can be obtained. be able to. Further, the light-emitting layer 113 may have a laminated structure with different emission colors. Note that in this case, different materials may be used for the light-emitting substances and other substances used in the stacked light-emitting layers. Alternatively, a structure in which different emission colors can be obtained from the plurality of EL layers (103a and 103b) shown in FIG. 1B may be employed. In this case also, different materials may be used for the light-emitting substances and other substances used in the respective light-emitting layers.

Further, in the light-emitting device which is one embodiment of the present invention, the emitted light emitted from the EL layers (103, 103a, and 103b) may be resonated between both electrodes to enhance the emitted light. For example, in FIG. 1C, the first electrode 101 is a reflective electrode and the second electrode 102 is a semi-transmissive/semi-reflective electrode, thereby forming a micro optical resonator (microcavity) structure and forming an EL layer. The luminescence obtained from 103 can be enhanced.

Note that when the first electrode 101 of the light-emitting device is a reflective electrode having a laminated structure of a reflective conductive material and a light-transmitting conductive material (transparent conductive film), the film of the transparent conductive film Optical tuning can be achieved by controlling the thickness. Specifically, the inter-electrode distance between the first electrode 101 and the second electrode 102 is approximately mλ/2 (where m is a natural number) with respect to the wavelength λ of light obtained from the light-emitting layer 113. It is preferable to adjust

In order to amplify desired light (wavelength: λ) obtained from the light-emitting layer 113, the optical distance from the first electrode 101 to the region (light-emitting region) of the light-emitting layer 113 from which desired light is obtained, The optical distance from the second electrode 102 to the region (light-emitting region) of the light-emitting layer 113 where desired light is obtained is adjusted to be near (2m′+1)λ/4 (where m′ is a natural number). preferably. Note that the light-emitting region here means a recombination region of holes and electrons in the light-emitting layer 113 .

By performing such optical adjustment, the spectrum of specific monochromatic light obtained from the light-emitting layer 113 can be narrowed, and light emission with good color purity can be obtained.

However, in the above case, strictly speaking, the optical distance between the first electrode 101 and the second electrode 102 is the total thickness from the reflection area of the first electrode 101 to the reflection area of the second electrode 102. can. However, since it is difficult to strictly determine the reflective regions in the first electrode 101 and the second electrode 102, it is possible to assume arbitrary positions of the first electrode 101 and the second electrode 102 as reflective regions. can sufficiently obtain the above effects. Strictly speaking, the optical distance between the first electrode 101 and the light-emitting layer from which desired light is obtained is the optical distance between the reflection region in the first electrode 101 and the light-emitting region in the light-emitting layer from which desired light is obtained. It can be said that it is the distance. However, since it is difficult to strictly determine the reflective region in the first electrode 101 and the light-emitting region in the light-emitting layer from which desired light can be obtained, an arbitrary position of the first electrode 101 can be used as the reflective region and the desired light-emitting region. By assuming that an arbitrary position of the light-emitting layer from which light is obtained is the light-emitting region, the above effects can be sufficiently obtained.

When the light-emitting device shown in FIG. 1C has a microcavity structure, light of different wavelengths (monochromatic light) can be extracted even if the EL layer is shared. Therefore, separate coloring (for example, RGB) for obtaining different emission colors is not necessary, and high definition can be achieved. A combination with a colored layer (color filter) is also possible. In addition, since it is possible to increase the emission intensity of the specific wavelength in the front direction, it is possible to reduce power consumption.

Note that in the light-emitting device which is one embodiment of the present invention, at least one of the first electrode 101 and the second electrode 102 is a light-transmitting electrode (a transparent electrode, a semi-transmissive/semi-reflective electrode, or the like). do. When the light-transmitting electrode is a transparent electrode, the visible light transmittance of the transparent electrode is set to 40% or more. In the case of the semi-transmissive/semi-reflective electrode, the visible light reflectance of the semi-transmissive/semi-reflective electrode should be 20% or more and 80% or less, preferably 40% or more and 70% or less. Moreover, these electrodes preferably have a resistivity of 1×10 ⁻² Ωcm or less.

Further, in the above-described light-emitting device of one embodiment of the present invention, when one of the first electrode 101 and the second electrode 102 is a reflective electrode (reflective electrode), the reflective electrode The light reflectance is 40% or more and 100% or less, preferably 70% or more and 100% or less. Moreover, the electrode preferably has a resistivity of 1×10 ⁻² Ωcm or less.

<<Specific Structure and Manufacturing Method of Light-Emitting Device>>
Next, a specific structure and a manufacturing method of a light-emitting device that is one embodiment of the present invention are described. In addition, in FIGS. 1(A) to 1(D), when the reference numerals are the same, the description is also the same.

<First electrode and second electrode>
As materials for forming the first electrode 101 and the second electrode 102, the following materials can be used in appropriate combination as long as the functions of both electrodes in the above-described element structure can be satisfied. For example, metals, alloys, electrically conductive compounds, mixtures thereof, and the like can be used as appropriate. Specifically, In--Sn oxide (also referred to as ITO), In--Si--Sn oxide (also referred to as ITSO), In--Zn oxide, and In--W--Zn oxide are given. In addition, aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn ), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y ), neodymium (Nd), and alloys containing appropriate combinations thereof can also be used. In addition, elements belonging to Group 1 or Group 2 of the periodic table of elements not exemplified above (e.g., lithium (Li), cesium (Cs), calcium (Ca), strontium (Sr)), europium (Eu), ytterbium Rare earth metals such as (Yb), alloys containing an appropriate combination thereof, graphene, and the like can be used.

In the case where the light-emitting device shown in FIG. 1 includes the EL layer 103 having a stacked-layer structure as shown in FIG. A hole injection layer 111 and a hole transport layer 112 are sequentially laminated by a vacuum deposition method. Further, as in FIG. 1D, when a plurality of EL layers (103a and 103b) having a stacked structure are stacked with the charge generation layer 104 interposed therebetween and the first electrode 101 is an anode, the first electrode Not only are the hole injection layer 111a and the hole transport layer 112a of the EL layer 103a successively laminated on the EL layer 101 by vacuum evaporation, but also the EL layer 103a and the charge generation layer 104 are successively laminated on the EL layer 103a. A hole-injecting layer 111b and a hole-transporting layer 112b of the EL layer 103b are sequentially laminated on the layer 104 in the same manner.

<Hole injection layer and hole transport layer>
The hole injection layers (111, 111a, 111b) are layers for injecting holes from the first electrode 101, which is an anode, and the charge generation layer (104) into the EL layers (103, 103a, 103b). , which is a layer containing a material having a high hole injection property.

Materials with high hole injection properties include transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide. In addition, phthalocyanine compounds such as phthalocyanine (abbreviation: H ₂ Pc) and copper phthalocyanine (abbreviation: CuPc) can be used.

In addition, 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-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), 4, 4′-bis(N-{4-[N′-(3-methylphenyl)-N′-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviation: DNTPD), 1,3,5-tris[ N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation : PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N-(1-naphthyl)- Aromatic amine compounds such as N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1) and the like can be used.

In addition, poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4 -{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA), poly[N,N'-bis(4-butylphenyl)- N,N'-bis(phenyl)benzidine] (abbreviation: Poly-TPD) and the like can be used. Alternatively, poly (3,4-ethylenedioxythiophene) / poly (styrene sulfonic acid) (abbreviation: PEDOT / PSS), polyaniline / poly (styrene sulfonic acid) (abbreviation: PAni / PSS), etc. Molecular compounds and the like can also be used.

A composite material containing a hole-transporting material and an acceptor material (electron-accepting material) can also be used as a material having a high hole-injecting property. In this case, electrons are withdrawn from the hole-transporting material by the acceptor material to generate holes in the hole-injecting layers (111, 111a, 111b), and through the hole-transporting layers (112, 112a, 112b). Holes are injected into the light-emitting layers (113, 113a, 113b). The hole injection layers (111, 111a, 111b) may be formed of a single layer made of a composite material containing a hole-transporting material and an acceptor material (electron-accepting material). The material and the acceptor material (electron-accepting material) may be laminated in separate layers.

The hole transport layers (112, 112a, 112b) transfer holes injected from the first electrode 101 and the charge generation layer 104 to the light emitting layers (113, 113a, 113b) transport layer. The hole-transporting layers (112, 112a, 112b) are layers containing a hole-transporting material. The hole-transporting material used for the hole-transporting layers (112, 112a, 112b) should have a HOMO level that is the same as or close to the HOMO level of the hole-injecting layers (111, 111a, 111b). is preferred.

As an acceptor material used for the hole injection layers (111, 111a, 111b), oxides of metals belonging to groups 4 to 8 of the periodic table can be used. Specific examples include molybdenum oxide, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, tungsten oxide, manganese oxide, and rhenium oxide. Among them, molybdenum oxide is particularly preferred because it is stable even in the atmosphere, has low hygroscopicity, and is easy to handle. In addition, organic acceptors such as quinodimethane derivatives, chloranil derivatives, and hexaazatriphenylene derivatives can be used. Specifically, 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F ₄ -TCNQ), chloranil, 2,3,6,7,10,11 -Hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN) and the like can be used. In particular, a compound such as HAT-CN in which an electron-withdrawing group is bound to a condensed aromatic ring having a plurality of heteroatoms is thermally stable and preferable. In addition, [3] radialene derivatives having an electron-withdrawing group (especially a halogen group such as a fluoro group or a cyano group) are preferable because they have very high electron-accepting properties. 1,2,3-cyclopropanetriylidene tris[4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α',α''-1,2,3-cyclopropanetriylidene tris [2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], α,α′,α″-1,2,3-cyclopropanetriylidenetris[2,3,4 , 5,6-pentafluorobenzeneacetonitrile] and the like.

The hole-transporting material used for the hole-injecting layers (111, 111a, 111b) and the hole-transporting layers (112, 112a, 112b) has a hole mobility of 1×10 ⁻⁶ cm ² /Vs or more. Substances are preferred. Note that any substance other than these can be used as long as it has a higher hole-transport property than electron-transport property.

As the hole-transporting material, a material having a high hole-transporting property such as a π-electron-rich heteroaromatic compound (for example, a compound having a carbazole skeleton or a compound having a furan skeleton) or a compound having an aromatic amine skeleton is preferable.

