Light-emitting element, display device, electronic appliance, and illumination device

Abstract

To provide a light-emitting element with high luminous efficiency.SOLUTION: A light-emitting element includes first to third organic compounds. The first organic compound has a function of converting triplet excited energy into light emission. The second organic compound has a benzofuropyrimidine skeleton or a benzothienopyrimidine skeleton. The third organic compound is a fluorescence compound. The light emitted from the light-emitting element is light emission exhibited from the first organic compound or the third organic compound to which the excitation energy is supplied from an exciplex formed by the first organic compound and the second organic compound.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 or the like relates to an article, a method, or a manufacturing method. Alternatively, 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, their driving methods, or their manufacturing methods.

[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 or the like relates to an article, a method, or a manufacturing method. Alternatively, 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, their driving methods, or their manufacturing methods. 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 or the like relates to an article, a method, or a manufacturing method. Alternatively, 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, their driving methods, or their manufacturing methods. 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 or the like relates to an article, a method, or a manufacturing method. Alternatively, 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, their driving methods, or their manufacturing methods. 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 or the like relates to an article, a method, or a manufacturing method. Alternatively, 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, their driving methods, or their manufacturing methods. 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 or the like relates to an article, a method, or a manufacturing method. Alternatively, 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, their driving methods, or their manufacturing methods. 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 or the like relates to an article, a method, or a manufacturing method. Alternatively, 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, their driving methods, or their manufacturing methods. 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 or the like relates to an article, a method, or a manufacturing method. Alternatively, 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, their driving methods, or their manufacturing methods.

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 substance is sandwiched between a pair of electrodes. By applying a voltage between the electrodes of this element, light emission from the light-emitting substance can be obtained. 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 substance is sandwiched between a pair of electrodes. By applying a voltage between the electrodes of this element, light emission from the light-emitting substance can be obtained. 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 substance is sandwiched between a pair of electrodes. By applying a voltage between the electrodes of this element, light emission from the light-emitting substance can be obtained. 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 substance is sandwiched between a pair of electrodes. By applying a voltage between the electrodes of this element, light emission from the light-emitting substance can be obtained.

[0004] Since the above-described light-emitting element is self-luminous, a display device using this element has advantages such as excellent visibility, no need for a backlight, low power consumption, and the like. 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 self-luminous, a display device using this element has advantages such as excellent visibility, no need for a backlight, low power consumption, and the like. 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 self-luminous, a display device using this element has advantages such as excellent visibility, no need for a backlight, low power consumption, and the like. 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 compound is used as the light-emitting substance, and an EL layer containing the light-emitting organic compound is sandwiched between a pair of electrodes. In the case of a light-emitting element (e.g., an organic EL element) provided with layers, when a voltage is applied between a pair of electrodes, electrons are injected from the cathode and holes are injected from the anode into the light-emitting EL layer respectively, and a current flows. Then, the injected electrons and holes recombine, causing the light-emitting organic compound to enter an excited state, and light can be obtained from the excited light-emitting organic compound.

[0006] As the types of excited states formed by organic compounds, there are singlet excited states (S * ) and triplet excited states (T * ). Light emission from singlet excited states is called fluorescence, and light emission from triplet excited states is called phosphorescence. Also, their statistical generation ratios in the light-emitting element are S :T * = * = 1:3. Therefore, a light-emitting element using a compound that emits phosphorescence (phosphorescent compound) can obtain higher luminous efficiency than a light-emitting element using a compound that emits fluorescence (fluorescent compound). Thus, in recent years, the development of light-emitting elements using phosphorescent compounds capable of converting the energy of triplet excited states into light emission has been actively carried out. Among light-emitting elements using phosphorescent compounds, especially in light-emitting elements that exhibit blue light emission, it is difficult to develop stable compounds having a high triplet excitation energy level, and thus they have not yet reached practical use. Therefore, the development of light-emitting elements using more stable fluorescent compounds has been carried out, and methods for increasing the luminous efficiency of light-emitting elements using fluorescent compounds (fluorescent light-emitting elements) have been explored.

[0007] As an example, thermally activated delayed fluorescence (Thermally Activated Del

[0008] As an example, thermally activated delayed fluorescence (Thermally Activated Del ​​​​​There are known light-emitting devices using thermally activated delayed fluorescence (TADF) materials. . In thermally activated delayed fluorescence materials, singlet excited states are generated from triplet excited states by reverse intersystem crossing, and are converted to light emission from the singlet excited states.

[0009] In addition, in a light-emitting device having a thermally activated delayed fluorescence material and a fluorescent compound, a method has been proposed in which the singlet excitation energy of the thermally activated delayed fluorescence material is transferred to the fluorescent compound, and light emission is obtained from the fluorescent compound (see Patent Document 1). [Prior Art Documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2014-45179 [Non-Patent Documents]

[0011] [Non-Patent Document 1] T. Sajoto et al., J. Am. Chem. Soc., 2009, 131, 9813 [Summary of the Invention] [Problems to be Solved by the Invention]

[0012] In order to increase the luminous efficiency of a fluorescent light-emitting device, it is preferable that singlet excited states are efficiently generated from triplet excited states and that the energy transfer efficiency to the fluorescent light-emitting material is high. Therefore, there is a demand for the development of techniques and materials for efficiently generating singlet excited states from triplet excited states and further improving the luminous efficiency of light-emitting devices. In addition, for the materials used in the light-emitting layer, materials with good carrier transport properties are required in order to reduce the driving voltage.

[0013] Therefore, in one aspect of the present invention, an object is to provide a light-emitting element with high luminous efficiency. Or, in one aspect of the present invention, an object is to provide a light-emitting element with a low driving voltage. Or, in one aspect of the present invention, an object is to provide a light-emitting element with good reliability. Or, in one aspect of the present invention, an object is to provide a light-emitting element with reduced power consumption. Or, in one aspect of the present invention, an object is to provide a novel light-emitting element. Or In one aspect of the present invention, an object is to provide a novel light-emitting device. Or, in one aspect of the present invention an object is to provide a novel electronic device.

[0014] 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 than the above are obvious from the description in the specification and the like, and it is possible to extract problems other than the above from the description in the specification and the like.

Means for Solving the Problems

[0015] As described above, in a light-emitting element that exhibits fluorescence, development of a technique for efficiently converting triplet excitation energy into light emission is required. Therefore, it is required to increase the energy transfer efficiency between the materials used in the light-emitting layer.

[0016] Therefore, one aspect of the present invention has a light-emitting layer between a pair of electrodes, and the light-emitting layer has a first organic compound, a second organic compound, and a third organic compound. The first organic compound has a function of converting triplet excitation energy into light emission. The second organic compound has a benzofuropyrimidine skeleton or a benzothienopyrimidine skeleton, and the third organic compound has singlet excitation energy It has a function of converting energy into light, and the light emitted by the light-emitting layer includes the light emitted by the third organic compound. It is a light-emitting device.

[0017] In the above configuration, it is preferable that the first organic compound has a function of donating excitation energy to the third organic compound.

[0018] Another aspect of the present invention is 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 third organic compound. The first organic compound and the second organic compound can form an exciplex. The first organic compound has a function of converting triplet excitation energy into light. The second organic compound has a benzofuropyrimidine skeleton or a benzothienopyrimidine skeleton. The third organic compound has a function of converting singlet excitation energy into light. The light emitted by the light-emitting layer includes the light emitted by the third organic compound. It is a light-emitting device.

[0019] In the above configuration, it is preferable that the exciplex has a function of donating excitation energy to the third organic compound.

[0020] In the above configuration, it is preferable that the benzofuropyrimidine skeleton is a benzofuro[3,2-d]pyrimidine skeleton, and the benzothienopyrimidine skeleton is a benzothieno[3,2-d]pyrimidine skeleton.

[0021] In the above configuration, it is preferable that the benzofuro[3,2-d]pyrimidine skeleton or the benzothieno[3,2-d]pyrimidine skeleton has a substituent at the 4-position or the 8-position.

[0022] In the above configuration, the first organic compound is Ru, Rh, Pd, Os, Ir, or​​​​​​​​​​ Preferably, it has Pt.

[0023] Further, in the above configuration, the first organic compound preferably exhibits phosphorescence.

[0024] Further, in the above configuration, 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 third organic compound. Preferably, it has a region overlapping with the absorption band on the longest wavelength side of the absorption spectrum of the third organic compound.

[0025] Further, in the above configuration, the first organic compound preferably has a luminescence quantum yield of 0% or more and 40% or less at room temperature. Preferably, it has a luminescence quantum yield of 0% or more and 40% or less at room temperature.

[0026] Further, in the above configuration, the exciplex preferably has a function of exhibiting luminescence having a luminescence efficiency higher than the luminescence efficiency of the luminescence exhibited by the first organic compound. Preferably, it has a function of exhibiting luminescence having a luminescence efficiency higher than the luminescence efficiency of the luminescence exhibited by the first organic compound.

[0027] Further, in the above configuration, the third organic compound preferably exhibits fluorescence.

[0028] Further, in the above configuration, the energy difference between the singlet excitation energy and the triplet excitation energy of the first organic compound is preferably 0 eV or more and 0.2 eV or less. Preferably, the energy difference between the singlet excitation energy and the triplet excitation energy of the first organic compound is 0 eV or more and 0.2 eV or less.

[0029] Another aspect of the present invention is a display device having the light-emitting element of 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 having the display device and at least one of a housing or a touch sensor. Another aspect of the present invention is a display device having the light-emitting element of 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 having the display device and at least one of a housing or a touch sensor. Preferably, it has a display device having the light-emitting element of 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 having the display device and at least one of a housing or a touch sensor. Further, another aspect of the present invention is a lighting device having the light-emitting element of each of the above configurations and at least one of a housing or a touch sensor. 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, in this specification Preferably, it has a lighting device having the light-emitting element of each of the above configurations and at least one of a housing or a touch sensor. 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, in this specification Preferably, it has a lighting device having the light-emitting element of each of the above configurations and at least one of a housing or a touch sensor. 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, in this specification The light-emitting device referred to herein means an image display device or a light source (including a lighting device). Also, a display module in which a connector, for example, an FPC (Flexible Printed Circuit), a TCP (Tape Carrier Package) is attached to the light-emitting element, a display module in which a printed wiring board is provided at the tip of the TCP, or a display module in which an IC (integrated circuit) is directly mounted by the COG (Chip On Glass) method may be included in the light-emitting device. A connector, for example, an FPC (Flexible Printed Circuit), a TCP (Tape Carrier Package) is attached to the light-emitting element. A display module in which a connector, for example, an FPC (Flexible Printed Circuit), a TCP (Tape Carrier Package) is attached to the light-emitting element. A display module in which a printed wiring board is provided at the tip of the TCP, or a display module in which an IC (integrated circuit) is directly mounted by the COG (Chip On Glass) method may be included in the light-emitting device. A display module in which an IC (integrated circuit) is directly mounted by the COG (Chip On Glass) method. A display module in which an IC (integrated circuit) is directly mounted by the COG (Chip On Glass) method may be included in the light-emitting device.

Advantages of the Invention

[0030] According to one aspect of the present invention, a light-emitting element with high luminous efficiency can be provided. Or, according to one aspect of the present invention, a light-emitting element with a low driving voltage can be provided. Or, according to one aspect of the present invention, a light-emitting element with good reliability can be provided. Or, according to one aspect of the present invention, a light-emitting element with reduced power consumption can be provided. Or, according to one aspect of the present invention, a novel light-emitting element can be provided. Or, according to one aspect of the present invention, a novel light-emitting device can be provided. Or, according to one aspect of the present invention, a novel electronic device can be provided. According to one aspect of the present invention, a light-emitting element with a low driving voltage can be provided. According to one aspect of the present invention, a light-emitting element with good reliability can be provided. According to one aspect of the present invention, a light-emitting element with reduced power consumption can be provided. According to one aspect of the present invention, a novel light-emitting element can be provided. According to one aspect of the present invention, a novel light-emitting device can be provided. According to one aspect of the present invention, a novel electronic device can be provided.

[0031] 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 to have all of these effects. Note that other effects are obvious from the descriptions in the specification, drawings, claims, etc., and it is possible to extract these other effects from the descriptions 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 descriptions in the specification, drawings, claims, etc., and it is possible to extract these other effects from the descriptions in the specification, drawings, claims, etc. Note that other effects are obvious from the descriptions in the specification, drawings, claims, etc., and it is possible to extract these other effects from the descriptions in the specification, drawings, claims, etc.

Brief Description of the Drawings

[0032]

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Mode for Carrying Out the Invention

[0033] 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 should not be construed as being limited to the description of the embodiments and examples shown below. It should be noted that the positions, sizes, ranges, etc. of each component shown in the drawings and the like may not represent the actual positions, sizes, ranges, etc. for the sake of easy understanding. For this reason, the disclosed invention is not necessarily limited to the positions, sizes, ranges, etc. disclosed in the drawings and the like.

[0034] In addition, in this specification and the like, ordinal numbers such as first, second, etc. are used for convenience, and do not have any ordinal meaning. and do not have any ordinal meaning.

[0035] Also, in this specification and the like, ordinal numbers such as first, second, etc. are used for convenience, It may not indicate the process order or the stacking order. Therefore, for example, "first" can be appropriately replaced with "second" or "third" and so on for explanation. Also, the ordinal numbers described in this specification etc. may not match the ordinal numbers used to specify one aspect of the present invention. There is a case.

[0036] Also, in this specification etc., when explaining the configuration of the invention using drawings, the same reference signs may be commonly used even between different drawings.

[0037] Also, in this specification etc., the term "film" and the term "layer" can be interchanged with each other. 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". There is a case where it is possible.

[0038] Also, in this specification etc., the singlet excited state (S * ) is a singlet state having excitation energy. Also, the S1 level is the lowest level of the singlet excitation energy level and is the excitation energy level of the lowest singlet excited state (S1 state). Also, the triplet excited state (T ) is a triplet state having excitation energy. Also, the T1 level * is the lowest level of the triplet excitation energy level and is the excitation energy level of the lowest triplet excited state (T1 state). Note that in this specification etc., even when simply written as the singlet excited state and the singlet excitation energy level, it may represent the S1 state and the S1 level. Also, when written as the triplet excited state and the triplet excitation energy level, it may represent the T1 state and the T1 level. Also, when written as the triplet excited state and the triplet excitation energy level, Even in such a case, it may represent the T1 state and the T1 level.

[0039] In addition, in this specification and the like, a fluorescent compound is a compound that emits light in the visible light region when relaxing from the singlet excited state to the ground state. A phosphorescent compound is a compound 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 compound is one of the compounds capable of converting triplet excitation energy into visible light.

[0040] Note that in this specification and the like, room temperature refers to a temperature in the range of 0°C or higher and 40°C or lower.

[0041] In addition, in this specification and the like, the blue wavelength region is 400 nm or more and less than 490 nm, and blue light emission has at least one emission spectrum peak in this wavelength region. Also, the green wavelength region is 490 nm or more and less than 580 nm, and green light emission has at least one emission spectrum peak in this wavelength region. Also, the red wavelength region is 580 nm or more and 680 nm or less, and red light emission has at least one emission spectrum peak in this wavelength region.

[0042] (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 to 4.

[0043] <Configuration Example 1 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 FIG. 1.

[0044] FIG. 1(A) is a cross-sectional schematic view of a light-emitting element 150 according to one aspect of the present invention.

[0045] 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. .

[0046] Also, the EL layer 100 shown in Fig. 1(A) has, in addition to the light-emitting layer 130, 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.

[0047] In the present embodiment, among the pair of electrodes, electrode 101 is used as the anode and electrode 1 02 is used as the cathode for explanation. However, the configuration of the light-emitting element 150 is not limited to this. That is, electrode 101 may be used as the cathode, electrode 102 may be used as the anode, and the lamination of each layer between the electrodes may be in the reverse order. 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 laminated in this order. .

[0048] Note that the configuration of the EL layer 100 is not limited to the configuration shown in Fig. 1(A), and may be a configuration having 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 configuration having a functional layer having a function such as reducing the injection barrier of holes or electrons, improving the transportability of holes or electrons, inhibiting the transportability of holes or electrons, or suppressing the quenching phenomenon by the electrodes. Note that each functional layer may be a single layer or a configuration in which a plurality of layers are laminated.

[0049] Next, the light-emitting layer 130 will be described below.

[0050] ​​​In one aspect of the present invention, the light-emitting element 150 has a fluorescent compound in the light-emitting layer. It is a fluorescent light-emitting element. Fluorescent light-emitting elements have good reliability, and further, since the emission spectrum tends to be sharper compared to phosphorescent light-emitting elements, it is possible to obtain a light-emitting element with high color purity. However, in the case of an organic EL element, the generation ratio of singlet excitons and triplet excitons (hereinafter, exciton generation probability) is 1:3 due to statistical probability. Therefore, generally, in a fluorescent light-emitting element using light emission from singlet excitons, only 25% of the generated excitons can contribute to light emission. Therefore, in order to increase the efficiency of the fluorescent light-emitting element, it is important to cause triplet excitons to contribute to light emission. Here, the present inventors have found that by using an organic compound capable of converting triplet excitation energy into light emission in the light-emitting layer, an organic compound having a benzofuropyrimidine skeleton or a benzothienopyrimidine skeleton, and an organic compound exhibiting fluorescent light emission, triplet excitons can be efficiently made to contribute to fluorescent light emission, that is, a highly efficient fluorescent element can be obtained. The above-mentioned benzofuropyrimidine skeleton or benzothienopyrimidine skeleton is preferably a benzofuro[3,2-d]pyrimidine skeleton or a benzothieno[3,2-d]pyrimidine skeleton. By adopting such a configuration, the electron transport property of the organic compound can be enhanced. Further, since the LUMO (Lowest Unoccupied Molecular

[0051] Orbital, also referred to as the lowest unoccupied orbital) level of the organic compound becomes lower, the organic compound in the light-emitting layer easily receives electrons, and the driving voltage of the light-emitting element can be reduced. The above-mentioned benzofuropyrimidine skeleton or benzothienopyrimidine skeleton is preferably a benzofuro[3,2-d]pyrimidine skeleton or a benzothieno[3,2-d]pyrimidine skeleton. By adopting such a configuration, the electron transport property of the organic compound can be enhanced. Further, since the LUMO (Lowest Unoccupied Molecular Orbital, also referred to as the lowest unoccupied orbital) level of the organic compound becomes lower, the organic compound in the light-emitting layer easily receives electrons, and the driving voltage of the light-emitting element can be reduced.

[0052] The above-mentioned benzofuropyrimidine skeleton or benzothienopyrimidine skeleton is preferably a benzofuro[3,2-d]pyrimidine skeleton or a benzothieno[3,2-d]pyrimidine skeleton. By adopting such a configuration, the electron transport property of the organic compound can be enhanced. Also, since the LUMO (Lowest Unoccupied Molecular Orbital, also referred to as the lowest unoccupied orbital) level of the organic compound becomes lower, the organic compound in the light-emitting layer easily receives electrons, and the driving voltage of the light-emitting element can be reduced. When the organic compound has such a structure, the electron transport property of the organic compound can be enhanced. Also, since the LUMO (Lowest Unoccupied Molecular Orbital, also referred to as the lowest unoccupied orbital) level of the organic compound becomes lower, the organic compound in the light-emitting layer easily receives electrons, and the driving voltage of the light-emitting element can be reduced.

[0053] Further, it is preferable that the benzofuro[3,2-d]pyrimidine skeleton or benzothieno[3,2-d]pyrimidine skeleton has a substituent at the 4-position and / or 8-position. By adopting such a configuration, a light-emitting element with good luminous efficiency and further good reliability can be obtained.

[0054] As the substituent at the 4-position and / or 8-position, a substituent having a hole-transporting skeleton is preferable. Specifically, for example, a carbazole skeleton, a dibenzofuran skeleton, and a dibenzothiophene skeleton can be mentioned.

[0055] Examples of the organic compound having a function of converting the above-mentioned triplet excitation energy into light emission include compounds that can emit phosphorescence (hereinafter also referred to as phosphorescent compounds). In this specification and the like, the phosphorescent compound refers to a compound that exhibits phosphorescence and does not exhibit fluorescence at any temperature in the range from low temperature (for example, 77K) to room temperature or lower (that is, 77K or higher and 313K or lower). In order for the phosphorescent compound to efficiently convert triplet excitation energy into light emission, it preferably has a heavy atom. When the phosphorescent compound has a heavy atom, due to spin-orbit interaction (interaction between the spin angular momentum and orbital angular momentum of electrons), the transition between the singlet ground state and the triplet excited state becomes allowed. Therefore, the transition probability between the singlet ground state and the triplet excited state of the phosphorescent compound increases, so that the efficiency of light emission and the probability of absorption related to the transition can be increased. In addition, energy transfer by the Förster mechanism from the triplet excitation energy level of the phosphorescent compound to the singlet excitation energy level of the fluorescent compound is also allowed. For this purpose, the phosphorescent compound has a large spin-orbit interaction. It preferably has a metal element, specifically a transition metal element, particularly preferably a platinum group element ( ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), or platinum (Pt)), and among them, having iridium can increase the transition probability related to the direct transition between the singlet ground state and the triplet excited state, which is preferable.

[0056] In addition, examples of the material having a function of converting triplet excitation energy into light emission include thermally activated delayed fluorescence (TADF) materials. The thermally activated delayed fluorescence material means a material having a small difference between the S1 level and the T1 level and having a function of converting triplet excitation energy into singlet excitation energy by intersystem crossing. Therefore, it is possible to up-convert (intersystem crossing) triplet excitation energy into singlet excitation energy with a small amount of thermal energy and efficiently generate the singlet excited state. An exciplex (also called an exciplex or an exciplex) that forms an excited state with two kinds of substances has an extremely small difference between the S1 level and the T1 level, and has a function as a thermally activated delayed fluorescence material capable of converting triplet excitation energy into singlet excitation energy.

[0057] 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( B) shows a light-emitting layer 130 having a compound 131, a compound 132, and a compound 133. In one aspect of the present invention, the compound 131 has a function of converting triplet excitation energy into light emission. In addition, the compound 132 has a benzofuropyrimidine skeleton or a benzothienopy It is an organic compound having a pyrimidine skeleton. Compound 133 is a guest material that exhibits fluorescence emission. It is.

[0058] <Example 1 of the structure of the light-emitting layer> Figure 1(C) shows an example of the correlation of energy levels in the light-emitting layer of a light-emitting device according to an aspect of the present invention. In this configuration example, the case where a phosphorescent compound is used for Compound 131 is shown.

[0059] Further, the correlation of the energy levels of Compound 131, Compound 132, and Compound 133 in the light-emitting layer 130 is shown in Figure 1(C). Note that the notations and reference numerals in Figure 1(C) are as follows. They are as follows. ·Comp(131): Compound 131 ·Comp(132): Compound 132 ·Guest(133): Compound 133 ·T C1 : T1 level of Compound 131 ·S C2 : S1 level of Compound 132 ·T C2 : T1 level of Compound 132 ·S G : S1 level of Compound 133 ·T G : T1 level of Compound 133

[0060] In Figure 1(C), Compound 131 or Compound 132 receives holes and electrons to form an excited state. Here, since Compound 131 is a phosphorescent compound, intersystem crossing between the singlet state and the triplet state is allowed. Therefore, both the singlet excitation energy and the triplet excitation energy of Compound 132 can be rapidly transferred to Compound 131 (Route A1 in Figure 1(C)). At this time, it is preferable that S ≧T C2 C2 1(C), and T C2 ≧T C2 C2 C1 ≧T C1 ​In addition, the light-emitting layer 130 is formed by mixing compound 131, compound 132, and compound 133. However, regarding the mixing ratio of compound 131 and compound 132, it is preferable that the amount of compound 132 is larger. Specifically, it is preferably in the range of compound 131:compound 132 = 1:9 to 3:7 (weight ratio). With this configuration, compound 131 can be efficiently excited. Also, since compound 131 is a phosphorescent compound, the triplet excitation energy possessed by compound 131 can be efficiently converted into the singlet excitation energy of compound 133 (Route A2 in Fig. 1(C)). Here, as shown in Fig. 1(C), it is preferable that S≧T≧S because the singlet excitation energy can efficiently move to compound 133, which is the guest material. Also, it is preferable that T2≧T≧S because the triplet excitation energy can be efficiently converted into singlet excitation energy and move to compound 133, which is the guest material. By having this configuration, compound 131 can be excited efficiently. Also, since compound 131 is a phosphorescent compound, the triplet excitation energy possessed by compound 131 can be efficiently converted into the singlet excitation energy of compound 133 (Route A2 in Fig. 1(C)). Here, as shown in Fig. 1(C), it is preferable that S≧T≧S because the singlet excitation energy can efficiently move to compound 133, which is the guest material. Also, it is preferable that T2≧T≧S because the triplet excitation energy can be efficiently converted into singlet excitation energy and move to compound 133, which is the guest material. to the singlet excitation energy of compound 133 (Route A2 in Fig. 1(C)). Here, as shown in Fig. 1(C), it is preferable that S≧T≧S because the singlet excitation energy can efficiently move to compound 133, which is the guest material. Also, it is preferable that T2≧T≧S because the triplet excitation energy can be efficiently converted into singlet excitation energy and move to compound 133, which is the guest material. Here, as shown in Fig. 1(C), S C2 ≧T C1 ≧S G is preferable because the singlet excitation energy can efficiently move to compound 133, which is the guest material. Also, it is preferable that T C 2≧T C1 ≧S G because the triplet excitation energy can be efficiently converted into singlet excitation energy and move to compound 133, which is the guest material. is preferable because the triplet excitation energy can be efficiently converted into singlet excitation energy and move to compound 133, which is the guest material.

