Light-emitting element, display device, electronic apparatus, and lighting device

Abstract

To provide a light-emitting element with high emission efficiency.SOLUTION: The light-emitting element includes a first organic compound, a second organic compound, and a guest material. The LUMO level of the first organic compound is lower than the LUMO level of the second organic compound. The HOMO level of the first organic compound is lower than the HOMO level of the second organic compound. The HOMO level of the guest material is higher than the HOMO level of the second organic compound. The energy difference between the LUMO level of the guest material and the HOMO level of the guest material is larger than the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound. The guest material has a function of allowing conversion of triplet excitation energy into light emission. The first organic compound and the second organic compound are a combination forming an exciplex.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] One aspect of the present invention relates to a light-emitting element, or a display device, an electronic device, and an illumination device having the light-emitting element. Note that one aspect of the present invention is not limited to the above technical field. The technical field of one aspect of the invention disclosed in this specification and the like relates to an article, a method, or a manufacturing method. Or, one aspect of the present invention relates to a process, a machine, a manufacture, or a composition of matter. Therefore, more specifically, examples of the technical field of one aspect of the present invention disclosed in this specification include semiconductor devices, display devices, liquid crystal display devices, light-emitting devices, illumination devices, power storage devices, storage devices, driving methods thereof, or manufacturing methods thereof.

[0002] Note that one aspect of the present invention is not limited to the above technical field. The technical field of one aspect of the invention disclosed in this specification and the like relates to an article, a method, or a manufacturing method. Or, one aspect of the present invention relates to a process, a machine, a manufacture, or a composition of matter. Therefore, more specifically, examples of the technical field of one aspect of the present invention disclosed in this specification include semiconductor devices, display devices, liquid crystal display devices, light-emitting devices, illumination devices, power storage devices, storage devices, driving methods thereof, or manufacturing methods thereof. Note that one aspect of the present invention is not limited to the above technical field. The technical field of one aspect of the invention disclosed in this specification and the like relates to an article, a method, or a manufacturing method. Or, one aspect of the present invention relates to a process, a machine, a manufacture, or a composition of matter. Therefore, more specifically, examples of the technical field of one aspect of the present invention disclosed in this specification include semiconductor devices, display devices, liquid crystal display devices, light-emitting devices, illumination devices, power storage devices, storage devices, driving methods thereof, or manufacturing methods thereof. Note that one aspect of the present invention is not limited to the above technical field. The technical field of one aspect of the invention disclosed in this specification and the like relates to an article, a method, or a manufacturing method. Or, one aspect of the present invention relates to a process, a machine, a manufacture, or a composition of matter. Therefore, more specifically, examples of the technical field of one aspect of the present invention disclosed in this specification include semiconductor devices, display devices, liquid crystal display devices, light-emitting devices, illumination devices, power storage devices, storage devices, driving methods thereof, or manufacturing methods thereof. Note that one aspect of the present invention is not limited to the above technical field. The technical field of one aspect of the invention disclosed in this specification and the like relates to an article, a method, or a manufacturing method. Or, one aspect of the present invention relates to a process, a machine, a manufacture, or a composition of matter. Therefore, more specifically, examples of the technical field of one aspect of the present invention disclosed in this specification include semiconductor devices, display devices, liquid crystal display devices, light-emitting devices, illumination devices, power storage devices, storage devices, driving methods thereof, or manufacturing methods thereof. Note that one aspect of the present invention is not limited to the above technical field. The technical field of one aspect of the invention disclosed in this specification and the like relates to an article, a method, or a manufacturing method. Or, one aspect of the present invention relates to a process, a machine, a manufacture, or a composition of matter. Therefore, more specifically, examples of the technical field of one aspect of the present invention disclosed in this specification include semiconductor devices, display devices, liquid crystal display devices, light-emitting devices, illumination devices, power storage devices, storage devices, driving methods thereof, or manufacturing methods thereof. Note that one aspect of the present invention is not limited to the above technical field. The technical field of one aspect of the invention disclosed in this specification and the like relates to an article, a method, or a manufacturing method. Or, one aspect of the present invention relates to a process, a machine, a manufacture, or a composition of matter. Therefore, more specifically, examples of the technical field of one aspect of the present invention disclosed in this specification include semiconductor devices, display devices, liquid crystal display devices, light-emitting devices, illumination devices, power storage devices, storage devices, driving methods thereof, or manufacturing methods thereof.

Background Art

[0003] In recent years, research and development of light-emitting elements using electroluminescence (EL) have been actively conducted. The basic configuration of these light-emitting elements is a configuration in which a layer (EL layer) containing a light-emitting material is sandwiched between a pair of electrodes. By applying a voltage between the electrodes of this element, light emission from the light-emitting material can be obtained. Since the above-described light-emitting element is a self-luminous type, a display device using the same has advantages such as excellent visibility, no need for a backlight, and low power consumption. Furthermore, it also has advantages such as being able to be manufactured in a thin and lightweight manner and having a high response speed. Since the above-described light-emitting element is a self-luminous type, a display device using the same has advantages such as excellent visibility, no need for a backlight, and low power consumption. Furthermore, it also has advantages such as being able to be manufactured in a thin and lightweight manner and having a high response speed. Since the above-described light-emitting element is a self-luminous type, a display device using the same has advantages such as excellent visibility, no need for a backlight, and low power consumption. Furthermore, it also has advantages such as being able to be manufactured in a thin and lightweight manner and having a high response speed.

[0004] Since the above-described light-emitting element is a self-luminous type, a display device using the same has advantages such as excellent visibility, no need for a backlight, and low power consumption. Furthermore, it also has advantages such as being able to be manufactured in a thin and lightweight manner and having a high response speed. Since the above-described light-emitting element is a self-luminous type, a display device using the same has advantages such as excellent visibility, no need for a backlight, and low power consumption. Furthermore, it also has advantages such as being able to be manufactured in a thin and lightweight manner and having a high response speed. Since the above-described light-emitting element is a self-luminous type, a display device using the same has advantages such as excellent visibility, no need for a backlight, and low power consumption. Furthermore, it also has advantages such as being able to be manufactured in a thin and lightweight manner and having a high response speed.

[0005] An organic material is used as the light-emitting material, and an EL layer containing the light-emitting material is provided between a pair of electrodes. In the case of a light-emitting element (for example, an organic EL element), a voltage is applied between a pair of electrodes. Electrons are injected from the cathode and holes are injected from the anode into the EL layer, producing a current. The injected electrons and holes are then recombined to form a light-emitting organic material. is excited, and light can be emitted from the excited light-emitting organic material.

[0006] The types of excited states that organic materials can form include singlet excited states (S * ) and triplet excited states state(T * ) emission from the singlet excited state is fluorescence, and emission from the triplet excited state is phosphorescence. The statistical generation ratio of these in a light-emitting element is called S * :T * =1 Therefore, it is more efficient to use a light-emitting element that emits phosphorescence than a light-emitting element that uses a material that emits fluorescence (fluorescent material). Therefore, a light-emitting element using a material that emits light (phosphorescent material) can have higher luminous efficiency. Therefore, a phosphorescent material capable of converting the energy of the triplet excited state into light emission is used. In recent years, light-emitting elements having such properties have been actively developed (see, for example, Patent Document 1).

[0007] The energy required to excite an organic material is determined by the LUMO and HOMO levels of the organic material. The energy difference depends on the energy difference between the excited state and the singlet state. In a light-emitting element using an organic material that emits phosphorescence, the triplet excitation energy is The energy is converted into light emission. Therefore, the singlet excited state and triplet excited state formed by organic materials When the energy difference between the excited state and the excited state is large, the energy required to excite the organic material is The energy difference between the two is the energy of the light emitted. Well, the difference between the energy required to excite the organic material and the energy of the emission affects the device characteristics as an increase in the driving voltage in the light-emitting element. However, development is underway for a method to suppress such an increase in the driving voltage (see Patent Document 2). Among light-emitting elements using a phosphorescent material, especially in a light-emitting element that exhibits blue emission, it is difficult to develop a stable compound having a high triplet excitation energy level, and thus it has not yet been put into practical use. Therefore, development of a phosphorescent material having high luminous efficiency and stability is demanded. Also, development of a phosphorescent light-emitting element having high luminous efficiency and excellent reliability is demanded.

[0008]

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0010] Iridium complexes are known as phosphorescent materials that exhibit high luminous efficiency. Also, as iridium complexes having high emission energy, iridium complexes having a pyridine skeleton or a nitrogen-containing five-membered heterocyclic skeleton in the ligand are known. The pyridine skeleton or the nitrogen-containing five-membered heterocyclic skeleton has a high triplet excitation energy level, but since its electron-accepting property is low, the iridium complex having this skeleton in the ligand has a high HOMO level and LUMO level, and hole carriers are injected. in the ligand has high HOMO and LUMO levels, and hole carriers are injected. ​​​​​​​​​It is easy to insert and difficult for electrons to be injected. Therefore, in the case of an iridium complex having high emission energy, excitation by direct recombination of carriers may be difficult, or it may be difficult to efficiently emit light from a light-emitting device. In an iridium complex, there are cases where excitation by direct recombination of carriers is difficult or it is difficult to efficiently emit light from a light-emitting device.

[0011] Therefore, one aspect of the present invention is to provide a light-emitting device having a phosphorescent material and having high luminous efficiency as one of the problems. Or, one aspect of the present invention is to provide a light-emitting device with reduced power consumption as one of the problems. Or, one aspect of the present invention is to provide a highly reliable light-emitting device as one of the problems. Or, one aspect of the present invention is to provide a novel light-emitting device as one of the problems. Or, one aspect of the present invention is to provide a novel light-emitting device as one of the problems. Or, one aspect of the present invention is to provide a novel display device as one of the problems. Or, one aspect of the present invention is to provide a light-emitting device with reduced power consumption as one of the problems. Or, one aspect of the present invention is to provide a highly reliable light-emitting device as one of the problems. Or, one aspect of the present invention is to provide a novel light-emitting device as one of the problems. Or, one aspect of the present invention is to provide a novel light-emitting device as one of the problems. Or, one aspect of the present invention is to provide a novel display device as one of the problems. Or, one aspect of the present invention is to provide a highly reliable light-emitting device as one of the problems. Or, one aspect of the present invention is to provide a novel light-emitting device as one of the problems. Or, one aspect of the present invention is to provide a novel light-emitting device as one of the problems. Or, one aspect of the present invention is to provide a novel display device as one of the problems. Or, one aspect of the present invention is to provide a novel light-emitting device as one of the problems. Or, one aspect of the present invention is to provide a novel light-emitting device as one of the problems. Or, one aspect of the present invention is to provide a novel display device as one of the problems. Or, one aspect of the present invention is to provide a novel light-emitting device as one of the problems. Or, one aspect of the present invention is to provide a novel display device as one of the problems. Or, one aspect of the present invention is to provide a novel display device as one of the problems. as one of the problems.

[0012] Note that the description of the above problems does not prevent the existence of other problems. Note that one aspect of the present invention does not necessarily need to solve all of these problems. Other problems are obvious from the description in the specification and the like, and it is possible to extract other problems from the description in the specification and the like. Note that one aspect of the present invention does not necessarily need to solve all of these problems. Other problems are obvious from the description in the specification and the like, and it is possible to extract other problems from the description in the specification and the like. It is obvious from the description in the specification and the like, and it is possible to extract other problems from the description in the specification and the like.

Means for Solving the Problems

[0013] One aspect of the present invention is a light-emitting device having an excitation complex that can efficiently excite a phosphorescent material.

[0014] Therefore, one aspect of the present invention is a light-emitting device having a first organic compound, a second organic compound, and a guest material, wherein the LUMO level of the first organic compound is lower than the LUMO level of the second organic compound. ​​​Lower than the LUMO level of the object, the HOMO level of the first organic compound is lower than the H OMO level of the second organic compound, and the HOMO level of the guest material is higher than the HOMO level of the second organic compound The energy difference between the LUMO level of the guest material and the HOMO level of the guest material is Greater than the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound, and the guest material has a function capable of converting triplet excitation energy into light emission And it is a light-emitting device in which the first organic compound and the second organic compound form an exciplex Combination.

[0015] In the above configuration, it is preferable that the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound is equal to or greater than the transition energy calculated from the absorption edge in the absorption spectrum of the guest material. Also, it is preferable that the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound is equal to or greater than the energy of the light emission exhibited by the guest material.

[0016] Another aspect of the present invention is a light-emitting device having a first organic compound, a second organic compound, and a guest material, wherein the LUMO level of the first organic compound is lower than the LUMO level of the second organic compound, and the HOMO level of the first organic compound is lower than the HO of the second organic compound MO level, the HOMO level of the guest material is higher than the HOMO level of the second organic compound, and the energy difference between the LUMO level of the guest material and the HOMO level of the guest material is Greater than the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound, and the guest material has a function capable of converting triplet excitation energy into light emission ​​​​​​​​​which has a combination in which a first organic compound and a second organic compound form an exciplex wherein the energy difference between the LUMO level of the first organic compound and the HOMO level of the guest material is equal to or greater than the transition energy calculated from the absorption edge in the absorption spectrum of the guest material is a light-emitting device

[0017] Another aspect of the present invention is a light-emitting device including a first organic compound, a second organic compound, and a guest material wherein the LUMO level of the first organic compound is lower than the LUMO level of the second organic compound, the HOMO level of the first organic compound is lower than the HO MO level of the second organic compound, the HOMO level of the guest material is higher than the HOMO level of the second organic compound and the energy difference between the LUMO level and the HOMO level of the guest material is greater than the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound, and the guest material has a function of converting triplet excitation energy into light emission and has a combination in which the first organic compound and the second organic compound form an exciplex wherein the energy difference between the LUMO level of the first organic compound and the HOMO level of the guest material is equal to or greater than the energy of the light emission exhibited by the guest material, and is a light-emitting device wherein the energy difference between the LUMO level of the first organic compound and the HOMO level of the guest material is a light-emitting device

[0018] Further, in each of the above configurations, it is preferable that the energy difference between the LUMO level and the HOMO level of the guest material is greater than the transition energy calculated from the absorption edge in the absorption spectrum of the guest material by 0.3 eV or more

[0019] Further, in each of the above configurations, the energy difference between the LUMO level and the HOMO level of the guest material ​The energy difference between them is preferably at least 0.3 eV greater than the energy of the light emission exhibited by the guest material. It is more preferable.

[0020] In each of the above configurations, the exciplex preferably has a function of donating excitation energy to the guest material. In addition, the emission spectrum exhibited by the exciplex preferably has a region overlapping with the absorption band on the longest wavelength side of the absorption spectrum of the guest material.

[0021] In each of the above configurations, the guest material preferably contains iridium.

[0022] In each of the above configurations, the guest material has a ligand coordinated to iridium, and the ligand preferably has a cyano group and a nitrogen-containing five-membered heterocyclic skeleton. In addition, the ligand preferably has a cyano group and a triazole skeleton.

[0023] In each of the above configurations, the first organic compound preferably has a function of transporting electrons, and the second organic compound preferably has a function of transporting holes. In addition, the first organic compound preferably has a π-electron-deficient heteroaromatic ring skeleton, and the second organic compound preferably has at least one of a π-electron-excessive heteroaromatic ring skeleton or an aromatic amine skeleton.

[0024] Another aspect of the present invention is a display device including the light-emitting element having each of the above configurations and at least one of a color filter or a transistor. Another aspect of the present invention is an electronic device including the display device and at least one of a housing or a touch sensor. Another aspect of the present invention is a light-emitting element having each of the above configurations and at least one of a housing or a touch sensor. A lighting device having at least one of them. Further, one aspect of the present invention includes not only a light-emitting device having a light-emitting element but also an electronic device having a light-emitting device. Therefore, the light-emitting device described in this specification refers to an image display device or a light source (including a lighting device). Further, a display module having a connector, for example, an FPC (Flexible Printed Circuit), a TCP (Tape Carrier Package) attached to the light-emitting device, a display module having a printed wiring board provided at the tip of the TCP, or a display module in which an IC (integrated circuit) is directly mounted by a COG (Chip On Glass) method is also one aspect of the present invention. Moreover, it includes not only a light-emitting device but also an electronic device having a light-emitting device within the scope. Therefore, the light-emitting device described herein refers to an image display device or a light source (including a lighting device). In addition, a display module having a connector, for example, an FPC (Flexible Printed Circuit), a TCP (Tape Carrier Package) attached to the light-emitting device, a display module having a printed wiring board provided at the tip of the TCP, or a display module in which an IC (integrated circuit) is directly mounted by a COG (Chip On Glass) method is also one aspect of the present invention. A display module having a connector, such as an FPC (Flexible Printed Circuit) or a TCP (Tape Carrier Package), attached to the light-emitting device, a display module having a printed wiring board provided at the tip of the TCP, or a display module in which an IC (integrated circuit) is directly mounted by a COG (Chip On Glass) method is also one aspect of the present invention. A display module having a connector, such as an FPC (Flexible Printed Circuit) or a TCP (Tape Carrier Package), attached to the light-emitting device, a display module having a printed wiring board provided at the tip of the TCP, or a display module in which an IC (integrated circuit) is directly mounted by a COG (Chip On Glass) method is also one aspect of the present invention. A display module having a connector, such as an FPC (Flexible Printed Circuit) or a TCP (Tape Carrier Package), attached to the light-emitting device, a display module having a printed wiring board provided at the tip of the TCP, or a display module in which an IC (integrated circuit) is directly mounted by a COG (Chip On Glass) method is also one aspect of the present invention. A display module in which an IC (integrated circuit) is directly mounted by a COG (Chip On Glass) method on the light-emitting element is also one aspect of the present invention. A display module in which an IC (integrated circuit) is directly mounted by a COG (Chip On Glass) method on the light-emitting element is also one aspect of the present invention.

Advantages of the Invention

[0025] According to one aspect of the present invention, it is possible to provide a light-emitting element having a phosphorescent material and high luminous efficiency. Or, according to one aspect of the present invention, it is possible to provide a light-emitting element with reduced power consumption. Or, according to one aspect of the present invention, it is possible to provide a highly reliable light-emitting element. Or, according to one aspect of the present invention, it is possible to provide a novel light-emitting element. Or, according to one aspect of the present invention, it is possible to provide a novel light-emitting device. Or, according to one aspect of the present invention, it is possible to provide a novel display device. According to one aspect of the present invention, it is possible to provide a light-emitting element with reduced power consumption. According to one aspect of the present invention, it is possible to provide a highly reliable light-emitting element. According to one aspect of the present invention, it is possible to provide a novel light-emitting element. According to one aspect of the present invention, it is possible to provide a novel light-emitting device. According to one aspect of the present invention, it is possible to provide a novel display device.

[0026] Note that the description of these effects does not prevent the existence of other effects. Note that one aspect of the present invention does not necessarily have all of these effects. Note that other effects are obvious from the description in the specification, drawings, claims, etc., and it is possible to extract these other effects from the description in the specification, drawings, claims, etc. Note that one aspect of the present invention does not necessarily have to have all of these effects. Note that other effects are obvious from the description in the specification, drawings, claims, etc., and it is possible to extract these other effects from the description in the specification, drawings, claims, etc. Note that other effects are obvious from the description in the specification, drawings, claims, etc., and it is possible to extract these other effects from the description in the specification, drawings, claims, etc. Note that other effects are obvious from the description in the specification, drawings, claims, etc., and it is possible to extract these other effects from the description in the specification, drawings, claims, etc.

Brief Description of the Drawings

[0027]

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Mode for Carrying Out the Invention

[0028] 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 its form and details can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention is not interpreted as being limited to the content of the embodiments shown below.

[0029] In addition, in the drawings and the like, the position, size, range, etc. of each component shown may not represent the actual position, size, range, etc. for the sake of easy understanding. For this reason, the disclosed invention is not necessarily limited to the position, size, range, etc. disclosed in the drawings and the like.

[0030] Also, in this specification and the like, ordinal numbers such as first, second, etc. are used for convenience, and may not indicate the process order or the stacking order. Therefore, for example, "the first" can be appropriately replaced with "the second" or "the third", etc. for explanation. Also, the ordinal numbers described in this specification and the like and the ordinal numbers used to specify an aspect of the present invention may not match.

[0031] Also, in this specification and the like, when explaining the configuration of the invention using the drawings, the same reference numerals may be commonly used among different drawings to indicate the same component.

[0032] Also, in this specification and the like, the term "film" and the term "layer" may be used interchangeably with each other. It is possible to replace. For example, the term "conductive layer" may be changed to the term "conductive film". Or, for example, the term "insulating film" may be changed to the term "insulating layer".

[0033] In addition, in this specification and the like, the singlet excited state (S * ) refers to the singlet state having excitation energy. Also, the S1 level is the lowest level of the singlet excitation energy levels, and it is the excitation energy level of the lowest singlet excited state. Also, the triplet excited state (T ) refers to the triplet state having excitation energy. Also, the T1 level is the lowest level of the triplet * excitation energy levels, and it is the excitation energy level of the lowest triplet excited state. In this specification and the like, even when simply referred to as the singlet excited state or the singlet excitation energy level, it may represent the lowest singlet excited state or the S1 level. Also, even when referred to as the triplet excited state or the triplet excitation energy level, it may represent the lowest triplet excited state or the T1 level.

[0034] In addition, in this specification and the like, a fluorescent material is a material that emits light in the visible light region when relaxing from the singlet excited state to the ground state. On the other hand, a phosphorescent material is a material that emits light in the visible light region at room temperature when relaxing from the triplet excited state to the ground state. In other words, a phosphorescent material is one of the materials that can convert triplet excitation energy into visible light.

[0035] Also, the phosphorescent emission energy or the triplet excitation energy is the shortest wavelength side of the phosphorescent emission. ​​​​​​​It can be derived from the wavelength of the emission peak (including the shoulder). The phosphorescence can be observed by performing a time-resolved photoluminescence method in a low-temperature environment (e.g., 10 K). In addition, the emission energy of the thermally activated delayed fluorescence can be derived from the wavelength of the emission peak (including the shoulder) on the shortest wavelength side of the thermally activated delayed fluorescence.

[0036] In this specification, etc., room temperature refers to any temperature from 0 °C to 40 °C.

[0037] In this specification, etc., the blue wavelength region is a wavelength region from 400 nm to less than 505 nm, and blue emission is emission having at least one emission spectrum peak in this wavelength region. In addition, the green wavelength region is a wavelength region from 505 nm to less than 580 nm, and green emission is emission having at least one emission spectrum peak in this wavelength region. In addition, the red wavelength region is a wavelength region from 580 nm to 680 nm, and red emission is emission having at least one emission spectrum peak in this wavelength region.

[0038] (Embodiment 1) In this embodiment, a light-emitting element according to one aspect of the present invention will be described below with reference to FIGS. 1 and 2.

[0039] <Configuration Example of Light-Emitting Element> First, the configuration of a light-emitting element according to one aspect of the present invention will be described below with reference to FIGS. 1(A) and (B).

[0040] FIG. 1(A) is a cross-sectional schematic view of a light-emitting element 150 according to one aspect of the present invention.

[0041] ​​​​​​​The light-emitting element 150 has a pair of electrodes (electrode 101 and electrode 102), and has an EL layer 100 provided between the pair of electrodes. The EL layer 100 has at least a light-emitting layer 130. .

[0042] Also, the EL layer 100 shown in FIG. 1(A) has functional layers such as a hole injection layer 111, a hole transport layer 112, an electron transport layer 118, and an electron injection layer 119 in addition to the light-emitting layer 130.

[0043] In this embodiment, among the pair of electrodes, electrode 101 is described as the anode and electrode 102 is described as the cathode. However, the configuration of the light-emitting element 150 is not limited to this. That is, electrode 101 may be the cathode and electrode 102 may be the anode, and the stacking order of the layers between the electrodes may be reversed. That is, from the anode side, the hole injection layer 111, the hole transport layer 112, the light-emitting layer 130, the electron transport layer 118, and the electron injection layer 119 may be stacked in this order. .

[0044] Note that the configuration of the EL layer 100 is not limited to the configuration shown in FIG. 1(A), and may have at least one selected from the hole injection layer 111, the hole transport layer 112, the electron transport layer 118, and the electron injection layer 119. Alternatively, the EL layer 100 may have a functional layer having a function such as reducing a hole or electron injection barrier, improving hole or electron transportability, inhibiting hole or electron transportability, or suppressing a quenching phenomenon caused by an electrode. Note that each functional layer may be a single layer or may have a structure in which a plurality of layers are stacked.

[0045] FIG. 1(B) is a cross-sectional schematic view showing an example of the light-emitting layer 130 shown in FIG. 1(A). FIG. 1( The light-emitting layer 130 shown in (B) has a host material 131 and a guest material 132. Also the host material 131 has an organic compound 131_1 and an organic compound 131_2.

[0046] Also, as the guest material 132, a light-emitting organic material may be used, and the light-emitting organic material is preferably a material that can emit phosphorescence (hereinafter also referred to as a phosphorescent material). In the following description, a configuration using a phosphorescent material as the guest material 132 will be described. Note that the guest material 132 may be read as a phosphorescent material.

[0047] <Light-emitting mechanism of the light-emitting element> Next, the light-emitting mechanism of the light-emitting layer 130 will be described below.

[0048] The organic compounds 131_1 and 131_2 included in the host material 131 in the light-emitting layer 130 form an exciplex (also referred to as an exciplex, an exiplex, or an Excipl ex).

[0049] The combination of the organic compound 131_1 and the organic compound 131_2 may be any combination that can form an exciplex, but it is more preferable that one has a function of transporting holes (hole-transporting property) and the other has a function of transporting electrons (electron-transporting property). In this case, it becomes easier to form a donor-acceptor type exciplex, and an exciplex can be efficiently formed.

[0050] Also, as the combination of the organic compound 131_1 and the organic compound 131_2, one is the highest occupied molecular orbital (Highest Occupied Molecular Orb It preferably has a HOMO level lower than the level (also referred to as HOMO) of the other, and a LUMO level lower than the level of the lowest unoccupied molecular orbital (also referred to as LUMO) of the other. Lowest Unoccupied Molecular Orbital, LU MO).

[0051] For example, as shown in the energy band diagram of FIG. 2(A), when the organic compound 131_1 has electron transportability and the organic compound 131_2 has hole transportability, the HOMO level of the organic compound 131_1 is lower than the HOMO level of the organic compound 131_2, and the LUMO level of the organic compound 1 31_1 is preferably lower than the LUMO level of the organic compound 131_2.

[0052] In this case, the exciplex formed by the organic compound 131_1 and the organic compound 131_2 has an excitation energy substantially corresponding to the energy difference (ΔE ) between the LUMO level of the organic compound 131_1 and the HOMO level of the organic compound 131_2. Ex

[0053] Further, the difference between the HOMO level of the organic compound 131_1 and the HOMO level of the organic compound 131_2, and the difference between the LUMO level of the organic compound 131_1 and the LUMO level of the organic compound 131_2 are each preferably 0.1 eV or more, more preferably 0.2 eV or more. By having such an energy difference, the electron carriers and hole carriers injected from a pair of electrodes (electrode 101 and electrode 102) are preferably easily injected into the organic compound 131_1 and the organic compound 131_2, respectively.

[0054] In FIG. 2(A), Host(131_1) represents the organic compound 131_1. Host(131_2) represents the organic compound 131_2, and Guest(132) represents the guest material 132, and ΔE Ex represents the energy difference between the LUMO level of the organic compound 131_1 and the HOMO level of the organic compound 131 _2. ΔE B represents the energy difference between the LUMO level of the organic compound 131_1 and the HOMO level of the guest material 132. ΔE G represents the energy difference between the LUMO level and the HOMO level of the guest material 1 32, which is a notation and symbol.

