JP2018131407A - Light emitting element, light emitting device, electronic apparatus and illumination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel organic compound or a light emitting element material, provide an organic compound or a light emitting element material with a high T1 level, and provide an organic compound or a light emitting element material suitable for a host material or a carrier transportation material of a blue phosphor element.SOLUTION: The present invention provides an organic compound or a light emitting element material that contains a pyrimidine skeleton having an alkyl group at position 5 and phenylene groups each having a substituent at a meta position, at positions 4 and 6, and has a molecular weight of 3000 or less. The organic compound or light emitting element material preferably has a substituent at each of two phenylene groups, the substituent preferably containing a carbazole skeleton, a fluorene skeleton, a dibenzothiophene skeleton or a dibenzofuran skeleton.SELECTED DRAWING: None

Description

One embodiment of the present invention relates to a light-emitting element, a display module, a lighting module, a display device, a light-emitting device, an electronic device, and a lighting device. Note that one embodiment of the present invention is not limited to the above technical field. The technical field of one embodiment of the invention disclosed in this specification and the like relates to an object, a method, or a manufacturing method. Alternatively, one embodiment of the present invention relates to a process, a machine, a manufacture, or a composition (composition of matter). Therefore, the technical field of one embodiment of the present invention disclosed in this specification more specifically includes a semiconductor device, a display device, a liquid crystal display device, a light-emitting device, a lighting device, a power storage device, a memory device, an imaging device, A driving method or a manufacturing method thereof can be given as an example.

  Practical use of light-emitting elements (organic EL elements) using electroluminescence (EL) using organic compounds has been progressing. The basic structure of these light-emitting elements is such that an organic compound layer (EL layer) containing a light-emitting material is sandwiched between a pair of electrodes. Light emission from the light-emitting material can be obtained by applying a voltage to this element, injecting carriers, and utilizing the recombination energy of the carriers.

  Since such a light-emitting element is a self-luminous type, when used as a display pixel, it has advantages such as higher visibility than liquid crystal and the need for a backlight, and is suitable as a flat panel display element. In addition, a display using such a light emitting element has a great advantage that it can be manufactured to be thin and light. Another feature is that the response speed is very fast.

  In addition, since these light emitting elements can continuously form a light emitting layer in two dimensions, light emission can be obtained in a planar shape. This is a feature that is difficult to obtain with a point light source typified by an incandescent bulb or LED, or a line light source typified by a fluorescent lamp, and therefore has a high utility value as a surface light source applicable to illumination or the like.

  As described above, a display and a lighting device using a light-emitting element are suitable for application to various electronic devices. However, research and development are being pursued for a light-emitting element having better efficiency and lifetime.

As one method for realizing a light-emitting element having good efficiency, a light-emitting element using a phosphorescent material has been actively developed. Red, green, and other elements have been put into practical use, but blue phosphorescent elements are currently under development.

Regarding blue phosphorescent devices, in addition to the development of light-emitting substances that emit blue light, it is also essential to develop host materials that can disperse and emit light efficiently. Patent Document 1 discloses a host material having a high T1 level and capable of exciting a blue phosphorescent material.

JP 2016-213470 A

In view of the above, an object of one embodiment of the present invention is to provide a novel organic compound or a material for a light-emitting element. Another object of one embodiment of the present invention is to provide an organic compound or a light-emitting element material having a high T1 level. Another object of another embodiment of the present invention is to provide an organic compound or a light-emitting element material suitable for a host material or a carrier transport material of a blue phosphorescent element.

Another object of one embodiment of the present invention is to provide a light-emitting element with favorable emission efficiency. Another object is to provide a light-emitting element with favorable color purity. It is an object to provide a light-emitting element with favorable light emission efficiency. Another object is to provide a light-emitting element with favorable color purity.

Another object of one embodiment of the present invention is to provide a highly reliable light-emitting device, electronic device, and display device. Another object of one embodiment of the present invention is to provide a light-emitting device, an electronic device, and a display device each with low power consumption. Another object of one embodiment of the present invention is to provide a light-emitting device, an electronic device, and a display device each with favorable display quality.

The present invention should solve any one of the above-mentioned problems.

One embodiment of the present invention is an organic compound represented by General Formula (G1) below.

However, in General Formula (G1), R ¹ represents any one of an alkyl group having 1 to 6 carbon atoms, and is independently represented by the following General Formula (G2-1) or ( The group represented by G2-2) is bonded.

However, in General Formula (G2-1), X ¹ represents any ^one of a nitrogen atom, an oxygen atom, a sulfur atom, and a carbon atom. When X ¹ is a nitrogen atom or a carbon atom, the nitrogen atom may have one and the carbon atom may have one or two substituents. R ^{11 to} R ¹⁸ each independently represents any one of hydrogen and an alkyl group having 1 to 6 carbon atoms. Note that one of R ^{11 to} R ¹⁴ may be a bond, and when X ¹ is nitrogen, the position of A in the general formula (G1) depends on any one of the bonds of the nitrogen. Or carbon at the B position.

However, in General Formula (G2-2), X ² represents any one of a nitrogen atom, an oxygen atom, a sulfur atom, and a carbon atom. When X ² is a nitrogen atom or a carbon atom, the nitrogen atom may have one substituent and the carbon atom may have one or two substituents. R ^{21 to} R ²⁸ each independently represents any one of hydrogen and an alkyl group having 1 to 6 carbon atoms. Note that one of R ^{21 to} R ²⁴ may be a bond, and in the case where the bond or X ² is nitrogen, one of the bonds of nitrogen has a bond of A in General Formula (G1). Bonds to carbon at position B or carbon at position B. In addition, α and β represent a ring condensed with two adjacent rings, α represents a ring represented by the following general formula (G3), and β represents a ring represented by the following general formula (G4).

The ring represented by the general formula (G3) is fused with two adjacent rings at the position of ac or the position of ad in the formula (G3). R ³¹ and R ³² each independently represent hydrogen or any one of an alkyl group having 1 to 6 carbon atoms.

The ring represented by the general formula (G4) is condensed with two adjacent rings at the position bd in the formula (G4). X ³ represents any one of a nitrogen atom, an oxygen atom, a sulfur atom, and a carbon atom. When X ³ is a nitrogen atom or a carbon atom, the nitrogen atom may have one substituent, and the carbon atom may have one or two substituents.

Another embodiment of the present invention is an organic compound represented by General Formula (G1) below.

However, in General Formula (G1), R ¹ represents any one of an alkyl group having 1 to 6 carbon atoms, and is independently represented by the following General Formula (G2-1) on each of carbon atoms at positions A and B. Group to be bonded.

However, in General Formula (G2-1), X ¹ represents any ^one of a nitrogen atom, an oxygen atom, a sulfur atom, and a carbon atom. When 1 is a nitrogen atom or a carbon atom, the nitrogen atom may have one and the carbon atom may have one or two substituents. R ^{11 to} R ¹⁸ each independently represents any one of hydrogen and an alkyl group having 1 to 6 carbon atoms. Note that one of R ^{11 to} R ¹⁴ may be a bond. When X ¹ is nitrogen, the position of A in the general formula (G1) depends on any one of the bonds of nitrogen. Or carbon at the B position.

Another embodiment of the present invention is an organic compound having the above structure, in which at least one of X ¹ is a nitrogen atom.

Another embodiment of the present invention is an organic compound in which, in the above structure, nitrogen of X ¹ is bonded to carbon at position A or carbon at position B in General Formula (G1).

Another embodiment of the present invention is an organic compound including an organic compound represented by General Formula (G1) below.

However, in General Formula (G1), R ¹ represents any one of alkyl groups having 1 to 6 carbon atoms, and independently of the carbon atoms at positions A and B, the following General Formula (G2-2)
A group represented by

However, in General Formula (G2-2), X ² represents any one of a nitrogen atom, an oxygen atom, a sulfur atom, and a carbon atom. When X ² is a nitrogen atom or a carbon atom, the nitrogen atom may have one substituent and the carbon atom may have one or two substituents. R ^{21 to} R ²⁸ each independently represents any one of hydrogen and an alkyl group having 1 to 6 carbon atoms. Note that one of R ^{21 to} R ²⁴ may be a bond. When X ² is nitrogen, the position of A in the general formula (G1) depends on any one of the bonds of nitrogen. Or carbon at the B position. Α and β represent a ring fused with two adjacent rings, α represents a ring represented by the following general formula (G3), and β represents a ring represented by the following general formula (G4).

The ring represented by the general formula (G3) is condensed with two adjacent rings at the position of ac or ad in formula (G3). R ³¹ and R ³² each independently represent hydrogen or any one of an alkyl group having 1 to 6 carbon atoms.

The ring represented by the general formula (G4) is condensed with two adjacent rings at the position of bd in the formula (G4), and X ³ is any one of a nitrogen atom, an oxygen atom, a sulfur atom and a carbon atom. Represents. When X ³ is a nitrogen atom or a carbon atom, the nitrogen atom may have one substituent, and the carbon atom may have one or two substituents.

Another embodiment of the present invention is an organic compound in which at least one of X ² is a nitrogen atom in the above structure.

Another embodiment of the present invention is an organic compound in which, in the above structure, nitrogen of X ² is bonded to carbon at position A or carbon at position B in General Formula (G1).

Another embodiment of the present invention is an organic compound represented by General Formula (G5) below.

However, in the formula represented by the general formula (G5), R ¹ represents an alkyl group having 1 to 6 carbon atoms, and R ^{41 to} R ⁴⁸ and R ^{51 to} R ⁵⁸ are each independently hydrogen or 1 to C carbon atoms. Represents any one of 6 alkyl groups;

Another embodiment of the present invention is an organic compound represented by General Formula (G6) below.

Another embodiment of the present invention is an organic compound represented by the following general formulas (G7) to (G10).

However, in General Formulas (G7) to (G10), R ¹ represents an alkyl group having 1 to 6 carbon atoms.

Another embodiment of the present invention is an organic compound represented by the following general formula (g1).

However, in General Formula (g1), R ² represents any one of an alkyl group having 1 to 6 carbon atoms.

Another embodiment of the present invention is an organic compound represented by the following structural formula (100).

Another embodiment of the present invention is a light-emitting element having an organic compound having a skeleton represented by the following general formula (G1) and having a molecular weight of 3000 or less.

However, in General Formula (G1), R ¹ represents any one of an alkyl group having 1 to 6 carbon atoms, and each of the carbon atoms at positions A and B has a substituent.

Another embodiment of the present invention is a light-emitting element having an organic compound having a skeleton represented by the following general formula (G1) and having a molecular weight of 3000 or less.

Note that in General Formula (G1), R ¹ represents any one of an alkyl group having 1 to 6 carbon atoms, and has a substituent containing a carbazole skeleton at each of the carbon atoms at positions A and B.

Another embodiment of the present invention is a light-emitting element including any of the above organic compounds.

Another embodiment of the present invention is a light-emitting element having the above structure, in which the light-emitting element includes at least a light-emitting layer, and the light-emitting layer includes the organic compound.

Another embodiment of the present invention is a light-emitting device including the light-emitting element having the above structure and a transistor or a substrate.

Another embodiment of the present invention is an electronic device including the light-emitting device described above and a sensor, an operation button, a speaker, or a microphone.

Another embodiment of the present invention is a lighting device including a light-emitting device having the above structure and a housing.

Another embodiment of the present invention is a light-emitting device including the light-emitting element having the above structure and a transistor or a substrate.

Another embodiment of the present invention is an electronic device including the light-emitting device having the above structure and a sensor, an operation button, a speaker, or a microphone.

Another embodiment of the present invention is a lighting device including the light-emitting device having the above structure and a housing.

Note that the light-emitting device in this specification includes an image display device using a light-emitting element. In addition, a module in which a connector such as an anisotropic conductive film or TCP (Tape Carrier Package) is attached to the light emitting element, a module in which a printed wiring board is provided at the end of TCP, or a COG (Chip On Glass) system in the light emitting element A module on which an IC (integrated circuit) is directly mounted may have a light emitting device. Furthermore, a lighting fixture or the like may include a light emitting device.

  In one embodiment of the present invention, a light-emitting element with favorable lifetime can be provided. Alternatively, a light-emitting element with favorable light emission efficiency can be provided. Alternatively, a light-emitting element with favorable color purity can be obtained. Alternatively, in one embodiment of the present invention, a novel organic compound can be provided.

Alternatively, according to another embodiment of the present invention, a highly reliable light-emitting device, electronic device, and display device can be provided. Alternatively, according to another embodiment of the present invention, a light-emitting device, an electronic device, and a display device with low power consumption can be provided. Alternatively, according to another embodiment of the present invention, a light-emitting device, an electronic device, and a display device each having favorable display quality can be provided.

Note that the description of these effects does not disturb the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. It should be noted that the effects other than these are naturally obvious from the description of the specification, drawings, claims, etc., and it is possible to extract the other effects from the descriptions of the specification, drawings, claims, etc. It is.

Schematic of a light emitting element. 10A and 10B illustrate an example of a method for manufacturing a light-emitting element. 10A and 10B illustrate an example of a method for manufacturing a light-emitting element. 1 is a conceptual diagram of an active matrix light-emitting device. 1 is a conceptual diagram of an active matrix light-emitting device. 1 is a conceptual diagram of an active matrix light-emitting device. 1 is a conceptual diagram of a passive matrix light emitting device. The figure showing an illuminating device. FIG. 10 illustrates an electronic device. The figure showing a light source device. The figure showing an illuminating device. The figure showing an illuminating device. The figure showing a vehicle-mounted display apparatus and an illuminating device. FIG. 10 illustrates an electronic device. FIG. 10 illustrates an electronic device. ¹ H-NMR data of 5Me-4,6mCzP2Pm. The absorption spectrum and emission spectrum in the toluene solution of 5Me-4,6mCzP2Pm. Absorption spectrum and emission spectrum in a thin film of 5Me-4,6mCzP2Pm. Luminance-current density characteristics of the light-emitting element 1, the comparative light-emitting element 1, and the comparative light-emitting element 2. Luminance-voltage characteristics of the light-emitting element 1, the comparative light-emitting element 1, and the comparative light-emitting element 2. The current efficiency-luminance characteristics of the light-emitting element 1, the comparative light-emitting element 1, and the comparative light-emitting element 2. The current-voltage characteristics of the light-emitting element 1, the comparative light-emitting element 1, and the comparative light-emitting element 2. Chromaticity-luminance characteristics of the light-emitting element 1, the comparative light-emitting element 1, and the comparative light-emitting element 2. External quantum efficiency-luminance characteristics of the light-emitting element 1, the comparative light-emitting element 1, and the comparative light-emitting element 2. The emission spectrum of the light emitting element 1, the comparative light emitting element 1, and the comparative light emitting element 2. FIG. 6 shows normalized luminance time change characteristics of the light-emitting element 1, the comparative light-emitting element 1, and the comparative light-emitting element 2.

  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)
A light-emitting element of one embodiment of the present invention includes an organic compound including a pyrimidine skeleton having a phenylene group having an alkyl group at the 5-position and a substituent at the 4-position and the 6-position and having a molecular weight of 3000 or less. It is the used light emitting element. Moreover, the said organic compound has a substituent in two phenylene groups, respectively.

Since the organic compound is a substance having a high band gap and a high T1 level, the organic compound can be very preferably used as a host material of a phosphorescent light-emitting element. In addition, since the organic compound is excellent in electron transport properties, it is also suitable as a material constituting the electron transport layer.

In addition, since the above organic compound has an alkyl group bonded to the 5-position of the pyrimidine skeleton, twisting of the phenylene group is caused, and an organic compound having a relatively low LUMO can be obtained. In addition, the T1 level can be increased by an alkyl group bonded to the 5-position of the pyrimidine skeleton.

Many phosphorescent materials (especially green to blue phosphorescent materials) have high (shallow) HOMO levels, and the host material and the phosphorescent material may form an exciplex. is there. When an exciplex is formed between the phosphorescent substance and the host material, light emission from the phosphorescent substance cannot be obtained. In addition, the obtained light emission may have an influence such as a decrease in efficiency due to a mixture of light emission from the exciplex and deterioration in reliability.

Here, since the LUMO level of the organic compound is relatively shallow as described above, it is difficult to form an exciplex with a phosphorescent material, and the color purity is decreased due to a change in the emission spectrum, the emission efficiency is decreased, It is possible to suppress a decrease in reliability.

