Light emission element, display device, electronic apparatus, and lighting device

Abstract

To provide a light emission element having high light emission efficiency in a light emission element including a material emitting fluorescent light as a light emission material.SOLUTION: A light emission element includes a pair of electrodes and an EL layer sandwiched between the pair of electrodes. Light emission exhibited by the EL layer has a ratio of delay fluorescent component due to triplet-triplet annihilation being 20% or more, and has a light emission spectrum peak in a blue wavelength band. The EL layer includes an organic compound with an energy difference of 0.5 eV or more between a minimum excitation singlet energy level and a minimum excitation triplet energy level. Further the EL layer includes a benzo (a) anthracene compound.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] One aspect of the present invention relates to a benz[a]anthracene compound. a light-emitting element having a light-emitting layer sandwiched between a pair of electrodes, the light-emitting element being The present invention relates to a display device, an electronic device, and a lighting device having the above.

[0002] Note that one embodiment of the present invention is not limited to the above technical fields. The technical field of one aspect of the present invention relates to an article, a method, or a manufacturing method. One aspect of the invention is a process, machine, manufacture, or composition of matter. Therefore, the present invention disclosed in this specification more specifically relates to the In one embodiment, the present invention relates to a semiconductor device, a display device, a liquid crystal display device, a light-emitting device, a lighting device, and the like. As examples, a device, a power storage device, a storage device, a driving method thereof, or a manufacturing method thereof These can be listed as follows. [Background technology]

[0003] In recent years, electroluminescence (EL) The basic structure of these light-emitting devices is as follows: The device has a pair of electrodes and a layer containing a light-emitting material (EL layer) sandwiched between them. By applying a voltage across the material, light is emitted from the luminescent material.

[0004] Since the above-mentioned light-emitting element is a self-luminous type, a display device using it has excellent visibility and It has the advantage of not requiring a light source and consuming little power. It also has the advantage of high response speed.

[0005] An organic material is used as the light-emitting material, and an EL layer containing the light-emitting organic material is formed between a pair of electrodes. In the case of a light-emitting element (for example, an organic EL element) provided with a As a result, electrons are injected from the cathode and holes are injected from the anode into the light-emitting EL layer, A current flows, and the injected electrons and holes recombine to form a light-emitting organic compound. The material is excited, and light can be emitted from the excited light-emitting organic material.

[0006] The types of excited states that organic materials can form include singlet excited states (S * ) and triplet excited states state(T * ) emission from the singlet excited state is fluorescence, and emission from the triplet excited state is phosphorescence. The statistical generation ratio of these in a light-emitting element is called S * :T * =1 Therefore, it is more preferable to use a light-emitting element that uses a phosphorescent material than a light-emitting element that uses a fluorescent material. Therefore, a light-emitting element in which the triplet excited state is used can obtain a higher luminous efficiency. In recent years, there has been active development of light-emitting devices using phosphorescent materials that can convert the state of matter into light. There are.

[0007] Among light-emitting elements using phosphorescent materials, light-emitting elements that emit blue light have high Due to the difficulty in developing stable materials with triplet excited energy levels, they have not yet been put to practical use. Therefore, in light-emitting elements that emit blue light, more stable fluorescent materials are used. Light-emitting devices using fluorescent materials are being developed, and methods for improving the luminous efficiency of light-emitting devices using fluorescent materials are being developed. The law is being explored.

[0008] The triplet-triplet luminescence mechanism is one that can convert part of the triplet excited state into luminescence. Triplet-triplet annihilation (TTA) is known TTA is a type of triplet exciton that is generated by two triplet excitons coming close to each other. The exchange of spin angular momentum and the singlet exciton is said to be generated.

[0009] Anthracene compounds are known to produce TTA. By using an anthracene compound as a host material of a light-emitting element, blue light is emitted. It has been reported that the device exhibits an external quantum efficiency of more than 10%. The proportion of delayed fluorescence components due to TTA of anthracene compounds among the emission components of the molecules is It has been reported that the rate is about 10%.

[0010] Furthermore, tetracene compounds are known to have a high proportion of delayed fluorescence components due to TTA. In Non-Patent Document 2, the delayed emission from tetracene compounds due to TTA is The proportion of fluorescent components is reported to be higher than that of anthracene compounds. [Prior art documents] [Non-patent literature]

[0011] [Non-Patent Document 1] Tsunenori Suzuki and six others, Japanese Journal of Applied Physics, vol. 53, 052102 (2014) [Non-patent document 2] DYKondakov and 3 others, Journal of Applied Physics, vol.106, 124510 (2009) Summary of the Invention [Problem to be solved by the invention]

[0012] In order to increase the luminous efficiency of a light-emitting element having a fluorescent material, it is necessary to remove three converting the energy of the doublet excitons into the energy of luminescent singlet excitons; and It is important to increase the conversion efficiency. It is important to convert the energy from the photon into the energy of singlet excitons. It is particularly important to increase the proportion of delayed fluorescence components based on TTA among the luminescent components exhibited by the device. This is important because a high proportion of delayed fluorescence components based on TTA means that the emission This is because it means that the rate of generation of singlet excitons increases.

[0013] Tetracene compounds, which are known to have a high proportion of delayed fluorescence due to TTA, are Compounds with lower excitation energy than thracene compounds and exhibiting yellow or longer wavelength emission Therefore, the tetracene compound can be used as a host material for a light-emitting element that emits blue light. Therefore, it is difficult to use the blue light emitting element with high luminous efficiency. To increase the fluorescence intensity, the proportion of delayed fluorescence components due to TTA is high and the excitation energy is high. A compound is needed.

[0014] Therefore, in one embodiment of the present invention, a light-emitting element including a fluorescent material has high emission efficiency. Another object of the present invention is to provide a light-emitting element that emits blue light. It is an object of the present invention to provide a light-emitting element having high luminous efficiency. In one embodiment of the present invention, a compound having a high proportion of delayed fluorescent components due to TTA among luminescent components is used. Alternatively, in one embodiment of the present invention, TTA is a light-emitting component. Another object of the present invention is to provide a light-emitting element having a high proportion of delayed fluorescent components due to the present invention. An object of one embodiment of the present invention is to provide a novel compound. In this embodiment, an object is to provide a light-emitting element having a novel compound. One embodiment of the present invention provides a novel light-emitting device with high luminous efficiency and reduced power consumption. Another object of one embodiment of the present invention is to provide a novel display device. This is one of the challenges.

[0015] The above description of the problem does not preclude the existence of other problems. The embodiment does not necessarily have to solve all of these problems. Problems other than those mentioned above can be solved by the specification. It is clear from the description of the specification, etc. that the problems other than those mentioned above cannot be extracted from the description of the specification, etc. It is possible to issue it. [Means for solving the problem]

[0016] One embodiment of the present invention is a light-emitting element that includes at least an EL layer and that effectively utilizes TTA in the EL layer. By efficiently generating triplet excitons, triplet excitons that do not contribute to light emission are converted into singlet excitons, Emission from singlet excitons or via energy transfer to guest materials (fluorescent dopants) The present invention is characterized in that the luminous efficiency of the light-emitting element is improved by causing the light-emitting element (e.g., the luminous element) to emit light.

[0017] In order to efficiently generate TTA in the EL layer, it is necessary to use TTA as the luminescent component. It is important to use a compound in which the proportion of delayed fluorescent components due to the luminescence is high as the host material. In particular, in a light-emitting element that emits blue light, a compound having high excitation energy is used as a host. It is important to use it as a coating material.

[0018] Therefore, one embodiment of the present invention is a light-emitting device including a pair of electrodes and an EL layer sandwiched between the pair of electrodes. The light emitting device has an EL layer, and the light emitted from the EL layer is a delayed fluorescence component due to triplet-triplet annihilation. The proportion of the blue light component is 20% or more, and the blue light component has an emission spectrum peak in the blue wavelength band. The light-emitting element is characterized by:

[0019] Another embodiment of the present invention is a light-emitting diode (LED) having a pair of electrodes and an EL layer sandwiched between the pair of electrodes. The light emitted from the EL layer is a delayed fluorescent component due to triplet-triplet annihilation. The proportion of these wavelengths is 20% or more, and there is a small amount of light in the wavelength band between 400 nm and 550 nm. The light-emitting element is characterized by having at least one emission spectrum peak.

[0020] Another embodiment of the present invention is a light-emitting diode (LED) having a pair of electrodes and an EL layer sandwiched between the pair of electrodes. The EL layer has a lowest excited singlet energy level and a lowest excited triplet energy level. The organic compound has an energy difference of 0.5 eV or more between the energy level of the EL layer and the The emitted light is 20% or more in the delayed fluorescence component and is emitted in the blue wavelength band. The light-emitting element is characterized by having an optical spectrum peak.

[0021] Another embodiment of the present invention is a light-emitting diode (LED) having a pair of electrodes and an EL layer sandwiched between the pair of electrodes. The EL layer has a lowest excited singlet energy level and a lowest excited triplet energy level. The organic compound has an energy difference of 0.5 eV or more between the energy level of the EL layer and the The emission is such that the proportion of delayed fluorescence components is 20% or more, and the wavelength is 400 nm or more and 55 100 nm or less wavelength band, and It is a light-emitting element.

[0022] In each of the above-mentioned configurations, the peak wavelength of the fluorescent emission spectrum of the organic compound is The difference in energy equivalent between the peak wavelength of the phosphorescence emission spectrum and is 0.5 eV or more. preferable.

[0023] Another embodiment of the present invention is a light-emitting diode (LED) having a pair of electrodes and an EL layer sandwiched between the pair of electrodes. The EL layer contains a compound having a benzo[a]anthracene skeleton. The EL layer is characterized in that the proportion of delayed fluorescent components in the light emitted by the EL layer is 20% or more. It is a light-emitting element.

[0024] In each of the above structures, the EL layer preferably contains a guest material that exhibits fluorescence.

[0025] In the above structure, the guest material preferably has a pyrene skeleton.

[0026] Another embodiment of the present invention is a benzo[a]anthracene compound represented by general formula (G1): It is a mixture.

[0027] [ka]

[0028] In general formula (G1), A represents a substituted or unsubstituted carbazolyl group, R 1 ~ R 10 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted alkyl group having 6 to 13 carbon atoms; represents R11 is hydrogen, an alkyl group having 1 to 6 carbon atoms, or a cycloalkyl group having 3 to 6 carbon atoms. Ar represents a group having 6 to 1 carbon atoms, or a substituted or unsubstituted phenyl group; 3, the arylene group may have a substituent, and the substituents are bonded to each other. They may also combine to form a ring.

[0029] Another aspect of the present invention is a benzo[a]anthracene compound represented by general formula (G2): It is a mixture.

[0030] [ka]

[0031] In general formula (G2), R 1 ~R 10 , and R 21 ~R 28 are each independently , hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a carbon R represents a substituted or unsubstituted aryl group having a number of 6 to 13; 11 is hydrogen, carbon an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted alkyl group; Ar represents an arylene group having 6 to 13 carbon atoms; The arylene group may have substituents, and the substituents may be bonded to each other to form a ring. .

[0032] Another embodiment of the present invention is a benzo[a]anthracene compound represented by general formula (G3): It is a mixture.

[0033] [ka]

[0034] In general formula (G3), R 1 ~R 10 , and R 31 ~R 35 are each independently , hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a carbon R represents a substituted or unsubstituted aryl group having a number of 6 to 13; 11 is hydrogen, carbon an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted alkyl group; Ar represents an arylene group having 6 to 13 carbon atoms; The arylene group may have substituents, and the substituents may be bonded to each other to form a ring. .

[0035] In addition, Ar in each of the above structures may be a substituted or unsubstituted phenylene group, a substituted or unsubstituted The benz[a]anthracene compound is preferably a benzo[a]anthracene compound having either a substituted biphenyldiyl group or a substituted biphenyldiyl group. It's nice.

[0036] In addition, Ar in each of the above structures may be a substituted or unsubstituted phenylene group, such as benzo[a ]Anthracene compounds are preferred.

[0037] In addition, Ar in each of the above structures may be a benzoyl group which is a substituted or unsubstituted m-phenylene group. [a] An anthracene compound is preferred.

[0038] Another embodiment of the present invention is a benzo[a]anthracene compound represented by general formula (G4): It is a mixture.

[0039] [ka]

[0040] In general formula (G4), R1 ~R 10 , R 21 ~R 28 , and R 41 ~R 44 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; R 11 is hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or or a substituted or unsubstituted phenyl group.

[0041] Another aspect of the present invention is a benzo[a]anthracene compound represented by general formula (G5): It is a mixture.

[0042] [ka]

[0043] In general formula (G5), R 1 ~R 10 , R 31 ~R 35 , and R 41 ~R 44 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; R 11 is hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or or a substituted or unsubstituted phenyl group.

[0044] Another embodiment of the present invention is a compound represented by the structural formula (100): It is a compound.

[0045] [ka]

[0046] Another embodiment of the present invention is a light-emitting diode (LED) having a pair of electrodes and an EL layer sandwiched between the pair of electrodes. The EL layer contains the benz[a]anthracene compound described in each of the above configurations. It is a light-emitting element with the characteristic

[0047] Another embodiment of the present invention is a light-emitting diode (LED) having a pair of electrodes and an EL layer sandwiched between the pair of electrodes. The EL layer is a light-emitting device comprising the benz[a]anthracene compound according to any one of the above configurations. and the proportion of delayed fluorescent components in the light emitted by the EL layer is 20% or more. The light-emitting device is characterized by the following characteristics.

[0048] In each of the above structures, the EL layer preferably contains a guest material that exhibits fluorescence. .

[0049] In the above configuration, the guest material exhibits an emission spectrum peak in the blue wavelength band. It is preferable that the function be such that

[0050] In each of the above structures, the guest material preferably exhibits delayed fluorescence.

[0051] In each of the above structures, the guest material preferably has a pyrene skeleton.

[0052] Another embodiment of the present invention is a light-emitting element having any of the above structures, a color filter, a seal, or a light-emitting device. Another embodiment of the present invention is a display device including the display device. The present invention also provides an electronic device having a touch sensor and a housing. The present invention is a lighting device having a light-emitting element having any of the above configurations and a housing or a touch sensor. Furthermore, one embodiment of the present invention is not only a light-emitting device having a light-emitting element, but also an electronic device having a light-emitting device. Therefore, the light-emitting device in this specification includes an image display device. It also refers to a light source (including lighting equipment) with a connector, such as F PC (Flexible Printed Circuit), TCP (Tape Ca Module with a Threaded Package attached, printed wiring at the end of the TCP Module with a plate or COG (Chip On Glass) type light emitting element A module in which an IC (integrated circuit) is directly mounted may also include a light-emitting device. [Effects of the Invention]

[0053] According to one embodiment of the present invention, a light-emitting element having a fluorescent material and high emission efficiency can be obtained. Alternatively, according to one embodiment of the present invention, a light-emitting element that emits blue light can be provided. Therefore, a light-emitting element with high emission efficiency can be provided. It is possible to provide a compound in which the proportion of delayed fluorescence components due to TTA is high among the luminescent components. Alternatively, according to one embodiment of the present invention, the proportion of delayed fluorescence components due to TTA among luminescent components is high. According to one embodiment of the present invention, a novel compound can be provided. Alternatively, one embodiment of the present invention provides a light-emitting element including a novel compound. According to one embodiment of the present invention, the light-emitting device can have high light-emitting efficiency and low power consumption. Alternatively, according to one embodiment of the present invention, a novel light-emitting device can be provided. It is possible to provide a display device.