[0055] For the guest material 132 to exhibit emission with a short emission wavelength and high emission energy , it is preferable that the energy difference (ΔE G ) between the LUMO level and the HOMO level of the guest material 132 is large. On the other hand, in the light-emitting element 150, in order to reduce the driving voltage , it is preferable to excite with an excitation energy as small as possible. For this purpose, the excitation energy of the exciplex formed by the organic compound 131_1 and the organic compound 131_2 should be small . Therefore, the energy difference (ΔE ) between the LUMO level of the organic compound 131_1 and the HOMO level of the organic compound 13 Ex 1_2 is preferably small.

[0056] Note that since the guest material 132 is a phosphorescent light-emitting material, it has a function of converting triplet excitation energy into light emission . Also, the triplet excited state is more stable in energy than the singlet excited state. Therefore, the guest material 132 can exhibit emission with an energy smaller than the energy difference (ΔE ) between the LUMO level and the HOMO level. Here, the energy difference (ΔE G ) between the LUMO level and the HOMO level of the guest material 132 ​G ) is organically The energy difference between the LUMO level of organic compound 131_1 and the HOMO level of organic compound 131_2 (ΔE Ex ) Even when it is larger, the energy of the emission exhibited by guest material 132 ( Abbreviation: ΔE Em ) or the transition energy calculated from the absorption edge in the absorption spectrum (Abbreviation: ΔE abs ) is ΔE Ex If it is equal to or smaller, from the exciplex formed by organic compound 13 1_1 and organic compound 131_2, the transfer of excitation energy to guest material 132 becomes possible, and the inventors have found that light emission can be obtained from guest material 132. When ΔE of guest material 132 is greater than the energy of the emission exhibited by guest material 132 (ΔE ) or the transition energy (ΔE G ) calculated from the absorption edge in the absorption spectrum, a large amount of electrical energy corresponding to ΔE is required to directly electrically excite guest material 132, so the driving voltage of the light-emitting device increases. Em ) However, in one aspect of the present invention, the exciplex is electrically excited by electrical energy corresponding to ΔE (smaller than ΔE abs ), and the excited state of guest material 132 is generated by energy transfer from the exciplex. Therefore, light emission from guest material 132 can be obtained at a low driving voltage and with high efficiency. That is, when ΔE G is smaller than the energy of the emission exhibited by guest material 132 (ΔE ), or the transition energy calculated from the absorption spectrum (ΔE Ex (ΔE G smaller than ΔE ), the exciplex is electrically excited by electrical energy corresponding to ΔE and the excited state of guest material 132 is generated by energy transfer from the exciplex. Therefore, light emission from guest material 132 can be obtained at a low driving voltage and with high efficiency. That is, when ΔE is smaller than the energy of the emission exhibited by guest material 132 (ΔE G ) or the transition energy calculated from the absorption spectrum (ΔE ), or the transition energy (ΔE Em ) calculated from the absorption spectrum (ΔE abs When it is much larger than (for example, when the guest material is a blue light-emitting material), one aspect of the present invention

[0057] When the guest material 132 has a heavy metal, spin-orbit interaction (interaction between the spin angular momentum of electrons and the orbital angular momentum) promotes the intersystem crossing between the singlet state and the triplet state Therefore, the transition between the singlet ground state and the triplet excited state in the guest material 132 may not be forbidden That is, the efficiency of light emission and the probability of absorption related to the transition between the singlet ground state and the triplet excited state of the guest material 132 can be increased. Therefore, the guest material 132 preferably has a metal element with a large spin-orbit interaction, particularly a platinum group element (ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (O s), iridium (Ir), or platinum (Pt)), and preferably has iridium in particular. By having iridium the probability of absorption related to the direct transition between the singlet ground state and the triplet excited state can be increased, which is preferable.

[0058] In addition, in order for the guest material 132 to exhibit light emission with high emission energy (short wavelength), it is preferable that the lowest triplet excitation energy level of the guest material 132 is high. Therefore, as the ligand coordinating to the heavy metal atom contained in the guest material 132, it is also preferable that the lowest triplet excitation energy level is high, and it is preferable that the electron accepting property is low and the LUMO level is high

[0059] The guest material having the above structure is likely to have a molecular structure with a high HOMO level and easy to accept holes. When the guest material 132 has a molecular structure that easily accepts holes, the guest The HOMO level of the material 132 may be higher than the HOMO level of the organic compound 131_2. Furthermore, ΔE G is ΔE Ex If the LUMO level of the guest material 132 is greater than The LUMO level of the guest material 132 is higher than that of the organic compound 131_1. The energy difference between the LUMO level of the guest material 132 and the LUMO level of the organic compound 131_1 is The energy difference between the HOMO level of the organic compound 131_2 and that of the HOMO level of the organic compound 131_2 becomes larger. do.

[0060] Here, the HOMO level of the guest material 132 is higher than the HOMO level of the organic compound 131_2. The LUMO level of the guest material 132 is higher than that of the organic compound 131_1. When the charge transport rate is high, the carriers (holes and Among the electrons and the positive holes injected from the anode, the positive holes are transported to the guest material 132 in the light-emitting layer 130. The electrons injected from the cathode are easily injected into the organic compound 131_1. Therefore, among the materials contained in the light-emitting layer 130, the material having the highest HOMO level is the guest material 132, and the material with the lowest LUMO level is the organic compound 131_1 In this case, the organic compound 131_1 and the guest material 132 form an exciplex. In particular, the LUMO level of the organic compound 131_1 and the HOMO level of the guest material 132 Energy difference between the levels (abbreviation: ΔE B ) is the emission energy of the guest material (ΔE Em ) As the excitation current formed between the organic compound 131_1 and the guest material 132 becomes smaller than the excitation current In this case, the excited state is not generated by the guest material 132 alone. In order to aggregate, the luminous efficiency of the light-emitting element decreases.

[0061] The above reaction can be represented by the following formula (G11) or (G12).

[0062] A - +G + → (A·G) * (G11) A+G * → (A·G) * (G12)

[0063] Formula (G11) is a reaction in which the organic compound 131_1 receives an electron (A - ), and the guest material 132 receives a hole (G + ), thereby generating an excited complex ((A·G) ) of the organic compound 131_1 and the guest material 132. Further, formula (G12) is a reaction in which the excited guest material 132 (G * ) interacts with the ground-state organic compound 131_1 (A), thereby generating an excited complex ((A·G) ) of the organic compound 131_1 and the guest material 132. By forming an excited complex ((A·G) * ) between the organic compound 131_1 and the guest material 132, it becomes difficult to generate the excited state (G ) of the guest material 132 alone. * ) is generated . When the organic compound 131_1 and the guest material 132 form an excited complex ((A·G) * ), it becomes difficult to generate the excited state (G * ) of the guest material 132 alone. and ends up.

[0064] The excited complex formed by the organic compound 131_1 and the guest material 132 is an excited complex having an excitation energy generally corresponding to the energy difference (ΔE ) between the LUMO level of the organic compound 131 B ) and the HOMO level of the guest material 132. However, the energy difference (ΔE ) between the LUMO level of the organic compound 131 _1 and the HOMO level of the guest material 132. B) is , when the energy of the emission (ΔE Em ) or the transition energy (ΔE ) calculated from the absorption edge in the absorption spectrum of the guest material 132 is equal to or higher than that, the reaction of forming an exciplex between the organic compound 1 abs 31_1 and the guest material 132 can be suppressed, and the inventors have found that efficient light emission can be obtained from the guest material 132. In this case, since ΔE is smaller than ΔE , the guest material 132 easily receives excitation energy B and it is more energy-efficient and stable for the guest material 132 to receive the excitation energy and enter the excited state than to form an exciplex with the organic compound 131_1. abs As described above, even when the energy difference (Δ E ) between the LUMO level and the HOMO level of the guest material 132 is larger than the energy difference (ΔE

[0065] ) between the LUMO level of the organic compound 131_1 and the HOMO level of the organic compound 131_2, if the transition energy (ΔE E G ) calculated from the absorption edge in the absorption spectrum of the guest material 132 is equal to or smaller than ΔE , the excitation energy can be efficiently transferred from the exciplex formed between the organic compound 131_1 and the organic compound 131_2 to the guest material 132. As a result, one of the features of one aspect of the present invention is that a light-emitting device with low voltage and high efficiency can be obtained. Ex In this case, ΔE abs ≦ΔE Ex and is equal to or smaller than ΔE <ΔE (ΔE is less than or equal to ΔE and Δ abs E Ex <ΔE G (ΔE abs is less than or equal to ΔE Ex and Δ EEx is ΔE G is smaller). Therefore, ΔE abs is ΔE G is smaller than In the case where it is, the mechanism of one aspect of the present invention is suitable. In other words, ΔE G is ΔE abs more larger, the mechanism of one aspect of the present invention is suitable. More specifically, the guest material The energy difference (ΔE G ) between the LUMO level and the HOMO level of 132 is the transition energy (ΔE ) calculated from the absorption edge in the absorption spectrum of the guest material 13 abs ) by, It is preferably 0.3 eV or more larger, and more preferably 0.4 eV or more larger. Also, the energy (ΔE ) of the light emission exhibited by the guest material 132 is ΔE Em is equivalent to or smaller than that of ΔE abs Therefore, the energy difference (ΔE ) between the LUMO level and the HOMO level of the guest material 132 is the energy (ΔE G ) of the light emission exhibited by the guest material 132, by 0.3 eV or more larger Em It is preferably large, and more preferably 0.4 eV or more larger. Note that the energy of light emission (ΔE ) can be derived from the wavelength of the light emission peak (including the maximum value or shoulder) on the shortest wavelength side of the emission spectrum. Em ) can be derived from the wavelength of the light emission peak (including the maximum value or shoulder) on the shortest wavelength side of the emission spectrum. including) of the emission spectrum.

[0066] Furthermore, when the HOMO level of the guest material 132 is higher than the HOMO level of the organic compound 131_2, as described above, ΔE ≦ΔE abs ≦ΔE B (ΔE abs is ΔE B or less), or ΔE Em ≦ΔE B (ΔE Em is ΔE Bis preferably as follows. Therefore, ΔE abs ≦ΔE B <ΔE Ex <ΔE G (ΔE abs is ΔE B or less, and ΔE B is ΔE Ex smaller than and ΔE Ex is ΔE G smaller than, or ΔE Em ≦ΔE B <ΔE Ex <ΔE G ( ΔE Em is ΔE B or less, and ΔE B is ΔE Ex smaller than, and ΔE Ex is ΔE G smaller than is preferable. These conditions are also important findings in one aspect of the present invention.

[0067] Note that as the emission wavelength of the guest material 132 becomes shorter and the emission energy (ΔE Em ) increases, the energy difference (Δ E E G ) between the LUMO level and the HOMO level of the guest material 132 increases. Accordingly, a larger energy is required to electrically excite the guest material 132. However, in one aspect of the present invention, the transition energy (ΔE ) calculated from the absorption edge in the absorption spectrum of the guest material 132 is equal to or smaller than ΔE abs . If so, the guest material 132 can be excited with an energy of ΔE Ex which is smaller than ΔE G . Therefore, the power consumption of the light-emitting device can be reduced Ex to the extent of ΔE . Accordingly, the power consumption of the light-emitting device can be reduced because the guest material 132 can be excited with an energy smaller than ΔE The transition energy (ΔE abs ), the energy difference (ΔE ) between the LUMO level and the HOMO level of the guest material 132, and the energy difference is preferably larger (i.e., particularly in the case of a guest material exhibiting blue G luminescence), so that the effect of the mechanism of one aspect of the present invention becomes remarkable. .

[0068] However, when the transition energy (ΔE ) calculated from the absorption edge in the absorption spectrum of the guest material 132 becomes small, the energy of the luminescence exhibited by the guest material 132 also becomes small abs , so that it becomes difficult to obtain luminescence having a high energy such as blue luminescence. That is, if the difference between ΔE and ΔE abs becomes too large, it becomes difficult to obtain luminescence having a high energy such as blue luminescence. G

[0069] From these facts, the energy difference (ΔE G ) between the LUMO level and the HOMO level of the guest material 132 is preferably larger than the transition energy (ΔE ) calculated from the absorption edge in the absorption spectrum of the guest material 132 in the range of 0.3 eV or more and 0.8 eV or less, abs more preferably in the range of 0.4 eV or more and 0.8 eV or less, and even more preferably in the range of 0.5 eV or more and 0.8 eV or less. Further, since the energy of the luminescence (ΔE ) exhibited by the guest material 132 is equal to or smaller than ΔE , the energy difference (ΔE Em ) between the LUMO level and the HOMO level of the guest material 132 is the energy of the luminescence (ΔE abs ) exhibited by the guest material 132 or less. Therefore, the energy difference (ΔE G ) between the LUMO level and the HOMO level of the guest material 132 is the energy of the luminescence (ΔE ) exhibited by the guest material 132 EmTherefore, it is large in the range of 0.3 eV or more and 0.8 eV or less. It is preferably large in the range of 0.4 eV or more and 0.8 eV or less, more preferably large in the range of 0.5 eV or more and 0.8 eV or less, and even more preferably large in the range of 0.5 eV

[0070] In addition, the difference between the HOMO level of the guest material 132 and the HOMO level of the organic compound 131_2 is preferably 0.05 eV or more and 0.4 eV or less. An appropriate hole trap brings about the effect of extending the lifetime of the light-emitting element. However, if the HOMO level of the guest material is too high, the above-mentioned ΔE B becomes small. In addition, the difference between the LUMO level of the guest material 132 and the LUMO level of the organic compound 131_1 is preferably 0.05 eV or more, more preferably 0.1 eV or more, and even more preferably 0.2 eV or more. By setting such a correlation of energy levels, it is suitable because the injection of electron carriers into the organic compound 131_1 is reduced.

[0071] In addition, the energy difference (ΔE ) between the LUMO level of the organic compound 131_1 and the HOMO level of the organic compound 131_2 is Ex smaller than the energy difference between the LUMO level and the HOMO level of the organic compound 131_1 and the energy difference between the LUMO level and the HOMO level of the organic compound 131_2, respectively. Therefore, it is more energetically stable to form an exciplex than for the organic compounds 131_1 and 131_2 to form an excited state alone. Also In addition, the energy difference (ΔE G ) between the LUMO level and the HOMO level of the guest material 132 is smaller than the energy difference (ΔE Ex), the carriers (holes and electrons) injected into the light-emitting layer 130 The excited state formed by recombination is organic compound 131_1 and organic compound 131_2. The exciplex formed by the above is energetically stable. Most of the excited states are formed by organic compounds 131_1 and 131_2. Therefore, according to one embodiment of the present invention, By facilitating the transfer of excitation energy from the exciplex to the guest material 132, The driving voltage of the optical element can be reduced, and the light emission efficiency can be increased.

[0072] The LUMO level of the guest material 132 is lower than that of the organic compound 131_2. It can be high or low.

[0073] In addition, the HOMO level of the guest material 132 is higher than that of the organic compound 131_1. Since the guest material 132 has a high conductivity, it functions as a hole trap in the light-emitting layer 130. When the guest material 132 functions as a hole trap, the carrier balance in the light-emitting layer is This is preferable because it is possible to easily control the amount of oxygen that can be absorbed, and the effect of extending the life of the material can be obtained.

[0074] In addition, the combination of organic compound 131_1 and organic compound 131_2 has hole transport properties. In the case of a combination of a compound having a property of electron transport and a compound having a property of electron transport, the mixing ratio Specifically, the carrier balance can be easily controlled by using a hole transporting material. The weight ratio of the compound having an electron transporting property to the compound having an electron transporting property is preferably in the range of 1:9 to 9:1. In addition, by having this configuration, the carrier balance can be easily controlled. , the control of the carrier recombination region can also be easily performed.

[0075] The exciplex formed by the organic compound 131_1 and the organic compound 131_2 has a HOMO molecular orbital in one organic compound and a LUMO molecular orbital in the other organic compound. Therefore, the overlap between the HOMO molecular orbital and the LUMO molecular orbital is extremely small. That is, the exciplex has a small difference between the singlet excitation energy level and the triplet excitation energy level. Therefore, the exciplex formed by the organic compound 131_1 and the organic compound 131_2 preferably has a difference between the singlet excitation energy level and the triplet excitation energy level that is greater than 0 eV and less than or equal to 0.2 eV, more preferably greater than 0 eV and less than or equal to 0.1 eV.

[0076] Here, the energy level correlation among the organic compound 131_1, the organic compound 131_2, and the guest material 132 in the light-emitting layer 130 is shown in FIG. 2(B). Note that the notations and symbols in FIG. 2(B) are as follows. ·Host(131_1): Host material (organic compound 131_1) ·Host(131_2): Host material (organic compound 131_2) ·Guest(132): Guest material 132 (phosphorescent material) ·Exciplex: Exciplex (organic compound 131_1 and organic compound 131_2) ·S PH1 : S1 level of the host material (organic compound 131_1) ·T PH1 : T1 level of the host material (organic compound 131_1) ·S PH2 : S1 level of the host material (organic compound 131_2) ·T PH2 : T1 level of the host material (organic compound 131_2) ·S PG: S1 level of guest material 132 (phosphorescent material) ·T PG : T1 level of guest material 132 (phosphorescent material) ·S PE : S1 level of exciplex ·T PE : T1 level of exciplex

[0077] In the light-emitting element according to one aspect of the present invention, an organic compound 131_1 included in the light-emitting layer 130 and an organic compound 131_2 form an exciplex. The S1 level (S PE ) of the exciplex and the T1 level (T PE ) of the exciplex are adjacent to each other (see Route E7 in FIG. 2(B)) .

[0078] An exciplex is an excited state composed of two kinds of substances. In the case of photoexcitation, it is formed by the interaction of one substance in the excited state with the other substance in the ground state. Then, when it returns to the ground state by emitting light, the two substances that formed the exciplex behave as the original separate substances again. In the case of electrical excitation, when one becomes excited, it quickly forms an exciplex by interacting with the other. Alternatively, an exciplex can be quickly formed when one receives a hole and the other receives an electron. In this case, since an exciplex can be formed without either substance forming an excited state alone, most of the excited states in the light-emitting layer 130 can exist as an exciplex. The excitation energy levels (S and T ) of the exciplex are lower than the S1 levels (S and S ) of the host materials (organic compounds 131_1 and organic compound 131_2) that form the exciplex . Since an exciplex can be formed without either substance forming an excited state alone, most of the excited states in the light-emitting layer 130 can exist as an exciplex. The excitation energy levels (S and T E ) of the exciplex are lower than the S1 levels (S E ) of the host materials (organic compounds 131_1 and organic compound 131_2) that form the exciplex . The excitation energy levels (S PH1 and S PH2 ) of the host materials (organic compounds 131_1 and organic compound 131_2) that form the exciplex Since it becomes lower, it is possible to form an excited state of the host material 131 with a lower excitation energy. As a result, the driving voltage of the light-emitting element 150 can be reduced.

[0079] And the energies of both the singlet (S PE ) and triplet (T PE ) of the exciplex are transferred to the T1 level (T )(phosphorescent material) of the guest material 132 to obtain light emission (see Routes E8 PG ) and E9 in Fig. 2(B)). )

[0080] Note that the T1 level (T PE ) of the exciplex is preferably higher than the T1 level (T PG ) of the guest material 132. By having such a relationship of T1 levels, the singlet excitation energy and triplet excitation energy of the generated exciplex can be transferred from the S1 level (S ) and T1 level (T PE ) of the exciplex to the T1 level (T ) of the guest material 132. PE ) to the T1 level (T PG ) of the guest material 132. )

[0081] By configuring the light-emitting layer 130 as described above, it becomes possible to efficiently obtain light emission from the guest material 132 (phosphorescent material ) of the light-emitting layer 130.

[0082] Note that the processes of Route E7, Route E8, and Route E9 shown above may be referred to as ExTET (Exciplex-Triplet Energy Transfer ) in this specification and the like. In other words, in the light-emitting layer 130, there is donation of excitation energy from the exciplex to the guest material 132 . Also, in this case, it is not always necessary for the reverse intersystem crossing efficiency from T to S PE to be high, and the S PE to S crossing efficiency is not necessarily high, and the S PESince it is not necessary for the photoluminescence quantum yield from to be high, a wide range of materials can be selected.

[0083] Incidentally, the above reactions can be represented by the following formulas (G13) to (G15).

[0084] D + +A - → (D·A) * (G13) (D·A) * +G → D+A+G * (G14) G * → G+hν (G15)

[0085] Formula (G13) is a reaction in which one of the organic compounds 131_1 and 131_2 accepts a hole (D ), and the other accepts an electron (A + ), thereby generating an exciplex ((D·A) - ) between the organic compounds 131_1 and 131_2. Further, formula (G1 * 4) is a reaction in which energy transfer occurs from the exciplex ((D·A) ) to the guest material 132 (G), generating an excited state (G * ) of the guest material 132. Thereafter, as shown in formula (G15) , light emission (hν) occurs from the excited guest material 132. * In order to efficiently transfer the excitation energy from the exciplex to the guest material 132,

[0086] it is preferable that the T1 level (T ) of the exciplex is lower than the T1 levels of each of the organic compounds (organic compounds 131_1 and 131_2) constituting the host material forming the exciplex. PE This enables quenching of the triplet excitation energy of the exciplex by each organic compound. The occurrence of inches is reduced, and efficient energy transfer to the guest material 132 occurs.

[0087] Also, when the organic compound 131_2 has a strongly donor-like skeleton, holes injected into the light-emitting layer 130 are easily injected into and transported through the organic compound 131_2. Further, when the organic compound 131_1 has a strongly acceptor-like skeleton, electrons injected into the light-emitting layer 130 are easily injected into and transported through the organic compound 131_1. When electrons are injected into the organic compound 131_1 and holes are injected into the organic compound 131_2, respectively, it becomes easier for the organic compound 131_1 and the organic compound 131_2 to form an exciplex.

[0088] By configuring the light-emitting layer 130 as described above, efficient light emission from the guest material 132 of the light-emitting layer 130 can be obtained.

[0089] <Energy Transfer Mechanism> Next, the governing factors of the intermolecular energy transfer process between the host material 131 and the guest material 132 will be described. As the mechanism of intermolecular energy transfer, two mechanisms, the Förster mechanism (dipole-dipole interaction) and the Dexter mechanism (electron exchange interaction), have been proposed. Here, the intermolecular energy transfer process between the host material 131 and the guest material 132 will be described, but the same applies when the host material 131 is an exciplex.

[0090] ≪Förster Mechanism≫ In the Förster mechanism, energy transfer does not require direct contact between molecules, and energy transfer occurs through the resonance phenomenon of dipole vibrations between the host material 131 and the guest material 132. Due to the resonance phenomenon of dipole vibrations, the host material 131 transfers energy to the guest material 132 is transferred, the excited host material 131 returns to the ground state, and the ground state guest material 13 2 becomes excited. The rate constant k of the Förster mechanism is shown in Equation (1) h*→g as shown in Equation (1). .

[0091]

Equation

[0092] In Equation (1), ν represents the frequency, and f’ h (ν) represents the normalized emission spectrum of the host material 131 (fluorescence spectrum when discussing energy transfer from the singlet excited state, phosphorescence spectrum when discussing energy transfer from the triplet excited state), ε (ν) represents the molar extinction coefficient of the guest material 132, N represents Avogadro's number, n g represents the refractive index of the medium, R represents the intermolecular distance between the host material 131 and the guest material 132, τ represents the measured lifetime of the excited state (fluorescence lifetime or phosphorescence lifetime), c represents the speed of light, φ represents the emission quantum yield (fluorescence quantum yield when discussing energy transfer from the singlet excited state, phosphorescence quantum yield when discussing energy transfer from the triplet excited state), and K is a coefficient (ranging from 0 to 4) representing the orientation of the transition dipole moments of the host material 131 and the guest material 132. In the case of random orientation, K 2 is 2 / 3. 2 = 2 / 3.

[0093] ≪Dexter mechanism≫ In the Dexter mechanism, the host material 131 and the guest material 132 approach the contact effective distance where orbital overlap occurs, and the electron of the excited host material 131 and the ground state guest material 13 Energy transfer occurs through the exchange of electrons with 2. The rate constant k of the Dexter mechanism is shown in Equation (2). h*→g is shown in Equation (2).

[0094]

Equation

[0095] In Equation (2), h is the Planck constant, K is a constant with the dimension of energy and ν represents the frequency, f’ h (ν) represents the normalized emission spectrum of the host material 131 (fluorescence spectrum when discussing energy transfer from the singlet excited state, phosphorescence spectrum when discussing energy transfer from the triplet excited state). When discussing energy transfer from the singlet excited state, it is the fluorescence spectrum; when discussing energy transfer from the triplet excited state, it is the phosphorescence spectrum), ε’ When discussing energy transfer from the triplet excited state, it is the phosphorescence spectrum), ε’ g (ν) is , represents the normalized absorption spectrum of the guest material 132, L represents the effective molecular radius, R represents the intermolecular distance between the host material 131 and the guest material 132.

[0096] Here, the energy transfer efficiency φ from the host material 131 to the guest material 132 ET is represented by Equation (3). k r represents the rate constant of the emission process of the host material 131 (fluorescence when discussing energy transfer from the singlet excited state, phosphorescence when discussing energy transfer from the triplet excited state). When discussing energy transfer from the singlet excited state, it is fluorescence; when discussing energy transfer from the triplet excited state, it is phosphorescence), k phosphorescence), k n represents the rate constant of the non-emission process (thermal deactivation or intersystem crossing) of the host material 131. τ represents the measured lifetime of the excited state of the host material 131.

[0097]

Equation

[0098] From Equation (3), the energy transfer efficiency φET To increase it, the rate constant k of energy transfer should be increased, and the other competing rate constants k should be relatively small compared to k h*→g +k r +k n (=1 / τ). It can be seen that this is sufficient.

[0099] ≪Concepts for enhancing energy transfer≫ In energy transfer by the Förster mechanism, the energy transfer efficiency φ ET is preferably higher when the quantum yield φ of the species (fluorescence quantum yield when discussing energy transfer from the singlet excited state, phosphorescence quantum yield when discussing energy transfer from the triplet excited state) is higher. Also, it is preferable that the overlap between the emission spectrum of the host material 131 (fluorescence spectrum when discussing energy transfer from the singlet excited state) and the absorption spectrum of the guest material 132 (absorption corresponding to the transition from the singlet ground state to the triplet excited state) is large. Furthermore, it is preferable that the molar absorption coefficient of the guest material 132 is also high. This means that the emission spectrum of the host material 131 overlaps with the absorption band that appears on the longest wavelength side of the absorption spectrum of the guest material 132. Moreover, in energy transfer by the Dexter mechanism, to increase the rate constant k it is better that the overlap between the emission spectrum of the host material 131 (fluorescence spectrum when discussing energy transfer from the singlet excited state, phosphorescence spectrum when discussing energy transfer from the triplet excited state) and the absorption spectrum of the guest material 132 (absorption corresponding to the transition from the singlet ground state to the triplet excited state) is large. Therefore, for the energy transfer efficiency

[0100] h*→g to be increased, it is better that the overlap between the emission spectrum of the host material 131 (fluorescence spectrum when discussing energy transfer from the singlet excited state, phosphorescence spectrum when discussing energy transfer from the triplet excited state) and the absorption spectrum of the guest material 132 (absorption corresponding to the transition from the singlet ground state to the triplet excited state) is large. Thus, for the energy transfer efficiency Optimization is achieved by the overlap between the emission spectrum of the host material 131 and the absorption band that appears on the longest wavelength side of the absorption spectrum of the guest material 132.

[0101] In addition, similar to the energy transfer from the host material 131 to the guest material 132, energy transfer from the exciplex to the guest material 132 also occurs through energy transfer by both the Förster mechanism and the Dexter mechanism.