Specific examples of hole-transporting materials include 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB or α-NPD), N,N′-bis(3 -methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4'-bis[N-(spiro-9,9'- Bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4-phenyl-4′-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3 '-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), N-(9,9-dimethyl-9H-fluoren-2-yl)-N-{9,9-dimethyl-2- [N'-phenyl-N'-(9,9-dimethyl-9H-fluoren-2-yl)amino]-9H-fluoren-7-yl}phenylamine (abbreviation: DFLADFL), N-(9,9- Dimethyl-2-diphenylamino-9H-fluoren-7-yl)diphenylamine (abbreviation: DPNF), 2-[N-(4-diphenylaminophenyl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: : DPASF), 4-phenyl-4′-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 3-[4-(9-phenanthryl)-phenyl]-9-phenyl -9H-carbazole (abbreviation: PCPPn), N-(4-biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-carbazol-3-amine (abbreviation: PCBiF), N-(1,1′-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluorene-2 -amine (abbreviation: PCBBiF), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4 '-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazole-3 -yl)triphenylamine (abbreviation: PCBNBB), 4-phenyldiphenyl-(9-phenyl-9H-carbazol-3-yl)amine (abbreviation: PCA1BP), N,N'-bis(9-phenylcarbazole-3 -yl)-N,N'-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N,N',N''-triphenyl-N,N',N''-tris(9-phenylcarbazole -3-yl)benzene-1,3,5-triamine (abbreviation: PCA3B), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl] Fluorene-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9′-bifluoren-2-amine (abbreviation: PCBASF), 2-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]spiro-9,9′-bifluorene (abbreviation: PCASF), 2,7-bis[N-(4-diphenyl aminophenyl)-N-phenylamino]-spiro-9,9′-bifluorene (abbreviation: DPA2SF), N-[4-(9H-carbazol-9-yl)phenyl]-N-(4-phenyl)phenylaniline (abbreviation: YGA1BP), N,N'-bis[4-(carbazol-9-yl)phenyl]-N,N'-diphenyl-9,9-dimethylfluorene-2,7-diamine (abbreviation: YGA2F), etc. aromatic amine compounds, etc. can be used. Also, 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 4,4′,4″-tris(carbazol-9-yl)triphenylamine ( abbreviation: TCTA), 4,4′,4″-tris[N-(1-naphthyl)-N-phenylamino]triphenylamine (abbreviation: 1′-TNATA), 4,4′,4″- Tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4′,4″-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: m -MTDATA), N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)- N-phenylamino]biphenyl (abbreviation: DPAB), N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)- Compounds having an aromatic amine skeleton such as 4,4′-diamine (abbreviation: DNTPD) and 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B) , 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4′-di(N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)- 9-phenylcarbazole (abbreviation: CzTP), 3,3′-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP), 3-[N-(4-diphenylaminophenyl)-N-phenylamino]- 9-phenylcarbazole (abbreviation: PCzDPA1), 3,6-bis[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA2), 3,6-bis[N- (4-diphenylaminophenyl)-N-(1-naphthyl)amino]-9-phenylcarbazole (abbreviation: PCzTPN2), 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]- 9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N- (1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene ( Abbreviation: TCPB), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA) and other compounds having a carbazole skeleton, 1,3,5-tri(dibenzothiophene-4 -yl)benzene (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4- Compounds having a thiophene skeleton such as [4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), 4,4′,4″-(benzene -1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: Examples include compounds having a furan skeleton such as mmDBFFLBi-II).

Furthermore, poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino) phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA), poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviation: Polymer compounds such as Poly-TPD) can also be used.

However, the hole-transporting material is not limited to the above, and the hole-transporting layer (111, 111a, 111b) and the hole-transporting layer are formed by combining one or a plurality of known various materials as a hole-transporting material. (112, 112a, 112b). The hole transport layers (112, 112a, 112b) may each be formed from a plurality of layers. That is, for example, a first hole transport layer and a second hole transport layer may be laminated.

In the light-emitting device shown in FIG. 1D, the light-emitting layer 113a is formed over the hole-transport layer 112a of the EL layer 103a by a vacuum evaporation method. After the EL layer 103a and the charge generation layer 104 are formed, the light emitting layer 113b is formed on the hole transport layer 112b of the EL layer 103b by vacuum deposition.

<Light emitting layer>
The light-emitting layers (113, 113a, 113b) are layers containing light-emitting substances. Note that as the light-emitting substance, a substance that emits light of blue, purple, blue-violet, green, yellow-green, yellow, orange, red, or the like is used as appropriate. In addition, by using different light-emitting substances for the plurality of light-emitting layers (113a and 113b), it is possible to obtain a configuration in which different emission colors are exhibited (for example, white light emission obtained by combining complementary emission colors). Furthermore, a laminated structure in which one light-emitting layer contains different light-emitting substances may be used.

In addition, the light-emitting layers (113, 113a, 113b) may contain one or more organic compounds (host material, assist material) in addition to the light-emitting substance (guest material). As one or more kinds of organic compounds, one or both of the hole-transporting material and the electron-transporting material described in this embodiment can be used.

The light-emitting substance that can be used for the light-emitting layers (113, 113a, 113b) is not particularly limited, and a light-emitting substance that converts singlet excitation energy into light emission in the visible light region, or a light-emitting substance that converts triplet excitation energy into light emission in the visible light region. can be used. Examples of the light-emitting substance include the following.

Examples of light-emitting substances that convert singlet excitation energy into light emission include substances that emit fluorescence (fluorescent materials). quinoxaline derivatives, quinoxaline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, naphthalene derivatives and the like. Pyrene derivatives are particularly preferred because they have a high emission quantum yield. Specific examples of pyrene derivatives include N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6 -diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: : 1,6FLPAPrn), N,N'-bis(dibenzofuran-2-yl)-N,N'-diphenylpyrene-1,6-diamine (abbreviation: 1,6FrAPrn), N,N'-bis(dibenzothiophene -2-yl)-N,N'-diphenylpyrene-1,6-diamine (abbreviation: 1,6ThAPrn), N,N'-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b ] naphtho[1,2-d]furan)-6-amine] (abbreviation: 1,6BnfAPrn), N,N′-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[ 1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-02), N,N′-(pyrene-1,6-diyl)bis[(6,N-diphenylbenzo[b]naphtho [1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03) and the like.

In addition, 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl- 9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenyl Stilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-( 9H-carbazol-9-yl)-4′-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9- anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), 4-(10-phenyl-9-anthryl)-4′-(9-phenyl-9H-carbazol-3-yl)triphenylamine ( abbreviation: PCBAPA), 4-[4-(10-phenyl-9-anthryl)phenyl]-4′-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPBA), perylene, 2 ,5,8,11-tetra-(tert-butyl)perylene (abbreviation: TBP), N,N''-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis[N ,N′,N′-triphenyl-1,4-phenylenediamine] (abbreviation: DPABPA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H- Carbazol-3-amine (abbreviation: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA) or the like can be used.

Examples of light-emitting substances that convert triplet excitation energy into light emission include substances that emit phosphorescence (phosphorescent materials) and thermally activated delayed fluorescence (TADF) materials that exhibit thermally activated delayed fluorescence. .

Phosphorescent materials include organic metal complexes, metal complexes (platinum complexes), rare earth metal complexes, and the like. Since these exhibit different emission colors (emission peaks) depending on the substance, they are appropriately selected and used as necessary.

Examples of phosphorescent materials that exhibit blue or green color and have an emission spectrum with a peak wavelength of 450 nm or more and 570 nm or less include the following substances.

For example, tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN2]phenyl-κC}iridium (III ) (abbreviation: [Ir(mpptz-dmp) ₃ ]), tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium (III) (abbreviation: [Ir(Mptz) ₃ ]), tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]iridium (III) (abbreviation: [Ir(iPrptz-3b) ₃ ]), tris 4H-triazole skeletons such as [3-(5-biphenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(iPr5btz) ₃ ]), tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(Mptz1-mp) ₃ ]), 1H-triazoles such as tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Prptz1-Me) ₃ ]) organometallic complex having a skeleton, fac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium (III) (abbreviation: [Ir(iPrpmi) ₃ ]), tris[3- (2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium (III) (abbreviation: [Ir(dmpimpt-Me) ₃ ]) having an imidazole skeleton metal complex, bis[2-(4′,6′-difluorophenyl)pyridinato-N,C ^2′ ]iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation: FIr6), bis[2-(4′, 6′-difluorophenyl)pyridinato-N,C ^2′ ]iridium (III) picolinate (abbreviation: Firpic), bis{2-[3′,5′-bis(trifluoromethyl)phenyl]pyridinato-N,C ^{2 '} } iridium (III) picolinate (abbreviation: [Ir(CF ₃ ppy) ₂ (pic)]), bis[2-(4′,6′-difluorophenyl)pyridinato-N,C ^2′ ]iridium (III) Organometallic complexes having a phenylpyridine derivative having an electron-withdrawing group such as acetylacetonate (abbreviation: FIr(acac)) as a ligand, and the like can be mentioned.

Examples of phosphorescent materials that exhibit green or yellow color and have an emission spectrum with a peak wavelength of 495 nm or more and 590 nm or less include the following substances.

For example, tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation [Ir(mpm) ₃ ]), tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) ( Abbreviations: [Ir(tBuppm) ₃ ]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium (III) (abbreviations: [Ir(mppm) ₂ (acac)]), (acetyl acetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium (III) (abbreviation: [Ir(tBuppm) ₂ (acac)]), (acetylacetonato)bis[6-(2-norbornyl )-4-phenylpyrimidinato]iridium (III) (abbreviation: [Ir(nbppm) ₂ (acac)]), (acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4- phenylpyrimidinato]iridium (III) (abbreviation: [Ir(mpmpm) ₂ (acac)]), (acetylacetonato)bis{4,6-dimethyl-2-[6-(2,6-dimethylphenyl) -4-pyrimidinyl-κN ^] phenyl-κC}iridium (III) (abbreviation: [Ir(dmpm-dmp) ₂ (acac)]), (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium (III) (abbreviation: [Ir(dppm) ₂ (acac)]), an organometallic complex having a pyrimidine skeleton such as (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium ( III) (abbreviation: [Ir(mppr-Me) ₂ (acac)]), (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium (III) (abbreviation: [Ir (mppr-iPr) ₂ (acac)]), an organometallic complex having a pyrazine skeleton such as tris(2-phenylpyridinato-N,C ^2′ ) iridium (III) (abbreviation: [Ir(ppy) ₃ ]), bis(2-phenylpyridinato-N,C ^2′ )iridium (III) acetylacetonate (abbreviation: [Ir(ppy) ₂ (acac)]), bis(benzo[h]quinolinato)iridium ( III) acetylacetonate (abbreviation: [Ir(bzq) ₂ (acac)]), tris(benzo[h]quinolinato)iridium (III) (abbreviation: [Ir(bzq) ₃ ]), tris(2-phenylquino linato-N,C ^2′ )iridium(III) (abbreviation: [Ir(pq) ₃ ]), bis(2-phenylquinolinato-N,C ^2′ )iridium(III) acetylacetonate (abbreviation: [Ir (pq) ₂ (acac)]), bis(2,4-diphenyl-1,3-oxazolato-N,C ^2′ )iridium (III) acetylacetonate (abbreviation: [Ir(dpo) ₂ (acac)]), bis{2-[4′-(perfluorophenyl)phenyl]pyridinato-N,C ^2′ }iridium(III) acetylacetonate (abbreviation: [Ir(p- PF-ph) ₂ (acac)]), bis(2-phenylbenzothiazolato-N,C ^2′ ) iridium (III) acetylacetonate (abbreviation: [Ir(bt) ₂ (acac)]), etc. In addition to organometallic complexes, rare earth metal complexes such as tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac) ₃ (Phen)]) can be used.

Examples of phosphorescent materials that exhibit yellow or red color and have an emission spectrum with a peak wavelength of 570 nm or more and 750 nm or less include the following substances.