[0054] The description of these effects does not preclude the existence of other effects. An embodiment does not necessarily have to have all of these effects. The above will be made clear from the description, drawings, claims, etc. It is possible to extract other effects from the descriptions in the aspects and claims. [Brief explanation of the drawings]

[0055] [Figure 1] 1A and 1B are a schematic cross-sectional view of a light-emitting element of one embodiment of the present invention and a schematic diagram illustrating the correlation between energy levels. [Figure 2] FIG. 1 illustrates a calculation example of a compound according to one embodiment of the present invention. [Figure 3] 1A and 1B are schematic cross-sectional views of a light-emitting element according to one embodiment of the present invention. [Figure 4] 1A and 1B are schematic cross-sectional views of a light-emitting element according to one embodiment of the present invention. [Figure 5] 1A and 1B are schematic cross-sectional views of a light-emitting element according to one embodiment of the present invention. [Figure 6] 1A and 1B are a schematic cross-sectional view of a light-emitting element of one embodiment of the present invention and a schematic diagram illustrating the correlation between energy levels. [Figure 7] 1A and 1B are a schematic cross-sectional view of a light-emitting element of one embodiment of the present invention and a schematic diagram illustrating the correlation between energy levels. [Figure 8] FIG. 1 is a schematic cross-sectional view of a semiconductor element according to one embodiment of the present invention. [Figure 9] 1A and 1B are a block diagram and a circuit diagram illustrating a display device of one embodiment of the present invention. [Figure 10] FIG. 1 is a perspective view illustrating an example of a touch panel of one embodiment of the present invention. [Figure 11] 1A and 1B are cross-sectional views illustrating examples of a display device and a touch sensor according to one embodiment of the present invention. [Figure 12] FIG. 1 is a cross-sectional view illustrating an example of a touch panel of one embodiment of the present invention. [Figure 13] 1A and 1B are a block diagram and a timing chart of a touch sensor according to one embodiment of the present invention. [Figure 14] FIG. 1 is a circuit diagram of a touch sensor according to one embodiment of the present invention. [Figure 15]FIG. 1 is a perspective view illustrating a display module of one embodiment of the present invention. [Figure 16] 1A to 1C illustrate electronic devices of one embodiment of the present invention. [Figure 17] 1A to 1C illustrate a lighting device according to one embodiment of the present invention. [Figure 18] FIG. 1 is a diagram illustrating an NMR chart of a compound according to an example. [Figure 19] 1A and 1B are diagrams illustrating absorption spectra and emission spectra of compounds according to an example. [Figure 20] 1A and 1B are diagrams illustrating absorption spectra and emission spectra of compounds according to an example. [Figure 21] 10A and 10B are diagrams illustrating fluorescence lifetime characteristics of light-emitting elements according to the examples. [Figure 22] FIG. 10 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 23] FIG. 10 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 24] FIG. 10 is a graph showing luminance-voltage characteristics of a light-emitting element according to an example. DETAILED DESCRIPTION OF THE INVENTION

[0056] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the above description, and the embodiments and details thereof may be modified without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the embodiments described below. It is not to be construed as being limited to the content.

[0057] In addition, the position, size, range, etc. of each component shown in the drawings etc. are not necessarily shown in order to facilitate understanding. It may not represent the actual position, size, range, etc. Therefore, the disclosed invention The position, size, range, etc. are not necessarily limited to those disclosed in the drawings, etc.

[0058] In addition, in this specification, ordinal numbers such as 1st, 2nd, etc. are used for convenience. Therefore, for example, "first" may be changed to "second" "the" or "third" can be used as appropriate for explanation. The ordinal numbers listed in the specification do not match the ordinal numbers used to identify an aspect of the present invention. There are cases where this happens.

[0059] In addition, in this specification and the like, when explaining the configuration of the invention using drawings, the same The reference numerals may be commonly used even among different drawings.

[0060] In addition, in this specification and the like, the terms "film" and "layer" are interchangeable. For example, the term "conductive layer" can be changed to the term "conductive film." Alternatively, for example, the term "insulating film" may be changed to "insulating layer" It may be possible to change the term to

[0061] In this specification and the like, the singlet excited state (S * ) is a single atom with excitation energy The singlet excited state is the one with the lowest energy. The singlet excited energy level is the lowest excited singlet state. The lowest excited energy level among the singlet excited energy levels is The lowest excited singlet energy level (S1) is referred to as the lowest excited singlet energy level. Even when written as singlet excited states and singlet excited energy levels, the lowest excited state It may refer to the singlet state and the S1 level.

[0062] In this specification and the like, the triplet excited state (T * ) is a triplet with excitation energy The triplet excited state is the excited state with the lowest energy. The lowest excited triplet state is called the triplet excited energy level. The lowest triplet excited energy level is the The lowest excited triplet energy level (T1) is referred to as the lowest excited triplet energy level. Even when written as triplet excited states and triplet excited energy levels, the lowest excited triplet It may refer to the singlet state and the T1 level.

[0063] In this specification and the like, the fluorescent material is a material that emits light when it relaxes from a singlet excited state to a ground state. A phosphorescent material is a material that emits light in the visible light region. When combined with a phosphorescent material, it emits light in the visible light region at room temperature. is one of the materials that can convert triplet excitation energy into visible light.

[0064] In this specification, room temperature refers to any temperature between 0°C and 40°C.

[0065] In this specification, the blue wavelength band is a wavelength band of 400 nm or more and 550 nm or less. It is a long band, and blue emission means that the blue emission has at least one emission spectrum peak in that band. It is a light emission.

[0066] (Embodiment 1) In this embodiment, a light-emitting element of one embodiment of the present invention will be described below with reference to FIGS. 1 and 2. Reveal.

[0067] <Configuration example of light-emitting element> First, the structure of a light-emitting element of one embodiment of the present invention will be described with reference to FIGS. The following explains this.

[0068] FIG. 1A is a schematic cross-sectional view of a light-emitting element 150 of one embodiment of the present invention.

[0069] The light-emitting element 150 includes an EL layer 1 provided between a pair of electrodes (electrode 101 and electrode 102). 00. The EL layer 100 has at least a light-emitting layer 130. In the description, the electrode 101 of the pair of electrodes is the anode and the electrode 102 is the cathode. However, the configuration of the light emitting element 150 may be reversed.

[0070] The EL layer 100 shown in FIG. 1A has a functional layer in addition to the light-emitting layer 130. The layers are a hole injection layer 111, a hole transport layer 112, an electron transport layer 118, and an electron injection layer 119. The configuration of the EL layer 100 is not limited to the configuration shown in FIG. layer 111, a hole transport layer 112, an electron transport layer 118, and an electron injection layer 119. Alternatively, the EL layer 100 may have a structure including at least one of holes or electrons. the injection barrier of the hole or electron is reduced, the transportability of the hole or electron is improved, and the transportability of the hole or electron is improved. A functional layer having a function of inhibiting or suppressing the quenching phenomenon caused by an electrode. The configuration may also include the following.

[0071] FIG. 1(B) is a cross-sectional view showing an example of the light-emitting layer 130 shown in FIG. 1(A). The light-emitting layer 130 shown in FIG. 1B includes at least a host material 131 and a guest material 132. , has.

[0072] The host material 131 converts triplet excitation energy to singlet excitation energy by TTA. By doing so, triplet excitation light generated in the light-emitting layer 130 can be converted into A portion of the energy is converted to singlet excitation energy by TTA in the host material 131. The singlet excitation energy generated by TTA can be converted to guest material 132. By moving the light, it becomes possible to extract the light as fluorescent light. The lowest excited singlet energy (S1) level of 131 is higher than the S1 level of the guest material 132. In addition, it is preferable that the lowest excited triplet excitation energy (T1) of the host material 131 is The level is preferably lower than the T1 level of the guest material 132.

[0073] The host material 131 may be composed of a single compound or a plurality of compounds. The guest material 132 may be a light-emitting organic material. The light-emitting organic material may be a material capable of emitting fluorescence (hereinafter also referred to as a fluorescent material). In the following description, the guest material 132 is preferably a fluorescent material. The guest material 132 may be replaced with a fluorescent material. good.

[0074] <Light-emitting mechanism of light-emitting elements> First, the light emitting mechanism of the light emitting element 150 will be described below.

[0075] In the light-emitting element 150 of one embodiment of the present invention, a pair of electrodes (electrode 101 and electrode 102) By applying a voltage between the cathode and the anode, electrons flow from the cathode and holes flow from the anode. The electrons and holes are then injected into the EL layer 100, causing a current to flow. Among the excitons generated by carrier recombination, The ratio of singlet excitons to triplet excitons is 1:3 due to statistical probability. The probability of generating doublet excitons is 25%.

[0076] An exciton is a pair of carriers (electrons and holes). Since the material has an exciton, the material in which the exciton is formed is in an excited state.

[0077] Furthermore, singlet excitons are generated in the EL layer 100 through the following two processes, and guest Light emission from material 132 is obtained. (α) Direct generation process (β)TTA process

[0078] ≪(α) Direct generation process≫ First, carriers (electrons or holes) recombine in the light-emitting layer 130 of the EL layer 100. The case where singlet excitons are formed by combining the two electrons is described below.

[0079] When carriers recombine in the host material 131, excitons are generated, which An excited state (singlet excited state or triplet excited state) of the material 131 is formed. When the excited state of the host material 131 is a singlet excited state, the S1 level of the host material 131 The singlet excitation energy is transferred from the guest material 132 to the S1 level of the guest material 132. The singlet excited state of the host material 132 is formed. When the first excited state is reached, this will be explained in the (β)TTA process described later.

[0080] Also, when carriers recombine in the guest material 132, they undergo exciton generation. An excited state (singlet excited state or triplet excited state) of the guest material 132 is formed.

[0081] When the excited state of the formed guest material 132 is a singlet excited state, the guest material 13 Light emission is obtained from the singlet excited state of 2. In this case, in order to obtain high luminescence efficiency, Preferably, the fluorescent quantum yield of the fluorescent material 132 is high.

[0082] On the other hand, when the triplet excited state of the guest material 132 is formed, the guest material 132 emits fluorescence. Since the guest material 132 is a material, the triplet excited state of the guest material 132 is thermally deactivated and does not contribute to light emission. However, when the T1 level of the host material 131 is lower than the T1 level of the guest material 132, The triplet excitation energy of the guest material 132 is calculated from the T1 level of the guest material 132 to the host In this case, the energy can be transferred to the T1 level of the ion-doped material 131. β) The TTA process allows the conversion of triplet excitation energy to singlet excitation energy. It becomes Noh.

[0083] In addition, when the T1 level of the host material 131 is higher than the T1 level of the guest material 132, In this case, the weight ratio of the host material 131 to the guest material 132 is By lowering the weight ratio, the probability of carrier recombination in the guest material 132 can be reduced. In addition, the T1 level of the host material 131 can be increased to the T1 level of the guest material 132. Specifically, the host material 131 can reduce the probability of energy transfer. The weight ratio of the guest material 132 to 1 is preferably greater than 0 and equal to or less than 0.05.

[0084] ≪(β)TTA process≫ Next, triplet excitons formed in the recombination process of carriers in the light-emitting layer 130 Therefore, the case where singlet excitons are formed will be described.

[0085] Here, when the T1 level of the host material 131 is lower than the T1 level of the guest material 132, A schematic diagram showing the correlation of the energy levels at this time is shown in Figure 1(C). The notations and symbols in FIG. 1C are as follows: The T1 level of the guest material 132 may be higher than the T1 level of the guest material 132. Host (131): Host material 131 Guest (132): Guest material 132 (fluorescent material) ·S FH : S1 level of the host material 131 T FH : T1 level of the host material 131 ·S FG : S1 level of guest material 132 (fluorescent material) T FG : T1 level of guest material 132 (fluorescent material)

[0086] Carriers recombine in the host material 131, and excitons are generated in the host material 13 The excited state of 1 is formed. At this time, if the generated exciton is a triplet exciton, When two triplet excitons approach each other, one of them enters the S1 Level (S FH ) into a singlet exciton with an energy of (See Figure 1(C) TTA). This is represented by the following general formula (G11) or (G12): can be.

[0087] 3 H+ 3 H → 1 H * + 1 H (G11) 3 H+ 3 H → 3 H* + 1 H (G12)

[0088] General formula (G11) represents a compound in which two triplet excitons ( 3 H)'s Spi Two triplet excitons ( 3 H) to singlet excitons ( 1 H * ) is born In addition, general formula (G12) represents a reaction in which two triple bonds are formed in the host material 131. term excitons ( 3 H) with two triplet excitons ( 3 H) to electronically or vibrationally excited triplet excitons ( 3 H * ) is produced by the reaction In general formulas (G11) and (G12), 1 H is the singlet basis in the host material 131 Represents the state.

[0089] The general formula (G11) and the general formula (G12) occur with the same probability, but the sum of the spin quantum numbers A triplet exciton pair with a spin quantum number of 1 (atomic unit) has three times the spin quantum number of a pair with a spin quantum number of 0. In other words, among the excitons generated from two triplet excitons, the newly generated The ratio of singlet excitons to triplet excitons generated is 1:3 due to statistical probability. If the density of triplet excitons in the optical layer 130 is sufficiently high (e.g., 1×10 -12 cm -3 In the above, the deactivation of a single triplet exciton is ignored, and the deactivation of two adjacent triplet excitons is considered. You can only think about the reaction.

[0090] Therefore, one reaction of general formula (G11) and three reactions of general formula (G12) As shown in general formula (G13), eight triplet excitons ( 3 H) produces one singlet exciton ( 1 H * ) and three electronically or vibrationally excited triplet excitons ( 3 H * ) generates This will happen.

[0091] 8 3 H → 1 H * +3 3 H * +4 1 H (G13)

[0092] The electronically or vibrationally excited triplet excitons ( 3 H * ) is released by relaxation into triplet excitons ( 3 H), and then again with other triplet excitons of the general formula ( G13) reaction is repeated. Therefore, in general formula (G13), triplet excitons ( 3 H ) are all singlet excitons ( 1 H * ), five triplet excitons ( 3 H) from one singlet exciton ( 1 H * ) is produced (general formula (G14)).

[0093] 5 3 H → 1 H * +4 1 H (G14)

[0094] On the other hand, singlet excitons ( 1 H * ) and triplet excitons ( 3 H) statistical generation rate is 1 H * : 3H=1:3. In other words, singlet excitons are directly generated by the recombination of carriers injected from a pair of electrodes. The probability of this happening is 25%.

[0095] Therefore, the singlet excitations generated directly by the recombination of carriers injected from a pair of electrodes The excitons injected from the pair of electrodes are combined with the singlet excitons generated by TTA. 20 excitons (singlet and triplet excitons) generated directly by the recombination of trapped carriers. From the total number of singlet excitons, eight singlet excitons can be generated (general formula (G15)). By using TTA, the probability of singlet exciton generation has increased from the conventional 25% to a maximum of 40% (= 8 / It is possible to improve it up to 20.

[0096] 5 1 H * +15 3 H → 5 1 H * +(3 1 H * +12 1 H) (G15)

[0097] The singlet excitons of the host material 131 formed by the singlet excitons generated by the above process In the excited state, the S1 level (S FH ) to lower energy The S1 level (S FG ) energy transfer occurs (Figure 1(C) Route A). Then, the guest material 132 in the singlet excited state It emits fluorescence.

[0098] In addition, carriers recombine in the guest material 132, and the resulting excitons form When the excited state is a triplet excited state, the T1 level (T FH ) is When the T1 level (T FG ) of the host material is lower than that of the guest material, the triplet excitation energy of T FG is transferred to T without deactivation and is utilized for TTA (see Route B in Fig. 1(C)). FH

[0099] Also, when the T1 level (T FG ) of the guest material 132 is lower than the T1 level (T FH ) of the host material 131, the weight ratio of the host material 131 to the guest material 132 is preferably lower for the guest material 132. Specifically, the weight ratio of the guest material 132 to the host material 131 is preferably greater than 0 and not more than 0.05. By doing so, the probability of carrier recombination in the guest material 132 can be reduced. Also, the probability of energy transfer from the T1 level (T ) of the host material 131 to the T1 level (T ) of the guest material 132 can be reduced. FH ) to the T1 level (T FG ) of the guest material 132 can be reduced.

[0100] As described above, by TTA, the triplet excitons formed in the light-emitting layer 130 are converted into singlet excitons, so that light emission from the guest material 132 can be efficiently obtained.

[0101] <Regarding TTA efficiency> As described above, TTA can improve the generation probability of singlet excitons and the light emission efficiency of the light-emitting device. However, in order to obtain a high light emission efficiency, it is important to increase the probability of TTA occurring (also referred to as TTA efficiency). That is, it is important that the ratio of the delayed fluorescence component due to TTA in the light emitted by the light-emitting device is high.

[0102] As explained above, the TTA process can improve the generation probability of singlet excitons. It is possible to generate 25% of the electrons by direct recombination of the carriers injected from the pair of electrodes. In combination with the singlet excitons from the ZnSe, the singlet exciton generation probability can be increased by up to 40%. That is, the delayed fluorescence component due to TTA accounts for a large proportion of the light emitted by the light-emitting element. The percentage can be improved to (40%-25%) / 40%=37.5%.

[0103] Anthracene is commonly used as a host material in light-emitting devices that emit blue light. In the case of the thracene compound, the delayed fluorescence component due to TTA accounts for about 10% of the light emitted. On the other hand, tetracene compounds, which are known to have higher TTA efficiency, are yellowish or Since tetracene compounds emit light at wavelengths longer than yellow, we have selected tetracene compounds that emit blue light. It is difficult to use such a compound as a host material for a light-emitting device.