In addition, since the above organic compound has a higher T1 level due to an alkyl group bonded to the 5-position, a phosphorescent material having a high green to blue triplet excitation level is particularly used as a luminescent substance. It is particularly suitable as a host material or a carrier transport material for the used light emitting device.

In addition, as a group substituted by the phenylene group of the said organic compound, the substituent which has a carbazole skeleton is preferable.

The light-emitting element having the above structure can also be referred to as a light-emitting element including an organic compound represented by the following general formula (G1) and having a molecular weight of 3000 or less.

However, in General Formula (G1), R ¹ represents any one of an alkyl group having 1 to 6 carbon atoms, and each of the carbon atoms at positions A and B has a substituent.

Another embodiment of the present invention is a light-emitting element including an organic compound having a skeleton represented by the following general formula (G1) and having a molecular weight of 3000 or less.

Note that in General Formula (G1), R ¹ represents any one of an alkyl group having 1 to 6 carbon atoms, and has a substituent containing a carbazole skeleton at each of the carbon atoms at positions A and B.

It has been described that the above organic compound has an LUMO level and a T1 level by having an alkyl group at the 5-position. Here, the HOMO level, LUMO level, band gap, and T1 level of three similar substances were calculated and compared. The structural formula of the substance is shown below.

Among the substances having the above structural formula, (1) is an organic compound including a pyrimidine skeleton having a phenylene group having an alkyl group at the 5-position and a substituent at the 4-position and the 6-position at the meta position, 2) an organic compound containing a pyrimidine skeleton having a phenylene group having an alkyl group at the 2-position and a substituent at the 4-position and the 6-position, and (3) an alkyl group at both the 5-position and 2-position Is an organic compound containing a pyrimidine skeleton having a phenylene group having a substituent at the meta position at the 4th and 6th positions.

For the calculation, a quantum chemical calculation program, Gaussian 09, was used, and a high performance computer (ICE X, manufactured by SGI) was used.

First, the most stable structure in the singlet ground state was calculated by the density functional theory (DFT). 6-311G (d, p) was used as a basis function. The functional was B3LYP. Next, using the time-dependent density functional theory (TD-DFT), the energy related to the transition from the most stable structure of the singlet ground state to the singlet excited state and the triplet excited state was calculated. Note that the total energy of DFT is represented by the sum of potential energy, electrostatic energy between electrons, and exchange correlation energy including all the interactions between kinetic energy of electrons and complex electrons. In DFT, the exchange correlation interaction is approximated by a functional (meaning function) of one electron potential expressed by electron density. The results are shown below.

Thus, an organic compound including a pyrimidine skeleton having a phenylene group having an alkyl group at the 5-position and a substituent at the 4-position and the 6-position has the same structure and is located at the 2-position of the pyrimidine skeleton. It can be seen that the LUMO level is shallower by 0.2 eV or more than the substance having an alkyl group in and a substance having no alkyl group in the pyrimidine skeleton. Further, the T1 level was also larger by 0.1 eV or more, and it was found that such a large difference appears depending on the presence or absence of an alkyl group in the pyrimidine skeleton and a slight difference in the position. This can be said to be particularly suitable for use as a host material or a carrier transport material of a green to blue phosphorescent light emitting device.

FIG. 1 illustrates a light-emitting element of one embodiment of the present invention. A light-emitting element of one embodiment of the present invention includes an anode 101, a cathode 102, and an EL layer 103, and the above organic compound is used for the EL layer.

The EL layer 103 includes a light emitting layer 113 and may include a hole transport layer 112. The light-emitting layer 113 includes a light-emitting material and a host material, and the light-emitting element of one embodiment of the present invention emits light from the light-emitting material. The light-emitting element of one embodiment of the present invention can be applied particularly preferably when the light-emitting material is a phosphorescent material, particularly a phosphorescent material that exhibits green to blue phosphorescence. The organic compound of one embodiment of the present invention may be included in the light-emitting layer 113, the electron transport layer 114, or any of them, and may be included in another layer. I do not care.

In addition to the above, FIG. 1 shows a hole injection layer 111, a hole transport layer 112, and an electron injection layer 115, but the structure of the light-emitting element is not limited thereto.

The organic compound is preferably used as a host material. Moreover, the structure which forms the exciplex by the said organic compound and the said positive hole transport material by co-evaporating with a positive hole transport material in the light emitting layer may be sufficient. By forming an exciplex having an appropriate emission wavelength, effective energy transfer to the light-emitting material can be realized, and a light-emitting element having high efficiency and good lifetime can be provided. At this time, since the emission spectrum of the exciplex formed by the organic compound and the hole transport material overlaps with the absorption band on the longest wavelength side of the light emitting material, energy transfer can be efficiently performed. Become.

In addition, when the organic compound has an alkyl group at the 5-position of the pyrimidine skeleton, the LUMO level can be made much shallower than that of an organic compound with a similar skeleton, and the formation of an exciplex with a light-emitting substance can be suppressed. Therefore, it is possible to suppress a decrease in light emission efficiency and a deterioration in reliability. Further, since the T1 level is also increased, it is preferably used for a light-emitting element using a light-emitting substance that emits phosphorescence of a short wavelength from green to blue.

  Next, examples of detailed structures and materials of the light-emitting element described above will be described. The light-emitting element of one embodiment of the present invention includes the EL layer 103 including a plurality of layers between the pair of electrodes of the anode 101 and the cathode 102 as described above, and the EL layer 103 includes at least the light-emitting layer 113.

  There are no particular limitations on the other layers included in the EL layer 103, such as a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, a carrier block layer, an exciton block layer, and a charge generation layer. Various layer structures can be applied.

  With respect to the stack structure of the EL layer 103, in this embodiment mode, as shown in FIG. 1A, in addition to the light-emitting layer 113, a hole injection layer 111, a hole transport layer 112, an electron transport layer 114, and an electron In addition to the structure having the injection layer 115 and the hole injection layer 111, the hole transport layer 112, and the light emitting layer 113, as shown in FIG. 1B, the electron transport layer 114, the electron injection layer 115, and the charge generation layer Two types of configurations having the configuration 116 will be described. The materials constituting the electrode and the EL layer are specifically shown below.

  The anode 101 is preferably formed using a metal, an alloy, a conductive compound, a mixture thereof, or the like having a high work function (specifically, 4.0 eV or more). Specifically, for example, indium tin oxide (ITO), indium oxide-tin oxide containing silicon or silicon oxide, indium oxide-zinc oxide, indium oxide containing zinc oxide and zinc oxide ( IWZO) and the like. These conductive metal oxide films are usually formed by a sputtering method, but may be formed by applying a sol-gel method or the like. As an example of a manufacturing method, indium oxide-zinc oxide can be formed by a sputtering method using a target in which 1 to 20 wt% of zinc oxide is added to indium oxide. Indium oxide containing tungsten oxide and zinc oxide (IWZO) is formed by sputtering using a target containing 0.5 to 5 wt% tungsten oxide and 0.1 to 1 wt% zinc oxide with respect to indium oxide. You can also 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). Graphene can also be used. Note that by using a composite material described later for a layer in contact with the anode 101 in the EL layer 103, an electrode material can be selected regardless of a work function.

The hole injection layer 111 is a layer containing a substance having an acceptor property. As the substance having an acceptor property, a compound having an electron withdrawing group (halogen group or cyano group) can be used, and 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane. (Abbreviation: F4-TCNQ), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviation: F6-TCNNQ), 3,6-difluoro-2,5,7,7 , 8,8-hexacyanoquinodimethane, chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HAT-CN) and other organic acceptors and molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, an inorganic oxide such as manganese oxide, other phthalocyanine (abbreviation: H 2 _Pc) or copper phthalonitrile Phthalocyanine-based metal complexes such as anine (CuPC), 4,4′-bis [N- (4-diphenylaminophenyl) -N-phenylamino] biphenyl (abbreviation: DPAB), N, N′-bis {4- Aromatic amine compounds such as [bis (3-methylphenyl) amino] phenyl} -N, N′-diphenyl- (1,1′-biphenyl) -4,4′-diamine (abbreviation: DNTPD), or poly ( Polymers such as 3,4-ethylenedioxythiophene) / poly (styrenesulfonic acid) (PEDOT / PSS) can be used.

As the organic acceptor, a compound in which an electron withdrawing group is bonded to a condensed aromatic ring having a plurality of heteroatoms such as HAT-CN is preferable because it is thermally stable. An organic compound having an acceptor property can extract electrons from an adjacent hole transport layer (or hole transport material) by application of an electric field.

  For the hole-injecting layer 111, a composite material in which an acceptor substance is contained in a substance having a hole-transport property can also be used. Note that by using a composite material in which an acceptor substance is contained in a hole-transporting substance, a material for forming an electrode can be selected regardless of a work function. That is, not only a material having a high work function but also a material having a low work function can be used for the anode 101. As the acceptor substance, the above-described organic acceptors, transition metal oxides, or oxides of metals belonging to Groups 4 to 8 in the periodic table can be used. As the oxides of metals belonging to Groups 4 to 8 in the periodic table, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, rhenium oxide, and the like have high electron accepting properties. Therefore, it is preferable. Among these, molybdenum oxide is especially preferable because it is stable in the air, has a low hygroscopic property, and is easy to handle. As the organic acceptor, 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ), chloranil, or the like is preferable.

The substance having a hole-transport property used for the composite material preferably has a hole mobility of 10 ⁻⁶ cm ² / Vs or higher. As the substance having the hole-transport property, N, N′-di (p-tolyl) -N, N′-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4′-bis [N- ( 4-diphenylaminophenyl) -N-phenylamino] biphenyl (abbreviation: DPAB), N, N′-bis {4- [bis (3-methylphenyl) amino] phenyl} -N, N′-diphenyl- (1 , 1′-biphenyl) -4,4′-diamine (abbreviation: DNTPD), 1,3,5-tris [N- (4-diphenylaminophenyl) -N-phenylamino] benzene (abbreviation: DPA3B), etc. Aromatic amine, 3- [N- (9-phenylcarbazol-3-yl) -N-phenylamino] -9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis [N- (9-phenylcarba) Zol-3-yl) -N-phenylamino] -9-phenylcarbazole (abbreviation: PCzPCA2), 3- [N- (1-naphthyl) -N- (9-phenylcarbazol-3-yl) amino] -9 -Phenylcarbazole (abbreviation: PCzPCN1), 4,4'-di (N-carbazolyl) biphenyl (abbreviation: CBP), 1,3,5-tris [4- (N-carbazolyl) phenyl] benzene (abbreviation: TCPB) , 9- [4- (10-phenyl-9-anthryl) phenyl] -9H-carbazole (abbreviation: CzPA), 1,4-bis [4- (N-carbazolyl) phenyl] -2,3,5,6 -Carbazole derivatives such as tetraphenylbenzene, 2-tert-butyl-9,10-di (2-naphthyl) anthracene (abbreviation: t-BuDNA), 2-ter t-butyl-9,10-di (1-naphthyl) anthracene, 9,10-bis (3,5-diphenylphenyl) anthracene (abbreviation: DPPA), 2-tert-butyl-9,10-bis (4- Phenylphenyl) anthracene (abbreviation: t-BuDBA), 9,10-di (2-naphthyl) anthracene (abbreviation: DNA), 9,10-diphenylanthracene (abbreviation: DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAnth), 9,10-bis (4-methyl-1-naphthyl) anthracene (abbreviation: DMNA), 2-tert-butyl-9,10-bis [2- (1-naphthyl) phenyl] anthracene, 9 , 10-bis [2- (1-naphthyl) phenyl] anthracene, 2,3,6,7-tetramethyl-9,10-di (1- Phthalyl) anthracene, 2,3,6,7-tetramethyl-9,10-di (2-naphthyl) anthracene, 9,9′-bianthryl, 10,10′-diphenyl-9,9′-bianthryl, 10, 10′-bis (2-phenylphenyl) -9,9′-bianthryl, 10,10′-bis [(2,3,4,5,6-pentaphenyl) phenyl] -9,9′-bianthryl, anthracene And aromatic hydrocarbons such as tetracene, pentacene, coronene, rubrene, perylene, 2,5,8,11-tetra (tert-butyl) perylene. The aromatic hydrocarbon may have a vinyl skeleton. As the aromatic hydrocarbon having a vinyl group, for example, 4,4′-bis (2,2-diphenylvinyl) biphenyl (abbreviation: DPVBi), 9,10-bis [4- (2,2- Diphenylvinyl) phenyl] anthracene (abbreviation: DPVPA) and the like. In addition, 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: NPB), N, N′-bis (3-methylphenyl) -N, N′-diphenyl- [ 1,1′-biphenyl] -4,4′-diamine (abbreviation: TPD), 4,4′-bis [N- (spiro-9,9′-bifluoren-2-yl) -N-phenylamino] biphenyl (Abbreviation: BSPB), 4-phenyl-4 ′-(9-phenylfluoren-9-yl) triphenylamine (abbreviation: BPAFLP), 4-phenyl-3 ′-(9-phenylfluoren-9-yl) tri Phenylamine (abbreviation: mBPAFLP), 4-phenyl-4 ′-(9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBA1BP), 4,4′-diphenyl-4 ″-(9 -Phenyl- 9-H-carbazol-3-yl) triphenylamine (abbreviation: PCBBi1BP), 4- (1-naphthyl) -4 ′-(9-phenyl-9H-carbazol-3-yl) -triphenylamine (abbreviation: PCBANB), 4,4′-di (1-naphthyl) -4 ″-(9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBNBB), 9,9-dimethyl-N-phenyl -N- [4- (9-phenyl-9H-carbazol-3-yl) phenyl] -fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N- [4- (9-phenyl-9H-carbazole) Compound having an aromatic amine skeleton such as -3-yl) phenyl] -spiro-9,9′-bifluoren-2-amine (abbreviation: PCBASF), 1,3-bis (N-cal) Zolyl) benzene (abbreviation: mCP), 4,4′-di (N-carbazolyl) biphenyl (abbreviation: CBP), 3,6-bis (3,5-diphenylphenyl) -9-phenylcarbazole (abbreviation: CzTP) , 3,3′-bis (9-phenyl-9H-carbazole) (abbreviation: PCCP) and other compounds having a carbazole skeleton, 4,4 ′, 4 ″-(benzene-1,3,5-triyl) tri (Dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4- [4- (9-phenyl-9H-fluoren-9-yl) phenyl] dibenzothiophene (abbreviation: DBTFLP-III), 4- Thiophene skeletons such as [4- (9-phenyl-9H-fluoren-9-yl) phenyl] -6-phenyldibenzothiophene (abbreviation: DBTFLP-IV) 4,4 ′, 4 ″-(benzene-1,3,5-triyl) tri (dibenzofuran) (abbreviation: DBF3P-II), 4- {3- [3- (9-phenyl-9H— A compound having a furan skeleton such as fluoren-9-yl) phenyl] phenyl} dibenzofuran (abbreviation: mmDBFFLBi-II) can be used. Among the compounds described above, a compound having an aromatic amine skeleton and a compound having a carbazole skeleton are preferable because they have good reliability, high hole transportability, and contribute to reduction in driving voltage.

The hole injection layer 111 can also be formed by a wet method. In this case, poly (ethylenedioxythiophene) / poly (styrenesulfonic acid) aqueous solution (PEDOT / PSS), polyaniline / camphorsulfonic acid aqueous solution (PANI / CSA), PTPDES, Et-PTPDK, or PPBA, polyaniline / poly (styrene) A conductive polymer compound to which an acid such as sulfonic acid (PANI / PSS) is added can be used.

  By forming the hole injecting layer 111, the hole injecting property is improved and a light emitting element with a low driving voltage can be obtained. An organic acceptor is an easy-to-use material because it can be easily deposited and easily formed into a film.

The hole transport layer 112 may be used as appropriate from the above-described materials having a hole transport property or from various other materials having a hole transport property.

The light emitting layer 113 includes a layer containing a fluorescent light emitting material, a layer containing a phosphorescent light emitting material, a layer containing a material that emits thermally activated delayed fluorescence (TADF), a layer containing quantum dots, and a layer containing metal halogen perovskites, etc. It may be a layer containing any luminescent substance. Further, it may be a single layer or a plurality of layers. In the case of forming a light-emitting layer including a plurality of layers, a layer containing a phosphorescent material and a layer containing a fluorescent material may be stacked. At this time, it is preferable to use an exciplex described later in the layer containing the phosphorescent material.