For example, (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium (III) (abbreviation: [Ir (5mdppm) ₂ (dibm)]), bis[4,6-bis ( 3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium (III) (abbreviation: [Ir(5mdppm) ₂ (dpm)]), (dipivaloylmethanato)bis[4,6-di(naphthalene- 1-yl)pyrimidinato]iridium(III) (abbreviation: [Ir(d1npm) ₂ (dpm)]), an organometallic complex having a pyrimidine skeleton, (acetylacetonato)bis(2,3,5-triphenyl pyrazinato)iridium (III) (abbreviation: [Ir(tppr) ₂ (acac)]), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridium (III) (abbreviation: : [Ir(tppr) ₂ (dpm)]), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq) ₂ (acac)] ) and organometallic complexes having a pyrazine skeleton such as tris(1-phenylisoquinolinato-N,C ^2′ )iridium (III) (abbreviation: [Ir(piq) ₃ ]), bis(1-phenyliso Organometallic complexes having a pyridine skeleton such as quinolinato-N,C ^2′ )iridium (III) acetylacetonate (abbreviation: [Ir(piq) ₂ (acac)]), 2,3,7,8,12 , 13,17,18-octaethyl-21H,23H-porphyrin platinum (II) (abbreviation: [PtOEP]), platinum complexes such as tris(1,3-diphenyl-1,3-propanedionate) (monophenanthroline ) europium (III) (abbreviation: [Eu(DBM) ₃ (Phen)]), tris[1-(2-thenoyl)-3,3,3-trifluoroacetonato](monophenanthroline) europium (III) ( Abbreviations: [Eu(TTA) ₃ (Phen)]) and other rare earth metal complexes.

As the organic compound (host material, assist material) used in the light-emitting layers (113, 113a, 113b), one or a plurality of substances having an energy gap larger than that of the light-emitting substance (guest material) may be selected and used. good. It should be noted that the materials exemplified as the hole-transporting materials described above and the materials exemplified as the electron-transporting materials described later can also be used as such an organic compound (host material, assist material).

When the light-emitting substance is a fluorescent material, an organic compound having a high singlet excited energy level and a low triplet excited energy level is preferably used as the host material. Note that in addition to the hole-transporting material and the electron-transporting material described in this embodiment, a bipolar material can be used as the host material, but any substance that satisfies the above conditions is more preferable. For example, anthracene derivatives and tetracene derivatives are also suitable.

Therefore, host materials combined with fluorescent light-emitting substances include, for example, 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: PCzPA), PCPN, CzPA, 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl] -benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-{4-(9-phenyl-9H-fluoren-9-yl)biphenyl-4′-yl}anthracene (abbreviation: FLPPA), 5,12-diphenyltetracene, 5,12-bis(biphenyl-2-yl)tetracene and the like.

When the light-emitting substance is a phosphorescent material, an organic compound having triplet excitation energy higher than the triplet excitation energy (the energy difference between the ground state and the triplet excited state) of the light-emitting substance may be selected as the host material. Note that in addition to the hole-transporting material and the electron-transporting material described in this embodiment, a bipolar material can be used as the host material, but any substance that satisfies the above conditions is more preferable. For example, condensed polycyclic aromatic compounds such as anthracene derivatives, phenanthrene derivatives, pyrene derivatives, chrysene derivatives, and dibenzo[g,p]chrysene derivatives are also suitable.

Therefore, host materials combined with a phosphorescent light-emitting substance include, for example, 9,10-diphenylanthracene (abbreviation: DAnth), N,N-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl] -9H-carbazol-3-amine (abbreviation: CzA1PA), 4-(10-phenyl-9-anthryl)triphenylamine (abbreviation: DPhPA), YGAPA, PCAPA, 9-(4-{4'-[N- Phenyl-N-(N-phenyl-3-carbazolyl)]amino}phenyl)phenyl-10-phenylanthracene (abbreviation: PCAPBA), N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl- 9H-carbazol-3-amine (abbreviation: 2PCAPA), 6,12-dimethoxy-5,11-diphenylchrysene, N,N,N',N',N'',N'',N''',N '''-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetramine (abbreviation: DBC1), CzPA, 3,6-diphenyl-9-[4-(10-phenyl-9-anthryl ) phenyl]-9H-carbazole (abbreviation: DPCzPA), 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 9,9′-bianthryl (abbreviation: BANT), 9,9′-(stilbene-3,3′- diyl)diphenanthrene (abbreviation: DPNS), 9,9′-(stilbene-4,4′-diyl)diphenanthrene (abbreviation: DPNS2), 1,3,5-tri(1-pyrenyl)benzene (abbreviation: TPB3) ) and the like.

In the case where a plurality of organic compounds are used for the light-emitting layers (113, 113a, and 113b), it is preferable to use a compound that forms an exciplex in combination with a phosphorescent substance. Note that with such a structure, light emission using ExTET (Exciplex-Triplet Energy Transfer), which is energy transfer from an exciplex to a light-emitting substance, can be obtained. In this case, various organic compounds can be used in combination as appropriate. transportable materials) are particularly preferred.

A TADF material is a material that can up-convert (reverse intersystem crossing) a triplet excited state to a singlet excited state with a small amount of thermal energy, and efficiently exhibits light emission (fluorescence) from the singlet excited state. be. In addition, as a condition for efficiently obtaining thermally activated delayed fluorescence, the energy difference between the triplet excitation level and the singlet excitation level is 0 eV or more and 0.2 eV or less, preferably 0 eV or more and 0.1 eV or less. mentioned. In addition, delayed fluorescence in the TADF material refers to light emission having a spectrum similar to that of normal fluorescence and having a significantly long lifetime. Its lifetime is 1×10 ⁻⁶ seconds or more, preferably 1×10 ⁻³ seconds or more.

Examples of TADF materials include fullerenes and derivatives thereof, acridine derivatives such as proflavine, and eosin. Also included are metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd). Examples of metal-containing porphyrins include protoporphyrin-tin fluoride complex (abbreviation: SnF ₂ (Proto IX)), mesoporphyrin-tin fluoride complex (abbreviation: SnF ₂ (Meso IX)), hematoporphyrin-tin fluoride. complex (abbreviation: SnF ₂ (Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (abbreviation: SnF ₂ (Copro III-4Me)), octaethylporphyrin-tin fluoride complex (abbreviation: SnF ₂ (OEP )), ethioporphyrin-tin fluoride complex (abbreviation: SnF ₂ (Etio I)), octaethylporphyrin-platinum chloride complex (abbreviation: PtCl ₂ OEP), and the like.

Other TADF materials include 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine ( Abbreviations: PIC-TRZ), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3, 5-triazine (abbreviation: PCCzPTzn), 2-[4-(10H-phenoxazin-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3- [4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9- Dimethyl-9H-acridin-10-yl)-9H-xanthen-9-one (abbreviation: ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC- DPS), 10-phenyl-10H,10′H-spiro[acridine-9,9′-anthracene]-10′-one (abbreviation: ACRSA) and other π-electron-rich heteroaromatic rings and π-electron-deficient heteroaromatics A heterocyclic compound having a ring can be used. In a substance in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded, both the donor property of the π-electron-rich heteroaromatic ring and the acceptor property of the π-electron-deficient heteroaromatic ring are strengthened. , is particularly preferable because the energy difference between the singlet excited state and the triplet excited state is small.

In addition, when using a TADF material, it can also be used in combination with other organic compounds.

The light-emitting layers (113, 113a, 113b) can be formed by appropriately using the above materials. In addition, the above materials can be used for forming the light-emitting layers (113, 113a, 113b) by combining them with low-molecular-weight materials or high-molecular-weight materials.

In the light-emitting device shown in FIG. 1D, an electron-transporting layer 114a is formed over the light-emitting layer 113a of the EL layer 103a. After the EL layer 103a and the charge generation layer 104 are formed, the electron transport layer 114b is formed on the light emitting layer 113b of the EL layer 103b.

<Electron transport layer>
The electron transport layers (114, 114a, 114b) are layers that transport electrons injected from the second electrode 102 to the light emitting layers (113, 113a, 113b) by the electron injection layers (115, 115a, 115b). . The electron-transporting layers (114, 114a, 114b) are layers containing an electron-transporting material. The electron-transporting material used for the electron-transporting layers (114, 114a, 114b) preferably has an electron mobility of 1×10 ⁻⁶ cm ² /Vs or more. Note that any substance other than these substances can be used as long as it has a higher electron-transport property than hole-transport property.

Examples of electron-transporting materials include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, metal complexes having a thiazole skeleton, oxadiazole derivatives, triazole derivatives, imidazole derivatives, π electron deficient including oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives with quinoline ligands, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, and other nitrogen-containing heteroaromatic compounds A material having a high electron transport property such as a type heteroaromatic compound can be used.

Specific examples of electron-transporting materials include tris(8-quinolinolato)aluminum(III) (abbreviation: Alq ₃ ), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq ₃ ), bis( 10-hydroxybenzo[h]quinolinato)beryllium (II) (abbreviation: BeBq ₂ ), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum (III) (abbreviation: BAlq), bis(8 -quinolinolato) zinc (II) (abbreviation: Znq) and other metal complexes having a quinoline skeleton or benzoquinoline skeleton, bis[2-(2-benzoxazolyl)phenolato]zinc (II) (abbreviation: ZnPBO), bis oxazole skeletons such as [2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ), bis[2-(2-hydroxyphenyl)benzothiazolato]zinc(II) (abbreviation: Zn(BTZ) ₂ ), or Examples thereof include metal complexes having a thiazole skeleton.

In addition to metal complexes, 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-( p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazole -2-yl)phenyl]-9H-carbazole (abbreviation: CO11) and other oxadiazole derivatives, 3-(4′-tert-butylphenyl)-4-phenyl-5-(4″-biphenyl)-1 , 2,4-triazole (abbreviation: TAZ), 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenylyl)-1,2,4-triazole (abbreviation: p-EtTAZ) and other triazole derivatives, 2,2′,2″-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3 -(Dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II) and other imidazole derivatives (including benzimidazole derivatives), and 4,4'-bis(5-methyl benzoxazol-2-yl)stilbene (abbreviation: BzOS) and other oxazole derivatives, bathophenanthroline (abbreviation: Bphen), bathocuproine (abbreviation: BCP), 2,9-bis(naphthalen-2-yl)-4,7- Phenanthroline derivatives such as diphenyl-1,10-phenanthroline (abbreviation: NBPhen), 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[ 3′-(Dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3′-(9H-carbazol-9-yl)biphenyl-3 -yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq- III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), and 6-[3-(dibenzothiophen-4-yl)phenyl] quinoxaline derivatives such as dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), or dibenzoquinoxaline derivatives, 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), Pyridine derivatives such as 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4 ,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazol-9-yl)phenyl] Pyrimidine derivatives such as pyrimidine (abbreviation: 4,6mCzP2Pm), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6- Triazine derivatives such as diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn) can be used.

In addition, poly(2,5-pyridinediyl) (abbreviation: PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviation: PF -Py), poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2′-bipyridine-6,6′-diyl)] (abbreviation: PF-BPy) Molecular compounds can also be used.