[0061] Also, when triplet excitation energy transfer occurs from T C1 to T G the triplet excitation energy will be deactivated (Route A3 in Fig. 1(C)). Therefore, it is preferable that the energy transfer of Route A3 is less. To suppress the energy transfer of Route A3, the weight ratio of the total amount of compound 131 and compound 132 to compound 133 is preferably such that the weight ratio of compound 133 is low. Specifically, the weight ratio of compound 133 to the total amount of compound 131 and compound 132 is preferably 0.001 or more and 0.05 or less, more preferably 0.001 or more and 0.01 or less. is deactivated (Route A3 in Fig. 1(C)). Therefore, it is preferable that the energy transfer of Route A3 is less. To suppress the energy transfer of Route A3, the weight ratio of the total amount of compound 131 and compound 132 to compound 133 is preferably such that the weight ratio of compound 133 is low. Specifically, the weight ratio of compound 133 to the total amount of compound 131 and compound 132 is preferably 0.001 or more and 0.05 or less, more preferably 0.001 or more and 0.01 or less. For suppressing the energy transfer of Route A3, the weight ratio of the total amount of compound 131 and compound 132 to compound 133 is preferably such that the weight ratio of compound 133 is low. Specifically, the weight ratio of compound 133 to the total amount of compound 131 and compound 132 is preferably 0.001 or more and 0.05 or less, more preferably 0.001 or more and 0.01 or less. For suppressing the energy transfer of Route A3, the weight ratio of the total amount of compound 131 and compound 132 to compound 133 is preferably such that the weight ratio of compound 133 is low. Specifically, the weight ratio of compound 133 to the total amount of compound 131 and compound 132 is preferably 0.001 or more and 0.05 or less, more preferably 0.001 or more and 0 .01 or less.

[0062] In addition, when the direct recombination process of carriers dominates in Compound 133, a large number of triplet excitons will be generated in Compound 13 3, which will reduce the luminescence efficiency due to thermal deactivation . Therefore, it is preferable that the proportion of the energy transfer process via Route A 2 is larger than the direct recombination process of carriers in Compound 133, because it can reduce the generation probability of the triplet excited state of Compound 133 and suppress thermal deactivation. For this purpose, the weight ratio of the total amount of Compound 131 and Compound 132 to Compound 133 is preferably low. Specifically, the weight ratio of Compound 133 to the total amount of Compound 131 and Compound 132 is preferably 0.001 or more and 0.05 or less, more preferably 0.001 or more and 0.01 or less. By configuring the light-emitting layer 130 as described above, the light emission from the fluorescent compound in the light-emitting layer 130 can be obtained with high efficiency. Also, T is preferably 2.0 eV or less. By adopting this configuration, a light-emitting device with good reliability can be obtained.

[0063] In the above configuration, since it is not necessary to use a material with a high luminescence quantum yield for the phosphorescent compound, the material design becomes easy and the range of material selection is widened. Specifically, the luminescence quantum yield of the compound may be 0% or more and 50% or less, 0% or more and 40% or less

[0064] at room temperature or normal temperature, 0% or more and 25% or less, 0% or more and 10% or less, or even G 0% or more and 1% or less.

[0065] In the above configuration, since it is not necessary to use a material with a high luminescence quantum yield for the phosphorescent compound, the material design becomes easy and the range of material selection is widened. Specifically, the luminescence quantum yield of the compound may be 0% or more and 50% or less, 0% or more and 40% or less at room temperature or normal temperature, 0% or more and 25% or less, 0% or more and 10% or less, or even 0% or more and 1% or less.

[0066] As described above, among the organic compounds having a benzofuropyrimidine skeleton or a benzothienopyrimidine skeleton, the organic compounds having a benzofuro[3,2-d]pyrimidine skeleton or a benzothieno[3,2-d]pyrimidine skeleton have a low LUMO level. Therefore, the organic compound can be suitably used as the compound 132 having electron transporting properties. Among the organic compounds having a benzofuro[3,2-d]pyrimidine skeleton or a benzothieno[3,2-d]pyrimidine skeleton, the organic compounds having a benzofuro[3,2-d]pyrimidine skeleton or a benzothieno[3,2-d]pyrimidine skeleton have a low LUMO level. Therefore, the organic compound can be suitably used as the compound 132 having electron transporting properties. Among the organic compounds having a benzofuropyrimidine skeleton or a benzothienopyrimidine skeleton, the organic compounds having a benzofuro[3,2-d]pyrimidine skeleton or a benzothieno[3,2-d]pyrimidine skeleton have a low LUMO level. Therefore, the organic compound can be suitably used as the compound 132 having electron transporting properties. Among the organic compounds having a benzofuropyrimidine skeleton or a benzothienopyrimidine skeleton, the organic compounds having a benzofuro[3,2-d]pyrimidine skeleton or a benzothieno[3,2-d]pyrimidine skeleton have a low LUMO level. Therefore, the organic compound can be suitably used as the compound 132 having electron transporting properties.

[0067] <Configuration Example 2 of Light Emitting Layer> FIG. 2(B) is an example of the energy level correlation in the light emitting layer 130 of the light emitting device 150 according to one embodiment of the present invention. In this configuration example, a phosphorescent compound is used for the compound 131, and the case where the compound 131 and the compound 132 form an exciplex is shown. FIG. 2(B) is an example of the energy level correlation in the light emitting layer 130 of the light emitting device 150 according to one embodiment of the present invention. In this configuration example, a phosphorescent compound is used for the compound 131, and the case where the compound 131 and the compound 132 form an exciplex is shown. FIG. 2(B) is an example of the energy level correlation in the light emitting layer 130 of the light emitting device 150 according to one embodiment of the present invention. In this configuration example, a phosphorescent compound is used for the compound 131, and the case where the compound 131 and the compound 132 form an exciplex is shown.

[0068] The combination of the compound 131 and the compound 132 may be any combination that can form an exciplex, but it is more preferable that one is a compound having hole transporting properties and the other is a compound having electron transporting properties. In this case, it becomes easy to form a donor-acceptor type exciplex, and the exciplex can be efficiently formed. Further, when the combination of the compound 131 and the compound 132 is a combination of a compound having hole transporting properties and a compound having electron transporting properties, the carrier balance can be easily controlled by the mixing ratio. Specifically, the range of compound having hole transporting properties: compound having electron transporting properties = 1:9 to 9:1 (weight ratio) is preferable. Further, since the carrier balance can be easily controlled by having this configuration, the control of the carrier recombination region can also be easily performed. The combination of the compound 131 and the compound 132 may be any combination that can form an exciplex, but it is more preferable that one is a compound having hole transporting properties and the other is a compound having electron transporting properties. In this case, it becomes easy to form a donor-acceptor type exciplex, and the exciplex can be efficiently formed. Further, when the combination of the compound 131 and the compound 132 is a combination of a compound having hole transporting properties and a compound having electron transporting properties, the carrier balance can be easily controlled by the mixing ratio. Specifically, the range of compound having hole transporting properties: compound having electron transporting properties = 1:9 to 9:1 (weight ratio) is preferable. Further, since the carrier balance can be easily controlled by having this configuration, the control of the carrier recombination region can also be easily performed. The combination of the compound 131 and the compound 132 may be any combination that can form an exciplex, but it is more preferable that one is a compound having hole transporting properties and the other is a compound having electron transporting properties. In this case, it becomes easy to form a donor-acceptor type exciplex, and the exciplex can be efficiently formed. Further, when the combination of the compound 131 and the compound 132 is a combination of a compound having hole transporting properties and a compound having electron transporting properties, the carrier balance can be easily controlled by the mixing ratio. Specifically, the range of compound having hole transporting properties: compound having electron transporting properties = 1:9 to 9:1 (weight ratio) is preferable. Further, since the carrier balance can be easily controlled by having this configuration, the control of the carrier recombination region can also be easily performed. The combination of the compound 131 and the compound 132 may be any combination that can form an exciplex, but it is more preferable that one is a compound having hole transporting properties and the other is a compound having electron transporting properties. In this case, it becomes easy to form a donor-acceptor type exciplex, and the exciplex can be efficiently formed. Further, when the combination of the compound 131 and the compound 132 is a combination of a compound having hole transporting properties and a compound having electron transporting properties, the carrier balance can be easily controlled by the mixing ratio. Specifically, the range of compound having hole transporting properties: compound having electron transporting properties = 1:9 to 9:1 (weight ratio) is preferable. Further, since the carrier balance can be easily controlled by having this configuration, the control of the carrier recombination region can also be easily performed. The combination of the compound 131 and the compound 132 may be any combination that can form an exciplex, but it is more preferable that one is a compound having hole transporting properties and the other is a compound having electron transporting properties. In this case, it becomes easy to form a donor-acceptor type exciplex, and the exciplex can be efficiently formed. Further, when the combination of the compound 131 and the compound 132 is a combination of a compound having hole transporting properties and a compound having electron transporting properties, the carrier balance can be easily controlled by the mixing ratio. Specifically, the range of compound having hole transporting properties: compound having electron transporting properties = 1:9 to 9:1 (weight ratio) is preferable. Further, since the carrier balance can be easily controlled by having this configuration, the control of the carrier recombination region can also be easily performed. The combination of the compound 131 and the compound 132 may be any combination that can form an exciplex, but it is more preferable that one is a compound having hole transporting properties and the other is a compound having electron transporting properties. In this case, it becomes easy to form a donor-acceptor type exciplex, and the exciplex can be efficiently formed. Further, when the combination of the compound 131 and the compound 132 is a combination of a compound having hole transporting properties and a compound having electron transporting properties, the carrier balance can be easily controlled by the mixing ratio. Specifically, the range of compound having hole transporting properties: compound having electron transporting properties = 1:9 to 9:1 (weight ratio) is preferable. Further, since the carrier balance can be easily controlled by having this configuration, the control of the carrier recombination region can also be easily performed. The combination of the compound 131 and the compound 132 may be any combination that can form an exciplex, but it is more preferable that one is a compound having hole transporting properties and the other is a compound having electron transporting properties. In this case, it becomes easy to form a donor-acceptor type exciplex, and the exciplex can be efficiently formed. Further, when the combination of the compound 131 and the compound 132 is a combination of a compound having hole transporting properties and a compound having electron transporting properties, the carrier balance can be easily controlled by the mixing ratio. Specifically, the range of compound having hole transporting properties: compound having electron transporting properties = 1:9 to 9:1 (weight ratio) is preferable. Further, since the carrier balance can be easily controlled by having this configuration, the control of the carrier recombination region can also be easily performed. The combination of the compound 131 and the compound 132 may be any combination that can form an exciplex, but it is more preferable that one is a compound having hole transporting properties and the other is a compound having electron transporting properties. In this case, it becomes easy to form a donor-acceptor type exciplex, and the exciplex can be efficiently formed. Further, when the combination of the compound 131 and the compound 132 is a combination of a compound having hole transporting properties and a compound having electron transporting properties, the carrier balance can be easily controlled by the mixing ratio. Specifically, the range of compound having hole transporting properties: compound having electron transporting properties = 1:9 to 9:1 (weight ratio) is preferable. Further, since the carrier balance can be easily controlled by having this configuration, the control of the carrier recombination region can also be easily performed. The combination of the compound 131 and the compound 132 may be any combination that can form an exciplex, but it is more preferable that one is a compound having hole transporting properties and the other is a compound having electron transporting properties. In this case, it becomes easy to form a donor-acceptor type exciplex, and the exciplex can be efficiently formed. Further, when the combination of the compound 131 and the compound 132 is a combination of a compound having hole transporting properties and a compound having electron transporting properties, the carrier balance can be easily controlled by the mixing ratio. Specifically, the range of compound having hole transporting properties: compound having electron transporting properties = 1:9 to 9:1 (weight ratio) is preferable. Further, since the carrier balance can be easily controlled by having this configuration, the control of the carrier recombination region can also be easily performed. The combination of the compound 131 and the compound 132 may be any combination that can form an exciplex, but it is more preferable that one is a compound having hole transporting properties and the other is a compound having electron transporting properties. In this case, it becomes easy to form a donor-acceptor type exciplex, and the exciplex can be efficiently formed. Further, when the combination of the compound 131 and the compound 132 is a combination of a compound having hole transporting properties and a compound having electron transporting properties, the carrier balance can be easily controlled by the mixing ratio. Specifically, the range of compound having hole transporting properties: compound having electron transporting properties = 1:9 to 9:1 (weight ratio) is preferable. Further, since the carrier balance can be easily controlled by having this configuration, the control of the carrier recombination region can also be easily performed.

[0069] Note that the formation of the exciplex can be confirmed, for example, by the emission spectrum of the compound 131, the emission spectrum of the compound 132, Compare the spectra and the emission spectra of the mixed films obtained by mixing these compounds, and confirm by observing that the emission spectrum of the mixed film is shifted to a longer wavelength (or has a new peak on the longer wavelength side) than the emission spectra of the respective compounds. Alternatively, it can be confirmed by comparing the transient photoluminescence (PL) of Compound 131, the transient PL of Compound 132, and the transient PL of the mixed film obtained by mixing these compounds, and observing differences in the transient responses such as that the transient PL lifetime of the mixed film has a longer lifetime component than the transient PL lifetimes of the respective compounds, or that the ratio of the delayed component increases. Alternatively, it can be confirmed by comparing the transient photoluminescence (PL) of Compound 131, the transient PL of Compound 132, and the transient PL of the mixed film obtained by mixing these compounds, and observing differences in the transient responses such as that the transient PL lifetime of the mixed film has a longer lifetime component than the transient PL lifetimes of the respective compounds, or that the ratio of the delayed component increases. it can be confirmed by comparing the transient photoluminescence (PL) of Compound 131, the transient PL of Compound 132, and the transient PL of the mixed film obtained by mixing these compounds, and observing differences in the transient responses such as that the transient PL lifetime of the mixed film has a longer lifetime component than the transient PL lifetimes of the respective compounds, or that the ratio of the delayed component increases. it can be confirmed by comparing the transient photoluminescence (PL) of Compound 131, the transient PL of Compound 132, and the transient PL of the mixed film obtained by mixing these compounds, and observing differences in the transient responses such as that the transient PL lifetime of the mixed film has a longer lifetime component than the transient PL lifetimes of the respective compounds, or that the ratio of the delayed component increases. it can be confirmed by comparing the transient photoluminescence (PL) of Compound 131, the transient PL of Compound 132, and the transient PL of the mixed film obtained by mixing these compounds, and observing differences in the transient responses such as that the transient PL lifetime of the mixed film has a longer lifetime component than the transient PL lifetimes of the respective compounds, or that the ratio of the delayed component increases.

[0070] As a combination of materials that efficiently form an exciplex, it is preferable that the HOMO (Highest Occupied Molecular Orbital, also referred to as the highest occupied orbital) level of one of Compound 131 and Compound 132 is higher than the HOMO level of the other, and that the LUMO level of one is higher than the LUMO level of the other. Specifically, the energy difference between the HOMO level of Compound 131 and the HOMO level of Compound 132 is preferably 0.1 eV or more, more preferably 0.2 eV or more, and still more preferably 0.3 eV or more. Also, the energy difference between the LUMO level of Compound 131 and the LUMO level of Compound 132 is preferably 0.1 eV or more, more preferably 0.2 eV or more, and still more preferably 0.3 eV or more. By setting such a correlation of energy levels, eV or more, more preferably 0.2 eV or more, and still more preferably 0.3 eV or more. Also, the energy difference between the LUMO level of Compound 131 and the LUMO level of Compound 132 is preferably 0.1 eV or more, more preferably 0.2 eV or more, and still more preferably 0.3 eV or more. By setting such a correlation of energy levels, eV or more, more preferably 0.2 eV or more, and still more preferably 0.3 eV or more. Also, the energy difference between the LUMO level of Compound 131 and the LUMO level of Compound 132 is preferably 0.1 eV or more, more preferably 0.2 eV or more, and still more preferably 0.3 eV or more. By setting such a correlation of energy levels, eV or more, more preferably 0.2 eV or more, and still more preferably 0.3 eV or more. By setting such a correlation of energy levels, eV or more, more preferably 0.2 eV or more, and still more preferably 0.3 eV or more. By setting such a correlation of energy levels, holes and electrons, which are carriers injected from a pair of electrodes (Electrode 101 and Electrode 102), are more likely to be injected into Compound 131 and Compound 132, respectively, which is preferable. Note that holes and electrons, which are carriers injected from a pair of electrodes (Electrode 101 and Electrode 102), are more likely to be injected into Compound 131 and Compound 132, respectively, which is preferable. Note that , the HOMO level of Compound 131 may be equivalent to the HOMO level of Compound 132, or the LUMO level of Compound 13 1 may be equivalent to the LUMO level of Compound 132.

[0071] Note that the LUMO level and HOMO level of the compound can be derived from the electrochemical properties (reduction potential and oxidation potential) of the compound measured by cyclic voltammetry (C V) measurement. It can be done.

[0072] For example, when Compound 131 has hole-transporting properties and Compound 132 has electron-transporting properties, As shown in the energy band diagram of Fig. 2(A), it is preferable that the HOMO level of Compound 131 is higher than the HOMO level of Compound 1 32, and it is preferable that the LUMO level of Compound 131 is higher than the LUMO level of Compound 13 2. With such a correlation of energy levels, holes and electrons, which are carriers injected from a pair of electrodes (Electrode 101 and Electrode 102), are easily injected into Compound 131 and Compound 132, respectively, which is preferable.

[0073] Note that in Fig. 2(A), Comp(131) represents Compound 131, Comp(1 32) represents Compound 132, and ΔE C1 represents the energy difference between the LUMO level and the HOMO level of Compound 131, ΔE C2 represents the energy difference between the LUMO level and the HOMO level of Compound 132, and ΔE E represents the energy difference between the LUMO level of Compound 132 and the HOMO level of Compound 131. These are notations and symbols.

[0074] In addition, the exciplex formed by Compound 131 and Compound 132 has a HOMO in Compound 131 and compound 132 becomes an exciplex having a LUMO molecular orbital. The excitation energy of the exciplex is the LUMO level of compound 132 and the HOMO level of compound 131. Energy difference between the levels (ΔE E ) and the LUMO and HOMO levels of compound 131 are Energy difference between the levels (ΔE C1 ) and the relationship between the LUMO and HOMO levels of compound 132 Energy difference (ΔE C2 ) is smaller than that of Compound 131 and Compound 132. By forming an exciplex at , it is possible to form an excited state at a lower excitation energy. In addition, since the excitation energy is lower, the exciplex has a stable excited state. It can be formed.

[0075] In addition, the compounds 131, 132, and 133 in the light-emitting layer 130 The correlation between the energy levels is shown in Figure 2(B). The notations and symbols in Figure 2(B) are as follows: The other notations and symbols are the same as those shown in FIG. 1(C). ·S C1 : S1 level of compound 131 ·S E : S1 level of the exciplex T E :T1 level of the exciplex

[0076] In the light-emitting element of one embodiment of the present invention shown in this configuration example, the compound contained in the light-emitting layer 130 Compound 131 and compound 132 form an exciplex. The S1 level of the exciplex (S E ) and exciplexes T1 level (T E ) are adjacent energy levels (Figure 2(B) Route A See 4).

[0077] The exciplexes formed by the above process can emit light or transfer the excitation energy to other materials. When an electron goes to the ground state by losing excitation energy, such as by donating it to a nucleon, it forms an exciplex. The two substances that were once separated will once again behave as separate substances.

[0078] Excitation energy levels of exciplexes (S E and T E ) is a compound that forms an exciplex. The S1 levels (S C1 and S C2 ) is lower, It is possible to form an excited state with lower excitation energy. This allows the luminescent element The driving voltage of the element 150 can be reduced.

[0079] The S1 level of the exciplex (S E ) and T1 level (T E ) are adjacent energy levels Therefore, the exciplex has the function of exhibiting thermally activated delayed fluorescence. It has the function of converting energy into singlet excitation energy by upconversion. Therefore, a part of the triplet excitation energy generated in the light-emitting layer 130 is absorbed by the exciplex. To do this, the S1 level (S E ) and T1 standard Place(T E The energy difference between the two is preferably greater than 0 eV and less than 0.2 eV, more preferably The electron energy is preferably greater than 0 eV or less than 0.1 eV. To do this, the T1 level of the exciplex (T E ) are each compound that forms an exciplex (compound 131 and and compound 132) T1 level (T C1 and T C2 ) is preferable. The triplet excitation energy of the exciplexes by compounds 131 and 132 was quenched by The exciplex efficiently converts triplet excitation energy into singlet excitation energy. Reverse intersystem crossing to the energy occurs.

[0080] In addition, the singlet excited energy level of the exciplex (S E ) is a light-emitting material, compound 133 The singlet excited energy level (S G ) is preferable. By assuming a correlation between the positions, the singlet excitation energy of the generated exciplex is Excitation energy level (S E ) to the singlet excited energy level (S G )Hehe Energy can be transferred.

[0081] In this case, the correlation between the energy levels of compounds 131 and 132 is limited to that shown in FIG. 2(B). That is, the singlet excited energy level (S C1 ) is a compound The singlet excited energy level of 132 (S C2 ) may be higher or lower. The triplet excited energy level of 131 (T C1 ) is the triplet excitation energy of compound 132 Level (T C2 ) may be higher or lower.

[0082] In one embodiment of the present invention, a phosphorescent compound is added to one of the compounds forming the exciplex. Because of this, intersystem crossing between the singlet and triplet states is permitted. It is possible to form an exciplex that can undergo a transition from an excited state to a singlet ground state. In this case, the triplet excited energy level of the exciplex (T E ) is one of the light-emitting materials, compound 133. It is preferably higher than the triplet excitation energy level (S G ). By correlating such energy levels, the triplet excitation energy of the generated exciplex can be transferred from the triplet excitation energy level (T ) of the exciplex to the singlet excitation energy level (S ) of Compound 133. Note that since the S1 level (S E ) and the T1 level (T G ) of the exciplex are adjacent energy levels to each other, it may be difficult to clearly distinguish fluorescence and phosphorescence in the emission spectrum. In that case, fluorescence or phosphorescence may be distinguishable by the emission lifetime. ). Note that since the S1 level (S E ) and the T1 level (T E ) of the exciplex are adjacent energy levels to each other, it may be difficult to clearly distinguish fluorescence and phosphorescence in the emission spectrum. In that case, fluorescence or phosphorescence may be distinguishable by the emission lifetime. are adjacent energy levels to each other, it may be difficult to clearly distinguish fluorescence and phosphorescence in the emission spectrum. In that case, fluorescence or phosphorescence may be distinguishable by the emission lifetime. In some cases, it may be possible to distinguish between fluorescence and phosphorescence by the emission lifetime. In some cases, it may be possible to distinguish between fluorescence and phosphorescence by the emission lifetime.

[0083] Through the above-described energy transfer process, Compound 133 can be in the singlet excited state and emit light (see Route A5 in Fig. 2(B)). (see Route A5 in Fig. 2(B)).

[0084] Also, when triplet excitation energy transfer occurs from T E to T G , the triplet excitation energy will be deactivated (Route A6 in Fig. 2(B)). Therefore, it is preferable that the energy transfer of Route A6 is less. To suppress the energy transfer of Route A6, the weight ratio of the total amount of Compound 131 and Compound 132 to Compound 133 is preferably low in terms of the weight ratio of Compound 133. Specifically, the weight ratio of Compound 133 to the total amount of Compound 131 and Compound 132 is preferably 0.001 or more and 0.05 or less, more preferably 0.001 or more and 0.01 or less. is deactivated (Route A6 in Fig. 2(B)). Therefore, it is preferable that the energy transfer of Route A6 is less. To suppress the energy transfer of Route A6, the weight ratio of the total amount of Compound 131 and Compound 132 to Compound 133 is preferably low in terms of the weight ratio of Compound 133. Specifically, the weight ratio of Compound 133 to the total amount of Compound 131 and Compound 132 is preferably 0.001 or more and 0.05 or less, more preferably 0.001 or more and 0.01 or less. To suppress the energy transfer of Route A6, the weight ratio of the total amount of Compound 131 and Compound 132 to Compound 133 is preferably low in terms of the weight ratio of Compound 133. Specifically, the weight ratio of Compound 133 to the total amount of Compound 131 and Compound 132 is preferably 0.001 or more and 0.05 or less, more preferably 0.001 or more and 0.01 or less. To suppress the energy transfer of Route A6, the weight ratio of the total amount of Compound 131 and Compound 132 to Compound 133 is preferably low in terms of the weight ratio of Compound 133. Specifically, the weight ratio of Compound 133 to the total amount of Compound 131 and Compound 132 is preferably 0.001 or more and 0.05 or less, more preferably 0.001 or more and 0.01 or less. is preferably 0.001 or more and 0.05 or less, more preferably 0.001 or more and 0.01 or less. is preferably 0.001 or more and 0.05 or less, more preferably 0.001 or more and 0.01 or less. 01 or less.

[0085] Note that when the direct recombination process of carriers dominates in Compound 133, Compound 13 In 3, a large number of triplet excitons are generated, and the emission efficiency is reduced due to thermal deactivation. Therefore, rather than a direct recombination process of carriers in compound 133, the exciplex The higher the ratio of the energy transfer process via the formation process of 1, the greater the reaction rate. The probability of generating the triplet excited state of compound 133 can be reduced, and thermal deactivation can be suppressed. For this purpose, the total amount of Compound 131 and Compound 132 and the total amount of Compound 13 are preferably The weight ratio of compound 133 to compound 131 is preferably low. The weight ratio of compound 133 to the total amount of compound 132 is preferably 0.001 or more and It is 0.05 or less, and more preferably between 0.001 and 0.01.

[0086] Also, T G It is preferable that the wavelength is 2.0 eV or less. By adopting this configuration, the light emission with good reliability can be achieved. The element can be obtained.

[0087] Note that compound 131 has an electron transporting property, and compound 132 has a hole transporting property. In this case, the HOMO level of compound 132 may be higher than the HOMO level of compound 131. It is preferable that the LUMO level of compound 132 is higher than the LUMO level of compound 131. It is preferable that

[0088] In addition, the weight ratio of compound 131 to compound 132 is low. It is preferred that the weight ratio of compound 131 to compound 132 is preferably 0.0 The ratio is 1 or more and 0.5 or less, and more preferably 0.05 or more and 0.3 or less.