[0104] Therefore, in a light-emitting device that emits blue light, the delayed fluorescence component due to TTA is dominant. In order to increase the proportion of tetracene and obtain high luminous efficiency, delayed fluorescence due to TTA is required. It has a high proportion of light components and, like anthracene, has high excitation energy. It is necessary to use a compound having the above structure as a host material.

[0105] <Quantum chemical calculation> Therefore, anthracene, a three-ring aromatic hydrocarbon, and tetrahydrofuran, a four-ring aromatic hydrocarbon, For helical and benz[a]anthracene, the excitation energies were calculated using quantum chemical calculations. -levels (S1 and T1 levels), and the transition from the singlet ground state to the lowest excited singlet state. The dipole moment and oscillator strength were calculated. The compounds for which the calculations were performed are shown in Figure 2, and the calculation results are shown in Figure 3. The results are shown in Table 1. Figure 2(A) shows anthracene, Figure 2(B) shows tetracene, and Figure 2(C) shows Benz[a]anthracene. The calculation method is as follows:

[0106] [Table 1]

[0107] Calculate the S1 level, T1 level, transition dipole moment, and oscillator strength of the above compound. Therefore, the most stable structure of each compound in the singlet ground state was determined using density functional theory (DFT). The quantum chemistry calculation program used was Gaussian09. This was performed using a high-performance computer (SGI, ICE X). The function used was 6-311G(d,p), and the functional used was B3LYP. Using time-dependent density functional theory (TD-DFT), the S1 level, T1 level, and singlet basis set are calculated. The transition dipole moment from the lowest excited singlet state to the lowest excited singlet state was calculated. The energy is divided into potential energy, electrostatic energy between electrons, and kinetic energy of electrons. It is expressed as the sum of exchange-correlation energies that include all the complex interactions between electrons. The exchange-correlation interaction is a functional (meaning a function of a function) of the one-electron potential expressed in terms of the electron density. The calculation is highly accurate because it approximates

[0108] As shown in Table 1, benzo[a]anthracene is a four-ring aromatic hydrocarbon. It has high S1 and T1 levels similar to those of anthracene, a three-ring aromatic hydrocarbon. It can be seen that...

[0109] The transition dipole moment of benz[a]anthracene is The oscillator strength is also sufficiently large. The dipole moment and oscillator strength are calculated from the singlet ground state to the lowest excited singlet state of each compound. The transition dipole moment and oscillator strength are related to the transition to The orientations of the points (x, y, and z) correspond to the directions indicated by the arrows in Figures 2(A), (B), and (C). The z direction is perpendicular to the paper. The transition dipole moment is negative because the direction of the transition dipole moment is x as shown in Figure 2. The magnitude of the transition dipole moment is its absolute value Therefore, the transition dipole moment of benz[a]anthracene is sufficiently It can be seen that it is large.

[0110] The transition dipole moment and oscillator strength from the singlet ground state to the lowest excited singlet state are large. This means that the lowest excited singlet state is easily generated. Anthracene, tetracene, and benz[a]anthracene produce the lowest excited singlet state. Therefore, it can be said that this compound is likely to exhibit high TTA efficiency in the TTA process.

[0111] Among them, tetracene is a four-ring aromatic hydrocarbon compound, but anthracene is A nonlinear four-ring aromatic carbon with a high singlet excitation energy comparable to that of Hydrogen compounds (e.g., benz[a]anthracene) have high excitation energies and Since this compound is likely to exhibit high TTA efficiency, the proportion of delayed fluorescence components due to TTA is This can improve the efficiency.

[0112] In order to obtain higher luminous efficiency than light-emitting elements having an anthracene compound as a host material, From a light-emitting device having an anthracene compound as a host material, the delayed fluorescence component due to TTA Specifically, it is preferable that the proportion of TTA in the light-emitting components emitted by the light-emitting element is high. It is preferable that the proportion of delayed fluorescence components due to is 20% or more.

[0113] Furthermore, the emission spectrum exhibited by the light-emitting element has an emission spectrum peak in the blue wavelength band. Specifically, it is preferable that the wavelength band is 400 nm or more and 550 nm or less. It is preferable that the emission spectrum has one peak.

[0114] In addition to TTA, the delayed fluorescence is generated by the light-emitting element. In addition, the thermal activation delay occurs due to the reverse intersystem crossing from the triplet excited state to the singlet excited state. For reverse intersystem crossing to occur efficiently, the energy between the S1 and T1 levels must be In other words, the energy difference between the S1 level and the T1 level is preferably 0.2 eV or less. If the energy difference is greater than 0.2 eV, reverse intersystem crossing is unlikely to occur. For A to be produced efficiently, the lowest excited singlet energy in the compound in which TTA occurs must be The energy difference between the lowest excited triplet energy level and the lowest excited triplet energy level is greater than 0.2 eV. It is preferable that the electron transport energy is 0.5 eV or more, and more preferable that the electron transport energy is 0.5 eV or more.

[0115] The lowest excited singlet energy level is the energy level at which an organic compound rises from the singlet ground state to the lowest excited singlet state. It can be observed from the absorption spectrum when the transition to the doublet state occurs. The lowest excited singlet energy level may be estimated from the peak wavelength of the fluorescence emission spectrum of the substance. The lowest excited triplet energy level is the energy level at which an organic compound rises from the singlet ground state to the lowest excited state. It can be observed from the absorption spectrum when the transition to the triplet state occurs, but the transition is forbidden. In such cases, it may be difficult to observe the phosphorescence of organic compounds. The lowest excited triplet energy level can be estimated from the spectral peak wavelength. In organic compounds, the peak wavelength of the fluorescence emission spectrum and the peak wavelength of the phosphorescence emission spectrum are The difference in energy equivalent between the peak wavelength and the It is more preferable that:

[0116] <Material> Next, components of a light-emitting element according to one embodiment of the present invention will be described in detail below.

[0117] <Light-emitting layer> In the light-emitting layer 130, the host material 131 is at least more abundant than the guest material 132 by weight. The guest material 132 (fluorescent material) is dispersed in the host material 131. In the example 130, the host material 131 can be a material that emits light. In particular, organic compounds with a high proportion of delayed fluorescence components due to triplet-triplet annihilation (TTA) are preferred. Specifically, an organic compound in which the proportion of delayed fluorescence components due to TTA is 20% or more is preferable. Among them, compounds having a benzo[a]anthracene skeleton are particularly preferred. In the light-emitting layer 130, the host material 131 is composed of one kind of compound. It may be composed of a single compound or a plurality of compounds.

[0118] In the light-emitting layer 130, the guest material 132 is not particularly limited, but may be an anthracene. Helical derivatives, tetracene derivatives, chrysene derivatives, phenanthrene derivatives, pyrene derivatives compounds, perylene derivatives, stilbene derivatives, acridone derivatives, coumarin derivatives, phenoxy Preferred are thiazin derivatives, phenothiazine derivatives, etc., and for example, the following materials can be used: can.

[0119] 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine Lysine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthracene) (aryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), ,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluorene-9-yl] N,N'-phenyl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn) Bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluorene -9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPr n), N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'- Diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carba 4'-(10-phenyl-9-anthryl)triphenylamine ( Abbreviation: YGAPA), 4-(9H-carbazol-9-yl)-4'-(9,10-difluoromethyl) (phenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl Phenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazo 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: PCB APA), N,N''-(2-tert-butylanthracene-9,10-diyldi-4 ,1-phenylene)bis[N,N',N'-triphenyl-1,4-phenylenediamine ] (abbreviation: DPABPA), N,9-diphenyl-N-[4-(9,10-diphenyl- 2-Anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: 2PCAPPA ), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N' -Triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N,N,N' ,N',N'',N'',N''',N'''-Octaphenyldibenzo[g,p]chloride Cen-2,7,10,15-tetraamine (abbreviation: DBC1), Coumarin 30, N-(9 ,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazole-3 -amine (abbreviation: 2PCAPA), N-[9,10-bis(1,1'-biphenyl-2- yl)-2-anthryl]-N,9-diphenyl-9H-carbazol-3-amine (abbreviation Name: 2PCABPhA), N-(9,10-diphenyl-2-anthryl)-N,N', N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9, 10-bis(1,1'-biphenyl-2-yl)-2-anthryl]-N,N',N'- Triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), 9,10-biphenyl Bis(1,1'-biphenyl-2-yl)-N-[4-(9H-carbazol-9-yl) Phenyl]-N-phenylanthracen-2-amine (abbreviation: 2YGABPhA), N, N,9-triphenylanthracen-9-amine (abbreviation: DPhAPhA), Coumarin 6 , Coumarin 545T, N,N'-Diphenylquinacridone (abbreviation: DPQd), Rubrene , 5,12-bis(1,1'-biphenyl-4-yl)-6,11-diphenyltetracene 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}propanediyl Tolyl (abbreviation: DCM2), N,N,N',N'-tetrakis(4-methylphenyl) ... 5,11-thracenediamine (abbreviation: p-mPhTD), 7,14-diphenyl-N, N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluora Benzene-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}p Propanedinitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1 ,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[i j]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinite (abbreviation: DCJTB), 2-(2,6-bis{2-[4-(dimethylamino)phenyl {4H-pyran-4-ylidene}propanedinitrile (abbreviated as BisDC M), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2, 3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl {4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJ™), 5,10,15,20-tetraphenylbisbenzo[5,6]indeno[1,2,3-c d:1',2',3'-lm]perylene, and the like.

[0120] In the light-emitting layer 130, materials other than the host material 131 and the guest material 132 are It may have.

[0121] The material that can be used for the light-emitting layer 130 is not particularly limited, but examples thereof include: Tris(8-quinolinolato)aluminum(III) (abbreviation: Alq), tris(4-methyl Almq3, bis(10- Hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq2), bis( 2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III)( Abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2 -(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), bis[ 2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ) and other gold Complex, 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3, 4-Oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl) (phenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1 ,2,4-triazole (abbreviation: TAZ), 2,2',2''-(1,3,5-benzene triyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), Sophenanthroline (abbreviated as BPhen), bathocuproine (abbreviated as BCP), 9-[ 4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-ca Heterocyclic compounds such as carbazole (abbreviation: CO11), 4,4'-bis[N-(1-naphthyl) N,N'-(phenyl)-N-phenylamino]biphenyl (abbreviation: NPB or α-NPD), Bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4, 4'-diamine (abbreviation: TPD), 4,4'-bis[N-(spiro-9,9'-bifluoromethyl) Aromatic alkyl groups such as [N-phenylamino]biphenyl (abbreviation: BSPB) In addition, anthracene derivatives, phenanthrene derivatives, pyrene derivatives, condensed polycyclic aromatic compounds such as chrysene derivatives, dibenzo[g,p]chrysene derivatives, etc. Specific examples include 9,10-diphenylanthracene (abbreviation: DPAnth), N ,N-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H- Carbazol-3-amine (abbreviation: CzA1PA), 4-(10-phenyl-9-anthracene) 4-(9H-carbazol-9-yl)triphenylamine (abbreviation: DPhPA), )-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA ), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]- 9H-Carbazol-3-amine (abbreviation: PCAPA), N,9-diphenyl-N-{4 -[4-(10-phenyl-9-anthryl)phenyl]phenyl}-9H-carbazol N,9-diphenyl-N-(9,10-diphenyl)-3-amine (abbreviation: PCAPBA), (2-anthryl)-9H-carbazol-3-amine (abbreviation: 2PCAPA), 6 ,12-Dimethoxy-5,11-diphenylchrysene, N,N,N',N',N'',N '',N''',N'''-Octaphenyldibenzo[g,p]chrysene-2,7,10 ,15-tetraamine (abbreviation: DBC1), 9-[4-(10-phenyl-9-anthracene phenyl]-9H-carbazole (abbreviation: CzPA), 3,6-diphenyl-9-[ 4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: DP CzPA), 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DP PA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 2-tert- Butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 9,9 '-Bianthryl (abbreviation: BANT), 9,9'-(stilbene-3,3'-diyl)di Phenanthrene (abbreviation: DPNS), 9,9'-(stilbene-4,4'-diyl)diphenyl Phenanthrene (abbreviation: DPNS2), 1,3,5-tri(1-pyrenyl)benzene (abbreviation: :TPB3) and the like. A plurality of compounds may be contained. In addition, the guest material may be selected from these compounds and known substances. A material with an energy gap larger than that of material 132 is called a Or, multiple types may be selected and used.

[0122] The light-emitting layer 130 may be composed of two or more layers. When the light-emitting layer 130 is formed by laminating the first light-emitting layer and the second light-emitting layer in this order from the hole transport layer side, a substance having hole transport properties is used as a host material for the first light-emitting layer, and a substance having hole transport properties is used as a host material for the second light-emitting layer In this case, at least It is preferable that another light-emitting layer contains a compound having a benz[a]anthracene skeleton. Desirable.

[0123] Next, other details of the configuration of the light emitting element 150 shown in FIG. 1(A) will be described below. .

[0124] <Pair of electrodes> The electrode 101 and the electrode 102 have the function of injecting holes and electrons into the light-emitting layer 130. The electrodes 101 and 102 are made of metals, alloys, conductive compounds, and mixtures or laminates thereof. The metal can be formed by using aluminum, and other materials. transition metals such as silver, tungsten, chromium, molybdenum, copper, and titanium; lithium and cesium Alkali metals such as sodium, and Group 2 metals such as calcium and magnesium can be used. A rare earth metal such as ytterbium (Yb) may be used as the transition metal. As the material, an alloy containing the above metals can be used, for example, MgAg, AlLi, etc. As the conductive compound, indium oxide-tin oxide (InTinOxide) Examples of conductive compounds include inorganic compounds such as graphene. Carbon-based materials may also be used. As mentioned above, by laminating multiple layers of these materials, Alternatively, one or both of the electrodes 101 and 102 may be formed using a metal oxide film.

[0125] The light emitted from the light-emitting layer 130 is emitted from one or both of the electrodes 101 and 102. Therefore, at least one of the electrodes 101 and 102 is visible. When a material with low light transmittance, such as a metal or alloy, is used for the electrode that extracts light, In this case, the electrode 1 is formed to a thickness that is thick enough to transmit visible light (for example, a thickness of 1 nm to 10 nm). Either or both of the electrode 101 and the electrode 102 may be formed.

[0126] <Hole injection layer> The hole injection layer 111 is formed by injecting 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, and is used in materials such as transition metal oxides and fluorine. It is formed by phthalocyanine derivatives or aromatic amines. 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 Materials such as self-doped polythiophenes, poly(ethylenediamines), can also be used. Typical examples include poly(oxythiophene) / poly(styrenesulfonic acid).

[0127] The hole injection layer 111 is made of a compound material including a hole transporting material and a material that exhibits electron accepting properties. Alternatively, a layer containing a material exhibiting electron accepting properties and a layer containing a material exhibiting electron accepting properties may be used. A stack of layers containing hole transport materials may also be used. It is possible to exchange charges in the presence of a magnetic field. Materials that exhibit electron-accepting properties include quinodimethane. Organic acceptors such as benzophenone derivatives, chloranil derivatives, 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 compounds have electron-withdrawing groups (halogen groups or cyano groups), such as hydroxybenzoates (HAT-CN). In addition, transition metal oxides, for example, oxides of metals from Groups 4 to 8, can be used. In general, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, These include tungsten oxide, manganese oxide, and rhenium oxide. Among these, it is preferred because it is stable, has low hygroscopicity, and is easy to handle.

[0128] As the hole transporting material, a material having a higher hole transporting property than an electron transporting property can be used. x10 -6 cm 2 It is preferable that the material has a hole mobility of 1 / Vs or more. The compounds are prepared using aromatic amines, carbazole derivatives, aromatic hydrocarbons, stilbene derivatives, etc. The hole transporting material may be a polymer compound.

[0129] As a material having high hole transporting properties, for example, aromatic amine compounds such as N,N' -Di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDP 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'-di Amine (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl [N-phenylamino]benzene (abbreviation: DPA3B), and the like.

[0130] Specific examples of carbazole derivatives include 3-[N-(9-phenylcarbazo] [N-phenyl-3-yl]-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzP CA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenyl Amino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N-(1-naphthyl) N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazol Examples include PCzPCN1 and the like.

[0131] Other carbazole derivatives include 4,4'-di(N-carbazolyl)biphene. Nyl (abbreviation: CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzoyl Zene (abbreviation: TCPB), 9-[4-(10-phenyl-9-anthryl)phenyl]- 9H-Carbazole (abbreviation: CzPA), 1,4-bis[4-(N-carbazolyl)phenyl] nyl]-2,3,5,6-tetraphenylbenzene, etc. can be used.

