JP5072293B2 - Quinoxaline derivative, and light-emitting element, light-emitting device, and electronic device using quinoxaline derivative - Google Patents

Description

  The present invention relates to a quinoxaline derivative, and a light-emitting element, a light-emitting device, and an electronic device using the quinoxaline derivative.

  Organic compounds have a variety of material systems compared to inorganic compounds, and materials having various functions may be synthesized by molecular design. Because of these advantages, in recent years, attention has been focused on photoelectronics and electronics using functional organic materials.

  For example, a solar cell, a light emitting element, an organic transistor, etc. are mentioned as an example of the electronic device which used the organic compound as a functional organic material. These are devices utilizing the electrical properties and optical properties of organic compounds, and particularly light emitting elements are making remarkable progress.

  The light emitting mechanism of a light emitting element is a molecule in which electrons injected from the cathode and holes injected from the anode are recombined at the emission center of the light emitting layer by applying a voltage with the light emitting layer sandwiched between a pair of electrodes. It is said that when excitons are formed and the molecular excitons return to the ground state, they emit energy and emit light. Singlet excitation and triplet excitation are known as excited states, and light emission is considered to be possible through either excited state.

  With respect to such a light emitting element, there are many problems depending on the material in improving the element characteristics, and improvement of the element structure, material development, and the like have been performed in order to overcome these problems.

  The most basic structure of the light emitting element is a thin film having a total thickness of about 100 nm in which a hole transport layer made of a hole transporting organic compound and an electron transport light emitting layer made of an electron transporting organic compound are laminated. A structure sandwiched between electrodes is known (for example, see Non-Patent Document 1).

  When voltage is applied to the light-emitting element described in Non-Patent Document 1, light emission from the organic compound having light-emitting properties and electron-transporting properties can be obtained.

  In the light-emitting element described in Non-Patent Document 1, functional separation is performed in which hole transport is performed by a hole transport layer, and electron transport and light emission are performed by an electron transport layer. However, various interactions (for example, formation of an exciplex) occur at the interface between the stacked layers, and as a result, the emission spectrum may change or the emission efficiency may decrease.

  In order to improve the change in emission spectrum and the decrease in emission efficiency due to the interaction at the interface, a light-emitting element with further functional separation was considered. For example, a light-emitting element having a structure in which a light-emitting layer is sandwiched between a hole transport layer and an electron transport layer has been proposed (see, for example, Non-Patent Document 2).

  In the light emitting device as described in Non-Patent Document 2, in order to further suppress the interaction generated at the interface, the light emitting layer is formed using a bipolar organic compound having both electron transporting property and hole transporting property. It is preferable to form.

  However, most organic compounds are monopolar materials that are biased toward hole transporting or electron transporting.

  Therefore, development of a bipolar organic compound having both electron transporting properties and hole transporting properties has been demanded.

Patent Document 1 describes a bipolar quinoxaline derivative. However, characteristics such as heat resistance are not yet sufficient, and development of more diverse bipolar organic compounds is required.
C. W. Tan, 1 other, Applied Physics Letters, vol. 51, no. 12, 913-915 (1987) Chihaya Adachi, 3 others, Japanese Journal of Applied Physics, vol. 27, no. 2, L269-L271 (1988) International Publication No. 2004/094389 Pamphlet

  In view of the above problems, an object of the present invention is to provide a novel bipolar organic compound. In particular, an object is to provide a bipolar organic compound having excellent heat resistance. It is another object of the present invention to provide an electrochemically stable bipolar organic compound.

  It is another object of the present invention to provide a light-emitting element and a light-emitting device with low driving voltage and low power consumption by using the bipolar organic compound of the present invention. It is another object of the present invention to provide a light-emitting element and a light-emitting device having excellent heat resistance by using the bipolar organic compound of the present invention. It is another object of the present invention to provide a light-emitting element and a light-emitting device having a long lifetime by using the bipolar organic compound of the present invention.

  It is another object of the present invention to provide an electronic device with low power consumption, high heat resistance, and long life by using the bipolar organic compound of the present invention.

  One aspect of the present invention is a quinoxaline derivative represented by the following general formula (1).

(Wherein R ^{1 to} R ¹² may be the same as or different from each other, and are each a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an acyl group, an acyl group, a dialkylamino group, a diarylamino group, or a substituent. Or an unsubstituted vinyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group, and R ⁹ and R ¹⁰ , R ¹⁰ and R ¹¹ , R ¹¹ and R ¹² may be bonded to each other to form a condensed ring, and Ar ¹ represents a substituted or unsubstituted biphenyl group, or a substituted or unsubstituted terphenyl group, and Ar ² represents a substituted or unsubstituted phenyl. Represents a group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group, or a substituted or unsubstituted monocyclic heterocyclic group.)

  One aspect of the present invention is a quinoxaline derivative represented by the following general formula (2).

(In the formula, R ^{9 to} R ¹² may be the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an acyl group, an dialkylamino group, a diarylamino group, or a substituent. Or an unsubstituted vinyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group, and R ⁹ and R ¹⁰ , R ¹⁰ and R ¹¹ , R ¹¹ and R ¹² may be bonded to each other to form a condensed ring, and Ar ¹ represents a substituted or unsubstituted biphenyl group, or a substituted or unsubstituted terphenyl group, and Ar ² represents a substituted or unsubstituted phenyl. Represents a group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group, or a substituted or unsubstituted monocyclic heterocyclic group.)

  One aspect of the present invention is a quinoxaline derivative represented by the following general formula (3).

(In the formula, R ^{9 to} R ¹² may be the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an acyl group, an dialkylamino group, a diarylamino group, or a substituent. Or an unsubstituted vinyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group, and R ⁹ and R ¹⁰ , R ¹⁰ and R ¹¹ , R ¹¹ and R ¹² may be bonded to each other to form a condensed ring, A represents a substituent represented by Structural Formula (4) or Structural Formula (5), and Ar ² represents a substituted or unsubstituted phenyl group. Represents a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group, or a substituted or unsubstituted monocyclic heterocyclic group.)

  One aspect of the present invention is a quinoxaline derivative represented by the following general formula (6).

(In the formula, R ^{9 to} R ¹² may be the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an acyl group, an dialkylamino group, a diarylamino group, or a substituent. Or an unsubstituted vinyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group, and R ⁹ and R ¹⁰ , R ¹⁰ and R ¹¹ , R ¹¹ and R ¹² may be bonded to each other to form a condensed ring, A represents a substituent represented by Structural Formula (7) or Structural Formula (8), and B represents a hydrogen atom or Structural Formula (7). Or a substituent represented by the structural formula (8).)

  One aspect of the present invention is a quinoxaline derivative represented by the following general formula (9).

Wherein A represents a substituent represented by Structural Formula (10) or Structural Formula (11), and B represents a hydrogen atom, or a substituent represented by Structural Formula (10) or Structural Formula (11). To express.)

  One aspect of the present invention is a quinoxaline derivative represented by the following structural formula (14).

  One aspect of the present invention is a quinoxaline derivative represented by the following structural formula (39).

  Another embodiment of the present invention is a light-emitting element using the above quinoxaline derivative. Specifically, a light-emitting element having the above-described quinoxaline derivative between a pair of electrodes.

  Another embodiment of the present invention is a light-emitting element including a light-emitting layer between a pair of electrodes, and the light-emitting layer includes the above-described quinoxaline derivative.

  Another embodiment of the present invention is a light-emitting element including a light-emitting layer between a pair of electrodes, and the light-emitting layer includes the above-described quinoxaline derivative and a fluorescent substance.

  Another embodiment of the present invention is a light-emitting element including a light-emitting layer between a pair of electrodes, and the light-emitting layer includes the above-described quinoxaline derivative and a phosphorescent substance.

In the above structure, the phosphorescent substance is preferably an organometallic complex including a structure represented by the general formula (101).
(Wherein R ^{1 to} R ⁵ each represent hydrogen, a halogen element, an acyl group, an alkyl group, an alkoxyl group, an aryl group, a cyano group, or a heterocyclic group. Ar represents an aryl group or a heterocyclic group. M represents a Group 9 element or a Group 10 element.)

The phosphorescent substance is preferably an organometallic complex represented by the general formula (104).
(Wherein R ^{1 to} R ⁵ each represent hydrogen, a halogen element, an acyl group, an alkyl group, an alkoxyl group, an aryl group, a cyano group, or a heterocyclic group. Ar represents an aryl group or a heterocyclic group. M represents a Group 9 element or a Group 10 element, n = 2 when M is a Group 9 element, and n = 1 when M is a Group 10 element L is a beta diketone It represents either a monoanionic ligand having a structure, a monoanionic bidentate chelate ligand having a carboxyl group, or a monoanionic bidentate chelate ligand having a phenolic hydroxyl group. )

In particular, an organometallic complex represented by the general formula (105) is preferable.
(In the formula, R ¹¹ represents any of an alkyl group having 1 to 4 carbon atoms. R ^{12 to} R ¹⁵ are each a hydrogen atom, a halogen element, an acyl group, an alkyl group, an alkoxyl group, an aryl group, or a cyano group. R ^{16 to} R ¹⁹ each represent hydrogen, an acyl group, an alkyl group, an alkoxyl group, an aryl group, a heterocyclic group, or an electron-withdrawing substituent. M represents a Group 9 or Group 10 element, n = 2 when M is a Group 9 element, and n = 1 when M is a Group 10. L is a beta diketone. It represents either a monoanionic ligand having a structure, a monoanionic bidentate chelate ligand having a carboxyl group, or a monoanionic bidentate chelate ligand having a phenolic hydroxyl group. )

In particular, an organometallic complex represented by the general formula (106) is preferable.
(In the formula, R ^{22 to} R ³⁴ each represent hydrogen, a halogen element, an acyl group, an alkyl group, an alkoxyl group, an aryl group, a cyano group, a heterocyclic group, or an electron-withdrawing substituent. Represents a Group 9 element or a Group 10 element, and M represents a Group 9 element or a Group 10 element, when M is a Group 9 element, n = 2, and when M is a Group 10 element. n = 1 L is a monoanionic ligand having a beta diketone structure, a monoanionic bidentate chelate ligand having a carboxyl group, or a monoanionic bidentate having a phenolic hydroxyl group Any one of chelate ligands.)

  In the above structure, the emission spectrum peak of the phosphorescent substance is preferably 560 nm to 700 nm.

  In addition, a light-emitting device of the present invention includes a layer containing a light-emitting substance between a pair of electrodes, a light-emitting element containing the quinoxaline derivative in the layer containing the light-emitting substance, and a control unit that controls light emission of the light-emitting element. It is characterized by having. Note that a light-emitting device in this specification includes an image display device, a light-emitting device, or a light source (including a lighting device). In addition, a module in which a connector such as an FPC (Flexible Printed Circuit) or TAB (Tape Automated Bonding) tape or TCP (Tape Carrier Package) is attached to the panel, a TAB tape or a module having a printed wiring board at the end of TCP, Alternatively, a module in which an IC (integrated circuit) is directly mounted on a light emitting element by a COG (Chip On Glass) method is included in the light emitting device.

  An electronic device using the light-emitting element of the present invention for the display portion is also included in the category of the present invention. Therefore, an electronic device according to the present invention includes a display portion, and the display portion includes the above-described light emitting element and a control unit that controls light emission of the light emitting element.

  The quinoxaline derivative of the present invention is bipolar and excellent in both electron transport properties and hole transport properties. The quinoxaline derivative of the present invention has a high glass transition point and excellent heat resistance. The quinoxaline derivative of the present invention is stable against electrochemical oxidation and reduction.

  Further, since the quinoxaline derivative of the present invention has bipolar properties, a light-emitting element and a light-emitting device with low driving voltage and low power consumption can be obtained by using the quinoxaline derivative for a light-emitting element.

  In addition, since the quinoxaline derivative of the present invention has a high glass transition point, a light-emitting element and a light-emitting device with high heat resistance can be obtained by using the quinoxaline derivative for a light-emitting element.

  Further, since the quinoxaline derivative of the present invention is stable against electrochemical oxidation and reduction, a light-emitting element and a light-emitting device having a long lifetime can be obtained by using the quinoxaline derivative for a light-emitting element.

  In addition, by using the quinoxaline derivative of the present invention, an electronic device with low power consumption, high heat resistance, and long life can be obtained.

  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 it is easily understood by those skilled in the art that modes and details can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the description of the embodiments below.

(Embodiment 1)
The quinoxaline derivative of the present invention is represented by the following general formula (1).