[0089] As described above, all of the energy transfer processes in routes A4 and A5 described above occur efficiently. Then, since both the singlet excitation energy and the triplet excitation energy generated in the light-emitting layer 130 are efficiently converted into the energy of the singlet excited state of the compound 133, the light-emitting device 150 can emit light with high luminous efficiency.

[0090] Further, in the light-emitting device according to one aspect of the present invention, the benzofuropyrimidine skeleton or benzothienopyrimidine skeleton of the compound 132 is preferably a benzofuro[3,2-d]pyrimidine skeleton or benzothieno[3,2-d]pyrimidine skeleton. With such a configuration, the LUMO level of the compound 132 becomes lower, which is suitable for the formation of an exciplex.

[0091] Also, it is preferable that the benzofuro[3,2-d]pyrimidine skeleton or benzothieno[3,2-d]pyrimidine skeleton has a substituent at the 4-position and / or 8-position. With such a configuration, the LUMO level of the compound 132 becomes lower, which is suitable for the formation of an exciplex.

[0092] The processes of Route A4 and A5 shown above are sometimes referred to as ExSET (Excimer-Singlet Energy Transfer) or ExEF (Excimer-Enhanced Fluorescence) 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 fluorescent compound.

[0093] By configuring the light-emitting layer 130 as described above, light emission from the fluorescent compound can be efficiently obtained.

[0094] <Configuration Example 3 of Light-Emitting Layer> FIG. 3 is an example of the correlation of energy levels in the light-emitting layer of the light-emitting device according to one aspect of the present invention. This configuration example shows the case where a thermally activated delayed fluorescence material is used for Compound 131. Note that the notations and reference numerals in FIG. 3 are the same as those shown in FIG. 1(C). ·S C1 : S1 level of Compound 131

[0095] In FIG. 3, Compound 131 or Compound 132 forms an excited state by receiving holes and electrons. Also, the excitation energy of Compound 132 can quickly move to Compound 131 (Route A7). At this time, it is preferable that S C2 ≧ S C1 , T C2 ≧ T C1 Here, the light-emitting layer 130 is formed by mixing Compound 131, Compound 132, and Compound 133. However, the mixing ratio of Compound 131 and Compound 132 is preferably higher in Compound 132. Specifically, it is preferable that Compound 131:Compound 132 = 1:9 to 3:7 (weight ratio). With this configuration, Compound 131 can be efficiently excited. Here, since Compound 131 is a thermally activated delayed fluorescence material, the triplet excitation energy possessed by Compound 131 is up-converted to singlet excitation energy at a temperature around room temperature (Route A8). Also, the energy transfer (Route A9) from the singlet excitation energy level (S C1 ) of Compound 131 to the singlet excitation energy level (S ) of Compound 133 G is allowed. Therefore, by passing through the processes of Route A8 and Route A9, the triplet excitation energy of Compound 131 can be energy-transferred to the singlet excitation energy level (S G ) of Compound 133. Here, as shown in FIG. 3, T C2 ≧ T C1 ≧ S Gis the singlet excitation energy It is preferable that both the triplet excitation energy and the singlet excitation energy efficiently transfer from Compound 131 and Compound 132 to Compound 133, which is a host material.

[0096] In order to efficiently proceed with the above upconversion, the energy difference between the S 1 level (S C1 ) and the T1 level (T C1 ) of the thermally activated delayed fluorescence material is preferably greater than 0 eV and equal to or less than 0.2 eV, more preferably greater than 0 eV and equal to or less than 0.1 eV.

[0097] Also, when triplet excitation energy transfer occurs from T C2 to T G , the triplet excitation energy is deactivated (Fig. 3, Route A 10 ). Therefore, it is preferable that the energy transfer of Route A 10 is less. In order to suppress the energy transfer of Route A , it is preferable that the energy difference between T 10 and T C1 is large. For this purpose, it is preferable that T G is 2.0 eV or less. By adopting such a configuration, a light-emitting device with good luminous efficiency and good reliability can be obtained . G . By configuring the light-emitting layer 130 as described above, light emission from the fluorescent compound in the light-emitting layer 130 can be efficiently obtained.

[0098] By configuring the light-emitting layer 130 as described above, light emission from the fluorescent compound in the light-emitting layer 130 can be efficiently obtained.

[0099] <Configuration Example 4 of Light-Emitting Layer> Fig. 4(A) shows the case where four materials are used in the light-emitting layer 130. In Fig. 4(A) , the light-emitting layer 130 includes Compound 131, Compound 132, Compound 133, and Compound 134. has. In one aspect of the present invention, Compound 131 has a function of converting triplet excitation energy into light emission. Compound 132 is an organic compound having a benzofuropyrimidine skeleton or a benzothieno[2,3-d]pyrimidine skeleton. Compound 133 is a guest material that exhibits fluorescence emission. Compound 134 is an organic compound that forms an exciplex with Compound 132. .

[0100] In addition, the correlation of the energy levels of Compound 131, Compound 132, Compound 133, and Compound 134 in the light-emitting layer 130 is shown in FIG. 4(B). The notations and symbols in FIG. 4(B) are as follows, and other notations and symbols are the same as those shown in FIG. 2(B). · S : S1 level of Compound 134 · T : T1 level of Compound 134 C3 In the light-emitting element of one aspect of the present invention shown in this configuration example, Compound 132 and Compound 134 in the light-emitting layer 130 form an exciplex. The S1 level (S ) and the T1 level (T C3 ) of the exciplex are adjacent energy levels to each other (see Route A in FIG. 4(B)).

[0101] As described above, the exciplex generated by the above process loses excitation energy, and the two substances that formed the exciplex behave as the original separate substances again. The excitation energy levels (S E ) and T ) of the exciplex are the S1 levels (S E ) of the substances (Compound 132 and Compound 134) that form the exciplex. 11 Reference).

[0102] The exciplex generated by the above process loses excitation energy as described above, and the two substances that formed the exciplex behave as the original separate substances again. The two substances that formed the exciplex behave as the original separate substances again.

[0103] The excitation energy levels (S E ) and T E ) of the exciplex are the S1 levels (S ) of the substances (Compound 132 and Compound 134) that form the exciplex.C2 and S C3 ) is lower, It is possible to form an excited state with lower excitation energy. This allows the luminescent element The driving voltage of the element 150 can be reduced.

[0104] Here, since compound 131 is a phosphorescent compound, the intersystem between the singlet state and the triplet state is Crossover is allowed. Therefore, the singlet excitation energy and triplet excitation energy of the exciplex are Both the energy and the cations are rapidly transferred to compound 131 (Route A). 12 ). At this time, T E ≧T C1 In addition, the triplet excitation energy of compound 131 can be efficiently converted to The singlet excitation energy of compound 133 can be converted directly into the singlet excitation energy of compound 133 (Route A). 13 ).child As shown in FIG. 4(B), T E ≧T C1 ≧S G Then, the excitation energy of compound 131 is The energy is efficiently transferred to the guest material, compound 133, as singlet excitation energy. Therefore, it is preferable.

[0105] In this case, the combination of Compound 132 and Compound 134 can form an exciplex. Any possible combination is acceptable, but one of them is a compound having hole transport properties and the other is an electron It is more preferable that the compound has a transport property. In this case, the compound is a donor-acceptor type. This makes it easier to form an exciplex, and the exciplex can be formed efficiently. The combination of Compound 132 and Compound 134 is a compound having hole transport properties and a compound having electron transport properties. When a compound that can be used in combination with a carrier is used, the carrier balance can be easily controlled by changing the mixture ratio. It becomes possible to control. Specifically, a compound having hole transporting properties: a compound having electron transporting properties Compound = 1:9 to 9:1 (weight ratio) is preferable. Further, by having such a configuration, Since the carrier balance can be easily controlled, the control of the carrier recombination region can also be easily performed.

[0106] In addition, as a combination of materials that efficiently form an exciplex, one of the HOMO levels of Compound 132 and Compound 134 is preferably higher than the other HOMO level, and one of the LUMO levels is preferably higher than the other LUMO level. Specifically, the energy difference between the HOMO level of Compound 132 and the HOMO level of Compound 134 is preferably 0.1 eV or more, more preferably 0.2 eV or more, and even more preferably 0.3 eV or more. Also the energy difference between the LUMO level of Compound 132 and the LUMO level of Compound 134 is preferably 0.1 eV or more, more preferably 0.2 eV or more, and even more preferably 0.3 eV or more. By having such a correlation of energy levels, holes and electrons, which are carriers injected from a pair of electrodes (electrode 101 and electrode 102), are easily injected into Compound 13 2 and Compound 134, respectively, which is preferable. Note that the HOMO level of Compound 132 may be equivalent to the HOMO level of Compound 134, or the LUMO level of Compound 132 may be equivalent to the LUMO level of Compound 134.

[0107] In addition, the correlation of the energy levels between Compound 132 and Compound 134 is not limited to FIG. 4(B). That is, the singlet excitation energy level (S ) of Compound 132 is C2 Compound 13 4's singlet excitation energy level (S C3It may be higher or lower. Also, Compound 13 The triplet excitation energy level (T C1 ) of 1 may be higher or lower than the triplet excitation energy level (T C3 ) of Compound 134.

[0108] In addition, in the light-emitting element according to one aspect of the present invention, the benzofuropyrimidine skeleton or benzothienopyrimidine skeleton possessed by Compound 132 is preferably a benzofuro[3,2-d]pyrimidine skeleton or benzothieno[3,2-d]pyrimidine skeleton. With this configuration , the LUMO level of Compound 132 becomes low, which is suitable for the formation of an exciplex.

[0109] In addition, it is preferable that the benzofuro[3,2-d]pyrimidine skeleton or benzothieno[3,2-d]pyrimidine skeleton has a substituent at the 4-position and / or 8-position. By having this configuration , the LUMO level of Compound 132 becomes low, which is suitable for the formation of an exciplex.

[0110] In addition, when triplet excitation energy transfer occurs from T C1 to T G , the triplet excitation energy is deactivated (Fig. 4(B), Route A 14 ). Therefore, it is preferable that the energy transfer of Route A 14 is less. To suppress the energy transfer of Route A , the weight ratio of the total amount of Compound 1 14 31, Compound 132 and Compound 134 to Compound 133 is preferably low in the weight ratio of Compound 133 . Specifically, the weight ratio of Compound 133 to the total amount of Compound 131, Compound 132 and Compound 13 4 is preferably 0.001 or more and 0.05 or less with respect to the total amount, and more preferably 0.001 or more and 0.01 or less.

[0111] Also, T G is preferably 2.0 eV or less. With this configuration, a light-emitting element with good reliability can be obtained.

[0112] <Energy transfer mechanism> Here, the governing factors of the intermolecular energy transfer process will be explained. Regarding the intermolecular energy transfer mechanism, two mechanisms, the Förster mechanism (dipole-dipole interaction) and the Dexter mechanism (electron exchange interaction), have been proposed. Here, regarding the donation of excitation energy from the first material in the excited state to the second material in the ground state, the intermolecular energy transfer process between the first material and the second material will be explained. The same applies when either one is an exciplex .

[0113] ≪Förster mechanism≫ In the Förster mechanism, energy transfer does not require direct contact between molecules. Energy transfer occurs through the resonance phenomenon of the dipole vibrations of the first material and the second material. Due to the resonance phenomenon of the dipole vibrations, the first material transfers energy to the second material, the first material in the excited state becomes the ground state, and the second material in the ground state becomes the excited state. Note that the rate constant k of the Förster mechanism is shown in Equation (1). of the Förster mechanism is shown in Equation (1). h*→g is shown in Equation (1).

[0114]

Equation

[0115] In Equation (1), ν represents the frequency, and f’ h (ν) is the normalized emission spectrum of the first material (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 represented by the phosphorescence spectrum), and ε g ( ν) represents the molar extinction coefficient of the second material, N represents Avogadro's number, n represents the refractive index of the medium, R represents the intermolecular distance between the first material and the second material, τ represents the measured lifetime of the excited state (fluorescence lifetime or phosphorescence lifetime), c represents the speed of light, φ represents the luminescence quantum yield (when discussing energy transfer from the singlet excited state, it is the fluorescence quantum yield; when discussing energy transfer from the triplet excited state, it is the phosphorescence quantum yield), and K When discussing energy transfer from the triplet excited state, it is the fluorescence quantum yield; when discussing energy transfer from the triplet excited state, it is the phosphorescence quantum yield), and K is a coefficient (ranging from 0 to 4) representing the orientation of the transition dipole moments of the first material and the second material. In the case of random orientation, 2 K = 2 / 3. In the case of 2 random orientation, K = 2 / 3.

[0116] ≪Dexter mechanism≫ In the Dexter mechanism, the first material and the second material approach within the contact effective distance where orbital overlap occurs, and energy transfer occurs through the exchange of electrons between the excited-state electrons of the first material and the ground-state electrons of the second material. The rate constant k of the Dexter mechanism is shown in Equation (2) . h*→g as shown in Equation (2) .

[0117]

Equation

[0118] In Equation (2), h is Planck's constant, K is a constant with the dimension of energy , ν represents the frequency, and f’ h (ν) represents the normalized emission spectrum of the first material (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), and ε’ 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), and ε’ represents the molar extinction coefficient of the second material, and the rest of the symbols have the same meanings as described above. g(ν) represents the normalized absorption spectrum of the second material, L represents the effective molecular radius, and R represents the first intermolecular distance between the first material and the second material.

[0119] Here, the energy transfer efficiency φ ET from the first material to the second material is expressed by Equation (3). k r represents the rate constant of the emission process of the first material (fluorescence when discussing energy transfer from the singlet excited state, phosphorescence when discussing energy transfer from the triplet excited state), and k n represents the rate constant of the non-emission process (heat deactivation or intersystem crossing) of the first material, and τ represents the measured lifetime of the excited state of the first material.

[0120]

Equation

[0121] From Equation (3), it can be seen that to increase the energy transfer efficiency φ ET , the rate constant k of energy transfer should be increased, and the other competing rate constant k h*→g + k r + k n (= 1 / τ) should be relatively small.

[0122] ≪Concepts for enhancing energy transfer≫ First, consider energy transfer by the Förster mechanism. By substituting Equation (1) into Equation (3), τ can be eliminated. Therefore, in the case of the Förster mechanism, the energy transfer efficiency φ does not depend on the lifetime τ of the excited state of the first material. Also, the energy ET transfer efficiency φ does not depend on the lifetime τ of the excited state of the first material. Also, the energy ET transfer efficiency φ is the fluorescence quantum yield, and when discussing energy transfer from the triplet excited state, it can be said that the phosphorescence quantum yield) should be higher.

[0123] In addition, the emission spectrum of the first material (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 second material (absorption corresponding to the transition from the singlet ground state to the singlet excited state should preferably have a large overlap. Furthermore, it is preferable that the molar extinction coefficient of the second material is also high. This means that the emission spectrum of the first material overlaps with the absorption band that appears on the longest wavelength side of the second material. Note that since the direct transition from the singlet ground state to the triplet excited state in the second material is forbidden, the molar extinction coefficient related to the triplet excited state in the second material is an ignorable amount. From this, the energy transfer process from the excited state of the first material to the triplet excited state of the second material by the Förster mechanism can be ignored and only the energy transfer process to the singlet excited state of the second material needs to be considered.

[0124] Next, consider the energy transfer by the Dexter mechanism. According to Equation (2), to increase the rate constant k h*→g it can be seen that it is better for the emission spectrum of the first material (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 second material (absorption corresponding to the transition from the singlet ground state to the singlet excited state to have a large overlap. Therefore, the optimization of the energy transfer efficiency is related to the emission spectrum of the first material and the longest wavelength of the second material It is realized by overlapping with the absorption band appearing on the long side.

[0125] Also, substituting Equation (2) into Equation (3), the energy transfer in the Dexter mechanism efficiency φ ET is found to depend on τ. The Dexter mechanism is an energy transfer process based on electron exchange. Therefore, similar to the energy transfer from the singlet excited state of the first material to the singlet excited state of the second material, energy transfer from the triplet excited state of the first material to the triplet excited state of the second material also occurs.

[0126] In addition, similar to the energy transfer from the first material to the second material, for the energy transfer process from the exciplex to the fluorescent compound, energy transfer by both the Förster mechanism and the Dexter mechanism occurs.

[0127] In the light-emitting device according to one aspect of the present invention, since the second material is a fluorescent compound, it is preferable that the energy transfer efficiency to the triplet excited state of the second material is low. That is, it is preferable that the energy transfer efficiency based on the Dexter mechanism from the first material to the second material is low, and it is preferable that the energy transfer efficiency based on the Förster mechanism from the first material to the second material is high.

[0128] Also, as already described, the energy transfer efficiency in the Förster mechanism does not depend on the lifetime τ of the excited state of the first material. On the other hand, the energy transfer efficiency in the Dexter mechanism depends on the excitation lifetime τ of the first material. In order to lower the energy transfer efficiency in the Dexter mechanism, it is preferable that the excitation lifetime τ of the first material is short.

[0129] Therefore, one aspect of the present invention uses an exciplex or a TADF material as the first material, and one of the compounds forming the exciplex has a function of converting triplet excitation energy into light emission. According to the configuration of one aspect of the present invention, reverse intersystem crossing from the triplet excited state to the singlet excited state of the exciplex (first material) is promoted, and the excitation lifetime τ of the triplet excited state of the exciplex (first material) can be shortened. Further, the transition from the triplet excited state of the exciplex (first material) to the ground state is promoted, and the excitation lifetime τ of the triplet excited state of the exciplex (first material) can be shortened. As a result, the energy transfer efficiency in the Dexter mechanism from the triplet excited state of the exciplex (first material) to the fluorescent compound (second material) can be reduced. Therefore, in one aspect of the present invention, a light-emitting device with high luminous efficiency can be provided.

[0130]

[0131] Among the light emissions exhibited by the exciplex, the fluorescence lifetime in the thermally activated delayed fluorescence component is preferably short, specifically, preferably 10 ns or more and 50 μs or less, more preferably 10 ns or more and 20 μs or less, still more preferably 10 ns or more and 10 μs or less. The rate constant of the Förster mechanism is inversely proportional to the sixth power of the distance between the first material and the second material, and the rate constant of the Dexter mechanism is inversely proportional to the exponential function of the distance between the first material and the second material. Therefore, when the distance between the two molecules is approximately 1 nm or less, the Dexter mechanism becomes dominant, and when it is approximately 1 nm or more, the Förster mechanism becomes dominant. Therefore, in order to reduce the energy transfer efficiency in the Dexter mechanism, the distance between the first material and the second material should be increased. ​​It is preferable to do so. Specifically, it is preferably 0.7 nm or more, more preferably 0.9 n m or more, still more preferably 1 nm or more. Also, for the Förster mechanism to occur efficiently, the distance between the first material and the second material is preferably 5 nm or less.

[0132] Therefore, in one aspect of the present invention, compound 133, which is a fluorescent compound, preferably has at least two or more alkyl groups having 2 or more carbon atoms. Alternatively, compound 133 preferably has at least two or more alkyl groups having a branch with 3 to 10 carbon atoms . Alternatively, compound 133 preferably has at least two or more cyclic hydrocarbon groups having 3 to 10 carbon atoms, or at least two or more bridged cyclic hydrocarbon groups having 3 to 10 carbon atoms . Further, compound 133 preferably has a condensed aromatic hydrocarbon having 3 to 12 carbon atoms .

[0133]

[0134] <Material> Next, the details of the components of the light-emitting element according to one aspect of the present invention will be described below.

[0134] ≪Light-emitting layer≫ The materials that can be used for the light-emitting layer 130 will be described below, respectively.

[0135] Compound 132 is an organic compound having a benzofuropyrimidine skeleton or a benzothienopyrimidine skeleton. The organic compound has good electron-transporting properties and a high T1 level, so it can be suitably used as a host material for the light-emitting layer.

[0136] The above-mentioned benzofuropyrimidine skeleton or benzothienopyrimidine skeleton is preferably a benzofuro[3, 2-d]pyrimidine skeleton or a benzothieno[3,2-d]pyrimidine skeleton​ Furthermore, it is more preferable that the benzofuro[3,2-d]pyrimidine skeleton or the benzothieno[3,2-d]pyrimidine skeleton has substituents at the 4-position and / or the 8-position. By adopting such a configuration, a light-emitting element with good luminous efficiency and further good reliability can be obtained.

[0137] In addition, examples of the compound having the above-mentioned benzofuropyrimidine skeleton or benzothienopyrimidine skeleton include organic compounds having a naphthofuropyrimidinyl group or a naphthothienopyrimidinyl group. Organic compounds having a naphthofuropyrimidinyl group or a naphthothienopyrimidinyl group have good reliability and can be suitably used for the light-emitting element according to one aspect of the present invention.

[0138] Examples of the above-mentioned benzofuropyrimidine skeleton or benzothienopyrimidine skeleton include skeletons represented by the following general formulas (101) to (114). In the general formulas (101) to (114), X represents an oxygen atom or a sulfur atom, Ht and Ht each independently represents hydrogen or any one of (Ht-1) to (Ht-13) described later, and 1 Ht 2 and each independently represents hydrogen or any one of (Ht-1) to (Ht-13) described later, Ar and Ar 1 each independently represents hydrogen or any one of (Ar-1) to (Ar-27 2 ) described later. However, the organic compound having a benzofuropyrimidine skeleton or a benzothienopyrimidine skeleton that can be used in one aspect of the present invention is not limited to the following examples.

[0139]

Chemical Formula

[0140] ​In addition, as the substituent bonded to the 4-position and / or 8-position of the above benzofuro[3,2-d]pyrimidine skeleton or benzothieno[3,2-d]pyrimidine skeleton, a substituent having a π-electron-excessive heteroaromatic skeleton represented by Ht in the general formulas (101) to (114) is preferable. As the skeleton, a furan skeleton, a thiophene skeleton, and a pyrrole skeleton are preferable because they are stable and have good reliability. More preferably, a carbazole skeleton, a dibenzofuran skeleton, and a dibenzothiophene skeleton are included. By adopting such a configuration, a light-emitting element with excellent reliability can be obtained. As the above π-electron-excessive heteroaromatic skeleton, for example, skeletons represented by the following general formulas (Ht-1) to (Ht-13) are included. In the general formulas (Ht-1) to (Ht-13 ), X represents an oxygen atom or a sulfur atom.

[0141] The general formulas (101) to (114) and the general formulas (Ht-1) to (Ht-13) may have substituents. As the substituents, 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 12 carbon atoms can be selected as substituents. Specific examples of the alkyl group having 1 to 6 carbon atoms include, for example, 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, for example, The above π-electron-excessive heteroaromatic skeleton, for example, skeletons represented by the following general formulas (Ht-1) to X in (Ht-13) represents an oxygen atom or a sulfur atom.

[0142]

Chemical formula

[0143] The general formulas (101) to (114) and the general formulas (Ht-1) to (Ht-13) may have substituents. As the substituents, 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 12 carbon atoms can be selected as substituents. Specific examples of the alkyl group having 1 to 6 carbon atoms include, for example, 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, for example, The general formulas (101) to (114) and the general formulas (Ht-1) to (Ht-13) may have substituents. As the substituents, 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 12 carbon atoms can be selected as substituents. Specific examples of the alkyl group having 1 to 6 carbon atoms include, for example, 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, for example, The general formulas (101) to (114) and the general formulas (Ht-1) to (Ht-13) may have substituents. As the substituents, 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 12 carbon atoms can be selected as substituents. Specific examples of the alkyl group having 1 to 6 carbon atoms include, for example, 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, for example, The general formulas (101) to (114) and the general formulas (Ht-1) to (Ht-13) may have substituents. As the substituents, 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 12 carbon atoms can be selected as substituents. Specific examples of the alkyl group having 1 to 6 carbon atoms include, for example, 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, for example, The general formulas (101) to (114) and the general formulas (Ht-1) to (Ht-13) may have substituents. As the substituents, 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 12 carbon atoms can be selected as substituents. Specific examples of the alkyl group having 1 to 6 carbon atoms include, for example, 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, for example, The general formulas (101) to (114) and the general formulas (Ht-1) to (Ht-13) may have substituents. As the substituents, 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 12 carbon atoms can be selected as substituents. Specific examples of the alkyl group having 1 to 6 carbon atoms include, for example, 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, for example, The general formulas (101) to (114) and the general formulas (Ht-1) to (Ht-13) may have substituents. As the substituents, 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 12 carbon atoms can be selected as substituents. Specific examples of the alkyl group having 1 to 6 carbon atoms include, for example, 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, for example, Examples include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. Examples of the aryl group having 6 to 12 carbon atoms include, for example, phenyl group, naphthyl group, biphenyl group, and the like. Further, the above substituents may be bonded to each other to form a ring. As such an example, for example, when the 9-position carbon in the fluorene skeleton has two phenyl groups as substituents, a case where the phenyl groups are bonded to each other to form a spirofluorene skeleton may be mentioned. In addition, in the case of no substitution, it is advantageous in terms of ease of synthesis and raw material price.

[0144] Further, in general formulas (101) to (114), the substituents represented by Ar 1 and Ar 2 include each independently hydrogen or a substituted or unsubstituted aryl group having 6 to 25 carbon atoms. Examples of the aryl group having 6 to 25 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a terphenyl group, a fluorenyl group, and the like. More specifically, groups represented by the following structural formulas (Ar -28) to (Ar-46) may be mentioned. Note that the substituents represented by Ar and Ar 1 and Ar 2 are not limited to these.

[0145]

Chemical formula

[0146] Further, in general formulas (Ht-2), (Ht-5), (Ht-8), and (Ht-11) to (Ht -13), Ar represents a single bond or an arylene group having 6 to 25 carbon atoms, and the aryl The arylene group may have a substituent, and the substituents may be bonded to each other to form a ring. As such an example, for example, the carbon at the 9-position of the fluorenyl group has two phenyl groups as substituents and the phenyl groups are bonded to each other to form a spirofluorene skeleton. Such a case can be mentioned. Examples of the arylene group having 6 to 25 carbon atoms include, for example , a phenylene group, a naphthalenediyl group, a biphenyldiyl group, a fluorenediyl group, etc. can be specifically mentioned as examples. When the arylene 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 an aryl group having 6 to 12 carbon atoms as a substituent. Specific examples of the alkyl group having 1 to 6 carbon atoms include, for example, 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, specific examples of the cycloalkyl group having 3 to 6 carbon atoms include, for example, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, etc. Further, specific examples of the aryl group having 6 to 12 carbon atoms include, for example, a phenyl group, a naphthyl group, a biphenyl group, etc. can be mentioned as specific examples.