[0102] Therefore, one aspect of the present invention provides a light-emitting device having organic compounds 131_1 and organic compounds 131_2 as a host material 131, which form an exciplex having a function as an energy donor capable of efficiently transferring energy to the guest material 132. The exciplex formed by the organic compounds 131_1 and the organic compounds 131_2 can be formed with an excitation energy lower than the excitation states of the organic compounds 131_1 and the organic compounds 131_2 alone. Therefore, the driving voltage can be reduced in the light-emitting device 150. Furthermore, in order to facilitate energy transfer from the singlet excitation energy level of the exciplex to the triplet excitation energy level of the guest material 132 serving as an energy acceptor, it is preferable that the emission spectrum of the exciplex and the absorption band that appears on the longest wavelength side (low energy side) of the absorption spectrum of the guest material 132 overlap. By establishing such a relationship between the emission spectrum and the absorption spectrum, the generation efficiency of the triplet excited state of the guest material 132 can be increased. In addition, since the exciplex generated in the light-emitting layer 130 has the characteristic that the singlet excitation energy level and the triplet excitation energy level are close to each other, the emission By overlapping the absorption band that appears on the longest wavelength side (low energy side) of the optical spectrum and the absorption spectrum of the guest material 132, it becomes possible to easily cause energy transfer from the triplet excitation energy level of the exciplex to the triplet excitation energy level of the guest material 13 2.

[0103] <Material> Next, the details of the components of the light-emitting device according to one aspect of the present invention will be described below.

[0104] ≪Light-emitting layer≫ In the light-emitting layer 130, the host material 131 is present in the largest amount by weight ratio, and the guest material 132 (phosphorescent material) is dispersed in the host material 131. The T1 level of the host material 131 ([[]] organic compound 131_1 and organic compound 131_2) of the light-emitting layer 130 is preferably higher than the T1 level of the guest material (guest material 132) of the light-emitting layer 130.

[0105] ≪Host material≫ As the organic compound 131_1, a material having higher electron transportability than holes can be used, and it is preferably a material having an electron mobility of 1×10 -6 cm 2 / Vs or more. As a material that easily accepts electrons (a material having electron transportability), a compound having a π-electron deficient heteroaromatic ring skeleton such as a nitrogen-containing heteroaromatic compound can be used, and a metal complex such as a zinc or aluminum-based metal complex can also be used. Specifically, a metal complex having a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand can be mentioned. In addition, oxadiazole derivatives, triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, phenanthroline derivatives, pyridine derivatives, bipy derivatives, etc. can be used. derivatives, dibenzoquinoxaline derivatives, phenanthroline derivatives, pyridine derivatives, bipy Examples of the compound include lysine derivatives, pyrimidine derivatives, triazine derivatives and the like.

[0106] Specifically, for example, tris(8-quinolinolato)aluminum(III) (abbreviation: Alq), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq3), bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq), etc., and metal complexes having a quinoline skeleton or a benzoquinoline skeleton can be mentioned. In addition, metal complexes having an oxazole-based or thiazole-based ligand such as bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ), etc. can also be used. Further, in addition to metal complexes, 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 9-[4-(4,5-diphenyl-4H-1,2,4-triazol-3-yl)phenyl]-9H-carbazole (abbreviation: CzT) can also be used.​​​​​​​​​​​​​​​AZ1), 2,2’,2’’-(1,3,5-benzenetriyl)tris(1-phenyl -1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen- 4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBI m-II), bathophenanthroline (abbreviation: BPhen), bathocuproine (abbreviation: B CP), and other heterocyclic compounds, 2-[3-(dibenzothiophen-4-yl)phenyl] dibenz[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3’-( dibenzothiophen-4-yl)biphenyl-3-yl]dibenz[f,h]quinoxali ne (abbreviation: 2mDBTBPDBq-II), 2-[3’-(9H-carbazol-9-yl yl)biphenyl-3-yl]dibenz[f,h]quinoxaline (abbreviation: 2mCzBPDB q), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]di dibenz[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(diben zothiophen-4-yl)phenyl]dibenz[f,h]quinoxaline (abbreviation: 7mDB TPDBq-II), and 6-[3-(dibenzothiophen-4-yl)phenyl]di dibenz[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 2-[3-(3, 9’-bi-9H-carbazol-9-yl)phenyl]dibenz[f,h]quinoxaline (abbreviation: 2mCzCzPDBq), 4,6-bis[3-(phenanthren-9-yl)f enyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-diben zothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6- bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mC Heterocyclic compounds having a diazine skeleton such as zP2Pm, and 2-{4-[3-(N-phen nyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}- Heterocyclic compounds having a triazine skeleton such as 4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), and 3,5-bis[3-(9H-carbazol-9-yl )phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyr )phenyl]benzene (abbreviation: TmPyPB) and other heterocyclic compounds having a pyridine skeleton, 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs) and other heteroaromatic compounds can also be used. Among the above-mentioned heterocyclic compounds also, heterocyclic compounds having a triazine skeleton, a diazine (pyrimidine, pyrazine, pyridazine) skeleton, or a pyr idine skeleton are preferred because they are stable and have good reliability. In addition, heterocyclic compounds having the skeleton have high electron transport properties and also contribute to reducing the driving voltage. Also, poly( 2,5-pyridinediyl) (abbreviation: PPy), poly[(9,9-dihexylfluorene- 2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviation: PF-Py), poly [(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine -6,6'-diyl)] (abbreviation: PF-BPy) and other polymer compounds can also be used. The substances described here mainly have an electron mobility of 1×10 cm / Vs or more. As long as the substance has higher electron transport properties than holes, substances other than the above can also be used. -6 cm 2 / Vs or more substances. Note that as long as the substance has higher electron transport properties than holes, substances other than the above can be used.

[0107] ​​As the organic compound 131_2, a combination capable of forming an exciplex with the organic compound 131_1 is preferred. Specifically, it preferably has a highly donor-like skeleton such as a π-electron-excessive heteroaromatic ring skeleton or an aromatic amine skeleton. As the compound having a π-electron-excessive heteroaromatic ring skeleton, heteroaromatic compounds such as dibenzothiophene derivatives, dibenzofuran derivatives, and carbazole derivatives can be mentioned. In this case, it is preferable to select the organic compound 131_1, the organic compound 131_2, and the guest material 132 (phosphorescent material) so that the emission peak of the exciplex formed by the organic compound 131_1 and the organic compound 131_2 overlaps with the absorption band of the triplet MLCT (Metal to Ligand Charge Transfer) transition of the guest material 132 (phosphorescent material), more specifically, the absorption band on the longest wavelength side. Thereby, a light-emitting device with a dramatically improved luminous efficiency can be obtained. However, when a thermally activated delayed fluorescence material is used instead of the phosphorescent material, it is preferable that the absorption band on the longest wavelength side is a singlet absorption band.

[0108] In addition, as the organic compound 131_2, the following hole-transporting materials can be used.

[0109] As the hole-transporting material, a material with higher hole transportability than electrons can be used, and it is preferably a material having a hole mobility of 1 × 10 cm -6 / Vs or more. 2 Specifically, aromatic amines, carbazole derivatives, aromatic hydrocarbons, stilbene derivatives, etc. can be used. In addition, the hole-transporting material may be a polymer compound.

[0110] As these materials with high hole transport properties, specifically, as aromatic amine compounds, N, N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DT DPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N'-bis{4-[bis(3-methylphenyl yl)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. can be mentioned. -diamine (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), etc. can be mentioned. can be mentioned. .

[0111] Also, as carbazole derivatives, specifically, 3-[N-(4-diphenylamino phenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA1 ), 3,6-bis[N-(4-diphenylaminophenyl)-N-phenylamino]-9 -phenylcarbazole (abbreviation: PCzDPA2), 3,6-bis[N-(4-diphenyl laminophenyl)-N-(1-naphthyl)amino]-9-phenylcarbazole (abbreviation : PCzTPN2), 3-[N-(9-phenylcarbazol-3-yl)-N-phenyl ylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N- (9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarb azole-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1) etc. can be mentioned. can be mentioned.

[0112] In addition, as the carbazole derivative, among others, 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB), 9-[4-(10-phenyl-9-anthracenyl)phenyl] -9H-carbazole (abbreviation: CzPA), 1,4-bis[4-(N-carbazolyl) phenyl]-2,3,5,6-tetraphenylbenzene and the like can be used.

[0113] In addition, as the aromatic hydrocarbon, for example, 2-tert-butyl-9,10-di(2- naphthyl)anthracene (abbreviation: t-BuDNA), 2-tert-butyl-9,10- di(1-naphthyl)anthracene, 9,10-bis(3,5-diphenylphenyl)anthra cene (abbreviation: DPPA), 2-tert-butyl-9,10-bis(4-phenylph enyl)anthracene (abbreviation: t-BuDBA), 9,10-di(2-naphthyl)anth racene (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-naphthyl)anthracene, 2,3,6,7-tetramethyl-9,10-di(2-naph thyl)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' -biantryl, anthracene, tetracene, rubrene, perylene, 2,5,8,11- tetra(tert-butyl)perylene, etc. may be mentioned. In addition, pentacene, coronene, etc. can also be used. Thus, a hole mobility of 1×10 cm -6 / Vs or more, and it is more preferable to use an aromatic hydrocarbon having 14 or more and 42 or less carbon atoms. 2

[0114] Incidentally, the aromatic hydrocarbon may have a vinyl skeleton. Examples of the aromatic hydrocarbon having a vinyl group include 4,4'-bis(2,2-diphenylvinyl)biphenyl (abbreviation: DPVBi), 9,10-bis[4-(2,2-diphenylvinyl)phenyl] anthracene (abbreviation: DPVPA), etc.

[0115] In addition, polymer compounds such as poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenyl amino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide]( (abbreviation: PTPDMA), poly[N,N'-bis(4-butylphenyl)-N,N'-bis (phenyl)benzidine] (abbreviation: Poly-TPD), etc. can also be used.

[0116] Furthermore, examples of materials with high hole transport properties include 4,4'-bis[N-(1-naphthyl l)-N-phenylamino]biphenyl (abbreviation: NPB or α-NPD), N,N'- ​​​​​​Bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4, 4'-diamine (abbreviation: TPD), 4,4',4''-tris(carbazol-9-yl )triphenylamine (abbreviation: TCTA), 4,4',4''-tris[N-(1-naph thyl)-N-phenylamino]triphenylamine (abbreviation: 1'-TNATA), 4,4 ',4''-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDAT A), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino] triphenylamine (abbreviation: MTDATA), 4,4'-bis[N-(spiro-9,9' -bifluorene-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4 -phenyl-4'-(9-phenylfluorene-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluorene-9-yl)triphenyl ylamine (abbreviation: mBPAFLP), N-(9,9-dimethyl-9H-fluorene-2 -yl)-N-{9,9-dimethyl-2-[N'-phenyl-N'-(9,9-dimethyl -9H-fluorene-2-yl)amino]-9H-fluorene-7-yl}phenylamine (abbreviation: DFLADFL), N-(9,9-dimethyl-2-diphenylamino-9H- fluorene-7-yl)diphenylamine (abbreviation: DPNF), 2-[N-(4-diphe nylaminophenyl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: DPASF), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9- phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1B P), 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: PCBN BB), 4-Phenyldiphenyl-(9-phenyl-9H-carbazol-3-yl)a mine (abbreviation: PCA1BP), N,N'-Bis(9-phenylcarbazol-3-yl) -N,N'-Diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N,N', N''-Triphenyl-N,N',N''-Tris(9-phenylcarbazol-3-yl yl)benzene-1,3,5-triamine (abbreviation: PCA3B), N-(4-Biphenyl) -N-(9,9-Dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-carb azole-3-amine (abbreviation: PCBiF), N-(1,1'-Biphenyl-4-yl) -N-[4-(9-Phenyl-9H-carbazol-3-yl)phenyl]-9,9-di methyl-9H-fluorene-2-amine (abbreviation: PCBBiF), 9,9-Dimethyl-N -phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]f luorene-2-amine (abbreviation: PCBAF), N-Phenyl-N-[4-(9-Phenyl -9H-carbazol-3-yl)phenyl]spiro-9,9'-bifluorene-2-a mine (abbreviation: PCBASF), 2-[N-(9-Phenylcarbazol-3-yl)-N -phenylamino]spiro-9,9'-bifluorene (abbreviation: PCASF), 2,7-bi s[N-(4-Diphenylaminophenyl)-N-phenylamino]spiro-9,9'- Bifluorene (abbreviation: DPA2SF), N-[4-(9H-carbazol-9-yl)phenyl]-N-(4-phenyl)phenylaniline (abbreviation: YGA1BP), N,N’- bis[4-(carbazol-9-yl)phenyl]-N,N’-diphenyl-9,9-dimethylfluorene-2,7-diamine (abbreviation: YGA2F) and other aromatic amine compounds, etc. can be used. Also, 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 3-[4-(9-phenanthryl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPPn), 3,3’-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP), 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), 3,6-di(9H-carbazol-9-yl)-9-phenyl-9H-carbazole (abbreviation: PhCzGI), 2,8-di(9H-carbazol-9-yl)-dibenzothiophene (abbreviation: Cz2DBT), 4-{3-[3-(9-phenyl-9H-fluorene-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), 4,4’,4’’-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), 1,3,5-tri(dibenzothiophen-4-yl)benzene (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), 4 such as these can be used. Moreover, 3-[4-(1-naphthyl)-phenyl]-9-phenyl -9H-carbazole (abbreviation: PCPN), 3-[4-(9-phenanthryl)-phenyl yl]-9-phenyl-9H-carbazole (abbreviation: PCPPn), 3,3’-bis(9- phenyl-9H-carbazole) (abbreviation: PCCP), 1,3-bis(N-carbazolyl )benzene (abbreviation: mCP), 3,6-bis(3,5-diphenylphenyl)-9-phen ylcarbazole (abbreviation: CzTP), 3,6-di(9H-carbazol-9-yl)- 9-phenyl-9H-carbazole (abbreviation: PhCzGI), 2,8-di(9H-carb azole-9-yl)-dibenzothiophene (abbreviation: Cz2DBT), 4-{3-[3-( 9-phenyl-9H-fluorene-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), 4,4’,4’’-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), 1,3,5-tri(dibenzothiophen-4-yl)benzene (abbreviation: DBT3P-II), 2,8-diphenyl-4 -[4-(9-phenyl-9H-fluorene-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluorene-9- yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), 4 -[4-(9-phenyl-9H-fluorene-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluorene-9- yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), 4 -[3-(Triphenylen-2-yl)phenyl]dibenzothiophene (abbreviation: mDBT amine compounds such as PTp-II), carbazole compounds, thiophene compounds, furan compounds compounds, fluorene compounds, triphenylene compounds, phenanthrene compounds, etc. can be used Among the above-mentioned compounds, compounds having a pyrrole skeleton, a furan skeleton, a thiophene skeleton, an aromatic amine skeleton are preferred because they are stable and have good reliability. Further, the compounds having such a skeleton have high hole transportability and contribute to reducing the driving voltage.

[0117] ≪Guest material≫ As the guest material 132 (phosphorescent material), iridium, rhodium, or platinum-based organic metal complexes, or metal complexes can be mentioned. Among them, organic iridium complexes, for example, iridium orthometal complexes are preferred. As the ligand for orthometalation, 4H-triazole ligand, 1H-triazole ligand, imidazole ligand, pyridine ligand, pyrimidine ligand, pyrazine ligand, or isoquinoline ligand, etc. can be mentioned. As the metal complex platinum complexes having a porphyrin ligand can be mentioned.

[0118] Further, as the guest material 132 (phosphorescent material), it has a LUMO level higher than the LUMO level of the organic compound 131_1 and a HOMO level higher than the HOMO level of the organic compound 131_2. It is preferable to select the organic compound 131_1, the organic compound 131_2, and the guest material 13 2 (phosphorescent material) accordingly. Thereby, a light-emitting element with high luminous efficiency and capable of being driven at a low voltage can be obtained.

[0119] ​​Examples of substances having a blue or green emission peak include tris{2-[5-(2 -methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazo {3-yl-κN2]phenyl-κC}iridium(III) (abbreviation: Ir(mpp tz-dmp)3), tris(5-methyl-3,4-diphenyl-4H-1,2,4-tris( riazolate)iridium(III) (abbreviation: Ir(Mptz)3), tris[4-(3- Biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]i Iridium(III) (abbreviation: Ir(iPrptz-3b)3), tris[3-(5-biphenyl] (phenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]irid Ir(III) (abbreviation: Ir(iPr5btz)3), a 4H-triazole skeleton and organometallic iridium complexes having tris[3-methyl-1-(2-methylphenyl) -5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: Ir (Mptz1-mp)3), tris(1-methyl-5-phenyl-3-propyl-1H- 1,2,4-Triazolate)iridium(III) (abbreviation: Ir(Prptz1-Me) 3) and fac-triazole-based organometallic iridium complexes. S[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole] Iridium(III) (abbreviation: Ir(iPrpmi)3), tris[3-(2,6-dimethyl phenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(I II) Imidazole skeleton-containing compounds such as Ir(dmpimpt-Me)3 Organic metal iridium complexes and bis[2-(4',6'-difluorophenyl)pyridinato N, C 2’ Iridium(III) tetrakis(1 - pyrazolyl)borate (abbreviation: FI r6), bis[2-(4’,6’-difluorophenyl)pyridinato - N,C 2’ Iri dium(III) picolinate (abbreviation: FIrpic), bis{2-[3’,5’-bis (trifluoromethyl)phenyl]pyridinato - N,C 2’}iridium(III) pico linate (abbreviation: Ir(CF3ppy)2(pic)), bis[2-(4’,6’-dif luorophenyl)pyridinato - N,C 2’ iridium(III) acetylacetonate (abbreviation: FIr(acac)) and other phenylpyridine derivatives having an electron - withdrawing group as a ligand include organometallic iridium complexes. Among those mentioned above, organometallic iridium complexes having a nitrogen - containing five - membered heterocyclic skeleton such as a 4H - triazole skeleton, 1H - triazole skeleton and imidazole skeleton have high triplet excitation energy and are particularly preferable because of their excellent reliability and luminescence efficiency .

[0120] In addition, substances having a luminescence peak in green or yellow include, for example, tris(4 - methyl -6 - phenylpyrimidinato)iridium(III) (abbreviation: Ir(mppm)3), tris(4 - t - butyl - 6 - phenylpyrimidinato)iridium(III) (abbreviation: I r(tBuppm)3), (acetylacetonato)bis(6 - methyl - 4 - phenylpyr imidinato)iridium(III) (abbreviation: Ir(mppm)2(acac)), (acetyl acetonato)bis(6 - tert - butyl - 4 - phenylpyrimidinato)iridium( III) (abbreviation: Ir(tBuppm)2(acac)), (acetylacetonato)bis [4-(2-Norbornanyl)-6-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-dimethyl -2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN3]phenyl- κC}iridium(III) (abbreviation: Ir(dmppm-dmp)2(acac)), ( acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) ( abbreviation: Ir(dppm)2(acac)) and other organometallic iri dium complexes having a pyrimidine skeleton, (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazina to)iridium(III) (abbreviation: Ir(mppr-Me)2(acac)), (acetyl acetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridi um(III) (abbreviation: Ir(mppr-iPr)2(acac)) and other organometallic iridium complexes having a pyrazine skel eton, 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(ac ac)), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: Ir(bzq)2(acac)), tris(benzo[h]quinolinato)iridi um(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(ac ac)) and other organometallic iridium complexes having a pyridine skeleton, bis(2,4-dif enyl-1,3-oxazolato-N,C 2’ ) Iridium(III) acetylacetonato (abbreviation: Ir(dpo)2(acac)), bis{2-[4’-(perfluorophen yl)phenyl]pyridinato-N,C 2’} Iridium(III) acetylacetonate( abbreviation: Ir(p-PF-ph)2(acac)), bis(2-phenylbenzothiazolato -N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(bt)2(a cac)) and other organometallic iridium complexes, tris(acetylacetonato)(monophen anthroline) terbium(III) (abbreviation: Tb(acac)3(Phen)) such as rare earth metal complexes are mentioned. Among the above, organometallic iri dium complexes having a pyrimidine skeleton are particularly preferred because of their outstanding reliability and luminescence efficiency.

[0121] Also, as substances having a luminescence peak in yellow or red, for example, (diisobutyryl methanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(II I) (abbreviation: Ir(5mdppm)2(dibm)), bis[4,6-bis(3-methyl phenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: Ir (5mdppm)2(dpm)), bis[4,6-di(naphthalen-1-yl)pyrimidin Sodium](dipivaloylmethanato)iridium(III) (abbreviation: Ir(d1npm)2( dpm)), organometallic iridium complexes having a pyrimidine skeleton such as, (acetylacet onato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviation: I r(tppr)2(acac)), bis(2,3,5-triphenylpyrazinato)(dip ivaloylmethanato)iridium(III) (abbreviation: Ir(tppr)2(dpm)), ( acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]i ridium(III) (abbreviation: Ir(Fdpq)2(acac)), organometallic iridium complexes having a pyrazine skeleton such as, tris(1-phenylisoquinolinato-N,C 2’ ) iridium(III) (abbreviation: 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-porphyrin platinum(II )(abbreviation: PtOEP), platinum complexes such as, tris(1,3-diphenyl-1,3-prop anedionato)(monophenanthroline)europium(III) (abbreviation: Eu(DB M)3(Phen)), tris[1-(2-thenoyl)-3,3,3-trifluoroac etonato)(monophenanthroline)europium(III) (abbreviation: Eu(TTA)3( Phen)) and other rare earth metal complexes can be mentioned. Among the above, organometallic iridium complexes having a pyrimidine skeleton are particularly preferable because they are outstanding in terms of reliability and luminescence efficiency. ​​Yes. In addition, an organometallic iridium complex having a pyrazine skeleton can obtain red light emission with good chromaticity. It can be obtained.

[0122] In addition, among the above-mentioned iridium complexes, organometallic iridium complexes having a nitrogen-containing five-membered heterocyclic skeleton such as a 4H-triazole skeleton, a 1H-triazole skeleton, and an imidazole skeleton, and iridium complexes having a pyridine skeleton have low electron accepting ability of the ligand and HOMO Since the level tends to be high, it is suitable for one aspect of the present invention. level is likely to be high, so it is suitable for one aspect of the present invention.

[0123] In addition, among the organometallic iridium complexes having a nitrogen-containing five-membered heterocyclic skeleton, an iridium complex having a substituent containing at least a cyano group has a moderate decrease in the LUM O level and HOMO level due to the strong electron-withdrawing property of the cyano group, so it can be suitably used for the light-emitting element of one aspect of the present invention. In addition, since the iridium complex has a high triplet excitation energy level, by using the iridium complex in a light-emitting element, a light-emitting element exhibiting good blue light with high luminous efficiency can be manufactured. In addition, since the iridium complex has good resistance to repeated oxidation and reduction, by using the iridium complex in a light-emitting element, a light-emitting element with good driving life can be manufactured.

[0124] From the viewpoints of stability and reliability of element characteristics, it is preferably an iridium complex having a ligand in which an aryl group containing a cyano group is bonded to the nitrogen-containing five-membered heterocyclic skeleton, and the carbon number of the aryl group is preferably 6 to 13. In this case, since the iridium complex can be vacuum-deposited at a relatively low temperature, deterioration such as thermal decomposition during deposition is unlikely to occur.

[0125] ​​​​​​In addition, a nitrogen atom in the nitrogen-containing five-membered heterocyclic skeleton is bonded to a cyano group via an arylene group. The iridium complex having a ligand in which a cyano group is bonded via an arylene group can keep the triplet excitation energy level high, and thus can be suitably used particularly for a light-emitting device that exhibits high-energy light emission such as blue light emission. In addition, compared with the case where it does not have a cyano group, a highly efficient light-emitting device can be obtained while showing high-energy light emission such as blue light emission. Furthermore, by introducing a cyano group at such a specific position, a highly reliable light-emitting device can be obtained while showing high-energy light emission such as blue light emission. There is also a feature that a highly reliable light-emitting device can be obtained while showing high-energy light emission such as blue light emission. Note that it is preferable that the nitrogen-containing five-membered heterocyclic skeleton and the cyano group are bonded via an arylene group such as a phenylene group. Note that it is preferable that the nitrogen-containing five-membered heterocyclic skeleton and the cyano group are bonded via an arylene group such as a phenylene group. There is also a feature that a highly reliable light-emitting device can be obtained while showing high-energy light emission such as blue light emission. Note that it is preferable that the nitrogen-containing five-membered heterocyclic skeleton and the cyano group are bonded via an arylene group such as a phenylene group.

[0126] When the number of carbon atoms of the arylene group is 6 to 13, the iridium complex becomes a compound having a relatively low molecular weight, and thus becomes a compound suitable for vacuum deposition (capable of being vacuum-deposited at a relatively low temperature). In general, when the molecular weight is low, the heat resistance after film formation tends to be poor. However, since the iridium complex has a plurality of ligands, even if the molecular weight of the ligand is low, there is an advantage that sufficient heat resistance can be ensured. Even if the molecular weight of the ligand is low, there is an advantage that sufficient heat resistance can be ensured.

[0127] That is, in addition to the ease of deposition and electrochemical stability described above, the iridium complex also has the characteristic that the triplet excitation energy level is high. Therefore, in a light-emitting device according to one embodiment of the present invention, it is preferable to use the iridium complex as a guest material in a light-emitting layer. Among them, it is more preferable to use it as a guest material for a blue light-emitting device. Among them, it is more preferable to use it as a guest material for a blue light-emitting device.

[0128] ≪Examples of iridium complex≫ The above iridium complex is an iridium complex represented by the following general formula (G1).

[0129]

Chem.

[0130] In the above general formula (G1), Ar 1 and Ar 2 each independently represents a substituted or unsubstituted aryl group having 6 to 1 3 carbon atoms. Specific examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. can be mentioned. When the aryl group has a substituent, the substituent can be selected from an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, etc. Also, specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, etc. Also, as the aryl group having 6 to 13 carbon atoms, a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. can be mentioned as specific examples. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, etc. Also, specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, etc. Also, as the aryl group having 6 to 13 carbon atoms, a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. can be mentioned as specific examples. Specific examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. can be mentioned as specific examples.

[0131] Also, Q 1 and Q 2 each independently represents N or C-R, and R represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Note that at least one of Q and Q is C-R 1 and Q 2 ​It has. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, etc. Further, examples of the haloalkyl group having 1 to 6 carbon atoms include an alkyl group in which at least one hydrogen is substituted by a Group 17 element (fluorine, chlorine, bromine, iodine, astatine), and include a fluoroalkyl group, a chloroalkyl group, a bromoalkyl group, an iodoalkyl group, etc. Specifically, a methyl fluoride group, a methyl chloride group, a fluoroethyl group, a chloroethyl group, etc. can be mentioned. However, the number or type of the halogen element contained may be one or plural. Further, specific examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. Furthermore, the aryl group may have a substituent, and the substituents may be bonded to each other to form a ring. Examples of the substituent include an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 13 carbon atoms. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, etc. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, etc. Specific examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. can be mentioned as specific examples.

[0132] ​​​​​​In addition, Ar 1 and Ar 2 represent an aryl group, and at least one of the aryl groups represented by R has a cyano group.

[0133] In addition, as the iridium complex that can be suitably used for the light-emitting element of one aspect of the present invention , it is preferably an orthometalated complex. The above iridium complex is represented by the following general formula (G2) is an iridium complex represented by the formula.

[0134]

Chemical formula

[0135] In the above general formula (G2), Ar 1 represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms -yl group. Specific examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. When the aryl group has a substituent , the substituent can be selected from an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms as a substituent group. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group yl group, an n-hexyl group, etc. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, etc. Specific examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. as specific examples can be mentioned. can be mentioned. can be mentioned.

[0136] Also, R 1 to R 4 each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, or a cyano group. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, and the like. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and the like. Specific examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, and the like that can be cited. Note that R to R are all hydrogen, which is advantageous in terms of ease of synthesis and raw material price. 1 to R 4 are all hydrogen, which is advantageous in terms of ease of synthesis and raw material price.