(Wherein R ^{1 to} R ¹² may be the same as or different from each other, and are each a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an acyl group, an acyl group, a dialkylamino group, a diarylamino group, or a substituent. Or an unsubstituted vinyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group, and R ⁹ and R ¹⁰ , R ¹⁰ and R ¹¹ , R ¹¹ and R ¹² may be bonded to each other to form a condensed ring, and Ar ¹ represents a substituted or unsubstituted biphenyl group, or a substituted or unsubstituted terphenyl group, and Ar ² represents a substituted or unsubstituted phenyl. Represents a group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group, or a substituted or unsubstituted monocyclic heterocyclic group.)

  In the general formula (1), the biphenyl group having a substituent, the terphenyl group having a substituent, and the monocyclic heterocyclic group having a substituent each preferably have an alkyl group or a phenyl group as the substituent. . Examples of the alkyl group include a methyl group, an ethyl group, an isopropyl group, and a tert-butyl group.

  In particular, a quinoxaline derivative represented by the following general formula (2) is preferable.

(In the formula, R ^{9 to} R ¹² may be the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an acyl group, an dialkylamino group, a diarylamino group, or a substituent. Or an unsubstituted vinyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group, and R ⁹ and R ¹⁰ , R ¹⁰ and R ¹¹ , R ¹¹ and R ¹² may be bonded to each other to form a condensed ring, and Ar ¹ represents a substituted or unsubstituted biphenyl group, or a substituted or unsubstituted terphenyl group, and Ar ² represents a substituted or unsubstituted phenyl. Represents a group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group, or a substituted or unsubstituted monocyclic heterocyclic group.)

  In particular, a quinoxaline derivative represented by the following general formula (3) is preferable.

(In the formula, R ^{9 to} R ¹² may be the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an acyl group, an dialkylamino group, a diarylamino group, or a substituent. Or an unsubstituted vinyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group, and R ⁹ and R ¹⁰ , R ¹⁰ and R ¹¹ , R ¹¹ and R ¹² may be bonded to each other to form a condensed ring, A represents a substituent represented by Structural Formula (4) or Structural Formula (5), and Ar ² represents a substituted or unsubstituted phenyl group. Represents a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group, or a substituted or unsubstituted monocyclic heterocyclic group.)

  In particular, a quinoxaline derivative represented by the following general formula (6) is preferable.

(In the formula, R ^{9 to} R ¹² may be the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an acyl group, an dialkylamino group, a diarylamino group, or a substituent. Or an unsubstituted vinyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group, and R ⁹ and R ¹⁰ , R ¹⁰ and R ¹¹ , R ¹¹ and R ¹² may be bonded to each other to form a condensed ring, A represents a substituent represented by Structural Formula (7) or Structural Formula (8), and B represents a hydrogen atom or Structural Formula (7). Or a substituent represented by the structural formula (8).)

  In particular, a quinoxaline derivative represented by the following general formula (9) is preferable.

Wherein A represents a substituent represented by Structural Formula (10) or Structural Formula (11), and B represents a hydrogen atom, or a substituent represented by Structural Formula (10) or Structural Formula (11). To express.)

  Specific examples of the quinoxaline derivative of the present invention include quinoxaline derivatives represented by structural formulas (14) to (65). However, the present invention is not limited to these.

  As a synthesis method of the quinoxaline derivative of the present invention, various reactions can be applied. For example, it can manufacture by performing the synthesis reaction shown to the following reaction scheme (A-1) and (A-2).

  First, a quinoxaline skeleton is formed by a condensation reaction of dibenzyl substituted with a halogen atom X and 1,2-diaminobenzene. Examples of the halogen atom include bromine, iodine, and chlorine, but bromine is preferable in view of ease of handling and appropriate reactivity.

The obtained halogen-substituted quinoxaline is coupled with 2 equivalents of a diarylamine (Ar ¹ —NH—Ar ² ) using a palladium catalyst or monovalent copper in the presence of a base, to thereby achieve the target of the present invention. Quinoxaline derivatives can be synthesized. As the base, an inorganic base such as potassium carbonate or sodium carbonate, an organic base such as metal alkoxide, or the like can be used. As the palladium catalyst, palladium acetate, palladium chloride, bis (dibenzylideneacetone) palladium and the like can be used.

Incidentally, diaryl amine in the above scheme ^(Ar 1 -NH-Ar ²⁾ can be synthesized by the schemes, for example, the following.

First, when Ar ¹ is a biphenyl group, as shown in the following synthesis scheme (A-3), 1 equivalent in the presence of a base with respect to halogen-substituted biphenyl substituted at the 2-position, 3-position or 4-position with halogen The target arylamine (Ar ¹ —NH—Ar ² ; Ar ¹ is a biphenyl group) is obtained by coupling the arylamine (Ar ² —NH ₂ ) using a palladium catalyst or monovalent copper. be able to. As the base, an inorganic base such as potassium carbonate or sodium carbonate, an organic base such as metal alkoxide, or the like can be used. As the palladium catalyst, palladium acetate, palladium chloride, bis (dibenzylideneacetone) palladium and the like can be used.

In the case where Ar ¹ is a biphenyl group and Ar ² is also a biphenyl group, as shown in the following synthesis scheme (A-4), in the presence of a base, diphenylamine in which both two phenyl groups are halogen-substituted, By coupling 2 equivalents of phenylboronic acid using a palladium catalyst or a nickel catalyst, the target arylamine (Ar ¹ —NH—Ar ² ; both Ar ¹ and Ar ² are biphenyl groups) can also be obtained. As the base, an inorganic base such as potassium carbonate or sodium carbonate, an organic base such as metal alkoxide, or the like can be used. As the palladium catalyst, palladium acetate, palladium chloride, bis (dibenzylideneacetone) palladium and the like can be used. In the case of this method, there is an advantage that N, N-di (4-biphenylyl) amine can be synthesized without using 4-aminobiphenyl, which is a harmful substance to the human body.

On the other hand, when synthesizing an arylamine (Ar ¹ —NH—Ar ² ) in which Ar ¹ is a terphenyl group, as shown in the following synthesis scheme (A-5), first, the 2-position, 3-position or 4-position is Substitution of halogen-substituted aniline by coupling 1 equivalent of biphenylboronic acid substituted with a boronic acid group at the 2nd, 3rd or 4th position using a palladium catalyst or nickel catalyst in the presence of a base. Various terphenylamines with different positions can be synthesized. Then, as shown in the following synthesis scheme (A-6), 1 equivalent of the terphenylamine obtained above in the presence of a base with respect to the halogen-substituted arene (Ar ² -X) is added to the palladium catalyst or The target arylamine (Ar ¹ —NH—Ar ² ; Ar ¹ is a terphenyl group) can be obtained by coupling using valent copper. As the base, an inorganic base such as potassium carbonate or sodium carbonate, an organic base such as metal alkoxide, or the like can be used. As the palladium catalyst, palladium acetate, palladium chloride, bis (dibenzylideneacetone) palladium and the like can be used.

In the case where Ar ¹ is a terphenyl group and the benzene ring at the center of the terphenyl group is substituted with an amino group, as shown in the following synthesis scheme (A-7), first, two sites are halogenated. A terphenylamine in which the benzene ring at the center of the terphenyl group is substituted with an amino group by coupling 2 equivalents of phenylboronic acid to the substituted aniline in the presence of a base using a palladium catalyst or a nickel catalyst. Is synthesized. Then, as shown in the following synthesis scheme (A-8), 1 equivalent of the obtained terphenylamine was added to the palladium catalyst or monovalent to the halogen-substituted arene (Ar ² -X) in the presence of a base. By coupling using copper, the target arylamine (Ar ¹ —NH—Ar ² ; Ar ¹ is a terphenyl group) can be obtained. As the base, an inorganic base such as potassium carbonate or sodium carbonate, an organic base such as metal alkoxide, or the like can be used. As the palladium catalyst, palladium acetate, palladium chloride, bis (dibenzylideneacetone) palladium and the like can be used.

  Note that the quinoxaline derivative of the present invention is precipitated as a precipitate by the synthesis reaction shown in the above synthesis scheme (A-2), and thus can be purified by recrystallization. That is, since it is possible to avoid mixing of impurities accompanying extraction or the like, no complicated or complicated purification process is required. Therefore, the quinoxaline derivative of the present invention can be obtained in a highly pure state.

  Further, the quinoxaline derivative of the present invention is bipolar and excellent in both electron transport property and hole transport property. Therefore, good electrical characteristics can be obtained by using the quinoxaline derivative of the present invention for an electronic device. Further, since the quinoxaline derivative of the present invention has a high glass transition point and excellent heat resistance, an electronic device having excellent heat resistance can be obtained by using the quinoxaline derivative of the present invention for an electronic device. In addition, since the quinoxaline derivative of the present invention is stable against electrochemical oxidation and reduction, an electronic device having a long life can be obtained by using the quinoxaline derivative of the present invention for an electronic device.

(Embodiment 2)
One mode of a light-emitting element using the quinoxaline derivative of the present invention is described below with reference to FIG.

  The light-emitting element of the present invention has a plurality of layers between a pair of electrodes. The plurality of layers have a high carrier injection property and carrier transport so that a light emitting region is formed at a position away from the electrode, that is, a carrier (carrier) is recombined at a position away from the electrode. The layers are formed by combining layers made of highly specific materials.

  In this embodiment, the light-emitting element includes a first electrode 102, a first layer 103, a second layer 104, a third layer 105, and a fourth layer 106 that are sequentially stacked over the first electrode 102. And a second electrode 107 provided thereon. Note that in this embodiment mode, the first electrode 102 functions as an anode and the second electrode 107 functions as a cathode.

  The substrate 101 is used as a support for the light emitting element. As the substrate 101, for example, glass or plastic can be used. Note that other materials may be used as long as the light-emitting element functions as a support in the manufacturing process.

  As the first electrode 102, a metal, an alloy, a conductive compound, a mixture thereof, or the like with a high work function (specifically, 4.0 eV or more) is preferably used. Specifically, for example, indium tin oxide (ITO), indium tin oxide containing silicon, and IZO (Indium Zinc Oxide) in which 2 to 20 wt% zinc oxide (ZnO) is mixed with indium oxide. And indium oxide (IWZO) containing 0.5 to 5 wt% of tungsten oxide and 0.1 to 1 wt% of zinc oxide. These conductive metal oxide films are usually formed by sputtering, but may be formed by applying a sol-gel method or the like. In addition, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd ) Or a nitride of a metal material (for example, titanium nitride: TiN).

The first layer 103 is a layer containing a substance having a high hole injection property. Molybdenum oxide (MoOx), vanadium oxide (VOx), ruthenium oxide (RuOx), tungsten oxide (WOx), manganese oxide (MnOx), or the like can be used. In addition, phthalocyanine compounds such as phthalocyanine (abbreviation: H ₂ Pc) and copper phthalocyanine (CuPC), or polymers such as poly (ethylenedioxythiophene) / poly (styrenesulfonic acid) (PEDOT / PSS) Also, the first layer 103 can be formed.

  Alternatively, a composite material formed by combining an organic compound and an inorganic compound may be used for the first layer 103. In particular, in a composite material including an organic compound and an inorganic compound that exhibits an electron accepting property with respect to the organic compound, electrons are transferred between the organic compound and the inorganic compound, so that the carrier density increases. Excellent injection and hole transport properties. In this case, the organic compound is preferably a material excellent in hole transport. Specifically, an aromatic amine-based organic compound or a carbazole-based organic compound is preferable. Moreover, you may use an aromatic hydrocarbon as an organic compound. The inorganic compound may be any substance that exhibits an electron accepting property with respect to an organic compound, and specifically, an oxide of a transition metal is preferable. For example, titanium oxide (TiOx), vanadium oxide (VOx), molybdenum oxide (MoOx), tungsten oxide (WOx), rhenium oxide (ReOx), ruthenium oxide (RuOx), chromium oxide (CrOx) Metal oxides such as zirconium oxide (ZrOx), hafnium oxide (HfOx), tantalum oxide (TaOx), silver oxide (AgOx), and manganese oxide (MnOx) can be used. When a composite material formed by combining an organic compound and an inorganic compound is used for the first layer 103, it is possible to make ohmic contact with the first electrode 102; therefore, the first electrode regardless of the work function The material to form can be selected.

The substance forming the second layer 104 is preferably a substance having a high hole-transport property, specifically, an aromatic amine-based compound (that is, a compound having a benzene ring-nitrogen bond). As a widely used material, 4,4′-bis [N- (3-methylphenyl) -N-phenylamino] biphenyl and its derivative 4,4′-bis [N- (1-naphthyl)- N-phenylamino] biphenyl (hereinafter referred to as NPB), 4,4 ′, 4 ″ -tris (N, N-diphenyl-amino) triphenylamine, 4,4 ′, 4 ″ -tris [N— And starburst aromatic amine compounds such as (3-methylphenyl) -N-phenylamino] triphenylamine. The substances described here are mainly substances having a hole mobility of 10 ⁻⁶ cm ² / Vs or higher. Note that other than these substances, any substance that has a property of transporting more holes than electrons may be used. Note that the second layer 104 is not limited to a single layer, and may be a mixed layer of the above substances or a stack of two or more layers.