Further, the electron transport layers (114, 114a, 114b) are not limited to a single layer, and may have a structure in which two or more layers made of the above substances are laminated.

Next, in the light-emitting device shown in FIG. 1D, an electron-injecting layer 115a is formed over the electron-transporting layer 114a of the EL layer 103a by a vacuum evaporation method. After that, the EL layer 103a and the charge generation layer 104 are formed, and after the electron transport layer 114b of the EL layer 103b is formed, the electron injection layer 115b is formed thereon by vacuum deposition.

<Electron injection layer>
The electron injection layers (115, 115a, 115b) are layers containing substances with high electron injection properties. The electron injection layers (115, 115a, 115b) include alkali metals and alkalis such as lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride ( _CaF2 ), lithium oxide ( _LiOx ), and the like. Earth metals or their compounds can be used. Also, rare earth metal compounds such as erbium fluoride (ErF ₃ ) can be used. Electride may also be used for the electron injection layers (115, 115a, 115b). Examples of the electride include a mixed oxide of calcium and aluminum to which electrons are added at a high concentration. In addition, the substance which comprises the electron transport layer (114, 114a, 114b) mentioned above can also be used.

A composite material obtained by mixing an organic compound and an electron donor (donor) may be used for the electron injection layers (115, 115a, 115b). Such a composite material has excellent electron-injecting and electron-transporting properties because electrons are generated in the organic compound by the electron donor. In this case, the organic compound is preferably a material excellent in transporting generated electrons. Specifically, for example, an electron-transporting material (metal complex and heteroaromatic compounds) can be used. As the electron donor, any substance can be used as long as it exhibits an electron donating property with respect to an organic compound. Specifically, alkali metals, alkaline earth metals, and rare earth metals are preferred, and examples include lithium, cesium, magnesium, calcium, erbium, and ytterbium. Further, alkali metal oxides and alkaline earth metal oxides are preferred, and examples thereof include lithium oxide, calcium oxide and barium oxide. Lewis bases such as magnesium oxide can also be used. An organic compound such as tetrathiafulvalene (abbreviation: TTF) can also be used.

Note that in the case where light obtained from the light-emitting layer 113b is amplified in the light-emitting device illustrated in FIG. It is preferably formed to be less than 1/4 of the wavelength λ. In this case, it can be adjusted by changing the film thickness of the electron transport layer 114b or the electron injection layer 115b.

<Charge generation layer>
In the light-emitting device shown in FIG. 1D, the charge generation layer 104 generates electrons in the EL layer 103a when a voltage is applied between the first electrode (anode) 101 and the second electrode (cathode) . to inject holes into the EL layer 103b. The charge-generating layer 104 may have a structure in which an electron acceptor (acceptor) is added to the hole-transporting material or a structure in which an electron donor (donor) is added to the electron-transporting material. good. Also, both of these configurations may be stacked. Note that by forming the charge-generating layer 104 using the above material, an increase in driving voltage in the case where EL layers are stacked can be suppressed.

In the case where the charge-generating layer 104 has a structure in which an electron acceptor is added to a hole-transporting material, the material described in this embodiment mode can be used as the hole-transporting material. Examples of electron acceptors include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F ₄ -TCNQ) and chloranil. In addition, oxides of metals belonging to groups 4 to 8 in the periodic table can be mentioned. Specific examples include vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide.

In the case where the charge-generating layer 104 has a structure in which an electron donor is added to an electron-transporting material, the materials described in this embodiment can be used as the electron-transporting material. Further, as the electron donor, alkali metals, alkaline earth metals, rare earth metals, metals belonging to Groups 2 and 13 in the periodic table, and oxides and carbonates thereof can be used. Specifically, it is preferable to use lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca), ytterbium (Yb), indium (In), lithium oxide, cesium carbonate, or the like. Alternatively, an organic compound such as tetrathianaphthacene may be used as an electron donor.

<Substrate>
The light-emitting device described in this embodiment can be formed over various substrates. Note that the type of substrate is not limited to a specific one. Examples of substrates include semiconductor substrates (e.g. single crystal substrates or silicon substrates), SOI substrates, glass substrates, quartz substrates, plastic substrates, metal substrates, stainless steel substrates, substrates with stainless steel foil, tungsten substrates, Substrates with tungsten foils, flexible substrates, laminated films, papers containing fibrous materials, or substrate films may be mentioned.

Note that examples of glass substrates include barium borosilicate glass, aluminoborosilicate glass, soda lime glass, and the like. Examples of flexible substrates, laminated films, and base films include plastics such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polyethersulfone (PES), and acrylic resins. Synthetic resin, polypropylene, polyester, polyvinyl fluoride, polyvinyl chloride, polyamide, polyimide, aramid resin, epoxy resin, inorganic deposition film, paper, and the like.

Note that a vacuum process such as an evaporation method or a solution process such as a spin coating method or an inkjet method can be used for manufacturing the light-emitting device described in this embodiment mode. When a vapor deposition method is used, a physical vapor deposition method (PVD method) such as a sputtering method, an ion plating method, an ion beam vapor deposition method, a molecular beam vapor deposition method, or a vacuum vapor deposition method, or a chemical vapor deposition method (CVD method) or the like is used. be able to. In particular, functional layers (hole injection layers (111, 111a, 111b), hole transport layers (112, 112a, 112b), light emitting layers (113, 113a, 113b), electron transport layers ( 114, 114a, 114b), the electron injection layer (115, 115a, 115b)), and the charge generation layer 104, vapor deposition (vacuum vapor deposition, etc.), coating (dip coating, die coating, bar coating, spin coating method, spray coating method, etc.), printing method (inkjet method, screen (stencil printing) method, offset (lithographic printing) method, flexographic (letterpress printing) method, gravure method, microcontact method, nanoimprint method, etc.) It can be formed by a method.

Note that each functional layer (hole injection layers (111, 111a, 111b), hole transport layers (112, 112a, 112b) constituting the EL layers (103, 103a, 103b) of the light-emitting device shown in this embodiment mode , light emitting layers (113, 113a, 113b), electron transport layers (114, 114a, 114b), electron injection layers (115, 115a, 115b)) and charge generation layer 104 are not limited to the above materials, Other materials can be used in combination as long as they can satisfy the functions of each layer. Examples include polymer compounds (oligomers, dendrimers, polymers, etc.), middle-molecular-weight compounds (compounds in the intermediate region between low-molecular-weight and high-molecular-weight compounds: molecular weight 400 to 4000), inorganic compounds (quantum dot materials, etc.), and the like. can. As the quantum dot material, a colloidal quantum dot material, an alloy quantum dot material, a core-shell quantum dot material, a core quantum dot material, or the like can be used.

The structure described in this embodiment can be combined as appropriate with any of the structures described in other embodiments.

(Embodiment 3)
In this embodiment, a light-emitting device that is one embodiment of the present invention will be described. Note that the light-emitting device shown in FIG. 2A is an active matrix light-emitting device in which a transistor (FET) 202 over a first substrate 201 and light-emitting devices (203R, 203G, 203B, and 203W) are electrically connected. 203R, 203G, 203B, and 203W have a common EL layer 204, and the optical distance between the electrodes of each light emitting device varies depending on the color of light emitted by each light emitting device. It has a tuned microcavity structure. In addition, it is a top emission light emitting device in which light emitted from the EL layer 204 is emitted through color filters (206R, 206G, 206B) formed on the second substrate 205. FIG.

In the light-emitting device shown in FIG. 2A, the first electrode 207 is formed to function as a reflective electrode. Also, the second electrode 208 is formed so as to function as a semi-transmissive/semi-reflective electrode. Note that electrode materials for forming the first electrode 207 and the second electrode 208 may be appropriately used with reference to the description of other embodiments.

Further, in FIG. 2A, for example, when the light emitting device 203R is a red light emitting device, the light emitting device 203G is a green light emitting device, the light emitting device 203B is a blue light emitting device, and the light emitting device 203W is a white light emitting device, the light emitting device 203W is a white light emitting device. ), the light-emitting device 203R is adjusted so that the optical distance between the first electrode 207 and the second electrode 208 is 200R, and the light-emitting device 203G is adjusted so that the first electrode 207 and the second electrode 208 is adjusted to have an optical distance of 200G, and the light emitting device 203B is adjusted to have an optical distance of 200B between the first electrode 207 and the second electrode 208 . Note that as shown in FIG. 2B, the conductive layer 210R is stacked on the first electrode 207 in the light-emitting device 203R, and the conductive layer 210G is stacked on the first electrode 207 in the light-emitting device 203G. It can be performed.

Color filters ( 206 R, 206 G, 206 B) are formed on the second substrate 205 . Note that the color filter is a filter that allows a specific wavelength range of visible light to pass through and blocks a specific wavelength range of visible light. Therefore, as shown in FIG. 2A, by providing a color filter 206R that passes only the red wavelength band at a position overlapping the light emitting device 203R, red light emission can be obtained from the light emitting device 203R. In addition, by providing a color filter 206G that passes only the green wavelength band at a position overlapping the light emitting device 203G, green light emission can be obtained from the light emitting device 203G. Also, by providing a color filter 206B that allows only the blue wavelength band to pass through at a position that overlaps with the light emitting device 203B, blue light emission can be obtained from the light emitting device 203B. However, the light emitting device 203W can obtain white light emission without providing a color filter. A black layer (black matrix) 209 may be provided at the end of each color filter. Furthermore, the color filters (206R, 206G, 206B) and black layer 209 may be covered with an overcoat layer using a transparent material.

FIG. 2A shows a light-emitting device having a structure (top emission type) for extracting light from the second substrate 205 side, but the first substrate provided with the FET 202 is used as shown in FIG. 2C. A light emitting device having a structure (bottom emission type) in which light is extracted to the 201 side may be used. Note that in the case of a bottom emission type light emitting device, the first electrode 207 is formed to function as a semi-transmissive/half-reflective electrode, and the second electrode 208 is formed to function as a reflective electrode. At least a translucent substrate is used as the first substrate 201 . Further, the color filters (206R', 206G', 206B') may be provided closer to the first substrate 201 than the light emitting devices (203R, 203G, 203B) as shown in FIG. 2C.

FIG. 2A shows the case where the light-emitting device is a red-light-emitting device, a green-light-emitting device, a blue-light-emitting device, or a white-light-emitting device; however, the light-emitting device that is one embodiment of the present invention is limited to that structure. However, the configuration may include a yellow light emitting device or an orange light emitting device. Materials used for the EL layer (light-emitting layer, hole injection layer, hole transport layer, electron transport layer, electron injection layer, charge generation layer, etc.) for manufacturing these light-emitting devices are shown in other embodiments. The description may be referred to and used as appropriate. In that case, it is also necessary to appropriately select a color filter according to the emission color of the light emitting device.

With the structure as described above, a light-emitting device including a light-emitting device that emits light of a plurality of colors can be obtained.

Note that the structure described in this embodiment can be used in combination with any of the structures described in other embodiments as appropriate.

(Embodiment 4)
In this embodiment, a light-emitting device that is one embodiment of the present invention will be described.