As the fluorescent light-emitting substance, for example, the following substances can be used. Other fluorescent materials can also be used. 5,6-bis [4- (10-phenyl-9-anthryl) phenyl] -2,2′-bipyridine (abbreviation: PAP2BPy), 5,6-bis [4 ′-(10-phenyl-9-anthryl) Biphenyl-4-yl] -2,2′-bipyridine (abbreviation: PAPP2BPy), (N, N′-diphenyl-N, N′-bis [4- (9-phenyl-9H-fluoren-9-yl) phenyl] ] Pyrene-1,6-diamine), N, N′-bis (3-methylphenyl) -N, N′-bis [3- (9-phenyl-9H-fluoren-9-yl) phenyl] pyrene-1 , 6-diamine (abbreviation: 1,6 mM emFLPAPrn), N, N′-bis [4- (9H-carbazol-9-yl) phenyl] -N, N′-diphenylstilbene-4,4′-diamine (abbreviation: YGA S), 4- (9H-carbazol-9-yl) -4 ′-(10-phenyl-9-anthryl) triphenylamine (abbreviation: YGAPA), 4- (9H-carbazol-9-yl) -4 ′ -(9,10-diphenyl-2-anthryl) triphenylamine (abbreviation: 2YGAPPA), N, 9-diphenyl-N- [4- (10-phenyl-9-anthryl) phenyl] -9H-carbazole-3- Amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra (tert-butyl) perylene (abbreviation: TBP), 4- (10-phenyl-9-anthryl) -4 ′-(9-phenyl- 9H-carbazol-3-yl) triphenylamine (abbreviation: PCBAPA), N, N ″-(2-tert-butylanthracene-9,10-diyldi-4 1-phenylene) bis [N, N ′, N′-triphenyl-1,4-phenylenediamine] (abbreviation: DPABPA), N, 9-diphenyl-N- [4- (9,10-diphenyl-2-) Anthryl) phenyl] -9H-carbazol-3-amine (abbreviation: 2PCAPPA), N- [4- (9,10-diphenyl-2-anthryl) phenyl] -N, N ′, N′-triphenyl-1, 4-phenylenediamine (abbreviation: 2DPAPPA), N, N, N ′, N ′, N ″, N ″, N ′ ″, N ′ ″-octaphenyldibenzo [g, p] chrysene-2, 7,10,15-tetraamine (abbreviation: DBC1), coumarin 30, N- (9,10-diphenyl-2-anthryl) -N, 9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA) ), N- [9,10-bis (1,1′-biphenyl-2-yl) -2-anthryl] -N, 9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPhA), N- ( 9,10-diphenyl-2-anthryl) -N, N ′, N′-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N- [9,10-bis (1,1′-biphenyl-) 2-yl) -2-anthryl] -N, N ′, N′-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), 9,10-bis (1,1′-biphenyl-2-yl) -N- [4- (9H-carbazol-9-yl) phenyl] -N-phenylanthracen-2-amine (abbreviation: 2YGABPhA), N, N, 9-triphenylanthracen-9-amine (abbreviation: D) hAPhA) Coumarin 545T, N, N′-diphenylquinacridone (abbreviation: DPQd), rubrene, 5,12-bis (1,1′-biphenyl-4-yl) -6,11-diphenyltetracene (abbreviation: BPT), 2- (2- {2- [4- (dimethylamino) phenyl] ethenyl} -6-methyl-4H-pyran-4-ylidene) propanedinitrile (abbreviation: DCM1), 2- {2-methyl-6- [2- (2,3,6,7-tetrahydro-1H, 5H-benzo [ij] quinolizin-9-yl) ethenyl] -4H-pyran-4-ylidene} propanedinitrile (abbreviation: DCM2), N, N, N ′, N′-tetrakis (4-methylphenyl) tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N, N, N ′, N ′ Tetrakis (4-methylphenyl) acenaphtho [1,2-a] fluoranthene-3,10-diamine (abbreviation: p-mPhAFD), 2- {2-isopropyl-6- [2- (1,1,7,7 -Tetramethyl-2,3,6,7-tetrahydro-1H, 5H-benzo [ij] quinolizin-9-yl) ethenyl] -4H-pyran-4-ylidene} propanedinitrile (abbreviation: DCJTI), 2- {2-tert-butyl-6- [2- (1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H, 5H-benzo [ij] quinolizin-9-yl) ethenyl] -4H-pyran-4-ylidene} propanedinitrile (abbreviation: DCJTB), 2- (2,6-bis {2- [4- (dimethylamino) phenyl] ethenyl} -4H-pyran-4-ylidene ) Propanedinitrile (abbreviation: BisDCM), 2- {2,6-bis [2- (8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H, 5H) -Benzo [ij] quinolizin-9-yl) ethenyl] -4H-pyran-4-ylidene} propanedinitrile (abbreviation: BisDCJTM) and the like. In particular, condensed aromatic diamine compounds typified by pyrenediamine compounds such as 1,6FLPAPrn and 1,6mMemFLPAPrn are preferable because they have high hole trapping properties and are excellent in luminous efficiency and reliability.

Examples of materials that can be used as the phosphorescent material in the light-emitting layer 113 include the following. Tris {2- [5- (2-methylphenyl) -4- (2,6-dimethylphenyl) -4H-1,2,4-triazol-3-yl-κN2] phenyl-κC} iridium (III) ( Abbreviations: [Ir (mpptz-dmp) ₃ ]), tris (5-methyl-3,4-diphenyl-4H-1,2,4-triazolato) iridium (III) (abbreviation: [Ir (Mptz) ₃ ]) 4H, such as Tris [4- (3-biphenyl) -5-isopropyl-3-phenyl-4H-1,2,4-triazolate] iridium (III) (abbreviation: [Ir (iPrptz-3b) ₃ ]) An organometallic iridium complex having a triazole skeleton or tris [3-methyl-1- (2-methylphenyl) -5-phenyl-1H-1,2,4-triazolate] iridium (II I) (abbreviation: [Ir (Mptz1-mp) ₃ ]), tris (1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato) iridium (III) (abbreviation: [Ir ( Organometallic iridium complexes having a 1H-triazole skeleton such as Prptz1-Me) ₃ ]) and fac-tris [1- (2,6-diisopropylphenyl) -2-phenyl-1H-imidazole] iridium (III) ( Abbreviation: [Ir (iPrpmi) ₃ ]), tris [3- (2,6-dimethylphenyl) -7-methylimidazo [1,2-f] phenanthridinato] iridium (III) (abbreviation: [Ir ( organometallic iridium complexes having an imidazole skeleton such as dmpimpt-Me) ₃ ]) and bis [2- (4 ′, 6′-difluorophenyl) pyri Dinato-N, C ^{2 ′} ] iridium (III) tetrakis (1-pyrazolyl) borate (abbreviation: FIr6), bis [2- (4 ′, 6′-difluorophenyl) pyridinato-N, C ^{2 ′} ] iridium (III ) Picolinate (abbreviation: FIrpic), bis {2- [3 ′, 5′-bis (trifluoromethyl) phenyl] pyridinato-N, C ^{2 ′} } iridium (III) picolinate (abbreviation: [Ir (CF ₃ ppy) ₂ (pic)]), phenyl having an electron withdrawing group such as bis [2- (4 ′, 6′-difluorophenyl) pyridinato-N, C ^{2 ′} ] iridium (III) acetylacetonate (abbreviation: FIracac). And organometallic iridium complexes having a pyridine derivative as a ligand. These are compounds that exhibit blue phosphorescence emission, and are compounds having an emission peak from 440 nm to 520 nm.

In addition, tris (4-methyl-6-phenylpyrimidinato) iridium (III) (abbreviation: [Ir (mppm) ₃ ]), tris (4-t-butyl-6-phenylpyrimidinato) iridium (III) (Abbreviation: [Ir (tBupppm) ₃ ]), (acetylacetonato) bis (6-methyl-4-phenylpyrimidinato) iridium (III) (abbreviation: [Ir (mppm) ₂ (acac)]), ( Acetylacetonato) bis (6-tert-butyl-4-phenylpyrimidinato) iridium (III) (abbreviation: [Ir (tBupppm) ₂ (acac)]), (acetylacetonato) bis [6- (2- Norbornyl) -4-phenylpyrimidinato] iridium (III) (abbreviation: [Ir (nbppm) ₂ (acac)]), (acetylacetonato ) Bis [5-methyl-6- (2-methylphenyl) -4-phenylpyrimidinato] iridium (III) (abbreviation: [Ir (mpmppm) ₂ (acac)]), (acetylacetonato) bis (4 , 6-diphenylpyrimidinato) iridium (III) (abbreviation: [Ir (dppm) ₂ (acac)]) or an organometallic iridium complex having a pyrimidine skeleton, or (acetylacetonato) bis (3,5- Dimethyl-2-phenylpyrazinato) iridium (III) (abbreviation: [Ir (mppr-Me) ₂ (acac)]), (acetylacetonato) bis (5-isopropyl-3-methyl-2-phenylpyrazina) Doo) iridium (III) _{(abbreviation: [Ir (mppr-iPr)} 2 (acac)] organometallic Ili with) pyrazine skeleton, such as And um complex, tris (2-phenylpyridinato--N, C ^{2 ')} iridium (III) _{(abbreviation: [Ir (ppy) 3]} ), bis (2-phenylpyridinato--N, C ^2') Iridium (III) acetylacetonate (abbreviation: [Ir (ppy) ₂ (acac)]), bis (benzo [h] quinolinato) iridium (III) acetylacetonate (abbreviation: [Ir (bzq) ₂ (acac)] ), Tris (benzo [h] quinolinato) iridium (III) (abbreviation: [Ir (bzq) ₃ ]), tris (2-phenylquinolinato-N, C ^{2 ′} ) iridium (III) (abbreviation: [Ir ( pq) ₃ ]), bis (2-phenylquinolinato-N, C ^{2 ′} ) iridium (III) acetylacetonate (abbreviation: [Ir (pq) ₂ (acac)]). In addition to an organometallic iridium complex having a lysine skeleton, a rare earth metal complex such as tris (acetylacetonato) (monophenanthroline) terbium (III) (abbreviation: [Tb (acac) ₃ (Phen)]) can be given. These are compounds which emit green phosphorescence mainly, and have a light emission peak at 500 nm to 600 nm. Note that an organometallic iridium complex having a pyrimidine skeleton is particularly preferable because of its outstanding reliability and luminous efficiency.

In addition, (diisobutyrylmethanato) bis [4,6-bis (3-methylphenyl) pyrimidinato] iridium (III) (abbreviation: [Ir (5 mdppm) ₂ (divm)]), bis [4,6-bis ( 3-methylphenyl) pyrimidinato] (dipivaloylmethanato) iridium (III) (abbreviation: [Ir (5 mdppm) ₂ (dpm)]), bis [4,6-di (naphthalen-1-yl) pyrimidinato] ( Organometallic iridium complexes having a pyrimidine skeleton such as dipivaloylmethanato) iridium (III) (abbreviation: [Ir (d1npm) ₂ (dpm)]), and (acetylacetonato) bis (2,3,5- tri phenylpyrazinato) iridium (III) _{(abbreviation: [Ir (tppr) 2 (} acac)]), bis (2,3,5-triphenyl Rajinato) (dipivaloylmethanato) iridium (III) _{(abbreviation: [Ir (tppr) 2 (} dpm])]), ( acetylacetonato) bis [2,3-bis (4-fluorophenyl) quinoxalinato] iridium (III) (abbreviation: [Ir (Fdpq) ₂ (acac)]) or an organometallic iridium complex having a pyrazine skeleton, or tris (1-phenylisoquinolinato-N, C ^{2 ′} ) iridium (III) ( Abbreviations: [Ir (piq) ₃ ]), bis (1-phenylisoquinolinato-N, C ^{2 ′} ) iridium (III) acetylacetonate (abbreviation: [Ir (piq) ₂ (acac)]) In addition to organometallic iridium complexes having a pyridine skeleton, 2,3,7,8,12,13,17,18-octaethyl-21H, 23H-porphy Emissions platinum (II) (abbreviation: PtOEP) and platinum complexes such as tris (1,3-diphenyl-1,3-propanedionato) (monophenanthroline) europium (III) (abbreviation: [Eu _{(DBM) 3} (Phen)]), tris [1- (2-thenoyl) -3,3,3-trifluoroacetonato] (monophenanthroline) europium (III) (abbreviation: [Eu (TTA) ₃ (Phen)]) Such rare earth metal complexes are mentioned. These are compounds that exhibit red phosphorescence, and have an emission peak from 600 nm to 700 nm. An organometallic iridium complex having a pyrazine skeleton can emit red light with good chromaticity.

  In addition to the phosphorescent compounds described above, various phosphorescent light emitting materials may be selected and used.

As the TADF material, fullerene and its derivatives, acridine and its derivatives, eosin derivatives and the like can be used. A metal-containing porphyrin containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), palladium (Pd), or the like. Examples of the metal-containing porphyrin include a protoporphyrin-tin fluoride complex (SnF ₂ (Proto IX)), a mesoporphyrin-tin fluoride complex (SnF ₂ (Meso IX)) represented by the following structural formula, and hematoporphyrin. - tin fluoride complex _{(SnF 2 (Hemato IX))} , coproporphyrin tetramethyl ester - tin fluoride complex _{(SnF 2 (Copro III-4Me} )), octaethylporphyrin - tin fluoride complex _(SnF 2 _(OEP)) , Etioporphyrin-tin fluoride complex (SnF ₂ (Etio I)), octaethylporphyrin-platinum chloride complex (PtCl ₂ OEP), and the like.

In addition, 2-biphenyl-4,6-bis (12-phenylindolo [2,3-a] carbazol-11-yl) -1,3,5-triazine (abbreviation: PIC-) represented by the following structural formula TRZ), 9- (4,6-diphenyl-1,3,5-triazin-2-yl) -9′-phenyl-9H, 9′H-3,3′-bicarbazole (abbreviation: PCCzTzn), 9- [4- (4,6-diphenyl-1,3,5-triazin-2-yl) phenyl] -9′-phenyl-9H, 9′H-3,3′-bicarbazole (abbreviation: PCCzPTzn) 2- [4- (10H-phenoxazin-10-yl) phenyl] -4,6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3- [4- (5-phenyl- 5,10-dihydrophenazin-10-yl) fe L] -4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3- (9,9-dimethyl-9H-acridin-10-yl) -9H-xanthen-9-one ( Abbreviation: ACRXTN), bis [4- (9,9-dimethyl-9,10-dihydroacridine) phenyl] sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H, 10′H-spiro [acridine-9, 9′-anthracene] -10′-one (abbreviation: ACRSA) and the like, and heterocyclic compounds having both a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring can also be used. Since the heterocyclic compound has a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring, both the electron transport property and the hole transport property are high, which is preferable. In addition, a substance in which a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring are directly bonded increases both the donor property of the π-electron rich heteroaromatic ring and the acceptor property of the π-electron insufficient heteroaromatic ring. Since the energy difference between the S ₁ level and the T ₁ level is small, it is particularly preferable because thermally activated delayed fluorescence can be obtained efficiently. Instead of the π-electron deficient heteroaromatic ring, an aromatic ring to which an electron withdrawing group such as a cyano group is bonded may be used.

In addition, as the quantum dot, a group 14 element, a group 15 element, a group 16 element, a compound composed of a plurality of group 14 elements, a compound of an element belonging to groups 4 to 14 and a group 16 element A compound of a Group 2 element and a Group 16 element, a compound of a Group 13 element and a Group 15 element, a compound of a Group 13 element and a Group 17 element, a Group 14 element and a Group 15 element, and And compounds of Group 11 elements and Group 17 elements, iron oxides, titanium oxides, chalcogenide spinels, various semiconductor clusters, metal halogen perovskites, and the like.