[0147] In addition, as the arylene group represented by Ar, for example, groups represented by the following structural formulas (Ar-1) to (Ar- 27) can be applied. Note that the groups that can be used as Ar are not limited to these.

[0148]

Chemical formula

[0149] Also, in general formulas (Ht-3), (Ht-6), and (Ht-9), R 1 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, for example, a methyl group, an ethyl group, a propyl group, an iso propyl 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 , for example, 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, for example , a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, and the like. Furthermore, the above-described aryl group or phenyl 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 12 carbon atoms. Specific examples of the alkyl group having 1 to 6 carbon atoms include, for example, 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, for example, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and the like. Specific examples of the aryl group having 6 to 12 carbon atoms include, for example, a phenyl group, and the like. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include, for example, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and the like. Specific examples of the aryl group having 6 to 12 carbon atoms include, for example, a phenyl group, and the like. Specific examples thereof include a naphthyl group, a biphenyl group, and the like.

[0150] In addition, the alkyl group or aryl group represented by R 1 can be, for example, a group represented by the following structural formula (R-1) to (R-32). Note that the groups that can be used as the alkyl group or aryl group are not limited to these. are not limited to these.

[0151]

Chemical formula

[0152] In addition, the substituents that the general formulas (101) to (114), the general formulas (Ht-1) to (Ht-13), and Ar and R 1 can have can be, for example, an alkyl group or aryl group represented by the above structural formulas (R-1) to (R- 32). Note that the groups that can be used as the alkyl group or aryl group are not limited to these. are not limited to these.

[0153] As described above, as Compound 131, it preferably has a function of converting triplet excitation energy into light emission. Examples of the organic compound having such a function include a phosphorescent material and a thermally activated delayed fluorescence material. Examples of the phosphorescent compound include an iridium, rhodium, or platinum-based organometallic complex, or a metal complex. In addition, a platinum complex having a porphyrin ligand and an organoiridium complex are included. Among them, for example, an organoiridium complex such as an iridium-based orthometal complex is preferred. Examples of the ligand for orthometalation include a 4H-triazole ligand, a 1H-triazole ligand, an imidazole ligand, a pyridine ligand, a pyrimidine ligand, and a pyrazine ligand. are included. Among them, for example, an organoiridium complex such as an iridium-based orthometal complex is preferred. Examples of the ligand for orthometalation include a 4H-triazole ligand, a 1H-triazole ligand, an imidazole ligand, a pyridine ligand, a pyrimidine ligand, and a pyrazine ligand.

[0154] Examples of the phosphorescent compound include an iridium, rhodium, or platinum-based organometallic complex, or a metal complex. In addition, a platinum complex having a porphyrin ligand and an organoiridium complex are included. Among them, for example, an organoiridium complex such as an iridium-based orthometal complex is preferred. Examples of the ligand for orthometalation include a 4H-triazole ligand, a 1H-triazole ligand, an imidazole ligand, a pyridine ligand, a pyrimidine ligand, and a pyrazine ligand. Examples of the phosphorescent compound include an iridium, rhodium, or platinum-based organometallic complex, or a metal complex. In addition, a platinum complex having a porphyrin ligand and an organoiridium complex are included. Among them, for example, an organoiridium complex such as an iridium-based orthometal complex is preferred. Examples of the ligand for orthometalation include a 4H-triazole ligand, a 1H-triazole ligand, an imidazole ligand, a pyridine ligand, a pyrimidine ligand, and a pyrazine ligand. Examples of the phosphorescent compound include an iridium, rhodium, or platinum-based organometallic complex, or a metal complex. In addition, a platinum complex having a porphyrin ligand and an organoiridium complex are included. Among them, for example, an organoiridium complex such as an iridium-based orthometal complex is preferred. Examples of the ligand for orthometalation include a 4H-triazole ligand, a 1H-triazole ligand, an imidazole ligand, a pyridine ligand, a pyrimidine ligand, and a pyrazine ligand. Examples of the ligand for orthometalation include a 4H-triazole ligand, a 1H-triazole ligand, an imidazole ligand, a pyridine ligand, a pyrimidine ligand, and a pyrazine ligand. Examples of the ligand for orthometalation include a 4H-triazole ligand, a 1H-triazole ligand, an imidazole ligand, a pyridine ligand, a pyrimidine ligand, and a pyrazine ligand. Examples include a position or an isoquinoline ligand. In this case, compound 131 (a phosphorescent compound) has an absorption band for a triplet MLCT (Metal to Ligand Charge Tran sfer) transition.

[0155] Examples of substances having an emission peak in blue or green include, for example, tris{2-[5-(2 -methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazolo -3-yl-κN 2 phenyl-κC}iridium(III) (abbreviation: Ir(mpp tz-dmp)3), tris(5-methyl-3,4-diphenyl-4H-1,2,4-tri azolato)iridium(III) (abbreviation: Ir(Mptz)3), tris[4-(3- biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]ir idium(III) (abbreviation: Ir(iPrptz-3b)3), tris[3-(5-bip enyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]iridium (III) (abbreviation: Ir(iPr5btz)3), such as organometallic iridium complexes having a 4H-triazole skeleton and 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-triazolato)iridium(III) (abbreviation: Ir(Prptz1-Me) 3), such as organometallic iridium complexes having a 1H-triazole skeleton, and fac-tris [1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]ir 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’ ]Ili Dium(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis (Trifluoromethyl)phenyl]pyridinato-N,C 2’}Iridium(III) pico Ir(CF3ppy)2(pic) (fluorophenyl)pyridinato-N,C 2’ ]Iridium(III) acetylacetonate (abbreviation: FIr(acac)) Among the above, 4H-triazole is an organometallic iridium complex. Nitrogen-containing five-membered heterocyclic skeletons such as 1H-triazole skeleton and imidazole skeleton The organometallic iridium complex has high triplet excitation energy and is highly reliable and has excellent luminescence efficiency. It is particularly preferred because it is also excellent in

[0156] In addition, examples of substances having a green or yellow emission peak include tris(4-methylphenyl) Ir(mppm)3, Tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: I r(tBuppm)3), (acetylacetonato)bis(6-methyl-4-phenylpyr midinato)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-norbornyl)-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-κN 3 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)iridium (III) (abbreviation: Ir(bzq)3), tris(2-phenylquinolinato-N,C 2 ’ )iridium(III) (abbreviation: Ir(pq)3), bis(2-phenylquinolinato- N,C 2’ )iridium(III) acetylacetonate (abbreviation: Ir(pq)2(ac ac)) and other organometallic iridium complexes having a pyridine skeleton, bis(2,4-dif enyl-1,3-oxazolato-N,C 2’ )iridium(III) acetylacetonate (abbreviation: Ir(dpo)2(acac)), bis{2-[4’-(perfluorophenyl l)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 rare earth metal complexes can be mentioned. Among the above, organometallic iri dium complexes having a pyrimidine skeleton are particularly preferred because they are outstanding in reliability and luminescence efficiency.

[0157] In addition, 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 ato](dipivaloylmethanato)iridium(III) (abbreviation: Ir(d1npm)2( dpm)) and other organometallic iridium complexes having a pyrimidine skeleton, (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)) and other organometallic iridium complexes having a pyrazine skeleton, 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)) and other organometallic iridium complexes having a pyridine skeleton, in addition to 2,3,7, 8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II )(abbreviation: PtOEP) and other platinum complexes, tris(1,3-diphenyl-1,3-prop anedionato)(monophenanthroline)europium(III) (abbreviation: Eu(DB M)3(Phen)), tris[1-(2-thenoyl)-3,3,3-trifluoroacet tonato](monophenanthroline)europium(III) (abbreviation: Eu(TTA)3( Phen)) and the like. Among those described above, organometallic iridium complexes having a pyrimidine skeleton are particularly preferable because they are remarkably excellent in reliability and luminescence efficiency. In addition, an organometallic iridium complex having a pyrazine skeleton can obtain red luminescence with good chromaticity.

[0158] In addition, as the material that can be used as Compound 131, as described above, thermally activated delayed fluorescence materials can be mentioned. Specifically, the following materials can be used.

[0159] 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(E tio I)), octaethylporphyrin-platinum chloride complex (PtCl2OEP), etc.

[0160] ​​​​​​​​​​​​​ In addition, as a thermally activated delayed fluorescence material composed of a single type of material, a heterocyclic compound having a π-electron rich heteroaromatic ring and a π-electron deficient 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-phenoxazin-10-yl)phenyl]-4, 6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-xanthen-9-one (abbreviation: ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10’H-spiro[acridine-9,9’-anthracene]-10’-one (abbreviation: ACRSA), etc. can be mentioned. Since the heterocyclic compound has a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring, it has high electron transportability and hole transportability, 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 triazine skeleton is preferable because it is stable and has good reliability. In addition, for the π-electron rich heteroaromatic ring, Among the skeletons, the acridine skeleton, the phenoxazine skeleton, the thiophene skeleton, the furan skeleton, and the pyrrole skeleton are stable and have good reliability. Therefore, it is preferable to have any one or more selected from 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. In addition, a substance in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded has both strong donor properties of the π-electron-rich heteroaromatic ring and acceptor properties of the π-electron-deficient heteroaromatic ring, and the energy level difference between the singlet excited state energy level and the triplet excited state energy level is small. Therefore, it is particularly preferable. Among these, it is preferable to have any one or more selected from these skeletons because they are stable and have good reliability. As for the pyrrole skeleton, an indole skeleton, a carbazole skeleton, and a 3-(9-phenyl-9H-carbazol-3-yl)-9H-carbazole skeleton are particularly preferable. 9H-carbazole skeleton are particularly preferred. In addition, a substance in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded has both strong donor properties of the π-electron-rich heteroaromatic ring and acceptor properties of the π-electron-deficient heteroaromatic ring, and the energy level difference between the singlet excited state energy level and the triplet excited state energy level is small. Therefore, it is particularly preferable. In addition, a substance in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded has both strong donor properties of the π-electron-rich heteroaromatic ring and acceptor properties of the π-electron-deficient heteroaromatic ring, and the energy level difference between the singlet excited state energy level and the triplet excited state energy level is small. Therefore, it is particularly preferable. Therefore, it is particularly preferable. Therefore, it is particularly preferable.

[0161] In addition, as the compound 133 in the light-emitting layer 130, a fluorescent compound is preferable. The fluorescent compound is not particularly limited, but an anthracene derivative, a tetracene derivative, a chrysene derivative, a phenanthrene derivative, a pyrene derivative, a perylene derivative, a stilbene derivative, an acridone derivative, a coumarin derivative, a phenoxazine derivative, a phenothiazine derivative, etc. are preferable. The fluorescent compound is not particularly limited, but an anthracene derivative, a tetracene derivative, a chrysene derivative, a phenanthrene derivative, a pyrene derivative, a perylene derivative, a stilbene derivative, an acridone derivative, a coumarin derivative, a phenoxazine derivative, a phenothiazine derivative, etc. are preferable. derivative, a phenanthrene derivative, a pyrene derivative, a perylene derivative, a stilbene derivative, an acridone derivative, a coumarin derivative, a phenoxazine derivative, a phenothiazine derivative, etc. are preferable. derivative, a coumarin (coumarin) derivative, a phenoxazine derivative, a phenothiazine derivative, etc. are preferable. etc. are preferable.

[0162] 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 rene-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-dia mine (abbreviation: 1,6tBu-FLPAPrn), N,N'-bis[4-(9-phenyl- 9H-fluoren-9-yl)phenyl]-N,N'-diphenyl-3,8-dicyclohe xylpyrene-1,6-diamine (abbreviation: ch-1,6FLPAPrn), N,N'-bi s[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene -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)f -9H-carbazol-3-amine (abbreviation: 2PCAPPA), N-[4-(9 ,10-diphenyl-2-anthryl)phenyl]-N,N’,N’-triphenyl-1 ,4-phenylenediamine (abbreviation: 2DPAPPA), N,N,N’,N’,N’’,N ’’,N’’’,N’’’-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-triphen ylanthracen-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-diphen yltetracene (abbreviation: TBRb), Nile Red, 5,12-bis(1,1’-biphen Ru-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-yl idene)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}pro panedinitrile (abbreviation: BisDCJTM), 5,10,15,20-tetraphenyl Bisbenzo[5,6]indeno[1,2,3-cd:1’,2’,3’-lm]perylene and the like.

[0163] When an exciplex is formed between Compound 131 and Compound 132, the emission peak of the formed exciplex is preferably selected for Compound 131, Compound 132, and Compound 133 so as to overlap with the absorption band on the longest wavelength side (low energy side) of the light-emitting material, Compound 133. Thereby, a light-emitting device with a dramatically improved luminous efficiency can be obtained.

[0164] 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 stacked 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.

[0165] Also, as shown in FIG. 4, in the light-emitting layer 130, it may contain a material (Compound 134) other than Compound 131, Compound 132, and Compound 133. In that case, it is preferable that an exciplex is formed between Compound 132 and Compound 134. To achieve such a configuration, one of the HOMO levels of Compound 132 and Compound 134 has the highest HO MO level among the materials in the light-emitting layer 130, and the other LUMO level has the lowest LUMO level among the materials in the light-emitting layer 130. That is, it is preferable that one of the HOMO levels of Compound 132 and Compound 134 is higher than the other HOMO level and the HOMO level of Compound 131, and the other LUMO level is lower than one of the LUMO levels and the LUMO level of Compound 131. The By being configured in this way, the reaction of forming an exciplex between Compound 132 and Compound 131 can be suppressed. This can be achieved.

[0166] As Compound 134, for example, the following hole transporting materials and electron transporting materials can be used. However, as described above, since Compound 132 has a benzofuropyrimidine skeleton or a benzothienopyrimidine skeleton, it is a compound with a low LUMO level and good electron transporting properties. Therefore, it is preferable that Compound 134 is an organic compound (hole transporting material) having a HOMO level higher than that of Compound 132 and good hole transporting properties. 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 cm

[0167] / Vs or more. Specifically, aromatic amines, carbazole derivatives, etc. can be used. Further, the hole transporting material may be a polymer compound. ×10 -6 cm 2 / Vs or more. Specifically, aromatic amines, carbazole derivatives, etc. can be used. Further, the hole transporting material may be a polymer compound. As these materials with high hole transporting properties, for example, as aromatic amine compounds, N,N’-di(p-tolyl)-N,N’-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4’-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N’-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N’-diphenyl-(1,1’-biphenyl)-4,4’-diamine (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), etc. can be mentioned. As these materials with high hole transporting properties, for example, as aromatic amine compounds, N,N’-di(p-tolyl)-N,N’-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4’-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N’-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N’-diphenyl-(1,1’-biphenyl)-4,4’-diamine (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), etc. can be mentioned.

[0168] As these materials with high hole transporting properties, for example, as aromatic amine compounds, N,N’-di(p-tolyl)-N,N’-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4’-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N’-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N’-diphenyl-(1,1’-biphenyl)-4,4’-diamine (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), etc. can be mentioned. -di(p-tolyl)-N,N’-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4’-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N’-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N’-diphenyl-(1,1’-biphenyl)-4,4’-diamine (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), etc. can be mentioned. PA), 4,4’-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N’-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N’-diphenyl-(1,1’-biphenyl)-4,4’-diamine (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), etc. can be mentioned. biphenyl (abbreviation: DPAB), N,N’-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N’-diphenyl-(1,1’-biphenyl)-4,4’-diamine (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), etc. can be mentioned. 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. amine (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), etc. can be mentioned. amine (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), etc. can be mentioned.

[0169] Also, as the carbazole derivative, 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 lamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N- (9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarb azole (abbreviation: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarb azole-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1) etc. can be mentioned.

[0170] Also, as the carbazole derivative, among others, 4,4'-di(N-carbazolyl)biphe nyl (abbreviation: CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]ben zene (abbreviation: TCPB), 1,4-bis[4-(N-carbazolyl)phenyl]-2,3 ,5,6-tetraphenylbenzene etc. can be used.

[0171] Also, as the material with high hole transport property, for example, 4,4'-bis[N-(1-naphthyl )-N-phenylamino]biphenyl (abbreviation: NPB or α-NPD) or N,N'-bi (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-naphthyl )-N-phenylamino]triphenylamine (abbreviation: 1'-TNATA), 4,4' ,4''-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA ), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino]tri phenylamine (abbreviation: m-MTDATA), 4,4'-bis[N-(spiro-9,9 '-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation : BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)tri phenylamine (abbreviation: mBPAFLP), N-(9,9-dimethyl-9H-fluorene- 2-yl)-N-{9,9-dimethyl-2-[N'-phenyl-N'-(9,9-dimethyl yl-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-dip enylaminophenyl)-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: PCBBi1 BP), 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: PCB NBB), 4-phenyldiphenyl-(9-phenyl-9H-carbazol-3-yl) amine (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)benzene-1,3,5-triamine (abbreviation: PCA3B), N-(4-biphenyl )-N-(9,9-dimethyl-9H-fluorene-2-yl)-9-phenyl-9H-ca rbazole-3-amine (abbreviation: PCBiF), N-(1,1'-biphenyl-4-yl )-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9- dimethyl-9H-fluorene-2-amine (abbreviation: PCBBiF), 9,9-dimethyl- N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl] fluorene-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-pheni l-9H-carbazol-3-yl)phenyl]spiro-9,9'-bifluorene-2- amine (abbreviation: PCBASF), 2-[N-(9-phenylcarbazol-3-yl)- N-phenylamino]spiro-9,9'-bifluorene (abbreviation: PCASF), 2,7- bis[N-(4-diphenylaminophenyl)-N-phenylamino]spiro-9,9' -bifluorene (abbreviation: DPA2SF), N-[4-(9H-carbazol-9-yl) -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 L-9H-carbazole (abbreviation: PCPN), 3-[4-(9-phenanthryl)phenyl L]-9-phenyl-9H-carbazole (abbreviation: PCPPn), 3,3'-bis(9 -Phenyl-9H-carbazole) (abbreviation: PCCP), 1,3-bis(N-carbazolyl L)benzene (abbreviation: mCP), 3,6-bis(3,5-diphenylphenyl)-9-phenyl Lcarbazole (abbreviation: CzTP), 4-{3-[3-(9-phenyl-9H-fluoren -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)benz ene (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl- 9H-fluorene-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-I II), 4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]-6-phenyl Ldibenzothiophene (abbreviation: DBTFLP-IV), 4-[3-(triphenylene -2-yl)phenyl]dibenzothiophene (abbreviation: mDBTPTp-II) and other amine compounds, carbazole compounds, thiophene compounds, furan compounds, fluorene compounds, trip henylenylene compounds, phenanthrene compounds, etc. can be used. The substances described here​ is a substance having a hole mobility of mainly 1×10 -6 cm 2 / Vs or more. However, as long as it is a substance with higher hole transportability than electrons, substances other than these may be used.

[0172] ≪Pair of electrodes≫ The electrodes 101 and 102 have the function of injecting holes and electrons into the light-emitting layer 130. The electrodes 101 and 102 can be formed using metals, alloys, conductive compounds, and mixtures or laminates thereof. Aluminum (Al) is a typical example of a metal, and other transition metals such as silver (Ag), tungsten, chromium, molybdenum, copper, and titanium , alkali metals such as lithium (Li) and cesium, and group 2 metals such as calcium and magnesium (Mg) can be used. Rare earth metals such as ytterbium (Yb) can also be used as transition metals. As alloys, alloys containing the above metals can be used, and examples include MgAg and AlLi. Examples of conductive compounds include indium tin oxide (Indium Tin Oxide, hereinafter ITO), indium tin oxide containing silicon or silicon oxide (abbreviation: ITSO), indium zinc oxide (Indium Z inc Oxide), and metal oxides such as indium oxide containing tungsten and zinc. Inorganic carbon-based materials such as graphene can also be used as conductive compounds. As described above, one or both of the electrodes 101 and 10 2 can be formed by laminating a plurality of these materials.

[0173] Also, the light emitted from the light-emitting layer 130 is one or both of the electrodes 101 and 102 ​It is taken out through. Therefore, at least one of the electrode 101 and the electrode 102 is visible It has a function of transmitting light. As the conductive material having a function of transmitting light, the visible light transmittance is 40% or more and 100% or less, preferably 60% or more and 100% or less, and its resistance is 1×10 -2 Ω·cm or less. In addition, the electrode on the light extraction side 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 4 0% or more and 70% or less, and its resistivity is 1×10 Ω·cm or less. When a material with low light transmittance such as metal or alloy is used for the electrode on the light extraction side -2 one or both of the electrode 101 and the electrode 102 may be formed with a thickness that allows visible light to pass through (for example, a thickness of 1 nm to 10 nm). In addition, in this specification and the like, for the electrode having a function of transmitting light, a material having a function of transmitting visible light and having conductivity may be used. For example, in addition to the oxide conductor layer typified by ITO as described above, it includes an oxide semiconductor layer or an organic conductor layer containing an organic substance. Examples of the organic conductor layer containing an organic substance include a layer containing a composite material formed by mixing an organic compound and an electron donor (donor), a layer containing a composite material formed by mixing an organic compound and an electron acceptor (acceptor), and the like. In addition, the resistivity of the transparent conductive layer is preferably

[0174] 1×10 Ω·cm or less, more preferably 1×10 Ω·cm or less. In addition, as the organic conductor layer containing an organic substance, for example, a layer containing a composite material formed by mixing an organic compound and an electron donor (donor), a layer containing a composite material formed by mixing an organic compound and an electron acceptor (acceptor), and the like can be mentioned. Further, the resistivity of the transparent conductive layer is preferably 1×10 Ω·cm or less, more preferably 1×10 5 Ω·cm or less, and even more preferably 1×10 4 Ω·cm or less.

[0175] The electrode 101 and the electrode 102 may be formed by a sputtering method, a vapor deposition method, a printing method, or the like. Coating method, MBE (Molecular Beam Epitaxy) method, CVD (Chemical Vapor Deposition) method Phase Growth, Pulsed Laser Deposition, ALD (Atomic Layer Deposit) The ion method and the like can be appropriately used.

[0176] <Hole injection layer> The hole injection layer 111 is configured to inject holes from one of the pair of electrodes (electrode 101 or electrode 102). It has the function of promoting hole injection by reducing the injection barrier. It is formed by phthalocyanine derivatives or aromatic amines. Transition metal oxides and Examples include molybdenum oxide, vanadium oxide, ruthenium oxide, and tungsten oxide. , manganese oxide, etc. Phthalocyanine derivatives include phthalocyanine, Examples of aromatic amines include benzidine derivatives and phenyl Diamine derivatives, etc. Polymer compounds such as polythiophene and polyaniline It is also possible to use self-doped polythiophenes, such as poly(ethylenediamine). Representative examples include poly(oxythiophene) / poly(styrenesulfonic acid).

[0177] The hole injection layer 111 is made of a compound of a hole transporting material and a material that has an electron accepting property. Alternatively, a layer containing a material exhibiting electron accepting properties and a layer containing a positive electrode may be used. A stack of layers containing hole transporting materials may also be used. It is possible to give and receive charges in the presence of a magnetic field. Materials that exhibit electron-accepting properties include quinodimethane. Organic acceptors such as aryl, chloranil, and hexaazatriphenylene derivatives Specifically, 7,7,8,8-tetracyano-2,3,5,6- Tetrafluoroquinodimethane (abbreviation: F4-TCNQ), chloranil, 2,3,6,7, 10,11-Hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation These are compounds that have electron-withdrawing groups (halogen groups or cyano groups) such as aryloxycarbonyl (HAT-CN). In addition, transition metal oxides, for example oxides of metals in Groups 4 to 8, can be used. In particular, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, and oxide These include tungsten oxide, manganese oxide, and rhenium oxide. Among these, molybdenum oxide is Among these, it is preferred because it is stable, has low hygroscopicity, and is easy to handle.

[0178] As the hole transporting material, a material having a higher hole transporting property than an electron transporting property can be used. ×10 -6 cm 2 It is preferable that the material has a hole mobility of 1 / Vs or more. The aromatic amines and the like listed as hole transporting materials that can be used in the light emitting layer 130 are Carbazole derivatives can be used. Aromatic hydrocarbons and stilbene derivatives can also be used. The hole transporting material may be a polymer compound.

[0179] Examples of aromatic hydrocarbons include 2-tert-butyl-9,10-di(2-naphthyl) 2-tert-butyl-9,10-di(1 -naphthyl)anthracene, 9,10-bis(3,5-diphenylphenyl)anthracene DPPA, 2-tert-butyl-9,10-bis(4-phenylphenyl) Anthracene (abbreviation: t-BuDBA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 9,10-diphenylanthracene (abbreviation: DPAnth), 2-t ert-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-naph thyl)phenyl]anthracene, 2,3,6,7-tetramethyl-9,10-di(1-naph thyl)anthracene, 2,3,6,7-tetramethyl-9,10-di(2-naphthyl) anthracene, 9,9’-bianthryl, 10,10’-diphenyl-9,9’-bian thryl, 10,10’-bis(2-phenylphenyl)-9,9’-bianthryl, 10 ,10’-bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9’-bia nthryl, 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, it is more preferable to use an aromatic hydrocarbon having a hole mobility of 1×10 -6 cm 2 / Vs or more and having 14 or more and 42 or less carbon atoms. Furthermore, 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

[0180] (abbreviation: DPVBi), 9,10-bis[4-(2,2-diphenylvinyl)phenyl] anthracene (abbreviation: DPVPA), etc. (abbreviation: DPVBi), 9,10-bis[4-(2,2-diphenylvinyl)phenyl] anthracene (abbreviation: DPVPA), etc.