By applying the element structure of the light-emitting device which is one embodiment of the present invention, an active matrix light-emitting device or a passive matrix light-emitting device can be manufactured. Note that an active matrix light-emitting device has a structure in which a light-emitting device and a transistor (FET) are combined. Therefore, both a passive matrix light-emitting device and an active matrix light-emitting device are included in one embodiment of the present invention. Note that the light-emitting device described in other embodiments can be applied to the light-emitting device described in this embodiment.

In this embodiment mode, an active matrix light-emitting device will be described with reference to FIGS.

3A is a top view showing the light emitting device 21, and FIG. 3B is a cross-sectional view taken along the chain line A-A' in FIG. 3A. The active matrix light emitting device includes a pixel portion 302, a driver circuit portion (source line driver circuit) 303, and driver circuit portions (gate line driver circuits) (304a and 304b) provided over a first substrate 301. . The pixel portion 302 and the driver circuit portions (303, 304a, 304b) are sealed between the first substrate 301 and the second substrate 306 with a sealing material 305. FIG.

Further, a lead wiring 307 is provided on the first substrate 301 . The routing wiring 307 is electrically connected to the FPC 308 which is an external input terminal. Note that the FPC 308 transmits external signals (for example, video signals, clock signals, start signals, reset signals, etc.) and potentials to the drive circuit units (303, 304a, 304b). Also, a printed wiring board (PWB) may be attached to the FPC 308 . The state in which these FPCs and PWBs are attached is included in the light emitting device.

Next, FIG. 3B shows a cross-sectional structure of a light-emitting device.

The pixel portion 302 is formed of a plurality of pixels having a FET (switching FET) 311 , a FET (current control FET) 312 , and a first electrode 313 electrically connected to the FET 312 . Note that the number of FETs included in each pixel is not particularly limited, and can be appropriately provided as necessary.

The FETs 309, 310, 311, and 312 are not particularly limited, and for example, staggered or inverted staggered transistors can be applied. Moreover, a transistor structure such as a top-gate type or a bottom-gate type may be used.

The crystallinity of semiconductors that can be used for these FETs 309, 310, 311, and 312 is not particularly limited. or a semiconductor partially having a crystal region) may be used. Note that it is preferable to use a crystalline semiconductor because deterioration of transistor characteristics can be suppressed.

Moreover, as these semiconductors, for example, Group 14 elements, compound semiconductors, oxide semiconductors, organic semiconductors, and the like can be used. Typically, a semiconductor containing silicon, a semiconductor containing gallium arsenide, an oxide semiconductor containing indium, or the like can be used.

The drive circuit section 303 has an FET 309 and an FET 310 . Note that the FET 309 and FET 310 may be formed of a circuit including a unipolar (either N-type or P-type) transistor, or may be formed of a CMOS circuit including an N-type transistor and a P-type transistor. can be Further, a structure having an external driving circuit may be employed.

An end of the first electrode 313 is covered with an insulator 314 . Note that for the insulator 314, an organic compound such as a negative photosensitive resin or a positive photosensitive resin (acrylic resin) or an inorganic compound such as silicon oxide, silicon oxynitride, or silicon nitride can be used. . Preferably, the insulator 314 has a curved surface with a curvature at the upper end or the lower end. Accordingly, the coverage of the film formed over the insulator 314 can be improved.

An EL layer 315 and a second electrode 316 are stacked over the first electrode 313 . The EL layer 315 has a light-emitting layer, a hole-injection layer, a hole-transport layer, an electron-transport layer, an electron-injection layer, a charge generation layer, and the like.

Note that the structure and materials described in other embodiments can be applied to the structure of the light-emitting device 317 described in this embodiment. Although not shown here, the second electrode 316 is electrically connected to the FPC 308 which is an external input terminal.

Although only one light-emitting device 317 is illustrated in the cross-sectional view of FIG. 3B, a plurality of light-emitting devices are arranged in matrix in the pixel portion 302 . In the pixel portion 302, light-emitting devices capable of emitting light of three types (R, G, and B) are selectively formed to form a light-emitting device capable of full-color display. In addition to light emitting devices capable of emitting light of three types (R, G, B), for example, light emitting devices capable of emitting light of white (W), yellow (Y), magenta (M), cyan (C), etc. A device may be formed. For example, by adding a light-emitting device capable of emitting light of several types as described above to a light-emitting device capable of emitting light of three types (R, G, B), effects such as improvement of color purity and reduction of power consumption can be obtained. can be done. Further, a light-emitting device capable of full-color display may be obtained by combining with a color filter. As types of color filters, red (R), green (G), blue (B), cyan (C), magenta (M), yellow (Y), and the like can be used.

The FETs (309, 310, 311, 312) and the light-emitting device 317 on the first substrate 301 are formed by bonding the second substrate 306 and the first substrate 301 together with the sealing material 305. 301 , a second substrate 306 , and a space 318 surrounded by a sealant 305 . Note that the space 318 may be filled with an inert gas (nitrogen, argon, or the like) or an organic substance (including the sealant 305).

Epoxy resin or glass frit can be used for the sealant 305 . Note that it is preferable to use a material that does not transmit moisture and oxygen as much as possible for the sealant 305 . For the second substrate 306, the substrate that can be used for the first substrate 301 can also be used. Therefore, various substrates described in other embodiments can be used as appropriate. As a substrate, in addition to a glass substrate and a quartz substrate, a plastic substrate made of FRP (Fiber-Reinforced Plastics), PVF (Polyvinyl Fluoride), polyester, acrylic resin, or the like can be used. When glass frit is used as the sealant, the first substrate 301 and the second substrate 306 are preferably glass substrates from the viewpoint of adhesiveness.

As described above, an active matrix light-emitting device can be obtained.

Further, when an active matrix type light-emitting device is formed on a flexible substrate, the FET and the light-emitting device may be formed directly on the flexible substrate. After forming, the FET and the light-emitting device may be separated by a separation layer by applying heat, force, laser irradiation, or the like, and transferred to a flexible substrate. As the separation layer, for example, a laminate of inorganic films such as a tungsten film and a silicon oxide film, an organic resin film such as polyimide, or the like can be used. In addition to substrates on which transistors can be formed, flexible substrates include paper substrates, cellophane substrates, aramid film substrates, polyimide film substrates, cloth substrates (natural fibers (silk, cotton, linen), synthetic fibers ( nylon, polyurethane, polyester) or recycled fiber (including acetate, cupra, rayon, recycled polyester), leather substrate, or rubber substrate. By using these substrates, durability and heat resistance are excellent, and weight reduction and thickness reduction can be achieved.

Note that the structure described in this embodiment can be combined with any of the structures described in other embodiments as appropriate.

(Embodiment 5)
In this embodiment, examples of various electronic devices and automobiles completed by applying the light-emitting device of one embodiment of the present invention and the light-emitting device including the light-emitting device of one embodiment of the present invention will be described. Note that the light-emitting device can be mainly applied to a display portion in the electronic devices described in this embodiment.

4A to 4C include a housing 7000, a display portion 7001, a speaker 7003, an LED lamp 7004, operation keys 7005 (including a power switch or an operation switch), connection terminals 7006, Sensor 7007 (force, displacement, position, speed, acceleration, angular velocity, number of rotations, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity , tilt, vibration, smell, or infrared), a microphone 7008, and the like.

FIG. 4A shows a mobile computer, which can have a switch 7009, an infrared port 7010, etc. in addition to those described above.

FIG. 4B shows a portable image reproducing device (for example, a DVD reproducing device) provided with a recording medium, which may include a second display portion 7002, a recording medium reading portion 7011, and the like in addition to the components described above. can.

FIG. 4C shows a digital camera with a television image receiving function, which can have an antenna 7014, a shutter button 7015, an image receiving portion 7016, and the like in addition to the above.

FIG. 4D shows a portable information terminal. The portable information terminal has a function of displaying information on three or more sides of the display portion 7001 . Here, an example in which information 7052, information 7053, and information 7054 are displayed on different surfaces is shown. For example, the user can confirm the information 7053 displayed at a position that can be observed from above the portable information terminal while the portable information terminal is stored in the chest pocket of the clothes. The user can confirm the display without taking out the mobile information terminal from the pocket, and can determine, for example, whether or not to receive a call.

FIG. 4E illustrates a portable information terminal (including a smartphone) which can include a housing 7000, a display portion 7001, operation keys 7005, and the like. Note that the mobile information terminal may be provided with a speaker, a connection terminal, a sensor, and the like. Also, the portable information terminal can display characters and image information on its multiple surfaces. Here, an example of displaying three icons 7050 is shown. Information 7051 indicated by a dashed rectangle can also be displayed on another surface of the display portion 7001 . Examples of the information 7051 include notification of incoming e-mail, SNS, telephone, etc., title of e-mail, SNS, etc., sender name, date and time, remaining battery level, strength of antenna reception, and the like. Alternatively, an icon 7050 or the like may be displayed at the position where the information 7051 is displayed.

FIG. 4F illustrates a large television device (also referred to as a television or a television receiver), which can include a housing 7000, a display portion 7001, and the like. Also, here, a configuration in which the housing 7000 is supported by a stand 7018 is shown. Further, the operation of the television apparatus can be performed by a separate remote controller 7111 or the like. Note that the display portion 7001 may be provided with a touch sensor, and the display portion 7001 may be operated by touching the display portion 7001 with a finger or the like. The remote controller 7111 may have a display section for displaying information output from the remote controller 7111 . A channel and a volume can be operated with operation keys or a touch panel included in the remote controller 7111 , and an image displayed on the display portion 7001 can be operated.

The electronic devices illustrated in FIGS. 4A to 4F can have various functions. For example, a function to display various information (still images, moving images, text images, etc.) on the display unit, a touch panel function, a calendar, a function to display the date or time, a function to control processing by various software (programs). , wireless communication function, function to connect to various computer networks using wireless communication function, function to transmit or receive various data using wireless communication function, read programs or data recorded on recording media It can have a function of displaying on a display portion, and the like. Furthermore, in an electronic device having a plurality of display units, one display unit mainly displays image information, and another display unit mainly displays character information, or a parallax is considered for a plurality of display units. It is possible to have a function of displaying a three-dimensional image by displaying an image that has been drawn, and the like. Furthermore, in electronic devices with an image receiving unit, functions for shooting still images, shooting moving images, functions for correcting shot images automatically or manually, and saving shot images to recording media (external or built into the camera) It can have a function of saving, a function of displaying a captured image on a display portion, and the like. Note that the functions that the electronic devices illustrated in FIGS. 4A to 4F can have are not limited to these, and can have various functions.

FIG. 4G shows a wristwatch-type portable information terminal that can be used as a smart watch, for example. This wristwatch-type portable information terminal includes a housing 7000, a display portion 7001, operation buttons 7022 and 7023, a connection terminal 7024, a band 7025, a microphone 7026, a sensor 7029, a speaker 7030, and the like. The display portion 7001 has a curved display surface and can perform display along the curved display surface. In addition, this portable information terminal can make hands-free calls by mutual communication with a headset capable of wireless communication, for example. Note that the connection terminal 7024 enables mutual data transmission and charging with another information terminal. The charging operation can also be performed by wireless power supply.