Specifically, cadmium selenide (CdSe), cadmium sulfide (CdS), cadmium telluride (CdTe), zinc selenide (ZnSe), zinc oxide (ZnO), zinc sulfide (ZnS), zinc telluride (ZnTe) , Mercury sulfide (HgS), mercury selenide (HgSe), mercury telluride (HgTe), indium arsenide (InAs), indium phosphide (InP), gallium arsenide (GaAs), gallium phosphide (GaP), indium nitride ( InN), gallium nitride (GaN), indium antimonide (InSb), gallium antimonide (GaSb), aluminum phosphide (AlP), aluminum arsenide (AlAs), aluminum antimonide (AlSb), lead selenide (II) ( PbSe), lead telluride (II) (PbTe), lead sulfide (I ) (PbS), indium selenide _(In 2 _Se 3), telluride, indium _(In 2 _Te 3), indium sulfide _{(In 2 S} 3), gallium selenide _(Ga 2 _Se 3), arsenic sulfide (III) ( As ₂ S ₃ ), arsenic selenide (III) (As ₂ Se ₃ ), arsenic telluride (III) (As ₂ Te ₃ ), antimony sulfide (III) (Sb ₂ S ₃ ), antimony selenide (III) (Sb ₂ Se ₃ ), antimony telluride (III) (Sb ₂ Te ₃ ), bismuth (III) sulfide (Bi ₂ S ₃ ), bismuth selenide (III) (Bi ₂ Se ₃ ), bismuth telluride (III ) _(Bi 2 _Te 3), silicon (Si), silicon carbide (SiC), germanium (Ge), tin (Sn), selenium (Se), tellurium (Te), boric (B), carbon (C), phosphorus (P), boron nitride (BN), boron phosphide (BP), arsenide boron (BAs), aluminum nitride (AlN), aluminum sulfide _{(Al 2 S} 3), barium sulfide (BaS), barium selenide (BaSe), barium telluride (BaTe), calcium sulfide (CaS), calcium selenide (CaSe), calcium telluride (CaTe), beryllium sulfide (BeS), beryllium selenide (BeSe) , Beryllium telluride (BeTe), magnesium sulfide (MgS), magnesium selenide (MgSe), germanium sulfide (GeS), germanium selenide (GeSe), germanium telluride (GeTe), tin (IV) sulfide (SnS ₂ ) , Tin (II) sulfide (SnS), tin (II) selenide (SnSe) , Tin telluride (SnTe), lead oxide (II) (PbO), copper fluoride (I) (CuF), copper chloride (I) (CuCl), copper bromide (I) (CuBr), iodine Copper (I) (CuI), copper (I) oxide (Cu ₂ O), copper (I) selenide (Cu ₂ Se), nickel (II) oxide (NiO), cobalt (II) oxide (CoO), Cobalt sulfide (II) (CoS), triiron tetroxide (Fe ₃ O ₄ ), iron (II) sulfide (FeS), manganese oxide (II) (MnO), molybdenum sulfide (IV) (MoS ₂ ), vanadium oxide (II) (VO), vanadium oxide (IV) (VO ₂ ), tungsten oxide (IV) (WO ₂ ), tantalum oxide (V) (Ta ₂ O ₅ ), titanium oxide (TiO ₂ , Ti ₂ O ₅ , Ti ₂ O _3, etc. _Ti 5 _{O 9),} oxidation di Koniumu _(ZrO 2), silicon nitride _{(Si 3 N} 4), germanium nitride _{(Ge 3 N} 4), aluminum oxide _{(Al 2 O} 3), barium titanate (BaTiO _3), selenium and zinc compounds and cadmium (CdZnSe ), A compound of indium, arsenic and phosphorus (InAsP), a compound of cadmium, selenium and sulfur (CdSeS), a compound of cadmium, selenium and tellurium (CdSeTe), a compound of indium, gallium and arsenic (InGaAs), indium, gallium and A compound of selenium (InGaSe), a compound of indium, selenium, and sulfur (InSeS), a compound of copper, indium, and sulfur (for example, CuInS ₂ ), and combinations thereof can be exemplified, but not limited thereto. Moreover, you may use what is called an alloy type quantum dot whose composition is represented by arbitrary ratios. For example, an alloy type quantum dot represented by CdS _x Se _1-x (x is an arbitrary number from 0 to 1) can change the emission wavelength by changing the ratio of x, and thus obtains blue light emission. Is one of the effective means.

  The structure of the quantum dot includes a core type, a core-shell type, and a core-multishell type, and any of them may be used, but the shell is covered with another inorganic material that covers the core and has a wider band gap. By forming, the influence of defects and dangling bonds existing on the nanocrystal surface can be reduced. Thereby, in order to greatly improve the quantum efficiency of light emission, it is preferable to use a core-shell type or core-multishell type quantum dot. Examples of the shell material include zinc sulfide (ZnS) and zinc oxide (ZnO).

  In addition, since the quantum dots have a high ratio of surface atoms, they are highly reactive and tend to aggregate. Therefore, it is preferable that a protective agent is attached or a protective group is provided on the surface of the quantum dots. Aggregation can be prevented and solubility in a solvent can be increased by attaching the protective agent or providing a protective group. It is also possible to reduce the reactivity and improve the electrical stability. Examples of the protecting agent (or protecting group) include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, tripropylphosphine, tributylphosphine, trihexylphosphine, Trialkylphosphines such as octylphosphine, polyoxyethylene alkylphenyl ethers such as polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, tri (n-hexyl) amine, tri (n-octyl) Tertiary amines such as amine and tri (n-decyl) amine, tripropylphosphine oxide, tributylphosphine oxide, trihexylphosphine oxide, trioctylphosphite Organic phosphorus compounds such as oxide and tridecylphosphine oxide, polyethylene glycol diesters such as polyethylene glycol dilaurate and polyethylene glycol distearate, and organic nitrogen compounds such as nitrogen-containing aromatic compounds such as pyridine, lutidine, collidine and quinolines , Hexylamine, octylamine, decylamine, dodecylamine, tetradecylamine, hexadecylamine, octadecylamine and other amino alkanes, dibutyl sulfide and other dialkyl sulfides, dimethyl sulfoxide and dibutyl sulfoxide and other dialkyl sulfoxides, and thiophene Organic sulfur compounds such as sulfur-containing aromatic compounds, higher fatty acids such as palmitic acid, stearic acid, oleic acid, alcohols, sorbitan fatty acid esters Fatty acid modified polyesters, tertiary amine modified polyurethanes and polyethylene imines, and the like.

  The quantum dots may be rod-like quantum rods. Since the quantum rod exhibits light having directivity polarized in the c-axis direction, a light-emitting element with better external quantum efficiency can be obtained by using the quantum rod as a light-emitting material.

When forming a light emitting layer in which the quantum dots are dispersed in the host as a light emitting material, the quantum dots are dispersed in the host material, or the host material and the quantum dots are dissolved or dispersed in an appropriate liquid medium. (Spin coating method, casting method, die coating method, blade coating method, roll coating method, ink jet method, printing method, spray coating method, curtain coating method, Langmuir / Blodgett method, etc.) Alternatively, it may be formed by firing.

  Examples of the liquid medium used in the wet process include ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, halogenated hydrocarbons such as dichlorobenzene, and aromatic carbonization such as toluene, xylene, mesitylene, and cyclohexyl benzene. Hydrogen, aliphatic hydrocarbons such as cyclohexane, decalin, and dodecane, and organic solvents such as dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) can be used.

In the case of using a fluorescent substance, 9-phenyl-3- [4- (10-phenyl-9-anthryl) phenyl] -9H-carbazole (abbreviation: PCzPA), 3- [4- (1-naphthyl) -phenyl ] -9-phenyl-9H-carbazole (abbreviation: PCPN), 9- [4- (10-phenyl-9-anthracenyl) phenyl] -9H-carbazole (abbreviation: CzPA), 7- [4- (10-phenyl) -9-anthryl) phenyl] -7H-dibenzo [c, g] carbazole (abbreviation: cgDBCzPA), 6- [3- (9,10-diphenyl-2-anthryl) phenyl] -benzo [b] naphtho [1, 2-d] furan (abbreviation: 2 mBnfPPA), 9-phenyl-10- {4- (9-phenyl-9H-fluoren-9-yl) -biphenyl-4'- Le} anthracene (abbreviation: FLPPA) is suitable material having a anthracene skeleton such as. When a substance having an anthracene skeleton is used as a host material for a fluorescent light-emitting substance, a light-emitting layer with favorable emission efficiency and durability can be realized. In particular, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA are preferable choices because they exhibit very good characteristics.

When a material other than the above materials is used as the host material, various carrier transport materials such as a material having an electron transport property and a material having a hole transport property can be used.

  However, as the host material for the light-emitting layer, it is preferable to use an organic compound including a pyrimidine skeleton having a phenylene group having an alkyl group at the 5-position and a substituent at the 4-position and the 6-position as described above. . Since the organic compound is a substance having a high band gap and a high T1 level, the organic compound can be very preferably used as a host material of a phosphorescent light-emitting element.

The organic compound is an organic compound having a relatively shallow LUMO because the phenylene group is twisted when an alkyl group is bonded to the 5-position. Further, since the T1 level is also increased, it is suitable for use as a host material particularly when a green to blue phosphorescent substance is used.

Here, the organic compound will be described in more detail. The organic compound can also be expressed as an organic compound having a molecular weight of 3000 or less represented by the following general formula (G1).

However, in General Formula (G1), R ¹ represents any one of an alkyl group having 1 to 6 carbon atoms, and each of the carbon atoms at positions A and B has a substituent.

Alternatively, the organic compound is an organic compound having a skeleton represented by the following general formula (G1) and having a molecular weight of 3000 or less.

However, in General Formula (G1), R ¹ represents any one of an alkyl group having 1 to 6 carbon atoms, and each of the carbon atoms at positions A and B has a carbazole skeleton, a fluorene skeleton, a dibenzothiophene skeleton, and a dibenzofuran skeleton. It has a substituent containing any one skeleton.

Moreover, the said organic compound can also be represented as follows.

However, in General Formula (G1), R ¹ represents any one of an alkyl group having 1 to 6 carbon atoms, and is independently represented by the following General Formula (G2-1) or ( The group represented by G2-2) is bonded.

However, in General Formula (G2-1), X ¹ represents any ^one of a nitrogen atom, an oxygen atom, a sulfur atom, and a carbon atom. When X ¹ is a nitrogen atom or a carbon atom, the nitrogen atom may have one and the carbon atom may have one or two substituents. R ^{11 to} R ¹⁸ each independently represents any one of hydrogen and an alkyl group having 1 to 6 carbon atoms. Note that one of R ^{11 to} R ¹⁴ may be a bond, and when X ¹ is nitrogen, the position of A in the general formula (G1) depends on any one of the bonds of the nitrogen. Or carbon at the B position.

However, in General Formula (G2-2), X ² represents any one of a nitrogen atom, an oxygen atom, a sulfur atom, and a carbon atom. When X ² is a nitrogen atom or a carbon atom, the nitrogen atom may have one substituent and the carbon atom may have one or two substituents. R ^{21 to} R ²⁸ each independently represents any one of hydrogen and an alkyl group having 1 to 6 carbon atoms. Note that one of R ^{21 to} R ²⁴ may be a bond, and in the case where the bond or X ² is nitrogen, one of the bonds of nitrogen has a bond of A in General Formula (G1). Bonds to carbon at position B or carbon at position B. In addition, α and β represent a ring condensed with two adjacent rings, α represents a ring represented by the following general formula (G3), and β represents a ring represented by the following general formula (G4).

The ring represented by the general formula (G3) is fused with two adjacent rings at the position of ac or the position of ad in the formula (G3). R ³¹ and R ³² each independently represent hydrogen or any one of an alkyl group having 1 to 6 carbon atoms.

The ring represented by the general formula (G4) is condensed with two adjacent rings at the position bd in the formula (G4). X ³ represents any one of a nitrogen atom, an oxygen atom, a sulfur atom, and a carbon atom. When X ³ is a nitrogen atom or a carbon atom, the nitrogen atom may have one substituent, and the carbon atom may have one or two substituents.

Note that in the organic compound represented by the general formula (G1), the group having a carbazole skeleton substituted with A or B is preferably a group represented by the general formula (G2-1).

In addition, the groups having a carbazole skeleton substituted for A or B are preferably the same group from the viewpoint of ease of synthesis.

X ¹ is preferably nitrogen. In that case, it is preferable that the nitrogen of X1 is bonded to the carbon at the position A or the carbon at the position B in the general formula (G1).

That is, an organic compound represented by the following general formula (G5) is preferable.

However, in the formula represented by the general formula (G5), R ¹ represents an alkyl group having 1 to 6 carbon atoms, and R ^{41 to} R ⁴⁸ and R ^{51 to} R ⁵⁸ are each independently hydrogen or 1 to C carbon atoms. Represents any one of 6 alkyl groups;

In addition, when the atom of X1 is any of a sulfur atom, an oxygen atom, and a carbon atom, the group represented by General Formula (G2-1) is the position of R ^{18 and} the group represented by A or B in General Formula (G1) It is preferably bonded to the carbon atom at the position.

That is, an organic compound represented by the following general formula (G6) is preferable.

Note that in the formula represented by the general formula (G6), R ¹ represents an alkyl group having 1 to 6 carbon atoms, and R ^{61 to} R ⁶⁷ and R ^{71 to} R ⁷⁷ are each independently hydrogen or 1 to C carbon atoms. Represents any one of 6 alkyl groups;

Among these, organic compounds represented by the following general formulas (G7) to (G10) are preferable because they can be easily synthesized.

However, in the organic compounds represented by the general formulas (G7) to (G10), R ¹ represents an alkyl group having 1 to 6 carbon atoms.

In the organic compound represented by the general formula (G1), the group having a carbazole skeleton substituted on the carbon atom at the position A or B is a group represented by the general formula (G2-2). preferable. In addition, it is preferable that the group having a carbazole skeleton substituted on both of the carbon atoms at the position A or B is a group represented by the above general formula (G2-2) from the viewpoint of ease of synthesis. Incidentally, at least one of the group represented in X ² in this case general formula (G2-2), it is preferred that both preferably are nitrogen atoms. Further, the nitrogen of X ² is preferably bonded to carbons at positions A and B in the general formula (G1).

Specific examples of the organic compounds represented by the above general formulas (G1) to (G10) are shown below.

Since these organic compounds have electron transport properties, when used in a light-emitting element that uses an exciplex of a plurality of host materials as described later for energy transfer to a light-emitting substance, the material having an electron transport property is used. It can be used as one.

In addition, materials that can be used as a host material in the light-emitting layer are shown below.

As a material having an electron transporting property, for example, bis (10-hydroxybenzo [h] quinolinato) beryllium (II) (abbreviation: BeBq ₂ ), bis (2-methyl-8-quinolinolato) (4-phenylphenolato) Aluminum (III) (abbreviation: BAlq), bis (8-quinolinolato) zinc (II) (abbreviation: Znq), bis [2- (2-benzoxazolyl) phenolato] zinc (II) (abbreviation: ZnPBO), Metal complexes such as bis [2- (2-benzothiazolyl) phenolato] zinc (II) (abbreviation: ZnBTZ), 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4 -Oxadiazole (abbreviation: PBD), 3- (4-biphenylyl) -4-phenyl-5- (4-tert-butylphenyl) -1,2,4-to Azole (abbreviation: TAZ), 1,3-bis [5- (p-tert-butylphenyl) -1,3,4-oxadiazol-2-yl] benzene (abbreviation: OXD-7), 9- [ 4- (5-phenyl-1,3,4-oxadiazol-2-yl) phenyl] -9H-carbazole (abbreviation: CO11), 2,2 ′, 2 ″-(1,3,5-benzene Triyl) tris (1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2- [3- (dibenzothiophen-4-yl) phenyl] -1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II) ) And other heterocyclic compounds having a polyazole skeleton, 2- [3- (dibenzothiophen-4-yl) phenyl] dibenzo [f, h] quinoxaline (abbreviation: 2mDBTPDBq-II), 2 -[3 '-(Dibenzothiophen-4-yl) biphenyl-3-yl] dibenzo [f, h] quinoxaline (abbreviation: 2mDBTBPDBq-II), 2- [3'-(9H-carbazol-9-yl) biphenyl -3-yl] dibenzo [f, h] quinoxaline (abbreviation: 2mCzBPDBq), 4,6-bis [3- (phenanthrene-9-yl) phenyl] pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis [ Heterocyclic compounds having a diazine skeleton such as 3- (4-dibenzothienyl) phenyl] pyrimidine (abbreviation: 4,6mDBTP2Pm-II) and 3,5-bis [3- (9H-carbazol-9-yl) phenyl] Pyridine (abbreviation: 35DCzPPy), 1,3,5-tri [3- (3-pyridyl) phenyl] benzene (abbreviation: TmPyP) ) Heterocyclic compounds having a pyridine skeleton such. Among the compounds described above, a heterocyclic compound having a diazine skeleton and a heterocyclic compound having a pyridine skeleton are preferable because of their good reliability. In particular, a heterocyclic compound having a diazine (pyrimidine or pyrazine) skeleton has a high electron transporting property and contributes to a reduction in driving voltage.