[0181] In addition, high molecular compounds such as poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N’-[4-(4-diphenylamino)phenyl]phenyl-N’-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA), poly[N,N’-bis(4-butylphenyl)-N,N’-bis(phenyl)benzidine] (abbreviation: Poly-TPD), etc. can also be used.

[0182] ≪Hole transport layer≫ The hole transport layer 112 is a layer containing a hole transporting material, and the 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 that of the hole injection layer 111.

[0183] As the above hole transporting material, the materials exemplified as the material of the hole injection layer 111 can be used. 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 transportability than electrons, other substances may be used. Note that the layer containing a substance with high hole transportability may be not only a single layer, but also two or more layers of the above substances laminated.

[0184] ≪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. The electron transporting material ​As for this, a material with higher electron transport property than hole can be used, and it is preferably a material having an electron mobility of 1×10 -6 cm 2 / Vs or more. As a compound (material having electron transport property) that easily accepts electrons, a π-electron deficient heteroaromatic such as a nitrogen-containing heteroaromatic compound or a metal complex can be used. In particular, it is preferably an organic compound having a benzofuropyrimidine skeleton or a benzothienopyrimidine skeleton. Other specific examples include metal complexes having a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand. In addition, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives and the like can be mentioned. Note that as long as it is a substance having higher electron transport property than hole, substances other than the above can 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 layers made of the above-mentioned substances laminated.

[0185] Specific examples of the electron transport material include 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-phenylphen enolato)aluminum(III)(abbreviation: BAlq), bis(8-quinolinolato)zinc (II)(abbreviation: Znq), etc., metal complexes having a quinoline skeleton or a benzoquinoline skeleton and the like. In addition, bis[2-(2-benzoxazolyl)phenolato]zinc(I I) (Abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phenolato]zinc(I) I) Metal complexes having oxazole-based and thiazole-based ligands such as (abbreviation: ZnBTZ), etc. can also be used. Furthermore, in addition to metal complexes, 2-(4-biphenylyl)-5 -(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD) and 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiaz -ol-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), 2,2’,2’’-(1,3,5-benzen triyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benz imidazole (abbreviation: mDBTBIm-II), bathophenanthroline (abbreviation: BPhe n), bathocuproin (abbreviation: BCP), 2,9-bis(naphthalen-2-yl)-4 ,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen), etc. of heterocyclic compounds, and 2-[3-(dibenzothiophen-4-yl)phenyl]dibenz[f,h]qui noxaline (abbreviation: 2mDBTPDBq-II), 2-[3’-(dibenzothiophen- 4-yl)biphenyl-3-yl]dibenz[f,h]quinoxaline (abbreviation: 2mDBT BPDBq-II), 2-[3’-(9H-carbazol-9-yl)biphenyl-3- yl]dibenz[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3 ,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzof,h]quin inoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl phenyl]dibenzof,h]quinoxaline (abbreviation: 7mDBTPDBq-II), 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzof,h]quinoxali ne (abbreviation: 6mDBTPDBq-II), 4,6-bis[3-(phenanthren-9-yl phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4- dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4 ,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4, 6mCzP2Pm), etc. heterocyclic compounds having a diazine skeleton, 2-{4-[3-(N -phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl }-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), etc. heterocyclic compounds having a triazine skeleton, 3,5-bis[3-(9H-carbazol-9 -yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3 -pyridyl)phenyl]benzene (abbreviation: TmPyPB), etc. heterocyclic compounds having a pyridine skeleton, 4,4’-bis(5-methylbenzoxazol-2-yl)stilbene ( abbreviation: BzOs), etc. heteroaromatic compounds can also be used. 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) can also be used. The substances described here mainly have an electron mobility of 1×10 -6 cm 2 / Vs or higher. As long as the substance has higher electron transportability than holes, substances other than the above can also be used. In addition, an organic compound having a benzofuropyrimidine skeleton or a benzothienopyrimidine skeleton can be preferably used.

[0186] Also, 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 with high electron trapping property is added to a material with high electron transportability as described above, and by suppressing the movement of electron carriers, it becomes possible to adjust the carrier balance. Such a configuration has a great effect on suppressing problems (for example, a decrease in device lifetime) caused by electrons passing through the light-emitting layer.

[0187] <<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. For example, Group 1 metals, Group 2 metals, or their oxides, halides, carbonates, etc. can be used. In addition, a composite material of the electron transport material shown above and a material showing electron-donating properties can also be used. Examples of materials showing electron-donating properties include Group 1 metals, Group 2 metals, or their oxides. Specifically, lithium fluoride (LiF), sodium fluoride (NaF), cesium fluoride (CsF can be mentioned. ), calcium fluoride (CaF2), lithium oxide (LiO x ) and other alkaline gold Metals, alkaline earth metals, or compounds thereof can be used. A rare earth metal compound such as fluorine (ErF3) can be used. An electride may be used for 119. The electride may be, for example, calcium. Examples include a material in which electrons are highly concentrated in a mixed oxide of aluminum and ruthenium. The injection layer 119 may be made of a material that can be used in the electron transport layer 118 .

[0188] In addition, the electron injection layer 119 is made of a composite material obtained by mixing an organic compound and an electron donor. Such composite materials may be made by adding electrons to an organic compound via an electron donor. In this case, the organic compound is It is preferable that the material has excellent transport properties for the generated electrons. Specifically, for example, the above-mentioned The material constituting the electron transport layer 118 (metal complex, heteroaromatic compound, etc.) can be used. The electron donor may be any substance that exhibits electron donating properties to organic compounds. For the metal, alkali metals, alkaline earth metals and rare earth metals are preferred, and lithium, cesium, Magnesium, calcium, erbium, ytterbium, etc. Preferred are lithium metal oxides and alkaline earth metal oxides, and lithium oxide and calcium oxide are preferred. , barium oxide, etc. Also, Lewis bases such as magnesium oxide are used. It is also possible to use organic compounds such as tetrathiafulvalene (TTF). It is also possible.

[0189] Incidentally, the above-described light-emitting layer, hole injection layer, hole transport layer, electron transport layer, and electron injection layer can each be formed by a method such as vapor deposition (including vacuum vapor deposition), inkjet method, coating method, nozzle printing method , gravure printing, etc. Further, in addition to the above-described materials, inorganic compounds such as quantum dots or polymeric compounds (oligomers, dendrimers, polymers, etc.) may be used for the above-described light-emitting layer, hole injection layer , hole transport layer, electron transport layer, and electron injection layer.

[0190] Incidentally, as the quantum dots, colloidal quantum dots, alloy-type quantum dots, core-shell type quantum dots, core-type quantum dots, etc. may be used. Further, 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 may be used. Alternatively, quantum dots having 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. may be used.

[0191] As the liquid medium used in the wet process, for example, ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, halogenated hydrocarbons such as dichlorobenzene, aromatic hydrocarbons such as toluene, xylene, mesitylene, cyclohexylbenzene, aliphatic hydrocarbons such as cyclohexane, decalin, dodecane, organic solvents such as dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) can be used.

[0192] In addition, examples of the polymer compound that can be used in the light-emitting layer include, for example, poly[2-methoxy -5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (abbreviation: MEH -PPV), polyphenylene vinylene (PPV) derivatives such as poly(2,5-dioctyl-1,4-phenylenevinylene), poly(9,9-di-n-octylfluorenyl-2,7 -diyl) (abbreviation: PF8), poly[(9,9-di-n-octylfluorenyl-2,7 -diyl)-alt-(benzo[2,1,3]thiadiazole-4,8-diyl)] (abbreviation : F8BT), poly[(9,9-di-n-octylfluorenyl-2,7-diyl)- alt-(2,2'-bithiophene-5,5'-diyl)] (abbreviation: F8T2), poly[( 9,9-dioctyl-2,7-divinylenefluorenylene)-alt-(9,10-anthra cene)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-( 2,5-dimethyl-1,4-phenylene)] and other polyfluorene derivatives, poly(3-hexyl thiophene-2,5-diyl) (abbreviation: P3HT) and other polyalkylthiophene (P AT) derivatives, polyphenylene derivatives, and the like. Further, these polymer compounds and PVK, poly(2-vinylnaphthalene), poly[bis(4-phenyl)(2,4,6-tri methylphenyl)amine] (abbreviation: PTAA) and other polymer compounds may be doped with a light-emitting compound and used in the light-emitting layer. As the light-emitting compound, the light-emitting compounds listed above can be used.

[0193] As one aspect of the present invention, an organic compound having a benzofuropyrimidine skeleton or a benzothienopyrimidine skeleton and an organic compound capable of converting triplet excitation energy into light emission, and fluorescence emission Three kinds of organic compounds exhibiting light are mixed and used in the light-emitting layer 130, but a polymer compound having the above-described skeleton or function can also be used. For example, a polymer compound having a benzofuropyrimidine skeleton or a benzothienopyrimidine skeleton, a substituent capable of converting triplet excitation energy into light emission, and a substituent exhibiting fluorescence emission may be used as the light-emitting layer 130. Further, a polymer compound having a benzofuropyrimidine skeleton or a benzothienopyrimidine skeleton and a substituent capable of converting triplet excitation energy into light emission, and a low-molecular compound exhibiting fluorescence emission may be mixed to produce the light-emitting layer 130. By using the polymer compound, the utilization efficiency of the material can be improved and the production cost can be reduced. Also, a polymer compound having a benzofuropyrimidine skeleton or a benzothienopyrimidine skeleton, a substituent capable of converting triplet excitation energy into light emission, and a substituent exhibiting fluorescence emission may be used as the light-emitting layer 130. Further, a polymer compound having a benzofuropyrimidine skeleton or a benzothienopyrimidine skeleton and a substituent capable of converting triplet excitation energy into light emission, and a low-molecular compound exhibiting fluorescence emission may be mixed to produce the light-emitting layer 130. By using the polymer compound, the utilization efficiency of the material can be improved and the production cost can be reduced. ≪Substrate≫ Also, the light-emitting element according to one aspect of the present invention may be manufactured on a substrate made of glass, plastic, or the like. As the order of manufacturing on the substrate, they may be laminated in order from the electrode 101 side, or may be laminated in order from the electrode 102 side. In addition, as the substrate on which the light-emitting element according to one aspect of the present invention can be formed, for example, glass, quartz, or plastic can be used. A flexible substrate may also be used. The flexible substrate is a substrate that can be bent (flexible), and examples thereof include plastic substrates made of polycarbonate and polyarylate. Further, a film, an inorganic vapor deposition film, or the like can also be used. As long as it functions as a support in the manufacturing process of the light-emitting element, other materials may be used. Alternatively, as long as it has a function of protecting the light-emitting element, it may be used. ≪Substrate≫ Also, the light-emitting element according to one aspect of the present invention may be manufactured on a substrate made of glass, plastic, or the like. As the order of manufacturing on the substrate, they may be laminated in order from the electrode 101 side, or may be laminated in order from the electrode 102 side.

[0194] ≪Substrate≫ Also, the light-emitting element according to one aspect of the present invention may be manufactured on a substrate made of glass, plastic, or the like. As the order of manufacturing on the substrate, they may be laminated in order from the electrode 101 side, or may be laminated in order from the electrode 102 side. In addition, as the substrate on which the light-emitting element according to one aspect of the present invention can be formed, for example, glass, quartz, or plastic can be used. A flexible substrate may also be used. The flexible substrate is a substrate that can be bent (flexible), and examples thereof include plastic substrates made of polycarbonate and polyarylate. Further, a film, an inorganic vapor deposition film, or the like can also be used. As long as it functions as a support in the manufacturing process of the light-emitting element, other materials may be used. Alternatively, as long as it has a function of protecting the light-emitting element, it may be used. ≪Substrate≫

[0195] In addition, as the substrate on which the light-emitting element according to one aspect of the present invention can be formed, for example, glass, quartz, or plastic can be used. A flexible substrate may also be used. The flexible substrate is a substrate that can be bent (flexible), and examples thereof include plastic substrates made of polycarbonate and polyarylate. Further, a film, an inorganic vapor deposition film, or the like can also be used. As long as it functions as a support in the manufacturing process of the light-emitting element, other materials may be used. Alternatively, as long as it has a function of protecting the light-emitting element, it may be used. ≪Substrate≫ Also, the light-emitting element according to one aspect of the present invention may be manufactured on a substrate made of glass, plastic, or the like. As the order of manufacturing on the substrate, they may be laminated in order from the electrode 101 side, or may be laminated in order from the electrode 102 side. In addition, as the substrate on which the light-emitting element according to one aspect of the present invention can be formed, for example, glass, quartz, or plastic can be used. A flexible substrate may also be used. The flexible substrate is a substrate that can be bent (flexible), and examples thereof include plastic substrates made of polycarbonate and polyarylate. Further, a film, an inorganic vapor deposition film, or the like can also be used. As long as it functions as a support in the manufacturing process of the light-emitting element, other materials may be used. Alternatively, as long as it has a function of protecting the light-emitting element, it may be used. ≪Substrate≫ Also, the light-emitting element according to one aspect of the present invention may be manufactured on a substrate made of glass, plastic, or the like. As the order of manufacturing on the substrate, they may be laminated in order from the electrode 101 side, or may be laminated in order from the electrode 102 side. In addition, as the substrate on which the light-emitting element according to one aspect of the present invention can be formed, for example, glass, quartz, or plastic can be used. A flexible substrate may also be used. The flexible substrate is a substrate that can be bent (flexible), and examples thereof include plastic substrates made of polycarbonate and polyarylate. Further, a film, an inorganic vapor deposition film, or the like can also be used. As long as it functions as a support in the manufacturing process of the light-emitting element, other materials may be used. Alternatively, as long as it has a function of protecting the light-emitting element, it may be used.

[0196] For example, in the present invention and the like, light-emitting elements can be formed using various substrates. The type of the substrate is not particularly limited. As an example of the substrate, a semiconductor substrate (e.g., a single crystal substrate or a silicon substrate), an SOI substrate, a glass substrate, a quartz substrate, a plastic 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 bonded film, a fibrous material-containing cellulose nanofiber (CNF) or paper, or a base film and the like. As an example of the glass substrate, there are barium borosilicate glass, aluminoborosilicate glass, or soda lime glass and the like. Examples of the flexible substrate, the bonded film, the base film and the like include the following. For example, polyethylene terephthalate (PET), poly ethylene naphthalate (PEN), polyethersulfone (PES), polytetrafluoro ethylene (PTFE)-represented plastics. Or, as an example, there are resins such as acrylic and the like. Or, as an example, there are polypropylene, polyester, poly vinyl fluoride, or polyvinyl chloride and the like. Or, as an example, there are polyamide, polyimide, aramid, epoxy, an inorganic vapor deposition film, or papers and the like.

[0197] Also, as the substrate, a flexible substrate can be used, and a light-emitting element can be directly formed 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 this time, the light-emitting element can be transferred to a substrate with poor heat resistance or a flexible substrate. Oh, for the above-described release layer, for example, a laminated structure of inorganic films such as a tungsten film and a silicon oxide film or a structure in which a resin film such as polyimide is formed on a substrate can be used.

[0198] 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 the light-emitting element may be disposed on another substrate. As an example of the substrate to which the light-emitting element is transferred, in addition to the above-described substrate, a cellophane substrate, a stone substrate, a wood substrate, a cloth substrate (including natural fibers (silk, cotton, hemp), synthetic fibers (nylon, polyurethane, polyester) or regenerated fibers (acetate tow, cupra, rayon, recycled polyester), etc.), a leather substrate, or a rubber substrate is available. 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.

[0199] Also, for example, a field effect transistor (FET) may be formed on the above-described substrate, and the 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 by the FET can be fabricated.

[0200] As described above, the configuration shown in the present embodiment can be used in appropriate combination with other embodiments.

[0201] (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 FIG. 5. In FIG. 5, portions having the same functions as the reference numerals shown in FIG. 1(A) are given the same hatch pattern, and the reference numerals may be omitted. Also, for parts having the same function, the same reference numerals are given, and detailed descriptions thereof are omitted where appropriate. There are cases.

[0202] <Configuration Example 2 of Light-Emitting Element> FIG. 5 is a schematic cross-sectional view of a light-emitting element 250.

[0203] The light-emitting element 250 shown in FIG. 5 has a plurality of light-emitting units (light-emitting unit 106 and light-emitting unit 108) between a pair of electrodes (electrode 101 and electrode 102). Among the plurality of light-emitting units, any one of the light-emitting units preferably has the same configuration as the EL layer 100 shown in FIG. 1(A). That is, the light-emitting element 150 shown in FIG. 1(A) has one light-emitting unit, and the light-emitting element 250 preferably has a plurality of light-emitting units. In the light-emitting element 250, although electrode 101 functions as an anode and electrode 102 functions as a cathode, the configuration of the light-emitting element 250 may be reversed in the following description. In the light-emitting element 250 shown in FIG. 5, 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 same configuration as the EL layer 100 for the light-emitting unit 108. In FIG. 1(A), the light-emitting element 150 has one light-emitting unit, and the light-emitting element 250 preferably has a plurality of light-emitting units. In the light-emitting element 250, electrode 101 functions as an anode and electrode 102 functions as a cathode. However, the configuration of the light-emitting element 250 may be reversed. In the light-emitting element 250, electrode 101 functions as an anode and electrode 102 functions as a cathode. However, the configuration of the light-emitting element 250 may be reversed. The following description will be made on the assumption that electrode 101 functions as an anode and electrode 102 functions as a cathode in the light-emitting element 250. However, the configuration of the light-emitting element 250 may be reversed.

[0204] In the light-emitting element 250 shown in FIG. 5, 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 same configuration as the EL layer 100 for the light-emitting unit 108. In the light-emitting element 250 shown in FIG. 5, 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 same configuration as the EL layer 100 for the light-emitting unit 108.

[0205] The light-emitting element 250 also has a light-emitting layer 120 and a light-emitting layer 170. The light-emitting unit 106 further has a hole injection layer 111, a hole transport layer 112, an electron transport layer 113, and an electron injection layer 114 in addition to the light-emitting layer 120. The light-emitting unit 108 has a light-emitting layer 170. The light-emitting unit 106 further has a hole injection layer 111, a hole transport layer 112, an electron transport layer 113, and an electron injection layer 114 in addition to the light-emitting layer 120. The light-emitting unit 108 has a light-emitting layer 170. In addition to this, it has a hole injection layer 116, a hole transport layer 117, an electron transport layer 118, and an electron injection layer 11 9.

[0206] The light-emitting element 250 may contain an organic compound according to one aspect of the present invention in any layer included in the light-emitting unit 106 and the light-emitting unit 108. Note that the layer containing the organic compound is preferably the electron transport layer 113 or the electron transport layer 118, and more preferably the light-emitting layer 120 or the light-emitting layer 170. It suffices that the organic compound according to one aspect of the present invention is included. Preferably, it is the electron transport layer 113 or the electron transport layer 118, and more preferably the light-emitting layer 120 or the light-emitting layer 170.

[0207] The charge generation layer 115 may have 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. Further, both of these configurations may be laminated.

[0208] When the charge generation layer 115 contains a composite material of an organic compound and an acceptor substance, the composite material may be the same as the composite material 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, and polymer compounds (oligomers, dendrimers, polymers, etc.) can be used. Note that as the organic compound, those having a hole mobility of 1×10 cm / Vs or more are preferably applied. However, other substances may be used as long as they have higher hole transportability than electrons. Since the composite material of the organic compound and the acceptor substance is excellent in carrier injection property and carrier transport property, low voltage driving and low current driving can be realized. Note that the surface on the anode side of the light-emitting unit is in contact with the charge generation layer 115. -6 cm 2 / Vs or more are preferably applied. However, other substances may be used as long as they have higher hole transportability than electrons. Since the composite material of the organic compound and the acceptor substance is excellent in carrier injection property and carrier transport property, low voltage driving and low current driving can be realized. Note that the surface on the anode side of the light-emitting unit is in contact with the charge generation layer 115. In this case, since the charge generation layer 115 also serves as the hole injection layer or the hole transport layer of the light emitting unit, it is possible not to provide a hole injection layer or a hole transport layer in the light emitting unit. Alternatively, when the surface on the cathode side of the light emitting unit is in contact with the charge generation layer 115, since the charge generation layer 115 can also serve as the electron injection layer or the electron transport layer of the light emitting unit, it is possible not to provide an electron injection layer or an electron transport layer in the light emitting unit. That is also acceptable.

[0209] 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 other layers formed of 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 compound selected from electron donating substances and a compound with high electron transportability. Further, 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 film. That is also acceptable.

[0210] Note that the charge generation layer 115 sandwiched between the light emitting unit 106 and the light emitting unit 108 only needs to inject electrons into one light emitting unit and holes into the other light emitting unit when a voltage is applied between the electrode 101 and the electrode 102. For example, in FIG. 5, when a voltage is applied such that the potential of the electrode 1 01 is higher than the potential of the electrode 102, the charge generation layer 115 injects electrons into the light emitting unit 106 and holes into the light emitting unit 108.

[0211] Note that from the viewpoint of light extraction efficiency, the charge generation layer 115 has translucency with respect to visible light (specifically Preferably, it has a visible light transmittance of 40% or more with respect to the charge generation layer 115. Further, the charge generation layer 115 functions even if it has a lower conductivity than the pair of electrodes (electrode 101 and electrode 102). than the pair of electrodes (electrode 101 and electrode 102).

[0212] 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 layer is laminated can be suppressed. In the case where the light emitting layer is laminated, an increase in the driving voltage can be suppressed.

[0213] In FIG. 5, a light emitting device having two light emitting units has been described, but the present invention can be similarly applied to a light emitting device in which three or more light emitting units are laminated. 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 a light emitting device with a longer lifespan can be realized. Further, a light emitting device with low power consumption can be realized. 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 a light emitting device with a longer lifespan can be realized. Further, a light emitting device with low power consumption can be realized. 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 a light emitting device with a longer lifespan can be realized. Further, a light emitting device with low power consumption can be realized. 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 a light emitting device with a longer lifespan can be realized. Further, a light emitting device with low power consumption can be realized.

[0214] In each of the above configurations, the light emitting colors exhibited by the guest materials used in the light emitting unit 106 and the light emitting unit 108 may be the same as or different from each other. When the guest material has a function of emitting light of the same color in the light emitting unit 106 and the light emitting unit 108, the light emitting device 250 is preferably a light emitting device that exhibits high light emission brightness with a small current value. Further, when the guest material has a function of emitting light of different colors in the light emitting unit 106 and the light emitting unit 108, the light emitting device 250 is preferably a light emitting device that exhibits multi-color light 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 light emitting device 250 exhibits In each of the above configurations, the light emitting colors exhibited by the guest materials used in the light emitting unit 106 and the light emitting unit 108 may be the same as or different from each other. When the guest material has a function of emitting light of the same color in the light emitting unit 106 and the light emitting unit 108, the light emitting device 250 is preferably a light emitting device that exhibits high light emission brightness with a small current value. Further, when the guest material has a function of emitting light of different colors in the light emitting unit 106 and the light emitting unit 108, the light emitting device 250 is preferably a light emitting device that exhibits multi-color light 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 light emitting device 250 exhibits In each of the above configurations, the light emitting colors exhibited by the guest materials used in the light emitting unit 106 and the light emitting unit 108 may be the same as or different from each other. When the guest material has a function of emitting light of the same color in the light emitting unit 106 and the light emitting unit 108, the light emitting device 250 is preferably a light emitting device that exhibits high light emission brightness with a small current value. Further, when the guest material has a function of emitting light of different colors in the light emitting unit 106 and the light emitting unit 108, the light emitting device 250 is preferably a light emitting device that exhibits multi-color light 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 light emitting device 250 exhibits In each of the above configurations, the light emitting colors exhibited by the guest materials used in the light emitting unit 106 and the light emitting unit 108 may be the same as or different from each other. When the guest material has a function of emitting light of the same color in the light emitting unit 106 and the light emitting unit 108, the light emitting device 250 is preferably a light emitting device that exhibits high light emission brightness with a small current value. Further, when the guest material has a function of emitting light of different colors in the light emitting unit 106 and the light emitting unit 108, the light emitting device 250 is preferably a light emitting device that exhibits multi-color light 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 light emitting device 250 exhibits In each of the above configurations, the light emitting colors exhibited by the guest materials used in the light emitting unit 106 and the light emitting unit 108 may be the same as or different from each other. When the guest material has a function of emitting light of the same color in the light emitting unit 106 and the light emitting unit 108, the light emitting device 250 is preferably a light emitting device that exhibits high light emission brightness with a small current value. Further, when the guest material has a function of emitting light of different colors in the light emitting unit 106 and the light emitting unit 108, the light emitting device 250 is preferably a light emitting device that exhibits multi-color light 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 light emitting device 250 exhibits In each of the above configurations, the light emitting colors exhibited by the guest materials used in the light emitting unit 106 and the light emitting unit 108 may be the same as or different from each other. When the guest material has a function of emitting light of the same color in the light emitting unit 106 and the light emitting unit 108, the light emitting device 250 is preferably a light emitting device that exhibits high light emission brightness with a small current value. Further, when the guest material has a function of emitting light of different colors in the light emitting unit 106 and the light emitting unit 108, the light emitting device 250 is preferably a light emitting device that exhibits multi-color light 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 light emitting device 250 exhibits In each of the above configurations, the light emitting colors exhibited by the guest materials used in the light emitting unit 106 and the light emitting unit 108 may be the same as or different from each other. When the guest material has a function of emitting light of the same color in the light emitting unit 106 and the light emitting unit 108, the light emitting device 250 is preferably a light emitting device that exhibits high light emission brightness with a small current value. Further, when the guest material has a function of emitting light of different colors in the light emitting unit 106 and the light emitting unit 108, the light emitting device 250 is preferably a light emitting device that exhibits multi-color light 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 light emitting device 250 exhibits In each of the above configurations, the light emitting colors exhibited by the guest materials used in the light emitting unit 106 and the light emitting unit 108 may be the same as or different from each other. When the guest material has a function of emitting light of the same color in the light emitting unit 106 and the light emitting unit 108, the light emitting device 250 is preferably a light emitting device that exhibits high light emission brightness with a small current value. Further, when the guest material has a function of emitting light of different colors in the light emitting unit 106 and the light emitting unit 108, the light emitting device 250 is preferably a light emitting device that exhibits multi-color light 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 light emitting device 250 exhibits The resulting emission spectrum is light synthesized from emissions having different emission peaks, so at least it has an emission spectrum with at least two maxima.