A display portion 7001 mounted on a housing 7000 that also serves as a bezel portion has a non-rectangular display area. The display unit 7001 can display an icon 7027 representing time, other icons 7028, and the like. Further, the display portion 7001 may be a touch panel (input/output device) equipped with a touch sensor (input device).

Note that the smart watch illustrated in FIG. 4G can have various functions. For example, a function to display various information (still images, moving images, text images, etc.) on the display unit, a touch panel function, a calendar, a function to display the date or time, a function to control processing by various software (programs). , wireless communication function, function to connect to various computer networks using wireless communication function, function to transmit or receive various data using wireless communication function, read programs or data recorded on recording media It can have a function of displaying on a display portion, and the like.

In addition, inside the housing 7000, there are speakers, sensors (force, displacement, position, speed, acceleration, angular velocity, number of revolutions, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current , voltage, power, radiation, flow, humidity, gradient, vibration, odor or infrared), microphone, etc.

Note that the light-emitting device of one embodiment of the present invention and the display device including the light-emitting device of one embodiment of the present invention can be used for each display portion of the electronic device described in this embodiment, and the electronic device has a long life. can be realized.

Further, as an electronic device to which a light-emitting device is applied, there is a foldable portable information terminal as shown in FIGS. FIG. 5A shows a portable information terminal 9310 in an unfolded state. FIG. 5B shows the portable information terminal 9310 in the middle of changing from one of the unfolded state and the folded state to the other. Further, FIG. 5C shows a portable information terminal 9310 in a folded state. The portable information terminal 9310 has excellent portability in the folded state, and has excellent display visibility due to a seamless wide display area in the unfolded state.

The display portion 9311 is supported by three housings 9315 connected by hinges 9313 . Note that the display portion 9311 may be a touch panel (input/output device) equipped with a touch sensor (input device). In addition, the display portion 9311 can be reversibly transformed from the unfolded state to the folded state by bending between the two housings 9315 via the hinges 9313 . Note that the light-emitting device of one embodiment of the present invention can be used for the display portion 9311 . Moreover, a long-life electronic device can be realized. A display area 9312 in the display portion 9311 is a display area located on the side surface of the portable information terminal 9310 in the folded state. In the display area 9312, information icons, frequently used apps, shortcuts of programs, and the like can be displayed, so that information can be checked and apps can be started smoothly.

6A and 6B show an automobile to which the light emitting device is applied. That is, the light emitting device can be provided integrally with the automobile. Specifically, it can be applied to a part or the whole of a light 5101 (including the rear part of the vehicle body), a tire wheel 5102, and a door 5103 on the outside of an automobile shown in FIG. 6(A). Further, it can be applied to a display portion 5104, a steering wheel 5105, a shift lever 5106, a seat 5107, an inner rear view mirror 5108, etc. inside an automobile shown in FIG. 6B. In addition, you may apply to a part of glass window.

As described above, electronic devices and automobiles to which the light-emitting device or the display device of one embodiment of the present invention is applied can be obtained. In that case, an electronic device with a long life can be realized. Note that applicable electronic devices and automobiles are not limited to those shown in the present embodiment, and can be applied in all fields.

Note that the structure described in this embodiment can be combined with any of the structures described in other embodiments as appropriate.

(Embodiment 6)
In this embodiment, a structure of a lighting device manufactured using a light-emitting device that is one embodiment of the present invention or a light-emitting device that is a part thereof will be described with reference to FIGS.

FIGS. 7A and 7B show examples of cross-sectional views of lighting devices. Note that FIG. 7A shows a bottom emission type lighting device in which light is extracted to the substrate side, and FIG. 7B shows a top emission type lighting device in which light is extracted to the sealing substrate side.

A lighting device 4000 illustrated in FIG. 7A has a light-emitting device 4002 over a substrate 4001 . In addition, a substrate 4003 having unevenness is provided outside the substrate 4001 . The light emitting device 4002 has a first electrode 4004 , an EL layer 4005 and a second electrode 4006 .

The first electrode 4004 is electrically connected with the electrode 4007 and the second electrode 4006 is electrically connected with the electrode 4008 . Further, an auxiliary wiring 4009 electrically connected to the first electrode 4004 may be provided. Note that an insulating layer 4010 is formed on the auxiliary wiring 4009 .

Also, the substrate 4001 and the sealing substrate 4011 are bonded with a sealing material 4012 . A desiccant 4013 is preferably provided between the sealing substrate 4011 and the light emitting device 4002 . Note that since the substrate 4003 has unevenness as shown in FIG. 7A, the extraction efficiency of light generated in the light emitting device 4002 can be improved.

A lighting device 4200 in FIG. 7B has a light-emitting device 4202 over a substrate 4201 . The light emitting device 4202 has a first electrode 4204 , an EL layer 4205 and a second electrode 4206 .

First electrode 4204 is electrically connected to electrode 4207 and second electrode 4206 is electrically connected to electrode 4208 . Further, an auxiliary wiring 4209 electrically connected to the second electrode 4206 may be provided. Further, an insulating layer 4210 may be provided under the auxiliary wiring 4209 .

A substrate 4201 and an uneven sealing substrate 4211 are bonded with a sealing material 4212 . A barrier film 4213 and a planarizing film 4214 may be provided between the sealing substrate 4211 and the light emitting device 4202 . Note that since the sealing substrate 4211 has unevenness as shown in FIG. 7B, the extraction efficiency of light generated in the light emitting device 4202 can be improved.

Further, as an application example of these lighting devices, there is a ceiling light for indoor lighting. Ceiling lights include a type directly attached to the ceiling, a type embedded in the ceiling, and the like. Note that such a lighting device is configured by combining a light emitting device with a housing or a cover.

In addition, it can be applied to a foot light or the like that can improve the safety of the foot by irradiating the floor with light. Footlights are useful, for example, for use in bedrooms, stairs, corridors, and the like. In that case, the size and shape can be appropriately changed according to the size and structure of the room. In addition, a stationary lighting device configured by combining a light emitting device and a support base is also possible.

Moreover, it is also possible to apply it as a sheet-shaped illuminating device (sheet-shaped illumination). Since the sheet-like lighting is used by attaching it to a wall surface, it does not take up much space and can be used for a wide range of purposes. In addition, it is easy to increase the area. In addition, it can also be used for walls and housings having curved surfaces.

In addition to the above, a lighting device having a function as furniture can be obtained by applying the light-emitting device of one embodiment of the present invention or a light-emitting device that is part of the furniture to a part of furniture provided in a room. can be done.

As described above, various lighting devices to which the light-emitting device is applied can be obtained. Note that these lighting devices are included in one embodiment of the present invention.

Further, the structure described in this embodiment can be combined with any of the structures described in other embodiments as appropriate.

<<Synthesis Example 1>>
In this example, an organometallic complex, bis(benzo[f]naphtho[2,1-h]quinoxalin-5-yl-, which is one embodiment of the present invention represented by Structural Formula (100) in Embodiment 1 κC ⁵ , κN ⁴ )(2,2,6,6-tetramethyl-3,5-heptanedionato-κ ² O,O′)iridium(III) (abbreviation: [Ir(bnq) ₂ (dpm)]) A synthesis method will be described. The structure of [Ir(bnq) ₂ (dpm)] is shown below.

<Step 1: Synthesis of benzo[f]naphtho[2,1-h]quinoxaline (abbreviation: Hbnq)>
First, 2.1 g (7.7 mmol) of chrysene-5,6-dione, 0.56 g (9.3 mmol) of ethylenediamine, and 20 mL of ethanol were placed in a 100 mL three-necked flask, and heated and stirred at 80° C. for 12 hours under a nitrogen atmosphere. The resulting mixture was suction filtered, and the filter cake was washed with ethanol. The obtained solid was purified by silica gel column chromatography. Toluene was used as a developing solvent. The resulting fraction was concentrated to obtain the desired product (white solid 0.98 g, yield 45%). The synthesis scheme of step 1 is shown in formula (a-1) below.

<Step 2: Synthesis of [Ir(bnq) ₂ (dpm)]>
Next, 0.98 g (3.5 mmol) of the ligand Hbnq obtained in step 1 above, 0.47 g (1.6 mmol) of iridium chloride hydrate, and 35 mL of dimethylformamide (DMF) are placed in a three-necked flask, and the inside of the flask is Nitrogen was substituted. The mixture was heated and stirred at 160° C. for 5 hours. After a predetermined time had passed, 0.67 g (6.4 mmol) of sodium carbonate and 0.88 g (4.8 mmol) of Hdpm were added to the mixture, and the mixture was heated and stirred at 140°C for 9 hours. Next, this mixture was subjected to suction filtration, and the filtrate was washed with water and ethanol to obtain a red solid.

Next, dichloromethane was added to this red solid, and suction filtration was performed to remove an insoluble solid. The filtrate was subjected to suction filtration through a filter material laminated with celite/alumina, and the filtrate was concentrated to obtain the desired product (deep red solid 0.42 g, yield 28%). The synthesis scheme of step 2 is shown in formula (a-2) below.

Protons ( ¹ H) in the deep red solid obtained in step 2 above were measured by nuclear magnetic resonance (NMR). The values obtained are shown below. Also, a ¹ H-NMR chart is shown in FIG. From this, it was found that [Ir(bnq) ₂ (dpm)], which is an organometallic complex of one embodiment of the present invention represented by the above structural formula (100), was obtained in this synthesis example. . In FIG. 8, the proton at about 11 ppm is assigned to the proton at the 14th position of benzonaphthoquinoxaline (bnq), and is bound to the central metal Ir among the nitrogens of the benzonaphthoquinoxaline (bnq) skeleton that coordinates to the central metal. A strong hydrogen bond is formed between the free nitrogen and the condensed hydrocarbon hydrogen (14-position proton of benzonaphthoquinoxaline (bnq)). Therefore, it was found that protons at about 11 ppm are significantly shifted downfield.

¹ H-NMR. δ(CDCl ₃ ): 0.89 (s, 18H), 5.65 (s, 1H), 6.52 (d, 2H), 7.13 (t, 2H), 7.70 (t, 2H) , 7.88 (t, 2H), 8.07 (d, 2H), 8.10 (d, 2H), 8.20 (d, 2H), 8.70 (d, 2H), 8.80 ( d, 2H), 9.01 (d, 2H), 11.03 (d, 2H).

Next, the ultraviolet-visible absorption spectrum (hereinafter simply referred to as "absorption spectrum") and emission spectrum of a dichloromethane solution of [Ir(bnq) ₂ (dpm)] were measured.

An ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, model V550) was used to measure the absorption spectrum. For the measurement of the emission spectrum, a fluorescence photometer (FS920, manufactured by Hamamatsu Photonics Co., Ltd.) was used, and a degassed dichloromethane solution (0.011 mmol/L) was placed in a quartz cell, and the measurement was performed at room temperature.