  The third layer 105 is a layer containing a light-emitting substance. In this embodiment mode, the third layer 105 includes the quinoxaline derivative of the present invention described in Embodiment Mode 1. Since the quinoxaline derivative of the present invention emits blue to blue-green light, it can be suitably used for a light-emitting element as a light-emitting substance.

The fourth layer 106 is formed using a substance having a high electron-transport property, such as tris (8-quinolinolato) aluminum (abbreviation: Alq), tris (5-methyl-8-quinolinolato) aluminum (abbreviation: Almq ₃ ), bis (10− Hydroxybenzo [h] -quinolinato) beryllium (abbreviation: BeBq ₂ ), bis (2-methyl-8-quinolinolato) -4-phenylphenolato-aluminum (abbreviation: BAlq), and other metals having a quinoline skeleton or a benzoquinoline skeleton It is a layer made of a complex or the like. In addition, bis [2- (2-hydroxyphenyl) -benzoxazolate] zinc (abbreviation: Zn (BOX) ₂ ), bis [2- (2-hydroxyphenyl) -benzothiazolate] zinc (abbreviation: Zn ( A metal complex having an oxazole-based or thiazole-based ligand such as BTZ) ₂ ) can also be used. 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), 3- (4-tert-butylphenyl) -4-phenyl-5 (4-Biphenylyl) -1,2,4-triazole (abbreviation: TAZ), 3- (4-tert-butylphenyl) -4- (4-ethylphenyl) -5- (4-biphenylyl) -1,2 , 4-triazole (abbreviation: p-EtTAZ), bathophenanthroline (abbreviation: BPhen), bathocuproin (abbreviation: BCP), and the like can also be used. The substances mentioned here are mainly substances having an electron mobility of 10 ⁻⁶ cm ² / Vs or higher. Note that a substance other than the above substances may be used for the fourth layer 106 as long as it has a property of transporting more electrons than holes. The fourth layer 106 is not limited to a single layer, and may be a stack of two or more layers formed using the above substances.

  As a material for forming the second electrode 107, a metal, an alloy, an electrically conductive compound, a mixture thereof, or the like having a low work function (specifically, 3.8 eV or less) can be used. Specific examples of such a cathode material include elements belonging to Group 1 or Group 2 of the periodic table of elements, that is, alkali metals such as lithium (Li) and cesium (Cs), and magnesium (Mg), calcium (Ca), Examples thereof include alkaline earth metals such as strontium (Sr), alloys containing these (MgAg, AlLi), rare earth metals such as europium (Eu) and ytterbium (Yb), and alloys containing these. However, by providing a layer having a function of accelerating electron injection between the second electrode 107 and the light-emitting layer by stacking with the second electrode, regardless of the work function, Al, Ag, Various conductive materials such as ITO and ITO containing silicon can be used for the second electrode 107.

Note that as a layer having a function of promoting electron injection, an alkali metal or alkaline earth metal compound such as lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF ₂ ), or the like is used. Can do. In addition, a layer made of a substance having an electron transporting property containing an alkali metal, an alkaline earth metal, an alkali metal compound, or an alkaline earth metal compound, for example, lithium oxide (LiOx) or nitriding in Alq A material containing magnesium (MgOx), magnesium (Mg), lithium (Li), or the like can be used.

  The first layer 103, the second layer 104, the third layer 105, and the fourth layer 106 may be formed by various methods such as an ink jet method or a spin coat method in addition to a vapor deposition method. I do not care. Moreover, you may form using the different film-forming method for each electrode or each layer.

  The light-emitting element of the present invention having the above structure is a third layer that contains a highly light-emitting substance because a current flows due to a potential difference generated between the first electrode 102 and the second electrode 107. In the layer 105, holes and electrons recombine to emit light. That is, a light emitting region is formed in the third layer 105.

  Light emission is extracted outside through one or both of the first electrode 102 and the second electrode 107. Therefore, one or both of the first electrode 102 and the second electrode 107 is formed using a light-transmitting substance. In the case where only the first electrode 102 is formed using a light-transmitting substance, light emission is extracted from the substrate side through the first electrode 102 as illustrated in FIG. In the case where only the second electrode 107 is formed using a light-transmitting substance, light emission is extracted from the side opposite to the substrate through the second electrode 107 as illustrated in FIG. In the case where both the first electrode 102 and the second electrode 107 are made of a light-transmitting substance, light is emitted from the first electrode 102 and the second electrode 107 as shown in FIG. And is taken out from both the substrate side and the opposite side of the substrate.

  Note that the structure of the layers provided between the first electrode 102 and the second electrode 107 is not limited to the above. A structure in which a light emitting region in which holes and electrons are recombined is provided in a portion away from the first electrode 102 and the second electrode 107 so that quenching caused by the proximity of the light emitting region and the metal is suppressed. Anything other than the above may be used.

In other words, the layered structure of the layers is not particularly limited, and a substance having a high electron transporting property or a substance having a high hole transporting property, a substance having a high electron injecting property, a substance having a high hole injecting property, or a bipolar property (electron and hole) A layer made of a substance having a high transportability), a hole blocking material, and the like may be freely combined with the quinoxaline derivative of the present invention.

  A light-emitting element shown in FIG. 2 includes a first layer 303 made of a substance having a high electron-transport property, a second layer 304 containing a light-emitting substance, a hole-transport property, and the first electrode 302 functioning as a cathode. A third layer 305 made of a high substance, a fourth layer 306 made of a substance having a high hole-injecting property, and a second electrode 307 functioning as an anode are sequentially stacked. Reference numeral 301 denotes a substrate.

  In this embodiment mode, a light-emitting element is manufactured over a substrate made of glass, plastic, or the like. A passive light-emitting device can be manufactured by manufacturing a plurality of such light-emitting elements over one substrate. Alternatively, for example, a thin film transistor (TFT) may be formed over a substrate made of glass, plastic, or the like, and a light-emitting element may be formed over an electrode electrically connected to the TFT. Thus, an active matrix light-emitting device in which driving of the light-emitting element is controlled by the TFT can be manufactured. Note that the structure of the TFT is not particularly limited. A staggered TFT or an inverted staggered TFT may be used. Further, there is no particular limitation on the crystallinity of the semiconductor used for the TFT, and an amorphous semiconductor or a crystalline semiconductor may be used. Also, the driving circuit formed on the TFT array substrate may be composed of N-type and P-type TFTs, or may be composed of only one of N-type and P-type.

  Since the quinoxaline derivative of the present invention is a bipolar material and a light-emitting material, it can be used as a light-emitting layer without containing other light-emitting substances as shown in this embodiment mode. is there.

  In addition, because it is bipolar, the light emitting region is not easily biased at the interface of the stacked films, and a light emitting element having favorable characteristics with little change in the emission spectrum due to interactions such as exciplex and a decrease in light emission efficiency is manufactured. it can.

  Further, the microcrystalline component contained during film formation is very small, and the film formed has a small amount of microcrystalline component, and an amorphous film can be obtained. That is, since the film quality is good, a favorable light-emitting element with few element defects such as dielectric breakdown due to electric field concentration can be manufactured.

  Further, since the quinoxaline derivative of the present invention is bipolar and has excellent carrier transport properties (electron transport properties and hole transport properties), the use of the quinoxaline derivative for a light-emitting device reduces the driving voltage of the light-emitting device. This leads to a reduction in power consumption.

  In addition, since the quinoxaline derivative of the present invention has a high glass transition point, a light-emitting element having excellent heat resistance can be obtained by using it for a light-emitting element.

  In addition, the quinoxaline derivative of the present invention is stable even when the oxidation reaction and the subsequent reduction reaction, the reduction reaction and the subsequent oxidation reaction are repeated. That is, it is electrochemically stable. Therefore, a long-life light-emitting element can be obtained by using the quinoxaline derivative of the present invention for a light-emitting element.

  The quinoxaline derivative of the present invention emits light in a short wavelength region from blue to blue green in a solution state, but also emits light in a short wavelength region in a solid state as in the solution state. This is explained as follows. In the quinoxaline derivative of the present invention, a biphenyl group having a twist is bonded to an amino group, not a planar condensed aromatic ring such as a naphthyl group or a fluorenyl group. Then, it is difficult to associate in the solid state due to the twist of the biphenyl skeleton, and it is considered that the emission color in the solid state and the emission color in the solution state almost coincide. That is, the quinoxaline derivative of the present invention is characterized in that the peak of the emission spectrum in the solution state and the peak of the emission spectrum in the solid state are not substantially changed. ), It is possible to obtain light having a short wavelength.

(Embodiment 3)
In this embodiment, a light-emitting element having a structure different from that described in Embodiment 2 will be described.

  When the third layer 105 described in Embodiment Mode 2 has a structure in which the quinoxaline derivative of the present invention is dispersed in another substance, light emission from the quinoxaline derivative of the present invention can be obtained. Since the quinoxaline derivative of the present invention emits blue to blue-green light, a light-emitting element that emits blue to blue-green can be obtained.

  Here, various materials can be used as the material for dispersing the quinoxaline derivative of the present invention. In addition to the material having a high hole transport and the material having a high electron transport property described in Embodiment 2, 4, 4 '-Di (N-carbazolyl) -biphenyl (abbreviation: CBP) and 2,2', 2 "-(1,3,5-benzenetri-yl) -tris [1-phenyl-1H-benzimidazole] ( Abbreviations: TPBI), 9,10-di (2-naphthyl) anthracene (abbreviation: DNA), 2-tert-butyl-9,10-di (2-naphthyl) anthracene (abbreviation: t-BuDNA), and the like. .

  Since the quinoxaline derivative of the present invention is bipolar and has excellent carrier transport properties (electron transport properties and hole transport properties), the use of the quinoxaline derivative for a light-emitting device can reduce the driving voltage of the light-emitting device. This leads to a reduction in power consumption.

  In addition, since the quinoxaline derivative of the present invention has a high glass transition point, a light-emitting element having excellent heat resistance can be obtained by using it for a light-emitting element.

  In addition, the quinoxaline derivative of the present invention is stable even when the oxidation reaction and the subsequent reduction reaction, the reduction reaction and the subsequent oxidation reaction are repeated. That is, it is electrochemically stable. Therefore, a long-life light-emitting element can be obtained by using the quinoxaline derivative of the present invention for a light-emitting element.

  Note that the structure described in Embodiment 2 can be used as appropriate, except for the third layer 105.

(Embodiment 4)
In this embodiment, a light-emitting element having a structure different from those described in Embodiment 2 and Embodiment 3 will be described.

  When the third layer 105 described in Embodiment Mode 2 has a structure in which a light-emitting substance is dispersed in the quinoxaline derivative of the present invention, light emission from the light-emitting substance can be obtained.

  The quinoxaline derivative of the present invention has a bipolar property and has a very small amount of microcrystalline components contained in the film formation and good film quality. Therefore, it can be suitably used as a material for dispersing other light-emitting substances.

  When the quinoxaline derivative of the present invention is used as a material for dispersing other light-emitting substances, a light emission color resulting from the light-emitting substance can be obtained. It is also possible to obtain a mixed emission color of the emission color caused by the quinoxaline derivative of the present invention and the emission color caused by the luminescent substance dispersed in the quinoxaline derivative.

Here, various materials can be used as the light-emitting substance dispersed in the quinoxaline derivative of the present invention, and specifically, 4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl). ) -4H-pyran (abbreviation: DCM1), 4- (dicyanomethylene) -2-methyl-6- (julolidin-4-yl-vinyl) -4H-pyran (abbreviation: DCM2), N, N′-dimethylquinacridone (Abbreviation: DMQd), 9,10-diphenylanthracene (abbreviation: DPA), 5,12-diphenyltetracene (abbreviation: DPT), coumarin 6, perylene, rubrene, and other fluorescent materials, bis [2- ( Phosphorescence of 2′-benzothienyl) pyridinato-N, C ^{3 ′} ] (acetylacetonato) iridium (abbreviation: Ir (btp) ₂ (acac)) A light substance can also be used.

  Further, as the light-emitting substance dispersed in the quinoxaline derivative of the present invention, an organometallic complex including a structure represented by the following general formula (101) can be used.

(Wherein R ^{1 to} R ⁵ each represent hydrogen, a halogen element, an acyl group, an alkyl group, an alkoxyl group, an aryl group, a cyano group, or a heterocyclic group. Ar represents an aryl group or a heterocyclic group. M represents a Group 9 element or a Group 10 element.)

  In General Formula (101), Ar is preferably an aryl group having an electron-withdrawing substituent or a heterocyclic group having an electron-withdrawing substituent. When Ar is a group having an electron-withdrawing substituent, an organometallic complex that emits phosphorescence with higher emission intensity can be obtained.