[0215] 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. 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. 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. 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. 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. 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. 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. 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.

[0216] It is preferable to use the configuration of the light emitting layer 130 shown in Embodiment 1 for one or both of the light emitting layer 120 and the light emitting layer 170. By adopting this configuration, a light emitting element with good luminous efficiency and reliability can be obtained. The guest material contained in the light emitting layer 130 is a fluorescent material. Therefore, by using the configuration of the light emitting layer 130 shown in Embodiment 1 for one or both of the light emitting layer 120 and the light emitting layer 170, a light emitting element with a sharp emission spectrum and high color purity can be obtained. It is preferable to use the configuration of the light emitting layer 130 shown in Embodiment 1 for one or both of the light emitting layer 120 and the light emitting layer 170. By adopting this configuration, a light emitting element with good luminous efficiency and reliability can be obtained. The guest material contained in the light emitting layer 130 is a fluorescent material. Therefore, by using the configuration of the light emitting layer 130 shown in Embodiment 1 for one or both of the light emitting layer 120 and the light emitting layer 170, a light emitting element with a sharp emission spectrum and high color purity can be obtained. It is preferable to use the configuration of the light emitting layer 130 shown in Embodiment 1 for one or both of the light emitting layer 120 and the light emitting layer 170. By adopting this configuration, a light emitting element with good luminous efficiency and reliability can be obtained. The guest material contained in the light emitting layer 130 is a fluorescent material. Therefore, by using the configuration of the light emitting layer 130 shown in Embodiment 1 for one or both of the light emitting layer 120 and the light emitting layer 170, a light emitting element with a sharp emission spectrum and high color purity can be obtained. It is preferable to use the configuration of the light emitting layer 130 shown in Embodiment 1 for one or both of the light emitting layer 120 and the light emitting layer 170. By adopting this configuration, a light emitting element with good luminous efficiency and reliability can be obtained. The guest material contained in the light emitting layer 130 is a fluorescent material. Therefore, by using the configuration of the light emitting layer 130 shown in Embodiment 1 for one or both of the light emitting layer 120 and the light emitting layer 170, a light emitting element with a sharp emission spectrum and high color purity can be obtained. It is preferable to use the configuration of the light emitting layer 130 shown in Embodiment 1 for one or both of the light emitting layer 120 and the light emitting layer 170. By adopting this configuration, a light emitting element with good luminous efficiency and reliability can be obtained. The guest material contained in the light emitting layer 130 is a fluorescent material. Therefore, by using the configuration of the light emitting layer 130 shown in Embodiment 1 for one or both of the light emitting layer 120 and the light emitting layer 170, a light emitting element with a sharp emission spectrum and high color purity can be obtained. It is preferable to use the configuration of the light emitting layer 130 shown in Embodiment 1 for one or both of the light emitting layer 120 and the light emitting layer 170. By adopting this configuration, a light emitting element with good luminous efficiency and reliability can be obtained. The guest material contained in the light emitting layer 130 is a fluorescent material. Therefore, by using the configuration of the light emitting layer 130 shown in Embodiment 1 for one or both of the light emitting layer 120 and the light emitting layer 170, a light emitting element with a sharp emission spectrum and high color purity can be obtained.

[0217] Also, in the case of a light emitting element in which three or more light emitting units are stacked, the emission colors exhibited by the guest materials used in each light emitting unit may be the same or different from each other. When there are a plurality of light emitting units exhibiting the same color emission, the emission colors exhibited by these plurality of light emitting units can obtain a high emission luminance at a lower current value compared to other colors. Such a configuration can be suitably used for adjusting the emission color. In particular, it is suitable when using guest materials having different luminous efficiencies and exhibiting different emission colors. For example, in the case of having three layers of light emitting units, two layers have light emitting units having the same color fluorescent material, and the emission color is different from that of the fluorescent material. Also, in the case of a light emitting element in which three or more light emitting units are stacked, the emission colors exhibited by the guest materials used in each light emitting unit may be the same or different from each other. When there are a plurality of light emitting units exhibiting the same color emission, the emission colors exhibited by these plurality of light emitting units can obtain a high emission luminance at a lower current value compared to other colors. Such a configuration can be suitably used for adjusting the emission color. In particular, it is suitable when using guest materials having different luminous efficiencies and exhibiting different emission colors. For example, in the case of having three layers of light emitting units, two layers have light emitting units having the same color fluorescent material, and the emission color is different from that of the fluorescent material. Also, in the case of a light emitting element in which three or more light emitting units are stacked, the emission colors exhibited by the guest materials used in each light emitting unit may be the same or different from each other. When there are a plurality of light emitting units exhibiting the same color emission, the emission colors exhibited by these plurality of light emitting units can obtain a high emission luminance at a lower current value compared to other colors. Such a configuration can be suitably used for adjusting the emission color. In particular, it is suitable when using guest materials having different luminous efficiencies and exhibiting different emission colors. For example, in the case of having three layers of light emitting units, two layers have light emitting units having the same color fluorescent material, and the emission color is different from that of the fluorescent material. Also, in the case of a light emitting element in which three or more light emitting units are stacked, the emission colors exhibited by the guest materials used in each light emitting unit may be the same or different from each other. When there are a plurality of light emitting units exhibiting the same color emission, the emission colors exhibited by these plurality of light emitting units can obtain a high emission luminance at a lower current value compared to other colors. Such a configuration can be suitably used for adjusting the emission color. In particular, it is suitable when using guest materials having different luminous efficiencies and exhibiting different emission colors. For example, in the case of having three layers of light emitting units, two layers have light emitting units having the same color fluorescent material, and the emission color is different from that of the fluorescent material. Also, in the case of a light emitting element in which three or more light emitting units are stacked, the emission colors exhibited by the guest materials used in each light emitting unit may be the same or different from each other. When there are a plurality of light emitting units exhibiting the same color emission, the emission colors exhibited by these plurality of light emitting units can obtain a high emission luminance at a lower current value compared to other colors. Such a configuration can be suitably used for adjusting the emission color. In particular, it is suitable when using guest materials having different luminous efficiencies and exhibiting different emission colors. For example, in the case of having three layers of light emitting units, two layers have light emitting units having the same color fluorescent material, and the emission color is different from that of the fluorescent material. Also, in the case of a light emitting element in which three or more light emitting units are stacked, the emission colors exhibited by the guest materials used in each light emitting unit may be the same or different from each other. When there are a plurality of light emitting units exhibiting the same color emission, the emission colors exhibited by these plurality of light emitting units can obtain a high emission luminance at a lower current value compared to other colors. Such a configuration can be suitably used for adjusting the emission color. In particular, it is suitable when using guest materials having different luminous efficiencies and exhibiting different emission colors. For example, in the case of having three layers of light emitting units, two layers have light emitting units having the same color fluorescent material, and the emission color is different from that of the fluorescent material. Also, in the case of a light emitting element in which three or more light emitting units are stacked, the emission colors exhibited by the guest materials used in each light emitting unit may be the same or different from each other. When there are a plurality of light emitting units exhibiting the same color emission, the emission colors exhibited by these plurality of light emitting units can obtain a high emission luminance at a lower current value compared to other colors. Such a configuration can be suitably used for adjusting the emission color. In particular, it is suitable when using guest materials having different luminous efficiencies and exhibiting different emission colors. For example, in the case of having three layers of light emitting units, two layers have light emitting units having the same color fluorescent material, and the emission color is different from that of the fluorescent material. By using a single layer of a light-emitting unit having a phosphorescent material, the emission intensities of fluorescence and phosphorescence can be adjusted. That is, the emission intensity of each color can be adjusted according to the number of light-emitting units.

[0218] In the case of a light-emitting device having two layers of such fluorescence light-emitting units and one layer of phosphorescence light-emitting units, a light-emitting device containing two layers of a light-emitting unit containing a blue fluorescent material and one layer of a light-emitting unit containing a yellow phosphorescent material, a light-emitting device having two layers of a light-emitting unit containing a blue fluorescent material and one layer of a light-emitting unit containing a red phosphorescent material and a green phosphorescent material, or a light-emitting device having two layers of a light-emitting unit containing a blue fluorescent material and one layer of a light-emitting unit containing a red phosphorescent material, a yellow phosphorescent material, and a green phosphorescent material is preferable because white light emission can be obtained efficiently.

[0219] Further, at least one of the light-emitting layer 120 or 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, at least one of the light-emitting layer 120 or the light-emitting layer 170 may 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 a light-emitting layer, a material having hole transport properties is used as the host material of the first light-emitting layer, and a material having electron transport properties is used as the host material of the second light-emitting layer. 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 the same color light or materials having a function of emitting different color light. A plurality of light-emitting materials having functions of emitting light of different colors from each other ​​​​​​​​​​​​​​A configuration with materials can obtain high-color-rendering white light emission composed of three primary colors or four or more emission colors. This is also possible.

[0220] Note that this embodiment can be appropriately combined with other embodiments.

[0221] (Embodiment 3) In this embodiment, a light-emitting device using the light-emitting element described in Embodiment 1 and Embodiment 2 will be described with reference to FIGS. 6(A) and 6(B). FIG. 6(A) is a top view showing the light-emitting device, and FIG. 6(B) is a cross-sectional view taken along A-B and C-D of FIG. 6(A). This light-emitting device includes a drive circuit portion (source-side drive circuit) 601, a pixel portion 602, and a drive circuit portion (gate-side drive circuit) 603, which are indicated by dotted lines and control the light emission of the light-emitting element. Further, 604 is a sealing substrate, 625 is a drying material, and 605 is a sealing material. The inside surrounded by the sealing material 605 is a space 607.

[0222] FIG. 6(A) is a top view showing the light-emitting device, and FIG. 6(B) is a cross-sectional view taken along A-B and C-D of FIG. 6(A). This light-emitting device includes a drive circuit portion (source-side drive circuit) 601, a pixel portion 602, and a drive circuit portion (gate-side drive circuit) 603, which are indicated by dotted lines and control the light emission of the light-emitting element. In addition, 604 is a sealing substrate, 625 is a drying material, and 605 is a sealing material. The inside surrounded by the sealing material 605 is a space 607. Further, 604 is a sealing substrate, 625 is a drying material, and 605 is a sealing material. The inside surrounded by the sealing material 605 is a space 607. The inside surrounded by the sealing material 605 is a space 607.

[0223] Note that the routing wiring 608 is a wiring for transmitting signals input to the source-side drive circuit 601 and the gate-side drive circuit 603, and receives a video signal, a clock signal, a start signal, a reset signal, etc. from an FPC (Flexible Printed Circuit) 609 serving as an external input terminal. Although only the FPC is shown here, a printed wiring board (PWB) may be attached to this FPC. The light-emitting device in this specification includes not only the light-emitting device main body but also a state in which an FPC or a PWB is attached thereto. Note that the routing wiring 608 is a wiring for transmitting signals input to the source-side drive circuit 601 and the gate-side drive circuit 603, and receives a video signal, a clock signal, a start signal, a reset signal, etc. from an FPC (Flexible Printed Circuit) 609 serving as an external input terminal. Although only the FPC is shown here, a printed wiring board (PWB) may be attached to this FPC. The light-emitting device in this specification includes not only the light-emitting device main body but also a state in which an FPC or a PWB is attached thereto. Note that the routing wiring 608 is a wiring for transmitting signals input to the source-side drive circuit 601 and the gate-side drive circuit 603, and receives a video signal, a clock signal, a start signal, a reset signal, etc. from an FPC (Flexible Printed Circuit) 609 serving as an external input terminal. Although only the FPC is shown here, a printed wiring board (PWB) may be attached to this FPC. The light-emitting device in this specification includes not only the light-emitting device main body but also a state in which an FPC or a PWB is attached thereto. Although only the FPC is shown here, a printed wiring board (PWB) may be attached to this FPC. The light-emitting device in this specification includes not only the light-emitting device main body but also a state in which an FPC or a PWB is attached thereto.

[0224] Next, the cross-sectional structure of the above light-emitting device will be described with reference to FIG. 6(B). On the element substrate 610 a driving circuit section and a pixel section are formed. Here, one pixel in the source-side driving circuit 601 which is a driving circuit section and the pixel section 602 is shown.

[0225] Note that the source-side driving circuit 601 is formed of a CMOS circuit combining an n-channel type TFT 623 and a p-channel type TFT 624 and. Also, the driving circuit may be formed of various CMOS circuits, P MOS circuits, and NMOS circuits. In this embodiment, a driver integrated type in which a driving circuit is formed on the substrate is shown, but this is not necessarily required, and the driving circuit can be formed outside the substrate without.

[0226] Also, the pixel section 602 is formed of pixels including a switching TFT 611, a current control TFT 612, and a first electrode 613 electrically connected to the drain thereof. Note that an insulator 614 is formed so as to cover the end portion of the first electrode 613. The insulator 614 can be formed by using a positive type photosensitive resin film.

[0227] Also, in order to make the covering property of the film formed on the insulator 614 good, a surface having a curvature is formed at the upper end portion or the lower end portion of the insulator 614 so as to. For example, when photosensitive acrylic is used as the material of the insulator 614, it is preferable to provide a curved surface only at the upper end portion of the insulator 614 so. The radius of curvature of the curved surface is preferably 0.2 μm or more and 0.3 μm or less. Also, as the insulator 614, either a negative type or a positive type photosensitive material can be used.

[0228] An EL layer 616 and a second electrode 617 are respectively formed on the first electrode 613​​ Here, the material used for the first electrode 613 functioning as an anode is a material having a work function of It is desirable to use a material with a large capacitance. For example, an ITO film or an indium tin oxide film containing silicon. Indium tin oxide film, indium oxide film containing 2wt% to 20wt% zinc oxide, nitride In addition to single-layer films such as titanium film, chromium film, tungsten film, Zn film, and Pt film, titanium nitride film and Lamination with a film mainly composed of aluminum, titanium nitride film and a film mainly composed of aluminum A three-layer structure of a titanium nitride film and a silicon nitride film can be used. The resistance of the anode is low, good ohmic contact can be achieved, and the anode can function as well. This can be done.

[0229] The EL layer 616 is formed by deposition using a deposition mask, inkjet printing, or spin coating. The EL layer 616 can be formed by various methods such as the above. The polymer may be a polymer compound (including an oligomer or a dendrimer).

[0230] Furthermore, a material for a second electrode 617 formed on the EL layer 616 and functioning as a cathode As the material, materials with a small work function (Al, Mg, Li, Ca, or alloys or compounds of these) It is preferable to use a material such as MgAg, MgIn, or AlLi. In the case where the generated light is transmitted through the second electrode 617, a thin film is used as the second electrode 617. A thin metal film and a transparent conductive film (ITO, containing 2wt% to 20wt% zinc oxide) Indium oxide, silicon-containing indium tin oxide, zinc oxide (ZnO, etc.) It is better to use layers.

[0231] Note that the first electrode 613, the EL layer 616, and the second electrode 617 form a light-emitting element 618. The light-emitting element 618 preferably has the configurations of Embodiment 1 and Embodiment 2. Note that although a plurality of light-emitting elements are formed in the pixel portion, in the light-emitting device of the present embodiment, both light-emitting elements having the configurations described in Embodiment 1 and Embodiment 2 and light-emitting elements having other configurations may be included. Furthermore, by bonding the sealing substrate 604 to the element substrate 610 with the sealing material 605, a structure is formed in which the light-emitting element 618 is provided in a space 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealing material 605. Note that the space 607 is filled with a filling material, and in addition to the case where an inert gas (such as nitrogen or argon) is filled, it may be filled with a resin or a drying material or both.

[0232] It is preferable to use an epoxy-based resin or glass frit for the sealing material 605. Also, these materials are desirably materials that hardly transmit moisture and oxygen. Further, as materials for the sealing substrate 604, in addition to a glass substrate or a quartz substrate, a plastic substrate made of FRP (Fiber Reinforced Plastics), PVF (polyvinyl fluoride), polyester, or acrylic can be used.

[0233]

[0234] As described above, a light-emitting device using the light-emitting elements described in Embodiment 1 and Embodiment 2 can be obtained.

[0235] <Configuration Example 1 of Light-Emitting Device> In FIG. 7, as an example of a display device, a light-emitting element that exhibits white light emission is formed, and a coloring layer (color filter) An example of a light-emitting device having a filter is shown.

[0236] In FIG. 7(A), a substrate 1001, an underlying insulating film 1002, a gate insulating film 1003, gate electrodes 1006, 1007, 1008, a first interlayer insulating film 1020, a second interlayer insulating film 1021 , a peripheral portion 1042, a pixel portion 1040, a driving circuit portion 1041, first electrodes 102 4W, 1024R, 1024G, 1024B of a light-emitting element, a partition wall 1026, an EL layer 1028, a light-emitting element second electrode 1029, a sealing substrate 1031, a sealing material 1032, a red pixel 1044R, green pixel 1044G, a blue pixel 1044B, a white pixel 1044W, etc. are shown.

[0237] Further, in FIG. 7(A), a colored layer (a red colored layer 1034R, a green colored layer 1034G, a blue colored layer 1034B) is provided on a transparent base material 1033. Further, a black layer (black matrix lix) 1035 may be further provided. The transparent base material 1 033 provided with the colored layer and the black layer is aligned and fixed to the substrate 1001. Note that the colored layer and the black layer are covered with an overcoat layer 1036. Further, in FIG. 7(A), light emitted from the EL layer 1028 includes light that exits to the outside without passing through the colored layer and light that passes through the colored layers of each color and exits to the outside. The light that does not pass through the colored layer is white, and the light that passes through the colored layer is red, blue, and green. Therefore, an image can be expressed by four-color pixels.

[0238] In FIG. 7(B), an example in which a red colored layer 1034R, a green colored layer 1034G, and a blue colored layer 103 4B are formed between the gate insulating film 1003 and the first interlayer insulating film 1020 is shown. As shown in FIG. 7(B), the colored layer may be provided between the substrate 1001 and the sealing substrate 1031. Yes.

[0239] In addition, in the light-emitting device described above, the light is extracted from the side of the substrate 1001 on which the TFT is formed (bottom emission type) light-emitting device, but it may also be a light-emitting device having a structure (top emission type) that emits light from the side of the sealing substrate 1031.

[0240] <Configuration Example 2 of Light-Emitting Device> Cross-sectional views of the top emission type light-emitting device are shown in FIGS. 8(A) and (B). In this case, the substrate 1001 can be a substrate that does not transmit light. Until a connection electrode connecting the TFT and the anode of the light-emitting element is fabricated, it is formed in the same manner as the bottom emission type light-emitting device. Thereafter, a third interlayer insulating film 1037 is formed to cover the electrode 1022. This insulating film may serve as a planarization film. The third interlayer insulating film 1037 can be formed using the same materials as the second interlayer insulating film 1021, as well as various other materials.

[0241] The lower electrodes 1025W, 1025R, 1025G, and 1025B of the light-emitting element are anodes here, but they may also be cathodes. Further, in the case of a top emission type light-emitting device as shown in FIGS. 8(A) and (B), the lower electrodes 1025W, 1025R, 1025G, and 1025B are preferably reflective electrodes. ) The second electrode 1029 preferably has a function of reflecting light and a function of transmitting light. Further, it is preferable that a microcavity structure is applied between the second electrode 1029 and the lower electrodes 1025W, 1025R, 1025G, and 1025B to have a function of amplifying light of a specific wavelength. The configuration of the EL layer 1028 is the same as that in Embodiment 1 and Embodiment 1025G, and the lower electrode 1025B to have a function of amplifying light of a specific wavelength. The configuration of the EL layer 1028 is the same as that in Embodiment 1 and Embodiment ​​ Adopt the configuration as described in state 2, and use an element structure that can obtain white light emission.

[0242] In FIGS. 7(A), 7(B), 8(A) and 8(B), E where white light emission can be obtained As the configuration of the EL layer, it may be realized by using a plurality of light emitting layers, using a plurality of light emitting units, etc. Note that the configuration for obtaining white light emission is not limited to these.

[0243] In the top emission structure as shown in FIGS. 8(A) and (B), a sealing substrate 1031 provided with a coloring layer (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B) can be used for sealing. A black layer (black matrix) 1030 may be provided on the sealing substrate 1031 so as to be located between pixels. The coloring layer (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B) and the black layer (black matrix) 1030 may be covered by an overcoat layer. Note that a light-transmissive substrate is used for the sealing substrate 1031. 4R, green coloring layer 1034G, blue coloring layer 1034B) for sealing. On the sealing substrate 1031, a black layer (black matrix) 1030 may be provided so as to be located between pixels. The coloring layer (red coloring layer 1034R , green coloring layer 1034G, blue coloring layer 1034B) and the black layer (black matrix ) 1030 may be covered by an overcoat layer. Note that the sealing substrate 1031 is made of a light-transmissive substrate.

[0244] In addition, FIG. 8(A) shows a configuration for performing full-color display in three colors of red, green, and blue. However, as shown in FIG. 8( B), full-color display may be performed in four colors of red, green, blue, and white. Also, the configuration for performing full-color display is not limited to these. For example, full-color display may be performed in four colors of red, green, blue, and yellow.

[0245] The light emitting element according to one aspect of the present invention uses a fluorescent material as a guest material. Since the spectrum of the fluorescent material is sharper than that of the phosphorescent material, high-color-purity light emission can be obtained. Therefore, by using the light emitting element in the light emitting device shown in this embodiment, color reproducibility is improved. is improved.​ Therefore, a light emitting device with high light emission efficiency can be obtained.

[0246] As described above, a light emitting device using the light emitting elements described in the first and second embodiments can be obtained.

[0247] Note that this embodiment mode can be appropriately combined with other embodiment modes.

[0248] (Embodiment 4) In this embodiment, an electronic device and a display device according to one embodiment of the present invention will be described.

[0249] According to one embodiment of the present invention, a highly reliable electronic device and display having a flat surface and high light emission efficiency can be provided. According to one embodiment of the present invention, a reliable display device having a curved surface and high luminous efficiency can be manufactured. The light-emitting element of one embodiment of the present invention has high color purity. Therefore, when the light-emitting element is used in the light-emitting device described in this embodiment, By this, it is possible to obtain electronic devices and display devices with high color reproducibility.

[0250] Examples of electronic devices include television sets, desktop or notebook PCs, etc. Computers, monitors for computers, digital cameras, digital video cameras Cameras, digital photo frames, mobile phones, portable game consoles, personal digital assistants, audio playback Examples of such devices include large gaming machines such as pachinko machines.

[0251] A portable information terminal 900 shown in FIGS. 9A and 9B includes a housing 901, a housing 902, a display unit 90 3, and a hinge portion 905.

[0252] The housing 901 and the housing 902 are connected by a hinge portion 905. The mobile information terminal 900 includes: It can be unfolded as shown in Fig. 9(B) from the folded state (Fig. 9(A)). Thereby, it has excellent portability when carried, and has excellent visibility due to a large display area when used.

[0253] The portable information terminal 900 is provided with a flexible display unit 903 across the housing 901 and the housing 902 connected by a hinge unit 905.

[0254] The light-emitting device manufactured using one aspect of the present invention can be used for the display unit 903. Thus, a portable information terminal with high reliability can be manufactured.

[0255] The display unit 903 can display at least one of document information, still images, moving images, etc. When document information is displayed on the display unit 903, the portable information terminal 900 can be used as an e-book terminal.

[0256] When the portable information terminal 900 is unfolded, the display unit 903 is held in a largely curved form. For example, the display unit 903 is held including a portion curved with a curvature radius of 1 mm or more and 50 mm or less, preferably 5 mm or more and 30 mm or less. A part of the display unit 903 has pixels continuously arranged from the housing 901 to the housing 902, and can perform a curved surface display.

[0257] The display unit 903 functions as a touch panel and can be operated by a finger, a stylus, etc.

[0258] The display unit 903 is preferably composed of a single flexible display. Thereby, continuous display without interruption between the housing 901 and the housing 902 can be performed. ​​​​​​​​​This is possible. In addition, each of the housing 901 and the housing 902 may be configured with a display .

[0259] The hinge portion 905 preferably has a locking mechanism so that when the portable information terminal 900 is unfolded, the angle between the housing 901 and the housing 902 does not become larger than a predetermined angle. For example, the angle at which the lock is engaged (it cannot be opened further) is preferably 90 degrees or more and less than 180 degrees, and typically, it can be 90 degrees, 120 degrees, 135 degrees, 150 degrees, or 17 5 degrees, etc. Thereby, the convenience, safety, and reliability of the portable information terminal 900 can be enhanced. When the hinge portion 905 has a locking mechanism, it is possible to prevent the display portion 903 from being damaged without applying excessive force to the display portion 903. Therefore, a highly reliable portable information terminal can be realized.

[0260] The housing 901 and the housing 902 may have a power button, operation buttons, an external connection port, a speaker, a microphone, etc.

[0261] One of the housing 901 or the housing 902 is provided with a wireless communication module, and it is possible to transmit and receive data via a computer network such as the Internet, a LAN (Local Area Network), or Wi-Fi (registered trademark ).

[0262] The portable information terminal 910 shown in FIG. 9(C) has a housing 911, a display portion 912, operation buttons 913 , an external connection port 914, a speaker 915, a microphone 916, a camera 917, etc.

[0263] .

[0264] ​​​The light-emitting device manufactured using one aspect of the present invention can be used for the display unit 912. Thus, a portable information terminal can be manufactured with a high yield.

[0265] The portable information terminal 910 is provided with a touch sensor on the display unit 912. Any operation such as making a call or inputting characters can be performed by touching the display unit 912 with a finger or a stylus.

[0266] Also, by operating the operation button 913, it is possible to turn the power on and off and switch the type of image displayed on the display unit 912. For example, it is possible to switch from the mail creation screen to the main menu screen.