[0132] Furthermore, examples of aromatic hydrocarbons include 2-tert-butyl-9,10-di(2- naphthyl)anthracene (abbreviation: t-BuDNA), 2-tert-butyl-9,10- Di(1-naphthyl)anthracene, 9,10-bis(3,5-diphenylphenyl)anthracene thracene (abbreviation: DPPA), 2-tert-butyl-9,10-bis(4-phenylphenyl) phenyl)anthracene (abbreviation: t-BuDBA), 9,10-di(2-naphthyl)anthracene Helical anthracene (abbreviated as DNA), 9,10-diphenylanthracene (abbreviated as DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAnth), 9,10-bis(4- Methyl-1-naphthyl)anthracene (abbreviation: DMNA), 2-tert-butyl-9, 10-bis[2-(1-naphthyl)phenyl]anthracene, 9,10-bis[2-(1 -naphthyl)phenyl]anthracene, 2,3,6,7-tetramethyl-9,10-di( 1-naphthyl)anthracene, 2,3,6,7-tetramethyl-9,10-di(2-naphthyl)anthracene thyl)anthracene, 9,9'-bianthryl, 10,10'-diphenyl-9,9'- Bianthryl, 10,10'-bis(2-phenylphenyl)-9,9'-bianthryl , 10,10'-bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9' -Bianthryl, anthracene, tetracene, rubrene, perylene, 2,5,8,11- tetra(tert-butyl)perylene, etc. In addition, pentacene, Years etc. can also be used. In this way, 1 × 10 -6 cm 2 Hole mobility above / Vs It is more preferable to use an aromatic hydrocarbon having 14 to 42 carbon atoms.

[0133] The aromatic hydrocarbon may have a vinyl skeleton. Examples of aromatic hydrocarbons include 4,4'-bis(2,2-diphenylvinyl)biphenyl. (abbreviation: DPVBi), 9,10-bis[4-(2,2-diphenylvinyl)phenyl] anthracene (abbreviation: DPVPA), etc.

[0134] In addition, poly(N-vinylcarbazole) (abbreviation: PVK) and poly(4-vinyltriphenyl ether) Nylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenyl amino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide]( abbreviation: PTPDMA), poly[N,N'-bis(4-butylphenyl)-N,N'-bis Polymer compounds such as [(phenyl)benzidine] (abbreviation: Poly-TPD) can also be used. can.

[0135] <Hole transport layer> The hole transport layer 112 is a layer containing a hole transport material. The hole transport layer 112 is formed by injecting the hole into the hole injection layer 111. The highest occupied molecular orbital (H Highest Occupied Molecular Orbital (HOMO) It is preferable that the HOMO level is the same as or close to the HOMO level.

[0136] As the hole transport material, in addition to the materials exemplified as the material of the hole injection layer 111, An example of a substance with high transportability is 4,4'-bis[N-(1-naphthyl)-N-phenyl]. N,N'-bis(3-methylphenyl)-N ,N'-Diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD) , 4,4',4''-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4',4''-tris[N-(3-methylphenyl)-N-phenyl amino]triphenylamine (abbreviation: MTDATA), 4,4'-bis[N-(spiro- 9,9'-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: BSP B), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP) and other aromatic amine compounds can be used. The material is mainly 1×10 -6 cm 2 / Vs or more. Any substance other than these may be used as long as it has a higher hole transporting property than an electron transporting property. The layer containing a substance with a high hole transporting property may be a single layer or may be two or more layers containing the above substance. It may also be laminated on top.

[0137] In addition, a compound having a benzo[a]anthracene skeleton is used to form the hole transport layer 112. It may also be used as a material.

[0138] ≪Electron transport layer≫ The electron transport layer 118 is connected to the other of the pair of electrodes (electrode 101 or electrode 102) via the electron injection layer 119. The electron transport material has the function of transporting electrons injected from the electrode 102 to the light-emitting layer 130. As the material, a material with higher electron transportability than holes can be used, and the -6 cm 2 It is preferable that the material has an electron mobility of 1 / Vs or more. Gold with benzoquinoline, oxazole, or thiazole ligands metal complexes, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, pyridine derivatives Examples of suitable amine derivatives include pyrimidine derivatives, bipyridine derivatives, and pyrimidine derivatives.

[0139] For example, tris(8-quinolinolato)aluminum(III) (abbreviation: Alq), tri Bis(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq3), Bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq2 ), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum ( III) Metals with a quinoline or benzoquinoline skeleton, such as BAlq In addition, the layer is made of bis[2-(2-hydroxyphenyl)benzo[ [oxazolato]zinc(II) (abbreviation: Zn(BOX)2), bis[2-(2-hydroxybenzoyl) phenyl)benzothiazolato]zinc(II) (abbreviation: Zn(BTZ)2) Metal complexes having thiazole-based or thiazole-based ligands can also be used. In addition to the body, 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1, 3,4-Oxadiazole (abbreviation: PBD) and 1,3-bis[5-(p-tert-butyl) 1,3,4-oxadiazol-2-yl)benzene (abbreviation: OXD- 7), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl) )-1,2,4-triazole (abbreviation: TAZ), bathophenanthroline (abbreviation: BPh Other compounds that can be used include vasocuproine (abbreviated as BCP). The quality is mainly 1x10 -6 cm 2 It is a material with an electron mobility of 1 / Vs or more. Compounds having a zo[a]anthracene skeleton can also be suitably used. Any substance other than those mentioned above may be used for the electron transport layer as long as it has a high electron transporting property. The electron transport layer 118 may be not only a single layer, but also two or more layers made of the above-mentioned materials. It may also be a laminate.

[0140] In addition, a layer for controlling the movement of electron carriers is provided between the electron transport layer 118 and the light emitting layer 130. This is a method of adding a material with high electron transporting properties to a material with high electron trapping properties. A layer containing a small amount of This structure prevents electrons from penetrating the light-emitting layer. This is highly effective in suppressing problems that arise from the above (for example, a reduction in the device life).

[0141] ≪Electron injection layer≫ The electron injection layer 119 promotes electron injection by reducing the electron injection barrier from the electrode 102. For example, Group 1 metals, Group 2 metals, or their oxides and halides In addition, the electron transport material and the corresponding electron transport material can be used. A composite material of a material exhibiting electron donating properties can also be used. Examples of the metal include Group 1 metals, Group 2 metals, and oxides thereof.

[0142] The above-mentioned light-emitting layer, hole-injection layer, hole-transport layer, electron-transport layer, and electron-injection layer are These methods include vapor deposition (including vacuum deposition), inkjet printing, coating, and gravure printing. The light-emitting layer, the hole-injecting layer, the hole-transporting layer, the electron In addition to the above-mentioned materials, inorganic compounds or polymer compounds (oligonucleotides) can be used for the transport layer and the electron injection layer. A copolymer, such as a copolymer, a dendrimer, or a polymer, may also be used.

[0143] <Substrate> The light emitting element 150 may be fabricated on a substrate made of glass, plastic, or the like. The order of fabrication on the substrate can be from the electrode 101 side to the electrode 102 side. They may be laminated in order.

[0144] The substrate on which the light emitting element 150 can be formed is, for example, glass, quartz, or plastic. A flexible substrate may be used. It is a (flexible) substrate that can be used for example, polycarbonate, polyamide Examples of the substrate include plastic substrates made of inorganic films and inorganic vapor deposition films. In the manufacturing process of the light emitting element and the optical element, Any other device may be used as long as it functions as a light emitting element. Anything that has the function of protecting the element may be used.

[0145] For example, various substrates can be used to form the light emitting device 150. The types of substrates include: The substrate is not limited to a specific one. An example of the substrate is a semiconductor substrate (e.g., a single crystal crystal substrate or silicon substrate), SOI substrate, glass substrate, quartz substrate, plastic substrate, gold Metal substrate, stainless steel substrate, substrate with stainless steel foil, tungsten Tungsten substrate, substrate with tungsten foil, flexible substrate, laminated film, fiber Examples of glass substrates include paper or substrate films containing barium-based materials. Examples include borosilicate glass, aluminoborosilicate glass, and soda-lime glass. Examples of flexible substrates, laminated films, and base films include the following: For example, polyethylene terephthalate (PET), polyethylene naphthalate (P EN), polyethersulfone (PES), polytetrafluoroethylene (PTFE) A typical example is plastic. Another example is resin such as acrylic. Alternatively, for example, polypropylene, polyester, polyvinyl fluoride, or polychloride Examples include polyamide, polyimide, aramid, and epoxy. Examples include glass, inorganic vapor deposition film, and paper.

[0146] Alternatively, a flexible substrate may be used as the substrate, and the light emitting element may be formed directly on the flexible substrate. Alternatively, a release layer may be provided between the substrate and the light-emitting element. After a part or all of a device is completed, it is separated from the substrate and used to transfer it to another substrate. In this case, the light-emitting element can be transferred onto a substrate having poor heat resistance or a flexible substrate. The peeling layer may have 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, etc., can be used.

[0147] That is, a light emitting element is formed using a certain substrate, and then the light emitting element is transferred to another substrate. The light emitting element may be disposed on another substrate. In addition to the substrates mentioned above, cellophane substrates, stone substrates, wood substrates, fabric substrates (natural fibers (silk, cotton, Hemp), synthetic fibers (nylon, polyurethane, polyester) or regenerated fibers (acetate (including cellulose, cupro, rayon, recycled polyester, etc.), leather substrate, rubber substrate, etc. By using these substrates, it is possible to produce light emitting elements that are durable and highly heat resistant. The light emitting element may be a small, lightweight, or thin light emitting element.

[0148] Furthermore, for example, a field effect transistor (FET) is formed on the above-mentioned substrate, and the FET and The light emitting element 150 may be fabricated on the electrically connected electrodes. In this way, an active matrix display device that controls the driving of the light emitting element 150 can be fabricated.

[0149] Note that one embodiment of the present invention has been described in this embodiment. However, the present invention is not limited to these embodiments. For example, in one embodiment of the present invention, the light emitted from the EL layer is not due to triplet-triplet annihilation. The proportion of delayed fluorescence components due to this is 20% or more, and the emission spectrum peaks in blue. However, one embodiment of the present invention is not limited to this. Alternatively, optionally, in one embodiment of the present invention, the EL layer may exhibit delayed fluorescence. The proportion of the light component does not have to be 20% or more. Or, the emission spectrum peaks in blue. Alternatively, it may be possible to have at least one wavelength in the wavelength band of 400 nm or more and 550 nm or less. Alternatively, for example, in one embodiment of the present invention, The EL layer has an energy level between the lowest singlet excited energy level and the lowest triplet excited energy level. The EL layer contains an organic compound having an energy difference of 0.5 eV or more, and the light emitted by the EL layer is a delayed fluorescent compound. The ratio of the luminescent element is 20% or more, and the luminescent element has a blue emission spectrum peak. Although examples have been given, one aspect of the present invention is not limited thereto. In accordance with this, in one embodiment of the present invention, for example, the EL layer has a lowest singlet excited energy level and The organic compound whose energy difference between the lowest triplet excited energy level and Alternatively, for example, in one embodiment of the present invention, the EL layer may not include a benzo[a]an The EL layer contains a compound having a thracene skeleton, and the emission of the EL layer is determined by the proportion of delayed fluorescent components. Although an example in which the ratio is 20% or more is shown, one embodiment of the present invention is not limited to this. In some cases, the EL layer may not contain a compound having a benzo[a]anthracene skeleton. stomach.

[0150] As described above, the structure shown in this embodiment mode can be used in appropriate combination with other embodiment modes. Cut.

[0151] (Embodiment 2) In this embodiment, compounds that can be suitably used for the light-emitting element of one embodiment of the present invention will be described. The following explains the details.

[0152] The compound of the present embodiment has at least one benzo[a]anthracene skeleton at the 7-position. A compound having a carbazole derivative in which a carbazole skeleton is bonded via an arylene group. The benz[a]anthracene compound exhibits delayed fluorescence due to TTA. Since the proportion of the component is high, the benzo[a]anthracene compound is used in a light-emitting device. By using the benzo[a], a light-emitting element with good luminous efficiency can be manufactured. ]anthracene compounds have a wide band gap, so the benz[a]anthracene By using the compound in a light-emitting element, a light-emitting element with high luminous efficiency can be manufactured. Furthermore, a light-emitting element that emits blue light and has particularly good luminous efficiency can be manufactured. Since the benzo[a]anthracene compound has excellent carrier transport properties, the benzo[a]anthracene compound By using an anthracene compound in a light-emitting element, a light-emitting element with a low driving voltage can be manufactured. In addition, the benz[a]anthracene compound is excellent in resistance to repeated oxidation and reduction. Since the benz[a]anthracene compound has excellent resistance, it can be used in a light-emitting device. As a result, a light-emitting element with a long driving life can be manufactured. By using this compound in a light-emitting device, a high-performance light-emitting device with excellent light-emitting properties can be produced. It is possible.

[0153] When the arylene group has 6 to 13 carbon atoms, the benz[a]anthracene The compound is a low molecular weight compound with a relatively low molecular weight, so it is suitable for vacuum deposition (relatively low temperature and true deposition). Generally, if the molecular weight is low, the heat resistance after film formation is poor. However, the benz[a]anthracene compound has a benz[a]anthracene skeleton. Due to the influence of the rigid skeleton of the copolymer, it has the advantage that sufficient heat resistance can be ensured even with a low molecular weight.

[0154] In addition, the carbazole skeleton is connected to the 7-membered benzo[a]anthracene skeleton via an arylene group. By bonding to the benzo[a]anthracene position, the compound has excellent carrier transport properties. Therefore, the light-emitting element using the benz[a]anthracene compound has a low It can be driven by a voltage.

[0155] In addition, the benz[a]anthracene compound is, in other words, benz[a]anthracene Benz[a]anthracene compounds are compounds in which an arylcarbazole derivative is bonded to the anthracene skeleton. When synthesizing the benz[a]anthracene compound, it is necessary to synthesize it with high purity. Since it is easy to do this, it is possible to suppress deterioration due to impurities. From the viewpoint of stability and reliability of properties, aryl groups bonded to the benz[a]anthracene skeleton are The aryl group of the carbazole derivative preferably has 6 to 13 carbon atoms. As described above, the benz[a]anthracene compound can be vacuum-deposited at a relatively low temperature. Therefore, deterioration such as thermal decomposition during vapor deposition is unlikely to occur. The driving voltage is also excellent. This is because the benz[a]anthracene compound It has a molecular structure in which a carbazole skeleton is bonded to the 7-position of the anthracene skeleton via an arylene group. This is also due to the fact that electrochemical stability and high carrier transport properties are obtained.

[0156] In addition, the carbazole skeleton is connected to the benzo[a]anthracene via an arylene group at the 9-position. Benz[a]anthracene compounds bonded to the anthracene skeleton have a wider band gap. In particular, it can be suitably used for a light-emitting element that emits high-energy light such as blue light. Between the carbazole skeleton and the benz[a]anthracene skeleton, a phenylene group or The bond is preferably via an arylene group such as a naphthylene group.

[0157] For the reasons mentioned above, the 9-position of the carbazole skeleton and the benzo[a Benz[a]anthracene compounds in which the 7-position of the α-anthracene skeleton is bonded are more preferred. This compound has a (9-carbazolyl)aryl group attached to the 7-position of the benz[a]anthracene skeleton. It can be said that the benz[a]anthracene compound having the above structure is more preferable. From the viewpoint of the stability of the light-emitting device and the stability of the benzo[a]anthracene skeleton, The aryl group in the (9-carbazolyl)aryl group preferably has 6 to 13 carbon atoms. That is, the benz[a]anthracene compound has the above-mentioned advantages of ease of deposition and electrical conductivity. In addition to the chemical and pneumatic stability and carrier transport properties, the 9-carbazolyl group structure has a beneficial effect on the band structure. It also has the property of having a wide gap. The benz[a]anthracene compound is used as a guest material, and the luminescent material is used as a guest material. It is particularly advantageous when added to a layer containing the compound. It is preferable to use it as such.

[0158] <Compound Example 1> The benz[a]anthracene compound is a benzo[a]anthracene compound represented by the following general formula (G1): ] anthracene compounds.