[0137] Also, Q 1 and Q 2 each independently represents N or C-R, and R represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Note that at least one of Q and Q has C-R 1 and Q 2 . Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, and the like. Specific examples of the haloalkyl group having 1 to 6 carbon atoms include at least one of the following: at least one hydrogen is replaced by a Group 17 element (fluorine, chlorine, bromine, iodine, astatine) to form an alkyl group, such as a fluorinated alkyl group, a chlorinated alkyl group, a brominated alkyl group, an iodinated alkyl group, etc., specifically, a methyl fluoride group, a methyl chloride group, a fluorinated ethyl group, a chlorinated ethyl group, etc. can be mentioned, and the number or type of halogen element contained may be one or more respectively. Further, as the aryl group having 6 to 13 carbon atoms, a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. can be specifically mentioned as examples. Further, the aryl group may have a substituent, and the substituents may be bonded to each other to form a ring. As the substituent, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 13 carbon atoms can also be selected as a substituent. Specifically, as the alkyl group having 1 to 6 carbon atoms, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, etc. can be mentioned. Further, specifically, as the cycloalkyl group having 3 to 6 carbon atoms, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, etc. can be mentioned. Further, as the aryl group having 6 to 13 carbon atoms a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. can be specifically mentioned as examples.

[0138] Also, Ar 1 and R 1 to R 4 the aryl group represented by, the aryl group represented by R, and R 1 to R 4 at least one of has a cyano group.

[0139] In addition, in an iridium complex that can be suitably used for the light-emitting element of one aspect of the present invention By having a 4H-triazole skeleton as a ligand, it can have a high triplet excitation energy level And it is particularly suitable for a light-emitting element that exhibits high-energy light emission such as blue light Therefore, it is preferable because it can be used. The above iridium complex is represented by the following general formula (G3) It is an iridium complex represented by the following general formula (G3).

[0140]

Chemical formula

[0141] In the above general formula (G3), Ar 1 Represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms Specific examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. When the aryl group has a substituent The substituent can be selected from an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, etc. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, etc. Specific examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. Can be mentioned. Can be mentioned. Can be mentioned. Group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-hexyl group, etc. can be mentioned. Also, as the cycloalkyl group having 3 to 6 carbon atoms, specifically, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, Cyclohexyl group, etc. can be mentioned. Also, as the aryl group having 6 to 13 carbon atoms, specifically, a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. can be mentioned as specific examples Can be mentioned. Can be mentioned. Can be mentioned. Can be mentioned.

[0142] Also, R 1 to R 4 each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, or a cyano group. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, and the like. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and the like. Specific examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, and the like which can be cited. Note that it is advantageous in terms of ease of synthesis and raw material cost that all of R to R are hydrogen. 1 to R 4 are all hydrogen, which is advantageous in terms of ease of synthesis and raw material cost.

[0143] Also, R 5 represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms , or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, and the like which can be cited. Specific examples of the haloalkyl group having 1 to 6 carbon atoms include an alkyl group in which at least one hydrogen is substituted by a Group 17 element (fluorine, chlorine, bromine, iodine, astatine), and include a fluoroalkyl group, a chloroalkyl group, a bromoalkyl group, an iodoalkyl group wherein the alkyl group has 1 to 6 carbon atoms. Specific examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, and the like Examples include, specifically, a methyl fluoride group, a methyl chloride group, an ethyl fluoride group, an ethyl chloride group, etc. Although examples thereof include a methyl fluoride group, a methyl chloride group, an ethyl fluoride group, an ethyl chloride group, etc., the number or type of halogen element contained may be either one or plural. Examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. can be specifically cited. Further, the aryl group may have a substituent, and the substituents may be bonded to each other to form a ring. Examples of the substituent include an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 13 carbon atoms can also be selected as the substituent. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, etc. can be cited. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, etc. can be cited. Examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. can be specifically cited.

[0144] Also, Ar 1 and R 1 to R 5 represent an aryl group, and at least one of R 1 to R 4 has a cyano group.

[0145] In addition, in the iridium complex that can be suitably used for the light-emitting element of one aspect of the present invention has a high triplet excitation energy level by having an imidazole skeleton as a ligand. It can be used suitably, especially for a light-emitting element that exhibits high-energy light emission such as blue light. This is possible, so it is preferable. The iridium complex is an iridium complex represented by the following general formula (G4).

[0146]

Chemical formula

[0147] In the above general formula (G4), Ar 1 represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. When the aryl group has a substituent, the substituent can be selected from an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, etc. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, etc. Specific examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc.

[0148] Also, R 1 to R 4 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a carbon number ​​​​​​​​​​​​A cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms is represented by any of them. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n -hexyl group and the like. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohex yl group and the like. Specific examples of the aryl group having 6 to 13 carbon atoms include a phen yl group, a naphthyl group, a biphenyl group, a fluorenyl group and the like. Note that R to R are all hydrogen, which is advantageous in terms of ease of synthesis and raw material price 1 to 4 .

[0149] In addition, R 5 and R 6 each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms haloalkyl group, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms . Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n- hexyl group and the like. Specific examples of the haloalkyl group having 1 to 6 carbon atoms include an alkyl group in which at least one hydrogen is substituted by a Group 17 element (fluorine, chlorine, bromine, iodine, astatine) , and include a fluoroalkyl group, a chloroalkyl group, a bromoalkyl group, an iodoalkyl group and the like. Specifically, a methyl fluoride group, a methyl chloride group can be mentioned, a fluoroethyl group, a chloroethyl group and the like. However, the halogen element contained ​​​The number or type may be one or plural. Further, in the aryl group having 6 to 13 carbon atoms Examples of the aryl group include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. It can be listed as an example. Further, the aryl group may have a substituent, and the substituents may be bonded to each other to form a ring. Examples of the substituent include an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 13 carbon atoms can also be selected as a substituent. Specifically, as the alkyl group having 1 to 6 carbon atoms, there are a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, te rt-butyl group, an n-hexyl group, etc. Further, specifically, as the cycloalkyl group having 3 to 6 carbon atoms, there are a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, etc. Further, specifically, as the aryl group having 6 to 13 carbon atoms, there are a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. as specific examples that can be listed.

[0150] Also, Ar 1 and R 1 to R 6 represent an aryl group, and at least one of R 1 to R 4 has a cyano group.

[0151] Further, in the iridium complex that can be suitably used for the light-emitting element of one aspect of the present invention the aryl group bonded to the nitrogen in the nitrogen-containing five-membered heterocyclic skeleton is a substituted or unsubstituted phenyl group, which can be vacuum-deposited at a relatively low temperature and has a high triplet excitation energy level, so it can be suitably used for a light-emitting element that exhibits high-energy light emission such as blue light, and is preferred is preferable. The iridium complex is an iridium complex represented by the following general formulas (G5) and (G6).

[0152] [Chemical formula]

[0153] In the above general formula (G5), R 7 and R 11 each represent an alkyl group having 1 to 6 carbon atoms, and R and R 7 and R 11 have the same structure as each other. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, and the like.

[0154] Also, R 8 to R 10 each independently represent any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted phenyl group, or a cyano group. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hex yl group, and the like. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group and the like. At least one of R to R preferably has a cyano group. 8 to R 10

[0155] Also, R 1 to R 4 ​is, independently of each other, hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, and the like. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and the like. Specific examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, and the like. It is advantageous in terms of ease of synthesis and raw material price that all of R to R are hydrogen. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n -hexyl group, and the like. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and the like. Specific examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, and the like. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and the like. Specific examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, and the like. Specific examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, and the like. Specific examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, and the like. In addition, R 1 to R 4 are all hydrogen, which is advantageous in terms of ease of synthesis and raw material price. Advantageous.

[0156] In addition, R 5 represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, and the like. Specific examples of the haloalkyl group having 1 to 6 carbon atoms include an alkyl group in which at least one hydrogen is replaced by a Group 17 element (fluorine, chlorine, bromine, iodine, astatine), such as a fluorinated alkyl group, a chlorinated alkyl group, a brominated alkyl group, an iodinated alkyl group, and the like. Specific examples include a methyl fluoride group, a methyl chloride group, an ethyl fluoride group, an ethyl chloride group, Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, and the like. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, and the like. Specific examples of the haloalkyl group having 1 to 6 carbon atoms include an alkyl group in which at least one hydrogen is replaced by a Group 17 element (fluorine, chlorine, bromine, iodine, astatine), such as a fluorinated alkyl group, a chlorinated alkyl group, a brominated alkyl group, an iodinated alkyl group, and the like. Specific examples of the haloalkyl group having 1 to 6 carbon atoms include an alkyl group in which at least one hydrogen is replaced by a Group 17 element (fluorine, chlorine, bromine, iodine, astatine), such as a fluorinated alkyl group, a chlorinated alkyl group, a brominated alkyl group, an iodinated alkyl group, and the like. Specific examples of the haloalkyl group having 1 to 6 carbon atoms include an alkyl group in which at least one hydrogen is replaced by a Group 17 element (fluorine, chlorine, bromine, iodine, astatine), such as a fluorinated alkyl group, a chlorinated alkyl group, a brominated alkyl group, an iodinated alkyl group, and the like. Specific examples include a methyl fluoride group, a methyl chloride group, an ethyl fluoride group, an ethyl chloride group, The number or type of halogen elements contained therein is as follows: The aryl group having 6 to 13 carbon atoms may be a phenyl group. Specific examples of the aryl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. Furthermore, the aryl group may have substituents, and the substituents may be bonded to each other. The substituent may be an alkyl group having 1 to 6 carbon atoms, a group having 3 or more carbon atoms, or a group having 4 or more carbon atoms. Cycloalkyl groups having up to 6 carbon atoms or aryl groups having 6 to 13 carbon atoms are also selected as substituents. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, Propyl, isopropyl, butyl, isobutyl, tert-butyl, n-hexyl Examples of the cycloalkyl group having 3 to 6 carbon atoms include a cycloalkyl group. Specifically, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc. Examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, Specific examples include a naphthyl group, a biphenyl group, and a fluorenyl group.

[0157] [ka]

[0158] In the above general formula (G6), R 7 and R 11 represents an alkyl group having 1 to 6 carbon atoms; , R 7 and R 11 The alkyl groups having 1 to 6 carbon atoms are specifically Specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, Examples include a tert-butyl group and an n-hexyl group.

[0159] R 8 and even R 10 each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted phenyl group, or a cyano group. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, etc. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, etc. Incidentally, it is preferable that at least one of R to R has a cyano group. In addition, R 8 to R 10 each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl

[0160] group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n 1 to R 4 -hexyl group, etc. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, etc. Specific examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. Incidentally, it is preferable that all of R to R are hydrogen in terms of ease of synthesis and raw material price. In addition, R to R each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl 1 to R 4 are all hydrogen, which is is advantageous.

[0161] Also, R 5 and R 6 each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms The alkyl group having 1 to 6 carbon atoms specifically includes a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n- hexyl group, etc. Further, as the haloalkyl group having 1 to 6 carbon atoms, is an alkyl group in which at least one hydrogen is substituted by a Group 17 element (fluorine, chlorine, bromine, iodine, astatine) and includes a fluoroalkyl group, a chloroalkyl group, a bromoalkyl group, an iodoalkyl group, etc. Specifically, a methyl fluoride group, a methyl chloride group a ethyl fluoride group, a ethyl chloride group, etc. can be mentioned. However, the number or type of halogen elements contained may be one or plural respectively. Further, as the aryl group having 6 to 13 carbon atoms, includes a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. as examples Furthermore, the aryl group may have a substituent, and the substituents may be bonded to each other to form a ring. As the substituent, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 13 carbon atoms can also be selected as a substituent. Specifically, as the alkyl group having 1 to 6 carbon atoms, includes a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, te rt-butyl group, an n-hexyl group, etc. Further, as the cycloalkyl group having 3 to 6 carbon atoms, ​Specific examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and the like. Specific examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, and the like.

[0162] In addition, in the iridium complex that can be suitably used for the light-emitting element of one aspect of the present invention having a 1H-triazole skeleton as a ligand, it can have a high triplet excitation energy level and is therefore particularly preferably used for a light-emitting element that exhibits high-energy light emission such as blue light. The above iridium complex is an iridium complex represented by the following general formulas (G7) and (G8).

[0163] [Chemical formula]

[0164] In the above general formula (G7), Ar 1 represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, and the like. When the aryl group has a substituent, the substituent can be selected from an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, and the like. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms also include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and the like. methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-hexyl group, and the like. In addition, the cycloalkyl group having 3 to 6 carbon atoms​​ Examples of the kill group include, specifically, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and the like. Examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, and the like as specific examples.

[0165] Also, R 1 to R 4 each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n -hexyl group, and the like. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohex yl group, and the like. Specific examples of the aryl group having 6 to 13 carbon atoms include a phen yl group, a naphthyl group, a biphenyl group, a fluorenyl group, and the like. It should be noted that it is advantageous in terms of ease of synthesis and raw material price that all of R to R are hydrogen. 1 to R 4

[0166] Also, R 6 represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isoprop yl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, and the like. ​​​​ It can be formed. In addition, as the haloalkyl group having 1 to 6 carbon atoms, at least one hydrogen is an alkyl group substituted by a Group 17 element (fluorine, chlorine, bromine, iodine, astatine), such as a fluorinated alkyl group, a chlorinated alkyl group, a brominated alkyl group, an iodinated alkyl group and the like. Specifically, a methyl fluoride group, a methyl chloride group, an ethyl fluoride group, an ethyl chloride group and the like can be mentioned. However, the number or type of halogen elements contained may be one or a plurality respectively Also, as the aryl group having 6 to 13 carbon atoms, a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. can be specifically mentioned as examples Furthermore, the aryl group may have a substituent, and the substituents may be bonded to each other to form a ring. As the substituent, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 13 carbon atoms can also be selected as a substituent Specifically, as the alkyl group having 1 to 6 carbon atoms, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group and the like can be mentioned. Also, specifically, as the cycloalkyl group having 3 to 6 carbon atoms, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, etc. can be mentioned. Also, as the aryl group having 6 to 13 carbon atoms, a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. can be specifically mentioned as examples In addition, Ar and the aryl group represented by R to R and at least one of R

[0167] Moreover, Ar 1 、R 1 to R 4 、and R 6 、and the aryl group represented by R 1 to R 4 of at least At least one has a cyano group.

[0168]

Chemical formula

[0169] In the general formula (G8), R 7 and R 11 represent alkyl groups having 1 to 6 carbon atoms , R 7 and R 11 have the same structure as each other. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, and the like.

[0170] Also, R 8 to R 10 each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a carbon cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted phenyl group, or a cyano group any one of which. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hex yl group, and the like. Also, specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group and the like. Note that at least one of R 8 to R 10 has a cyano group which is preferable.

[0171] Also, R 1 to R 4 each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, the number of carbon atoms A cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms is represented by any of them. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n -hexyl group and the like. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohex yl group and the like. Specific examples of the aryl group having 6 to 13 carbon atoms include a phen yl group, a naphthyl group, a biphenyl group, a fluorenyl group and the like. It should be noted that R to R 1 to R 4 are all hydrogen, which is advantageous in terms of ease of synthesis and raw material price .

[0172] In addition, R 6 represents any of hydrogen, an alkyl group having 1 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms , or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isoprop yl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group and the like. Examples of the haloalkyl group having 1 to 6 carbon atoms include an alkyl group in which at least one hydrogen is substituted by a Group 17 element (fluorine, chlorine, bromine, iodine, astatine), and include a fluoroalkyl group, a chloroalkyl group, a bromoalkyl group, an iodoalkyl group and the like. Specific examples include a methyl fluoride group, a methyl chloride group, an ethyl fluoride group, an ethyl chloride group and the like. However, the number or type of halogen elements contained are each ​It may be one or plural. Further, examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. can be mentioned. Further, the aryl group may have a substituent, and the substituents may be bonded to each other to form a ring. Examples of the substituent include an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 13 carbon atoms can also be selected as the substituent. Specifically, examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, etc. Further, specifically, examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, etc. Further, examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. can be mentioned. For the alkyl group and aryl group represented by R in the general formulas (G2) to (G8), for example, the groups represented by the following structural formulas (R-1) to (R-29) can be applied. Note that the groups that can be used as the alkyl group and aryl group are not limited to these. In the general formulas (G1) to (G4) and (G7), Ar represented as and the aryl group as mentioned above, specifically, examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, etc. Further, specifically, examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, etc. Further, examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. can be mentioned. For the alkyl group and aryl group represented by R in the general formulas (G2) to (G8), for example, the groups represented by the following structural formulas (R-1) to (R-29) can be applied. Note that the groups that can be used as the alkyl group and aryl group are not limited to these.

[0173] For R in the above general formulas (G2) to (G8) 1 to R 4 The alkyl group and aryl group represented by For example, the groups represented by the following structural formulas (R-1) to (R-29) can be applied. The groups that can be used as the alkyl group and aryl group are not limited to these. In the general formulas (G1) to (G4) and (G7), Ar represented as

[0174]

Chemical formula

[0175] Further, in the general formulas (G1) to (G4) and (G7), Ar 1 represented as The reel group, and in general formula (G1), Ar 2 Examples of the aryl group represented by include the groups represented by the above structural formulas (R-12) to (R-29). Note that Ar 1 and Ar 2 The groups that can be used as are not limited to these.

[0176] Also, in general formulas (G5), (G6), and (G8), R 7 and R 11 The alkyl group represented by, for example, the groups represented by the above structural formulas (R-1) to (R-10) can be applied. Note that the groups that can be used as the alkyl group are not limited to these.

[0177] Also, in general formulas (G5), (G6), and (G8), R 8 to R 10 The alkyl group or substituted or unsubstituted phenyl group represented by, for example, the groups represented by the above structural formulas (R-1) to (R-2 2) can be applied. Note that the groups that can be used as the alkyl group or phenyl group are not limited to these.

[0178] Also, in the above general formulas (G3) to (G6), R 5 , and in general formulas (G4), (G6) to ( G8), R 6 The alkyl group, aryl group, or haloalkyl group represented by, for example, the above described structural formulas (R-1) to (R-29), and the following structural formulas (R-30) to (R-37) represented groups can be applied. Note that the groups that can be used as the alkyl group, aryl group, or haloalkyl group are not limited to these.

[0179]

Chemical formula

[0180] ≪Specific Examples of Iridium Complexes≫ As specific structures of the iridium complexes represented by the above general formulas (G1) to (G8), compounds represented by the following structural formulas (100) to (134) and the like can be mentioned. Note that, the iridium complexes represented by the general formulas (G1) to (G8) are not limited to the following examples.

[0181]

Chem.

[0182]

Chem.

[0183]

Chem.

[0184]

Chem.

[0185]

Chem.

[0186]

Chem.

[0187] As described above, since the iridium complexes exemplified above have relatively low HOMO levels and LU MO levels, they are suitable as guest materials for the light-emitting elements of one aspect of the present invention. Thereby, a light-emitting element with good luminous efficiency can be manufactured. Also, the above-exemplified Since iridium complexes have high triplet excitation energy levels, they are particularly suitable as guest materials for blue light-emitting elements. Thus, a blue light-emitting element with good luminous efficiency can be fabricated. Further, since the iridium complexes exemplified above have good resistance to repeated oxidation and reduction, a light-emitting element with good driving life can be fabricated by using the iridium complexes in a light-emitting element. Also, as the light-emitting material contained in the light-emitting layer 130, any material capable of converting triplet excitation energy into light may be used. Examples of materials capable of converting triplet excitation energy into light include, in addition to phosphorescent materials, thermally activated delayed fluorescence (TADF) materials. Therefore, the portion described as a phosphorescent material may be read as a thermally activated delayed fluorescence material. A thermally activated delayed fluorescence material is a material having a small difference between the triplet excitation energy level and the singlet excitation energy level and having a function of converting energy from the triplet excited state to the singlet excited state by reverse intersystem crossing. Therefore, up-conversion (reverse intersystem crossing) from the triplet excited state to the singlet excited state is possible with a small amount of thermal energy, and efficient light emission (fluorescence) from the singlet excited state can be exhibited. Further, conditions for efficiently obtaining thermally activated delayed fluorescence include that the energy difference between the triplet excitation energy level and the singlet excitation energy level is preferably greater than 0 eV and 0.2 eV or less, more preferably greater than 0 eV and 0.1 eV or less. When the thermally activated delayed fluorescence material is composed of one type of material, for example, the following materials can be used

[0188]

[0189] ​ can be used.

[0190] First, fullerenes and their derivatives, acridine derivatives such as proflavine, eosin, etc. can be mentioned. In addition, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd), etc. can be mentioned. Examples of the metal-containing porphyrin include protoporphyrin-tin fluoride complex (SnF2(Proto IX)), mesoporphyrin-tin fluoride complex (SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (SnF2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (SnF2(Copro III-4Me)), octaethylporphyrin-tin fluoride complex (SnF2(OEP)), etioporphyrin-tin fluoride complex (SnF2(Etio I)), octaethylporphyrin-platinum chloride complex (PtCl2OEP), etc. can be mentioned.

[0191] In addition, as the thermally activated delayed fluorescence material composed of one kind of material, a heterocyclic compound having a π-electron excess type heteroaromatic ring and a π-electron deficient type heteroaromatic ring can also be used. Specifically, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCzPTzn), 2-[4-(10H-phenoxazine-10-yl)phenyl]-4, ​​​​​​​​​​6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5- phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl -1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl- 9H-acridin-10-yl)-9H-xanthene-9-one (abbreviation: ACRXTN) , bis[4-(9,9-dimethyl-9,10-dihydroacridin)phenyl]sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10’H-spiro[acridine -9,9’-anthracene]-10’-one (abbreviation: ACRSA), etc. are mentioned. The complex ring compound has a π-electron-excessive heteroaromatic ring and a π-electron-deficient heteroaromatic ring, so it has high electron transport property and hole transport property, which is preferable. Among them, among the skeletons having a π-electron-deficient heteroaromatic ring , a diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), or a tri azine skeleton is preferable because it is stable and has good reliability. Also, among the skeletons having a π-electron-excessive heteroaromatic ring , an acridine skeleton, a phenoxazine skeleton, a thiophene skeleton, a furan skeleton , and a pyrrole skeleton are stable and have good reliability, so it is preferable to have any one or more selected from among these skeletons . As the pyrrole skeleton, an indole skeleton, a carbazole skeleton, and a 3-(9-phenyl-9H-carbazol-3-yl)- 9H-carbazole skeleton are particularly preferable. Note that a substance in which a π-electron-excessive heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded has both strong donor property of the π-electron-excessive heteroaromatic ring and acceptor property of the π-electron-deficient heteroaromatic ring, and the difference between the singlet excitation energy level and the triplet excitation energy level is small, so it is particularly preferable.

[0192] Note that the light-emitting layer 130 can also be composed of two or more layers. For example, when the first light-emitting layer and the second light-emitting layer are laminated in order from the hole transport layer side to form the light-emitting layer 130, a substance having hole transport properties is used as the host material of the first light-emitting layer, and a substance having electron transport properties is used as the host material of the second light-emitting layer and the like. Further, the light-emitting materials of the first light-emitting layer and the second light-emitting layer may be the same material or different materials, and may be materials having a function of emitting light of the same color or materials having a function of emitting light of different colors . By using light-emitting materials having functions of emitting lights of different colors in the two light-emitting layers, respectively, a plurality of emissions can be obtained simultaneously. In particular, it is preferable to select the light-emitting materials used for each light-emitting layer so that the emissions exhibited by the two light-emitting layers become white.

[0193] In addition, in the light-emitting layer 130, it may have materials other than the host material 131 and the guest material 132.

[0194] Note that the light-emitting layer 130 can be formed by methods such as a vapor deposition method (including a vacuum vapor deposition method), an inkjet method, a coating method, and gravure printing. Further, in addition to the materials described above, it may have inorganic compounds such as quantum dots or polymer compounds (oligomers, dendrimers, polymers, etc.).

[0195] <<Hole injection layer>> The hole injection layer 111 has a function of promoting hole injection by reducing the hole injection barrier from one of the pair of electrodes (electrode 101 or electrode 102). For example, it is formed of a transition metal oxide, a phthalocyanine derivative, or an aromatic amine. The transition metal oxide and Examples include molybdenum oxides, vanadium oxides, ruthenium oxides, tungsten oxides , manganese oxides, etc. Examples of phthalocyanine derivatives include phthalocyanine and metal phthalocyanines, etc. Examples of aromatic amines include benzidine derivatives and phen ylenediamine derivatives, etc. Polymer compounds such as polythiophene and polyaniline can also be used. For example, poly(ethylenedioxythiophene) / poly(styrenesulfonic acid), which is a self-doped polythiophene, is a representative example.

[0196] As the hole injection layer 111, a layer having a composite material of a hole transporting material and a material showing electron accepting property with respect to this can also be used. Alternatively, a laminate of a layer containing a material showing electron accepting property and a layer containing a hole transporting material may be used. Charge transfer is possible between these materials in a steady state or in the presence of an electric field. Examples of materials showing electron accepting property include organic acceptors such as quinodimethane derivatives, chloranil derivatives, and hexaazatriphenylene derivatives. Specifically, compounds having an electron withdrawing group (halogen group or cyano group), such as 7,7,8,8-tetracyano-2,3,5,6-tetrafluorobenzoquinodimethane (abbreviation: F4-TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), etc. are mentioned. Also, transition metal oxides, for example, oxides of metals from Group 4 to Group 8 can be used. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, rhenium oxide, etc. Among them, molybdenum oxide is in the air Among them, it is preferable because it is stable, has low hygroscopicity, and is easy to handle.

[0197] As the hole transporting material, a material with higher hole transporting property than electrons can be used, and it is preferably a material having a hole mobility of 1 ×10 -6 cm 2 / Vs or more. Specifically, aromatic amines, carbazole derivatives, aromatic hydrocarbons, stilbene derivatives, etc., which were mentioned as hole transporting materials that can be used in the light emitting layer 130, can be used. Also, the hole transporting material may be a polymer compound.

[0198] ≪Hole Transport Layer≫ The hole transport layer 112 is a layer containing a hole transporting material, and the hole transporting materials exemplified as the material of the hole injection layer 111 can be used. Since the hole transport layer 112 has a function of transporting the holes injected into the hole injection layer 111 to the light emitting layer 130, it preferably has the same or nearly the same HOMO level as the HOMO level of the hole injection layer 111.

[0199] Also, it is preferably a substance having a hole mobility of 1×10 -6 cm 2 / Vs or more. However, as long as it is a substance with higher hole transporting property than electrons, substances other than these may be used. Note that the layer containing a substance with high hole transporting property may be not only a single layer, but also two or more layers of the layers composed of the above substances laminated.