  As a material having a hole transporting property, 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: NPB), N, N′-bis (3-methylphenyl)- N, N′-diphenyl- [1,1′-biphenyl] -4,4′-diamine (abbreviation: TPD), 4,4′-bis [N- (spiro-9,9′-bifluoren-2-yl) ) -N-phenylamino] biphenyl (abbreviation: BSPB), 4-phenyl-4 '-(9-phenylfluoren-9-yl) triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9- Phenylfluoren-9-yl) triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4 ′-(9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBA1BP), 4 4′-diphenyl-4 ″-(9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBBi1BP), 4- (1-naphthyl) -4 ′-(9-phenyl-9H-carbazole) -3-yl) triphenylamine (abbreviation: PCBBANB), 4,4′-di (1-naphthyl) -4 ″-(9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBNBB) ), 9,9-dimethyl-N-phenyl-N- [4- (9-phenyl-9H-carbazol-3-yl) phenyl] fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N- [ Aromatic amines such as 4- (9-phenyl-9H-carbazol-3-yl) phenyl] spiro-9,9′-bifluoren-2-amine (abbreviation: PCBASF) Compounds having a rating, 1,3-bis (N-carbazolyl) benzene (abbreviation: mCP), 4,4′-di (N-carbazolyl) biphenyl (abbreviation: CBP), 3,6-bis (3,5 -Diphenylphenyl) -9-phenylcarbazole (abbreviation: CzTP), 3,3′-bis (9-phenyl-9H-carbazole) (abbreviation: PCCP) and other compounds having a carbazole skeleton, and 4,4 ′, 4 ''-(Benzene-1,3,5-triyl) tri (dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4- [4- (9-phenyl-9H-fluoren-9-yl) ) Phenyl] dibenzothiophene (abbreviation: DBTFLP-III), 4- [4- (9-phenyl-9H-fluoren-9-yl) phenyl] -6-phenyldibenzothiop A compound having a thiophene skeleton such as phen (abbreviation: DBTFLP-IV), 4,4 ′, 4 ″-(benzene-1,3,5-triyl) tri (dibenzofuran) (abbreviation: DBF3P-II), And a compound having a furan skeleton such as 4- {3- [3- (9-phenyl-9H-fluoren-9-yl) phenyl] phenyl} dibenzofuran (abbreviation: mmDBFFLBi-II). Among the compounds described above, a compound having an aromatic amine skeleton and a compound having a carbazole skeleton are preferable because they have good reliability, high hole transportability, and contribute to reduction in driving voltage. In addition to the hole transport material described above, a hole transport material may be used from various substances.

  In the case where a fluorescent substance is used as the luminescent substance, 9-phenyl-3- [4- (10-phenyl-9-anthryl) phenyl] -9H-carbazole (abbreviation: PCzPA), 3- [4- (1-naphthyl) is used. ) -Phenyl] -9-phenyl-9H-carbazole (abbreviation: PCPN), 9- [4- (10-phenyl-9-anthracenyl) phenyl] -9H-carbazole (abbreviation: CzPA), 7- [4- ( 10-phenyl-9-anthryl) phenyl] -7H-dibenzo [c, g] carbazole (abbreviation: cgDBCzPA), 6- [3- (9,10-diphenyl-2-anthryl) phenyl] -benzo [b] naphtho [1,2-d] furan (abbreviation: 2 mBnfPPA), 9-phenyl-10- {4- (9-phenyl-9H-fluoren-9-yl) -bif Sulfonyl-4'-yl} - anthracene (abbreviation: FLPPA) is suitable material having a anthracene skeleton such as. When a substance having an anthracene skeleton is used as a host material for a fluorescent light-emitting substance, a light-emitting layer with favorable emission efficiency and durability can be realized. In particular, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA are preferable choices because they exhibit very good characteristics.

  Note that the host material may be a material in which a plurality of types of substances are mixed. When a mixed host material is used, it is preferable to mix a material having an electron transporting property and a material having a hole transporting property. . By mixing a material having an electron transporting property and a material having a hole transporting property, the transportability of the light-emitting layer 113 can be easily adjusted, and the recombination region can be easily controlled. The ratio of the content of the hole transporting material and the electron transporting material may be set to 1: 9 to 9: 1.

  Moreover, you may form an exciplex with these mixed host materials. By selecting a combination that forms an exciplex that emits light that overlaps with the wavelength of the absorption band on the lowest energy side of the fluorescent light-emitting substance, the phosphorescent light-emitting substance, and the TADF material, energy transfer can be performed. Smooth and efficient light emission can be obtained. Further, this structure is a preferable structure because the driving voltage is also reduced.

  The light emitting layer 113 having the above-described configuration is manufactured by co-evaporation using a vacuum evaporation method or a mixed solution using a gravure printing method, an offset printing method, an ink jet method, a spin coating method, a dip coating method, or the like. Can do.

  The electron-transporting layer 114 is a layer containing a substance having an electron-transporting property, and examples of the substance having an electron-transporting property include the materials mentioned as the materials having an electron-transporting property that can be used for the host material, and an anthracene skeleton. The material which has can be used.

  Further, a layer for controlling the movement of electron carriers may be provided between the electron transport layer and the light emitting layer. This is a layer obtained by adding a small amount of a substance having a high electron trapping property to a material having a high electron transporting property as described above. By suppressing the movement of electron carriers, the carrier balance can be adjusted. Such a configuration is very effective in suppressing problems that occur when electrons penetrate through the light emitting layer (for example, a reduction in device lifetime).

Further, an electron injection layer 115 may be provided between the electron transport layer 114 and the cathode 102 in contact with the cathode 102. As the electron injection layer 115, an alkali metal or an alkaline earth metal such as lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF ₂ ), or a compound thereof can be used. For example, a layer made of a substance having an electron transporting property containing an alkali metal, an alkaline earth metal, or a compound thereof can be used. Further, electride may be used for the electron injection layer 115. Examples of the electride include a substance obtained by adding a high concentration of electrons to a mixed oxide of calcium and aluminum. Note that it is more preferable to use an electron-injecting layer 115 in which an alkali metal or an alkaline earth metal is contained in a layer made of a substance having an electron-transporting property because electron injection from the cathode 102 is efficiently performed. .

  Further, a charge generation layer 116 may be provided instead of the electron injection layer 115 (FIG. 3B). The charge generation layer 116 is a layer that can inject holes into a layer in contact with the cathode side of the layer and inject electrons into a layer in contact with the anode side by applying a potential. The charge generation layer 116 includes at least a P-type layer 117. The P-type layer 117 is preferably formed using the composite material mentioned as the material that can form the hole injection layer 111 described above. Further, the P-type layer 117 may be formed by stacking the above-described film containing an acceptor material and a film containing a hole transport material as a material constituting the composite material. By applying a potential to the P-type layer 117, electrons are injected into the electron transport layer 114 and holes are injected into the cathode 102, which is a cathode, and the light emitting element operates. At this time, the presence of the layer containing the organic compound of one embodiment of the present invention at a position in contact with the charge generation layer 116 of the electron transport layer 114 suppresses a decrease in luminance due to accumulation of driving time of the light-emitting element, thereby reducing the lifetime. A long light emitting element can be obtained.

  The charge generation layer 116 is preferably provided with one or both of an electron relay layer 118 and an electron injection buffer layer 119 in addition to the P-type layer 117.

The electron relay layer 118 includes at least a substance having an electron transporting property, and has a function of smoothly transferring electrons by preventing the interaction between the electron injection buffer layer 119 and the P-type layer 117. The LUMO level of the substance having an electron transporting property contained in the electron relay layer 118 is the LUMO level of the acceptor substance in the P-type layer 117 and the substance contained in the layer in contact with the charge generation layer 116 in the electron transporting layer 114. It is preferably between the LUMO levels. The specific energy level of the LUMO level in the substance having an electron transporting property used for the electron relay layer 118 is −5.0 eV or more, preferably −5.0 eV or more and −3.0 eV or less. Note that as the substance having an electron transporting property used for the electron relay layer 118, a phthalocyanine-based material or a metal complex having a metal-oxygen bond and an aromatic ligand is preferably used.

  The electron injection buffer layer 119 includes an alkali metal, an alkaline earth metal, a rare earth metal, and a compound thereof (including an alkali metal compound (including an oxide such as lithium oxide, a halide, and a carbonate such as lithium carbonate and cesium carbonate). , Alkaline earth metal compounds (including oxides, halides, carbonates) or rare earth metal compounds (including oxides, halides, carbonates) can be used. It is.

  In the case where the electron injection buffer layer 119 is formed to include an electron transporting substance and a donor substance, an alkali metal, an alkaline earth metal, a rare earth metal, or a compound thereof (as a donor substance) Alkali metal compounds (including oxides such as lithium oxide, halides, carbonates such as lithium carbonate and cesium carbonate), alkaline earth metal compounds (including oxides, halides, carbonates), or rare earth metal compounds In addition to (including oxides, halides, and carbonates), organic compounds such as tetrathianaphthacene (abbreviation: TTN), nickelocene, and decamethyl nickelocene can also be used. Note that the substance having an electron transporting property can be formed using a material similar to the material of the electron transport layer 114 described above.

  As a material for forming the cathode 102, 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 cathode materials include alkali metals such as lithium (Li) and cesium (Cs), and group 1 of the periodic table of elements such as magnesium (Mg), calcium (Ca), and strontium (Sr) Examples include elements belonging to Group 2, and alloys containing these (MgAg, AlLi), europium (Eu), ytterbium (Yb), and other rare earth metals, and alloys containing these. However, by providing an electron injection layer between the cathode 102 and the electron transport layer, various types such as indium oxide-tin oxide containing Al, Ag, ITO, silicon, or silicon oxide can be used regardless of the work function. A conductive material can be used as the cathode 102. These conductive materials can be formed by a dry method such as a vacuum evaporation method or a sputtering method, an inkjet method, a spin coating method, or the like. Alternatively, a sol-gel method may be used for a wet method, or a metal material paste may be used for a wet method.

Various methods can be used for forming the EL layer 103 regardless of a dry method or a wet method. For example, vacuum deposition method, wet process method (spin coating method, casting method, die coating method, blade coating method, roll coating method, ink jet method, printing method (gravure printing method, offset printing method, screen printing method, etc.), spray coating Method, curtain coating method, Langmuir / Blodgett method, etc.).

  Further, each electrode or each layer described above may be formed by using different film forming methods.

  Here, a method for forming the EL layer 786 using a droplet discharge method will be described with reference to FIGS. 2A to 2D are cross-sectional views illustrating a method for manufacturing the EL layer 786.

  First, the conductive film 772 is formed over the planarization insulating film 770, and the insulating film 730 is formed so as to cover part of the conductive film 772 (see FIG. 2A).

  Next, a droplet 784 is discharged from a droplet discharge device 783 to an exposed portion of the conductive film 772 which is an opening of the insulating film 730, so that a layer 785 containing a composition is formed. The droplet 784 is a composition containing a solvent and adheres to the conductive film 772 (see FIG. 2B).

  Note that the step of discharging the droplet 784 may be performed under reduced pressure.

  Next, an EL layer 786 is formed by removing the solvent from the layer 785 containing the composition and solidifying the layer (see FIG. 2C).

  Note that as a method for removing the solvent, a drying step or a heating step may be performed.

  Next, a conductive film 788 is formed over the EL layer 786, so that the light-emitting element 782 is formed (see FIG. 2D).

  In this manner, when the EL layer 786 is formed by a droplet discharge method, a composition can be selectively discharged, so that loss of materials can be reduced. In addition, since a lithography process or the like for processing the shape is not necessary, the process can be simplified and cost reduction can be achieved.

  The droplet discharge method described above is a general term for a device having means for discharging droplets such as a nozzle having a composition discharge port or a head having one or a plurality of nozzles.

  Next, a droplet discharge apparatus used for the droplet discharge method will be described with reference to FIG. FIG. 3 is a conceptual diagram illustrating the droplet discharge device 1400.

  The droplet discharge device 1400 includes a droplet discharge unit 1403. The droplet discharge unit 1403 includes a head 1405, a head 1412, and a head 1416.

  The head 1405 and the head 1412 are connected to the control means 1407, and can be drawn in a pre-programmed pattern under the control of the computer 1410.

  In addition, the drawing timing may be performed based on, for example, the marker 1411 formed on the substrate 1402. Alternatively, the reference point may be determined based on the outer edge of the substrate 1402. Here, the marker 1411 is detected by the image pickup means 1404, the digital signal converted by the image processing means 1409 is recognized by the computer 1410, a control signal is generated and sent to the control means 1407.

  As the imaging unit 1404, an image sensor using a charge coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS) can be used. Information on the pattern to be formed on the substrate 1402 is stored in the storage medium 1408. Based on this information, a control signal is sent to the control means 1407, and the individual heads 1405 of the droplet discharge means 1403 are sent. The head 1412 and the head 1416 can be individually controlled. The material to be discharged is supplied from a material supply source 1413, a material supply source 1414, and a material supply source 1415 to a head 1405, a head 1412, and a head 1416 through piping.

  The inside of the head 1405, the head 1412, and the head 1416 has a structure having a space filled with a liquid material and a nozzle that is a discharge port as indicated by a dotted line 1406. Although not shown, the head 1412 has the same internal structure as the head 1405. When the nozzles of the head 1405 and the head 1412 are provided in different sizes, different materials can be drawn simultaneously with different widths. A single head can discharge and draw multiple types of light emitting materials, and when drawing over a wide area, the same material can be simultaneously discharged and drawn from multiple nozzles to improve throughput. it can. When a large substrate is used, the head 1405, the head 1412, and the head 1416 can freely scan the substrate in the directions of arrows X, Y, and Z shown in FIG. A plurality of the same patterns can be drawn on one substrate.

  The step of discharging the composition may be performed under reduced pressure. The substrate may be heated at the time of discharge. After discharging the composition, one or both steps of drying and baking are performed. The drying and firing steps are both heat treatment steps, but their purpose, temperature and time are different. The drying process and the firing process are performed under normal pressure or reduced pressure by laser light irradiation, rapid thermal annealing, a heating furnace, or the like. Note that the timing of performing this heat treatment and the number of heat treatments are not particularly limited. In order to satisfactorily perform the drying and firing steps, the temperature at that time depends on the material of the substrate and the properties of the composition.

  As described above, the EL layer 786 can be manufactured using a droplet discharge apparatus.

In the case of forming the EL layer 786 using a droplet discharge device, when a wet method is used to form a composition in which various organic materials or organic inorganic halogen perovskites are dissolved or dispersed in a solvent, various organic solvents are used. It can be set as the composition for application | coating. Examples of the organic solvent that can be used in the composition include benzene, toluene, xylene, mesitylene, tetrahydrofuran, dioxane, ethanol, methanol, n-propanol, isopropanol, n-butanol, t-butanol, acetonitrile, dimethyl sulfoxide, and dimethylformamide. Various organic solvents such as chloroform, methylene chloride, carbon tetrachloride, ethyl acetate, hexane, and cyclohexane can be used. In particular, by using a low-polarity benzene derivative such as benzene, toluene, xylene, or mesitylene, a solution having a suitable concentration can be prepared, and the material contained in the ink can be prevented from being deteriorated due to oxidation or the like. Therefore, it is preferable. In consideration of the uniformity of the film after fabrication and the uniformity of the film thickness, the boiling point is preferably 100 ° C. or higher, and toluene, xylene, and mesitylene are more preferable.

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

  Next, an embodiment of a light-emitting element having a structure in which a plurality of light-emitting units is stacked (also referred to as a stacked element) is described with reference to FIG. This light emitting element is a light emitting element having a plurality of light emitting units between an anode and a cathode. One light-emitting unit has a structure similar to that of the EL layer 103 illustrated in FIG. That is, the light-emitting element illustrated in FIG. 1A or 1B is a light-emitting element having one light-emitting unit, and the light-emitting element illustrated in FIG. 1C is a light-emitting element having a plurality of light-emitting units. It can be said that.

  In FIG. 1C, a first light-emitting unit 511 and a second light-emitting unit 512 are stacked between an anode 501 and a cathode 502, and the first light-emitting unit 511 and the second light-emitting unit 512 are stacked. A charge generation layer 513 is provided between the two. The anode 501 and the cathode 502 correspond to the anode 101 and the cathode 102 in FIG. 1A, respectively, and the same materials as those described in the description of FIG. Further, the first light emitting unit 511 and the second light emitting unit 512 may have the same configuration or different configurations.