  In particular, an organometallic complex having a structure represented by the following general formula (102) is preferable.

(In the formula, R ¹¹ represents any of an alkyl group having 1 to 4 carbon atoms. R ^{12 to} R ¹⁵ are each a hydrogen atom, a halogen element, an acyl group, an alkyl group, an alkoxyl group, an aryl group, or a cyano group. R ^{16 to} R ¹⁹ each represent hydrogen, an acyl group, an alkyl group, an alkoxyl group, an aryl group, a heterocyclic group, or an electron-withdrawing substituent. M represents a Group 9 element or a Group 10 element.)

In General Formula (102), at least one of R ^{16 to} R ¹⁹ is preferably an electron-withdrawing substituent. As a result, an organometallic complex that emits phosphorescence with higher emission intensity can be obtained.

  In particular, an organometallic complex having a structure represented by the following general formula (103) is preferable.

(In the formula, R ^{22 to} R ³⁴ each represent hydrogen, a halogen element, an acyl group, an alkyl group, an alkoxyl group, an aryl group, a cyano group, a heterocyclic group, or an electron-withdrawing substituent. Represents a Group 9 element or a Group 10 element.)

In general formula (103), it is preferable that at least one of R ^{26 to} R ²⁹ is an electron-withdrawing substituent. As a result, an organometallic complex that emits phosphorescence with higher emission intensity can be obtained.

  Examples of the organometallic complex having the structure represented by the general formula (101) include an organometallic complex represented by the general formula (104).

(Wherein R ^{1 to} R ⁵ each represent hydrogen, a halogen element, an acyl group, an alkyl group, an alkoxyl group, an aryl group, a cyano group, or a heterocyclic group. Ar represents an aryl group or a heterocyclic group. M represents a Group 9 element or a Group 10 element, n = 2 when M is a Group 9 element, and n = 1 when M is a Group 10 element L is a beta diketone It represents either a monoanionic ligand having a structure, a monoanionic bidentate chelate ligand having a carboxyl group, or a monoanionic bidentate chelate ligand having a phenolic hydroxyl group. )

  In General Formula (104), Ar is preferably an aryl group having an electron-withdrawing substituent or a heterocyclic group having an electron-withdrawing substituent. When Ar is a group having an electron-withdrawing substituent, an organometallic complex that emits phosphorescence with higher emission intensity can be obtained.

  In particular, an organometallic complex represented by the general formula (105) is preferable.

(In the formula, R ¹¹ represents any of an alkyl group having 1 to 4 carbon atoms. R ^{12 to} R ¹⁵ are each a hydrogen atom, a halogen element, an acyl group, an alkyl group, an alkoxyl group, an aryl group, or a cyano group. R ^{16 to} R ¹⁹ each represent hydrogen, an acyl group, an alkyl group, an alkoxyl group, an aryl group, a heterocyclic group, or an electron-withdrawing substituent. M represents a Group 9 or Group 10 element, n = 2 when M is a Group 9 element, and n = 1 when M is a Group 10. L is a beta diketone. It represents either a monoanionic ligand having a structure, a monoanionic bidentate chelate ligand having a carboxyl group, or a monoanionic bidentate chelate ligand having a phenolic hydroxyl group. )

In general formula (105), it is preferable that at least one of R ^{16 to} R ¹⁹ is an electron-withdrawing substituent. As a result, an organometallic complex that emits phosphorescence with higher emission intensity can be obtained.

  In particular, an organometallic complex represented by the general formula (106) is preferable.

(In the formula, R ^{22 to} R ³⁴ each represent hydrogen, a halogen element, an acyl group, an alkyl group, an alkoxyl group, an aryl group, a cyano group, a heterocyclic group, or an electron-withdrawing substituent. Represents a Group 9 element or a Group 10 element, n = 2 when M is a Group 9 element and n = 1 when M is a Group 10 element L is a monoanion having a beta diketone structure Or a monoanionic bidentate chelate ligand having a carboxyl group, or a monoanionic bidentate chelate ligand having a phenolic hydroxyl group.)

In General Formula (106), at least one of R ^{26 to} R ²⁹ is preferably an electron-withdrawing substituent. As a result, an organometallic complex that emits phosphorescence with higher emission intensity can be obtained.

  In the organometallic complex including the structure represented by the general formulas (101) to (103) and the organometallic complex represented by the general formulas (104) to (106), the electron-withdrawing substituent is a halogen group or a haloalkyl. It is preferably either a group or a cyano group. Thereby, the chromaticity and quantum efficiency of the organometallic complex are improved. Further, among the halogen groups, a fluoro group is particularly preferable, and among the haloalkyl groups, a trifluoromethyl group is particularly preferable. This also improves the efficiency of trapping electrons.

  In the organometallic complexes including the structures represented by the general formulas (101) to (103) and the organometallic complexes represented by the general formulas (104) to (106), the central metal M is preferably a heavy metal, and particularly iridium. Or it is preferable that it is platinum. Thereby, the heavy atom effect can be obtained.

  In the general formulas (104) to (106), the ligand L is a monoanionic ligand having a beta diketone structure, a monoanionic bidentate chelate ligand having a carboxyl group, or Any monoanionic bidentate chelate ligand having a phenolic hydroxyl group may be used, but any of the monoanionic ligands represented by the following structural formulas (107) to (113) is preferable. These monoanionic chelate ligands are effective because they have high coordination ability and can be obtained at low cost.

  Specific examples of the organometallic complexes represented by the general formulas (101) to (106) include organometallic complexes represented by the structural formulas (114) to (126).

Note that a light-emitting element which emits light from a triplet excited state by adding the above phosphorescent substance which is an organometallic complex to the quinoxaline derivative of the present invention has low driving voltage and high current efficiency. Accordingly, a light-emitting element with low power consumption can be obtained.

  Since the quinoxaline derivative of the present invention is a bipolar material and has excellent carrier transport properties (electron transport property and hole transport property), the use of the quinoxaline derivative of the present invention reduces the driving voltage of the light-emitting element. can do.

  In addition, since the quinoxaline derivative of the present invention has a high glass transition point, a light-emitting element having excellent heat resistance can be obtained by using it for a light-emitting element.

  In addition, the quinoxaline derivative of the present invention is stable even when the oxidation reaction and the subsequent reduction reaction, the reduction reaction and the subsequent oxidation reaction are repeated. That is, it is electrochemically stable. Therefore, a long-life light-emitting element can be obtained by using the quinoxaline derivative of the present invention for a light-emitting element.

  In particular, by applying a light-emitting layer in which the specific organometallic complex represented by the general formula (101) described above is dispersed in the quinoxaline derivative of the present invention, a light-emitting element with significantly low power consumption and a long lifetime is obtained. be able to.

  The quinoxaline derivative of the present invention emits light in a short wavelength region from blue to blue green in a solution state, but also emits light in a short wavelength region in a solid state as in the solution state. This is explained as follows. In the quinoxaline derivative of the present invention, a biphenyl group having a twist is bonded to an amino group, not a planar condensed aromatic ring such as a naphthyl group or a fluorenyl group. Then, it is difficult to associate in the solid state due to the twist of the biphenyl skeleton, and it is considered that the emission color in the solid state and the emission color in the solution state almost coincide. That is, the quinoxaline derivative of the present invention is characterized in that the peak of the emission spectrum in the solution state and the peak of the emission spectrum in the solid state are not substantially changed. ) In the light-emitting element, the choice of the light-emitting substance to be dispersed in the quinoxaline derivative of the present invention is expanded. Specifically, when a phosphorescent material is used as the light-emitting substance to be dispersed, the peak of the emission spectrum of the phosphorescent light-emitting substance is preferably 560 nm to 700 nm. In the case where a fluorescent substance is used, the peak of the emission spectrum is preferably 500 nm or more and 700 nm or less. More preferably, it is 500 nm or more and 600 nm or less.

  Note that the structure described in Embodiment 2 can be used as appropriate, except for the third layer 105.

(Embodiment 5)
In this embodiment mode, a mode in which the quinoxaline derivative of the present invention is used as an active layer of a vertical transistor (SIT) which is a kind of organic semiconductor element is illustrated.

  As shown in FIG. 7, the structure of the element is a structure in which a thin-film active layer 1202 containing the quinoxaline derivative of the present invention is sandwiched between a source electrode 1201 and a drain electrode 1203 and a gate electrode 1204 is embedded in the active layer 1202. Have. The gate electrode 1204 is electrically connected to means for applying a gate voltage, and the source electrode 1201 and the drain electrode 1203 are electrically connected to means for controlling the source-drain voltage. Yes.

  In such an element structure, when a voltage is applied between the source and the drain without applying a gate voltage, a current flows (becomes ON state). When a gate voltage is applied in this state, a depletion layer is generated around the gate electrode 1204 and no current flows (becomes an OFF state). With the above mechanism, the transistor operates as a transistor.

  In the vertical transistor, a material having both carrier transportability and good film quality is required for the active layer as in the light-emitting element, but the quinoxaline derivative of the present invention sufficiently satisfies the conditions and is useful.

(Embodiment 6)
In this embodiment mode, a light-emitting device manufactured using the quinoxaline derivative of the present invention will be described with reference to FIGS.

  3A is a top view illustrating the light-emitting device, and FIG. 3B is a cross-sectional view taken along lines A-A ′ and B-B ′ in FIG. 3A. Reference numeral 601 indicated by a dotted line denotes a driving circuit portion (source side driving circuit), 602 denotes a pixel portion, and 603 denotes a driving circuit portion (gate side driving circuit). Reference numeral 604 denotes a sealing substrate, reference numeral 605 denotes a sealing material, and the inside surrounded by the sealing material 605 is a space 607.

  Note that the routing wiring 608 is a wiring for transmitting a signal input to the source side driving circuit 601 and the gate side driving circuit 603, and a video signal, a clock signal, an FPC (flexible printed circuit) 609 serving as an external input terminal, Receives start signal, reset signal, etc. Although only the FPC is shown here, a printed wiring board (PWB) may be attached to the FPC. The light-emitting device in this specification includes not only a light-emitting device body but also a state in which an FPC or a PWB is attached thereto.

  Next, a cross-sectional structure will be described with reference to FIG. A driver circuit portion and a pixel portion are formed over the element substrate 610. Here, a source-side driver circuit 601 that is a driver circuit portion and one pixel in the pixel portion 602 are illustrated.

  Note that the source side driver circuit 601 is a CMOS circuit in which an n-channel TFT 623 and a p-channel TFT 624 are combined. The TFT forming the driving circuit may be formed by various CMOS circuits, PMOS circuits, or NMOS circuits. In this embodiment, a driver integrated type in which a drive circuit is formed on a substrate is shown. However, this is not always necessary, and the drive circuit can be formed outside the substrate. Further, there is no particular limitation on the crystallinity of the semiconductor used for the TFT, and an amorphous semiconductor or a crystalline semiconductor may be used.

  The pixel portion 602 is formed by a plurality of pixels including a switching TFT 611, a current control TFT 612, and a first electrode 613 electrically connected to the drain thereof. Note that an insulator 614 is formed so as to cover an end portion of the first electrode 613. Here, a positive photosensitive acrylic resin film is used.

  In order to improve the coverage, a curved surface having a curvature is formed at the upper end or the lower end of the insulator 614. For example, when positive photosensitive acrylic is used as a material for the insulator 614, it is preferable that only the upper end portion of the insulator 614 has a curved surface with a curvature radius (0.2 μm to 3 μm). As the insulator 614, either a negative type that becomes insoluble in an etchant by light irradiation or a positive type that becomes soluble in an etchant by light irradiation can be used.

  Over the first electrode 613, a layer 616 containing a light-emitting substance and a second electrode 617 are formed. Here, as a material used for the first electrode 613 functioning as an anode, a material having a high work function is preferably used. For example, an ITO film or an indium tin oxide film containing silicon, an indium oxide film containing 2 to 20 wt% zinc oxide, a titanium nitride film, a chromium film, a tungsten film, a Zn film, a Pt film, or the like In addition, a stack of a titanium nitride film and a film containing aluminum as a main component, a three-layer structure including a titanium nitride film, a film containing aluminum as a main component, and a titanium nitride film can be used. Note that with a stacked structure, resistance as a wiring is low, good ohmic contact can be obtained, and a function as an anode can be obtained.

  The layer 616 containing a light-emitting substance is formed by various methods such as an evaporation method using an evaporation mask, an inkjet method, and a spin coating method. The layer 616 containing a light-emitting substance contains the quinoxaline derivative of the present invention described in Embodiment Mode 1. In addition, the other material forming the layer 616 containing a light-emitting substance may be a low molecular material, a medium molecular material (including an oligomer or a dendrimer), or a high molecular material. In addition, as a material used for a layer containing a light-emitting substance, an organic compound is usually used in a single layer or a stacked layer. I will do it.