[0200] ≪Electron Transport Layer≫ The electron transport layer 118 has a function of transporting the electrons injected from the other of the pair of electrodes (electrode 101 or electrode 102) through the electron injection layer 119 to the light emitting layer 130. As the electron transporting material, a material with higher electron transporting property than holes can be used, and 1×10 ​-6 cm 2 It is preferably a material having an electron mobility of / Vs or more. A compound that easily accepts electrons (a material having electron transporting properties) such as a nitrogen-containing heteroaromatic compound can be used as a π-electron deficient heteroaromatic or a metal complex. Specifically, the quinoline ligand, benzoquinoline ligand, oxazole ligand, or metal complex having a thiazole ligand, oxadiazole derivative, triazole derivative, benzimidazole derivative, quinoxaline derivative, dibenzoquinoxaline derivative, phenanthroline derivative, pyridine derivative, bipyridine derivative, pyrimidine derivative, triazine derivative, etc. mentioned as the electron transporting material that can be used for the light emitting layer 130 can be used. Further, it is preferably a substance having an electron mobility of 1×10 cm / Vs or more. Note that, as long as it is a substance having higher electron transporting properties than holes, substances other than those described above may be used as the electron transport layer. Further, the electron transport layer 118 may be not only a single layer, but also two or more layers of the layers made of the above substances laminated. As a compound that easily accepts electrons (a material having electron transporting properties), a π-electron deficient heteroaromatic such as a nitrogen-containing heteroaromatic compound or a metal complex can be used. Specifically, the quinoline ligand, benzoquinoline ligand, oxazole ligand, or metal complex having a thiazole ligand, oxadiazole derivative, triazole derivative, benzimidazole derivative, quinoxaline derivative, dibenzoquinoxaline derivative, phenanthroline derivative, pyridine derivative, bipyridine derivative, pyrimidine derivative, triazine derivative, etc. mentioned as the electron transporting material that can be used for the light emitting layer 130 can be used. As a compound that easily accepts electrons (a material having electron transporting properties), a π-electron deficient heteroaromatic such as a nitrogen-containing heteroaromatic compound or a metal complex can be used. Specifically, the quinoline ligand, benzoquinoline ligand, oxazole ligand, or metal complex having a thiazole ligand, oxadiazole derivative, triazole derivative, benzimidazole derivative, quinoxaline derivative, dibenzoquinoxaline derivative, phenanthroline derivative, pyridine derivative, bipyridine derivative, pyrimidine derivative, triazine derivative, etc. mentioned as the electron transporting material that can be used for the light emitting layer 130 can be used. Specifically, the quinoline ligand, benzoquinoline ligand, oxazole ligand, or metal complex having a thiazole ligand, oxadiazole derivative, triazole derivative, benzimidazole derivative, quinoxaline derivative, dibenzoquinoxaline derivative, phenanthroline derivative, pyridine derivative, bipyridine derivative, pyrimidine derivative, triazine derivative, etc. mentioned as the electron transporting material that can be used for the light emitting layer 130 can be used. Specifically, the quinoline ligand, benzoquinoline ligand, oxazole ligand, or metal complex having a thiazole ligand, oxadiazole derivative, triazole derivative, benzimidazole derivative, quinoxaline derivative, dibenzoquinoxaline derivative, phenanthroline derivative, pyridine derivative, bipyridine derivative, pyrimidine derivative, triazine derivative, etc. mentioned as the electron transporting material that can be used for the light emitting layer 130 can be used. Specifically, the quinoline ligand, benzoquinoline ligand, oxazole ligand, or metal complex having a thiazole ligand, oxadiazole derivative, triazole derivative, benzimidazole derivative, quinoxaline derivative, dibenzoquinoxaline derivative, phenanthroline derivative, pyridine derivative, bipyridine derivative, pyrimidine derivative, triazine derivative, etc. mentioned as the electron transporting material that can be used for the light emitting layer 130 can be used. -6 cm 2 / Vs or more It is preferably a substance having an electron mobility of 1×10 cm / Vs or more. Note that, as long as it is a substance having higher electron transporting properties than holes, substances other than those described above may be used as the electron transport layer. As long as it is a substance having higher electron transporting properties than holes, substances other than those described above may be used as the electron transport layer. Further, the electron transport layer 118 may be not only a single layer, but also two or more layers of the layers made of the above substances laminated.

[0201] Further, a layer for controlling the movement of electron carriers may be provided between the electron transport layer 118 and the light emitting layer 130. The layer for controlling the movement of electron carriers is a layer in which a small amount of a substance having high electron trapping properties is added to a material having high electron transporting properties as described above, and by suppressing the movement of electron carriers, it becomes possible to adjust the carrier balance. Such a configuration exhibits a great effect in suppressing problems (for example, a decrease in the device lifetime) caused by electrons passing through the light emitting layer. The layer for controlling the movement of electron carriers is a layer in which a small amount of a substance having high electron trapping properties is added to a material having high electron transporting properties as described above, and by suppressing the movement of electron carriers, it becomes possible to adjust the carrier balance. Such a configuration exhibits a great effect in suppressing problems (for example, a decrease in the device lifetime) caused by electrons passing through the light emitting layer. Such a configuration exhibits a great effect in suppressing problems (for example, a decrease in the device lifetime) caused by electrons passing through the light emitting layer. Such a configuration exhibits a great effect in suppressing problems (for example, a decrease in the device lifetime) caused by electrons passing through the light emitting layer.

[0202] <<Electron injection layer>> The electron injection layer 119 has a function of promoting electron injection by reducing the electron injection barrier from the electrode 102, and for example, Group 1 metals, Group 2 metals, or their oxides, halides , carbonates, etc. can be used. Also, a composite material of the electron transporting material shown above and a material exhibiting electron donating properties can be used. Examples of materials exhibiting electron donating properties include Group 1 metals, Group 2 metals, or their oxides. Specifically, lithium fluoride (LiF), sodium fluoride (NaF), cesium fluoride (CsF ), calcium fluoride (CaF2), lithium oxide (LiO ), etc., such as alkali metals, alkaline earth metals, or their compounds can be used. Also, rare earth metal compounds such as erbium fluoride (ErF3) can be used. Further, an electride may be used for the electron injection layer 119. Examples of the electride include substances obtained by adding electrons at a high concentration to a mixed oxide of calcium and aluminum. Also, a substance that can be used in the electron transport layer 118 may be used for the electron injection layer x 119. In addition, a composite material formed by mixing an organic compound and an electron donor may be used for the electron injection layer 119. Such a composite material has excellent electron injection properties and electron transport properties because electrons are generated in the organic compound by the electron donor. In this case, the organic compound is preferably a material excellent in transporting the generated electrons. Specifically, for example, the substances constituting the electron transport layer 118 described above (metal complexes, heteroaromatic compounds, etc.) can be used. The electron donor may be any substance that exhibits electron donating properties with respect to the organic compound. Specifically,

[0203] Alkali metals, alkaline earth metals, and rare earth metals are preferred, such as lithium, sodium , cesium, magnesium, calcium, erbium, ytterbium, etc. In addition, alkali metal oxides and alkaline earth metal oxides are preferred, such as lithium oxide, cal cium oxide, barium oxide, etc. In addition, Lewis bases such as magnesium oxide can also be used. In addition, organic compounds such as tetrathiafulvalene (abbreviation: TTF) can also be used.

[0204] Note that the above-mentioned light-emitting layer, hole injection layer, hole transport layer, electron transport layer, and electron injection layer can be formed by evaporation method (including vacuum evaporation method), inkjet method, coating method, gravure printing, etc. In addition to the above-mentioned materials, inorganic compounds such as quantum dots and high molecular compounds (oligomers, dendrimers, polymers, etc.) can also be used in the above-mentioned light-emitting layer, hole injection layer, hole transport layer, electron transport layer, and electron injection layer.

[0205] Note that as the quantum dots, colloidal quantum dots, alloy-type quantum dots, core-shell type quantum dots, core-type quantum dots, etc. can also be used. In addition, quantum dots containing element groups of Group 2 and Group 16, Group 13 and Group 15, Group 13 and Group 17, Group 11 and Group 17, or Group 14 and Group 15 can also be used. Alternatively, quantum dots containing elements such as cadmium (Cd), selenium (Se), zinc (Zn ), sulfur (S), phosphorus (P), indium (In), tellurium (Te), lead (Pb), gallium (Ga ), arsenic (As), aluminum (Al), etc. can also be used.

[0206] ≪Pair of electrodes≫ Electrodes 101 and 102 have the function of an anode or a cathode of a light-emitting element. The electrodes 101 and 102 can be formed using metals, alloys, conductive compounds, and mixtures or laminates thereof .

[0207] It is preferable that one of electrode 101 or electrode 102 is formed of a conductive material having a function of reflecting light. Examples of the conductive material include aluminum (Al) or an alloy containing Al . Examples of the alloy containing Al include an alloy containing Al and L (L represents one or more of titanium (Ti), neodymium (Nd), nickel (Ni), and lanthanum (La)), such as an alloy containing Al and Ti, or an alloy containing Al and Ni and La . Aluminum has a low resistance value and a high light reflectance. Also, since aluminum is abundant in the earth's crust and is inexpensive, the manufacturing cost of a light-emitting element using aluminum can be reduced . Further, an alloy containing silver (Ag) or Ag and N (N represents one or more of yttrium (Y), Nd, magnesium (Mg), ytterbium (Yb), Al, Ti, gallium (Ga), zinc (Zn), indium (In), tungsten (W), manganese (Mn), tin (Sn), iron (Fe), Ni, copper (Cu), palladium (Pd), iridium (Ir ), or gold (Au)) may be used. Examples of the alloy containing silver include an alloy containing silver, palladium, and copper, an alloy containing silver and copper, an alloy containing silver and magnesium, an alloy containing silver and nickel, an alloy containing silver and gold, an alloy containing silver and ytterbium . In addition, transition metals such as tungsten, chromium (Cr), molybdenum (Mo ), copper, and titanium can be used . . . . . . . Other examples include alloys containing silver and ytterbium. In addition, transition metals such as tungsten, chromium (Cr), molybdenum (Mo ), copper, and titanium can be used

[0208] Also, the light emitted from the light-emitting layer is extracted through one or both of the electrodes 101 and 102. Therefore, at least one of the electrodes 101 and 102 is preferably formed of a conductive material having a function of transmitting light. As the conductive material, the transmittance of visible light is 40% or more and 100% or less, preferably 60% or more and 100% or less, and its resistivity is 1 × 10 Ω·cm or less. Ω·cm or less. -2 Examples of such conductive materials include those having a resistivity of 1 × 10

[0209] Also, the electrodes 101 and 102 may be formed of a conductive material having a function of transmitting light and a function of reflecting light. As the conductive material, the reflectance of visible light is 20 % or more and 80% or less, preferably 40% or more and 70% or less, and its resistivity is 1 × 10 Ω·cm or less. -2 Examples of such conductive materials include those having a resistivity of 1 × 10 Ω·cm or less. For example, they can be formed using one or more of a conductive metal, alloy, conductive compound, etc. Specifically, for example, indium tin oxide (Indium Tin Oxide, hereinafter referred to as ITO), silicon or indium tin oxide containing silicon oxide (abbreviation: ITSO), indium oxide - zinc oxide (Indium Zinc Oxide), indium tin oxide containing titanium, indium titanium oxide, indium oxide containing tungsten oxide and zinc oxide, and other metal oxides can be used. Also, a metal thin film having a thickness that allows light to pass through (preferably 1 nm or more and 30 nm or less) can be used. As the metal, for example, Ag, or an alloy such as Ag and Al, Ag and Mg, Ag and Au, Ag and Yb, etc. can be used. or less) can be used. As the metal, for example, Ag, or an alloy such as Ag and Al, Ag and Mg, Ag and Au, Ag and Yb, etc. can be used. can be used.

[0210] In addition, in this specification and the like, a material having a function of transmitting light may be a material having a function of transmitting visible light and having conductivity. For example, in addition to the oxide conductor typified by ITO as described above , it includes an oxide semiconductor or an organic conductor containing an organic substance. Examples of the organic conductor containing an organic substance include a composite material formed by mixing an organic compound and an electron donor (donor), a composite material formed by mixing an organic compound and an electron acceptor (acceptor), and the like. In addition, an inorganic carbon-based material such as graphene may be used. Also, the resistance rate of the material is preferably 1×10 5 Ω·cm or less, more preferably 1×10 4 Ω·cm or less.

[0211] Further, one or both of the electrode 101 and the electrode 102 may be formed by laminating a plurality of the above materials.

[0212] In addition, in order to improve the light extraction efficiency, a material having a higher refractive index than the electrode may be formed in contact with the electrode having a function of transmitting light. Such a material may be any material having a function of transmitting visible light, whether it has conductivity or not. For example, in addition to the oxide conductor as described above, an oxide semiconductor and an organic substance are included. Examples of the organic substance include materials exemplified for the light-emitting layer, hole injection layer, hole transport layer, electron transport layer, or electron injection layer. In addition, an inorganic carbon-based material or a metal in the form of a thin film through which light can pass can also be used. A plurality of layers of several nm to several tens of nm may be laminated using these materials having a high refractive index.

[0213] ​​​​When the electrode 101 or the electrode 102 functions as a cathode, it preferably has a material with a small work function (3.8 eV or less). For example, elements belonging to Group 1 or Group 2 of the periodic table (alkali metals such as lithium, sodium, cesium, etc., alkaline earth metals such as calcium, strontium, etc., magnesium, etc.), alloys containing these elements (e.g., Ag and Mg, Al and Li), rare earth metals such as europium (Eu), Yb, etc., alloys containing these rare earth metals, aluminum, alloys containing silver, etc. can be used.

[0214] Also, when the electrode 101 or the electrode 102 is used as an anode, it is preferable to use a material with a large work function (4. 0 eV or more).

[0215] In addition, the electrodes 101 and 102 may be a laminate of a conductive material having a function of reflecting light and a conductive material having a function of transmitting light. In that case, the electrodes 101 and 1 02 are preferable because they can have a function of adjusting the optical distance so as to resonate the desired light from each light-emitting layer and enhance the light of that wavelength.

[0216] The film formation methods of the electrodes 101 and 102 can be appropriately used, such as sputtering method, evaporation method, printing method, coating method , MBE (Molecular Beam Epitaxy) method, CVD method, pulse laser deposition method, ALD (Atomic Layer Deposition) method, etc.

[0217] ≪Substrate≫ Also, the light-emitting element according to one aspect of the present invention may be fabricated on a substrate made of glass, plastic, etc. As the order of fabrication on the substrate, they may be laminated in order from the electrode 101 side, or the They may be laminated in order from the pole 102 side.

[0218] Note that as the substrate on which the light-emitting element according to one embodiment of the present invention can be formed, for example, glass, quartz , or plastic can be used. A flexible substrate may also be used. A flexible substrate is a substrate that can be bent (flexible), and examples thereof include plastic substrates made of, for example, polycarbonate , polyarylate, etc. Also, films, inorganic vapor deposition films, etc. can also be used. Note that as long as it functions as a support in the manufacturing process of the light-emitting element and the optical element, other materials may be used. Alternatively, as long as it has a function of protecting the light-emitting element and the optical element.

[0219] For example, in the present invention and the like, a light-emitting element can be formed using various substrates. The type of the substrate is not particularly limited. As an example of the substrate, 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 a stainless steel foil, a tungsten substrate, a substrate having a tungsten foil, a flexible substrate, a laminated film, a cellulose nanofiber (CNF) containing a fibrous material and paper, or a base film, etc. Examples of the glass substrate include barium borosilicate glass, aluminoborosilicate glass, or soda lime glass, etc. Examples of the flexible substrate, the laminated film, the base film, etc. include the following. For example, polyethylene terephthalate (PET), p olyethylene naphthalate (PEN), polyethersulfone (PES), polytetrafluoro There are plastics typified by polytetrafluoroethylene (PTFE). Or, as an example, there are resins such as acrylic, etc. Or, as an example, there are polypropylene, polyester, vinylidene fluoride, or polyvinyl chloride, etc. Or, as an example, there are polyamide, polyimide, aramid, epoxy, inorganic vapor deposition film, or papers, etc.

[0220] Also, a flexible substrate may be used as the substrate, and a light-emitting element may be formed directly on the flexible substrate. Or, a release layer may be provided between the substrate and the light-emitting element. The release layer is used to separate from the substrate after partially or completely completing the light-emitting element thereon and transfer it to another substrate. At that time, the light-emitting element can be transferred to a substrate with poor heat resistance or a flexible substrate. In addition, for the above-mentioned release layer, for example, a laminated structure of inorganic films of a tungsten film and a silicon oxide film, or a structure in which a resin film such as polyimide is formed on the substrate can be used.

[0221] That is, a light-emitting element may be formed using a certain substrate, and then the light-emitting element may be transferred to another substrate and arranged on another substrate. As an example of the substrate to which the light-emitting element is transferred, in addition to the above-mentioned substrates, there are cellophane substrates, stone substrates, wood substrates, cloth substrates (including natural fibers (silk, cotton, hemp), synthetic fibers (nylon, polyurethane, polyester) or recycled fibers (acetate, cupra, rayon, recycled polyester), etc.), leather substrates, or rubber substrates. By using these substrates, a light-emitting element that is difficult to break, a light-emitting element with high heat resistance, a light-emitting element with reduced weight, or a light-emitting element with reduced thickness can be obtained.

[0222] Further, for example, a field effect transistor (FET) is formed on the above-described substrate, and a light-emitting element 150 may be fabricated on an electrode electrically connected to the FET. Thereby, an active matrix type display device that controls the driving of the light-emitting element 150 by the FET can be fabricated. Note that in this embodiment, one aspect of the present invention is described, and in other embodiments, another aspect of the present invention is described. However, one aspect of the present invention is not limited to these. That is, in this embodiment and other embodiments, various aspects of the invention are described, so one aspect of the present invention is not limited to a specific aspect. For example, as one aspect of the present invention, an example in the case of applying to a light-emitting element is shown, but one aspect of the present invention is not limited thereto. For example, depending on the case or the situation, one aspect of the present invention may not be applied to the light-emitting element. Or, for example, in one aspect of the present invention, a first organic compound, a second organic compound, and a guest material having a function capable of converting triplet excitation energy into light emission are included, and the LUMO level of the first organic compound is lower than the LUMO level of the second organic compound, and the HOMO level of the first organic compound is lower than the HOMO level of the second organic compound. An example of the case is shown, but one aspect of the present invention is not limited thereto.

[0223] Note that in this embodiment, one aspect of the present invention is described, and in other embodiments, another aspect of the present invention is described. However, one aspect of the present invention is not limited to these. That is, in this embodiment and other embodiments, various aspects of the invention are described, so one aspect of the present invention is not limited to a specific aspect. For example, as one aspect of the present invention, an example in the case of applying to a light-emitting element is shown, but one aspect of the present invention is not limited thereto. For example, depending on the case or the situation, one aspect of the present invention may not be applied to the light-emitting element. Or, for example, in one aspect of the present invention, a first organic compound, a second organic compound, and a guest material having a function capable of converting triplet excitation energy into light emission are included, and the LUMO level of the first organic compound is lower than the LUMO level of the second organic compound, and the HOMO level of the first organic compound is lower than the HOMO level of the second organic compound. An example of the case is shown, but one aspect of the present invention is not limited thereto. For example, depending on the case or the situation, the LUMO level of the first organic compound may not be lower than the LUMO level of the second organic compound in one aspect of the present invention. Or, the HOMO level of the first organic compound may not be lower than the HOMO level of the second organic compound. Or, for example, in one aspect of the present invention, the first organic compound and the second organic compound form an exciplex. Note that in this embodiment, one aspect of the present invention is described, and in other embodiments, another aspect of the present invention is described. However, one aspect of the present invention is not limited to these. That is, in this embodiment and other embodiments, various aspects of the invention are described, so one aspect of the present invention is not limited to a specific aspect. For example, as one aspect of the present invention, an example in the case of applying to a light-emitting element is shown, but one aspect of the present invention is not limited thereto. For example, depending on the case or the situation, one aspect of the present invention may not be applied to the light-emitting element. Or, for example, in one aspect of the present invention, a first organic compound, a second organic compound, and a guest material having a function capable of converting triplet excitation energy into light emission are included, and the LUMO level of the first organic compound is lower than the LUMO level of the second organic compound, and the HOMO level of the first organic compound is lower than the HOMO level of the second organic compound. An example of the case is shown, but one aspect of the present invention is not limited thereto. For example, depending on the case or the situation, the LUMO level of the first organic compound may not be lower than the LUMO level of the second organic compound in one aspect of the present invention. Or, the HOMO level of the first organic compound may not be lower than the HOMO level of the second organic compound. Or, for example, in one aspect of the present invention, the first organic compound and the second organic compound form an exciplex. Note that in this embodiment, one aspect of the present invention is described, and in other embodiments, another aspect of the present invention is described. However, one aspect of the present invention is not limited to these. That is, in this embodiment and other embodiments, various aspects of the invention are described, so one aspect of the present invention is not limited to a specific aspect. For example, as one aspect of the present invention, an example in the case of applying to a light-emitting element is shown, but one aspect of the present invention is not limited thereto. For example, depending on the case or the situation, one aspect of the present invention may not be applied to the light-emitting element. Or, for example, in one aspect of the present invention, a first organic compound, a second organic compound, and a guest material having a function capable of converting triplet excitation energy into light emission are included, and the LUMO level of the first organic compound is lower than the LUMO level of the second organic compound, and the HOMO level of the first organic compound is lower than the HOMO level of the second organic compound. An example of the case is shown, but one aspect of the present invention is not limited thereto. For example, depending on the case or the situation, the LUMO level of the first organic compound may not be lower than the LUMO level of the second organic compound in one aspect of the present invention. Or, the HOMO level of the first organic compound may not be lower than the HOMO level of the second organic compound. Or, for example, in one aspect of the present invention, the first organic compound and the second organic compound form an exciplex. Note that in this embodiment, one aspect of the present invention is described, and in other embodiments, another aspect of the present invention is described. However, one aspect of the present invention is not limited to these. That is, in this embodiment and other embodiments, various aspects of the invention are described, so one aspect of the present invention is not limited to a specific aspect. For example, as one aspect of the present invention, an example in the case of applying to a light-emitting element is shown, but one aspect of the present invention is not limited thereto. For example, depending on the case or the situation, one aspect of the present invention may not be applied to the light-emitting element. Or, for example, in one aspect of the present invention, a first organic compound, a second organic compound, and a guest material having a function capable of converting triplet excitation energy into light emission are included, and the LUMO level of the first organic compound is lower than the LUMO level of the second organic compound, and the HOMO level of the first organic compound is lower than the HOMO level of the second organic compound. An example of the case is shown, but one aspect of the present invention is not limited thereto. For example, depending on the case or the situation, the LUMO level of the first organic compound may not be lower than the LUMO level of the second organic compound in one aspect of the present invention. Or, the HOMO level of the first organic compound may not be lower than the HOMO level of the second organic compound. Or, for example, in one aspect of the present invention, the first organic compound and the second organic compound form an exciplex. Note that in this embodiment, one aspect of the present invention is described, and in other embodiments, another aspect of the present invention is described. However, one aspect of the present invention is not limited to these. That is, in this embodiment and other embodiments, various aspects of the invention are described, so one aspect of the present invention is not limited to a specific aspect. For example, as one aspect of the present invention, an example in the case of applying to a light-emitting element is shown, but one aspect of the present invention is not limited thereto. For example, depending on the case or the situation, one aspect of the present invention may not be applied to the light-emitting element. Or, for example, in one aspect of the present invention, a first organic compound, a second organic compound, and a guest material having a function capable of converting triplet excitation energy into light emission are included, and the LUMO level of the first organic compound is lower than the LUMO level of the second organic compound, and the HOMO level of the first organic compound is lower than the HOMO level of the second organic compound. An example of the case is shown, but one aspect of the present invention is not limited thereto. For example, depending on the case or the situation, the LUMO level of the first organic compound may not be lower than the LUMO level of the second organic compound in one aspect of the present invention. Or, the HOMO level of the first organic compound may not be lower than the HOMO level of the second organic compound. Or, for example, in one aspect of the present invention, the first organic compound and the second organic compound form an exciplex. Examples of cases have been shown, but one aspect of the present invention is not limited thereto. In some cases, or , depending on the situation, in one aspect of the present invention, for example, between a first organic compound and a second organic compound may not form an exciplex. Or, for example, in one aspect of the present invention, the LUMO level of the guest material is higher than the LUMO level of the first organic compound, and an example where the HOMO level of the guest material is higher than the HOMO level of the second organic compound has been shown, but one aspect of the present invention is not limited thereto. In some cases, or depending on the situation, in one aspect of the present invention, for example, the LUMO level of the guest material may not be higher than the LUMO level of the first organic compound. Alternatively, the HOMO level of the guest material may not be higher than the HOMO level of the second organic compound.

[0224] As described above, the configurations shown in the present embodiment can be used in appropriate combination with other embodiments.

[0225] (Embodiment 2) In the present embodiment, a light-emitting element having a configuration different from that of the light-emitting element shown in Embodiment 1 will be described below with reference to FIGS. 3 and 4. In FIGS. 3 and 4, portions having the same functions as the reference numerals shown in FIG. 1 (A) are hatched in the same manner, and the reference numerals may be omitted. Further, portions having the same functions may be denoted by the same reference numerals, and detailed descriptions thereof may be omitted.

[0226] <Example configuration 1 of the light-emitting element> FIG. 3(A) is a cross-sectional schematic view of the light-emitting element 250.

[0227] The light-emitting element 250 shown in FIG. 3(A) is provided between a pair of electrodes (electrode 101 and electrode 102). , having a plurality of light-emitting units (in Fig. 3(A), light-emitting unit 106 and light-emitting unit 1 08). It is preferable that any one of the plurality of light-emitting units has the same configuration as the EL layer 100 shown in Fig. 1. That is, the light-emitting element 150 shown in Fig. 1 has one light-emitting unit, and it is preferable that the light-emitting element 250 has a plurality of light-emitting units . In the light-emitting element 250, although the electrode 101 functions as an anode and the electrode 102 functions as a cathode as described below, the configuration of the light-emitting element 250 may be reversed .

[0228] Also, in the light-emitting element 250 shown in Fig. 3(A), the light-emitting unit 106 and the light-emitting unit 108 are laminated, and a charge generation layer 115 is provided between the light-emitting unit 106 and the light-emitting unit 108 . The light-emitting unit 106 and the light-emitting unit 108 may have the same configuration or different configurations. For example, it is preferable to use the EL layer 100 shown in Fig. 1 for the light-emitting unit 108 .

[0229] The light-emitting element 250 also has a light-emitting layer 120 and a light-emitting layer 170. The light-emitting unit 106, in addition to the light-emitting layer 120, has a hole injection layer 111, a hole transport layer 112, an electron transport layer 113, and an electron injection layer 114. The light-emitting unit 108, in addition to the light-emitting layer 170 , has a hole injection layer 116, a hole transport layer 117, an electron transport layer 118, and an electron injection layer 11 9.

[0230] The charge generation layer 115 may be a configuration in which an acceptor substance, which is an electron acceptor, is added to a hole-transporting material or a configuration in which a donor substance, which is an electron donor, is added to an electron-transporting material ​It may be. Also, both of these configurations may be laminated.

[0231] When the charge generation layer 115 contains a composite material of an organic compound and an acceptor material, the composite material may be the same composite material as that used for the hole injection layer 111 shown in Embodiment 1. As the organic compound, various compounds such as aromatic amine compounds, carbazole compounds, aromatic hydrocarbons, high molecular compounds (oligomers, dendrimers, polymers, etc.) can be used. Note that as the organic compound, those having a hole mobility of 1×10 cm -6 cm 2 / Vs or more are preferably applied. However, substances other than these may be used as long as they have higher hole transportability than electrons. Since the composite material of the organic compound and the acceptor material is excellent in carrier injection property and carrier transport property, low voltage driving and low current driving can be realized. When the surface on the anode side of the light emitting unit is in contact with the charge generation layer 115 as in the light emitting unit 108, the charge generation layer 115 can also serve as the hole injection layer or the hole transport layer of the light emitting unit. Therefore, the light emitting unit may be configured without providing a hole injection layer or a hole transport layer. In addition, the charge generation layer 115 may be formed as a laminated structure combining a layer containing a composite material of an organic compound and an acceptor material and a layer composed of other materials. For example, it may be formed by combining a layer containing a composite material of an organic compound and an acceptor material and a layer containing one of the compounds selected from electron donating materials and a compound having high electron transportability. Also, a layer containing a composite material of an organic compound and an acceptor material and a layer containing a transparent conductive material may be combined. or a hole transport layer, and the light emitting unit may have a configuration without providing a hole injection layer or a hole transport layer. It may be.