  The charge generation layer 513 has a function of injecting electrons into one light-emitting unit and injecting holes into the other light-emitting unit when a voltage is applied to the anode 501 and the cathode 502. That is, in FIG. 1C, when a voltage is applied so that the potential of the anode is higher than the potential of the cathode, the charge generation layer 513 injects electrons into the first light-emitting unit 511, and the second What is necessary is just to inject holes into the light emitting unit 512.

  The charge generation layer 513 is preferably formed with a structure similar to that of the charge generation layer 116 described with reference to FIG. Since the composite material of an organic compound and a metal oxide is excellent in carrier injecting property and carrier transporting property, low voltage driving and low current driving can be realized. Note that in the case where the surface of the light emitting unit on the anode side is in contact with the charge generation layer 513, the charge generation layer 513 can also serve as a hole injection layer of the light emission unit. It does not have to be provided.

  Further, in the case where the electron injection buffer layer 119 is provided in the charge generation layer 513, the layer plays a role of the electron injection buffer layer in the light emitting unit on the anode side. Therefore, it is necessary to form the electron injection layer over the light emitting unit. There is no.

  Although FIG. 1C illustrates a light-emitting element having two light-emitting units, the present invention can be similarly applied to a light-emitting element in which three or more light-emitting units are stacked. Like the light-emitting element according to this embodiment, a plurality of light-emitting units are partitioned and arranged between the pair of electrodes by the charge generation layer 513, thereby enabling high-luminance light emission while keeping the current density low. A long-life device can be realized. In addition, a light-emitting device that can be driven at a low voltage and has low power consumption can be realized.

  Further, by making the light emission colors of the respective light emitting units different, light emission of a desired color can be obtained as the whole light emitting element.

(Embodiment 2)
In this embodiment, a light-emitting device using the light-emitting element described in Embodiment 1 will be described.

  A light-emitting device of one embodiment of the present invention is described with reference to FIGS. 4A is a top view illustrating the light-emitting device, and FIG. 4B is a cross-sectional view taken along lines AB and CD of FIG. 4A. This light-emitting device includes a drive circuit portion (source line drive circuit) 601, a pixel portion 602, and a drive circuit portion (gate line drive circuit) 603 indicated by dotted lines, which control light emission of the light-emitting elements. 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 lead wiring 608 is a wiring for transmitting a signal input to the source line driver circuit 601 and the gate line driver 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 is described with reference to FIG. A driver circuit portion and a pixel portion are formed over the element substrate 610. Here, a source line driver circuit 601 that is a driver circuit portion and one pixel in the pixel portion 602 are illustrated.

  Note that the source line driver circuit 601 is a CMOS circuit in which an n-channel FET 623 and a p-channel FET 624 are combined. The drive circuit may be formed of various CMOS circuits, PMOS circuits, or NMOS circuits. In this embodiment mode, a driver integrated type in which a driver circuit is formed over a substrate is shown; however, this is not necessarily required, and the driver circuit can be formed outside the substrate.

  Further, the pixel portion 602 is formed by a plurality of pixels including a switching FET 611, a current control FET 612, and an anode 613 electrically connected to the drain thereof, but is not limited thereto. The pixel portion may be a combination of an FET and a capacitor.

  The type and crystallinity of the semiconductor used for the FET are not particularly limited, and an amorphous semiconductor or a crystalline semiconductor may be used. As an example of a semiconductor used for an FET, a Group 13 semiconductor, a Group 14 semiconductor, a semiconductor, a compound semiconductor, an oxide semiconductor, or an organic semiconductor material can be used, but an oxide semiconductor is particularly preferable. Examples of the oxide semiconductor include In—Ga oxide and In—M—Zn oxide (M is Al, Ga, Y, Zr, La, Ce, or Nd). Note that the use of an oxide semiconductor material with an energy gap of 2 eV or more, preferably 2.5 eV or more, more preferably 3 eV or more can reduce the off-state current of the transistor, which is a preferable structure.

  Note that an insulator 614 is formed so as to cover an end portion of the anode 613. Here, a positive photosensitive acrylic resin film can be 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, in the case where 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 photosensitive resin or a positive photosensitive resin can be used.

  An EL layer 616 and a cathode 617 are formed on the anode 613. These correspond to the anode 101, the EL layer 103, and the cathode 102 described with reference to FIG. 1A, or the anode 501, the EL layer 503, and the cathode 502 described with reference to FIG.

  The EL layer 616 preferably contains an organometallic complex. The organometallic complex is preferably used as an emission center substance in the emission layer.

  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). When a recess is formed in the sealing substrate and a desiccant is provided therein, deterioration due to the influence of moisture can be suppressed, which is a preferable configuration.

  It is preferable to use an epoxy resin or glass frit for the sealant 605. Moreover, it is desirable that these materials are materials that do not transmit moisture and oxygen as much as possible. As a material used for the element substrate 610 and the sealing substrate 604, a glass substrate or a quartz substrate, or a plastic substrate made of FRP (Fiber Reinforced Plastics), PVF (polyvinyl fluoride), polyester, acrylic, or the like can be used.

  For example, in this specification and the like, transistors and light-emitting elements can be formed using various substrates. The kind of board | substrate is not limited to a specific thing. Examples of the substrate include a semiconductor substrate (for example, a single crystal substrate or a silicon substrate), an SOI substrate, a glass substrate, a quartz substrate, a plastic substrate, a metal substrate, a stainless steel substrate, a substrate having stainless steel foil, and a tungsten substrate. , A substrate having a tungsten foil, a flexible substrate, a laminated film, a paper containing a fibrous material, or a base film. Examples of the glass substrate include barium borosilicate glass, aluminoborosilicate glass, and soda lime glass. Examples of the flexible substrate, the laminated film, and the base film include the following. For example, there are plastics represented by polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polyethersulfone (PES). Another example is a synthetic resin such as acrylic. Alternatively, examples include polytetrafluoroethylene (PTFE), polypropylene, polyester, polyvinyl fluoride, and polyvinyl chloride. As an example, there are polyamide, polyimide, aramid, epoxy, an inorganic vapor deposition film, papers, and the like. In particular, by manufacturing a transistor using a semiconductor substrate, a single crystal substrate, an SOI substrate, or the like, a transistor with small variation in characteristics, size, or shape, high current capability, and small size can be manufactured. . When a circuit is formed using such transistors, the power consumption of the circuit can be reduced or the circuit can be highly integrated.

  Alternatively, a flexible substrate may be used as a substrate, and a transistor or a light-emitting element may be formed directly over the flexible substrate. Alternatively, a separation layer may be provided between the substrate and the transistor or between the substrate and the light-emitting element. The separation layer can be used to separate a semiconductor device from another substrate and transfer it to another substrate after a semiconductor device is partially or entirely completed thereon. At that time, the transistor can be transferred to a substrate having poor heat resistance or a flexible substrate. Note that, for example, a structure of a laminated structure of an inorganic film of a tungsten film and a silicon oxide film or a structure in which an organic resin film such as polyimide is formed over a substrate can be used for the above-described release layer.

That is, a transistor or a light-emitting element may be formed using a certain substrate, and then the transistor or the light-emitting element may be transferred to another substrate, and the transistor or the light-emitting element may be disposed on another substrate. Examples of substrates on which transistors and light-emitting elements are transferred include paper substrates, cellophane substrates, aramid film substrates, polyimide film substrates, stone substrates, wood substrates, and cloth substrates in addition to the above-described substrates on which transistors can be formed. (Natural fibers (silk, cotton, hemp), synthetic fibers (nylon, polyurethane, polyester) or recycled fibers (including acetate, cupra, rayon, recycled polyester), leather substrate, rubber substrate, etc.). By using these substrates, it is possible to form a transistor with good characteristics, a transistor with low power consumption, manufacture a device that is not easily broken, impart heat resistance, reduce weight, or reduce thickness.

  FIG. 5 shows an example of a light-emitting device in which a light-emitting element that emits white light is formed and a full color is obtained by providing a colored layer (color filter) or the like. FIG. 5A shows a substrate 1001, a base insulating film 1002, a gate insulating film 1003, gate electrodes 1006, 1007, and 1008, a first interlayer insulating film 1020, a second interlayer insulating film 1021, a peripheral portion 1042, and a pixel portion. 1040, a driver circuit portion 1041, light-emitting element anodes 1024W, 1024R, 1024G, and 1024B, a partition wall 1025, an EL layer 1028, a light-emitting element cathode 1029, a sealing substrate 1031, a sealant 1032, and the like are illustrated.

  In FIG. 5A, colored layers (a red colored layer 1034R, a green colored layer 1034G, and a blue colored layer 1034B) are provided over a transparent base material 1033. Further, a black layer (black matrix) 1035 may be further provided. The transparent base material 1033 provided with the coloring layer and the black layer is aligned and fixed to the substrate 1001. The colored layer and the black layer are covered with an overcoat layer. In FIG. 5A, there are a light emitting layer in which light is emitted outside without passing through the colored layer, and a light emitting layer in which light is emitted through the colored layer of each color and is transmitted through the colored layer. Since the light that does not pass is white, and the light that passes through the colored layer is red, blue, and green, an image can be expressed by pixels of four colors.

  FIG. 5B illustrates an example in which a colored layer (a red colored layer 1034R, a green colored layer 1034G, or a blue colored layer 1034B) is formed between the gate insulating film 1003 and the first interlayer insulating film 1020. . As described above, the coloring layer may be provided between the substrate 1001 and the sealing substrate 1031.

  In the light-emitting device described above, a light-emitting device having a structure in which light is extracted to the substrate 1001 side where the FET is formed (bottom emission type) is used. However, a structure in which light is extracted to the sealing substrate 1031 side (top-emission type). ). A cross-sectional view of a top emission type light emitting device is shown in FIG. In this case, a substrate that does not transmit light can be used as the substrate 1001. Until the connection electrode for connecting the FET and the anode of the light emitting element is manufactured, it is formed in the same manner as the bottom emission type light emitting device. Thereafter, a third interlayer insulating film 1037 is formed so as to cover the electrode 1022. This insulating film may play a role of planarization. The third interlayer insulating film 1037 can be formed using various other materials in addition to the same material as the second interlayer insulating film.

  The anodes 1024W, 1024R, 1024G, and 1024B of the light emitting elements are anodes here, but may be cathodes. In the case of a top emission type light emitting device as shown in FIG. 6, the anode is preferably a reflective electrode. The EL layer 1028 has a structure as described for the EL layer 103 in FIG. 1A or the EL layer 503 in FIG. 1B and has an element structure in which white light emission can be obtained.

  In the top emission structure as shown in FIG. 6, sealing can be performed with a sealing substrate 1031 provided with colored layers (red colored layer 1034R, green colored layer 1034G, and blue colored layer 1034B). A black layer (black matrix) 1035 may be provided on the sealing substrate 1031 so as to be positioned between the pixels. The colored layer (red colored layer 1034R, green colored layer 1034G, blue colored layer 1034B) or black layer may be covered with an overcoat layer. Note that the sealing substrate 1031 is a light-transmitting substrate.

  In addition, although an example in which full-color display is performed with four colors of red, green, blue, and white is shown here, there is no particular limitation, and full-color is displayed with three colors of red, green, and blue and four colors of red, green, blue, and yellow. Display may be performed.

  FIG. 7 illustrates a passive matrix light-emitting device which is one embodiment of the present invention. 7A is a perspective view illustrating the light-emitting device, and FIG. 7B is a cross-sectional view taken along line XY in FIG. 7A. In FIG. 7, an EL layer 955 is provided between the electrode 952 and the electrode 956 on 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.

  Since the light-emitting device described above can control a large number of minute light-emitting elements arranged in a matrix with FETs formed in a pixel portion, it is suitable as a display device that expresses an image. It is a light emitting device that can be used.

≪Lighting device≫
An illumination device which is one embodiment of the present invention will be described with reference to FIG. 8B is a top view of the lighting device, and FIG. 8A is a cross-sectional view taken along line ef in FIG. 8B.

  In the lighting device, an anode 401 is formed over a light-transmitting substrate 400 which is a support. The anode 401 corresponds to the anode 101 in FIGS. In the case where light emission is extracted from the anode 401 side, the anode 401 is formed using a light-transmitting material.

  A pad 412 for supplying a voltage to the cathode 404 is formed on the substrate 400.

  An EL layer 403 is formed on the anode 401. The EL layer 403 corresponds to the EL layer 103 or the EL layer 503 in FIGS. For these configurations, refer to the description.

  A cathode 404 is formed so as to cover the EL layer 403. The cathode 404 corresponds to the cathode 102 in FIG. In the case where light emission is extracted from the anode 401 side, the cathode 404 is formed including a material having high reflectance. A voltage is supplied to the cathode 404 by connecting to the pad 412.

  A light emitting element is formed by the anode 401, the EL layer 403, and the cathode 404. The lighting device is completed by fixing the light-emitting element to the sealing substrate 407 using the sealing materials 405 and 406 and sealing the light-emitting element. Either one of the sealing materials 405 and 406 may be used. In addition, a desiccant can be mixed in the inner sealing material 406 (not shown in FIG. 8B), so that moisture can be adsorbed and reliability can be improved.

  Further, by providing a part of the pad 412 and the anode 401 extending outside the sealing materials 405 and 406, an external input terminal can be obtained. Further, an IC chip 420 mounted with a converter or the like may be provided thereon.

≪Electronic equipment≫
Examples of electronic devices that are embodiments of the present invention will be described. As an electronic device, for example, a television device (also referred to as a television or a television receiver), a monitor for a computer, a digital camera, a digital video camera, a digital photo frame, a mobile phone (also referred to as a mobile phone or a mobile phone device). And large game machines such as portable game machines, portable information terminals, sound reproduction apparatuses, and pachinko machines. Specific examples of these electronic devices are shown below.

FIG. 9A illustrates an example of a television device. In the television device, a display portion 7103 is incorporated in a housing 7101. Here, a structure in which the housing 7101 is supported by a stand 7105 is shown. An image can be displayed on the display portion 7103, and the display portion 7103 is formed by arranging light-emitting elements in a matrix.

The television device can be operated with an operation switch included in the housing 7101 or a separate remote controller 7110. Channels and volume can be operated with an operation key 7109 provided in the remote controller 7110, and an image displayed on the display portion 7103 can be operated. The remote controller 7110 may be provided with a display portion 7107 for displaying information output from the remote controller 7110.

Note that the television device is provided with a receiver, a modem, and the like. General TV broadcasts can be received by a receiver, and connected to a wired or wireless communication network via a modem, so that it can be unidirectional (sender to receiver) or bidirectional (sender and receiver). It is also possible to perform information communication between each other or between recipients).

FIG. 9B1 illustrates a computer, which includes a main body 7201, a housing 7202, a display portion 7203, a keyboard 7204, an external connection port 7205, a pointing device 7206, and the like. Note that this computer is manufactured by using light-emitting elements arranged in a matrix in the display portion 7203. The computer shown in FIG. 9B1 may have a form as shown in FIG. 9B2. A computer in FIG. 9B2 is provided with a second display portion 7210 instead of the keyboard 7204 and the pointing device 7206. The second display portion 7210 is a touch panel type, and input can be performed by operating a display for input displayed on the second display portion 7210 with a finger or a dedicated pen. In addition, the second display portion 7210 can display not only an input display but also other images. The display portion 7203 may also be a touch panel. By connecting the two screens with hinges, it is possible to prevent troubles such as damage or damage to the screens during storage or transportation.

9C and 9D illustrate an example of a portable information terminal. The portable information terminal includes a display portion 7402 incorporated in a housing 7401, operation buttons 7403, an external connection port 7404, a speaker 7405, a microphone 7406, and the like. Note that the portable information terminal includes a display portion 7402 manufactured by arranging light-emitting elements in a matrix.

The portable information terminal illustrated in FIGS. 9C and 9D can have a structure in which information can be input by touching the display portion 7402 with a finger or the like. In this case, operations such as making a call or creating a mail can be performed by touching the display portion 7402 with a finger or the like.

There are mainly three screen modes of the display portion 7402. The first mode is a display mode mainly for displaying an image. The first is a display mode mainly for displaying images, and the second is an input mode mainly for inputting information such as characters. The third is a display + input mode in which the display mode and the input mode are mixed.

For example, when making a call or creating a mail, the display portion 7402 may be set to a character input mode mainly for inputting characters, and an operation for inputting characters displayed on the screen may be performed. In this case, it is preferable to display a keyboard or number buttons on most of the screen of the display portion 7402.