Further, as a material used for the second electrode 617 which is formed over the light-emitting substance-containing layer 616 and functions as a cathode, a material having a low work function (Al, Mg, Li, Ca, or an alloy or compound thereof such as MgAg, MgIn, AlLi, LiF, or is preferably used CaF _2, etc.). Note that in the case where light generated in the layer 616 containing a light-emitting substance passes through the second electrode 617, the second electrode 617 includes a thin metal film and a transparent conductive film (ITO, 2 to 20 wt. % Of indium oxide containing zinc oxide, indium tin oxide containing silicon, zinc oxide (ZnO), or the like is preferably used.

  Further, the sealing substrate 604 is bonded to the element substrate 610 with the sealant 605, whereby the light-emitting element 618 is provided in the space 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealant 605. Yes. Note that the space 607 is filled with a filler, and may be filled with a sealant 605 in addition to an inert gas (such as nitrogen or argon).

  Note that an epoxy-based resin is preferably used for the sealant 605. Moreover, it is desirable that these materials are materials that do not transmit moisture and oxygen as much as possible. In addition to a glass substrate or a quartz substrate, a plastic substrate made of FRP (Fiberglass-Reinforced Plastics), PVF (polyvinyl fluoride), Mylar, polyester, acrylic, or the like can be used as a material for the sealing substrate 604.

  As described above, a light-emitting device manufactured using the quinoxaline derivative of the present invention can be obtained.

  Since the quinoxaline derivative described in Embodiment Mode 1 is used for the light-emitting device of the present invention, a light-emitting device having favorable characteristics can be obtained. Specifically, a light-emitting device with high heat resistance can be obtained.

In addition, since the quinoxaline derivative of the present invention is electrochemically stable, a long-life light-emitting device can be obtained.

  In addition, since the quinoxaline derivative of the present invention is bipolar and is a material having excellent carrier transport properties (electron transport property and hole transport property), the use of the quinoxaline derivative of the present invention enables driving voltage of a light-emitting element. The power consumption of the light emitting device can be reduced. In particular, when a phosphorescent material is used as the light-emitting material, a light-emitting device with high light emission efficiency and lower power consumption can be obtained.

  As described above, in this embodiment mode, an active light-emitting device that controls driving of a light-emitting element using a transistor has been described. In addition to this, a light-emitting element is driven without particularly providing a driving element such as a transistor. A passive light emitting device may be used. FIG. 4 is a perspective view of a passive light emitting device manufactured by applying the present invention. In FIG. 4, a layer 955 containing a light-emitting substance is provided between the electrode 952 and the electrode 956 over the substrate 951. An end portion of the electrode 952 is covered with an insulating layer 953. A partition layer 954 is provided over the insulating layer 953. The side wall of the partition wall layer 954 has an inclination such that the distance between one side wall and the other side wall becomes narrower as it approaches the substrate surface. That is, the cross section in the short side direction of the partition wall layer 954 has a trapezoidal shape, and the bottom side (the side facing the insulating layer 953 in the same direction as the surface direction of the insulating layer 953) is the top side (the surface of the insulating layer 953). The direction is the same as the direction and is shorter than the side not in contact with the insulating layer 953. In this manner, by providing the partition layer 954, defects in the light-emitting element due to static electricity or the like can be prevented. A passive light emitting device can also be driven with low power consumption by including the light emitting element of the present invention that operates at a low driving voltage.

(Embodiment 7)
In this embodiment, an electronic device of the present invention including the light-emitting device described in Embodiment 4 as part thereof will be described. An electronic device of the present invention includes the quinoxaline derivative described in Embodiment 1 and has a display portion with high heat resistance. In addition, the display unit has a long life. In addition, a display portion with reduced power consumption is included.

  As an electronic device having a light-emitting element manufactured using the quinoxaline derivative of the present invention, a video camera, a digital camera, a goggle type display, a navigation system, a sound reproduction device (car audio, audio component, etc.), a computer, a game device, a mobile phone An information terminal (mobile computer, mobile phone, portable game machine, electronic book, etc.), an image playback device (specifically, Digital Versatile Disc (DVD)) provided with a recording medium, and the image is displayed. And a device provided with a display device capable of performing the above. Specific examples of these electronic devices are shown in FIGS.

  FIG. 5A illustrates a television device according to the present invention, which includes a housing 9101, a supporting base 9102, a display portion 9103, a speaker portion 9104, a video input terminal 9105, and the like. In this television device, the display portion 9103 is formed by arranging light-emitting elements similar to those described in Embodiments 2 to 4 in a matrix. The light-emitting element can be driven at a low voltage and has a long life. Moreover, it has the characteristic that heat resistance is high. Since the display portion 9103 including the light-emitting elements has similar features, this television set has little deterioration in image quality and low power consumption. With such a feature, the deterioration compensation function and the power supply circuit can be significantly reduced or reduced in the television device, so that the housing 9101 and the support base 9102 can be reduced in size and weight. In the television device according to the present invention, low power consumption, high image quality, and reduction in size and weight are achieved, so that a product suitable for a living environment can be provided.

  FIG. 5B illustrates a computer according to the present invention, which includes a main body 9201, a housing 9202, a display portion 9203, a keyboard 9204, an external connection port 9205, a pointing mouse 9206, and the like. In this computer, the display portion 9203 is formed by arranging light-emitting elements similar to those described in Embodiments 2 to 4 in a matrix. The light-emitting element can be driven at a low voltage and has a long life. Moreover, it has the characteristic that heat resistance is high. The display portion 9203 which includes the light-emitting elements has similar features. Therefore, in this computer, image quality is hardly deteriorated and low power consumption is achieved. With such a feature, the deterioration compensation function and the power supply circuit can be significantly reduced or reduced in the computer, so that the main body 9201 and the housing 9202 can be reduced in size and weight. In the computer according to the present invention, low power consumption, high image quality, and reduction in size and weight are achieved; therefore, a product suitable for the environment can be provided.

  FIG. 5C illustrates a cellular phone according to the present invention, which includes a main body 9401, a housing 9402, a display portion 9403, an audio input portion 9404, an audio output portion 9405, operation keys 9406, an external connection port 9407, an antenna 9408, and the like. . In this cellular phone, the display portion 9403 is formed by arranging light-emitting elements similar to those described in Embodiments 2 to 4 in a matrix. The light-emitting element can be driven at a low voltage and has a long life. Moreover, it has the characteristic that heat resistance is high. Since the display portion 9403 including the light-emitting elements has similar features, the cellular phone has little deterioration in image quality and low power consumption. With such a feature, the deterioration compensation function and the power supply circuit can be significantly reduced or reduced in the mobile phone, so that the main body 9401 and the housing 9402 can be reduced in size and weight. Since the cellular phone according to the present invention has low power consumption, high image quality, and reduced size and weight, a product suitable for carrying can be provided.

  FIG. 5D illustrates a camera according to the present invention, which includes a main body 9501, a display portion 9502, a housing 9503, an external connection port 9504, a remote control receiving portion 9505, an image receiving portion 9506, a battery 9507, an audio input portion 9508, and operation keys 9509. , An eyepiece 9510 and the like. In this camera, the display portion 9502 is configured by arranging light-emitting elements similar to those described in Embodiments 2 to 4 in a matrix. The light-emitting element can be driven at a low voltage and has a long life. Moreover, it has the characteristic that heat resistance is high. Since the display portion 9502 including the light-emitting elements has similar features, this camera has little deterioration in image quality and low power consumption. With such a feature, a deterioration compensation function and a power supply circuit can be significantly reduced or reduced in the camera, so that the main body 9501 can be reduced in size and weight. Since the camera according to the present invention has low power consumption, high image quality, and small size and light weight, a product suitable for carrying can be provided.

  As described above, the applicable range of the light-emitting device of the present invention is so wide that the light-emitting device can be applied to electronic devices in various fields. By using the quinoxaline derivative of the present invention, an electronic device having a display portion with low power consumption, a long lifetime, and high heat resistance can be provided.

  The light-emitting device of the present invention can also be used as a lighting device. One mode in which the light-emitting element of the present invention is used as a lighting device will be described with reference to FIGS.

  FIG. 6 illustrates an example of a liquid crystal display device using the light-emitting device of the present invention as a backlight. The liquid crystal display device illustrated in FIG. 6 includes a housing 901, a liquid crystal layer 902, a backlight 903, and a housing 904, and the liquid crystal layer 902 is connected to a driver IC 905. The backlight 903 uses the light-emitting device of the present invention, and a current is supplied from a terminal 906.

  By using the light emitting device of the present invention as a backlight of a liquid crystal display device, a backlight with reduced power consumption can be obtained. Further, the light-emitting device of the present invention is a surface-emitting illumination device and can have a large area, so that the backlight can have a large area and a liquid crystal display device can have a large area. Further, since the light-emitting device of the present invention is thin and has low power consumption, the display device can be thinned and the power consumption can be reduced. In addition, since the light-emitting device of the present invention has a long life and excellent heat resistance, the light-emitting device of the present invention also has a long life and excellent heat resistance.

  In this example, 2,3-bis {4- [N- (4-biphenylyl) -N-phenylamino] phenyl} quinoxaline (hereinafter referred to as the quinoxaline derivative of the present invention represented by the following structural formula (14)). A synthesis example of BPAPQ) will be specifically illustrated.

[Step 1]
A method for synthesizing 2,3-bis (4-bromophenyl) quinoxaline will be described. A synthesis scheme of 2,3-bis (4-bromophenyl) quinoxaline is shown in (B-1).

  Under a nitrogen atmosphere, a chloroform solution (200 mL) of 30.0 g (81.5 mmol) of 4,4′-dibromobenzyl and 9.00 g (83.2 mmol) of o-phenylenediamine was refluxed at 80 ° C. for 3 hours. After the reaction solution was cooled to room temperature, the reaction solution was washed with water. The obtained aqueous layer was extracted with chloroform, and the extracted solution was combined with the organic layer and washed with saturated brine. After drying the organic layer with magnesium sulfate, the mixture was suction filtered, and the filtrate was concentrated. As a result, 33 g of the desired 2,3-bis (4-bromophenyl) quinoxaline as a white solid was obtained in a yield of 92%. Obtained.

[Step 2]
A method for synthesizing N- (4-biphenylyl) -N-phenylamine will be described. A synthesis scheme of N- (4-biphenylyl) -N-phenylamine is shown in (B-2).

  Under nitrogen atmosphere, xylene suspension of 20.0 g (85.8 mmol) of 4-bromobiphenyl, 16.0 g (172 mmol) of aniline, 0.19 g (0.86 mmol) of palladium acetate, and 23.7 g (172 mmol) of potassium carbonate ( To 150 mL), 5.2 g (2.5 mmol) of tri-tert-butylphosphine (10% hexane solution) was added, and the mixture was refluxed at 120 ° C. for 10 hours. After completion of the reaction, the reaction mixture was washed with water, and the aqueous layer was extracted with toluene. The toluene layer and the organic layer were combined and washed with saturated brine, and the obtained organic layer was dried over magnesium sulfate. The mixture was suction filtered and the filtrate was concentrated. The obtained residue was purified by silica gel column chromatography (developing solvent: toluene). The obtained solution was concentrated to obtain 13.5 g of N- (4-biphenylyl) -N-phenylamine as a white solid in a yield of 64%.

[Step 3]
A method for synthesizing 2,3-bis {4- [N- (4-biphenylyl) -N-phenylamino] phenyl} quinoxaline (hereinafter referred to as BPAPQ) will be described. A synthesis scheme of BPAPQ is shown in (B-3).

  Under a nitrogen atmosphere, 2,3-bis (4-bromophenyl) quinoxaline 5.0 g (11.4 mmol), N- (4-biphenylyl) -N-phenylamine 6.1 g (25.0 mmol), bis (dibenzylidene) Acetone) Toluene suspension (80 mL) of palladium (0) 0.33 g (0.58 mmol) and tert-butoxy sodium 5.5 g (56.8 mmol) in tri-tert-butylphosphine (10% hexane solution) 2 g (0.58 mmol) was added and the mixture was heated at 80 ° C. for 7 hours. After completion of the reaction, the reaction mixture was cooled to room temperature, and the precipitate was collected by suction filtration. The obtained filtrate was dissolved in toluene, and this solution was suction filtered through Celite, Florisil, and alumina, and the filtrate was concentrated. When the obtained residue was recrystallized with chloroform and hexane, 8.1 g of BPAPQ was obtained as a yellow powdery solid in a yield of 78%.

Analysis results of BPAPQ by proton nuclear magnetic resonance spectroscopy ( ¹ H NMR) were as follows. ¹ H NMR (300 MHz, CDCl ₃ ); δ = 8.16-8.13 (m, 2H), 7.75-7.72 (m, 2H), 7.58-7.04 (m, 36H) . FIG. 8A shows an NMR chart of BPAPQ, and FIG. 8B shows an enlarged NMR chart of a portion of 6 to 9 ppm.