FIG. 9 shows the measurement results of the obtained absorption spectrum and emission spectrum. The horizontal axis represents wavelength, and the vertical axis represents absorption intensity and emission intensity. In addition, the thin solid line in FIG. 9 indicates the absorption spectrum, and the thick solid line indicates the emission spectrum. The absorption spectrum shown in FIG. 9 is obtained by subtracting the absorption spectrum measured by putting only dichloromethane in a quartz cell from the absorption spectrum measured by putting a dichloromethane solution (0.011 mmol/L) in a quartz cell.

From the results in FIG. 9, the organometallic complex [Ir(bnq) ₂ (dpm)] which is one embodiment of the present invention exhibited an emission peak at 660 nm, and red light emission was observed from the dichloromethane solution.

In this example, bis(benzo[f]naphtho[2,1-h]quinoxalin-5-yl-κC ⁵ ,κN ⁴ ) (2 ,2,6,6-tetramethyl-3,5-heptanedionato-κ ² O,O′) iridium (III) (abbreviation: [Ir(bnq) ₂ (dpm)]) (structural formula (100)) emits light. Light-emitting device 1 used in the layer was fabricated, and bis(dibenzo[f,h]quinoxalin-5-yl-κC ⁵ ,κN ⁴ )(2,4-pentanedionato-κ ² was used as a comparative light-emitting device. A comparative light-emitting device 2 was fabricated using O,O′)iridium(III) (abbreviation: [Ir(dbq) ₂ (acac)]) (structural formula (200)) for the light-emitting layer. Element structures, manufacturing methods, and characteristics of the light-emitting device 1 and the comparative light-emitting device 2 will be described. Note that FIG. 10 shows the element structure of the light-emitting device used in this example, and Table 1 shows the specific configuration. Chemical formulas of materials used in this example are shown below.

<<Fabrication of light-emitting device>>
In the light-emitting device shown in this example, a hole-injection layer 911, a hole-transport layer 912, a light-emitting layer 913, an electron-transport layer 914, a hole-injection layer 912, a light-emitting layer 913, an electron-transport layer 914, and It has a structure in which electron injection layers 915 are sequentially stacked and a second electrode 903 is stacked on the electron injection layers 915 .

First, a first electrode 901 was formed over a substrate 900 . The electrode area was 4 mm ² (2 mm×2 mm). A glass substrate was used as the substrate 900 . The first electrode 901 was formed by sputtering indium tin oxide containing silicon oxide (ITSO) to a thickness of 70 nm.

Here, as a pretreatment, the surface of the substrate was washed with water, baked at 200° C. for 1 hour, and then subjected to UV ozone treatment for 370 seconds. After that, the substrate was introduced into a vacuum deposition apparatus whose interior was evacuated to about 1×10 ⁻⁴ Pa, and vacuum baked at 170° C. for 30 minutes in a heating chamber in the vacuum deposition apparatus. Allow to cool to some extent.

Next, a hole-injection layer 911 was formed over the first electrode 901 . The hole injection layer 911 is formed by reducing the pressure in the vacuum deposition apparatus to 1×10 ⁻⁴ Pa and then adding 1,3,5-tri(dibenzothiophen-4-yl)benzene (abbreviation: DBT3P-II) and molybdenum oxide. was formed by co-evaporating DBT3P-II:molybdenum oxide=2:1 (mass ratio) so that the film thickness would be 75 nm.

Next, a hole-transport layer 912 was formed over the hole-injection layer 911 . The hole transport layer 912 was formed using 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP) by evaporation to a thickness of 20 nm.

Next, a light-emitting layer 913 was formed over the hole-transport layer 912 .

In the light-emitting layer 913 of the light-emitting device 1, 2mDBTBPDBq-II is used as a host material, PCBBiF is used as an assist material, and an organometallic complex of one embodiment of the present invention, [Ir(bnq) ₂ (dpm)], and the weight ratio was 2mDBTBPDBq-II:PCBBiF:[Ir(bnq) ₂ (dpm)]=0.75:0.25:0.10. In addition, the film thickness was set to 40 nm.

The light-emitting layer 913 of Comparative Light-Emitting Device 2 uses 2mDBTBPDBq-II as the host material, PCBBiF as the assist material, and [Ir(dbq) ₂ (acac)] as the guest material (phosphorescent material). was co-evaporated such that 2mDBTBPDBq-II:PCBBiF:[Ir(dbq) ₂ (acac)]=0.75:0.25:0.075. In addition, the film thickness was set to 40 nm.

Next, an electron-transporting layer 914 was formed over the light-emitting layer 913 . In the electron-transporting layer 914, 2mDBTBPDBq-II has a thickness of 30 nm and 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen) has a thickness of 15 nm. It was formed by sequentially vapor-depositing.

Next, an electron injection layer 915 was formed over the electron transport layer 914 . The electron injection layer 915 was formed by vapor deposition using lithium fluoride (LiF) to a thickness of 1 nm.

Next, a second electrode 903 was formed over the electron injection layer 915 . The second electrode 903 was formed by vapor deposition of aluminum so as to have a thickness of 200 nm. Note that the second electrode 903 functions as a cathode in this embodiment.

Through the above steps, a light-emitting device having an EL layer sandwiched between a pair of electrodes was formed over the substrate 900 . Note that the hole-injection layer 911, the hole-transport layer 912, the light-emitting layer 913, the electron-transport layer 914, and the electron-injection layer 915 described in the above steps are functional layers forming the EL layer in one embodiment of the present invention. In the vapor deposition process in the manufacturing method described above, a vapor deposition method using a resistance heating method was used in all cases.

Also, the light emitting device fabricated as shown above is encapsulated by another substrate (not shown). When sealing using another substrate (not shown), another substrate (not shown) coated with a sealant that is cured by ultraviolet light is placed on the substrate 900 in a nitrogen atmosphere glove box. The substrates were fixed, and the substrates were adhered so that the sealing agent adhered to the periphery of the light emitting device formed on the substrate 900 . At the time of sealing, ultraviolet light of 365 nm was irradiated at 6 J/cm ² to solidify the sealant, and the sealant was stabilized by heat treatment at 80° C. for 1 hour.

<<Operating characteristics of light-emitting devices>>
The operating characteristics of each fabricated light-emitting device were measured. The measurement was performed at room temperature (atmosphere maintained at 25°C). 11 to 14 show the results.

Table 2 below shows the main initial characteristic values of each light-emitting device near 1000 cd/m ² .

From the above results, it can be seen that the light-emitting device 1 exhibits good device characteristics.

FIG. 15 shows emission spectra obtained when a current density of 2.5 mA/cm ² was applied to the light-emitting device 1 and the comparative light-emitting device 2 . In FIG. 15, the light-emitting device 1 exhibits an emission spectrum with a peak near 650 nm originating from the light emitted from the organometallic complex [Ir(bnq) ₂ (dpm)] contained in the light-emitting layer 913 . Further, Comparative Light-Emitting Device 2 exhibits an emission spectrum having a peak near 630 nm due to the light emitted from the organometallic complex [Ir(dbq) ₂ (acac)] contained in the light-emitting layer 913 . The maximum emission wavelength of the light-emitting device 1 is shifted in the longer wavelength direction than that of the comparative light-emitting device 2 . This is because, in the light-emitting device ₁ , the central metal (9 Group or Group 10: Conjugation of benzonaphthoquinoxaline (bnq) rather than dibenzoquinoxaline (dbq) by forming a hydrogen bond between the nitrogen not bonded to Ir, Pt) and the hydrogen of the condensed ring of the bnq backbone This is because the Therefore, it can be said that the organometallic complex of one embodiment of the present invention is suitable for shifting the maximum emission wavelength to a longer wavelength and adjusting the emission wavelength to a red emission region.

Next, a reliability test was performed on the light-emitting device 1 and the comparative light-emitting device 2. FIG. FIG. 16 shows the results of the reliability test. In FIG. 16, the vertical axis indicates the normalized luminance (%) when the initial luminance is 100%, and the horizontal axis indicates the driving time (h) of the device. In the reliability test, the current density was set to 75 mA/cm ² and the light emitting device was driven.

As a result of the reliability test, it was found that the light-emitting device 1 exhibited higher reliability than the comparative light-emitting device 2. This can be said to be an effect of using the organometallic complex [Ir(bnq) ₂ (dpm)] (Structural Formula (100)), which is one embodiment of the present invention, for the light-emitting layer of the light-emitting device 1 . In [Ir(dbq) ₂ (acac)], the nitrogen that does not bond to the central metal (group 9 or group 10: Ir, Pt) among the nitrogens of the dibenzoquinoxaline (dbq) skeleton of the ligand is There is a possibility of forming a hydrogen bond between the condensed hydrocarbon hydrogen of the adjacent host molecule, etc., causing proton transfer between molecules in the process of forming an excited state or transferring excited energy. may be a factor in the deterioration of On the other hand, [Ir(bnq) ₂ (dpm)] in this example has a central metal (group 9 or 10: Ir, Pt ) and the hydrogen of the condensed ring of the bnq skeleton can form a hydrogen bond, so that the structure can be stabilized. Therefore, it can be said that the reliability of the light-emitting device 1 is improved.

<<Synthesis Example 2>>
In this example, the organometallic complex, bis(benzo[a,i]naphtho[2,1-c]phenazine-10-, which is one embodiment of the present invention represented by Structural Formula (118) in Embodiment 1, yl-κC ¹⁰ , κN ¹¹ )(2,2,6,6-tetramethyl-3,5-heptanedionato-κ ² O,O′) iridium (III) (abbreviation: [Ir(dbnphz) ₂ (dpm)] ) will be described. The structure of [Ir(dbnphz) ₂ (dpm)] is shown below.

<Step 1: Synthesis of dibenzo[a,i]naphtho[2,1-c]phenazine (abbreviation: Hdbnphz)>
First, 1.0 g (4.0 mmol) of chrysene-5,6-dione, 0.67 g (4.3 mmol) of 2,3-diaminonaphthalene, and 20 mL of ethanol were placed in a reaction vessel and heated under reflux for 5 hours. After a predetermined period of time, the resulting mixture was suction filtered, and the solid was washed with ethanol. This solid was dissolved in heated toluene, and suction-filtered through a filtering material laminated in order of celite, alumina, and celite. The obtained filtrate was concentrated and recrystallized with a mixed solvent of toluene and ethanol to obtain the desired product (1.1 g, yield 74%). The synthesis scheme of step 1 is shown in formula (b-1) below.

<Step 2: Synthesis of [Ir(dbnphz) ₂ (dpm)]>
Next, 1.1 g (2.9 mmol) of the ligand Hdbnphz obtained in step 2 above, 0.39 g (1.3 mmol) of iridium chloride hydrate, and 30 mL of dimethylformamide (DMF) were added to the reaction vessel, and the inside of the vessel was After purging with nitrogen, the mixture was heated and stirred at 160° C. for 7.5 hours. After a predetermined time had passed, 0.55 g (5.2 mmol) of sodium carbonate and 0.72 g (3.9 mmol) of dipivaloylmethane were added, and the mixture was heated and stirred at 140° C. for 14 hours. Next, this mixture was subjected to suction filtration, and the obtained solid was washed with water and ethanol.