In addition, by providing a detection device having a sensor for detecting inclination such as a gyroscope or an acceleration sensor inside the mobile phone, the orientation (portrait or horizontal) of the mobile phone is determined, and the screen display of the display portion 7402 is automatically displayed. Can be switched automatically.

Further, the screen mode is switched by touching the display portion 7402 or operating the operation button 7403 of the housing 7401. Further, switching can be performed depending on the type of image displayed on the display portion 7402. For example, if the image signal to be displayed on the display unit is moving image data, the mode is switched to the display mode, and if it is text data, the mode is switched to the input mode.

Further, in the input mode, when a signal detected by the optical sensor of the display unit 7402 is detected and there is no input by a touch operation of the display unit 7402 for a certain period, the screen mode is switched from the input mode to the display mode. You may control.

The display portion 7402 can function as an image sensor. For example, personal authentication can be performed by touching the display portion 7402 with a palm or a finger and capturing an image of a palm print, a fingerprint, or the like. In addition, if a backlight that emits near-infrared light or a sensing light source that emits near-infrared light is used for the display portion, finger veins, palm veins, and the like can be imaged.

Note that the above electronic devices can be combined with any of the structures described in this specification as appropriate.

The light-emitting element of one embodiment of the present invention is preferably used for the display portion. The light-emitting element can be a light-emitting element with favorable emission efficiency. Further, a light-emitting element with low driving voltage can be obtained. Therefore, an electronic device including the light-emitting element of one embodiment of the present invention can be an electronic device with low power consumption.

  FIG. 10 illustrates an example of a liquid crystal display device in which a light-emitting element is used for a backlight. The liquid crystal display device illustrated in FIG. 10 includes a housing 901, a liquid crystal layer 902, a backlight unit 903, and a housing 904, and the liquid crystal layer 902 is connected to a driver IC 905. A light emitting element is used for the backlight unit 903, and current is supplied from a terminal 906.

  The light-emitting element of one embodiment of the present invention is preferably used as the light-emitting element, and by using the light-emitting element for a backlight of a liquid crystal display device, a backlight with reduced power consumption can be obtained.

  FIG. 11 illustrates an example of a table lamp which is one embodiment of the present invention. The desk lamp illustrated in FIG. 11 includes a housing 2001 and a light source 2002, and a lighting device using a light-emitting element as the light source 2002 is used.

  FIG. 12 illustrates an example of an indoor lighting device 3001. The light-emitting element of one embodiment of the present invention is preferably used for the lighting device 3001.

  FIG. 13 illustrates an automobile which is one embodiment of the present invention. The automobile has a light emitting element mounted on a windshield or a dashboard. Display regions 5000 to 5005 are display regions provided using light-emitting elements. The light-emitting element of one embodiment of the present invention is preferably used, and thus the display region 5000 to the display region 5005 can be used in a vehicle because power consumption can be suppressed.

  A display area 5000 and a display area 5001 are display devices using light emitting elements provided on a windshield of an automobile. By manufacturing the light-emitting element using an electrode having a light-transmitting property as an anode and a cathode, a display device in a so-called see-through state in which the opposite side can be seen can be obtained. If it is a see-through display, it can be installed without obstructing the field of view even if it is installed on the windshield of an automobile. Note that in the case where a transistor for driving or the like is provided, a light-transmitting transistor such as an organic transistor using an organic semiconductor material or a transistor using an oxide semiconductor is preferably used.

  A display region 5002 is a display device using a light emitting element provided in a pillar portion. In the display area 5002, the field of view blocked by the pillar can be complemented by projecting an image from the imaging means provided on the vehicle body. Similarly, the display area 5003 provided in the dashboard portion compensates for the blind spot by projecting an image from the imaging means provided outside the automobile from the field of view blocked by the vehicle body, thereby improving safety. Can do. By displaying the video so as to complement the invisible part, it is possible to check the safety more naturally and without a sense of incongruity.

  The display area 5004 and the display area 5005 can provide various other information such as navigation information, a speedometer, a rotation speed, a travel distance, an oil supply amount, a gear state, and an air conditioning setting. The display items and layout can be appropriately changed according to the user's preference. Note that these pieces of information can also be provided in the display area 5000 to the display area 5003. In addition, the display region 5000 to the display region 5005 can be used as a lighting device.

  FIG. 14A and FIG. 14B illustrate an example of a tablet terminal that can be folded. FIG. 14A shows an open state in which the tablet terminal includes a housing 9630, a display portion 9631a, a display portion 9631b, a display mode switching switch 9034, a power switch 9035, a power saving mode switching switch 9036, and a fastener 9033. And an operation switch 9038. Note that the tablet terminal is manufactured using the light-emitting device including the light-emitting element of one embodiment of the present invention for one or both of the display portion 9631a and the display portion 9631b.

  Part of the display portion 9631 a can be a touch panel region 9632 a and data can be input when a displayed operation key 9637 is touched. Note that in the display portion 9631a, for example, a structure in which half of the regions have a display-only function and a structure in which the other half has a touch panel function is shown, but the structure is not limited thereto. The entire region of the display portion 9631a may have a touch panel function. For example, the entire surface of the display portion 9631a can display keyboard buttons to serve as a touch panel, and the display portion 9631b can be used as a display screen.

  Further, in the display portion 9631b as well, like the display portion 9631a, part of the display portion 9631b can be a touch panel region 9632b. In addition, a keyboard button can be displayed on the display portion 9631b by touching a position where the keyboard display switching button 9639 on the touch panel is displayed with a finger, a stylus, or the like.

  Further, touch input can be performed on the touch panel region 9632a and the touch panel region 9632b at the same time.

  A display mode switching switch 9034 can switch the display direction such as vertical display or horizontal display, and can select switching between monochrome display and color display. The power saving mode change-over switch 9036 can optimize the display luminance in accordance with the amount of external light during use detected by an optical sensor built in the tablet terminal. The tablet terminal may include not only an optical sensor but also other detection devices such as a gyroscope, an acceleration sensor, and other sensors that detect inclination.

  FIG. 14A shows an example in which the display areas of the display portion 9631b and the display portion 9631a are the same, but there is no particular limitation. One size and the other size may be different, and the display quality is also high. May be different. For example, one display panel may be capable of displaying images with higher definition than the other.

  FIG. 14B illustrates a closed state in which the tablet terminal in this embodiment includes a housing 9630, a solar cell 9633, a charge / discharge control circuit 9634, a battery 9635, and a DCDC converter 9636. Note that FIG. 14B illustrates a structure including a battery 9635 and a DCDC converter 9636 as an example of the charge / discharge control circuit 9634.

  Note that since the tablet terminal can be folded in two, the housing 9630 can be closed when not in use. Accordingly, since the display portion 9631a and the display portion 9631b can be protected, a tablet terminal with excellent durability and high reliability can be provided from the viewpoint of long-term use.

  In addition, the tablet terminal shown in FIGS. 14A and 14B has a function for displaying various information (still images, moving images, text images, etc.), a calendar, a date, or a time. A function for displaying on the display unit, a touch input function for performing touch input operation or editing of information displayed on the display unit, a function for controlling processing by various software (programs), and the like can be provided.

  Electric power can be supplied to the touch panel, the display unit, the video signal processing unit, or the like by the solar battery 9633 mounted on the surface of the tablet terminal. Note that it is preferable that the solar battery 9633 be provided on one or two surfaces of the housing 9630 because the battery 9635 can be efficiently charged.

  The structure and operation of the charge / discharge control circuit 9634 illustrated in FIG. 14B are described with reference to a block diagram in FIG. FIG. 14C illustrates the solar battery 9633, the battery 9635, the DCDC converter 9636, the converter 9638, the switches SW1 to SW3, and the display portion 9631. The battery 9635, the DCDC converter 9636, the converter 9638, and the switches SW1 to SW3 are illustrated. This corresponds to the charge / discharge control circuit 9634 shown in FIG.

  First, an example of operation in the case where power is generated by the solar battery 9633 using external light is described. The power generated by the solar battery is boosted or lowered by the DCDC converter 9636 so as to be a voltage for charging the battery 9635. When the power charged in the solar battery 9633 is used for the operation of the display portion 9631, the switch SW1 is turned on, and the converter 9638 increases or decreases the voltage required for the display portion 9631. In the case where display on the display portion 9631 is not performed, the battery 9635 may be charged by turning off SW1 and turning on SW2.

  Note that although the solar cell 9633 is shown as an example of the power generation unit, the power generation unit is not particularly limited, and the battery 9635 is charged by another power generation unit such as a piezoelectric element (piezo element) or a thermoelectric conversion element (Peltier element). The structure which performs this may be sufficient. A non-contact power transmission module that wirelessly (contactlessly) transmits and receives power for charging and a combination of other charging means may be used, and the power generation means may not be provided.

Further, as long as the display portion 9631 is included, the tablet terminal is not limited to the shape illustrated in FIG.

15A to 15C illustrate a foldable portable information terminal 9310. FIG. FIG. 15A illustrates the portable information terminal 9310 in a developed state. FIG. 15B illustrates the portable information terminal 9310 in a state in which the state is changing from one of the developed state or the folded state to the other. FIG. 15C illustrates the portable information terminal 9310 in a folded state. The portable information terminal 9310 is excellent in portability in the folded state and excellent in display listability due to a seamless wide display area in the expanded state.

The display panel 9311 is supported by three housings 9315 connected by hinges 9313. Note that the display panel 9311 may be a touch panel (input / output device) equipped with a touch sensor (input device). The display panel 9311 can be reversibly deformed from a developed state to a folded state by bending the two housings 9315 via the hinge 9313. The light-emitting device of one embodiment of the present invention can be used for the display panel 9311. A display region 9312 in the display panel 9311 is a display region located on a side surface of the portable information terminal 9310 in a folded state. In the display area 9312, information icons, frequently used applications, program shortcuts, and the like can be displayed, so that information can be confirmed and applications can be activated smoothly.

<< Synthesis Example 1 >>
This synthesis example is an organic compound of one embodiment of the present invention, 9,9 ′-[(5-methylpyrimidine-4,6-diyl) bis (3,1-phenylene)] bis (9H-carbazole) (abbreviation) : 5Me-4,6mCzP2Pm) will be described in detail. The structural formula of 5Me-4,6mCzP2Pm is shown below.

<Method for synthesizing 5Me-4,6mCzP2Pm>
0.85 g (5.2 mmol) 4,6-dichloro-5-methylpyrimidine, 3.3 g (11 mmol) 3- (9H-carbazol-9-yl) phenylboronic acid, 0.16 g (0. 53 mmol) of tris (2-methylphenyl) phosphine was placed in a 100 mL three-necked flask, and the atmosphere in the flask was replaced with nitrogen. To this mixture, 11 mL of 2M aqueous potassium carbonate solution, 27 mL of toluene and 9 mL of ethanol were added, and degassed by stirring under reduced pressure. 23 mg (0.10 mmol) of palladium (II) acetate was added to this mixture, and the mixture was stirred at 90 ° C. for 6 hours under a nitrogen stream.

After stirring, water was added to the mixture, and the aqueous layer was extracted with ethyl acetate. The obtained extract and the organic layer were combined, washed with water and saturated brine, and dried over magnesium sulfate. The mixture was separated by gravity filtration, and the filtrate was concentrated to give a brown oil. This oily substance was purified by silica gel column chromatography (developing solvent: hexane: ethyl acetate = 5: 1). The obtained fraction was concentrated to obtain a yellow solid. When this solid was recrystallized with hot ethyl acetate, 1.3 g of a pale yellow solid as a target product was obtained in a yield of 43%.

Sublimation purification of 1.3 g of the obtained pale yellow solid was performed by a train sublimation method. The sublimation purification was performed by heating a pale yellow solid at 235 ° C. under conditions of a pressure of 2.8 Pa and an argon flow rate of 5 mL / min. After purification by sublimation, a white solid was obtained in a yield of 0.95 g and a recovery rate of 73%. A synthesis scheme is shown below.

¹ H-NMR of the obtained white solid was measured. The chart is shown in FIG. The numerical data is shown below. Thereby, it turned out that 5Me-4,6mCzP2Pm was obtained by this synthesis example.

¹ H-NMR (CDCl ₃ , 300 MHz): δ = 2.56 (s, 3H), 7.27-7.33 (m, 4H), 7.39-7.48 (m, 8H), 7. 70-7.80 (m, 6H), 7.86-7.87 (m, 2H), 8.15 (d, J = 7.8 Hz, 2H), 9.22 (s, 1H).

Next, FIG. 17 shows the results of measuring the absorption spectrum and emission spectrum of a toluene solution of 5Me-4,6mCzP2Pm. In addition, FIG. 18 shows an absorption spectrum and an emission spectrum of the thin film. The solid thin film was produced on a quartz substrate by a vacuum deposition method. For the measurement of the absorption spectrum of the toluene solution, an ultraviolet-visible spectrophotometer (model V550 manufactured by JASCO Corporation) was used, and the spectrum measured by placing only toluene in a quartz cell was subtracted. Further, a spectrophotometer (Spectrophotometer U4100 manufactured by Hitachi High-Technologies Corporation) was used for measuring the absorption spectrum of the thin film. In addition, a fluorometer (FS920 manufactured by Hamamatsu Photonics Co., Ltd.) was used for measuring the emission spectrum.

From FIG. 17, in the toluene solution of 5Me-4,6mCzP2Pm, absorption peaks were observed in the vicinity of 340 nm, 325 nm, 291 nm, and 286 nm, and the emission wavelength peak was 418 nm (excitation wavelength: 340 nm). In addition, from FIG. 18, the 5Me-4,6mCzP2Pm thin film has absorption peaks around 343 nm, 330 nm, 314 nm, 295 nm, 288 nm, 265 nm, 241 nm and 209 nm, and the emission wavelength peak is around 418 nm (excitation wavelength 343 nm). It was seen. From this result, it was found that 5Me-4,6mCzP2Pm can also be used as a host for a fluorescent material in the visible range.

Structural formulas of organic compounds used in the light-emitting element 1, the comparative light-emitting element 1, and the comparative light-emitting element 2 are shown below.

(Method for Manufacturing Light-Emitting Element 1)
First, indium tin oxide containing silicon oxide (ITSO) was formed over a glass substrate by a sputtering method, whereby the anode 101 was formed. The film thickness was 70 nm, and the electrode area was 4 mm ² (2 mm × 2 mm).

Next, as a pretreatment for forming a light-emitting element over the substrate, the surface of the substrate was washed with water, baked at 200 ° C. for 1 hour, and then subjected to UV ozone treatment for 370 seconds.

Thereafter, the substrate is introduced into a vacuum vapor deposition apparatus whose internal pressure is reduced to about 10 ⁻⁴ Pa, vacuum baking is performed at 170 ° C. for 30 minutes in a heating chamber in the vacuum vapor deposition apparatus, and then the substrate is released for about 30 minutes. Chilled.

Next, the substrate on which the anode 101 is formed is fixed to a substrate holder provided in the vacuum deposition apparatus so that the surface on which the anode 101 is formed is downward, and vapor deposition using resistance heating is performed on the anode 101. 4,4 ′, 4 ″-(benzene-1,3,5-triyl) tri (dibenzothiophene) (abbreviation: DBT3P-II) and molybdenum oxide (VI) represented by the structural formula (i) by the above method Were vapor-deposited to a weight ratio of 2: 1 (= DBT3P-II: molybdenum oxide) to form a hole injection layer 111.

Next, 3,3′-bis (9-phenyl-9H-carbazole) (abbreviation: PCCP) represented by the above structural formula (ii) is deposited over the hole injection layer 111 so as to have a thickness of 20 nm. Then, a hole transport layer 112 was formed.

Subsequently, PCCP and 9,9 ′-[(5-methylpyrimidine-4,6-diyl) bis (3,1-phenylene)] bis (9H-carbazole) represented by the structural formula (100) ( Abbreviation: 5Me-4,6mCzP2Pm) and tris {2- [5- (2-methylphenyl) -4- (2,6-diisopropylphenyl) -4H-1,2 represented by the above structural formula (iii)] , 4-triazol-3-yl-κN2] phenyl-κC} iridium (III) (abbreviation: [Ir (mppptz-diPrp) ₃ ]) in a weight ratio of 1: 0.3: 0.06 (= PCCP: 5Me-4,6mCzP2Pm: [Ir (mpptz -diPrp) 3]) and was deposited 30nm co so, the 5ME-4,6mCzP2Pm, and _{[Ir (mpptz-diPrp) 3} ], Ratio 1: 0.06: was (= 5Me-4,6mCzP2Pm [Ir ( mpptz-diPrp) 3]) and so as to be deposited 10nm co to form a light-emitting layer 113.