[0159] [ka]

[0160] In the above general formula (G1), A represents a substituted or unsubstituted carbazolyl group. When the carbazolyl group has a substituent, the substituent is an alkyl group having 1 to 6 carbon atoms. a cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 6 to 12 carbon atoms; The following aryl groups can also be selected as substituents. Specifically, the alkyl group includes a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, and the like. Examples of the alkyl group include a 3-carbon alkyl group, a tert-butyl group, and an n-hexyl group. Specific examples of the cycloalkyl group of the sixth to sixth embodiments include a cyclopropyl group, a cyclobutyl group, cyclopentyl group, cyclohexyl group, etc. Specific examples of the aryl group of 2 include a phenyl group, a naphthyl group, and a biphenyl group. It can be done.

[0161] Also, R 1 ~R 10 are each independently 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; R 11 is hydrogen, an alkyl group having 1 to 6 carbon atoms, It represents any one of the cycloalkyl groups of any one of the groups shown in any one of the preceding paragraphs, or a substituted or unsubstituted phenyl group. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an ethyl ... Examples include isopropyl, butyl, isobutyl, tert-butyl, and n-hexyl groups. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include cycloalkyl groups such as Examples of the cyclopropyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. The aryl group having 6 to 13 carbon atoms includes a phenyl group, a naphthyl group, Specific examples include a biphenyl group and a fluorenyl group. The aryl group and phenyl group may have a substituent, and the substituents may be bonded to each other to form a ring. The substituent may be an alkyl group having 1 to 6 carbon atoms, an alkyl group having 3 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms. or an aryl group having 6 to 12 carbon atoms may also be selected as a substituent. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, and a propyl group. propyl, isopropyl, butyl, isobutyl, tert-butyl, n-hexyl Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include: Examples of the cyclopropyl group include cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl groups. Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a naphthyl group, and the like. Specific examples include a phenyl group and a biphenyl group.

[0162] Furthermore, Ar represents an arylene group having 6 to 13 carbon atoms, and the arylene group has a substituent. The substituents may be bonded to each other to form a ring. For example, the carbon atom at the 9th position of the fluorenyl group has two phenyl groups as substituents, In some cases, phenyl groups bond together to form a spirofluorene structure. Examples of the arylene group having 6 to 13 carbon atoms include a phenylene group, a naphthylene group, Specific examples include a biphenylene group and a fluorenediyl group. When the arylene group has a substituent, the substituent is preferably 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 may also be used as a substituent. Specific examples of the alkyl group having 1 to 6 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group Examples of the cycloalkyl group include a cycloalkyl group having 3 to 6 carbon atoms and an n-hexyl group. Specific examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl ... Examples of the aryl group having 6 to 12 carbon atoms include a hexyl group and the like. Specific examples include a phenyl group, a naphthyl group, and a biphenyl group.

[0163] <Compound Example 2> In addition, in the benz[a]anthracene compound of the present embodiment, The structure in which the group is bonded to the benz[a]anthracene skeleton via an arylene group at the 9-position Benz[a]anthracene compounds with a wide band gap are particularly suitable for blue light. Since it can be suitably used for a light-emitting element that emits light with high energy, such as In addition, since the benz[a]anthracene compound has excellent carrier transport properties, This is a preferable configuration because a light-emitting element using this compound can be driven at a low voltage. The benz[a]anthracene compound is a benzo[a]anthracene compound represented by the following general formula (G2): It is a mixture.

[0164] [ka]

[0165] In the above general formula (G2), R 1 ~R 10 , R 21 ~R 28 are each independently , hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a carbon R represents a substituted or unsubstituted aryl group having a number of 6 to 13. 11 is water alkyl groups having 1 to 6 carbon atoms, cycloalkyl groups having 3 to 6 carbon atoms, or substituted or unsubstituted alkyl groups. The alkyl group having 1 to 6 carbon atoms is specifically a phenyl group or an unsubstituted phenyl group. The following groups are available: methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t Examples of the alkyl group include an ethyl group, an n-butyl group, and an n-hexyl group. Specific examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclopentyl group. Examples of the alkyl group include aryl groups having 6 to 13 carbon atoms, such as butyl groups and cyclohexyl groups. Specific examples of the alkyl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. Furthermore, the above-mentioned aryl group and phenyl group may have a substituent. The substituents may be bonded to each other to form a ring. an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a cycloalkyl group having 6 to 1 carbon atoms; The aryl group of 2 can also be selected as a substituent. Specifically, the alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, and isobutyl groups. Examples of the alkyl group include ethyl, tert-butyl, and n-hexyl groups. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, a cyclobutyl group, cyclopentyl group, cyclohexyl group, etc. Specific examples of the aryl group of 2 include a phenyl group, a naphthyl group, and a biphenyl group. It can be done.

[0166] Furthermore, Ar represents an arylene group having 6 to 13 carbon atoms, and the arylene group has a substituent. The substituents may be bonded to each other to form a ring. For example, the carbon atom at the 9th position of the fluorenyl group has two phenyl groups as substituents, In some cases, phenyl groups bond together to form a spirofluorene structure. Examples of the arylene group having 6 to 13 carbon atoms include a phenylene group, a naphthylene group, Specific examples include a biphenylene group and a fluorenediyl group. When the arylene group has a substituent, the substituent is preferably 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 may also be used as a substituent. Specific examples of the alkyl group having 1 to 6 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group Examples of the cycloalkyl group include a cycloalkyl group having 3 to 6 carbon atoms and an n-hexyl group. Specific examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl ... Examples of the aryl group having 6 to 12 carbon atoms include a hexyl group and the like. Specific examples include a phenyl group, a naphthyl group, and a biphenyl group.

[0167] <Compound Example 3> In addition, in the benz[a]anthracene compound of the present embodiment, The benz[a]anthracene skeleton is connected to the 1st to 4th positions of the arylene group. Benz[a]anthracene compounds with a bonded structure have excellent carrier transport properties. Therefore, a light-emitting element using this can be driven at a low voltage, which is a preferable structure. The benz[a]anthracene compound is a benz[a]anthracene compound represented by the following general formula (G3): It is a sen compound.

[0168] [ka]

[0169] In the above general formula (G3), R 1 ~R 10 , R 31 ~R 35 are each independently , hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a carbon R represents a substituted or unsubstituted aryl group having a number of 6 to 13. 11 is water alkyl groups having 1 to 6 carbon atoms, cycloalkyl groups having 3 to 6 carbon atoms, or substituted or unsubstituted alkyl groups. The alkyl group having 1 to 6 carbon atoms is specifically a phenyl group or an unsubstituted phenyl group. The following groups are available: methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t Examples of the alkyl group include an ethyl group, an n-butyl group, and an n-hexyl group. Specific examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclopentyl group. Examples of the alkyl group include aryl groups having 6 to 13 carbon atoms, such as butyl groups and cyclohexyl groups. Specific examples of the alkyl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. Furthermore, the above-mentioned aryl group and phenyl group may have a substituent. The substituents may be bonded to each other to form a ring. an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a cycloalkyl group having 6 to 1 carbon atoms; The aryl group of 2 can also be selected as a substituent. Specifically, the alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, and isobutyl groups. Examples of the alkyl group include ethyl, tert-butyl, and n-hexyl groups. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, a cyclobutyl group, cyclopentyl group, cyclohexyl group, etc. Specific examples of the aryl group of 2 include a phenyl group, a naphthyl group, and a biphenyl group. It can be done.

[0170] Furthermore, Ar represents an arylene group having 6 to 13 carbon atoms, and the arylene group has a substituent. The substituents may be bonded to each other to form a ring. For example, the carbon atom at the 9th position of the fluorenyl group has two phenyl groups as substituents, In some cases, phenyl groups bond together to form a spirofluorene structure. Examples of the arylene group having 6 to 13 carbon atoms include a phenylene group, a naphthylene group, Specific examples include a biphenylene group and a fluorenediyl group. When the arylene group has a substituent, the substituent is preferably 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 may also be used as a substituent. Specific examples of the alkyl group having 1 to 6 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group Examples of the cycloalkyl group include a cycloalkyl group having 3 to 6 carbon atoms and an n-hexyl group. Specific examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl ... Examples of the aryl group having 6 to 12 carbon atoms include a hexyl group and the like. Specific examples include a phenyl group, a naphthyl group, and a biphenyl group.

[0171] In addition, in the benz[a]anthracene compound of the present embodiment, The group is a substituted or unsubstituted phenylene group or a substituted or unsubstituted biphenyldiyl group. benzo[a]anthracene skeleton bonded to the benzo[a]anthracene skeleton via either Anthracene compounds have improved stability and can be synthesized with high purity. This is a preferred configuration. In addition, the benz[a]anthracene compound has a carrier transport property. Since this has excellent properties, a light-emitting element using this can be driven at a low voltage.

[0172] In addition, in the benz[a]anthracene compound of the present embodiment, The group is bonded to the benz[a]anthracene skeleton via a substituted or unsubstituted m-phenylene group The benzo[a]anthracene compound with this structure has a wider band gap, In particular, it can be suitably used for light-emitting elements that emit high energy light such as blue light. This is a preferred configuration.

[0173] <Compound Example 4> In addition, in the benz[a]anthracene compound of the present embodiment, The group is bonded to the benz[a]anthracene skeleton via a substituted or unsubstituted p-phenylene group The benz[a]anthracene compound having the above structure has improved stability and high purity. This is a preferred configuration because it can be synthesized. The compound is a benzo[a]anthracene compound represented by the following general formula (G4) or general formula (G5). It is a mixture.

[0174] [ka]

[0175] In the above general formula (G4), R 1 ~R 10 , R 21 ~R 28 , and R 41 ~R 44 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a cyclo group having 3 to 6 carbon atoms, represents either an alkyl group or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; Also, R 11 is hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, It represents either an alkyl group or a substituted or unsubstituted phenyl group. Specific examples of alkyl groups include methyl, ethyl, propyl, isopropyl, and butyl groups. Examples of the alkyl group include an isobutyl group, a tert-butyl group, and an n-hexyl group. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, ... Examples of the alkyl group include a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. Examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluoro group, and the like. Specific examples include olefinyl groups. Furthermore, the above-mentioned aryl groups and phenyl groups can be used. The yl group may have substituents, and the substituents may be bonded to each other to form a ring. The substituents include alkyl groups having 1 to 6 carbon atoms and cycloalkyl groups having 3 to 6 carbon atoms. or an aryl group having 6 to 12 carbon atoms can also be selected as a substituent. Specific examples of the alkyl groups of the first to sixth groups include a methyl group, an ethyl group, a propyl group, an isopropyl group, and Examples include butyl, isobutyl, tert-butyl, and n-hexyl groups. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include cyclopropyl. cyclobutyl, cyclopentyl, cyclohexyl, etc. The aryl group having 6 to 12 carbon atoms includes a phenyl group, a naphthyl group, a biphenyl group, and the like. Specific examples include groups such as R 1 ~R 10 All of the However, it is advantageous in terms of ease of synthesis and the cost of raw materials.

[0176] [ka]

[0177] In the above general formula (G5), R 1~R 10 , R 31 ~R 35 , and R 41 ~R 44 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, a cyclo group having 3 to 6 carbon atoms, represents either an alkyl group or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; Also, R 11 is hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, It represents either an alkyl group or a substituted or unsubstituted phenyl group. Specific examples of alkyl groups include methyl, ethyl, propyl, isopropyl, and butyl groups. Examples of the alkyl group include an isobutyl group, a tert-butyl group, and an n-hexyl group. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, ... Examples of the alkyl group include a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. Examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluoro group, and the like. Specific examples include olefinyl groups. Furthermore, the above-mentioned aryl groups and phenyl groups can be used. The yl group may have substituents, and the substituents may be bonded to each other to form a ring. The substituents include alkyl groups having 1 to 6 carbon atoms and cycloalkyl groups having 3 to 6 carbon atoms. or an aryl group having 6 to 12 carbon atoms can also be selected as a substituent. Specific examples of the alkyl groups of the first to sixth groups include a methyl group, an ethyl group, a propyl group, an isopropyl group, and Examples include butyl, isobutyl, tert-butyl, and n-hexyl groups. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include cyclopropyl. cyclobutyl, cyclopentyl, cyclohexyl, etc. The aryl group having 6 to 12 carbon atoms includes a phenyl group, a naphthyl group, a biphenyl group, and the like. Specific examples include groups such as R 1 ~R 10 All of the However, it is advantageous in terms of ease of synthesis and the cost of raw materials.

[0178] <Examples of substituents> In the general formula (G1), the carbazolyl group represented by A includes, for example, the following structure: Groups represented by the formulae (Cz-1) to (Cz-7) can be used. The groups that can be used are not limited to these.

[0179] [ka]

[0180] In the above general formulae (G1) to (G3), the arylene group represented by Ar can be, for example, For example, groups represented by the following structural formulas (Ar-1) to (Ar-18) can be used. However, the groups that can be used as Ar are not limited to these.

[0181] [ka]

[0182] In addition, R in the above general formulas (G1) to (G5) 1 ~R 10 , general formula (G2) and (G4 )R 21 ~R 28 , R in general formulas (G3) and (G5) 31 ~R 35 , general formula (G4 ) and (G5) R 41 ~R 44 The alkyl group or aryl group represented by the formula (I) is, for example, Groups represented by the following structural formulas (R-1) to (R-29) can be used. The groups that can be used as the alkyl group or aryl group are not limited to these.

[0183] [ka]

[0184] In addition, R in the above general formulas (G1) to (G5) 11 an alkyl group represented by The group may be, for example, a group represented by the above structural formulas (R-1) to (R-22). However, the groups that can be used as alkyl groups or phenyl groups are not limited to these. do not have.

[0185] <Specific examples of compounds> The benz[a]anthracene compounds represented by the above general formulas (G1) to (G5) Examples of the physical structure include substances represented by the following structural formulas (100) to (125). The benzo[a]anthracene compounds represented by the general formulas (G1) to (G5) are The compounds are not limited to the following examples.

[0186] [ka]

[0187] [ka]

[0188] [ka]

[0189] [ka]

[0190] As described above, the benz[a]anthracene compound according to the present embodiment can be produced by TTA. Since the proportion of delayed fluorescent components is high, it is suitable as a host material for light-emitting devices. As a result, a light-emitting element with high luminous efficiency can be manufactured. Benz[a]anthracene compounds have a wide band gap and are therefore particularly suitable as blue light-emitting elements. This makes it suitable as a host material for electrons and a carrier transport material. In addition, the benzo[a]anthracene compound of the present embodiment can be used to fabricate a color light emitting device. Sen compounds have excellent carrier transport properties and are therefore suitable as host materials for light-emitting devices and as carrier transport materials. This makes it possible to fabricate light-emitting devices with low driving voltage. In addition, the benz[a]anthracene compound of the present embodiment is oxidized and reduced repeatedly. Since the benz[a]anthracene compound has good durability, it can be used in a light-emitting device. As a result, a light-emitting element with a long driving life can be manufactured. The benzo[a]anthracene compound is a suitable material for use in a light-emitting device.

[0191] The benz[a]anthracene compound in this embodiment is prepared by a vapor deposition method (vacuum vapor deposition method The film can be formed by using methods such as inkjet printing, coating, and gravure printing. Cut.

[0192] Note that the compound described in this embodiment may be appropriately combined with any of the structures described in other embodiments. It can be used.

[0193] (Embodiment 3) In this embodiment, a benzo[a]anthracene compound represented by general formula (G1) is synthesized. The synthesis method of benz[a]anthracene compounds is explained below. For example, the following synthesis reaction can be carried out to obtain a compound represented by the general formula (G Benz[a]anthracene compounds represented by the formula (1) can be synthesized. The synthesis method of the benz[a]anthracene compound, which is one embodiment of the present invention, is not limited to the following synthesis method. I can't.

[0194] The compound represented by general formula (G1) can be synthesized as shown in the following synthesis scheme (A-1). That is, the benzo[a]anthracene compound (a1) and the aryl compound ( a2) can be coupled to obtain a compound of general formula (G1). do.

[0195] [ka]

[0196] In the synthetic scheme (A-1), A represents a substituted or unsubstituted carbazolyl group, X 1 and X 2 are each independently a halogen group, a trifluoromethanesulfonyl group, a boron group, represents a carboxylic acid group, an organic boron group, a magnesium halide group, an organic tin group, or the like. X 1 Gaha When the alkylene group or trifluoromethanesulfonyl group, X 2 is a boronic acid group, organic boron group, magnesium halide group, or organotin group. 1 is a boronic acid group, organic When the group is a boron group, a magnesium halide group, or an organic tin group, X 2 is a halogen group or It represents a trifluoromethanesulfonyl group.