  When the decomposition temperature (Td) of BPAPQ was measured with a differential thermothermal gravimetric simultaneous measurement device (Seiko Denshi Co., Ltd., TG / DTA320 type), it was found that Td = 436 ° C. and good heat resistance was exhibited.

  Moreover, the glass transition point was measured using the differential scanning calorimeter (DSC, the Perkin Elmer company make, Pyris1). First, the sample was heated to 300 ° C. at 40 ° C./min to melt the sample, and then cooled to room temperature at 40 ° C./min. Thereafter, the DSC chart of FIG. 15 was obtained by raising the temperature to 300 ° C. at 10 ° C./min. From this chart, it was found that BPAPQ had a glass transition point (Tg) of 114 ° C. and a melting point of 268 ° C. From this, it was found that BPAPQ has a high glass transition point.

  FIG. 9 shows an absorption spectrum of a toluene solution of BPAPQ, and FIG. 10 shows an absorption spectrum of a thin film. It was found that the toluene solution had peaks at 325 and 402 nm, and the thin film had peaks at 328 and 418 nm.

  FIG. 11 shows an emission spectrum and an excitation spectrum of a BPAPQ toluene solution. It was found that the emission maximum was 483 nm in the toluene solution. In addition, FIG. 12 shows an emission spectrum of a BPAPQ thin film (solid state) excited by ultraviolet light having a wavelength of 365 nm. In FIG. 12, the emission maximum was shown at 499 nm in the solid state, and it was found that there was no significant difference in the emission maximum between the toluene solution and the solid state. That is, BPAPQ is derived from the twist of the biphenyl skeleton and hardly associates in the solid state, and can emit light having a short wavelength even in the solid state, similar to the luminescent color in the solution state.

  Moreover, it was -5.31 eV as a result of measuring the HOMO level in a thin film state by the photoelectron spectroscopy in the air (the Riken Keiki Co., Ltd. make, AC-2). Furthermore, when the optical energy gap was determined from the Tauc plot assuming direct transition using the absorption spectrum data of FIG. 10, the energy gap was 2.66 eV. Therefore, the LUMO level is −2.65 eV.

In addition, the electrochemical stability of BPAPQ was evaluated by cyclic voltammetry (CV). As the measuring apparatus, an electrochemical analyzer (manufactured by BAS Co., Ltd., model number: ALS model 600A) was used. The solution in CV measurement uses dehydrated dimethylformamide (DMF) as a solvent, and dissolves the supporting electrolyte tetra-n-butylammonium perchlorate (n-Bu ₄ NClO ₄ ) to a concentration of 100 mM. It was prepared by dissolving BPAPQ to be measured to a concentration of 1 mM. In addition, as a working electrode, a platinum electrode (manufactured by BAS Co., Ltd., PTE platinum electrode), and as an auxiliary electrode, a platinum electrode (manufactured by BAS Inc., Pt counter electrode for VC-3 ( 5 cm)), and an Ag / Ag ⁺ electrode (manufactured by BAS Co., Ltd., RE5 nonaqueous solvent system reference electrode) was used as a reference electrode. The scan rate was 0.1 V / sec, and 100 cycles of CV measurement were performed on each of the oxidation side and the reduction side.

  FIG. 13 shows the CV measurement result on the oxidation side of BPAPQ, and FIG. 14 shows the CV measurement result on the reduction side of BPAPQ. It was found that both the oxidation side and the reduction side give reversible peaks. It was also found that the cyclic voltammogram hardly changed even after 100 times of oxidation or reduction. This means that BPAPQ is stable against oxidation and reduction. In other words, it means that it is electrochemically stable.

  In this example, 2,3-bis {4- [N, N-di (4-biphenylyl) amino] phenyl} quinoxaline (hereinafter referred to as BBAPQ) which is a quinoxaline derivative of the present invention represented by the following structural formula (39). The synthesis example is described specifically.

[Step 1]
A method for synthesizing N, N-bis (4-bromophenyl) amine will be described. A synthesis scheme of N, N-bis (4-bromophenyl) amine is shown in (C-1).

  To an ethyl acetate solution (400 mL) of 10 g (59 mmol) of diphenylamine was added 22.1 g (124 mmol) of N-bromosuccinimide, and the mixture was stirred at room temperature for 16 hours. After completion of the reaction, the reaction mixture was washed with water, the aqueous layer was extracted with ethyl acetate, and the extracted solution was combined with the organic layer. The obtained organic layer was washed with saturated brine, and the organic layer was dried over magnesium sulfate. The mixture was suction filtered and the filtrate was concentrated. The obtained residue was washed with hexane, and the hexane suspension was subjected to suction filtration to collect a solid. As a result, 9.5 g of N, N-bis (4-bromophenyl) amine as a white solid was collected. Obtained at a rate of 49%.

[Step 2]
A method for synthesizing N, N-di (4-biphenylyl) amine will be described. A synthesis scheme of N, N-di (4-biphenylyl) amine is shown in (C-2).

  Under a nitrogen atmosphere, N, N-bis (4-bromophenyl) amine 9.5 g (29 mmol), phenylboronic acid 7.9 g (65 mmol), palladium acetate 0.15 g (0.646 mmol), tris (o-tolyl) To a solution of 1.4 g (4.5 mmol) of phosphine in ethylene glycol dimethyl ether (20 mL) was added 95 mL of an aqueous potassium carbonate solution (2.0 mol / L), and the solution was refluxed at 90 ° C. for 7 hours. After completion of the reaction, the reaction mixture was filtered, and the obtained solid was recrystallized from chloroform and hexane. As a result, 6.7 g yield of the target N, N-di (4-biphenylyl) amine as a white powdery solid was obtained. Obtained at 72%.

[Step 3]
A method for synthesizing 2,3-bis {4- [N, N-di (4-biphenylyl) amino] phenyl} quinoxaline (hereinafter referred to as BBAPQ) will be described. A synthesis scheme of BBAPQ is shown in (C-3).

  Under a nitrogen atmosphere, 3.0 g (8.1 mmol) of 2,3-bis (4-bromophenyl) quinoxaline synthesized in Step 1 of Example 1, 5.7 g (18 mmol) of N, N-di (4-biphenylyl) amine ), 0.22 g (0.41 mmol) of bis (dibenzylideneacetone) palladium (0), 3.9 g (41 mmol) of tert-butoxy sodium in a toluene suspension (80 mL), 0.082 g of tri-tert-butylphosphine ( 0.41 mmol) was added and the mixture was heated at 80 ° C. for 8 hours. After completion of the reaction, the reaction mixture was suction filtered, the resulting solid was dissolved in chloroform, and the solution was suction filtered through Celite, Florisil, and alumina. The filtrate was concentrated, and the resulting residue was recrystallized from chloroform and hexane to obtain 5.7 g of the target product BBAPQ as a yellow solid in a yield of 76%.

The analysis results of BBAPQ by proton nuclear magnetic resonance spectroscopy ( ¹ H NMR) were as follows. ¹ H NMR (300 MHz, CDCl ₃ ); δ = 8.18-8.15 (m, 2H), 7.76-7.73 (m, 2H), 7.58-7.16 (m, 44H) . FIG. 16A shows an NMR chart of BBAPQ, and FIG. 16B shows an enlarged NMR chart of a portion of 6 to 9 ppm.

  When the decomposition temperature (Td) of BBAPQ was measured with a differential thermothermal gravimetric simultaneous measurement device (Seiko Denshi Co., Ltd., TG / DTA320 type), it was found that Td = 486 ° C. and good heat resistance was exhibited.

  Moreover, the glass transition point was measured using the differential scanning calorimeter (DSC, the Perkin Elmer company make, Pyris1). First, the sample was heated to 380 ° C. at 40 ° C./min to melt the sample, and then cooled to −10 ° C. at 40 ° C./min. Thereafter, the DSC chart of FIG. 23 was obtained by raising the temperature to 380 ° C. at 10 ° C./min. From this chart, it was found that the glass transition point (Tg) of BBAPQ was 140 ° C. Note that the melting point is 321 ° C. from the DSC chart when the sample is first melted. From this, it was found that BBAPQ has a high glass transition point.

  An absorption spectrum of a toluene solution of BBAPQ is shown in FIG. The toluene solution was found to have peaks at 305 and 375 nm.

  Next, the electrochemical stability of BBAPQ was evaluated. The evaluation method is the same as the evaluation method of electrochemical stability of BPAPQ shown in Example 1.

  FIG. 21 shows the CV measurement result on the oxidation side of BBAPQ, and FIG. 22 shows the CV measurement result on the reduction side of BBAPQ. It was found that both the oxidation side and the reduction side give reversible peaks. It was also found that the cyclic voltammogram hardly changed even after 100 times of oxidation or reduction. This means that BBAPQ is stable against oxidation and reduction. In other words, it means that it is electrochemically stable.

  In this example, a light-emitting element of the present invention will be described with reference to FIG.

  First, indium tin oxide containing silicon oxide was formed over a glass substrate 2101 by a sputtering method, so that a first electrode 2102 was formed. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. After that, the inside of the vacuum apparatus was evacuated, and the pressure was reduced to about 10 ⁻⁴ Pa. Then, NPB and molybdenum oxide (VI) were co-evaporated on the first electrode 2102 to form a layer 2103 containing a composite material. . The film thickness was 50 nm, and the weight ratio of NPB and molybdenum oxide (VI) was adjusted to 4: 1 (= NPB: molybdenum oxide). Note that the co-evaporation method is an evaporation method in which evaporation is performed simultaneously from a plurality of evaporation sources in which different materials are held in one processing chamber.

  Next, NPB was formed to a thickness of 10 nm over the layer 2103 containing the composite material by an evaporation method using resistance heating, so that a hole-transport layer 2104 was formed.

Furthermore, 2,3-bis {4- [N- (4-biphenylyl) -N-phenylamino] phenyl} quinoxaline (hereinafter referred to as BPAPQ) which is the quinoxaline derivative of the present invention represented by the structural formula (14). (Acetylacetonato) bis [2,3-bis (4-fluorophenyl) quinoxalinato] iridium (III) represented by the structural formula (114) (hereinafter abbreviated as Ir (Fdpq) ₂ (acac)) Was co-evaporated to form a light-emitting layer 2105 having a thickness of 30 nm on the hole-transport layer 2104. Here, the weight ratio between BPAPQ and Ir _(Fdpq) 2 acac was 1: 0.1: was adjusted to _{(= BPAPQ Ir (Fdpq) 2} acac). As a result, Ir (Fdpq) ₂ acac is dispersed in the BPAPQ layer.

  Thereafter, Alq was deposited to a thickness of 10 nm on the light emitting layer 2105 by an evaporation method using resistance heating, whereby an electron transporting layer 2106 was formed.

  Further, Alq and lithium were co-evaporated on the electron transport layer 2106 to form an electron injection layer 2107 with a thickness of 50 nm on the Alq. Here, the weight ratio of Alq to lithium was adjusted to be 1: 0.01 (= Alq: lithium). As a result, lithium is dispersed in the Alq layer.

  Finally, the second electrode 2108 is formed by depositing aluminum on the electron injection layer 2107 so as to have a thickness of 200 nm using a resistance heating vapor deposition method, whereby the light-emitting element of Example 3 Was made.

FIG. 18 shows current density-luminance characteristics of the light-emitting element of Example 3. In addition, FIG. 19 shows luminance-voltage characteristics. FIG. 20 shows current efficiency-luminance characteristics. In addition, FIG. 33 shows an emission spectrum when a current of 1 mA is passed. In the light-emitting element of Example 3, the voltage necessary to obtain a luminance of 970 cd / m ² is 6.2 V, and the current that flows at that time is 1.40 mA (current density is 34.9 mA / cm ² ). The CIE chromaticity coordinates were (x = 0.66, y = 0.32). Moreover, the current efficiency at this time was 2.8 cd / A, and the power efficiency was 1.4 lm / W.

  As described above, a red light-emitting element with low power consumption can be obtained by combining the quinoxaline derivative of the present invention and an organometallic complex.

Further, a light-emitting element having a structure similar to that of the above light-emitting element was manufactured, and a continuous lighting test with a constant current drive was performed at an initial luminance of 1000 cd / m ^2. I knew it was keeping. Therefore, by using the quinoxaline derivative of the present invention, a long-life light-emitting element can be obtained.

  In this example, a light-emitting element of the present invention will be described with reference to FIG.