[0267] Also, by providing a detection device such as a gyro sensor or an acceleration sensor inside the portable information terminal 910, it is possible to determine the orientation (portrait or landscape) of the portable information terminal 910 and automatically switch the display orientation of the display unit 912. Also, the switching of the screen display orientation can be performed by touching the display unit 912, operating the operation button 913, or by voice input using the microphone 916.

[0268] The portable information terminal 910 has one or more functions selected from, for example, a telephone, a notebook, or an information browsing device. Specifically, it can be used as a smartphone. The portable information terminal 910 can execute various applications such as a mobile phone, e-mail, text browsing and creation, music playback, video playback, Internet communication, and games.

[0269] The camera 920 shown in FIG. 9(D) includes a housing 921, a display unit 922, an operation button 923, a shutter It has a turbo button 924 and the like. Also, a detachable lens 926 is attached to the camera 920. attached.

[0270] The light-emitting device manufactured using one aspect of the present invention can be used for the display unit 922. By this, a camera with high reliability can be manufactured. By this, a camera with high reliability can be manufactured.

[0271] Here, the camera 920 is configured such that the lens 926 can be removed from the housing 921 and replaced, but the lens 926 and the housing 921 may be integrated. Here, the camera 920 is configured such that the lens 926 can be removed from the housing 921 and replaced, but the lens 926 and the housing 921 may be integrated.

[0272] The camera 920 can capture a still image or a moving image by pressing the shutter button 924. Also, the display unit 922 has a function as a touch panel, and it is also possible to capture an image by touching the display unit 922. The camera 920 can capture a still image or a moving image by pressing the shutter button 924. Also, the display unit 922 has a function as a touch panel, and it is also possible to capture an image by touching the display unit 922. The camera 920 can capture a still image or a moving image by pressing the shutter button 924. Also, the display unit 922 has a function as a touch panel, and it is also possible to capture an image by touching the display unit 922.

[0273] Note that the camera 920 can be separately equipped with a strobe device, a viewfinder, etc. Or, these may be incorporated in the housing 921. Note that the camera 920 can be separately equipped with a strobe device, a viewfinder, etc. Or, these may be incorporated in the housing 921.

[0274] FIG. 10(A) is a schematic diagram showing an example of a cleaning robot.

[0275] The cleaning robot 5100 has a display 5101 arranged on the upper surface, a plurality of cameras 5102 arranged on the side surface, a brush 5103, and operation buttons 5104. Although not shown, the lower surface of the cleaning robot 5100 is provided with tires, a suction port, etc. The cleaning robot 5100 is further provided with various sensors such as an infrared sensor, an ultrasonic sensor, an acceleration sensor, a piezo sensor, a light sensor, and a gyro sensor. Also, the cleaning robot 5100 is provided with wireless communication means. The cleaning robot 5100 has a display 5101 arranged on the upper surface, a plurality of cameras 5102 arranged on the side surface, a brush 5103, and operation buttons 5104. Although not shown, the lower surface of the cleaning robot 5100 is provided with tires, a suction port, etc. The cleaning robot 5100 is further provided with various sensors such as an infrared sensor, an ultrasonic sensor, an acceleration sensor, a piezo sensor, a light sensor, and a gyro sensor. Also, the cleaning robot 5100 is provided with wireless communication means. The cleaning robot 5100 has a display 5101 arranged on the upper surface, a plurality of cameras 5102 arranged on the side surface, a brush 5103, and operation buttons 5104. Although not shown, the lower surface of the cleaning robot 5100 is provided with tires, a suction port, etc. The cleaning robot 5100 is further provided with various sensors such as an infrared sensor, an ultrasonic sensor, an acceleration sensor, a piezo sensor, a light sensor, and a gyro sensor. Also, the cleaning robot 5100 is provided with wireless communication means. The cleaning robot 5100 has a display 5101 arranged on the upper surface, a plurality of cameras 5102 arranged on the side surface, a brush 5103, and operation buttons 5104. Although not shown, the lower surface of the cleaning robot 5100 is provided with tires, a suction port, etc. The cleaning robot 5100 is further provided with various sensors such as an infrared sensor, an ultrasonic sensor, an acceleration sensor, a piezo sensor, a light sensor, and a gyro sensor. Also, the cleaning robot 5100 is provided with wireless communication means. The cleaning robot 5100 has a display 5101 arranged on the upper surface, a plurality of cameras 5102 arranged on the side surface, a brush 5103, and operation buttons 5104. Although not shown, the lower surface of the cleaning robot 5100 is provided with tires, a suction port, etc. The cleaning robot 5100 is further provided with various sensors such as an infrared sensor, an ultrasonic sensor, an acceleration sensor, a piezo sensor, a light sensor, and a gyro sensor. Also, the cleaning robot 5100 is provided with wireless communication means. The cleaning robot 5100 has a display 5101 arranged on the upper surface, a plurality of cameras 5102 arranged on the side surface, a brush 5103, and operation buttons 5104. Although not shown, the lower surface of the cleaning robot 5100 is provided with tires, a suction port, etc. The cleaning robot 5100 is further provided with various sensors such as an infrared sensor, an ultrasonic sensor, an acceleration sensor, a piezo sensor, a light sensor, and a gyro sensor. Also, the cleaning robot 5100 is provided with wireless communication means.

[0276] The cleaning robot 5100 can move automatically, detect dust 5120, and suck up the dust through the suction port provided on the bottom surface.

[0277] In addition, the cleaning robot 5100 can analyze the images captured by the camera 5102 to determine the presence or absence of obstacles such as walls, furniture, or steps. Also, if an object that is likely to get caught in the brush 5103, such as wiring, is detected by image analysis, the rotation of the brush 5103 can be stopped.

[0278] The display 5101 can display the remaining battery level, the amount of dust sucked up, etc. It is also possible to display the path traveled by the cleaning robot 5100 on the display 5101. Further, the display 5101 may be a touch panel, and the operation buttons 5104 may be provided on the display 5101.

[0279] The cleaning robot 5100 can communicate with a portable electronic device 5140 such as a smartphone. The images captured by the camera 5102 can be displayed on the portable electronic device 5140. Therefore, the owner of the cleaning robot 5100 can know the state of the room even when away from home. Also, the display on the display 5101 can be confirmed on a portable electronic device 5140 such as a smartphone.

[0280] The light-emitting device according to one aspect of the present invention can be used for the display 5101.

[0281] The robot 2100 shown in FIG. 10(B) includes an arithmetic unit 2110, an illuminance sensor 2101, a microphone 2102, an upper camera 2103, a speaker 2104, a display 2105. ​​​​​​​​​​​​ It includes a lower camera 2106, an obstacle sensor 2107, and a moving mechanism 2108.

[0282] The microphone 2102 has a function of detecting the user's voice, environmental sounds, etc. Also , the speaker 2104 has a function of emitting sound. The robot 2100 can communicate with the user using the microphone 2102 and the speaker 2104. It is possible.

[0283] The display 2105 has a function of displaying various information. The robot 2100 can display the information desired by the user on the display 2105. The display 2105 may be equipped with a touch panel. Also, the display 2105 may be a removable information terminal, and by installing it at a fixed position of the robot 2100, charging and data transfer are possible.

[0284] The upper camera 2103 and the lower camera 2106 have a function of imaging the surroundings of the robot 2100. Also, the obstacle sensor 2107 can detect the presence or absence of obstacles in the traveling direction when the robot 210 0 moves forward. The robot 21 00 can use the upper camera 2103, the lower camera 2106, and the obstacle sensor 2107 to recognize the surrounding environment and move safely.

[0285] The light-emitting device according to one aspect of the present invention can be used for the display 2105.

[0286] FIG. 10(C) is a diagram showing an example of a goggle-type display. The goggle-type display For example, it includes a housing 5000, a display unit 5001, a speaker 5003, an LED lamp 5004 , operation keys 5005 (including a power switch or an operation switch), connection terminals 5006, a sensor 5007 (including a function for measuring force, displacement, position, speed, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, inclination , vibration, odor, or infrared rays), a microphone 5008, a second display unit 5002, a support unit 5012, earphones 5013, etc.

[0287] The light-emitting device according to one aspect of the present invention can be used for the display unit 5001 and the second display unit 5002. It can be used.

[0288] Also, FIGS. 11(A) and (B) show a foldable portable information terminal 5150. The foldable portable information terminal 5150 has a housing 5151, a display area 5152, and a bending part 515 3. FIG. 11(A) shows the portable information terminal 5150 in an unfolded state. FIG. 11( B) shows the portable information terminal 5150 in a folded state. Despite having a large display area 5152, the portable information terminal 5150 is compact and highly portable when folded.

[0289] The display area 5152 can be folded in half by the bending part 5153. The bending part 515 3 is composed of an extensible member and a plurality of support members. When folding, the extensible member extends, and the bending part 5153 has a curvature radius of 2 mm or more, preferably 5 mm or more and is folded.

[0290] Note that the display area 5152 is a touch panel (input / output It may also be a (device). The light-emitting device according to one aspect of the present invention can be used for the display regions 5152. It is possible.

[0291] This embodiment can be appropriately combined with other embodiments.

[0292] (Embodiment 5) In this embodiment, an example of applying the light-emitting element according to one aspect of the present invention to various lighting devices will be described with reference to FIG. 12. By using the light-emitting element which is one aspect of the present invention, a lighting device with good luminous efficiency and high reliability can be manufactured. By fabricating the light-emitting element according to one aspect of the present invention on a flexible substrate, an electronic device and a lighting device having a light-emitting region with a curved surface can be realized. Moreover, the light-emitting device to which the light-emitting element according to one aspect of the present invention is applied can also be applied to vehicle lighting, and for example, lighting can be installed on the windshield, ceiling, etc.

[0293]

[0294]

[0295] FIG. 12 shows an example in which the light-emitting element is used as an indoor lighting device 8501. Since the light-emitting element can also be made larger in area, a large-area lighting device can be formed. In addition, by using a housing having a curved surface, a lighting device 8502 having a light-emitting region with a curved surface can be formed. The light-emitting element shown in this embodiment is in a thin film shape, and the degree of freedom in the design of the housing is high. Therefore, lighting devices with various designs can be formed. Further, a large lighting device 8503 may be provided on the wall surface of the room. Also, a touch sensor may be provided on the lighting devices 8501, 8502, and 8503 to turn on or off the power supply.

[0296] ​​​​​​​​​​Also, by using the light-emitting element on the surface side of the table, a lighting device 8504 having the function of a table can be obtained. Note that by using the light-emitting element for a part of other furniture, a lighting device having the function of furniture can be obtained.

[0297] As described above, a lighting device and an electronic device can be obtained by applying the light-emitting element of one aspect of the present invention. Note that the applicable lighting devices and electronic devices are not limited to those shown in this embodiment, and can be applied to lighting devices and electronic devices in all fields.

[0298] Also, the configuration shown in this embodiment can be used in appropriate combination with the configuration shown in other embodiments.

Example

[0299] In this example, an example of manufacturing a light-emitting element of one aspect of the present invention will be described. The configuration of the light-emitting element manufactured in this example is the same as that in FIG. 1(A). The details of the element structure are shown in Table 1. Also, the structures and abbreviations of the compounds used are shown below.

[0300]

Chemical formula

[0301]

Table 1

[0302] <Manufacture of the light-emitting element> The manufacturing method of the light-emitting element manufactured in this example is shown below.

[0303] ≪Manufacture of the light-emitting element 1≫ As the electrode 101 on the glass substrate, an ITSO film was formed to a thickness of 70 nm. ​​​​. Note that the electrode area of the electrode 101 was 4 mm 2 (2 mm × 2 mm).

[0304] Next, as a hole injection layer 111 on the electrode 101, DBT3P-II and molybdenum oxide (MoO3) were co-evaporated so that the weight ratio (DBT3P-II:MoO3) was 1:0.5 and the thickness was 30 nm.

[0305] Next, as a hole transport layer 112 on the hole injection layer 111, 9-[3-(9-phenyl-9 H-fluoren-9-yl)phenyl]-9H-carbazole (abbreviation: mCzFLP) was evaporated so that the thickness was 20 nm.

[0306] Next, as a light-emitting layer 130 on the hole transport layer 112, 4-{3-[3’-(9H-carb azole-9-yl)]biphenyl-3-yl}benzofuro[3,2-d]pyrimidine (abbreviation : 4mCzBPBfpm), tris[3-methyl-1-(2-methylphenyl)-5 -phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: Ir(M ptz1-mp)3), and N,N’-bis(4-tert-butylphenyl)-N,N’ -bis〔4-(dibenzofuran-2-yl)phenyl〕-pyrene-1,6-diamine (abbreviation : 1,6tBuFrBAPrn) were co-evaporated so that the weight ratio (4mCzBPBfpm:Ir(Mpt z1-mp)3:1,6tBuFrBAPrn) was 0.8:0.2:0.01 and the thickness was 30 nm. In the light-emitting layer 130, 1,6tB uFrBAPrn is a fluorescent compound and Ir(Mptz1-mp)3 is a phosphorescent compound .

[0307] Next, on the light-emitting layer 130, as the electron transport layer 118, 4mCzBPBfpm was sequentially vapor-deposited to a thickness of 1 5 nm, and NBPhen was vapor-deposited to a thickness of 10 nm. Next, , on the electron transport layer 118, as the electron injection layer 119, LiF was vapor-deposited to a thickness of 1 nm .

[0308] Next, on the electron injection layer 119, as the electrode 102, aluminum (Al) was formed to a thickness of 20 0 nm.

[0309] Next, in a glove box under a nitrogen atmosphere, a glass substrate for sealing was fixed to the glass substrate on which the organic EL sealing material was used to form the organic material, thereby sealing the light-emitting element 1 . Specifically, the sealing material was applied around the organic material formed on the glass substrate, and the glass substrate and the glass substrate for sealing were bonded together, and ultraviolet light with a wavelength of 365 nm was irradiated at 6 J / cm 2 and heat-treated at 80 °C for 1 hour. The light-emitting element 1 was obtained through the above steps.

[0310] ≪Fabrication of Light-Emitting Element 2≫ The light-emitting element 2 is different from the light-emitting element 1 shown above only in the formation process of the light-emitting layer 130, and the other processes were the same as those of the light-emitting element 1.

[0311] As the light-emitting layer 130 of the light-emitting element 2, 4mCzBPBfpm, Ir(Mptz1-mp )3, and 10-acetyl-2,3,6,7-tetrahydro-1,1,7,7-tetramethyl r-1H,5H,11H-[1]benzopyrano[6,7,8-ij]quinolizin-11- one (abbreviation: coumarin521T), and the weight ratio (4mCzBPBfpm:Ir( Mptz1-mp)3:coumarin521T) was 0.8:0.2:0.005 co-evaporated so as to have a thickness of 30 nm. In the light-emitting layer 130, co umarin521T is a fluorescent compound that is the third organic compound, and Ir(Mptz1 -mp)3 is a phosphorescent compound.

[0312] <Characteristics of the light-emitting device> Next, the characteristics of the fabricated light-emitting devices 1 and 2 were measured. For the measurement of luminance and CIE color coordinates, a color luminance meter (Topcon Corporation, BM-5A) was used, and for the measurement of the electroluminescence spectrum, a multi-channel spectroscope (Hamamatsu Photonics, PMA-11) was used.

[0313] The current efficiency-luminance characteristics of the light-emitting devices 1 and 2 are shown in FIG. 13, the current-voltage characteristics are shown in FIG. 14 and the external quantum efficiency-luminance characteristics are shown in FIG. 15, respectively. Also, for the light-emitting devices 1 and 2, the electroluminescence spectra when a current was passed at a current density of 2.5 mA / cm are shown in FIG. 16. The measurement of each light-emitting device was performed at room temperature (an atmosphere maintained at 23°C). 2

[0314] Also, the device characteristics of the light-emitting devices 1 and 2 in the vicinity of 1000 cd / m 2 are shown in Table 2.

[0315]

Table 2

[0316] From FIG. 16, the emission spectra of the light-emitting devices 1 and 2 have peak wavelengths of 4 87 nm and 480 nm, respectively, and show blue emission derived from the fluorescent compounds 1,6tBuFrBAPrn and cou marin521T. Also, the light-emitting element which is one aspect of the present invention The light-emitting element 1 and the light-emitting element 2 exhibit light emission with a small full width at half maximum of the electroluminescence spectrum and high color purity. Therefore, they are suitable for display devices.

[0317] Also, as shown in FIGS. 13, 15 and Table 2, the light-emitting element 1 and the light-emitting element 2 exhibit high luminous efficiency (current efficiency, power efficiency, and external quantum efficiency). Here, since the generation probability of singlet excitons generated by the recombination of carriers (holes and electrons) injected from a pair of electrodes is at most 25%, when the external light extraction efficiency is 25%, the external quantum efficiency is at most 6.25%. In the light-emitting element 1 and the light-emitting element 2, an efficiency higher than 6. 25% is obtained. This is because in the light-emitting element 1 and the light-emitting element 2 according to one aspect of the present invention, in addition to light emission derived from singlet excitons, triplet excitons can be contributed to fluorescence emission as singlet excitons by passing through Ir(Mptz1-mp)3 which is a phosphorescent compound.

[0318] Also, the light-emitting element 1 and the light-emitting element 2 have little decrease in efficiency on the high brightness side (also referred to as roll-off). Thus, the point of having little roll-off is one of the characteristics of the light-emitting element of one aspect of the present invention.

[0319] Also, an organic compound having a benzofuropyrimidine skeleton such as 4mCzBPBfpm used as the host material of the light-emitting element 1 and the light-emitting element 2 has high S1 level and T1 level. Therefore it is possible to obtain a highly efficient light-emitting element that exhibits blue fluorescence like the light-emitting element 1 and the light-emitting element 2.

Examples

[0320] In this example, a production example of a light-emitting element and a comparative light-emitting element according to one aspect of the present invention will be described. In this example, the configuration of the produced light-emitting element is the same as that in FIG. 1(A). The details of the element structure are shown in Table 3. In addition, the structures and abbreviations of the compounds used are shown below. For the structures and abbreviations of other compounds, Example 1 may be referred to.

[0321] [Chemical formula]

[0322] [Table 3]

[0323] [Production of light-emitting element] The production method of the light-emitting element produced in this example is shown below.

[0324] [Production of light-emitting element 3] As electrode 101 on a glass substrate, an ITSO film was formed to a thickness of 70 nm. The electrode area of electrode 101 was 4 mm 2 (2 mm × 2 mm).

[0325] Next, as hole injection layer 111 on electrode 101, DBT3P-II and molybdenum oxide (MoO3) were co-evaporated so that the weight ratio (DBT3P-II:MoO3) was 1:0.5 and the thickness was 40 nm.

[0326] Next, as hole transport layer 112 on hole injection layer 111, 9-[3-(9-phenyl-9 H-fluoren-9-yl)phenyl]-9H-carbazole (abbreviation: mCzFLP) was evaporated to a thickness of 20 nm.

[0327] Next, as the light-emitting layer 130 on the hole transport layer 112, 4mCzBPBfpm, tris 2-(1H-pyrazol-1-yl-κN 2 )phenyl-κC]iridium(III)( (abbreviation: Ir(ppz)3), and 10-(2-benzothiazolyl)-2,3,6,7-tet rahydro-1,1,7,7-tetramethyl-1H,5H,11H-[1]benzopyrano 6,7,8-ij]quinolizin-11-one (abbreviation: coumarin545T) were co-evaporated so that the weight ratio (4mCzBPBfpm:Ir(ppz)3:coumarin545T) was 0. 8:0.2:0.005 and the thickness was 30 nm. In the light-emitting layer 130, coumarin545T is a fluorescent compound.

[0328] Next, on the light-emitting layer 130, as the electron transport layer 118, 4mCzBPBfpm was sequentially evaporated so that the thickness became 1 5 nm and the thickness of NBPhen became 20 nm. Next , on the electron transport layer 118, as the electron injection layer 119, LiF was evaporated so that the thickness became 1 nm .

[0329] Next, on the electron injection layer 119, as the electrode 102, aluminum (Al) was formed so that the thickness became 20 0 nm.

[0330] Next, in a glove box under a nitrogen atmosphere, a glass substrate for sealing was fixed to the glass substrate on which the organic material was formed using an organic EL sealing material, thereby sealing the light-emitting element 3 . Specifically, a sealing material was applied around the organic material formed on the glass substrate, and the glass substrate and the glass substrate for sealing were bonded together, and ultraviolet light with a wavelength of 365 nm was irradiated at 6 J / cm 2It was irradiated and heat-treated at 80 °C for 1 hour. The light-emitting element 3 was obtained through the above steps.

[0331] ≪Fabrication of Comparative Light-Emitting Element 4≫ Comparative light-emitting element 4 is different from the light-emitting element 3 shown above only in the formation process of the light-emitting layer 130, and the other processes were carried out in the same manufacturing method as that of the light-emitting element 3.

[0332] As the light-emitting layer 130 of the comparative light-emitting element 4, 4mCzBPBfpm and Ir(ppz)3 were co-evaporated so that the weight ratio (4mCzBPBfpm:Ir(ppz)3) was 0.8:0.2 and the thickness was 30 nm. Compared with the light-emitting layer 130 of the light-emitting element 3, the light-emitting layer 130 of the comparative light-emitting element 4 does not contain the fluorescent compound coumarin545T.

[0333] ≪Fabrication of Comparative Light-Emitting Element 5≫ Comparative light-emitting element 5 is different from the light-emitting element 3 shown above only in the formation processes of the light-emitting layer 130 and the electron transport layer 118, and the other processes were carried out in the same manufacturing method as that of the light-emitting element 3.

[0334] On the hole transport layer 112, as the light-emitting layer 130, 4,6mCzP2Pm, Ir(ppz) 3, and coumarin545T were co-evaporated so that the weight ratio (4,6mCzP2Pm:Ir(ppz) 3:coumarin545T) was 0.8:0.2:0.005 and the thickness was 30 nm. In the light-emitting layer 130, coumarin545 T is a fluorescent compound that serves as the third organic compound. Note that in the light-emitting layer 130 of the comparative light-emitting element 5, 4,6mCzP2Pm having a pyrimidine skeleton is used as the host material, but the other configurations are the same as those of the light-emitting element 3.

[0335] ​Next, on the light-emitting layer 130, as the electron transport layer 118, 4,6mCzP2Pm was sequentially vapor-deposited to a thickness of 1 5 nm, and BPhen was vapor-deposited to a thickness of 20 nm. Next, on the electron transport layer 118, as the electron injection layer 119, LiF was vapor-deposited to a thickness of 1 nm onto it.

[0336] <Characteristics of the light-emitting element> Next, the characteristics of the fabricated light-emitting element 3, comparative light-emitting element 4, and comparative light-emitting element 5 were measured . The measurement method was the same as in Example 1.

[0337] The current efficiency-luminance characteristics of the light-emitting element 3, comparative light-emitting element 4, and comparative light-emitting element 5 are shown in Fig. 17, the current-voltage characteristics are shown in Fig. 18, and the external quantum efficiency-luminance characteristics are shown in Fig. 19, respectively. Also, the electroluminescence spectra when a current was passed through the light-emitting element 3, comparative light-emitting element 4, and comparative light-emitting element 5 at a current density of 2.5 mA / cm are shown in Fig. 20. The measurement of each light-emitting element was performed at room temperature (in an atmosphere maintained at 23 °C). Moreover, the element characteristics of the light-emitting element 3, comparative light-emitting element 4, and comparative light-emitting element 5 in the vicinity of 1000 cd / m 2 are shown in Table 4. As shown in Fig. 20, the electroluminescence spectra of the light-emitting element 3 and comparative light-emitting element 5 showed green light with peak wavelengths of 512 nm and full widths at half maximum of about 63 nm, respectively. Therefore, the light emitted by the light-emitting element 3 and comparative light-emitting element 5 is fluorescence from the fluorescent compound coumar

[0338] Also, 2 near the element characteristics of the light-emitting element 3, comparative light-emitting element 4, and comparative light-emitting element 5 are shown in Table 4.

[0339]

Table 4

[0340] As shown in Fig. 20, the electroluminescence spectra of the light-emitting element 3 and comparative light-emitting element 5 showed green light with peak wavelengths of 512 nm and full widths at half maximum of about 63 nm, respectively. Therefore, the light emitted by the light-emitting element 3 and comparative light-emitting element 5 is fluorescence from the fluorescent compound coumar Thus, the light emitted by the light-emitting element 3 and the comparative light-emitting element 5 is fluorescence from the fluorescent compound coumar It is luminescence derived from in545T. Note that Ir used for the light-emitting element 3 and the comparative light-emitting element 5 (ppz)3 is a compound that emits blue light at low temperatures and no luminescence is observed at room temperature, and it is known that, but luminescence derived from Ir(ppz)3 was not observed.

[0341] Also, the electroluminescence spectrum of the comparative light-emitting element 4 had a peak wavelength of 532 nm and a full width at half maximum showing a wide spectral shape of 83 nm. The luminescence exhibited by the comparative light-emitting element 4 is, as will be shown later, luminescence derived from an exciplex formed by 4mCzBPBfpm and Ir(ppz)3. Thus, the light-emitting element 3, which is one aspect of the present invention, exhibits electroluminescence with a shorter peak wavelength and a smaller full width at half maximum in the electroluminescence spectrum than the comparative light-emitting element 4, and has high color purity. Therefore, the light-emitting element of one aspect of the present invention is suitable for a display device.

[0342] Also, as shown in FIGS. 17 and 19 and Table 4, the light-emitting element 3, the comparative light-emitting element 4, and the comparative light-emitting element 5 exhibit high luminous efficiency (current efficiency, power efficiency, and external quantum efficiency). Also, the light-emitting element 3 has an external quantum efficiency higher than 6.25%. This is in addition to luminescence derived from singlet excitons generated by the recombination of carriers (holes and electrons), luminescence derived from triplet excitons, or luminescence derived from singlet excitons generated from triplet excitons by reverse intersystem crossing in the exciplex. The comparative light-emitting element 4 is luminescence derived from an exciplex, and the light-emitting element 3 is a light-emitting element of one aspect of the present invention that utilizes ExEF.