After that, 5Me-4,6mCzP2Pm is deposited on the light-emitting layer 113 so as to have a film thickness of 10 nm, and then bathophenanthroline (abbreviation: BPhen) represented by the above structural formula (iv) is formed to a film thickness of 15 nm. The electron transport layer 114 was formed by vapor deposition.

After forming the electron transport layer 114, lithium fluoride (LiF) is deposited to a thickness of 1 nm to form the electron injection layer 115, and then aluminum is deposited to a thickness of 200 nm. The cathode 102 was formed to manufacture the light-emitting element 1 of this example.

(Method for Manufacturing Comparative Light-Emitting Element 1)
In the comparative light-emitting element 1, 5Me-4,6mCzP2Pm in the light-emitting element 1 is replaced with 3,5-bis [3- (9H-carbazol-9-yl) phenyl] pyridine represented by the structural formula (v) (abbreviation: The light-emitting element 1 was manufactured in the same manner except that 35DCzPPy) was used.

(Method for Manufacturing Comparative Light-Emitting Element 2)
In the comparative light-emitting element 2, 5Me-4,6mCzP2Pm in the light-emitting element 1 is replaced with 4,6-bis [3- (9H-carbazol-9-yl) phenyl] pyrimidine represented by the structural formula (vi) (abbreviation: It was fabricated in the same manner as the light-emitting element 1 except that it was changed to 4,6mCzP2Pm).

The element structures of the light-emitting element 1, the comparative light-emitting element 1, and the comparative light-emitting element 2 are summarized in the following table.

The operation of sealing the light-emitting element 1, the comparative light-emitting element 1 and the comparative light-emitting element 2 with a glass substrate in a glove box in a nitrogen atmosphere so that the light-emitting element is not exposed to the atmosphere (a sealant is applied around the element, After performing UV treatment at the time of sealing and heat treatment at 80 ° C. for 1 hour, the initial characteristics and reliability of these light-emitting elements were measured. The measurement was performed in an atmosphere kept at 25 ° C.

The luminance-current density characteristics of the light-emitting element 1, the comparative light-emitting element 1, and the comparative light-emitting element 2 are shown in FIG. 19, the luminance-voltage characteristics are shown in FIG. 20, the current efficiency-luminance characteristics are shown in FIG. FIG. 23 shows the chromaticity-luminance characteristics, FIG. 24 shows the external quantum efficiency-luminance characteristics, and FIG. 25 shows the emission spectrum. Table 3 shows main characteristics of each light-emitting element around 1000 cd / m ² .

19 to 24 and Table 3, the light-emitting element 1 which is one embodiment of the present invention is a light-emitting element having a driving voltage as low as that of the comparative light-emitting element 1, good efficiency, and good blue color. all right. Further, in comparison with the comparative light-emitting element 2, there is a clear difference in efficiency and driving voltage regardless of whether or not the 5-position methyl group of the substance used as the electron transport material is present. It was. This is because the 5-position methyl group in 5Me-4,6mCzP2Pm affects the angle of the phenylene group. As a result, the LUMO level of 5Me-4,6mCzP2Pm becomes shallower than the LUMO level of 4,6mCzP2Pm. Exciplex formation between the material [Ir (mppptz-diPrp) ₃ ] and the electron transport material is suppressed, and the emission of [Ir (mppptz-diPrp) ₃ ], which is the light-emitting material, is less likely to be hindered. Conceivable.

It can be seen from the emission spectrum of FIG. 24 that the comparative light-emitting element 2 has a relatively large amount of exciplex formation between the light-emitting material and another material. The shape of the emission spectrum of the comparative light-emitting element 2 has a large peak on the long wavelength side compared to the other two elements. This is because the light-emitting substance forms an exciplex with another substance and is excited with less energy. This suggests that a state has been formed. Further, as can be seen from the chromaticity-luminance characteristics of FIG. 23 and the chromaticity of Table 2, the comparative light-emitting element 2 has a large ratio of the second peak on the long wavelength side, and therefore the other two elements. The color has changed. A change in color as the brightness increases is also a feature of a light-emitting device in which an exciplex is formed.

In addition, FIG. 26 shows a graph showing a change in luminance with respect to driving time under the condition that the initial luminance is 2000 cd / m ² and the current density is constant. As shown in FIG. 26, it was found that the light-emitting element 1 was a light-emitting element with a small lifetime and a good lifetime due to accumulation of driving time. Since the comparative light-emitting element 2 has low efficiency, it is considered that the addition was large and the luminance was greatly reduced in the driving test in which the luminance was constant. On the other hand, the comparative light-emitting element 1 has the same luminous efficiency as that of the light-emitting element 1, but has a large decrease in luminance. This is related to whether or not an exciplex is formed with the assist material PCCP. In the light-emitting element 1 in which PCCP and the electron transport material 5Me-4,6mCzP2Pm form an exciplex, the singlet excited state and the triplet excited state are used. , The energy for excitation can be kept relatively low. On the other hand, 3,5DCzPPy does not form an exciplex with PCCP because LUMO is shallow. Therefore, in order to obtain triplet excitation energy that can transfer energy to the triplet excited state of the light-emitting material, a singlet excited state that is a higher energy level must be formed. Giving itself a heavy load. Therefore, it is considered that the comparative light-emitting element 1 using 3,5DCzPPy is an element having a shorter lifetime than the light-emitting element 1 while having high efficiency.

As described above, it was found that the light-emitting element 1 using 5Me-4,6mCzP2Pm as an electron-transporting material was a light-emitting element with good characteristics, both good luminous efficiency and long life. This is because 5Me-4,6mCzP2Pm has an alkyl group at the 5-position, and as a result of controlling the angle of the phenylene group, the LUMO level becomes shallow, and it is possible to suppress the formation of exciplex with the light-emitting material. It is.

Note that addition of an alkyl group at the 5-position also has the effect of increasing the triplet excitation level, and the utility value in the phosphorescent light-emitting element can be increased.

DESCRIPTION OF SYMBOLS 101 Anode 102 Cathode 103 EL layer 111 Hole injection layer 112 Hole transport layer 113 Light emitting layer 114 Electron transport layer 115 Electron injection layer 116 Charge generation layer 117 P-type layer 118 Electron relay layer 119 Electron injection buffer layer 400 Substrate 401 Anode 403 EL layer 404 Cathode 405 Sealing material 406 Sealing material 407 Sealing substrate 412 Pad 420 IC chip 501 Anode 502 Cathode 511 First light emitting unit 512 Second light emitting unit 513 Charge generation layer 601 Drive circuit portion (source line drive circuit)
602 Pixel portion 603 Drive circuit portion (gate line drive circuit)
604 Sealing substrate 605 Sealing material 607 Space 608 Wiring 609 FPC (flexible printed circuit)
610 Element substrate 611 FET for switching
612 FET for current control
613 Anode 614 Insulator 616 EL layer 617 Cathode 618 Light emitting element 730 Insulating film 770 Flattened insulating film 772 Conductive film 782 Light emitting element 783 Droplet discharge device 784 Droplet 785 layer 786 EL layer 788 Conductive film 901 Housing 902 Liquid crystal layer 903 Backlight unit 904 Case 905 Driver IC
906 terminal 951 substrate 952 electrode 953 insulating layer 954 partition layer 955 EL layer 956 electrode 1001 substrate 1002 base insulating film 1003 gate insulating film 1006 gate electrode 1007 gate electrode 1008 gate electrode 1020 first interlayer insulating film 1021 second interlayer insulating film 1022 Electrode 1024W Anode 1024R Anode 1024G Anode 1024B Anode 1025 Partition 1028 EL layer 1029 Cathode 1031 Sealing substrate 1032 Sealing material 1033 Transparent substrate 1034R Red colored layer 1034G Green colored layer 1034B Blue colored layer 1035 Black matrix 1037 Third Interlayer insulating film 1040 Pixel portion 1041 Drive circuit portion 1042 Peripheral portion 1400 Droplet discharge device 1402 Substrate 1403 Droplet discharge portion 1404 Imaging portion 1405 Head 1406 Dotted line 1407 Control means 1408 Storage medium 1409 Image processing means 1410 Computer 1411 Marker 1412 Head 1413 Material supply source 1414 Material supply source 1415 Material supply source 1416 Head 2001 Housing 2002 Light source 3001 Illuminating device 5000 Display area 5001 Display area 5002 Display area 5003 Display area 5004 Display area 5005 Display area 7101 Case 7103 Display unit 7105 Stand 7107 Display unit 7109 Operation key 7110 Remote control device 7201 Main body 7202 Case 7203 Display unit 7204 Keyboard 7205 External connection port 7206 Pointing device 7210 Second display unit 7401 Case 7402 Display portion 7403 Operation button 7404 External connection port 7405 Speaker 7406 Microphone 9033 Fastener 9 34 switch 9035 power switch 9036 switch 9038 operation switch 9310 portable information terminal 9311 display panel 9312 display region 9313 hinge 9315 housing 9630 housing 9631 display unit 9631a display unit 9631b display unit 9632a touch panel region 9632b touch panel region 9633 solar cell 9634 charge / discharge control Circuit 9635 Battery 9636 DCDC converter 9537 Operation key 9638 Converter 9539 Button

Claims (19)

An organic compound represented by the following general formula (G1).

(However, in General Formula (G1), R ¹ represents any one of an alkyl group having 1 to 6 carbon atoms, and independently of the carbon atoms at positions A and B, the following General Formula (G2-1) or The group represented by (G2-2) is bonded.)

(However, in General Formula (G2-1), X ¹ represents any ^one of a nitrogen atom, an oxygen atom, a sulfur atom, and a carbon atom. When X ¹ is a nitrogen atom or a carbon atom, one nitrogen atom is The carbon atom may have one or two substituents, and R ^{11 to} R ¹⁸ each independently represents hydrogen or any one of an alkyl group having 1 to 6 carbon atoms. One of R ^{11 to} R ¹⁴ may be a bond, and when X ¹ is nitrogen, the carbon at the position A in General Formula (G1) depends on any one of the bonds that nitrogen has. Or bonded to the carbon at position B.)

(However, in General Formula (G2-2), X ² represents any one of a nitrogen atom, an oxygen atom, a sulfur atom, and a carbon atom. When X ² is a nitrogen atom or a carbon atom, one nitrogen atom is The carbon atom may have one or two substituents, and R ^{21 to} R ²⁸ each independently represent hydrogen or any one of an alkyl group having 1 to 6 carbon atoms. One of R ^{21 to} R ²⁴ may be a bond, and when X ² is nitrogen, the bond at position A in General Formula (G1) is determined by any one of the bonds of nitrogen. It binds to carbon or carbon at the position of B. α and β represent a ring fused with two adjacent rings, α represents a ring represented by the following general formula (G3), β represents the following general formula ( Represents a ring represented by G4).)

(The ring represented by the general formula (G3) is condensed with two adjacent rings at the position of ac or ad in the formula (G3). R ³¹ and R ³² are each independently hydrogen or carbon number. Represents any one of 1 to 6 alkyl groups.)

(The ring represented by the general formula (G4) is condensed with two adjacent rings at the position bd in the formula (G4). X ³ is any one of a nitrogen atom, an oxygen atom, a sulfur atom and a carbon atom. Represents 1. When X ³ is a nitrogen atom or a carbon atom, the nitrogen atom may have one and the carbon atom may have one or two substituents. An organic compound represented by the following general formula (G1).

(However, in General Formula (G1), R ¹ represents any one of an alkyl group having 1 to 6 carbon atoms, and is independently represented by the following General Formula (G2-1) at each of carbon atoms at positions A and B. The group represented is bonded.)

(However, in General Formula (G2-1), X ¹ represents any ^one of a nitrogen atom, an oxygen atom, a sulfur atom, and a carbon atom. When 1 is a nitrogen atom or a carbon atom, one nitrogen atom, The carbon atom may have one or two substituents, and R ^{11 to} R ¹⁸ each independently represents any one of hydrogen and an alkyl group having 1 to 6 carbon atoms. ^{11 to} R ¹⁴ may be one of the bonds, and when X ¹ is nitrogen, the carbon at the position A in General Formula (G1) or X ¹ is a bond represented by the nitrogen. Bonded to carbon at position B) In claim 2, the organic compound at least one of X ¹ is a nitrogen atom. 4. The organic compound according to claim 3, wherein nitrogen of X ¹ is bonded to carbon at position A or carbon at position B in the general formula (G1). The organic compound containing the organic compound represented by the following general formula (G1).

(In the general formula (G1), R ¹ represents any one of alkyl groups having 1 to 6 carbon atoms, and independently of the carbon atoms at positions A and B, the following general formula (G2-2)
A group represented by )

(However, in General Formula (G2-2), X ² represents any one of a nitrogen atom, an oxygen atom, a sulfur atom, and a carbon atom. When X ² is a nitrogen atom or a carbon atom, one nitrogen atom is The carbon atom may have one or two substituents, and R ^{21 to} R ²⁸ each independently represents any one of hydrogen and an alkyl group having 1 to 6 carbon atoms. ^{21 to} R ²⁴ may be one of the bonds, and when X ² is nitrogen, the carbon at the position of A in the general formula (G1) depends on any one of the bonds of nitrogen. Or, it binds to the carbon at position B. α and β represent a ring fused with two adjacent rings, α represents a ring represented by the following general formula (G3), and β represents a general formula (G4 ) Represents a ring represented by

(The ring represented by the general formula (G3) is condensed with two adjacent rings in the position of ac or ad in the formula (G3). R ³¹ and R ³² are each independently hydrogen or carbon number. Represents any one of 1 to 6 alkyl groups.)

(The ring represented by the general formula (G4) is condensed with two adjacent rings at the position bd in the formula (G4), and X ³ is any one of a nitrogen atom, an oxygen atom, a sulfur atom and a carbon atom. Represents 1. When X ³ is a nitrogen atom or a carbon atom, the nitrogen atom may have one and the carbon atom may have one or two substituents. In claim 5, the organic compound at least one of X ² is a nitrogen atom. The organic compound according to claim 6, wherein nitrogen of X ² is bonded to carbon at position A or carbon at position B in the general formula (G1). An organic compound represented by the following general formula (G5).

(However, in the formula represented by the general formula (G5), R ¹ represents an alkyl group having 1 to 6 carbon atoms, and R ^{41 to} R ⁴⁸ and R ^{51 to} R ⁵⁸ are each independently hydrogen or 1 carbon atom. Represents any one of alkyl groups of 6 to 6.) An organic compound represented by the following general formula (G6).

(However, in the formula represented by the general formula (G6), R ¹ represents an alkyl group having 1 to 6 carbon atoms, and R ^{61 to} R ⁶⁷ and R ^{71 to} R ⁷⁷ are each independently hydrogen or 1 carbon atom. Represents any one of alkyl groups of 6 to 6.) Organic compounds represented by the following general formulas (G7) to (G10).

(However, in General Formulas (G7) to (G10), R ¹ represents an alkyl group having 1 to 6 carbon atoms.) An organic compound represented by the following general formula (g1).

(However, in General Formula (g1), R ¹ represents any one of alkyl groups having 1 to 6 carbon atoms.) An organic compound represented by the following structural formula (100).
A light-emitting element including an organic compound having a skeleton represented by the following general formula (G1) and having a molecular weight of 3000 or less.

(However, in General Formula (G1), R ¹ represents any one of alkyl groups having 1 to 6 carbon atoms. The organic compound represented by General Formula (G1) is a carbon atom at the positions of A and B. Each has a substituent.) A light-emitting element including an organic compound having a skeleton represented by the following general formula (G1) and having a molecular weight of 3000 or less.

(In the general formula (G1), R ¹ represents any one of alkyl groups having 1 to 6 carbon atoms, and a carbazole skeleton, a fluorene skeleton, a dibenzothiophene skeleton, and a dibenzofuran skeleton at each of the carbon atoms at positions A and B. A substituent containing any one of the skeletons.) The light emitting element containing the organic compound as described in any one of Claims 1 thru | or 12. In any one of Claims 13 thru / or Claim 15,
The light-emitting element includes at least a light-emitting layer, and the light-emitting layer includes the organic compound. A light-emitting device comprising the light-emitting element according to claim 13 and a transistor or a substrate. An electronic apparatus comprising: the light-emitting device according to claim 17; and a sensor, an operation button, a speaker, or a microphone. An illumination device comprising: a light emitting device having the configuration according to claim 18; and a housing.