  First, indium tin oxide containing silicon oxide was formed over a glass substrate 2101 by a sputtering method, so that a first electrode 2102 was formed. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. After that, the inside of the vacuum apparatus was evacuated, and the pressure was reduced to about 10 ⁻⁴ Pa. Then, NPB and molybdenum oxide (VI) were co-evaporated on the first electrode 2102 to form a layer 2103 containing a composite material. . The film thickness was 50 nm, and the weight ratio of NPB and molybdenum oxide (VI) was adjusted to 4: 1 (= NPB: molybdenum oxide).

  Next, NPB was formed to a thickness of 10 nm over the layer 2103 containing the composite material by an evaporation method using resistance heating, so that a hole-transport layer 2104 was formed.

Furthermore, 2,3-bis {4- [N, N-di (4-biphenylyl) amino] phenyl} quinoxaline (hereinafter referred to as BBAPQ) which is the quinoxaline derivative of the present invention represented by the structural formula (39); (Acetylacetonato) bis [2,3-bis (4-fluorophenyl) quinoxalinato] iridium (III) (hereinafter abbreviated as Ir (Fdpq) ₂ (acac)) represented by the structural formula (114); Was co-evaporated to form a light emitting layer 2105 having a thickness of 30 nm on the hole transport layer 2104. Here, the weight ratio between BBAPQ and Ir _(Fdpq) 2 acac was 1: 0.1: was adjusted to _{(= BBAPQ Ir (Fdpq) 2} acac). Thereby, Ir (Fdpq) ₂ acac is dispersed in the layer made of BBAPQ.

  Thereafter, Alq was deposited to a thickness of 10 nm on the light emitting layer 2105 by an evaporation method using resistance heating, whereby an electron transporting layer 2106 was formed.

  Further, Alq and lithium were co-evaporated on the electron transport layer 2106 to form an electron injection layer 2107 with a thickness of 50 nm on the Alq. Here, the weight ratio of Alq to lithium was adjusted to be 1: 0.01 (= Alq: lithium). As a result, lithium is dispersed in the Alq layer.

  Finally, the second electrode 2108 is formed by depositing aluminum to a thickness of 200 nm on the electron injection layer 2107 using a resistance heating vapor deposition method, whereby the light-emitting element of Example 4 Was made.

FIG. 24 shows the current density-luminance characteristics of the light-emitting element of Example 4. In addition, FIG. 25 shows luminance-voltage characteristics. In addition, FIG. 26 shows current efficiency-luminance characteristics. In addition, FIG. 34 shows an emission spectrum when a current of 1 mA is passed. In the light-emitting element of Example 4, the voltage necessary to obtain a luminance of 900 cd / m ² is 6.4 V, and the current flowing at that time is 1.39 mA (current density is 34.8 mA / cm ² ). The CIE chromaticity coordinates were (x = 0.65, y = 0.33). Moreover, the current efficiency at this time was 2.6 cd / A, and the power efficiency was 1.3 lm / W.

  As described above, a red light-emitting element with low power consumption can be obtained by combining the quinoxaline derivative of the present invention and an organometallic complex.

  In this example, a light-emitting element of the present invention will be described with reference to FIG.

  First, indium tin oxide containing silicon oxide was formed over a glass substrate 2101 by a sputtering method, so that a first electrode 2102 was formed. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. After that, the inside of the vacuum apparatus was evacuated, and the pressure was reduced to about 10 ⁻⁴ Pa, and then a layer 2103 containing a composite material was formed by co-evaporating DNTPD and molybdenum oxide (VI) on the first electrode 2102. . The film thickness was 50 nm, and the weight ratio of DNTPD and molybdenum oxide (VI) was adjusted to 4: 2 (= DNTPD: molybdenum oxide).

  Next, NPB was formed to a thickness of 10 nm over the layer 2103 containing the composite material by an evaporation method using resistance heating, so that a hole-transport layer 2104 was formed.

Furthermore, 2,3-bis {4- [N- (4-biphenylyl) -N-phenylamino] phenyl} quinoxaline (hereinafter referred to as BPAPQ) which is the quinoxaline derivative of the present invention represented by the structural formula (14). (Acetylacetonato) bis [2,3-bis (4-fluorophenyl) quinoxalinato] iridium (III) represented by the structural formula (114) (hereinafter abbreviated as Ir (Fdpq) ₂ (acac)) Was co-evaporated to form a light-emitting layer 2105 having a thickness of 30 nm on the hole-transport layer 2104. Here, the weight ratio between BPAPQ and Ir _(Fdpq) 2 acac was 1: 0.1: was adjusted to _{(= BPAPQ Ir (Fdpq) 2} acac). As a result, Ir (Fdpq) ₂ acac is dispersed in the BPAPQ layer.

  Thereafter, Alq is deposited to a thickness of 10 nm on the light-emitting layer 2105 by vapor deposition using resistance heating, and BPhen is deposited to a thickness of 50 nm to form an electron transport layer 2106. Formed.

  Further, an electron injection layer 2107 was formed on the electron transport layer 2106 by depositing lithium fluoride to a thickness of 1 nm.

  Finally, the second electrode 2108 is formed by depositing aluminum on the electron injection layer 2107 to have a thickness of 200 nm using a resistance heating vapor deposition method, whereby the light-emitting element of Example 5 Was made.

FIG. 27 shows current density-luminance characteristics of the light-emitting element of Example 5. In addition, FIG. 28 shows luminance-voltage characteristics. FIG. 29 shows current efficiency-luminance characteristics. In addition, FIG. 35 shows an emission spectrum when a current of 1 mA is passed. In the light-emitting element of Example 5, the voltage necessary to obtain a luminance of 1100 cd / m ² is 6.8 V, and the current flowing at that time is 0.99 mA (current density is 24.8 mA / cm ² ). The CIE chromaticity coordinates were (x = 0.68, y = 0.31). Moreover, the current efficiency at this time was 4.5 cd / A, and the power efficiency was 2.1 lm / W.

  As described above, a red light-emitting element with low power consumption can be obtained by combining the quinoxaline derivative of the present invention and an organometallic complex.

  In this example, a light-emitting element of the present invention will be described with reference to FIG.

  First, indium tin oxide containing silicon oxide was formed over a glass substrate 2101 by a sputtering method, so that a first electrode 2102 was formed. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. After that, the inside of the vacuum apparatus is evacuated, and the pressure is reduced to about 10 ⁻⁴ Pa. Then, t-BuDNA and molybdenum oxide (VI) are co-evaporated on the first electrode 2102, thereby forming a layer 2103 containing a composite material. Formed. The film thickness was 50 nm, and the ratio of t-BuDNA to molybdenum oxide (VI) was adjusted to 4: 1 (= t-BuDNA: molybdenum oxide) by weight.

  Next, NPB was formed to a thickness of 10 nm over the layer 2103 containing the composite material by an evaporation method using resistance heating, so that a hole-transport layer 2104 was formed.

Furthermore, 2,3-bis {4- [N- (4-biphenylyl) -N-phenylamino] phenyl} quinoxaline (hereinafter referred to as BPAPQ) which is the quinoxaline derivative of the present invention represented by the structural formula (14). (Acetylacetonato) bis [2,3-bis (4-fluorophenyl) quinoxalinato] iridium (III) (hereinafter abbreviated as Ir (Fdpq) ₂ (acac)) represented by the structural formula (114) Was co-evaporated to form a light emitting layer 2105 having a thickness of 30 nm on the hole transport layer 2104. Here, the weight ratio between BPAPQ and Ir _(Fdpq) 2 acac was 1: 0.1: was adjusted to _{(= BPAPQ Ir (Fdpq) 2} acac). As a result, Ir (Fdpq) ₂ acac is dispersed in the BPAPQ layer.

  Thereafter, Alq was deposited to a thickness of 10 nm on the light emitting layer 2105 by an evaporation method using resistance heating, whereby an electron transporting layer 2106 was formed.

  Further, Alq and lithium were co-evaporated on the electron transport layer 2106 to form an electron injection layer 2107 with a thickness of 50 nm on the Alq. Here, the weight ratio of Alq to lithium was adjusted to be 1: 0.01 (= Alq: lithium). As a result, lithium is dispersed in the Alq layer.

  Finally, a second electrode 2108 is formed by depositing aluminum with a thickness of 200 nm on the electron injection layer 2107 using a resistance heating vapor deposition method, whereby the light-emitting element of Example 6 Was made.

FIG. 30 shows the current density-luminance characteristics of the light-emitting element of Example 6. Further, FIG. 31 shows luminance-voltage characteristics. Further, FIG. 32 shows current efficiency-luminance characteristics. In addition, FIG. 36 shows an emission spectrum when a current of 1 mA is passed. In the light-emitting element of Example 6, the voltage necessary to obtain a luminance of 1000 cd / m ² is 5.4 V, and the current that flows is 1.36 mA (current density is 33.9 mA / cm ² ). The CIE chromaticity coordinates were (x = 0.65, y = 0.33). At this time, the current efficiency was 3.0 cd / A, and the power efficiency was 1.7 lm / W.

  As described above, a red light-emitting element with low power consumption can be obtained by combining the quinoxaline derivative of the present invention and an organometallic complex.

Further, regarding the light-emitting element of Example 6, when the continuous lighting test was performed with constant current driving at an initial luminance of 1000 cd / m ² , it was found that 70% of the initial luminance was maintained even after 2500 hours. It was. Therefore, by using the quinoxaline derivative of the present invention, a long-life light-emitting element can be obtained.

  In this example, a light-emitting element of the present invention will be described with reference to FIG.

  First, indium tin oxide containing silicon oxide was formed over a glass substrate 2101 by a sputtering method, so that a first electrode 2102 was formed. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

Next, the substrate on which the first electrode was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode was formed was downward. After that, the inside of the vacuum apparatus was evacuated, and the pressure was reduced to about 10 ⁻⁴ Pa. Then, NPB and molybdenum oxide (VI) were co-evaporated on the first electrode 2102 to form a layer 2103 containing a composite material. . The film thickness was 50 nm, and the weight ratio of NPB and molybdenum oxide (VI) was adjusted to 4: 1 (= NPB: molybdenum oxide).

  Next, NPB was formed to a thickness of 10 nm over the layer 2103 containing the composite material by an evaporation method using resistance heating, so that a hole-transport layer 2104 was formed.

Furthermore, 2,3-bis {4- [N- (4-biphenylyl) -N-phenylamino] phenyl} quinoxaline (hereinafter referred to as BPAPQ) which is the quinoxaline derivative of the present invention represented by the structural formula (14). And (acetylacetonato) bis [2- (4-fluorophenyl) -3-methylquinoxalinato] iridium (III) (hereinafter abbreviated as Ir (MFpq) ₂ (acac)) represented by the structural formula (123) The light emitting layer 2105 having a thickness of 30 nm was formed on the hole transport layer 2104. Here, the weight ratio between BPAPQ and Ir _(MFpq) 2 acac was 1: 0.01: was adjusted to _{(= BPAPQ Ir (MFpq) 2} acac). As a result, Ir (MFpq) ₂ acac is dispersed in the BPAPQ layer.

  Thereafter, BAlq was formed to a thickness of 10 nm on the light-emitting layer 2105 by an evaporation method using resistance heating to form an electron transport layer 2106.

  Further, Alq and lithium were co-evaporated on the electron transport layer 2106 to form an electron injection layer 2107 with a thickness of 50 nm on the Alq. Here, the weight ratio of Alq to lithium was adjusted to be 1: 0.01 (= Alq: lithium). As a result, lithium is dispersed in the Alq layer.

  Finally, a second electrode 2108 is formed by depositing aluminum with a thickness of 200 nm on the electron injection layer 2107 using a resistance heating vapor deposition method, whereby the light-emitting element of Example 6 Was made.

FIG. 38 shows current density-luminance characteristics of the light-emitting element of Example 7. Further, FIG. 39 shows luminance-voltage characteristics. Further, FIG. 40 shows current efficiency-luminance characteristics. In addition, FIG. 41 shows an emission spectrum when a current of 1 mA is passed. In the light-emitting element of Example 7, the voltage necessary to obtain a luminance of 1000 cd / m ² is 5.6 V, and the current flowing at that time is 0.43 mA (current density is 10.8 mA / cm ² ). The CIE chromaticity coordinates were (x = 0.69, y = 0.31). At this time, the current efficiency was 9.1 cd / A, and the power efficiency was 5.11 m / W.

Further, regarding the light-emitting element of Example 7, a continuous lighting test by constant current driving was performed at an initial luminance of 1000 cd / m ^2. As a result, 90% of the initial luminance was maintained even after 310 hours, and a long lifetime was achieved. It was found to be a light emitting element. That is, by applying the present invention, a long-life light-emitting element could be obtained.

  In addition, by combining the quinoxaline derivative of the present invention with an organometallic complex, a red light-emitting element with low power consumption can be obtained.

  In addition, the light emitting element of this example has high luminous efficiency. Therefore, a light-emitting element with reduced power consumption can be obtained.