[0197] In the synthetic scheme (A-1), R 1 ~R 10 are independently hydrogen, carbon number an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a represents either a substituted or unsubstituted aryl group, and R 11 is hydrogen, carbon number 1 to 6 an alkyl group, a cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted phenyl group; Ar represents an arylene group having 6 to 13 carbon atoms, The group may have substituents, and the substituents may be bonded to each other to form a ring.

[0198] In the synthetic scheme (A-1), a palladium-catalyzed Suzuki-Miyaura coupling reaction When responding, X 1 and X 2 is a halogen group, a boronic acid group, an organoboron group, or a triflate The halogen group is preferably iodine, bromine, or chlorine. In this reaction, bis(dibenzylideneacetone)palladium(0) and palladium acetate are used. (II), [1,1-bis(diphenylphosphino)ferrocene]palladium(II) di Palladium compounds such as chloride, tetrakis(triphenylphosphine)palladium(0) and tri(tert-butyl)phosphine, tri(n-hexyl)phosphine, trisilyl Dicyclohexylphosphine, Di(1-adamantyl)-n-butylphosphine, 2-dicyclohexyl 2',6'-dimethoxybiphenyl, tri(ortho-tolyl)phosphino Ligands such as sphingosines can be used. and inorganic bases such as potassium carbonate, cesium carbonate, and sodium carbonate. In this reaction, toluene, xylene, benzene, methionine, Use ethylene, tetrahydrofuran, dioxane, ethanol, methanol, water, etc. The reagents that can be used in this reaction are not limited to these. do not have.

[0199] The reaction performed in the synthetic scheme (A-1) is limited to the Suzuki-Miyaura coupling reaction. Instead of organotin compounds, the Migita-Kosugi-Stille coupling reaction and Grignard coupling reaction Kumada-Tamao-Corleau coupling reaction using a molten zinc compound, and Negishi coupling reaction using an organozinc compound. Coupling reactions and the like can be used.

[0200] As described above, the benz[a]anthracene compound of general formula (G1) can be synthesized. Cut.

[0201] Note that the compound described in this embodiment may be appropriately combined with any of the structures described in other embodiments. It can be used.

[0202] (Fourth embodiment) In this embodiment, a photogenerator using the benz[a]anthracene compound described in Embodiment 2 is used. An example of the configuration of the optical element will be described below with reference to FIGS.

[0203] <Configuration example 1 of light-emitting element> The light-emitting element 152 in FIG. 3 has an EL layer 105 between a pair of electrodes. The benzo[a]anthracene compound described in the second embodiment is used in any of the layers. It is a light-emitting element.

[0204] The EL layer 105 is configured to include the hole emitting layer 135 shown in the first embodiment. The structure includes an injection layer 111, a hole transport layer 112, an electron transport layer 118, and an electron injection layer 119. The laminated structure of the EL layer 105 is not limited to this.

[0205] In addition, the pair of electrodes (electrode 101 and electrode 102) and the hole injection layer 1 11. The hole transport layer 112, the electron transport layer 118, and the electron injection layer 119 are the same as those in the first embodiment. The guest material 137 used in the light-emitting layer 135 can be The guest material 132 described in Embodiment 1 can be used.

[0206] The benzo[a]anthracene compound described in the second embodiment emits light by TTA. Since the proportion of delayed fluorescent components is high, it is particularly preferable to use the delayed fluorescent component as the host material 136 in the light-emitting element 152. That is, the benz[a]anthracene compound described in the second embodiment is preferably used. By using it as the host material 136 of the optical element 152, a light-emitting element with good luminous efficiency can be fabricated. In addition, the EL layer 105 can be formed by using the benz[a]anthracene compound. It is possible to fabricate a light-emitting device in which the proportion of delayed fluorescent components in the emitted light is 20% or more. In addition, since the benz[a]anthracene compound has a wide band gap, In particular, it is suitable as a host material or a carrier transport material for a blue light-emitting device. By using the configuration of the embodiment, the light emission efficiency is good and the emission spectrum peaks in blue. In addition, the benz[a]anthracene compound Since it has excellent carrier transport properties, it is suitable as a host material or a carrier transport material for a light-emitting element. Therefore, by using the structure of this embodiment, a light-emitting element with low driving voltage can be obtained. The benz[a]anthracene compound can be prepared by oxidation and reduction. Since the material has good resistance to repeated heating and cooling, it is possible to fabricate a light-emitting device with a good operating life. Cut.

[0207] <Configuration example 2 of light-emitting element> Next, an example of a configuration different from that of the light-emitting element shown in FIG. 3 will be described below with reference to FIG.

[0208] 4 is a cross-sectional view illustrating a light-emitting element according to one embodiment of the present invention. The same hatch pattern is used for parts with the same function as the symbols shown, and in some cases the symbols are omitted. In addition, parts having similar functions are given similar reference numerals, and detailed explanations thereof will be omitted. It may be omitted.

[0209] The light emitting element 250 shown in FIG. 4 is a bottom-emitting element that extracts light toward the substrate 200. However, one embodiment of the present invention is not limited thereto, and the light-emitting element may be The light emitted from the top surface (top emission) is extracted in the direction opposite to the substrate 200. Both sides of the substrate 200 on which the optical element or light emitting element is formed are taken out. It may also be a dual emission type light emitting element.

[0210] The light emitting element 250 has an electrode 101 and an electrode 102 on a substrate 200. Between the electrode 101 and the electrode 102, there are a light-emitting layer 123B, a light-emitting layer 123G, and a light-emitting layer 123R. , a hole injection layer 111, a hole transport layer 112, an electron transport layer 118, and an electron and a child injection layer 119.

[0211] When the light emitting element is a bottom emission type, the electrode 101 has a function of transmitting light. In addition, the electrode 102 preferably has a function of reflecting light.

[0212] The light-emitting element 250 shown in FIG. 4 includes an area 221B sandwiched between the electrode 101 and the electrode 102, The partition wall 140 is provided between the region 221G and the region 221R. The partition wall 140 is an insulating The partition wall 140 covers the end of the electrode 101 and has an opening that overlaps the electrode. By providing the partition wall 140, the electrodes 101 of the substrate 200 in each region are It is possible to separate it into islands.

[0213] The light-emitting layers 123B, 123G, and 123R each have a function of exhibiting a different color. For example, the light-emitting layer 123B is preferably blue, and the light-emitting layer 1 The light-emitting layer 23G has a light-emitting material that can emit green light, and the light-emitting layer 123R has a light-emitting material that can emit red light. The optical element 250 can be used in a display device capable of full color display. The thicknesses of the light-emitting layers may be the same or different.

[0214] In addition, at least one of the light-emitting layers 123B, 123G, and 123R Therefore, it is preferable to have the benz[a]anthracene compound shown in Embodiment 2. By doing so, the proportion of delayed fluorescent components in the light emitted by the light-emitting layer is 20% or more. In particular, a light-emitting element having a certain region can be fabricated. By using the benzo[a]anthracene compound shown in 2, blue light was emitted with good luminous efficiency. Light emitting devices can be fabricated that have optical spectrum peaks.

[0215] In addition, any one or more of the light-emitting layer 123B, the light-emitting layer 123G, and the light-emitting layer 123R The light-emitting layer may have a structure in which two or more layers are laminated.

[0216] As described above, at least one light-emitting layer contains the benzo[a]anthracene compound shown in the second embodiment. The light-emitting element 250 having the light-emitting layer containing the sene compound is provided in each sub-pixel of the pixel of the display device. By using the light-emitting element, a display device with high luminous efficiency can be manufactured. A display device having the 250 can reduce power consumption.

[0217] <Configuration example 3 of light-emitting element> Next, regarding examples of configurations different from those of the light-emitting elements shown in FIGS. 3 and 4, we will use FIGS. 5(A) and 5(B) to explain the configurations. The following explanation will be given.

[0218] 5(A) and 5(B) are cross-sectional views illustrating a light-emitting element according to one embodiment of the present invention. )(B), the parts having the same functions as those shown in FIGS. 3 and 4 are denoted by the same symbols. In addition, parts with similar functions will be marked with similar symbols. In some cases, detailed explanations of these components will be omitted.

[0219] 5(A) and 5(B), a plurality of light-emitting layers are stacked between a pair of electrodes with a charge generating layer 115 interposed therebetween. The light emitting element 252 shown in FIG. A top-emission type light-emitting element that extracts light in the opposite direction to 00, Fig. 5( The light emitting element 254 shown in FIG. 1B is a bottom emission element that extracts light toward the substrate 200. However, one embodiment of the present invention is not limited thereto, and the light-emitting element The light emitted from the substrate 200 on which the light emitting element is formed is extracted from both the upper and lower sides of the substrate 200. It may be of the dual emission type.

[0220] The light emitting element 252 and the light emitting element 254 are formed by forming an electrode 101, an electrode 102, and The electrode 103 and the electrode 104 are provided. Between the electrode 102 and the electrode 103, and between the electrode 102 and the electrode 104, a light-emitting layer 160 and an electrode The organic EL device has a charge generating layer 115 and a light emitting layer 170. The organic EL device also has a hole injection layer 111 and a hole transport layer 112, an electron transport layer 113, an electron injection layer 114, a hole injection layer 116, and a hole transport layer 117, an electron transport layer 118, and an electron injection layer 119.

[0221] The electrode 101 includes a conductive layer 101a and a conductive layer 101b that is in contact with the conductive layer 101a. The electrode 103 includes a conductive layer 103a and a conductive layer 103b on and in contact with the conductive layer 103a. The electrode 104 has a conductive layer 104a and a conductive layer 103b on the conductive layer 104a. and an insulating layer 104b.

[0222] The light emitting element 252 shown in FIG. 5(A) and the light emitting element 254 shown in FIG. 5(B) are formed by using an electrode 10 1 and electrode 102, and the area 222B sandwiched between electrode 102 and electrode 103. A partition wall 1 is provided between the region 222G and the region 222R sandwiched between the electrode 102 and the electrode 104. The partition wall 140 has insulating properties. The partition wall 140 is provided between the electrode 101 and the electrode 103. The partition wall 140 covers the edge of the electrode 104 and has an opening overlapping the electrode. By this, the electrodes on the substrate 200 in each region can be separated into islands. It becomes Noh.

[0223] The light emitting element 252 and the light emitting element 254 are formed in the region 222B, the region 222G, and the region The optical elements 224B and 222R are arranged in the direction in which the light emitted from the optical elements 224B and 222R is extracted. 24G, and a substrate 220 having optical elements 224R. The light emitted from each region is The light emitted from the region 222B is emitted to the outside of the light emitting element through each optical element. The light emitted from the region 222G is emitted through the optical element 224B. The light emitted from the region 222R through the optical element 224R is then emitted through the optical element 224G. will be done.

[0224] Furthermore, the optical elements 224B, 224G, and 224R are configured to For example, the optical element 224B has a function of selectively transmitting light of a specific color. The light emitted from the region 222B through the optical element 22 is blue light. The light emitted from the area 222G via the optical element 4G is green light. The light emitted from the region 222R via the element 224R is red light.

[0225] In addition, in Fig. 5(A) and (B), the light emitted from each region via each optical element is Light exhibiting color (B), light exhibiting green (G), and light exhibiting red (R), respectively. This is shown schematically by dashed arrows.

[0226] In addition, a light-shielding layer 223 is provided between each optical element. The light-shielding layer 223 is formed to prevent light from entering from adjacent regions. It should be noted that the light-shielding layer 223 may not be provided. stomach.

[0227] <Microcavity> Furthermore, the light emitting element 252 and the light emitting element 254 have a microcavity structure.

[0228] The light emitted from the light-emitting layer 160 and the light-emitting layer 170 is incident on a pair of electrodes (for example, the electrode 101 In the light emitting element 252 and the light emitting element 254, the resonance occurs between the electrode 102 and the electrode 102. The thickness of the conductive layers (conductive layer 101b, conductive layer 103b, and conductive layer 104b) is adjusted in the region. This makes it possible to intensify the wavelength of light emitted from the light-emitting layer 160 and the light-emitting layer 170. In each region, the thickness of at least one of the hole injection layer 111 and the hole transport layer 112 is different. By doing so, the wavelength of light emitted from the light-emitting layers 160 and 170 may be strengthened.

[0229] For example, the electrodes 101 to 104 are made of a conductive material having a function of reflecting light. When the refractive index is smaller than that of the light-emitting layer 160 or the light-emitting layer 170, the electrode The thickness of the conductive layer 101b of the electrode 101 is set so that the optical distance between the electrode 101 and the electrode 102 is m B λ B / 2(m B is a natural number, λ B represent the wavelengths of light to be intensified in region 222B, respectively) and Similarly, the thickness of the conductive layer 103b of the electrode 103 is adjusted to be equal to the thickness of the conductive layer 103b of the electrode 103. The optical distance between the electrode 102 is m G λ G / 2(m G is a natural number, λ G is strong in the area 222G The wavelength of the light emitted from the electrode 104 is adjusted to be 100 nm. The thickness of the electrode 104b is set such that the optical distance between the electrode 104 and the electrode 102 is m R λ R / 2(m R is self natural number, λ Rand represent the wavelengths of the light to be intensified in the region 222R).

[0230] As described above, a microcavity structure is provided, and the optical distance between a pair of electrodes in each region is adjusted. By adjusting the thickness, light scattering and absorption near each electrode are suppressed, resulting in high light extraction efficiency. In the above structure, the conductive layer 101b and the conductive layer 103 The conductive layer 104b preferably has a function of transmitting light. The materials constituting the conductive layers 103b, 104b may be the same as each other. The conductive layers 101b, 103b, and 104b may be different from each other. Each of these may have a structure in which two or more layers are laminated.

[0231] Since the light emitting element 252 shown in FIG. 5A is a top emission type light emitting element, the electrode 10 The conductive layer 101a of the electrode 101, the conductive layer 103a of the electrode 103, and the conductive layer 104 of the electrode 104 are The conductive layer 104a preferably has a function of reflecting light. It is preferable that the film has both a light transmitting function and a light reflecting function.

[0232] Furthermore, the light emitting element 254 shown in FIG. 5B is a bottom emission type light emitting element. The conductive layer 101a of the electrode 101, the conductive layer 103a of the electrode 103, and the conductive layer 104 of the electrode 104 are The conductive layer 104a preferably has a function of transmitting light and a function of reflecting light. In addition, the electrode 102 preferably has a function of reflecting light.

[0233] In the light-emitting element 252 and the light-emitting element 254, the conductive layer 101a and the conductive layer 103a The conductive layer 104a may be made of the same material or different materials. When the same material is used for the conductive layer 101a, the conductive layer 103a, and the conductive layer 104a, the light-emitting element 2 The manufacturing costs of the conductive layer 101a, the conductive layer 1052, and the light-emitting element 254 can be reduced. The conductive layer 3a and the conductive layer 104a may each have a structure in which two or more layers are stacked.

[0234] In addition, at least one of the light-emitting layers 160 and 170 may be formed by the method according to the second embodiment. It is preferable to use the benz[a]anthracene compound shown in The light emitted by the light-emitting layer has a region in which the proportion of delayed fluorescent components is 20% or more. In particular, in the region 222B, blue light having good luminous efficiency can be produced. The light-emitting element may have an emission spectrum peak in a certain color.

[0235] The light-emitting layer 160 and the light-emitting layer 170 are, for example, the light-emitting layer 170a and the light-emitting layer 170b. In this way, two layers can be laminated on each of the two light-emitting layers. The first compound and the second compound are two types of luminescent materials that have the function of exhibiting different colors. By using these layers, multiple lights can be emitted simultaneously. 70 and the luminescent material used in each luminescent layer is selected so that the luminescence exhibited by preferable.

[0236] The light-emitting layer 160 or the light-emitting layer 170 is configured to have three or more layers stacked. Alternatively, a layer that does not have a light-emitting material may be included.

[0237] As described above, at least one light-emitting layer contains the benzo[a]anthracene compound shown in the second embodiment. The light emitting element 252 or the light emitting element 254 having the light emitting layer is By using the organic EL element in the pixel, a display device with high light emission efficiency can be manufactured. A display device having the light element 252 or the light emitting element 254 can reduce power consumption. do.

[0238] Note that the structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. You can be there.

[0239] (Embodiment 5) In this embodiment, a configuration different from that shown in the first and fourth embodiments is The light emitting element and its light emitting mechanism will be described below with reference to FIGS. 6 and 7. cormorant.

[0240] <Configuration example 1 of light-emitting element> FIG. 6A is a schematic cross-sectional view of a light emitting element 450. FIG.