[0232] Note that the charge generation layer 115 may be formed as a laminated structure combining a layer containing a composite material of an organic compound and an acceptor material and a layer composed of other materials. For example, it may be formed by combining a layer containing a composite material of an organic compound and an acceptor material and a layer containing one of the compounds selected from electron donating materials and a compound having high electron transportability. Also, it may be formed by combining a layer containing a composite material of an organic compound and an acceptor material and a layer containing a transparent conductive material. For example, it may be formed by combining a layer containing a composite material of an organic compound and an acceptor material and a layer containing one of the compounds selected from electron donating materials and a compound having high electron transportability. Also, it may be formed by combining a layer containing a composite material of an organic compound and an acceptor material and a layer containing a transparent conductive material. They may be formed together.

[0233] Note that the charge generation layer 115 sandwiched between the light emitting unit 106 and the light emitting unit 108 is an electric When a voltage is applied between the electrode 101 and the electrode 102, it may inject electrons into one light emitting unit and inject holes into the other light emitting unit. For example, in FIG. 3(A), when a voltage is applied so that the potential of the electrode 101 is higher than the potential of the electrode 102, the electric charge generation layer 115 injects electrons into the light emitting unit 106 and injects holes into the light emitting unit 108.

[0234] Note that the charge generation layer 115 preferably has translucency with respect to visible light (specifically, the transmittance of visible light with respect to the charge generation layer 115 is 40% or more) from the viewpoint of light extraction efficiency. Also, the charge generation layer 115 functions even if it has a lower conductivity than a pair of electrodes (electrode 101 and electrode 102).

[0235] By forming the charge generation layer 115 using the above-described materials, an increase in the driving voltage in the case where the light emitting layers are stacked can be suppressed.

[0236] Also, in FIG. 3(A), the light emitting device having two light emitting units has been described, but it can be similarly applied to a light emitting device in which three or more light emitting units are stacked. As shown in the light emitting device 250, by arranging a plurality of light emitting units between a pair of electrodes with a charge generation layer interposed therebetween, high-brightness light emission can be enabled while keeping the current density low, and furthermore a long-life light emitting device can be realized. Also, a light emitting device with low power consumption can be realized.

[0237] ​​​​​At least one of the multiple units has the structure shown in the first embodiment. By applying this composition, a light-emitting element with high luminous efficiency can be provided.

[0238] The light-emitting layer 170 of the light-emitting unit 108 is the same as the light-emitting layer 13 shown in the first embodiment. 0. By doing so, the light emitting element 250 has a high light emitting efficiency. This is suitable as a light emitting element.

[0239] As shown in FIG. 3B, the light-emitting layer 120 of the light-emitting unit 106 is a host The material 121 and the guest material 122 are fluorescent materials. , as explained below.

[0240] <Light Emitting Mechanism of the Light Emitting Layer 120> The light emitting mechanism of the light emitting layer 120 will be described below.

[0241] Electrons injected from a pair of electrodes (electrodes 101 and 102) or a charge generating layer and The guest material 1 and the hole recombine in the light-emitting layer 120 to generate an exciton. Since the host material 121 is present in a large amount compared to 22, the generation of excitons An excited state of the material 121 is formed.

[0242] An exciton is a pair of carriers (electrons and holes). Therefore, the material in which the excitons are generated is in an excited state.

[0243] When the excited state of the formed host material 121 is a singlet excited state, the host material 12 Singlet excitation energy is transferred from the S1 level of 1 to the S1 level of the guest material 122. As a result, the singlet excited state of the guest material 122 is formed.

[0244] Since the guest material 122 is a fluorescent material, when a singlet excited state is formed in the guest material 122, the guest material 122 emits light promptly. In this case, in order to obtain high luminous efficiency, it is preferable that the fluorescence quantum yield of the guest material 122 is high. In addition, in the guest material 122, when carriers recombine and the generated excited state is a singlet excited state, the same applies. Next, the case where a triplet excited state of the host material 121 is formed by carrier recombination will be described. The energy level correlation of the host material 121 and the guest material 122 in this case is shown in Fig. 3(C). Also, the notations and symbols in Fig. 3(C) are as follows. Since it is preferable that the T1 level of the host material 121 is lower than the T1 level of the guest material 122, this case is illustrated in Fig. 3(C), but the T1 level of the host material 121 may be higher than the T1 level of the guest material 122. ·Host(121): Host material 121 ·Guest(122): Guest material 122 (fluorescent material) ·S FH : S1 level of host material 121 ·T FH : T1 level of host material 121

[0245] ·S FG : S1 level of guest material 122 (fluorescent material) ·T FG : T1 level of guest material 122 (fluorescent material) As shown in Fig. 3(C), by triplet-triplet annihilation (TTA), the triplet generated by carrier recombination

[0246]

[0247] ​​​​​​​​​​The excitons interact with each other, transferring excitation energy and exchanging spin angular momentum with each other to result in a reaction that converts to a singlet exciton having the energy of the S1 level (S FH ) of the host material 121 (see TTA in Fig. 3(C)). The singlet excitation energy of the host material 121 is transferred from S to the S1 level (S FH ) of the guest material 122 having lower energy than that (see Route E1 in Fig. 3(C)), forming a singlet excited state of the guest material 122, and the guest material 122 emits light. S1 level (S FG ) of the guest material 122, and an energy transfer occurs (see Route E1 in Fig. 3(C)), forming a singlet excited state of the guest material 122, and the guest material 122 emits light. Note that when the density of triplet excitons in the light-emitting layer 120 is sufficiently high (for example, 1×10

[0248] cm -12 or more), the deactivation of a single triplet exciton can be ignored, and only the reaction by two adjacent triplet excitons can be considered. -3 Moreover, when carriers recombine in the guest material 122 to form a triplet excited state, the energy of the triplet excited state of the guest material 122 is thermally deactivated, making it difficult to utilize for light emission. However, when the T1 level (T ) of the host material 121 is lower than the T1 level (T

[0249] ) of the guest material 122, the triplet excitation energy of the guest material 122 can be transferred from the T1 level (T ) of the guest material 122 to the T1 level (T FH ) of the host material 121 (see Route E2 in Fig. 3(C)), and then utilized for TTA. 22 to the T1 level (T FG ) of the host material 121, and then utilized for TTA. transferred from the T1 level (T FG ) of the guest material 122 to the T1 level (T FH ) of the host material 121 (see Route E2 in Fig. 3(C)), and then utilized for TTA. That is, the host material 121 converts triplet excitation energy into singlet excitation energy by TTA and then utilizes it.

[0250] and then utilizes it. Preferably, it has a function of converting into energy. By doing so, part of the triplet excitation energy generated in the light-emitting layer 120 is converted into singlet excitation energy by TTA in the host material 121, and the singlet excitation energy is transferred to the guest material 122, so that fluorescence can be extracted as light emission. For this purpose, the S1 level (S ) of the host material 121 is preferably higher than the S1 level (S FH ) of the guest material 122. Also, the T1 level (T FG ) of the host material 121 is preferably lower than the T1 level (T ) of the guest material 122. FH ) is preferably lower than the T1 level (T FG ) of the guest material 122. This is preferable.

[0251] In particular, when the T1 level (T FG ) of the guest material 122 is lower than the T1 level (T FH ) of the host material 121, the weight ratio of the host material 121 to the guest material 122 is preferably lower for the guest material 122. Specifically, the content of the guest material 122 is preferably greater than 0 and 0.05 or less in weight ratio to the host material 121. By setting the weight ratio relationship in this way, the probability of carrier recombination in the guest material 122 can be reduced. Also, the probability of energy transfer from the T1 level (T ) of the host material 121 to the T1 level (T FH ) of the guest material 122 can be reduced. to the T1 level (T FG ) of the guest material 122 can be reduced.

[0252] Note that the host material 121 may be composed of a single compound or may be composed of a plurality of compounds. This is acceptable.

[0253] In addition, in each of the above configurations, the guest used in the light-emitting unit 106 and the light-emitting unit 108 The emission colors exhibited by the host materials may be the same or different. For the light-emitting unit 1 06 and the light-emitting unit 108 having a guest material with the function of emitting light of the same color, the light-emitting element 250 preferably becomes a light-emitting element that exhibits high emission luminance at a low current value. Also when the light-emitting unit 106 and the light-emitting unit 108 have a guest material with the function of emitting light of different colors from each other, the light-emitting element 250 preferably becomes a light-emitting element that exhibits multi-color emission. In this case, by using a plurality of light-emitting materials having different emission wavelengths in either one or both of the light-emitting layer 120 and the light-emitting layer 170, the emission spectrum exhibited by the light-emitting element 250 is light in which emissions having different emission peaks are synthesized, so that it becomes an emission spectrum having at least two peaks. The above configuration is also suitable for obtaining white light emission. By making the lights of the light-emitting layer 120 and the light-emitting layer 170 be in a complementary color relationship with each other, white light emission can be obtained. In particular, it is preferable to select a guest material so as to obtain white light emission with high color rendering properties, or emission having at least red, green, and blue. Also, either one or both of the light-emitting layer 120 and the light-emitting layer 170 may be further divided into layers, and different light-emitting materials may be contained in each of the divided layers. That is, either one or both of the light-emitting layer 120 and the light-emitting layer 170 may be composed of a plurality of layers of two or more layers. For example, when the first light-emitting layer and the second light-emitting layer are laminated in order from the hole transport layer side to form a light-emitting layer, a substance having hole transport properties is used as the host material of the first light-emitting layer, and so on.

[0254] The above configuration is also suitable for obtaining white light emission. By making the lights of the light-emitting layer 120 and the light-emitting layer 170 be in a complementary color relationship with each other, white light emission can be obtained. In particular, it is preferable to select a guest material so as to obtain white light emission with high color rendering properties, or emission having at least red, green, and blue. Also, either one or both of the light-emitting layer 120 and the light-emitting layer 170 may be further divided into layers, and different light-emitting materials may be contained in each of the divided layers. That is, either one or both of the light-emitting layer 120 and the light-emitting layer 170 may be composed of a plurality of layers of two or more layers. For example, when the first light-emitting layer and the second light-emitting layer are laminated in order from the hole transport layer side to form a light-emitting layer, a substance having hole transport properties is used as the host material of the first light-emitting layer, and so on.

[0255] Also, either one or both of the light-emitting layer 120 and the light-emitting layer 170 may be further divided into layers, and different light-emitting materials may be contained in each of the divided layers. That is, either one or both of the light-emitting layer 120 and the light-emitting layer 170 may be composed of a plurality of layers of two or more layers. For example, when the first light-emitting layer and the second light-emitting layer are laminated in order from the hole transport layer side to form a light-emitting layer, a substance having hole transport properties is used as the host material of the first light-emitting layer, and so on. For example, when the first light-emitting layer and the second light-emitting layer are laminated in order from the hole transport layer side to form a light-emitting layer, a substance having hole transport properties is used as the host material of the first light-emitting layer, and There is a configuration in which a substance having electron transporting properties is used as the host material of the second light emitting layer. This In this case, the light emitting materials of the first light emitting layer and the second light emitting layer may be the same material or different materials, and may be materials having a function of emitting light of the same color or materials having a function of emitting light of different colors. By using a configuration having a plurality of light emitting materials having functions of emitting lights of different colors, it is possible to obtain white light with high color rendering properties composed of three primary colors or four or more light emitting colors. Also, when the guest materials of the light emitting unit 106 and the light emitting unit 108 have different light emitting colors, it is preferable that the light emitted from the light emitting layer 120 has a light emission peak on the shorter wavelength side than the light emitted from the light emitting layer 170. A light emitting device using a material having a high triplet excitation energy level tends to have rapid luminance degradation. Therefore, by using TTA in the light emitting layer that emits short-wavelength light, a light emitting device with little luminance degradation can be provided. Also, when the guest materials of the light emitting unit 106 and the light emitting unit 108 have different light emitting colors, it is preferable that the light emitted from the light emitting layer 120 has a light emission peak on the shorter wavelength side than the light emitted from the light emitting layer 170. A light emitting device using a material having a high triplet excitation energy level tends to have rapid luminance degradation. Therefore, by using TTA in the light emitting layer that emits short-wavelength light, a light emitting device with little luminance degradation can be provided. Also, when the guest materials of the light emitting unit 106 and the light emitting unit 108 have different light emitting colors, it is preferable that the light emitted from the light emitting layer 120 has a light emission peak on the shorter wavelength side than the light emitted from the light emitting layer 170. A light emitting device using a material having a high triplet excitation energy level tends to have rapid luminance degradation. Therefore, by using TTA in the light emitting layer that emits short-wavelength light, a light emitting device with little luminance degradation can be provided. Also, when the guest materials of the light emitting unit 106 and the light emitting unit 108 have different light emitting colors, it is preferable that the light emitted from the light emitting layer 120 has a light emission peak on the shorter wavelength side than the light emitted from the light emitting layer 170. A light emitting device using a material having a high triplet excitation energy level tends to have rapid luminance degradation. Therefore, by using TTA in the light emitting layer that emits short-wavelength light, a light emitting device with little luminance degradation can be provided.

[0256] Next, a configuration example different from the light emitting device shown in FIG. 3 will be described with reference to FIGS. 4(A), (B), and (C). FIG. 4(A) is a schematic cross-sectional view of the light emitting device 252. The light emitting device 252 shown in FIG. 4(A) has a structure in which an EL layer 110 is sandwiched between a pair of electrodes (electrode 101 and electrode 102). In the light emitting device 252, it is assumed that the electrode 101 functions as an anode and the electrode 102 functions as a cathode, and the following description will be made. However, the configuration of the light emitting device 252 may be reversed. Next, a configuration example different from the light emitting device shown in FIG. 3 will be described with reference to FIGS. 4(A), (B), and (C). Next, a configuration example different from the light emitting device shown in FIG. 3 will be described with reference to FIGS. 4(A), (B), and (C).

[0257] <Configuration Example 2 of Light Emitting Device> Next, a configuration example different from the light emitting device shown in FIG. 3 will be described with reference to FIGS. 4(A), (B), and (C). Next, a configuration example different from the light emitting device shown in FIG. 3 will be described with reference to FIGS. 4(A), (B), and (C).

[0258] FIG. 4(A) is a schematic cross-sectional view of the light emitting device 252.

[0259] The light emitting device 252 shown in FIG. 4(A) has a structure in which an EL layer 110 is sandwiched between a pair of electrodes (electrode 101 and electrode 102). In the light emitting device 252, it is assumed that the electrode 101 functions as an anode and the electrode 102 functions as a cathode, and the following description will be made. However, the configuration of the light emitting device 252 may be reversed. The light emitting device 252 shown in FIG. 4(A) has a structure in which an EL layer 110 is sandwiched between a pair of electrodes (electrode 101 and electrode 102). In the light emitting device 252, it is assumed that the electrode 101 functions as an anode and the electrode 102 functions as a cathode, and the following description will be made. However, the configuration of the light emitting device 252 may be reversed. The light emitting device 252 shown in FIG. 4(A) has a structure in which an EL layer 110 is sandwiched between a pair of electrodes (electrode 101 and electrode 102). In the light emitting device 252, it is assumed that the electrode 101 functions as an anode and the electrode 102 functions as a cathode, and the following description will be made. However, the configuration of the light emitting device 252 may be reversed. The light emitting device 252 shown in FIG. 4(A) has a structure in which an EL layer 110 is sandwiched between a pair of electrodes (electrode 101 and electrode 102). In the light emitting device 252, it is assumed that the electrode 101 functions as an anode and the electrode 102 functions as a cathode, and the following description will be made. However, the configuration of the light emitting device 252 may be reversed.

[0260] Further, the EL layer 110 has a light-emitting layer 180, and the light-emitting layer 180 has a light-emitting layer 120 and a light-emitting layer 170. Also, in the light-emitting element 252, as the EL layer 110, in addition to the light-emitting layer, a hole injection layer 111, a hole transport layer 112, an electron transport layer 118, and an electron injection layer 119 are illustrated, but these laminated structures are merely examples, and the configuration of the EL layer 11 0 in the light-emitting element 252 is not limited thereto. For example, in the EL layer 110, the lamination order of the above layers may be changed. Alternatively, in the EL layer 110, functional layers other than the above layers may be provided. Examples of the functional layer include a configuration having a function of reducing the injection barrier of holes or electrons, a function of improving the transportability of holes or electrons, a function of inhibiting the transportability of holes or electrons, and a function of generating holes or electrons.

[0261] Also, as shown in FIG. 4(B), the light-emitting layer 120 has a host material 121 and a guest material 1 22. Further, the light-emitting layer 170 has a host material 171 and a guest material 172. The host material 171 has an organic compound 171_1 and an organic compound 171_2. Note that the guest material 122 is a fluorescent material and the guest material 172 is a phosphorescent material, which will be described below.

[0262] ≪Light-emitting mechanism of the light-emitting layer 180≫ The light-emitting mechanism of the light-emitting layer 120 is the same as the light-emitting mechanism of the light-emitting layer 120 shown in FIG. 3. Also, the light-emitting mechanism of the light-emitting layer 170 is the same as the light-emitting mechanism of the light-emitting layer 130 shown in Embodiment 1. That is, the host material 171, the organic compound 171_1, the organic compound 171_ 2, and the guest material 172 are the host material 131, the organic compound 131_1, and the organic compound ​​The object 131_2 and the guest material 132 have the same configuration respectively.

[0263] As shown in the light-emitting element 252, when the light-emitting layer 120 and the light-emitting layer 170 are in contact with each other, at the interface between the light-emitting layer 120 and the light-emitting layer 170, energy transfer from the exciplex to the host material 121 of the light-emitting layer 120 (especially energy transfer of the triplet excitation level) occurs. Even if it occurs, the triplet excitation energy can be converted into light emission in the light-emitting layer 120.

[0264] Note that it is preferable that the T1 level of the host material 121 of the light-emitting layer 120 is lower than the T1 levels of the organic compounds 171_1 and 171_2 included in the light-emitting layer 170. Also, in the light-emitting layer 120, it is preferable that the S1 level of the host material 121 is higher than the S1 level of the guest material 122 (fluorescent material), and the T1 level of the host material 121 is lower than the T1 level of the guest material 122 (fluorescent material).

[0265] Specifically, the correlation of the energy levels in the case of using TTA for the light-emitting layer 120 and using ExTET for the light-emitting layer 170 is shown in FIG. 4(C). Note that the notations and symbols in FIG. 4(C) are as follows. ·Fluorescence EML(120): Light-emitting layer 120 (fluorescent light-emitting layer) ·Phosphorescence EML(170): Light-emitting layer 170 (phosphorescent light-emitting layer) ·Host(121): Host material 121 ·Guest(122): Guest material 122 (fluorescent material) ·Host(171_1): Host material (organic compound 171_1) ·Guest(172): Guest material 172 (phosphorescent material) ·Exciplex: Excimer (Organic Compound 171_1 and Organic Compound 171_2) ·S FH : S1 level of host material 121 ·T FH : T1 level of host material 121 ·S FG : S1 level of guest material 122 (fluorescent material) ·T FG : T1 level of guest material 122 (fluorescent material) ·S PH : S1 level of host material (Organic Compound 171_1) ·T PH : T1 level of host material (Organic Compound 171_1) ·T PG : T1 level of guest material 172 (phosphorescent material) ·S E : S1 level of exciplex ·T E : T1 level of exciplex

[0266] As shown in Fig. 4(C), since the exciplex exists only in the excited state, exciton diffusion between the exciplex and the exciplex is unlikely to occur. Also, since the excitation energy levels (S , T E ) of the exciplex are lower than the excitation energy levels (S E ) of the organic compound 171_1 in the light-emitting layer 170 (i.e., the host material of the phosphorescent material), energy diffusion from the exciplex to the organic compound 171_ 1 does not occur either. That is, in the phosphorescent light-emitting layer (light-emitting layer 170), since the exciton diffusion distance of the exciplex is short, it is possible to maintain the efficiency of the phosphorescent light-emitting layer (light-emitting layer 170). Also, at the interface between the fluorescent light-emitting layer (light-emitting layer 120) and the phosphorescent light-emitting layer (light-emitting layer 170), even if a part of the triplet excitation energy of the exciplex in the phosphorescent light-emitting layer (light-emitting layer 170) diffuses into the fluorescent light-emitting layer (light-emitting layer 120), the fluorescence generated by that diffusion PH 、T PH ) is lower than the excitation energy levels of the organic compound 171_ 1 in the phosphorescent light-emitting layer (light-emitting layer 170), so energy diffusion from the exciplex to the organic compound 171_ 1 does not occur either. That is, in the phosphorescent light-emitting layer (light-emitting layer 170), since the exciton diffusion distance of the exciplex is short, it is possible to maintain the efficiency of the phosphorescent light-emitting layer (light-emitting layer 170). Also, at the interface between the fluorescent light-emitting layer (light-emitting layer 120) and the phosphorescent light-emitting layer (light-emitting layer 170), even if a part of the triplet excitation energy of the exciplex in the phosphorescent light-emitting layer (light-emitting layer 170) diffuses into the fluorescent light-emitting layer (light-emitting layer 120), the fluorescence generated by that diffusion can be maintained. Also, at the interface between the fluorescent light-emitting layer (light-emitting layer 120) and the phosphorescent light-emitting layer (light-emitting layer 170), even if a part of the triplet excitation energy of the exciplex in the phosphorescent light-emitting layer (light-emitting layer 170) diffuses into the fluorescent light-emitting layer (light-emitting layer 120), the fluorescence generated by that diffusion layer (light-emitting layer 120) is small, so it does not affect the efficiency of the fluorescent light-emitting layer (light-emitting layer 120). layer (light-emitting layer 120) is small, so it does not affect the efficiency of the fluorescent light-emitting layer (light-emitting layer 120). Since the triplet excitation energy of the optical layer 120 is converted into light emission through TTA, energy loss can be reduced. It becomes possible to reduce energy loss.

[0267] As described above, the light-emitting element 252 utilizes ExTET in the light-emitting layer 170 and TTA in the light-emitting layer 120, so that energy loss is reduced, and a light-emitting element with high luminous efficiency can be obtained. Also, as shown in the light-emitting element 252, when the light-emitting layer 120 and the light-emitting layer 170 are in contact with each other, the above energy loss is reduced, and the number of layers of the EL layer 110 can be reduced. Therefore, a light-emitting element with low manufacturing cost can be obtained. It can be a high-luminance-efficiency light-emitting element. Moreover, as shown in the light-emitting element 252, when the light-emitting layer 120 and the light-emitting layer 170 are in contact with each other, the above energy loss is reduced, and the number of layers of the EL layer 110 can be reduced. Therefore, a light-emitting element with low manufacturing cost can be obtained. In addition, when the light-emitting layer 120 and the light-emitting layer 170 are in contact with each other, the above energy loss is reduced, and the number of layers of the EL layer 110 can be reduced. Therefore, a light-emitting element with low manufacturing cost can be obtained. In addition, when the light-emitting layer 120 and the light-emitting layer 170 are in contact with each other, the above energy loss is reduced, and the number of layers of the EL layer 110 can be reduced. Therefore, a light-emitting element with low manufacturing cost can be obtained. It can be a light-emitting element with low manufacturing cost.

[0268] Note that the light-emitting layer 120 and the light-emitting layer 170 may not be in contact with each other. In this case, energy transfer (particularly triplet energy transfer) by the Dexter mechanism from the excited state of the organic compound 171_1, organic compound 171_2, or guest material 172 (phosphorescent material) generated in the light-emitting layer 170 to the host material 121 or guest material 122 (fluorescent material) in the light-emitting layer 120 can be prevented. Therefore, the layer provided between the light-emitting layer 120 and the light-emitting layer 170 may have a thickness of about several nanometers. Specifically, when it is 1 nm or more and 5 nm or less, an increase in the driving voltage can be suppressed, which is preferable. In this case, energy transfer (particularly triplet energy transfer) by the Dexter mechanism from the excited state of the organic compound 171_1, organic compound 171_2, or guest material 172 (phosphorescent material) generated in the light-emitting layer 170 to the host material 121 or guest material 122 (fluorescent material) in the light-emitting layer 120 can be prevented. In this case, energy transfer (particularly triplet energy transfer) by the Dexter mechanism from the excited state of the organic compound 171_1, organic compound 171_2, or guest material 172 (phosphorescent material) generated in the light-emitting layer 170 to the host material 121 or guest material 122 (fluorescent material) in the light-emitting layer 120 can be prevented. In this case, energy transfer (particularly triplet energy transfer) by the Dexter mechanism from the excited state of the organic compound 171_1, organic compound 171_2, or guest material 172 (phosphorescent material) generated in the light-emitting layer 170 to the host material 121 or guest material 122 (fluorescent material) in the light-emitting layer 120 can be prevented. In this case, energy transfer (particularly triplet energy transfer) by the Dexter mechanism from the excited state of the organic compound 171_1, organic compound 171_2, or guest material 172 (phosphorescent material) generated in the light-emitting layer 170 to the host material 121 or guest material 122 (fluorescent material) in the light-emitting layer 120 can be prevented. In this case, energy transfer (particularly triplet energy transfer) by the Dexter mechanism from the excited state of the organic compound 171_1, organic compound 171_2, or guest material 172 (phosphorescent material) generated in the light-emitting layer 170 to the host material 121 or guest material 122 (fluorescent material) in the light-emitting layer 120 can be prevented. In this case, energy transfer (particularly triplet energy transfer) by the Dexter mechanism from the excited state of the organic compound 171_1, organic compound 171_2, or guest material 172 (phosphorescent material) generated in the light-emitting layer 170 to the host material 121 or guest material 122 (fluorescent material) in the light-emitting layer 120 can be prevented.

[0269] The layer provided between the light-emitting layer 120 and the light-emitting layer 170 may be composed of a single material, or may contain both a hole-transporting material and an electron-transporting material. When composed of a single material, a bipolar material may be used. Here, the bipolar material refers to a material that can transport both electrons and holes. The layer provided between the light-emitting layer 120 and the light-emitting layer 170 may be composed of a single material, or may contain both a hole-transporting material and an electron-transporting material. When composed of a single material, a bipolar material may be used. Here, the bipolar material refers to a material that can transport both electrons and holes. When composed of a single material, a bipolar material may be used. Here, the bipolar material refers to a material that can transport both electrons and holes. refers to a material with a mobility ratio of 100 or less. Also, a hole transporting material or an electron transporting material, etc. may be used. Alternatively, at least one of them may be formed of the same material as the host material (organic compound 171_1 or organic compound 171_2) of the light emitting layer 170. This makes it easier to fabricate the light emitting device and also reduces the driving voltage. Furthermore, an exciplex may be formed between the hole transporting material and the electron transporting material, which can effectively prevent the diffusion of excitons. Specifically, the energy transfer from the excited state of the host material (organic compound 171_1 or organic compound 171_2) or the guest material 172 (phosphorescent material) of the light emitting layer 170 to the host material 121 or the guest material 122 (fluorescent material) of the light emitting layer 120 can be prevented. In the light emitting device 252, although the light emitting layer 170 is described as being on the hole transporting layer 112 side and the light emitting layer 120 is on the electron transporting layer 118 side, the light emitting device of one aspect of the present invention is not limited to this, and the light emitting layer 170 may be on the electron transporting layer 118 side and the light emitting layer 120 may be on the hole transporting layer 112 side. Moreover, in the light emitting device 252, the recombination region of carriers is preferably formed with a certain degree of distribution. For this reason, in the light emitting layer 120 or the light emitting layer 170, it is preferable to have appropriate carrier trapping properties. In particular, it is preferable that the guest material 172 (phosphorescent material) of the light emitting layer 170 has hole trapping properties. Therefore, as the light emitting layer 170, the configuration of the light emitting layer 130 shown in Embodiment 1 is preferable. Also, in the light emitting device 252, although the light emitting layer 170 is described as being on the hole transporting layer 112 side and the light emitting layer 120 is on the electron transporting layer 118 side, the light emitting device of one aspect of the present invention is not limited to this, and the light emitting layer 170 may be on the electron transporting layer 118 side and the light emitting layer 120 may be on the hole transporting layer 112 side. Moreover, in the light emitting device 252, the recombination region of carriers is preferably formed with a certain degree of distribution. For this reason, in the light emitting layer 120 or the light emitting layer 170, it is preferable to have appropriate carrier trapping properties. In particular, it is preferable that the guest material 172 (phosphorescent material) of the light emitting layer 170 has hole trapping properties. Therefore, as the light emitting layer 170, the configuration of the light emitting layer 130 shown in Embodiment 1 is preferable. Also, in the light emitting device 252, although the light emitting layer 170 is described as being on the hole transporting layer 112 side and the light emitting layer 120 is on the electron transporting layer 118 side, the light emitting device of one aspect of the present invention is not limited to this, and the light emitting layer 170 may be on the electron transporting layer 118 side and the light emitting layer 120 may be on the hole transporting layer 112 side. Moreover, in the light emitting device 252, the recombination region of carriers is preferably formed with a certain degree of distribution. For this reason, in the light emitting layer 120 or the light emitting layer 170, it is preferable to have appropriate carrier trapping properties. In particular, it is preferable that the guest material 172 (phosphorescent material) of the light emitting layer 170 has hole trapping properties. Therefore, as the light emitting layer 170, the configuration of the light emitting layer 130 shown in Embodiment 1 is preferable. Also, in the light emitting device 252, although the light emitting layer 170 is described as being on the hole transporting layer 112 side and the light emitting layer 120 is on the electron transporting layer 118 side, the light emitting device of one aspect of the present invention is not limited to this, and the light emitting layer 170 may be on the electron transporting layer 118 side and the light emitting layer 120 may be on the hole transporting layer 112 side. Moreover, in the light emitting device 252, the recombination region of carriers is preferably formed with a certain degree of distribution. For this reason, in the light emitting layer 120 or the light emitting layer 170, it is preferable to have appropriate carrier trapping properties. In particular, it is preferable that the guest material 172 (phosphorescent material) of the light emitting layer 170 has hole trapping properties. Therefore, as the light emitting layer 170, the configuration of the light emitting layer 130 shown in Embodiment 1 is preferable.