4A and 4B illustrate a light-emitting element of the present invention. 4A and 4B illustrate a light-emitting element of the present invention. 4A and 4B illustrate a light-emitting device of the present invention. 4A and 4B illustrate a light-emitting device of the present invention. 8A and 8B each illustrate an electronic device of the invention. 8A and 8B each illustrate an electronic device of the invention. Sectional drawing explaining the organic-semiconductor element of this invention. FIG. 3 shows a ¹ H NMR chart of 2,3-bis {4- [N- (4-biphenylyl) -N-phenylamino] phenyl} quinoxaline which is a quinoxaline derivative of the present invention. The figure which shows the absorption spectrum in the toluene solution of 2,3-bis {4- [N- (4-biphenylyl) -N-phenylamino] phenyl} quinoxaline which is the quinoxaline derivative of this invention. FIG. 6 shows an absorption spectrum of a thin film of 2,3-bis {4- [N- (4-biphenylyl) -N-phenylamino] phenyl} quinoxaline which is a quinoxaline derivative of the present invention. The figure which shows the excitation spectrum and emission spectrum in the toluene solution of 2,3-bis {4- [N- (4-biphenylyl) -N-phenylamino] phenyl} quinoxaline which is the quinoxaline derivative of this invention. FIG. 9 shows an emission spectrum of a thin film of 2,3-bis {4- [N- (4-biphenylyl) -N-phenylamino] phenyl} quinoxaline which is a quinoxaline derivative of the present invention. The figure which shows the CV measurement result of the oxidation side of 2,3-bis {4- [N- (4-biphenylyl) -N-phenylamino] phenyl} quinoxaline which is a quinoxaline derivative of the present invention. The figure which shows the CV measurement result of the reducing side of 2,3-bis {4- [N- (4-biphenylyl) -N-phenylamino] phenyl} quinoxaline which is the quinoxaline derivative of the present invention. The figure which shows the DSC chart of 2,3-bis {4- [N- (4-biphenylyl) -N-phenylamino] phenyl} quinoxaline which is the quinoxaline derivative of the present invention. FIG. 3 shows a ¹ H NMR chart of 2,3-bis {4- [N, N-di (4-biphenylyl) amino] phenyl} quinoxaline which is a quinoxaline derivative of the present invention. The figure which shows the absorption spectrum in the toluene solution of 2,3-bis {4- [N, N-di (4-biphenylyl) amino] phenyl} quinoxaline which is the quinoxaline derivative of the present invention. FIG. 6 shows current density-luminance characteristics of the light-emitting element of Example 3. FIG. 10 shows voltage-luminance characteristics of the light-emitting element of Example 3. FIG. 10 shows luminance-current efficiency characteristics of the light-emitting element of Example 3. The figure which shows the CV measurement result of the oxidation side of 2,3-bis {4- [N, N-di (4-biphenylyl) amino] phenyl} quinoxaline which is the quinoxaline derivative of the present invention. The figure which shows the CV measurement result by the side of the reduction | restoration of 2,3-bis {4- [N, N-di (4-biphenylyl) amino] phenyl} quinoxaline which is the quinoxaline derivative of this invention. The figure which shows the DSC chart of 2,3-bis {4- [N, N-di (4-biphenylyl) amino] phenyl} quinoxaline which is the quinoxaline derivative of the present invention. FIG. 11 shows current density-luminance characteristics of the light-emitting element of Example 4; FIG. 10 shows voltage-luminance characteristics of the light-emitting element of Example 4. FIG. 10 shows luminance-current efficiency characteristics of the light-emitting element of Example 4; FIG. 10 shows current density-luminance characteristics of the light-emitting element of Example 5. FIG. 10 shows voltage-luminance characteristics of the light-emitting element of Example 5. FIG. 10 shows luminance-current efficiency characteristics of the light-emitting element of Example 5. FIG. 10 shows current density-luminance characteristics of the light-emitting element of Example 6; FIG. 16 shows voltage-luminance characteristics of the light-emitting element of Example 6. FIG. 10 shows luminance-current efficiency characteristics of the light-emitting element of Example 6; FIG. 6 shows an emission spectrum of the light-emitting element of Example 3. FIG. 6 shows an emission spectrum of the light-emitting element of Example 4. FIG. 10 shows an emission spectrum of the light-emitting element of Example 5. FIG. 10 shows an emission spectrum of the light-emitting element of Example 6. 4A and 4B illustrate a light-emitting element of the present invention. FIG. 13 shows current density-luminance characteristics of the light-emitting element of Example 7. FIG. 13 shows voltage-luminance characteristics of the light-emitting element of Example 7. FIG. 11 shows luminance-current efficiency characteristics of the light-emitting element of Example 7. FIG. 10 shows an emission spectrum of the light-emitting element of Example 7.

Explanation of symbols

101 Substrate 102 1st electrode 103 1st layer 104 2nd layer 105 3rd layer 106 4th layer 107 2nd electrode 302 1st electrode 303 1st layer 304 2nd layer 305 3rd Layer 306 fourth layer 307 second electrode 601 source side driving circuit 602 pixel portion 603 gate side driving circuit 604 sealing substrate 605 sealing material 607 space 608 wiring 609 FPC (flexible printed circuit)
610 Element substrate 611 TFT for switching
612 Current control TFT
613 First electrode 614 Insulator 616 Layer containing light emitting substance 617 Second electrode 618 Light emitting element 623 n-channel TFT
624 p-channel TFT
901 Case 902 Liquid crystal layer 903 Backlight 904 Case 905 Driver IC
906 Terminal 951 Substrate 952 Electrode 953 Insulating layer 954 Partition layer 955 Layer containing light emitting material 956 Electrode 1201 Source electrode 1202 Active layer 1203 Drain electrode 1204 Gate electrode 2101 Substrate 2102 First electrode 2103 Layer 2104 containing composite material Hole transport layer 2105 Light emitting layer 2106 Electron transport layer 2107 Electron injection layer 2108 Second electrode 9101 Case 9102 Support base 9103 Display portion 9104 Speaker portion 9105 Video input terminal 9201 Main body 9202 Case 9203 Display portion 9204 Keyboard 9205 External connection port 9206 Pointing mouse 9401 Main body 9402 Housing 9403 Display unit 9404 Audio input unit 9405 Audio output unit 9406 Operation key 9407 External connection port 9408 Antenna 9501 Main unit 9502 Display unit 9 503 Housing 9504 External connection port 9505 Remote control receiving unit 9506 Image receiving unit 9507 Battery 9508 Audio input unit 9509 Operation key 9510 Eyepiece unit

Claims (18)

A quinoxaline derivative represented by the general formula (1).

(Wherein, R ¹ to R ¹² may be the same as or different from each other, a hydrogen atom or a halogen atom, or an alkyl group, or an alkoxy group, or an acyl group, or a dialkylamino group, or a diarylamino group, or vinyl group, or represents. the one of the aryl groups, ^{R 9} and ^{R 10, R 10} and ^{R 11, R 11} and ^{R 12} are bonded to each other, they may form a condensed ring. further, Ar ¹ represents a biphenyl radical or data Feniru group, Ar ² represents a full Eniru group or a biphenyl group or terphenyl group,.) A quinoxaline derivative represented by the general formula (2).

(Wherein, R ⁹ to R ¹² may be the same as or different from each other, a hydrogen atom or a halogen atom, or an alkyl group, or an alkoxy group, or an acyl group, or a dialkylamino group, or a diarylamino group, or vinyl-group, or represents. the one of the aryl groups, ^{R 9} and ^{R 10, R 10} and ^{R 11, R 11} and ^{R 12} are bonded to each other, they may form a condensed ring. further , Ar ¹ is biphenyl group, or represents a data Feniru group, Ar ² represents a full Eniru group or a biphenyl group, or terphenyl group.) A quinoxaline derivative represented by the general formula (3).

(Wherein, R ⁹ to R ¹² may be the same as or different from each other, a hydrogen atom or a halogen atom, or an alkyl group, or an alkoxy group, or an acyl group, or a dialkylamino group, or a diarylamino group, or vinyl-group, or represents. the one of the aryl groups, ^{R 9} and ^{R 10, R 10} and ^{R 11, R 11} and ^{R 12} are bonded to each other, they may form a condensed ring. further , a represents a substituent represented by the structural formula (4) or structural formula (5), Ar ² represents a full Eniru group or a biphenyl group, or terphenyl group.) A quinoxaline derivative represented by the general formula (6).

(Wherein, R ⁹ to R ¹² may be the same as or different from each other, a hydrogen atom or a halogen atom, or an alkyl group, or an alkoxy group, or an acyl group, or a dialkylamino group, or a diarylamino group, or vinyl-group, or represents. the one of the aryl groups, ^{R 9} and ^{R 10, R 10} and ^{R 11, R 11} and ^{R 12} are bonded to each other, they may form a condensed ring. further A represents a substituent represented by Structural Formula (7) or Structural Formula (8), and B represents a hydrogen atom or a substituent represented by Structural Formula (7) or Structural Formula (8). A quinoxaline derivative represented by the general formula (9).

Wherein A represents a substituent represented by Structural Formula (10) or Structural Formula (11), and B represents a hydrogen atom, or a substituent represented by Structural Formula (10) or Structural Formula (11). To express.) A quinoxaline derivative represented by the structural formula (14).
A quinoxaline derivative represented by a structural formula (39):
  A light-emitting element having the quinoxaline derivative according to any one of claims 1 to 7 between a pair of electrodes. Having a light emitting layer between a pair of electrodes,
The light emitting layer includes the quinoxaline derivative according to any one of claims 1 to 7. Having a light emitting layer between a pair of electrodes,
The light-emitting layer includes the quinoxaline derivative according to any one of claims 1 to 7 and a fluorescent substance.   A light-emitting element having a light-emitting layer between a pair of electrodes, wherein the light-emitting layer includes the quinoxaline derivative according to any one of claims 1 to 7 and a phosphorescent substance. The light-emitting element according to claim 11, wherein the phosphorescent substance is an organometallic complex including a structure represented by the general formula (101).

(Wherein R ^{1 to} R ⁵ each represent one of hydrogen, a halogen element, an acyl group, an alkyl group, an alkoxyl group, an aryl group, and a cyano group . Ar represents an aryl group . Represents a Group 9 element or a Group 10 element.) In claim 11,
The phosphorescent material is an organometallic complex represented by the general formula (104).

^(Wherein, R 1 to R ⁵ are each hydrogen, a halogen element, an acyl group, an alkyl group, an alkoxyl group, an aryl group, .M the Group 9 .Ar is representative of the aryl group represented by any one of a cyano group Represents an element or a group 10 element, n = 2 when M is a group 9 element and n = 1 when M is a group 10 element L is a monoanionic arrangement having a beta diketone structure. It represents either a ligand or a monoanionic bidentate chelate ligand having a carboxyl group or a monoanionic bidentate chelate ligand having a phenolic hydroxyl group.) In claim 11,
The phosphorescent material is an organometallic complex represented by the general formula (105).

(In the formula, R ¹¹ represents any one of alkyl groups having 1 to 4 carbon atoms, and R ^{12 to} R ¹⁵ represent hydrogen, halogen element, acyl group, alkyl group, alkoxyl group, aryl group, cyano, respectively. It represents any of groups. Further, R ¹⁶ to R ¹⁹ are each hydrogen, an acyl group, an alkyl group, an alkoxyl group, an aryl group, and an electron-withdrawing substituent. Further, M group 9 Represents an element or a group 10 element, n = 2 when M is a group 9 element and n = 1 when M is a group 10 element L is a monoanionic arrangement having a beta diketone structure. It represents either a ligand or a monoanionic bidentate chelate ligand having a carboxyl group or a monoanionic bidentate chelate ligand having a phenolic hydroxyl group.) In claim 11,
The phosphorescent substance is an organometallic complex represented by the general formula (106).

(Wherein R ^{22 to} R ³⁴ each represent hydrogen, a halogen element, an acyl group, an alkyl group, an alkoxyl group, an aryl group, a cyano group, or an electron-withdrawing substituent. M represents a Group 9 element. Or M represents a Group 9 element or a Group 10 element, n = 2 when M is a Group 9 element, and n = 1 when M is a Group 10 element. L is a monoanionic ligand having a beta diketone structure, a monoanionic bidentate chelate ligand having a carboxyl group, or a monoanionic bidentate chelate ligand having a phenolic hydroxyl group Represents one of the following.) In any one of Claims 11 thru | or 15,
A light-emitting element, wherein a peak of an emission spectrum of the phosphorescent substance is 560 nm to 700 nm.   A light emitting device comprising: the light emitting element according to claim 8; and a control unit that controls light emission of the light emitting element. Having a display,
The electronic device comprising: the light emitting element according to any one of claims 8 to 16; and a control unit that controls light emission of the light emitting element.