[0343] <Time-resolved luminescence measurement> Next, time-resolved luminescence measurements were performed on the light-emitting element 3 and the comparative light-emitting element 4.

[0344] The measurements were performed using a picosecond fluorescence lifetime measurement system (Hamamatsu Photonics). In order to measure the lifetime of the fluorescent light emitted from the light-emitting element, a rectangular pulse voltage is applied to the light-emitting element, The decaying light emission from the voltage drop was measured in time resolution using a streak camera. The pulse voltage is applied at a frequency of 10 Hz, and the S The data obtained was of a high / N ratio. The measurements were performed at room temperature (300K), and the luminance of the light-emitting element was 100 0 cd / m 2 Apply a pulse voltage of around 3V to 4V so that the Interval: 100μsec, negative bias voltage: -5V (when element drive is OFF), measurement time range The measurement results are shown in FIG. 21. In FIG. 21, is the emission intensity when carriers are constantly being injected (when the pulse voltage is ON). The intensity is shown as a normalized value, and the horizontal axis indicates the time elapsed from the fall of the pulse voltage.

[0345] As shown in FIG. 21, the light-emitting element 3 has a slower light-emission decay rate than the comparative light-emitting element 4. This means that the excitation energy is rapidly converted into light emission. In the light-emitting layer, the exciton density is high (a large amount of current is flowing). Therefore, as shown in Figs. 17 and 19, The optical element 3 has a small roll-off. Thus, the small roll-off is one aspect of the present invention. This is one of the characteristics of the light-emitting device.

[0346] <CV測定結果> Next, the electrochemical properties (oxidation and reduction properties) of the above compounds were examined by cycling. It was measured by cyclic voltammetry (CV) measurement. In the measurement, an electrochemical analyzer -(manufactured by BAS Inc., model number: ALS model 600A or 600C) was used, and a solution in which each compound was dissolved in N,N-dimethylformamide (abbreviation: DMF) was measured. In the measurement, the potential of the working electrode with respect to the reference electrode was changed within an appropriate range to obtain the oxidation peak potential and the reduction peak potential, respectively. Also, since the redox potential of the reference electrode is estimated to be -4.9 4 eV, the HOMO level and LUMO level of each compound were calculated from this value and the obtained peak potential.

[0347] The HOMO level of Ir(ppz)3 calculated from CV measurement was -5.39 eV, and the LUMO level was -1.77 eV. Also, the HOMO level of 4mCzBPBfpm was -5.91 e V, and the LUMO level was -2.97 eV. Also, the HOMO level of 4,6mCzP2Pm was -5.89 eV, and the LUMO level was -2.88 eV.

[0348] As described above, the LUMO level of 4mCzBPBfpm is lower than the LUMO level of Ir(ppz)3, and the HOMO level of Ir(ppz)3 is higher than the HOMO level of 4mCzBPBfpm. Therefore, when the compound is used in the light-emitting layer as in the light-emitting device 3 and the comparative light-emitting device 4, electrons and holes, which are carriers injected from a pair of electrodes, are efficiently injected into 4m CzBPBfpm and Ir(ppz)3, respectively, and an exciplex can be formed between 4mCzBPBfpm and Ir (ppz)3. Similarly, an exciplex can be formed between 4,6mCzP2Pm and Ir (ppz)3. Therefore, the comparative light-emitting device 5 is also a light-emitting device that utilizes ExE F. ​

[0349] In addition, the exciplex formed by 4mCzBPBfpm and Ir(ppz)3 is such that 4mCzB PBfpm has the LUMO level and Ir(ppz)3 has the HOMO level of the exciplex. Moreover, the energy difference between the LUMO level of 4mCzBPBfpm and the HOMO level of Ir(ppz)3 is 2.42 eV. This value is approximately consistent with the emission energy (2.33 eV) calculated from the peak wavelength of the emission spectrum of the comparative light-emitting device 4 shown in FIG. 20. Therefore, it can be said that the emission spectrum of the comparative light-emitting device 4 is emission based on the exciplex formed by 4mCzBPBfpm and Ir(ppz)3. Note that since the difference between the S1 level and the T1 level of the exciplex is small, the emission energy can be regarded as the energy of the S1 level and the T1 level (2.33 eV) of the exciplex. 1 level (2.33 eV).

[0350] <Relationship between the emission spectrum of the exciplex and the absorption spectrum of the guest material> In addition, FIG. 22 shows the results of measuring the absorption spectrum of coumarin545T in a toluene solution. Also, in accordance with FIG. 22, the emission spectrum of the exciplex exhibited by the comparative light-emitting device 4 is shown. Note that for the measurement of the absorption spectrum, an ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, model V550) was used, and the measurement was performed at room temperature (in an atmosphere maintained at 23°C).

[0351] As shown in FIG. 22, there is a region where the absorption spectrum of coumarin545T and the emission spectrum of the exciplex exhibited by the comparative light-emitting device 4 overlap. Therefore, from the exciplex formed by 4mCzBPBfpm and Ir(ppz)3, coumarin, which is a fluorescent compound m and Ir(ppz)3, the fluorescent compound coumarin It is possible to efficiently supply excitation energy to 545T. With this configuration, As in the electroluminescence spectrum of the light-emitting element 3 shown in FIG. 20, an electroluminescence spectrum of an exciplex it is possible to provide a light-emitting element that exhibits light emission having a peak wavelength shorter than the peak wavelength of .

[0352] <Measurement of T1 level> Next, in order to determine the T1 level of the compound used in the light-emitting layer 130, a thin film of 4mCzBPBfpm was formed on a quartz substrate by vacuum evaporation method, and the emission spectrum of the thin film was measured at low temperature (10K) . For the measurement, a microscopic PL apparatus LabRAM HR-PL (manufactured by Horiba, Ltd. ) was used, the measurement temperature was 10K, a He-Cd laser with a wavelength of 325 nm was used as the excitation light , and a CCD detector was used as the detector.

[0353] As a result, the T1 level of 4mCzBPBfpm was calculated to be 2.68 eV.

[0354] In addition, in order to estimate the T1 level of Ir(ppz)3, the absorption spectrum and the emission spectrum were measured. A dichloromethane solution in which Ir(ppz)3 was dissolved was prepared, and the absorption spectrum was measured using a quartz cell . For the measurement of the absorption spectrum, an ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, V550 type) was used. The absorption spectra of the quartz cell and the solvent were subtracted from the absorption spectrum of the measured sample. The measurement was performed at room temperature (atmosphere maintained at 23°C) .

[0355] From the data of the absorption spectrum described above, the absorption edge was obtained, and as a result of estimating the transition energy assuming a direct transition , the transition energy of Ir(ppz)3 was calculated to be 3.27 eV. I Since r(ppz)3 is a phosphorescent compound, the absorption edge on the lowest energy side is an absorption band based on the transition from the triplet excited state. Therefore, the T1 level of Ir(ppz)3 is calculated to be 3.27 eV higher than the absorption edge.

[0356] From the above measurement results, the T1 level of 4mCzBPBfpm is lower than the T1 level of Ir(ppz)3, and the T1 level of 4mCzBPBfpm is higher than the T1 level of the exciplex formed by 4mCzBPBfpm and Ir(ppz )3 (2.33 eV). Therefore, the triplet excitation energy of the exciplex formed by 4mCz BPBfpm and Ir(ppz)3 will not be deactivated by 4mCz BPBfpm and Ir(ppz)3 respectively. Therefore, the triplet excitation energy of the exciplex can be converted into singlet excitation energy by reverse intersystem crossing to be converted into light emission, or can transfer energy to a fluorescent compound.

[0357] Also, when attempting to measure the emission spectrum of Ir(ppz)3 at room temperature, no emission of Ir(ppz )3 was observed. Non-Patent Document 1 describes that the emission quantum yield of Ir(ppz)3 is less than 1% at room temperature. From this, it can be seen that Ir(ppz)3 is a material that does not emit light at room temperature. That is, even when using a compound with a low emission quantum yield of less than 1%, a light-emitting device having high luminous efficiency can be obtained.

[0358] <Reliability of the light-emitting device> Fig. 23 shows the constant current drive test results at 0.5 mA of the light-emitting device 3, the comparative light-emitting device 4, and the comparative light-emitting device 5. From Fig. 23, the light-emitting device 3 is more than the comparative light-emitting device 4 and the comparative light-emitting device 5 It was found to have good reliability. The difference between the light-emitting element 3 and the comparative light-emitting element 4 is the presence or absence of a fluorescent compound. As described above, light emission from the fluorescent compound is obtained from the light-emitting element 3, and light emission from the exciplex is obtained from the comparative light-emitting element 4. Therefore, as in the light-emitting element of one aspect of the present invention, it was found that obtaining light emission from a fluorescent compound has better reliability. Also, the difference between the light-emitting element 3 and the comparative light-emitting element 5 is the difference in the host material. As described above, a material having a benzofuropyrimidine skeleton is used as the host material for the light-emitting element 3, and a material having a pyrimidine skeleton is used as the host material for the comparative light-emitting element 5. Therefore, by using a material having a benzofuropyrimidine skeleton, a light-emitting element having high reliability can be obtained. It is the presence or absence of a fluorescent compound. As described above, light emission from the fluorescent compound is obtained from the light-emitting element 3, and light emission from the exciplex is obtained from the comparative light-emitting element 4. Therefore, as in the light-emitting element of one aspect of the present invention, it was found that obtaining light emission from a fluorescent compound has better reliability. Also, the difference between the light-emitting element 3 and the comparative light-emitting element 5 is the difference in the host material. As described above, a material having a benzofuropyrimidine skeleton is used as the host material for the light-emitting element 3, and a material having a pyrimidine skeleton is used as the host material for the comparative light-emitting element 5. Therefore, by using a material having a benzofuropyrimidine skeleton, a light-emitting element having high reliability can be obtained. a material having a benzofuropyrimidine skeleton is used as the host material for the light-emitting element 3, and a material having a pyrimidine skeleton is used as the host material for the comparative light-emitting element 5. Therefore, by using a material having a benzofuropyrimidine skeleton, a light-emitting element having high reliability can be obtained. It is possible to obtain a light-emitting element having high reliability.

[0359] As described above, according to one aspect of the present invention, a light-emitting element having high luminous efficiency and good reliability can be provided. Also, according to one aspect of the present invention, a light-emitting element having a low driving voltage and low power consumption can be provided.

Example

[0360] In this example, an example of manufacturing a light-emitting element of one aspect of the present invention and a comparative light-emitting element will be described. The configuration of the light-emitting element manufactured in this example is the same as that in FIG. 1(A). The details of the element structure are shown in Table 5. The details of the element structure are shown in Table 5. Also, the structures and abbreviations of the compounds used are shown below. For the structures and abbreviations of other compounds, refer to Example 1.

[0361]

Chemical formula

[0362]

Table 5

[0363] <Fabrication of Light-Emitting Element> The fabrication method of the light-emitting element fabricated in this example is shown below.

[0364] ≪Fabrication of Light-Emitting Element 6≫ On a glass substrate, an ITSO film was formed as electrode 101 to a thickness of 70 nm . The electrode area of electrode 101 was 4 mm 2 (2 mm × 2 mm).

[0365] Next, as a hole injection layer 111 on electrode 101, DBT3P-II and molybdenum oxide (MoO3) were co-evaporated so that the weight ratio (DBT3P-II:MoO3) was 1:0.5 and to a thickness of 45 nm.

[0366] Next, as a hole transport layer 112 on the hole injection layer 111, 4,4'-diphenyl-4'' -(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCB Bi1BP) was vapor-deposited to a thickness of 20 nm.

[0367] Next, as a light-emitting layer 130 on the hole transport layer 112, 4,8-bis[3-(dibenzothio phen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 4 ,8mDBtP2Bfpm) and 9-phenyl-9H-3-(9-phenyl-9H-carb azole-3-yl)carbazole (abbreviation: PCCP), [2-(4-phenyl-2-py ridinyl-κN)phenyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC iridium(III) (abbreviation: Ir(ppy)2(4dppy)), and 2,8-di-t ert-butyl-5,11-bis(4-tert-butylphenyl)-6,12-diphe Nile tetracene (abbreviation: TBRb) and, with a weight ratio (4,8mDBtP2Bfpm:PCC P:Ir(ppy)2(4dppy):TBRb) of 0.6:0.4:0.1:0.01 were co-evaporated so as to achieve these ratios and with a thickness of 40 nm. In the light-emitting layer 130, TBRb is a fluorescent compound.

[0368] Next, on the light-emitting layer 130, as the electron transport layer 118, 4,8mDBtP2Bfpm was deposited with a thickness of 20 nm and NBPhen was deposited with a thickness of 10 nm in sequence. Next, on the electron transport layer 118, as the electron injection layer 119, LiF was deposited with a thickness of 1 nm as such.

[0369] Next, on the electron injection layer 119, as the electrode 102, aluminum (Al) was formed with a thickness of 20 0 nm.

[0370] Next, in a glove box under a nitrogen atmosphere, a glass substrate for sealing was fixed to the glass substrate on which the organic material was formed using an organic EL sealing material, thereby sealing the light-emitting element 6 Specifically, the sealing material was applied around the organic material formed on the glass substrate, and the glass substrate and the glass substrate for sealing were bonded together, irradiated with ultraviolet light having a wavelength of 365 nm at 6 J / cm 2 and heat-treated at 80 °C for 1 hour. The light-emitting element 6 was obtained through the above steps.

[0371] ≪Fabrication of Comparative Light-Emitting Element 7≫ Comparative light-emitting element 7 differed only in the formation process of the light-emitting layer 130 from the light-emitting element 6 shown above, and the other processes were the same as those for the light-emitting element 6.

[0372] As the light-emitting layer 130 of the comparative light-emitting element 7, 4,8mDBtP2Bfpm, PCCP, and Ir(ppy)2(4dppy) were co-evaporated so that the weight ratio (4,8mDBtP2Bfpm:PCCP:I r(ppy)2(4dppy)) was 0.6:0.4:0.1 and the thickness was 4 0 nm. Compared with the light-emitting layer 130 of the light-emitting element 6, the light-emitting layer of the comparative light-emitting element 7 does not contain TBRb, which is a fluorescent compound.

[0373] ≪Fabrication of Comparative Light-Emitting Element 8≫ Comparative light-emitting element 8 differed only in the process of forming the light-emitting layer 130 and the electron transport layer 118 from the light-emitting element 6 shown above, and the other processes were the same as those of the light-emitting element 6.

[0374] As the light-emitting layer 130 of the comparative light-emitting element 8, 4,6-bis[3-(dibenzothiophen-4 -yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), PCCP, and Ir(ppy)2(4dppy), and TBRb were co-evaporated so that the weight ratio (4,6mDBTP2Pm-I I:PCCP:Ir(ppy)2(4dppy):TBRb) was 0.6:0.4:0.1 :0.01 and the thickness was 40 nm. Compared with the light-emitting layer 130 of the light-emitting element 6, a compound having a pyrimidine skeleton was used as the host material in the light-emitting layer 130 of the comparative light-emitting element 8.

[0375] Next, on the light-emitting layer 130, as the electron transport layer 118, 4,6mDBTP2Pm-II was evaporated sequentially so that the thickness was 20 nm and the thickness of NBPhen was 10 nm.

[0376] <Characteristics of Light-Emitting Element> Next, the characteristics of the above-prepared light-emitting element 6, comparative light-emitting element 7, and comparative light-emitting element 8 were measured. Note that the measurement method is the same as that in Example 1.

[0377] The current efficiency-luminance characteristics of the light-emitting element 6, comparative light-emitting element 7, and comparative light-emitting element 8 are shown in FIG. 24, the current-voltage characteristics are shown in FIG. 25, and the external quantum efficiency-luminance characteristics are shown in FIG. 26, respectively. Also, the electroluminescence spectra of the light-emitting element 6, comparative light-emitting element 7, and comparative light-emitting element 8 when a current was passed at a current density of 2.5 mA / cm are shown in FIG. 27. Note that the measurement of each light-emitting element was performed at room temperature (atmosphere maintained at 23°C). Also, the device characteristics of the light-emitting element 6, comparative light-emitting element 7, and comparative light-emitting element 8 in the vicinity of 1000 cd / m 2 are shown in Table 6. Note that the measurement of each light-emitting element was performed at room temperature (atmosphere maintained at 23°C). Note that the measurement of each light-emitting element was performed at room temperature (atmosphere maintained at 23°C).

[0378] Also, the device characteristics of the light-emitting element 6, comparative light-emitting element 7, and comparative light-emitting element 8 in the vicinity of 1000 cd / m 2 are shown in Table 6. Note that the measurement of each light-emitting element was performed at room temperature (atmosphere maintained at 23°C).

[0379]

Table 6

[0380] As shown in FIG. 27, the electroluminescence spectra of the light-emitting element 6 and the comparative light-emitting element 8 showed yellow emission with peak wavelengths of 563 nm and full widths at half maximum of about 72 nm, respectively. Therefore, the emission exhibited by the light-emitting element 6 and the comparative light-emitting element 8 is emission derived from the fluorescent compound TBRb. Note that no emission derived from Ir(ppy)2(4d py) was observed from the light-emitting element 6 and the comparative light-emitting element 8. Also, the emission spectrum of the comparative light-emitting element 7 showed a broad spectrum shape with a peak wavelength of 557 nm and a full width at half maximum of 80 nm. The emission exhibited by the comparative light-emitting element 7 is emission derived from Ir(pp

[0381] Also, the emission spectrum of the comparative light-emitting element 7 showed a broad spectrum shape with a peak wavelength of 557 nm and a full width at half maximum of 80 nm. The emission exhibited by the comparative light-emitting element 7 is emission derived from Ir(pp y)2(4dpy)-derived emission. Thus, the light-emitting element according to one aspect of the present invention 6 has a smaller full width at half maximum of the electroluminescence spectrum and higher color purity than the comparative light-emitting element 7, and can exhibit such emission. Therefore, one aspect of the present invention is suitable for a display device.

[0382] Also, as shown in FIGS. 24 and 26 and Table 6, the light-emitting element 6, the comparative light-emitting element 7, and the comparative light-emitting element 8 exhibit very high luminous efficiency (current efficiency, power efficiency, and external quantum efficiency). Moreover, the light-emitting element 6 has a very high efficiency with an external quantum efficiency far exceeding 6.25%. This is because, in addition to the emission derived from singlet excitons generated by the recombination of carriers (holes and electrons), emission derived from triplet excitons is obtained. This indicates that excitation energy is transferred from the phosphorescent material Ir(ppy)2(4dppy) to the fluorescent compound TBRb. In addition, since the light-emitting element 6 exhibits a higher external quantum efficiency than the comparative light-emitting element 7, it can be seen that the deactivation of excitation energy is suppressed and the excitation energy can be efficiently converted into emission. Furthermore, the light-emitting element 6 has little roll-off. Thus, the property of having little roll-off is one of the characteristics of the light-emitting element according to one aspect of the present invention.

[0383]

[0384]

[0385] <CV measurement results> Next, the HOMO level and the LUMO level were calculated by cyclic voltammetry (CV) measurement of the electrochemical properties (oxidation reaction properties and reduction reaction properties) of the above compounds. The measurement method was the same as in Example 2 shown above.

[0385] ​​From CV measurement, the HOMO level of 4,8mDBtP2Bfpm is -6.18 eV, and the LUMO level is -3.02 eV. The HOMO level of PCCP is -5.63 eV, and the LUMO level is -1 .96 eV. Also, the HOMO level of 4,6mDBTP2Pm-II is -6.22 eV, and the LUMO level is -2.83 eV.

[0386] Therefore, 4,8mDBtP2Bfpm has a higher HOMO level and a lower LUMO level than PCCP. Thus, 4,8mDBtP2Bfpm and PCCP are a combination that forms an exciplex in the light-emitting layer. Similarly, 4,6mDBTP2Pm-II and PCC P are also a combination that forms an exciplex.

[0387] Moreover, the S1 level and T1 level calculated from the emission energy calculated from the peak wavelength of the emission spectrum of the exciplex formed from 4,8mDBtP2Bfpm and PCCP are 2.6 1 eV. Here, the T1 level of Ir(ppy)2(4dpy) is 2.40 eV (calculated from the absorption edge of the dichloro methane solution). Therefore, both the singlet excitation energy and the triplet excitation energy of the exciplex can move to Ir(ppy)2(4dpy).

[0388] <Relationship between the emission spectrum of the exciplex and the absorption spectrum of the guest material> Also, Fig. 28 shows the result of measuring the absorption spectrum of TBRb in a toluene solution. Also, in accordance with Fig. 28, the emission spectrum exhibited by the comparative light-emitting device 7 is shown. The measurement was performed in the same manner as in the examples shown above.

[0389] As shown in Fig. 28, the absorption spectrum of TBRb and the emission spectrum exhibited by the comparative light-emitting device 7 ​​​​It has an area where torrs overlap. Therefore, it is formed by 4,8mDBtP2Bfpm and PCCP From the exciplex formed by and PCCP, through Ir(ppy)2(4dpy), the fluorescent compound TBRb It is possible to efficiently transfer excitation energy to. The phosphorescent compound Ir(pp Energy transfer occurs to TBRb through y)2(4dpy), and by this, triplet excitation Energy can contribute to fluorescence emission. Note that a similar mechanism occurs in the comparative light-emitting device 8 Can also occur.

[0390] Here, the light-emitting device 6 has better luminous efficiency than the comparative light-emitting device 8. Here, the difference between the two Is the host material. The light-emitting device 6 uses a material having a benzofuropyrimidine skeleton for comparison The light-emitting device 8 uses a material having a pyrimidine skeleton respectively. Therefore, by using a material having a benzofuropyrimidine skeleton as the host material A light-emitting device with better luminous efficiency can be obtained.

[0391] <Reliability of the light-emitting device> Next, for the light-emitting device 6, the comparative light-emitting device 7, and the comparative light-emitting device 8, a constant current drive test was conducted at 2 mA . Table 7 shows the LT 40 (Luminance 60% decay time) of these light-emitting devices.

[0392]

Table 7

[0393] From Table 7, the light-emitting device 6, which is a light-emitting device of one aspect of the present invention, showed the best reliability. The difference between the light-emitting Device 6 and the comparative light-emitting device 7 is the presence or absence of a fluorescent compound. Therefore, it is shown that the reliability is improved by the occurrence of energy transfer from the phosphorescent material To the fluorescent material through. It is urged. Also, the light-emitting element 6 has better reliability than the comparative light-emitting element 8. Therefore Similar to Example 2, it was found that a light-emitting element with good reliability can be obtained by using a material having a benzofuropyrimidine skeleton.

Explanation of Symbols

[0394] 100 EL layer 101 Electrode 102 Electrode 106 Light-emitting unit 108 Light-emitting unit 111 Hole injection layer 112 Hole transport layer 113 Electron transport layer 114 Electron injection layer 115 Charge generation layer 116 Hole injection layer 117 Hole transport layer 118 Electron transport layer 119 Electron injection layer 120 Light-emitting layer 130 Light-emitting layer 131 Compound 132 Compound 133 Compound 134 Compound 150 Light-emitting element 170 Light-emitting layer 250 Light-emitting element 601 Source-side drive circuit 602 Pixel section 603 Gate-side drive circuit 604 Encapsulation substrate 605 Sealing material 607 Space 608 Wiring 609 FPC 610 Element substrate 611 Switching TFT 612 Current control TFT 613 Electrode 614 Insulator 616 EL layer 617 Electrode​ 618 Light-emitting element 623 n-channel type TFT 624 p-channel type TFT 625 Drying material 900 Portable information terminal 901 Housing 902 Housing 903 Display unit 905 Hinge part 910 Portable information terminal 911 Housing 912 Display unit 913 Operation button 914 External connection port 915 Speaker 916 Microphone 917 Camera 920 Camera 921 Housing 922 Display unit 923 Operation button 924 Shutter button 926 Lens 1001 Substrate 1002 Underlying insulating film 1003 Gate insulating film 1006 Gate electrode 1007 Gate electrode 1008 Gate electrode 1020 Interlayer insulating film 1021 Interlayer insulating film 1022 Electrode 1024B Electrode 1024G Electrode 1024R Electrode 1024W Electrode 1025B Lower electrode 1025G Lower electrode 1025R Lower electrode 1025W Lower electrode 1026 Partition wall 1028 EL layer 1029 Electrode 1030 Black layer 1031 Sealing substrate 1032 Sealing material 1033 Base material 1034B Coloring layer 1034G Coloring layer 1034R Coloring layer 1035 Black layer 1036 Overcoat layer 1037 Interlayer insulating film 1040 Pixel section 1041 Driving circuit section 1042 Peripheral section 1044B Blue pixel 1044G Green pixel 1044R Red pixel 1044W White pixel 2100 Robot 2101 Illuminance sensor 2102 Microphone 2103 Upper camera 2104 Speaker 2105 Display 2106 Lower camera 2107 Obstacle sensor 2108 Moving mechanism 2110 Arithmetic unit 5000 Housing 5001 Display section 5002 Display section 5003 Speaker 5004 LED lamp 5005 Operation key 5006 Connection terminal 5007 Sensor 5008 Microphone 5012 Support section 5013 Earphone 5100 Cleaning robot 5101 Display 5102 Camera 5103 Brush 5104 Operation button 5120 Dust 5140 Portable electronic device 5150 Portable information terminal 5151 Housing 5152 Indicating area 5153 Bending part 8501 Lighting device 8502 Lighting device 8503 Lighting device 8504 Lighting device

Claims

[Claim 1] A light-emitting layer is disposed between a pair of electrodes, the light-emitting layer includes a first organic compound, a second organic compound, and a third organic compound; the first organic compound has a function of converting triplet excitation energy into luminescence, the second organic compound has a benzofuropyrimidine skeleton or a benzothienopyrimidine skeleton, the third organic compound has a function of converting singlet excitation energy into luminescence, a light-emitting element, wherein the light emitted by the light-emitting layer includes light emitted by the third organic compound;

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