[0270] Also, in the light emitting device 252, although the light emitting layer 170 is described as being on the hole transporting layer 112 side and the light emitting layer 120 is on the electron transporting layer 118 side, the light emitting device of one aspect of the present invention is not limited to this, and the light emitting layer 170 may be on the electron transporting layer 118 side and the light emitting layer 120 may be on the hole transporting layer 112 side. Moreover, in the light emitting device 252, the recombination region of carriers is preferably formed with a certain degree of distribution. For this reason, in the light emitting layer 120 or the light emitting layer 170, it is preferable to have appropriate carrier trapping properties. In particular, it is preferable that the guest material 172 (phosphorescent material) of the light emitting layer 170 has hole trapping properties. Therefore, as the light emitting layer 170, the configuration of the light emitting layer 130 shown in Embodiment 1 is preferable. Also, in the light emitting device 252, although the light emitting layer 170 is described as being on the hole transporting layer 112 side and the light emitting layer 120 is on the electron transporting layer 118 side, the light emitting device of one aspect of the present invention is not limited to this, and the light emitting layer 170 may be on the electron transporting layer 118 side and the light emitting layer 120 may be on the hole transporting layer 112 side. Moreover, in the light emitting device 252, the recombination region of carriers is preferably formed with a certain degree of distribution. For this reason, in the light emitting layer 120 or the light emitting layer 170, it is preferable to have appropriate carrier trapping properties. In particular, it is preferable that the guest material 172 (phosphorescent material) of the light emitting layer 170 has hole trapping properties. Therefore, as the light emitting layer 170, the configuration of the light emitting layer 130 shown in Embodiment 1 is preferable.

[0271] In the light emitting device 252, although the light emitting layer 170 is described as being on the hole transporting layer 112 side and the light emitting layer 120 is on the electron transporting layer 118 side, the light emitting device of one aspect of the present invention is not limited to this, and the light emitting layer 170 may be on the electron transporting layer 118 side and the light emitting layer 120 may be on the hole transporting layer 112 side. Moreover, in the light emitting device 252, the recombination region of carriers is preferably formed with a certain degree of distribution. For this reason, in the light emitting layer 120 or the light emitting layer 170, it is preferable to have appropriate carrier trapping properties. In particular, it is preferable that the guest material 172 (phosphorescent material) of the light emitting layer 170 has hole trapping properties. Therefore, as the light emitting layer 170, the configuration of the light emitting layer 130 shown in Embodiment 1 is preferable. In the light emitting device 252, although the light emitting layer 170 is described as being on the hole transporting layer 112 side and the light emitting layer 120 is on the electron transporting layer 118 side, the light emitting device of one aspect of the present invention is not limited to this, and the light emitting layer 170 may be on the electron transporting layer 118 side and the light emitting layer 120 may be on the hole transporting layer 112 side. Moreover, in the light emitting device 252, the recombination region of carriers is preferably formed with a certain degree of distribution. For this reason, in the light emitting layer 120 or the light emitting layer 170, it is preferable to have appropriate carrier trapping properties. In particular, it is preferable that the guest material 172 (phosphorescent material) of the light emitting layer 170 has hole trapping properties. Therefore, as the light emitting layer 170, the configuration of the light emitting layer 130 shown in Embodiment 1 is preferable. In the light emitting device 252, although the light emitting layer 170 is described as being on the hole transporting layer 112 side and the light emitting layer 120 is on the electron transporting layer 118 side, the light emitting device of one aspect of the present invention is not limited to this, and the light emitting layer 170 may be on the electron transporting layer 118 side and the light emitting layer 120 may be on the hole transporting layer 112 side.

[0272] Note that it is preferable that the light emission from the light-emitting layer 120 has a peak of light emission on the shorter wavelength side than the light emission from the light-emitting layer 170. A light-emitting device using a phosphorescent material that exhibits short-wavelength light emission tends to have rapid luminance degradation. Therefore, by making the short-wavelength light emission fluorescence, a light-emitting device with little luminance degradation can be provided. Also, by obtaining light with different emission wavelengths from the light-emitting layer 120 and the light-emitting layer 170, a multi-color light-emitting device can be formed. In this case, since the emission spectrum is light in which emissions having different emission peaks are synthesized, the emission spectrum has at least two maxima.

[0273] Further, the above configuration is also suitable for obtaining white light emission. By making the light from the light-emitting layer 120 and the light-emitting layer 170 be in a complementary color relationship with each other, white light emission can be obtained.

[0274] In addition, by using a plurality of light-emitting materials having different emission wavelengths in either one or both of the light-emitting layer 120 and the light-emitting layer 170, white light emission with high color rendering properties composed of three primary colors or four or more emission colors can also be obtained. In this case, the light-emitting layer may be further divided into layers, and different light-emitting materials may be contained in each of the divided layers.

[0275]

[0276] <Examples of materials that can be used in the light-emitting layer> Next, the materials that can be used in the light-emitting layer 120 and the light-emitting layer 170 will be described below.

[0277] ≪Materials that can be used in the light-emitting layer 120≫ In the light-emitting layer 120, the host material 121 is present in the largest amount by weight ratio, and the guest material 122 The fluorescent material is dispersed in the host material 121. The S1 level of the host material 121 is The S1 level of the host material 121 is higher than the S1 level of the fluorescent material 122. It is preferable that the T1 level is lower than the T1 level of the photoresist material 122 (fluorescent material).

[0278] In the light-emitting layer 120, the guest material 122 is not particularly limited, but may be anthracene. Derivatives, tetracene derivatives, chrysene derivatives, phenanthrene derivatives, pyrene derivatives, Rylene derivatives, stilbene derivatives, acridone derivatives, coumarin derivatives, phenoxazine Derivatives, phenothiazine derivatives, etc. are preferred, and the following materials can be used, for example: .

[0279] Specifically, 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: PAPP2 BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoro 1,6-Pyrene-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn) , N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H -fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMem FLPAPrn), N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl )phenyl]-N,N'-bis(4-tert-butylphenyl)pyrene-1,6-diazo 1,6tBu-FLPAPrn, N,N'-diphenyl-N,N'-bis(1,6tBu-FLPAPrn) [4-(9-phenyl-9H-fluoren-9-yl)phenyl]-3,8-dicyclohexyl Xylpyrilene-1,6-diamine (abbreviation: ch-1,6FLPAPrn), N,N’-bi s[4-(9H-carbazol-9-yl)phenyl]-N,N’-diphenylstilb ene-4,4’-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl) -4’-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA) , 4-(9H-carbazol-9-yl)-4’-(9,10-diphenyl-2-anth ryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4- (10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine (abbre viation: 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-diyl-di-4,1-phenylene) bis[N,N’,N’-triphenyl-1,4-phenylenediamine](abbreviation: DPAB PA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)ph enyl]-9H-carbazole-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’’’-octaphenyldibenz[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: 2 PCAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anth ryl]-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPh A), 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'-bip henyl-2-yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N-f henylanthracen-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenyl anthracen-9-amine (abbreviation: DPhAPhA), coumarin 6, coumarin 545T , N,N'-diphenylquinacridone (abbreviation: DPQd), rubrene, 2,8-di-te rt-butyl-5,11-bis(4-tert-butylphenyl)-6,12-diphenyl tetracene (abbreviation: TBRb), Nile Red, 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-methyl phenyl)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-i lidene)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}p ropanedinitrile (abbreviation: BisDCJTM), 5,10,15,20-tetraphenyl bisbenzo[5,6]indeno[1,2,3-cd:1’,2’,3’-lm]perylene , and the like.

[0280] In addition, in the light-emitting layer 120, materials that can be used as the host material 121 are not particularly limited. For example, tris(8-quinolinolato)aluminum(III) (abbreviation :Alq), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq3), bis(10-hydroxybenzo[h]quinolinato)beryllium(II)( Abbreviation: BeBq2), 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), bis[2-(2-benzothiazolyl)phenolato]zinc(II)( abbreviation: ZnBTZ), etc. metal complexes, 2-(4-biphenylyl)-5-(4-tert- butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5 -(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 3-(4-biphenylyl)-4-phenyl-5-(4-te rt-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 2,2’,2’ ’-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole le) (abbreviation: TPBI), bathophenanthroline (abbreviation: BPhen), bathocuproine (abbreviation: BCP), 9-[4-(5-phenyl-1,3,4-oxadiazol-2- yl)phenyl]-9H-carbazole (abbreviation: CO11), etc. heterocyclic compounds, 4,4 ’-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB or also α-NPD), N,N’-bis(3-methylphenyl)-N,N’-diphenyl-[1 ,1’-biphenyl]-4,4’-diamine (abbreviation: TPD), 4,4’-bis[N-( spiro-9,9’-bifluorene-2-yl)-N-phenylamino]biphenyl (abbreviation : BSPB), etc. aromatic amine compounds. Also, anthracene derivatives, phen Nanthrene derivatives, pyrene derivatives, chrysene derivatives, dibenzo[g,p]chrysene derivatives Examples thereof include condensed polycyclic aromatic compounds such as (abbreviation: DPAnth), N,N-diphenyl-9-[4-(10-phenyl-9-anth thryl)phenyl]-9H-carbazole-3-amine (abbreviation: CzA1PA), 4-( 10-phenyl-9-anthryl)triphenylamine (abbreviation: DPhPA), 4-(9 H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenyl lamine (abbreviation: YGAPA), N,9-diphenyl-N-[4-(10-phenyl-9 -anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: PCAPA), N ,9-diphenyl-N-{4-[4-(10-phenyl-9-anthryl)phenyl]f enyl}-9H-carbazole-3-amine (abbreviation: PCAPBA), N,9-diphen yl-N-(9,10-diphenyl-2-anthryl)-9H-carbazole-3-amine (abbreviation: 2PCAPA), 6,12-dimethoxy-5,11-diphenylchrysene, N, N,N',N',N'',N'',N''',N''' - octaphenyldibenzo[g, p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), 9-[4-(1 0-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: CzPA), 3,6-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H -carbazole (abbreviation: DPCzPA), 9,10-bis(3,5-diphenylphenyl )anthracene (abbreviation: DPPA), 9,10-di(2-naphthyl)anthracene (abbreviation : DNA), 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation : t-BuDNA), 9,9'-bianthryl (abbreviation: BANT), 9,9'-(stilbene ben-3,3'-diyl)diphenanthrene (abbreviation: DPNS), 9,9'-(stilbene ne-4,4'-diyl)diphenanthrene (abbreviation: DPNS2), 1,3,5-tri(1 -pyrenyl)benzene (abbreviation: TPB3), etc. can be mentioned. Also, from these and among known substances, a substance having an energy gap larger than the energy gap of the guest material 122 above can be selected and used singly or in combination of two or more.

[0281] Note that the light-emitting layer 120 can also be composed of two or more layers. For example, when the first light-emitting layer and the second light-emitting layer are laminated in order from the hole-transporting layer side to form the light-emitting layer 120, a substance having hole-transporting properties is used as the host material of the first light-emitting layer, and a substance having electron-transporting properties is used as the host material of the second light-emitting layer and there are configurations such as this.

[0282] Also, in the light-emitting layer 120, the host material 121 may be composed of one compound or may be composed of a plurality of compounds. Alternatively, in the light-emitting layer 120, it may have a material other than the host material 121 and the guest material 122.

[0283] ≪Materials that can be used for the light-emitting layer 170≫ As materials that can be used for the light-emitting layer 170, the materials that can be used for the light-emitting layer 13 0 shown in the previous Embodiment 1 may be adopted. By doing so, a light-emitting element with high luminous efficiency can be fabricated.

[0284] Also, there is no limitation on the emission color of the light-emitting materials included in the light-emitting layer 120 and the light-emitting layer 170, and They may be the same or different from each other. The light emitted from each is mixed and extracted outside the element. Therefore, for example, when the emission colors of both are complementary to each other, the light-emitting element can emit white light. Considering the reliability of the light-emitting element, it is preferable that the emission peak wavelength of the light-emitting material contained in the light-emitting layer 120 is shorter than that of the light-emitting material contained in the light-emitting layer 170.

[0285] Note that the light-emitting unit 106, the light-emitting unit 108, and the charge generation layer 115 can be formed by methods such as vapor deposition ( including vacuum vapor deposition), inkjet method, coating method, gravure printing, etc.

[0286] As described above, the configuration shown in this embodiment can be appropriately combined with the configurations shown in other embodiments and used.

[0287] (Embodiment 3) In this embodiment, an example of a light-emitting element having a configuration different from the configurations shown in Embodiment 1 and Embodiment 2 will be described below with reference to FIGS. 5 to 8.

[0288] <Configuration Example 1 of Light-Emitting Element> FIGS. 5(A) and 5(B) are cross-sectional views showing a light-emitting element according to an aspect of the present invention. In FIGS. 5(A )(B), portions having the same functions as the reference numerals shown in FIG. 1(A) may be denoted by the same hatch pattern, and the reference numerals may be omitted. Also, portions having the same functions may be denoted by the same reference numerals, and detailed descriptions thereof may be omitted.

[0289] The light-emitting elements 260a and 260b shown in FIGS. 5(A) and 5(B) may be bottom emission type light-emitting elements that extract light on the substrate 200 side, and between the substrate 200 and A top emission type light emitting element that emits light in the opposite direction may also be used. Note that one aspect of the present invention is not limited to this, and a dual emission type light emitting element that emits light from both above and below the substrate 200 may also be used. .

[0290] When the light emitting elements 260a and 260b are of the bottom emission type, the electrode 1 01 preferably has a function of transmitting light. Further, the electrode 102 preferably has a function of reflecting light. Alternatively, when the light emitting elements 260a and 260b are of the top emission type, the electrode 101 preferably has a function of reflecting light. Further, the electrode 102 preferably has a function of transmitting light.

[0291] The light emitting elements 260a and 260b have an electrode 101 and an electrode 102 on the substrate 200. Further, between the electrode 101 and the electrode 102, there are a light emitting layer 123B, a light emitting layer 123 G, and a light emitting layer 123R. Further, there are a hole injection layer 111, a hole transport layer 112, an electron transport layer 118, and an electron injection layer 119.

[0292] Further, the light emitting element 260b has, as a part of the configuration of the electrode 101, a conductive layer 101a, a conductive layer 101b on the conductive layer 101a, and a conductive layer 101c under the conductive layer 101a. That is, the light emitting element 260b has a configuration of the electrode 101 in which the conductive layer 101a is sandwiched between the conductive layer 101b and the conductive layer 101c.

[0293] In the light emitting element 260b, the conductive layer 101b and the conductive layer 101c are formed of different materials. It may be formed or may be formed of the same material. When the electrode 101 has a structure sandwiched between the same conductive materials, it is preferable because the pattern formation by the etching process in the process of forming the electrode 101 becomes easy. In the light-emitting element 260b, it may have a structure having only one of the conductive layer 101b or the conductive layer 101c. For the conductive layers 101a, 101b, and 101c included in the electrode 101, the same configuration and materials as those of the electrode 101 or the electrode 102 shown in the first embodiment can be used.

[0294] In FIGS. 5(A) and 5(B), there is a partition wall 145 between the regions 221B, 221G, and 221R sandwiched between the electrode 101 and the electrode 102. The partition wall 145 has insulating properties. The partition wall 145 covers the end portion of the electrode 101 and has an opening overlapping with the electrode. By providing the partition wall 145, the electrodes 101 on the substrate 200 in each region can be separated into island shapes. The light-emitting layer 123B and the light-emitting layer 123G may have overlapping regions with each other in a region overlapping with the partition wall 145. Alternatively, the light-emitting layer 123G and the light-emitting layer 123R may have overlapping regions with each other in a region overlapping with the partition wall 145. Alternatively, the light-emitting layer 123R and the light-emitting layer 123B may have overlapping regions with each other in a region overlapping with the partition wall 145.

[0295] The partition wall 145 only needs to be insulating and can be formed using an inorganic material or an organic material. The partition wall 145 only needs to be insulating and can be formed using an inorganic material or an organic material. It can be formed using an inorganic material or an organic material.

[0296] In FIGS. 5(A) and 5(B), there is a partition wall 145 between the regions 221B, 221G, and 221R sandwiched between the electrode 101 and the electrode 102. The partition wall 145 has insulating properties. The partition wall 145 covers the end of the electrode 101 and has an opening overlapping with the electrode. By providing the partition wall 145, the electrodes 101 on the substrate 200 in each region can be separated into island shapes. It becomes possible to separate them.

[0297] Note that the light-emitting layer 123B and the light-emitting layer 123G may have overlapping regions with each other in a region overlapping with the partition wall 145. Alternatively, the light-emitting layer 123G and the light-emitting layer 123R may have overlapping regions with each other in a region overlapping with the partition wall 145. Alternatively, the light-emitting layer 123R and the light-emitting layer 123B may have overlapping regions with each other in a region overlapping with the partition wall 145. Alternatively, the light-emitting layer 123R and the light-emitting layer 123B may have overlapping regions with each other in a region overlapping with the partition wall 145. They may have overlapping regions with each other.

[0298] The partition wall 145 only needs to be insulating and can be formed using an inorganic material or an organic material. This is the case. Examples of the inorganic material include silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, aluminum oxide, aluminum nitride, and the like. Examples of the organic material include photosensitive resin materials such as acrylic resin or polyimide resin. Note that the silicon oxynitride film refers to a film having a higher oxygen content than nitrogen in its composition, preferably a film containing oxygen in the range of 55 atomic% or more and 65 atomic% or less, nitrogen in the range of 1 atomic% or more and 20 atomic% or less, silicon in the range of 25 atomic% or more and 35 atomic% or less, and hydrogen in the range of 0.1 atomic% or more and 10 atomic% or less. The silicon nitride oxide film refers to a film having a higher nitrogen content than oxygen in its composition, preferably a film containing nitrogen in the range of 55 atomic% or more and 65 atomic% or less, oxygen in the range of 1 atomic% or more and 20 atomic% or less, silicon in the range of 25 atomic% or more and 35 atomic% or less, and hydrogen in the range of 0.1 atomic% or more and 10 atomic% or less. In addition, the light-emitting layer 123R, the light-emitting layer 123G, and the light-emitting layer 123B preferably have light-emitting materials having functions of emitting different colors. For example, by having a light-emitting material having a function of emitting red in the light-emitting layer 123R, the region 221R exhibits red light emission, and by having a light-emitting material having a function of emitting green in the light-emitting layer 123G, the region 221G exhibits green light emission, and by having a light-emitting material having a function of emitting blue in the light-emitting layer 123B, the region 221B exhibits blue light emission. By using the light-emitting element 260a or the light-emitting element 260b having such a configuration for the pixel of the display device, a display device capable of full-color display can be manufactured. Also, the film thicknesses of the respective light-emitting layers may be the same or different.

[0299] Note that the silicon oxynitride film refers to a film having a higher oxygen content than nitrogen in its composition, preferably a film containing oxygen in the range of 55 atomic% or more and 65 atomic% or less, nitrogen in the range of 1 atomic% or more and 20 atomic% or less, silicon in the range of 25 atomic% or more and 35 atomic% or less, and hydrogen in the range of 0.1 atomic% or more and 10 atomic% or less. That is, it refers to a film containing oxygen in the range of 55 atomic% or more and 65 atomic% or less, nitrogen in the range of 1 atomic% or more and 20 atomic% or less, silicon in the range of 25 atomic% or more and 35 atomic% or less, and hydrogen in the range of 0.1 atomic% or more and 10 atomic% or less. The silicon nitride oxide film refers to a film having a higher nitrogen content than oxygen in its composition, preferably a film containing nitrogen in the range of 55 atomic% or more and 65 atomic% or less, oxygen in the range of 1 atomic% or more and 20 atomic% or less, silicon in the range of 25 atomic% or more and 35 atomic% or less, and hydrogen in the range of 0.1 atomic% or more and 10 atomic% or less. That is, it refers to a film containing nitrogen in the range of 55 atomic% or more and 65 atomic% or less, oxygen in the range of 1 atomic% or more and 20 atomic% or less, silicon in the range of 25 atomic% or more and 35 atomic% or less, and hydrogen in the range of 0.1 atomic% or more and 10 atomic% or less. Note that the silicon oxynitride film refers to a film having a higher oxygen content than nitrogen in its composition, preferably a film containing oxygen in the range of 55 atomic% or more and 65 atomic% or less, nitrogen in the range of 1 atomic% or more and 20 atomic% or less, silicon in the range of 25 atomic% or more and 35 atomic% or less, and hydrogen in the range of 0.1 atomic% or more and 10 atomic% or less. The silicon nitride oxide film refers to a film having a higher nitrogen content than oxygen in its composition, preferably a film containing nitrogen in the range of 55 atomic% or more and 65 atomic% or less, oxygen in the range of 1 atomic% or more and 20 atomic% or less, silicon in the range of 25 atomic% or more and 35 atomic% or less, and hydrogen in the range of 0.1 atomic% or more and 10 atomic% or less. That is, it refers to a film having a higher nitrogen content than oxygen in its composition, preferably a film containing nitrogen in the range of 55 atomic% or more and 65 atomic% or less, oxygen in the range of 1 atomic% or more and 20 atomic% or less, silicon in the range of 25 atomic% or more and 35 atomic% or less, and hydrogen in the range of 0.1 atomic% or more and 10 atomic% or less. That is, it refers to a film containing nitrogen in the range of 55 atomic% or more and 65 atomic% or less, oxygen in the range of 1 atomic% or more and 20 atomic% or less, silicon in the range of 25 atomic% or more and 35 atomic% or less, and hydrogen in the range of 0.1 atomic% or more and 10 atomic% or less. That is, it refers to a film containing nitrogen in the range of 55 atomic% or more and 65 atomic% or less, oxygen in the range of 1 atomic% or more and 20 atomic% or less, silicon in the range of 25 atomic% or more and 35 atomic% or less, and hydrogen in the range of 0.1 atomic% or more and 10 atomic% or less.

[0300] In addition, the light-emitting layer 123R, the light-emitting layer 123G, and the light-emitting layer 123B preferably have light-emitting materials having functions of emitting different colors. For example, by having a light-emitting material having a function of emitting red in the light-emitting layer 123R, the region 221R exhibits red light emission, and by having a light-emitting material having a function of emitting green in the light-emitting layer 123G, the region 221G exhibits green light emission, and by having a light-emitting material having a function of emitting blue in the light-emitting layer 123B, the region 221B exhibits blue light emission. That is, by having a light-emitting material having a function of emitting red in the light-emitting layer 123R, the region 221R exhibits red light emission, and by having a light-emitting material having a function of emitting green in the light-emitting layer 123G, the region 221G exhibits green light emission, and by having a light-emitting material having a function of emitting blue in the light-emitting layer 123B, the region 221B exhibits blue light emission. That is, by having a light-emitting material having a function of emitting green in the light-emitting layer 123G, the region 221G exhibits green light emission, and by having a light-emitting material having a function of emitting blue in the light-emitting layer 123B, the region 221B exhibits blue light emission. That is, by having a light-emitting material having a function of emitting blue in the light-emitting layer 123B, the region 221B exhibits blue light emission. By using the light-emitting element 260a or the light-emitting element 260b having such a configuration for the pixel of the display device, a display device capable of full-color display can be manufactured. Also, the film thicknesses of the respective light-emitting layers may be the same or different. That is, they may be the same or different. That is, they may be the same or different.

[0301] Further, any one or a plurality of the light-emitting layers 123B, 123G, and 123R preferably have the same configuration as the light-emitting layer 130 shown in Embodiment 1. By doing so, a light-emitting device with good luminous efficiency can be fabricated.

[0302] Note that any one or a plurality of the light-emitting layers 123B, 123G, and 123R may have a configuration in which two or more layers are stacked.

[0303] As described above, at least one light-emitting layer has the configuration of the light-emitting layer shown in Embodiment 1 and Embodiment 2, and by using the light-emitting device 260a or 260b having the light-emitting layer for the pixel of the display device, a display device with high luminous efficiency can be fabricated. That is, a display device having the light-emitting device 260a or 260b can reduce power consumption.

[0304] Note that by providing an optical element (e.g., a color filter, a polarizing plate, an antireflection film, etc.) in the light extraction direction of the electrode for extracting light, the color purity of the light-emitting devices 260a and 260b can be improved. Therefore, the color purity of the display device having the light-emitting device 260a or 260b can be enhanced. Alternatively, the external light reflection of the light-emitting devices 260a and 260b can be reduced. Therefore, the contrast ratio of the display device having the light-emitting device 260a or 260b can be increased.

[0305] Note that regarding other configurations of the light-emitting devices 260a and 260b, It is sufficient to consider the configuration of the light-emitting element in Embodiment 1 and Embodiment 2.

[0306] <Configuration Example 2 of Light-Emitting Element> Next, a configuration example different from the light-emitting element shown in FIGS. 5(A) and 5(B) will be described with reference to FIGS. 6(A) and 6(B). using, the following description will be given.

[0307] FIGS. 6(A) and 6(B) are cross-sectional views showing a light-emitting element according to an aspect of the present invention. In FIGS. 6(A) )(B), portions having the same functions as the reference numerals shown in FIGS. 5(A) and 5(B) may have the same hatch pattern, and the reference numerals may be omitted. Also, portions having the same functions may be given the same reference numerals, and detailed descriptions thereof may be omitted.

[0308] FIGS. 6(A) and 6(B) are configuration examples of a light-emitting element having a light-emitting layer between a pair of electrodes. FIG. 6 (A) shows a top emission type light-emitting element 262a that emits light in a direction opposite to the substrate 200, and FIG. 6(B) shows a light-emitting element 262b that emits light towards the substrate 200 side, which is a bottom emission type light-emitting element. However, one aspect of the present invention is not limited to this, and a dual emission type in which light emitted by the light-emitting element is extracted to both above and below the substrate 200 on which the light-emitting element is formed may also be used. is not limited to this, and a dual emission type in which light emitted by the light-emitting element is extracted to both above and below the substrate 200 on which the light-emitting element is formed may also be used. is not limited to this, and a dual emission type in which light emitted by the light-emitting element is extracted to both above and below the substrate 200 on which the light-emitting element is formed may also be used.