[0241] The light-emitting element 450 shown in FIG. 6A has a pair of electrodes (electrodes 401 and 402) between them. , a plurality of light-emitting units (in FIG. 6(A), light-emitting unit 441 and light-emitting unit 4 42). One light-emitting unit has an EL layer 100 shown in FIG. 1(A) or a That is, the light-emitting element 1 shown in FIG. 50, the light-emitting element 152 has one light-emitting unit, and the light-emitting element 450 has multiple light-emitting units. In the light-emitting element 450, the electrode 401 functions as an anode, and the electrode The following description will be given assuming that 402 functions as a cathode, but the configuration of the light emitting element 450 is as follows: The opposite is also fine.

[0242] In addition, in the light-emitting element 450 shown in FIG. 6A, the light-emitting unit 441 and the light-emitting unit The light-emitting units 441 and 442 are stacked, and a charge generating element is formed between the light-emitting units 441 and 442. The light emitting unit 441 and the light emitting unit 442 have the same configuration. For example, the light-emitting unit 441 may have the EL layer 10 shown in FIG. 0 or the EL layer 105 shown in FIG. 3 is used, and a phosphorescent material is used as the light-emitting material in the light-emitting unit 442. It is preferable to use a light-emitting layer having the following formula:

[0243] That is, the light-emitting element 450 includes a light-emitting layer 420 and a light-emitting layer 430. The optical unit 441 includes a hole injection layer 411, a hole transport layer 412, an electron The light-emitting unit 442 includes a light-emitting layer 413 and an electron-injecting layer 414. In addition to 30, a hole injection layer 416, a hole transport layer 417, an electron transport layer 418, and an electron injection layer It has 419.

[0244] The charge generation layer 445 includes a composite material of an organic compound and an acceptor substance. The composite material can be used for the hole-injection layer 111 described in Embodiment 1. The organic compounds may be aromatic amine compounds, carbazole compounds, aromatic Various compounds such as hydrocarbons and polymeric compounds (oligomers, dendrimers, polymers, etc.) As the organic compound, a compound having a hole mobility of 1×10 -6 cm 2 / It is preferable to use a material with a Vs or higher. However, it is preferable to use a material with a higher hole transporting property than an electron transporting property. Other materials may be used as long as they are organic compounds and acceptor materials. The composite material has excellent carrier injection and transport properties, allowing for low-voltage and low-current driving. As in the light-emitting unit 442, the anode side of the light-emitting unit When the surface is in contact with the charge generation layer 445, the charge generation layer 445 serves as a hole injection layer for the light-emitting unit. The light-emitting unit may also have a hole-injection layer or hole-transport layer. In this case, the hole transport layer may not be provided.

[0245] The charge generation layer 445 may be a layer containing a composite material of an organic compound and an acceptor substance. For example, the organic EL element may be formed as a laminated structure in which layers made of the organic EL element are combined. A layer including a composite material of a compound and an acceptor substance and a layer including a compound selected from electron donor substances. The compound may be formed by combining a layer containing the compound with a compound having a high electron transporting property. A layer containing a composite material of an organic compound and an acceptor substance and a layer containing a transparent conductive film are combined. It may be formed by combining the above.

[0246] The charge generating layer 445 sandwiched between the light emitting unit 441 and the light emitting unit 442 is When a voltage is applied between the electrode 401 and the electrode 402, electrons are injected into one of the light-emitting units, It is sufficient if the hole is injected into the other light-emitting unit. For example, in FIG. 6(A), When a voltage is applied so that the potential of electrode 401 is higher than the potential of electrode 402, The charge generating layer 445 injects electrons into the light emitting unit 441 and holes into the light emitting unit 442. Enter.

[0247] In addition, in FIG. 6(A), a light-emitting element having two light-emitting units has been described. However, it can also be applied to light-emitting devices in which three or more light-emitting units are stacked. As shown in the light-emitting element 450, a plurality of light-emitting units are disposed between a pair of electrodes, and a charge generating layer is formed. By separating the layers, high brightness light emission is possible while keeping the current density low. A light-emitting element with a long life and low power consumption can be realized. .

[0248] At least one of the units has an EL layer 100 or an EL By applying the configuration of the layer 105, a light-emitting element with high luminous efficiency can be provided. In particular, at least one light-emitting layer has a benzo[a]anthracene compound. This makes it possible to provide a light-emitting element with high luminous efficiency.

[0249] The light-emitting layer 420 includes a host material 421 and a guest material 422. The optical layer 430 includes a host material 431 and a guest material 432. 31 includes an organic compound 431_1 and an organic compound 431_2.

[0250] In this embodiment, the light-emitting layer 420 may be the light-emitting layer 130 shown in FIG. The light-emitting layer 420 has the same structure as the light-emitting layer 135 shown in FIG. The material 421 and the guest material 422 are the same as the host material 131 and the guest material 132 contained in the light-emitting layer 130. Alternatively, the light-emitting layer 420 may contain the host material 42 The host material 136 and the guest material 422 contained in the light-emitting layer 135 are The guest material 432 in the light-emitting layer 430 corresponds to a phosphorescent material 137. The electrode 401, the electrode 402, the hole injection layer 411, the hole injection layer 416, hole transport layer 412, hole transport layer 417, electron transport layer 413, electron transport layer 418, The electron-injection layer 414 and the electron-injection layer 419 are formed by the same method as those for the electrode 101 and the electrode 102 shown in Embodiment 1. 02, a hole injection layer 111, a hole transport layer 112, an electron transport layer 118, and an electron injection layer 119 Therefore, in this embodiment, detailed description thereof will be omitted. do.

[0251] <Light Emitting Mechanism of Light Emitting Layer 420> The light-emitting mechanism of the light-emitting layer 420 is the same as that of the light-emitting layer 130 shown in FIG. 1(A) or that of the light-emitting layer 130 shown in FIG. The light emitting mechanism is the same as that of the light emitting layer 135.

[0252] <Light Emitting Mechanism of the Light Emitting Layer 430> Next, the light emitting mechanism of the light emitting layer 430 will be described below.

[0253] The organic compound 431_1 and the organic compound 431_2 in the light-emitting layer 430 form an exciplex. Here, the organic compound 431_1 is used as a host material, and the organic compound 431_ 2 will be explained as an assist material.

[0254] In the light-emitting layer 430, an organic compound 431_1 and an organic compound 431_2 which form an exciplex are The combination with _2 may be any combination that can form an exciplex. It is more preferable that one of the materials is a material having hole transport properties and the other is a material having electron transport properties. preferable.

[0255] The organic compound 431_1, the organic compound 431_2, and the guest material in the light-emitting layer 430 The correlation between the energy levels of 432 and 432 is shown in Figure 6(B). The symbols and symbols are as follows: ·Host(431_1): Organic compound 431_1 (host material) ·Assist(431_2): Organic compound 431_2 (assist material) Guest (432): Guest material 432 (phosphorescent material) ·Exciplex: Excitation complex ·S PH : The lowest singlet excited state of organic compound 431_1 T PH : The lowest triplet excited state of organic compound 431_1 T PG : The lowest level of the triplet excited state of guest material 432 (phosphorescent material) ·S E : The lowest level of the singlet excited state of an exciplex T E : The lowest level of the triplet excited state of an exciplex

[0256] Singlet exciplex formed by organic compound 431_1 and organic compound 431_2 The lowest excited state (S E ) and the lowest triplet excited state of the exciplex (T E )and are adjacent to each other (see Route C in Figure 6(B)).

[0257] And the (S E ) and (T E ) and the guest material 432 (phosphorus The photoluminescence can be obtained by shifting the excited triplet state of the photosensitive material to the lowest level (Figure 6(B)Ro (see ute D).

[0258] The above-described processes of Route C and Route D are referred to as E in this specification. It is called xTET (Exciplex-Triplet Energy Transfer). It may be referred to as.

[0259] In addition, one of the organic compounds 431_1 and 431_2 is a hole and the other is an electron. The electrons are then taken in and, as they approach each other, they rapidly form an exciplex. When it reaches an excited state, it quickly interacts with another to form an exciplex. Most of the excitons in the light-emitting layer 430 exist as exciplexes. The band gap is smaller than that of both compound 431_1 and organic compound 431_2. Therefore, the driving voltage is increased by the formation of an exciplex from the recombination of a hole and an electron. You can reduce the pressure.

[0260] By configuring the light-emitting layer 430 as described above, the guest material 432 (phosphorescent material ) can be efficiently obtained.

[0261] The light emitted from the light-emitting layer 420 has a peak at a shorter wavelength than the light emitted from the light-emitting layer 430. It is preferable that the light-emitting element has a structure including a phosphorescent material that emits light of a short wavelength. Therefore, by using fluorescent light for short wavelengths, A light-emitting element with little deterioration in luminance can be provided.

[0262] Furthermore, by obtaining light of different wavelengths from the light-emitting layer 420 and the light-emitting layer 430, multicolor The light-emitting element may have different emission peaks in the emission spectrum. Since the emitted light is synthesized, the emission spectrum has at least two maxima. .

[0263] The above structure is also suitable for obtaining white light emission. By making the light from the two fluorescent materials complementary to each other, white light can be emitted.

[0264] In addition, one or both of the light-emitting layers 420 and 430 may have multiple layers with different emission wavelengths. By using multiple luminescent materials, it is possible to produce high color rendering of three primary colors or four or more luminescent colors. White light can also be obtained. In this case, either one of the light-emitting layer 420 and the light-emitting layer 430 Alternatively, both may be further divided into layers, and each divided layer may contain a different light-emitting material. You can do that too.

[0265] <Examples of materials that can be used for the light-emitting layer> Next, materials that can be used for the light-emitting layer 420 and the light-emitting layer 430 will be described below. do.

[0266] <Materials that can be used for the light-emitting layer 420> The light-emitting layer 420 can be made of any of the materials for the light-emitting layer 13 shown in Embodiment 1. 0, or the material that can be used for the light-emitting layer 135 described in Embodiment 4 may be used. .

[0267] <Materials that can be used for the light-emitting layer 430> In the light-emitting layer 430, the organic compound 431_1 (host material) is present in the largest amount by weight. The guest material 432 (phosphorescent material) is dispersed in the organic compound 431_1 (host material). do.

[0268] Organic compounds 431_1 (host materials) include zinc and aluminum metal complexes, Oxadiazole derivatives, triazole derivatives, benzimidazole derivatives, quinoxaline dibenzoquinoxaline derivatives, dibenzothiophene derivatives, dibenzofuran derivatives Conductors, pyrimidine derivatives, triazine derivatives, pyridine derivatives, bipyridine derivatives, phenanthroline derivatives, Other examples include aromatic amines and carbazole derivatives. Conductors and the like.

[0269] As the guest material 432 (phosphorescent material), iridium, rhodium, or platinum-based organic Metal complexes, or metal complexes, among which organic iridium complexes, e.g., iridium The orthometalated complex is preferably a 4H-triazole. Ligand, 1H-triazole ligand, imidazole ligand, pyridine ligand, pyrimidine The metal complexes include a pyrazine ligand, an isoquinoline ligand, and the like. Examples include platinum complexes having porphyrin ligands.

[0270] The organic compound 431_2 (assist material) is a compound of organic compound 431_1 and an exciplex. In this case, the emission peak of the exciplex is Triplet MLCT (Metal to Ligand Charge Tran) The absorption band of the sfer transition, more specifically, the absorption band on the longest wavelength side, is overlapped with the organic compound. Select a compound 431_1, an organic compound 431_2, and a guest material 432 (phosphorescent material). This makes it possible to obtain a light-emitting device with dramatically improved luminous efficiency. However, when a thermally activated delayed fluorescent material is used instead of a phosphorescent material, the longest wavelength The long absorption band is preferably a singlet absorption band.

[0271] The light-emitting material contained in the light-emitting layer 430 is a material capable of converting triplet excitation energy into light. The material capable of converting triplet excitation energy into luminescence is a phosphorescent material. In addition to this, thermally activated delayed fluorescence Therefore, phosphorescent materials are also known as The above-mentioned part may be read as a thermally activated delayed fluorescent material. Delayed fluorescent materials are materials that convert triplet excited states into singlet excited states with a small amount of thermal energy. It is possible to convert the electrons into electrons (reverse intersystem crossing) and efficiently emit light (fluorescence) from the singlet excited state. In addition, the conditions for efficiently obtaining thermally activated delayed fluorescence are three The energy difference between the doublet excited energy level and the singlet excited energy level is preferably 0 e V or more and 0.2 eV or less, more preferably 0 eV or more and 0.1 eV or less. The following are some of the reasons:

[0272] In addition, materials that exhibit thermally activated delayed fluorescence can be synthesized by themselves through reverse intersystem crossing from the triplet excited state. The material may be capable of generating a doublet excited state, or may be an exciplex (or It may also be a combination of two materials that form a composite (also called an exciplex).

[0273] In addition, the light-emitting material contained in the light-emitting layer 420 and the light-emitting material contained in the light-emitting layer 430 have different light-emitting colors. There is no limitation, and they may be the same or different. The light emitted from each is mixed and emitted outside the device. For example, if the colors of the two lights are complementary to each other, the light-emitting element will emit white light. In consideration of the reliability of the light-emitting element, the light-emitting layer 420 can emit light. The emission peak wavelength of the light-emitting material is preferably shorter than that of the light-emitting material contained in the light-emitting layer 430. Desirable.

[0274] <Configuration example 2 of light-emitting element> Next, regarding a configuration example different from that of the light-emitting element shown in FIG. 6, the following will be described with reference to FIGS. 7(A) and 7(B). Give an explanation.

[0275] FIG. 7A is a schematic cross-sectional view of the light emitting element 452. FIG.

[0276] The light-emitting element 452 shown in FIG. 7A has a pair of electrodes (electrodes 401 and 402) between them. The EL layer 400 is sandwiched between the electrodes 401 and 402. and electrode 402 functions as a cathode.

[0277] The EL layer 400 includes a light-emitting layer 420 and a light-emitting layer 430. In 452, the EL layer 400 includes a hole injection layer 420 and a light emitting layer 430. 411, hole transport layer 412, electron transport layer 418, and electron injection layer 419 are shown. However, these laminated structures are only examples, and the configuration of the EL layer 400 in the light-emitting element 452 is not limited to these. For example, the order in which the layers in the EL layer 400 are stacked may be changed. Alternatively, the EL layer 400 may be provided with a functional layer other than the above-mentioned layers. For example, the function of injecting carriers (electrons or holes), the function of transporting carriers, It is sufficient to have a configuration that has a function of suppressing carriers and a function of generating carriers.

[0278] The light-emitting layer 420 includes a host material 421 and a guest material 422. The optical layer 430 includes a host material 431 and a guest material 432. The host material 431 is The guest material 422 includes an organic compound 431_1 and an organic compound 431_2. The following description will be given assuming that the guest material 432 is a phosphorescent material.

[0279] <Light Emitting Mechanism of Light Emitting Layer 420> The light-emitting mechanism of the light-emitting layer 420 is the same as that of the light-emitting layer 130 shown in FIG. 1(A) or that of the light-emitting layer 130 shown in FIG. The light emitting mechanism is the same as that of the light emitting layer 135.

[0280] <Light Emitting Mechanism of the Light Emitting Layer 430> The light-emitting mechanism of the light-emitting layer 430 is the same as that of the light-emitting layer 430 shown in FIG. 6(A). be.

[0281] <Light Emission Mechanism of Light Emitting Layer 420 and Light Emitting Layer 430> The light-emitting mechanisms of the light-emitting layer 420 and the light-emitting layer 430 have already been described. As shown in element 452, light-emitting layer 420 and light-emitting layer 430 are in contact with each other. In this case, the host of the emitting layer 420 is converted from the exciplex at the interface between the emitting layer 420 and the emitting layer 430. Energy transfer to the material 421 (especially the triplet excited level) occurs. Even if the triplet excitation energy is not converted into light emission, the triplet excitation energy can be converted into light emission in the light-emitting layer 420.

[0282] The T1 level of the host material 421 of the light-emitting layer 420 is higher than that of the organic compound of the light-emitting layer 430. It is preferable that the T1 level of the light-emitting layer is lower than the T1 level of the organic compound 431_1 and the organic compound 431_2. In 420, the S1 level of the host material 421 is the S1 level of the guest material 422 (fluorescent material). The T1 level of the host material 421 is higher than the T1 level of the guest material 422 (fluorescent material). It is preferable that the level is lower than 1.