Next, this solid was purified by silica gel column chromatography using dichloromethane as a developing solvent, and the resulting fraction was concentrated to obtain a solid. This solid was washed with hot toluene to obtain 133 mg of the desired product.

Next, the resulting filtrate was concentrated and purified by silica gel column chromatography using toluene as a developing solvent. Next, the solid obtained by concentrating the obtained fraction was recrystallized using a mixed solvent of toluene and ethanol to obtain the desired product (80 mg) (total yield: 213 mg, yield: 14%). The synthesis scheme of step 2 is shown in formula (b-2) below.

Protons ( ¹ H) in the black solid obtained in step 2 above were measured by nuclear magnetic resonance (NMR). The values obtained are shown below. A ¹ H-NMR chart is shown in FIG. Therefore, in Synthesis Example 2, [Ir(dbnphz) ₂ (dpm)]), which is an organometallic complex of one embodiment of the present invention represented by the above structural formula (118), was obtained. have understood.

¹ H-NMR δ (CDCl ₃ ): 0.52 (s, 18H), 5.04 (s, 1H), 6.80 (d, 2H), 6.97 (t, 2H), 7.48 ( d, 2H), 7.59 (t, 2H), 7.74 (t, 2H), 7.88 (d, 2H), 7.98 (t, 2H), 8.06 (d, 2H), 8.10 (d, 2H), 8.26 (d, 4H), 8.64 (d, 2H), 9.13 (s, 2H), 9.19 (s, 2H), 11.21 (d , 2H).

Next, the ultraviolet-visible absorption spectrum (hereinafter simply referred to as "absorption spectrum") and emission spectrum of a dichloromethane solution of [Ir(dbnphz) ₂ (dpm)] were measured.

An ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, Model V550) was used to measure the absorption spectrum, and a dichloromethane solution (0.013 mmol/L) was placed in a quartz cell and the measurement was performed at room temperature. In addition, an absolute PL quantum yield measurement device (C11347-01, manufactured by Hamamatsu Photonics Co., Ltd.) was used to measure the emission spectrum. I made a measurement.

FIG. 18 shows the measurement results of the obtained absorption spectrum and emission spectrum. The horizontal axis represents wavelength, and the vertical axis represents absorption intensity and emission intensity. The absorption spectrum shown in FIG. 18 shows the result of subtracting the absorption spectrum measured by putting only dichloromethane in the quartz cell from the absorption spectrum measured by putting the dichloromethane solution in the quartz cell.

As shown in FIG. 18, near-infrared luminescence having an emission peak at 865 nm was observed from the [Ir(dbnphz) ₂ (dpm)] dichloromethane solution. Note that the results in FIG. 18 confirm that the Stokes shift in [Ir(dbnphz) ₂ (dpm)] is large. A large Stokes shift makes it possible to shift the maximum emission wavelength in the longer wavelength direction.

In addition, the bnq skeleton can have a structure in which conjugation spreads due to the condensed polycyclic ring. Further, by condensing the pyrazine ring of the bnq skeleton with a naphthyl group, the π conjugated system is extended and the LUMO level can be stabilized, the maximum emission wavelength can be shifted in the longer wavelength direction.

In this example, as a light-emitting device which is one embodiment of the present invention, a light-emitting device 3 using [Ir(dbnphz) ₂ (dpm)] (structural formula (118)) described in Example 3 for a light-emitting layer was manufactured. Then, the results of measuring the device characteristics will be described. The element structure of the light-emitting device used in this example is similar to the element structure of the light-emitting device shown in FIG. 3 as shown. Chemical formulas of materials used in this example are shown below.

<<Operating Characteristics of Light-Emitting Device 3>>
The operating characteristics of the fabricated light-emitting device 3 were measured. The measurement was performed at room temperature (atmosphere maintained at 25°C). 19 shows the current density-radiant emittance characteristics of the light-emitting device 3, FIG. 20 shows the voltage-current density characteristics, FIG. 21 shows the current density-radiant flux characteristics, FIG. Quantum efficiency characteristics are shown in FIG. Here, the radiant emittance, radiant flux, and external quantum efficiency were calculated using radiance on the assumption that the light distribution characteristics of the device were Lambertian.

Table 4 below shows the main initial characteristic values of the light-emitting device 3 at around 0.11 W/sr/m ² .

Further, FIG. 24 shows an emission spectrum when a current is passed through the light-emitting device 3 at a current density of 15 mA/cm ² . A near-infrared spectroradiometer (SR-NIR, manufactured by Topcon Corporation) was used to measure the emission spectrum. In FIG. 24, the light-emitting device 3 exhibits an emission spectrum having a peak near 870 nm due to the light emitted from the organometallic complex [Ir(dbnphz) ₂ (dpm)] contained in the light-emitting layer 913 . The half width of the spectrum is 63 nm. When this half-value width is converted into energy, it is about 0.10 eV, which is quite narrow as light emission derived from an organometallic complex. Since this characteristic leads to effective emission of light with a wavelength of 700 nm or more, it can be said to be useful as a light source for sensor applications.

Next, a reliability test for the light emitting device 3 was performed. FIG. 25 shows the results of the reliability test. In FIG. 25, the vertical axis indicates the normalized luminance (%) when the initial luminance is 100%, and the horizontal axis indicates the drive time (h) of the device. In the reliability test, the current density was set to 75 mA/cm ² and the light emitting device was driven.

The reliability test results showed that the light-emitting device 3 exhibited high reliability. This can be said to be an effect of using the organometallic complex [Ir(dbnphz) ₂ (dpm)] (Structural Formula (108)), which is one embodiment of the present invention, for the light-emitting layer of the light-emitting device 3 . [Ir(dbnphz) ₂ (dpm)] is a nitrogen that does not bond to the central metal (Group 9 or Group 10: Ir, Pt) among the nitrogens of the benzonaphthoquinoxaline (bnq) skeleton of the ligand due to the molecular structure. , and the hydrogen of the condensed ring of the bnq skeleton, the structure can be stabilized, so that strong hydrogen bonding with adjacent molecules does not occur. Therefore, it can be said that the reliability of the light emitting device 3 is improved.

101: first electrode, 102: second electrode, 103: EL layer, 103a, 103b: EL layer, 104: charge generation layer, 111, 111a, 111b: hole injection layer, 112, 112a, 112b: positive Hole transport layer 113, 113a, 113b: light emitting layer 114, 114a, 114b: electron transport layer 115, 115a, 115b: electron injection layer 200R, 200G, 200B: optical distance 201: first substrate 202 : transistor (FET), 203R, 203G, 203B, 203W: light emitting device, 204: EL layer, 205: second substrate, 206R, 206G, 206B: color filter, 206R', 206G', 206B': color filter, 207: first electrode, 208: second electrode, 209: black layer (black matrix), 210R, 210G: conductive layer, 301: first substrate, 302: pixel section, 303: drive circuit section (source line drive circuit), 304a, 304b: drive circuit section (gate line driving circuit), 305: sealing material, 306: second substrate, 307: lead-out wiring, 308: FPC, 309: FET, 310: FET, 311: FET, 312: FET, 313: first electrode, 314: insulator, 315: EL layer, 316: second electrode, 317: light emitting device, 318: space, 900: substrate, 901: first electrode, 902: EL layer, 903: Second electrode, 911: Hole injection layer, 912: Hole transport layer, 913: Light emitting layer, 914: Electron transport layer, 915: Electron injection layer, 4000: Lighting device, 4001: Substrate 4002: Light emitting device 4003: Substrate 4004: First electrode 4005: EL layer 4006: Second electrode 4007: Electrode 4008: Electrode 4009: Auxiliary wiring 4010: Insulating layer 4011: Sealing substrate, 4012: sealing material, 4013: desiccant, 4200: lighting device, 4201: substrate, 4202: light emitting device, 4204: first electrode, 4205: EL layer, 4206: second electrode, 4207: electrode , 4208: electrode, 4209: auxiliary wiring, 4210: insulating layer, 4211: sealing substrate, 4212: sealing material, 4213: barrier film, 4214: flattening film, 5101: light, 5102: wheel, 5103: door, 5104 : display unit, 5105: steering wheel, 5106: shift lever, 5107: seat, 5108: inner rear view mirror, 7000: housing, 7001: display unit, 7002: second display unit, 7003: speaker, 7004: LED lamp, 7005: operation keys, 7006: connection terminal, 7007: sensor, 7008: microphone, 7009: switch, 7010: infrared port, 7011: recording medium reading unit, 7014: antenna, 7015: shutter button, 7016: image receiving unit, 7018: Stand 7022, 7023: Operation button 7024: Connection terminal 7025: Band 7026: Microphone 7027: Icon representing time 7028: Other icons 7029: Sensor 7030: Speaker 7052, 7053, 7054: Information 9310: Personal digital assistant 9311: Display unit 9312: Display area 9313: Hinge 9315: Housing

Claims (10)

An organometallic complex represented by General Formula (G2).

(wherein R ¹ to R ¹⁰ are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, or a substituted or unsubstituted and R ⁹ and R ¹⁰ may combine with each other to form a substituted or unsubstituted saturated or unsaturated ring having 3 to 24 carbon atoms, and L represents a monoanionic ligand.) In claim 1 ,
The monoanionic ligand includes a monoanionic bidentate chelate ligand having a β-diketone structure, a monoanionic bidentate chelate ligand having a carboxyl group, and a monoanionic monoanionic ligand having a phenolic hydroxyl group. or a monoanionic bidentate chelating ligand in which both coordinating elements are nitrogen, or a bidentate ligand that forms a metal-carbon bond with iridium by cyclometallation is an organometallic complex. In claim 1 or claim 2 ,
The monoanionic ligand is an organometallic complex represented by any one of the following general formulas (L1) to (L7).

(wherein R ⁵¹ to R ⁸⁹ are each independently hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a halogeno group, a vinyl group, a substituted or unsubstituted haloalkyl group having 1 to 6 carbon atoms, represents a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, a substituted or unsubstituted alkylthio group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and A ¹ to A ¹³ each independently represents an sp ^2- hybridized carbon bonding to nitrogen or hydrogen, or an sp ^2- hybridized carbon having a substituent, the substituent being an alkyl group having 1 to 6 carbon atoms, a halogeno group, or a represents either a haloalkyl group of 6 or a phenyl group.) An organometallic complex represented by the general formula (G3).

(wherein R ¹ to R ¹³ are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, or a substituted or unsubstituted and R ⁹ and R ¹⁰ may combine with each other to form a substituted or unsubstituted saturated or unsaturated ring having 3 to 24 carbon atoms.) An organometallic complex represented by Structural Formula (100) or Structural Formula (118).

A light-emitting device comprising the organometallic complex according to claim 1 . Having a light-emitting layer between a pair of electrodes,
A light-emitting device, wherein the light-emitting layer comprises the organometallic complex according to claim 1 . A light emitting device according to claim 6 or claim 7 ;
either the transistor or the substrate;
A light-emitting device having a light emitting device according to claim 8 ;
any one of a microphone, a camera, operation buttons, an external connection part, or a speaker,
electronic equipment. a light emitting device according to claim 8 ;
any one of a housing, a cover, or a support;
lighting device.

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