[0309] The light-emitting element 262a and the light-emitting element 262b have an electrode 101, an electrode 102 , an electrode 103, and an electrode 104 on the substrate 200. Also, between the electrode 101 and the electrode 102, and between the electrode 102 and the electrode 103, and between the electrode 102 and the electrode 104, at least a light-emitting layer 170, a light-emitting layer 190, and a charge generation layer 115 are provided. Also, a hole injection layer 111 and , a positive hole transport layer 112, an electron transport layer 113, an electron injection layer 114, and a positive hole injection layer 116 , a positive hole transport layer 117, an electron transport layer 118, and an electron injection layer 119.

[0310] Further, the electrode 101 includes a conductive layer 101a and a conductive layer 101b in contact with the conductive layer 101a . Further, the electrode 103 includes a conductive layer 103a and a conductive layer 103b in contact with the conductive layer 103a. The electrode 104 includes a conductive layer 104a and a conductive layer 104b in contact with the conductive layer 104a.

[0311] The light-emitting element 262a shown in FIG. 6(A) and the light-emitting element 262b shown in FIG. 6(B) are separated by a partition wall 145 between a region 222B sandwiched between the electrode 101 and the electrode 102, a region 222G sandwiched between the electrode 102 and the electrode 103, and a region 222R sandwiched between the electrode 102 and the electrode 104. The partition wall 145 is insulating. The partition wall 145 covers the ends of the electrode 101, the electrode 103, and the electrode 104 and has an opening overlapping with the electrodes. By providing the partition wall 145, it becomes possible to separate the electrodes on the substrate 200 of each region into island shapes. Further, as the charge generation layer 115, a material in which an electron acceptor is added to a positive hole transporting material or a material in which an electron donor is added to an electron transporting material can be used. When the conductivity of the charge generation layer 115 is as high as that of a pair of electrodes, carriers generated by the charge generation layer 115 may flow into adjacent pixels and cause adjacent pixels to emit light. Therefore, it is necessary to suppress the unauthorized light emission of adjacent pixels.

[0312] In order to do so, it is preferable that the charge generation layer 115 be formed of a material having a lower conductivity than that of the pair of electrodes. Preferably.

[0313] Further, the light-emitting elements 262a and 262b each have a substrate 220 having optical elements 224B, optical elements 224G, and optical elements 224R in the direction in which the light emitted from the regions 222B, 222G, and regions 222R is extracted. The light emitted from each region is emitted outside the light-emitting element through each optical element. That is, the light emitted from the region 222B is emitted through the optical element 224B, the light emitted from the region 222G is emitted through the optical element 224G, and the light emitted from the region 222R is emitted through the optical element 224R. Emitted.

[0314] In addition, the optical elements 224B, 224G, and 224R have a function of selectively transmitting light presenting a specific color from the incident light. For example, the light emitted from the region 222B emitted through the optical element 224B becomes light presenting blue, and the light emitted from the region 222G emitted through the optical element 224G becomes light presenting green, and the light emitted from the region 222R emitted through the optical element 224R becomes light presenting red. 4G becomes light presenting green, and the light emitted from the region 222R emitted through the optical element 224R becomes light presenting red.

[0315] For the optical elements 224R, 224G, and 224B, for example, a colored layer ( also referred to as a color filter), a band-pass filter, a multilayer film filter, etc. can be applied. Also, a color conversion element can be applied to the optical element. The color conversion element is an optical element that converts incident light into light having a wavelength longer than that of the light. As the color conversion element, it is preferable that the element uses quantum dots. By using quantum dots, the color reproducibility of the display device is converted into light having a wavelength longer than the wavelength of the light. As the color conversion element, it is preferable that the element uses quantum dots. By using quantum dots, the color reproducibility of the display device is improved. can be enhanced.

[0316] In addition, one or more other optical elements may be provided on the optical element 224R, the optical element 224G, and the optical element 224B. Examples of the other optical elements include a circular polarizing plate and an antireflection film. When a circular polarizing plate is provided on the side from which the light emitted by the light-emitting element of the display device is extracted, it is possible to prevent the phenomenon that the light incident from the outside of the display device is reflected inside the display device and then emitted to the outside. When a circular polarizing plate is provided on the side from which the light emitted by the light-emitting element of the display device is extracted, it is possible to prevent the phenomenon that the light incident from the outside of the display device is reflected inside the display device and then emitted to the outside. When a circular polarizing plate is provided on the side from which the light emitted by the light-emitting element of the display device is extracted, it is possible to prevent the phenomenon that the light incident from the outside of the display device is reflected inside the display device and then emitted to the outside. When a circular polarizing plate is provided on the side from which the light emitted by the light-emitting element of the display device is extracted, it is possible to prevent the phenomenon that the light incident from the outside of the display device is reflected inside the display device and then emitted to the outside. In addition, when an antireflection film is provided, it is possible to weaken the external light reflected on the surface of the display device. As a result, the light emitted by the display device can be clearly observed.

[0317] In FIGS. 6(A) and 6(B), the light emitted from each region through each optical element is schematically illustrated by dashed arrows as light presenting blue (B), light presenting green (G), and light presenting red (R), respectively. In FIGS. 6(A) and 6(B), the light emitted from each region through each optical element is schematically illustrated by dashed arrows as light presenting blue (B), light presenting green (G), and light presenting red (R), respectively. In FIGS. 6(A) and 6(B), the light emitted from each region through each optical element is schematically illustrated by dashed arrows as light presenting blue (B), light presenting green (G), and light presenting red (R), respectively.

[0318] In addition, a light-shielding layer 223 is provided between the optical elements. The light-shielding layer 223 has a function of shielding the light emitted from adjacent regions. Note that a configuration without the light-shielding layer 223 may also be employed. In addition, a light-shielding layer 223 is provided between the optical elements. The light-shielding layer 223 has a function of shielding the light emitted from adjacent regions. Note that a configuration without the light-shielding layer 223 may also be employed. In addition, a light-shielding layer 223 is provided between the optical elements. The light-shielding layer 223 has a function of shielding the light emitted from adjacent regions. Note that a configuration without the light-shielding layer 223 may also be employed.

[0319] The light-shielding layer 223 has a function of suppressing the reflection of external light. Or, the light-shielding layer 223 has a function of preventing color mixing of the light emitted from adjacent light-emitting elements. As the light-shielding layer 223, a metal, a resin containing a black pigment, carbon black, a metal oxide, a composite oxide containing a solid solution of a plurality of metal oxides, or the like can be used. The light-shielding layer 223 has a function of suppressing the reflection of external light. Or, the light-shielding layer 223 has a function of preventing color mixing of the light emitted from adjacent light-emitting elements. As the light-shielding layer 223, a metal, a resin containing a black pigment, carbon black, a metal oxide, a composite oxide containing a solid solution of a plurality of metal oxides, or the like can be used. The light-shielding layer 223 has a function of suppressing the reflection of external light. Or, the light-shielding layer 223 has a function of preventing color mixing of the light emitted from adjacent light-emitting elements. As the light-shielding layer 223, a metal, a resin containing a black pigment, carbon black, a metal oxide, a composite oxide containing a solid solution of a plurality of metal oxides, or the like can be used. The light-shielding layer 223 has a function of suppressing the reflection of external light. Or, the light-shielding layer 223 has a function of preventing color mixing of the light emitted from adjacent light-emitting elements. As the light-shielding layer 223, a metal, a resin containing a black pigment, carbon black, a metal oxide, a composite oxide containing a solid solution of a plurality of metal oxides, or the like can be used.

[0320] Note that the optical element 224B and the optical element 224G overlap with the light-shielding layer 223 in the region where... They may have overlapping regions with each other. Alternatively, the optical element 224G and the optical element 224R may have overlapping regions with each other in the region overlapping with the light-shielding layer 223. Alternatively, the optical element 224R and the optical element 224B may have overlapping regions with each other in the region overlapping with the light-shielding layer 223.

[0321] In addition, as the configuration of the substrate 200 and the substrate 220 having the optical element, the first embodiment may be referred to.

[0322] Furthermore, the light-emitting element 262a and the light-emitting element 262b have a microcavity structure. .

[0323] ≪Microcavity Structure≫ The light emitted from the light-emitting layer 170 and the light-emitting layer 190 is resonated between a pair of electrodes (for example, the electrode 10 1 and the electrode 102). In addition, the light-emitting layer 170 and the light-emitting layer 190 are formed at positions where the light of a desired wavelength among the emitted light is enhanced. For example, by adjusting the optical distance from the reflection region of the electrode 101 to the light-emitting region of the light-emitting layer 170 and the optical distance from the reflection region of the electrode 102 to the light-emitting region of the light-emitting layer 170, the light of the desired wavelength among the light emitted from the light-emitting layer 170 can be enhanced. Also, by adjusting the optical distance from the reflection region of the electrode 101 to the light-emitting region of the light-emitting layer 190 and the optical distance from the reflection region of the electrode 102 to the light-emitting region of the light-emitting layer 190, the light of the desired wavelength among the light emitted from the light-emitting layer 190 can be enhanced. That is, in the case of a light-emitting element in which a plurality of light-emitting layers (here, the light-emitting layer 170 and the light-emitting layer 190) are stacked, it is preferable to optimize the optical distance of each of the light-emitting layer 170 and the light-emitting layer 190. optical distance and the optical distance from the reflection region of the electrode 102 to the light-emitting region of the light-emitting layer 190, the light of the desired wavelength among the light emitted from the light-emitting layer 190 can be enhanced. That is, in the case of a light-emitting element in which a plurality of light-emitting layers (here, the light-emitting layer 170 and the light-emitting layer 190) are stacked, it is preferable to optimize the optical distance of each of the light-emitting layer 170 and the light-emitting layer 190. distance is preferably optimized.

[0324] Further, in the light-emitting element 262a and the light-emitting element 262b, by adjusting the thickness of the conductive layer (conductive layer 1 01b, conductive layer 103b, and conductive layer 104b) in each region, it is possible to enhance light of a desired wavelength among the light emitted from the light-emitting layer 170 and the light-emitting layer 190. Note that, by making at least one of the hole injection layer 111 and the hole transport layer 112 have different thicknesses in each region, it is also possible to enhance the light emitted from the light-emitting layer 170 and the light-emitting layer 190.

[0325] For example, in the electrodes 101 to 104, when the refractive index of the conductive material having a function of reflecting light is smaller than the refractive index of the light-emitting layer 170 or the light-emitting layer 190, the film thickness of the conductive layer 101b included in the electrode 101 is adjusted so that the optical distance between the electrode 101 and the electrode 102 is m B λ B / 2 (m B is a natural number, λ B is the wavelength of the light to be enhanced in the region 222B, respectively). Similarly, the film thickness of the conductive layer 103b included in the electrode 103 is adjusted so that the optical distance between the electrode 103 and the electrode 102 is m G λ G / 2 (m G is a natural number, λ G is the wavelength of the light to be enhanced in the region 222G respectively). Further, the film thickness of the conductive layer 104b included in the electrode 104 is adjusted so that the optical distance between the electrode 104 and the electrode 102 is m R λ R / 2 (m R is a natural number, λ R is the wavelength of the light to be enhanced in the region 222R, respectively).

[0326] ​In addition, when it is difficult to precisely determine the reflection regions of electrodes 101 to 104, an optical distance for enhancing the light emitted from the light-emitting layer 170 or the light-emitting layer 190 may be derived by assuming an arbitrary region of electrodes 101 to 104 as the reflection region. Also, when it is difficult to precisely determine the light-emitting regions of the light-emitting layer 170 and the light-emitting layer 190, an optical distance for enhancing the light emitted from the light-emitting layer 170 and the light-emitting layer 190 may be derived by assuming an arbitrary region of the light-emitting layer 170 and the light-emitting layer 190 as the light-emitting region. By assuming an arbitrary region of electrodes 101 to 104 as the reflection region, an optical distance for enhancing the light emitted from the light-emitting layer 170 or the light-emitting layer 190 may be derived. In addition, when it is difficult to precisely determine the light-emitting regions of the light-emitting layer 170 and the light-emitting layer 190, an optical distance for enhancing the light...

Claims

1. A light-emitting device having a light-emitting layer between a pair of electrodes, wherein the light-emitting layer includes a first organic compound, a second organic compound, and a phosphorescent material, the first organic compound is a heterocyclic compound having at least one of a triazine skeleton, a pyrazine skeleton, a pyridazine skeleton, or a pyridine skeleton, the second organic compound is a compound having a pyrrole skeleton, the first organic compound and the second organic compound form a combination that forms an exciplex, the peak of the emission spectrum of the mixed thin film of the first organic compound and the second organic compound is at a longer wavelength than each of the peak of the emission spectrum of the thin film of the first organic compound and the peak of the emission spectrum of the thin film of the second organic compound, the LUMO level of the first organic compound is lower than the LUMO level of the second organic compound, the HOMO level of the first organic compound is lower than the HOMO level of the second organic compound, the LUMO level of the phosphorescent material is higher than the LUMO level of the first organic compound, the HOMO level of the phosphorescent material is higher than the HOMO level of the second organic compound, the energy difference between the HOMO level of the phosphorescent material and the HOMO level of the second organic compound is 0.05 eV or more and 0.4 eV or less, a light-emitting device in which the energy difference between the LUMO level and the HOMO level of the phosphorescent material is larger than the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound.

2. A light-emitting device having a light-emitting layer between a pair of electrodes, wherein the light-emitting layer includes a first organic compound, a second organic compound, and a phosphorescent material, the first organic compound is a heterocyclic compound having at least one of a triazine skeleton, a pyrazine skeleton, a pyridazine skeleton, or a pyridine skeleton, the second organic compound is a compound having a pyrrole skeleton, the first organic compound and the second organic compound form a combination that forms an exciplex, the peak of the emission spectrum of the mixed thin film of the first organic compound and the second organic compound is at a longer wavelength than each of the peak of the emission spectrum of the thin film of the first organic compound and the peak of the emission spectrum of the thin film of the second organic compound, the LUMO level of the first organic compound is lower than the LUMO level of the second organic compound, The HOMO level of the first organic compound is lower than the HOMO level of the second organic compound, the LUMO level of the phosphorescent material is higher than the LUMO level of the first organic compound, the energy difference between the LUMO level of the phosphorescent material and the LUMO level of the first organic compound is 0.05 eV or more, the HOMO level of the phosphorescent material is higher than the HOMO level of the second organic compound, the energy difference between the HOMO level of the phosphorescent material and the HOMO level of the second organic compound is 0.05 eV or more and 0.4 eV or less, a light-emitting device in which the energy difference between the LUMO level and the HOMO level of the phosphorescent material is larger than the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound.

3. A light-emitting device having a light-emitting layer between a pair of electrodes, wherein the light-emitting layer contains a first organic compound, a second organic compound, and a phosphorescent material, the first organic compound is a heterocyclic compound having at least one of a triazine skeleton, a pyrazine skeleton, a pyridazine skeleton, or a pyridine skeleton, the second organic compound is a compound having a pyrrole skeleton, the first organic compound and the second organic compound are a combination that forms an exciplex, the peak of the emission spectrum of the mixed thin film of the first organic compound and the second organic compound has a longer wavelength than the peak of the emission spectrum of the thin film of the first organic compound and the peak of the emission spectrum of the thin film of the second organic compound, respectively, the LUMO level of the first organic compound is lower than the LUMO level of the second organic compound, the HOMO level of the first organic compound is lower than the HOMO level of the second organic compound, the LUMO level of the phosphorescent material is higher than the LUMO level of the first organic compound, the energy difference between the LUMO level of the phosphorescent material and the LUMO level of the first organic compound is 0.1 eV or more, the HOMO level of the phosphorescent material is higher than the HOMO level of the second organic compound, the energy difference between the HOMO level of the phosphorescent material and the HOMO level of the second organic compound is 0.05 eV or more and 0.4 eV or less, a light-emitting device in which the energy difference between the LUMO level and the HOMO level of the phosphorescent material is larger than the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound.

4. A light-emitting device having a light-emitting layer between a pair of electrodes, wherein the light-emitting layer includes a first organic compound, a second organic compound, and a phosphorescent material, the first organic compound is a heterocyclic compound having at least one of a triazine skeleton, a pyrazine skeleton, a pyridazine skeleton, or a pyridine skeleton, the second organic compound is a compound having a pyrrole skeleton, the first organic compound and the second organic compound are a combination that forms an exciplex, the peak of the emission spectrum of the mixed thin film of the first organic compound and the second organic compound is at a longer wavelength than the peak of the emission spectrum of the thin film of the first organic compound and the peak of the emission spectrum of the thin film of the second organic compound, respectively, the LUMO level of the first organic compound is lower than the LUMO level of the second organic compound, the HOMO level of the first organic compound is lower than the HOMO level of the second organic compound, the LUMO level of the phosphorescent material is higher than the LUMO level of the first organic compound, the energy difference between the LUMO level of the phosphorescent material and the LUMO level of the first organic compound is 0.2 eV or more, the HOMO level of the phosphorescent material is higher than the HOMO level of the second organic compound, the energy difference between the HOMO level of the phosphorescent material and the HOMO level of the second organic compound is 0.05 eV or more and 0.4 eV or less, the energy difference between the LUMO level and the HOMO level of the phosphorescent material is greater than the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound, the light-emitting device.

5. A light-emitting device having a light-emitting layer between a pair of electrodes, wherein the light-emitting layer includes a first organic compound, a second organic compound, and a phosphorescent material, the first organic compound is a heterocyclic compound having at least one of a triazine skeleton, a pyrazine skeleton, or a pyridazine skeleton, the second organic compound is a compound having a pyrrole skeleton, the first organic compound and the second organic compound are a combination that forms an exciplex, the peak of the emission spectrum of the mixed thin film of the first organic compound and the second organic compound is at a longer wavelength than the peak of the emission spectrum of the thin film of the first organic compound and the peak of the emission spectrum of the thin film of the second organic compound, respectively, The LUMO level of the first organic compound is lower than the LUMO level of the second organic compound, The HOMO level of the first organic compound is lower than the HOMO level of the second organic compound, The LUMO level of the phosphorescent material is higher than the LUMO level of the first organic compound, The HOMO level of the phosphorescent material is higher than the HOMO level of the second organic compound, The energy difference between the HOMO level of the phosphorescent material and the HOMO level of the second organic compound is 0.05 eV or more and 0.4 eV or less, The energy difference between the LUMO level and the HOMO level of the phosphorescent material is larger than the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound, a light-emitting device.

6. A light-emitting device having a light-emitting layer between a pair of electrodes, The light-emitting layer includes a first organic compound, a second organic compound, and a phosphorescent material, The first organic compound is a heterocyclic compound having at least one of a triazine skeleton, a pyrazine skeleton, or a pyridazine skeleton, The second organic compound is a compound having a pyrrole skeleton, The first organic compound and the second organic compound are a combination that forms an exciplex, The peak of the emission spectrum of the mixed thin film of the first organic compound and the second organic compound is at a longer wavelength than each of the peak of the emission spectrum of the thin film of the first organic compound and the peak of the emission spectrum of the thin film of the second organic compound, The LUMO level of the first organic compound is lower than the LUMO level of the second organic compound, The HOMO level of the first organic compound is lower than the HOMO level of the second organic compound, The LUMO level of the phosphorescent material is higher than the LUMO level of the first organic compound, The energy difference between the LUMO level of the phosphorescent material and the LUMO level of the first organic compound is 0.05 eV or more, The HOMO level of the phosphorescent material is higher than the HOMO level of the second organic compound, The energy difference between the HOMO level of the phosphorescent material and the HOMO level of the second organic compound is 0.05 eV or more and 0.4 eV or less, The energy difference between the LUMO level and the HOMO level of the phosphorescent material is larger than the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound, a light-emitting device.

7. A light-emitting device having a light-emitting layer between a pair of electrodes, The light-emitting layer has a first organic compound, a second organic compound, and a phosphorescent material. The first organic compound is a heterocyclic compound having at least one of a triazine skeleton, a pyrazine skeleton, or a pyridazine skeleton. The second organic compound is a compound having a pyrrole skeleton. The first organic compound and the second organic compound are a combination that forms an exciplex. The peak of the emission spectrum of the mixed thin film of the first organic compound and the second organic compound has a longer wavelength than the peak of the emission spectrum of the thin film of the first organic compound and the peak of the emission spectrum of the thin film of the second organic compound, respectively. The LUMO level of the first organic compound is lower than the LUMO level of the second organic compound. The HOMO level of the first organic compound is lower than the HOMO level of the second organic compound. The LUMO level of the phosphorescent material is higher than the LUMO level of the first organic compound. The energy difference between the LUMO level of the phosphorescent material and the LUMO level of the first organic compound is 0.1 eV or more. The HOMO level of the phosphorescent material is higher than the HOMO level of the second organic compound. The energy difference between the HOMO level of the phosphorescent material and the HOMO level of the second organic compound is 0.05 eV or more and 0.4 eV or less. The energy difference between the LUMO level and the HOMO level of the phosphorescent material is larger than the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound, a light-emitting device.

8. A light-emitting device having a light-emitting layer between a pair of electrodes, The light-emitting layer has a first organic compound, a second organic compound, and a phosphorescent material. The first organic compound is a heterocyclic compound having at least one of a triazine skeleton, a pyrazine skeleton, or a pyridazine skeleton. The second organic compound is a compound having a pyrrole skeleton. The first organic compound and the second organic compound are a combination that forms an exciplex. The peak of the emission spectrum of the mixed thin film of the first organic compound and the second organic compound has a longer wavelength than the peak of the emission spectrum of the thin film of the first organic compound and the peak of the emission spectrum of the thin film of the second organic compound, respectively. The LUMO level of the first organic compound is lower than the LUMO level of the second organic compound. The HOMO level of the first organic compound is lower than the HOMO level of the second organic compound, the LUMO level of the phosphorescent material is higher than the LUMO level of the first organic compound, the energy difference between the LUMO level of the phosphorescent material and the LUMO level of the first organic compound is 0.2 eV or more, the HOMO level of the phosphorescent material is higher than the HOMO level of the second organic compound, the energy difference between the HOMO level of the phosphorescent material and the HOMO level of the second organic compound is 0.05 eV or more and 0.4 eV or less, the energy difference between the LUMO level and the HOMO level of the phosphorescent material is larger than the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound, a light-emitting device.

9. A light-emitting device having a light-emitting layer between a pair of electrodes, wherein the light-emitting layer includes a first organic compound, a second organic compound, and a phosphorescent material, the first organic compound is a heterocyclic compound having a triazine skeleton, the second organic compound is a compound having a pyrrole skeleton, the first organic compound and the second organic compound are a combination that forms an exciplex, the peak of the emission spectrum of the mixed thin film of the first organic compound and the second organic compound has a longer wavelength than the peak of the emission spectrum of the thin film of the first organic compound and the peak of the emission spectrum of the thin film of the second organic compound, respectively, the LUMO level of the first organic compound is lower than the LUMO level of the second organic compound, the HOMO level of the first organic compound is lower than the HOMO level of the second organic compound, the LUMO level of the phosphorescent material is higher than the LUMO level of the first organic compound, the HOMO level of the phosphorescent material is higher than the HOMO level of the second organic compound, the energy difference between the HOMO level of the phosphorescent material and the HOMO level of the second organic compound is 0.05 eV or more and 0.4 eV or less, the energy difference between the LUMO level and the HOMO level of the phosphorescent material is larger than the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound, a light-emitting device.

10. A light-emitting device having a light-emitting layer between a pair of electrodes, wherein the light-emitting layer includes a first organic compound, a second organic compound, and a phosphorescent material, The first organic compound is a heterocyclic compound having a triazine skeleton, The second organic compound is a compound having a pyrrole skeleton, The first organic compound and the second organic compound are a combination that forms an exciplex, The peak of the emission spectrum of the mixed thin film of the first organic compound and the second organic compound is at a longer wavelength than each of the peak of the emission spectrum of the thin film of the first organic compound and the peak of the emission spectrum of the thin film of the second organic compound, The LUMO level of the first organic compound is lower than the LUMO level of the second organic compound, The HOMO level of the first organic compound is lower than the HOMO level of the second organic compound, The LUMO level of the phosphorescent material is higher than the LUMO level of the first organic compound, The energy difference between the LUMO level of the phosphorescent material and the LUMO level of the first organic compound is 0.05 eV or more, The HOMO level of the phosphorescent material is higher than the HOMO level of the second organic compound, The energy difference between the HOMO level of the phosphorescent material and the HOMO level of the second organic compound is 0.05 eV or more and 0.4 eV or less, An emission element in which the energy difference between the LUMO level and the HOMO level of the phosphorescent material is larger than the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound. Claim 11 An emission element having an emission layer between a pair of electrodes, The emission layer contains a first organic compound, a second organic compound, and a phosphorescent material, The first organic compound is a heterocyclic compound having a triazine skeleton, The second organic compound is a compound having a pyrrole skeleton, The first organic compound and the second organic compound are a combination that forms an exciplex, The peak of the emission spectrum of the mixed thin film of the first organic compound and the second organic compound is at a longer wavelength than each of the peak of the emission spectrum of the thin film of the first organic compound and the peak of the emission spectrum of the thin film of the second organic compound, The LUMO level of the first organic compound is lower than the LUMO level of the second organic compound, The HOMO level of the first organic compound is lower than the HOMO level of the second organic compound, The LUMO level of the phosphorescent material is higher than the LUMO level of the first organic compound, The energy difference between the LUMO level of the phosphorescent material and the LUMO level of the first organic compound is 0.1 eV or more, the HOMO level of the phosphorescent material is higher than the HOMO level of the second organic compound, the energy difference between the HOMO level of the phosphorescent material and the HOMO level of the second organic compound is 0.05 eV or more and 0.4 eV or less, a light-emitting device in which the energy difference between the LUMO level and the HOMO level of the phosphorescent material is larger than the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound.

12. A light-emitting device having a light-emitting layer between a pair of electrodes, wherein the light-emitting layer includes a first organic compound, a second organic compound, and a phosphorescent material, the first organic compound is a heterocyclic compound having a triazine skeleton, the second organic compound is a compound having a pyrrole skeleton, the first organic compound and the second organic compound are a combination that forms an exciplex, the peak of the emission spectrum of the mixed thin film of the first organic compound and the second organic compound has a longer wavelength than the peak of the emission spectrum of the thin film of the first organic compound and the peak of the emission spectrum of the thin film of the second organic compound, the LUMO level of the first organic compound is lower than the LUMO level of the second organic compound, the HOMO level of the first organic compound is lower than the HOMO level of the second organic compound, the LUMO level of the phosphorescent material is higher than the LUMO level of the first organic compound, the energy difference between the LUMO level of the phosphorescent material and the LUMO level of the first organic compound is 0.2 eV or more, the HOMO level of the phosphorescent material is higher than the HOMO level of the second organic compound, the energy difference between the HOMO level of the phosphorescent material and the HOMO level of the second organic compound is 0.05 eV or more and 0.4 eV or less, a light-emitting device in which the energy difference between the LUMO level and the HOMO level of the phosphorescent material is larger than the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound.

13. In any one of Claims 1 to 12, The T level of the first organic compound １ and the T level of the second organic compound １ are each higher than the T level of the phosphorescent material, １ a light-emitting element.

14. a light-emitting device according to any one of Claims 1 to 13, and at least one of a color filter or a transistor, a display device having the same.

15. The display device according to claim 14, at least one of a housing or a touch sensor, An electronic device having the same.

16. The light-emitting element according to any one of claims 1 to 13, at least one of a housing or a touch sensor, A lighting device having the same.

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