[0283] Specifically, when TTA is used for the light-emitting layer 420 and ExTET is used for the light-emitting layer 430, The correlation of the energy levels is shown in Figure 7(B). The notations and symbols in Figure 7(B) are as follows: It is as follows. Fluorescence EML(420): Fluorescent light-emitting layer (light-emitting layer 420) Phosphorescence EML(430): Phosphorescent light-emitting layer (light-emitting layer 430) ·S FH : The lowest singlet excited state of the host material 421 T FH : The lowest triplet excited state of the host material 421 ·S FG : The lowest level of the singlet excited state of guest material 422 (fluorescent material) T FG : The lowest level of the triplet excited state of guest material 422 (fluorescent material) ·S PH : The lowest singlet excited state of the host material (organic compound 431_1) T PH : The lowest triplet excited state of the host material (organic compound 431_1) T PG : The lowest level of the triplet excited state of guest material 432 (phosphorescent material) ·S E : The lowest level of the singlet excited state of an exciplex T E : The lowest level of the triplet excited state of an exciplex

[0284] As shown in Figure 7(B), exciplexes exist only in the excited state, so The exciton diffusion between the complexes is difficult. E , T E ) is the The excitation level (S PH , T PH ), so the energy diffusion from the exciplex to the organic compound 431_1 Similarly, energy diffusion from the exciplex to the organic compound 431_2 does not occur. That is, in the phosphorescent light-emitting layer (light-emitting layer 430), the exciton diffusion length of the exciplex is Since the time is short, it is possible to maintain the efficiency of the phosphorescent light-emitting layer (light-emitting layer 430). At the interface between the light-emitting layer (light-emitting layer 420) and the phosphorescent light-emitting layer (light-emitting layer 430), A part of the triplet excitation energy of the exciplex in the fluorescent light-emitting layer (light-emitting layer 420) is transferred to the fluorescent light-emitting layer (light-emitting layer 420). Even if they diffuse, the triplet excited electrons of the fluorescent-emitting layer (light-emitting layer 420) generated by the diffusion Since the energy is emitted through the TTA, it is possible to reduce energy loss. do.

[0285] As described above, the light-emitting device 452 uses ExTET for the light-emitting layer 430 and By using TTA in 20, energy loss is reduced, resulting in high luminous efficiency. As shown in the light-emitting element 452, the light-emitting layer 420 and the light-emitting layer 430 are in contact with each other, the energy loss is reduced and E It is possible to reduce the number of layers of the L layer 400. Therefore, the light emitting device can be manufactured at low cost. It can be said that:

[0286] The light-emitting layer 420 and the light-emitting layer 430 may not be in contact with each other. In this case, the organic compound 431_1, the organic compound 431_2, or The excited state of the guest material 432 (phosphorescent material) is converted into the host material 421 in the light-emitting layer 420. Energy transfer via the Dexter mechanism to the guest material 422 (fluorescent material) (especially triple Therefore, the energy transfer between the light-emitting layer 420 and the light-emitting layer 430 can be prevented. The layer provided on the substrate only needs to be several nanometers thick.

[0287] The layer provided between the light-emitting layer 420 and the light-emitting layer 430 may be made of a single material. The layer may contain a hole transporting material and an electron transporting material. A bipolar material may be used. Here, the bipolar material is a material that allows the movement of electrons and holes. The ratio of the hole transporting property to the electron transporting property is 100 or less. Alternatively, at least one of them may be the host material of the light-emitting layer 430. It may be formed of the same material as the organic compound 431_1 or the organic compound 431_2. This facilitates the fabrication of the light-emitting device and reduces the driving voltage. The transport material and the electron transport material may form an exciplex, which allows diffusion of excitons. Specifically, the host material (organic compound 43) of the light-emitting layer 430 can be effectively prevented. Excited states of 1_1 or organic compounds 431_2) or guest materials 432 (phosphorescent materials) The energy is transferred from the light emitting layer 420 to the host material 421 or the guest material 422 (fluorescent material). This can prevent energy transfer.

[0288] In the light emitting element 452, the recombination region of the carriers is formed with a certain degree of distribution. Therefore, it is preferable that the light-emitting layer 420 or the light-emitting layer 430 has an appropriate carrier. It is preferable that the guest material 432 (phosphorus) contained in the light-emitting layer 430 has an attrapping property. It is preferable that the gate insulating layer 420 has an electron trapping property. It is preferable that the layer material 422 (fluorescent material) has hole trapping properties.

[0289] The light emitted from the light-emitting layer 420 has a peak at a shorter wavelength than the light emitted from the light-emitting layer 430. It is preferable that the light-emitting element has a structure including a phosphorescent material that emits light of a short wavelength. Therefore, by using fluorescent light for short wavelengths, A light-emitting element with little deterioration in luminance can be provided.

[0290] Furthermore, by obtaining light of different wavelengths from the light-emitting layer 420 and the light-emitting layer 430, multicolor The light-emitting element may have different emission peaks in the emission spectrum. Since the emitted light is synthesized, the emission spectrum has at least two maxima. .

[0291] The above structure is also suitable for obtaining white light emission. By making the light from the two fluorescent materials complementary to each other, white light can be emitted.

[0292] In addition, by using a plurality of light-emitting materials with different emission wavelengths in the light-emitting layer 420, the three primary colors can be It is also possible to obtain white light with high color rendering, consisting of four or more luminescent colors. The optical layer 420 is further divided into layers, and each divided layer contains a different luminescent material. You can do that too.

[0293] <Materials that can be used for the light-emitting layer> Next, materials that can be used for the light-emitting layer 420 and the light-emitting layer 430 will be described below. do.

[0294] <Materials that can be used for the light-emitting layer 420> In the light-emitting layer 420, the host material 421 is present in the largest amount by weight, and the guest material 422 The fluorescent material is dispersed in the host material 421. The S1 level of the host material 421 is The S1 level of the host material 421 is higher than the S1 level of the fluorescent material 422. It is preferable that the T1 level is lower than the T1 level of the source material 422 (fluorescent material).

[0295] The host material 421 preferably comprises a benz[a]anthracene compound. By doing so, it is possible to fabricate a light-emitting device in which the proportion of delayed fluorescence in the light emission is high and the light-emitting efficiency is high. Specifically, the compounds described in Embodiment 1 or 2 can be mentioned. can be done.

[0296] <Materials that can be used for the light-emitting layer 430> In the light-emitting layer 430, a host material (organic compound 431_1 or organic compound 431_2 ) is present in the largest amount by weight, and guest material 432 (phosphorescent material) is present in the largest amount by weight by weight. The host material ( The T1 level of the organic compound 431_1 and the organic compound 431_2 is the guest It is preferably higher than the T1 level of the material 422 (fluorescent material).

[0297] Host material (organic compound 431_1 and organic compound 431_2), guest material 432 The phosphorescent material may be the organic compound 431_1 described in the light-emitting element 450 of FIG. 6, An organic compound 431_2 and a guest material 432 can be used.

[0298] The light-emitting layer 420 and the light-emitting layer 430 can be formed by a deposition method (including a vacuum deposition method), an ink-jet method, or the like. The layer can be formed by a printing method, a coating method, a gravure printing method, or the like.

[0299] Note that the structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. You can be there.

[0300] (Embodiment 6) In this embodiment, the benz[a]anthracene compound described in Embodiment 2 is used as an organic semiconductor. As the active layer of a vertical transistor (static induction transistor: SIT), a type of semiconductor device Examples of forms to be used are given below.

[0301] The structure of the element is as shown in FIG. 8, in which the benzo[a]anthracene compound described in the second embodiment is used. A thin film active layer 330 containing a cesium compound is attached to a source electrode 301 and a drain electrode 302. The gate electrode 303 is embedded in the active layer 330. is electrically connected to a means for applying a gate voltage, and the source electrode 301 and The source electrode and drain electrode 302 are connected to a means for controlling the voltage between the source electrode and the drain electrode. are electrically connected.

[0302] In such a device structure, when no voltage is applied to the gate electrode 303, When a voltage is applied between the source electrode and the drain electrode, current flows (the device is in the ON state). In this state, when a voltage is applied to the gate electrode 303, a depletion layer is generated around the gate electrode 303. As a result, the current stops flowing (the organic semiconductor element 30 is in the OFF state). 0 acts as a transistor.

[0303] In vertical transistors, similar to light-emitting devices, it is necessary to develop a material that has both carrier transport properties and good film quality. The active layer requires a material having a higher conductivity than the benz[a]anthracene compound described in the second embodiment. The product satisfies these conditions and can be used favorably.

[0304] Note that the structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. You can be there.

[0305] (Embodiment 7) In this embodiment, a display device including a light-emitting element of one embodiment of the present invention will be described with reference to FIG. The explanation will be given below.

[0306] Note that FIG. 9(A) is a block diagram illustrating a display device of one embodiment of the present invention, and FIG. 1B is a circuit diagram illustrating a pixel circuit included in a display device of one embodiment of the present invention.

[0307] <Explanation about the display device> The display device shown in FIG. 9A has a region having pixels of a display element (hereinafter referred to as a pixel portion 802). and a circuit section (hereinafter referred to as a circuit section) that is disposed outside the pixel section 802 and has a circuit for driving the pixel. a circuit having a function of protecting the element (hereinafter referred to as a protection circuit 806) ) and a terminal portion 807. Note that the protection circuit 806 may not be provided. Good too.

[0308] A part or the whole of the driver circuit portion 804 is formed on the same substrate as the pixel portion 802. This makes it possible to reduce the number of parts and terminals. When a part or all of the driving circuit is not formed on the same substrate as the pixel portion 802, A part or the whole of the path portion 804 is COG or TAB (Tape Automated Bearing). It can be implemented by

[0309] The pixel section 802 is arranged in X rows (X is a natural number of 2 or more) and Y columns (Y is a natural number of 2 or more). The display device has a circuit for driving a plurality of display elements (hereinafter referred to as pixel circuit 801), The path portion 804 is a circuit for outputting a signal (scanning signal) for selecting a pixel (hereinafter referred to as a scanning line driving circuit 804a), for supplying signals (data signals) for driving the display elements of the pixels. The signal line driver circuit 804b includes a driver circuit such as the circuit (hereinafter referred to as a signal line driver circuit 804b).

[0310] The scanning line driver circuit 804a includes a shift register and the like. A signal for driving the shift register is inputted through the terminal portion 807, and a signal is outputted. For example, a start pulse signal, a clock signal, etc. are input to the scanning line driver circuit 804a. The scanning line driving circuit 804a is connected to the wiring to which the scanning signal is applied (hereinafter referred to as the wiring). The scanning lines GL_1 to GL_X are connected to the gate electrodes GL_1 to GL_X. A plurality of driving circuits 804a are provided, and the scanning lines GL_1 to GL_3 are driven by the plurality of scanning line driving circuits 804a. Alternatively, the scanning line driving circuit 804a may control the GL_X by dividing it. However, the present invention is not limited to this, and the scanning line driving circuit 80 4a may also provide other signals.

[0311] The signal line driver circuit 804b includes a shift register and the like. Through the terminal portion 807, signals for driving the shift register as well as the source of the data signal are transmitted. The signal line driver circuit 804b receives the image signal and drives the pixel circuit The signal line driver circuit 804b has a function of generating a data signal to be written to the signal line driver circuit 801. A data signal is generated in accordance with a pulse signal obtained by inputting a start pulse, a clock signal, etc. The signal line driver circuit 804b has a function of controlling the output of a signal. The data lines DL_1 to DL_Y are connected to the data lines DL_2 through DL_Y. Alternatively, the signal line driver circuit 804b may have a function of supplying an initialization signal. However, the present invention is not limited to this, and the signal line driver circuit 804b may also supply other signals. It is possible.

[0312] The signal line driver circuit 804b is configured using, for example, a plurality of analog switches. The signal line driver circuit 804b sequentially turns on a plurality of analog switches, The image signal can be time-divided and output as a data signal. The signal line driver circuit 804b may be configured using the same.

[0313] Each of the plurality of pixel circuits 801 is connected to one of the plurality of scanning lines GL to which a scanning signal is applied. A pulse signal is input via the data line DL, and a data signal is given via one of the data lines DL. Each of the pixel circuits 801 receives a data signal via a scanning line driving circuit. 804a controls the writing and holding of data of the data signal. The second pixel circuit 801 is connected to the scanning line driving circuit GL_m (m is a natural number equal to or less than X) via the scanning line GL_m. A pulse signal is input from 804a, and the potential of the data line DL_n ( A data signal is input from the signal line driver circuit 804b via the signal line driver circuit 804b (n is a natural number equal to or less than Y).

[0314] The protection circuit 806 shown in FIG. 9A is, for example, a protection circuit including a scanning line driver circuit 804a and a pixel circuit 80 1. Alternatively, the protection circuit 806 is connected to the signal line driving circuit The protection circuit 804b is connected to the data line DL, which is the wiring between the protection circuit 804b and the pixel circuit 801. The circuit 806 can be connected to a wiring between the scanning line driver circuit 804a and the terminal portion 807. Alternatively, the protection circuit 806 may be formed on the wiring between the signal line driver circuit 804b and the terminal portion 807. The terminal portion 807 can be connected to the display device via a power supply and a control circuit. This refers to the part where terminals for inputting control signals and image signals are provided.

[0315] When a potential outside a certain range is applied to the wiring to which the protection circuit 806 is connected, the protection circuit 806 This is a circuit that brings one wire into electrical continuity with another wire.

[0316] As shown in FIG. 9A, a pixel section 802 and a driver circuit section 804 are provided with a protection circuit 806. By providing a This can improve the resistance of the display device to overcurrents caused by electrical discharges, etc. However, the configuration of the protection circuit 806 is not limited to this. For example, the protection circuit 806 may be provided in the scanning line driving circuit 804a. A configuration in which a protection circuit 806 is connected, or a configuration in which a protection circuit 806 is connected to a signal line driver circuit 804b Alternatively, a protection circuit 806 may be connected to the terminal portion 807. You can also do this.

[0317] In FIG. 9A, the scanning line driver circuit 804a and the signal line driver circuit 804b However, the present invention is not limited to this configuration. For example, only the scanning line driver circuit 804a is formed, and a separately prepared signal line driver circuit is formed. Mounting a substrate (for example, a drive circuit substrate formed of a single crystal semiconductor film or a polycrystalline semiconductor film) This may also be a configuration.

[0318] <Pixel circuit configuration example> The plurality of pixel circuits 801 shown in FIG. 9A may have the configuration shown in FIG. 9B, for example. can be done.

[0319] The pixel circuit 801 shown in FIG. 9B includes transistors 852 and 854 and a capacitor 862. and a light-emitting element 872.

[0320] One of the source electrode and the drain electrode of the transistor 852 is supplied with a data signal. The gate of the transistor 852 is electrically connected to the wiring (data line DL_n). The electrodes are electrically connected to wiring (scanning lines GL_m) to which gate signals are applied.

[0321] The transistor 852 has a function of controlling writing of data signals.

[0322] One of the pair of electrodes of the capacitor 862 is connected to a wiring to which a potential is applied (hereinafter, a potential supply line VL _a), and the other is electrically connected to the source electrode and drain electrode of transistor 852. The second electrode is electrically connected to the other of the first and second electrodes.

[0323] The capacitor 862 functions as a storage capacitor for holding written data.

[0324] One of the source electrode and the drain electrode of the transistor 854 is connected to the potential supply line VL_a. Furthermore, the gate electrode of transistor 854 is electrically connected to the It is electrically connected to the other of the source electrode and the drain electrode.

[0325] One of the anode and cathode of the light emitting element 872 is electrically connected to the potential supply line VL_b. The other is electrically connected to the other of the source electrode and drain electrode of the transistor 854. will be done.

[0326] The light-emitting element 872 may be any of the light-emitting elements described in any of Embodiments 1 to 5. can be done.

[0327] A high power supply potential VDD is applied to one of the potential supply lines VL_a and VL_b. and the other is supplied with a low power supply potential VSS.

[0328] In a display device having the pixel circuit 801 of FIG. 9B, for example, the scanning line The pixel circuits 801 in each row are selected in sequence by the driving circuit 804a, and the transistors 852 are turned on. The data signal is written in this state.

[0329] The pixel circuit 801 in which data has been written is turned off by turning off the transistor 852. Furthermore, the potential of the transistor 854 changes depending on the potential of the written data signal. The amount of current flowing between the source electrode and the drain electrode is controlled, and the light emitting element 872 The light is emitted at a brightness that corresponds to the flow rate. By repeating this process row by row, an image can be displayed.

[0330] Furthermore, the light-emitting element of one embodiment of the present invention may be an active matrix light-emitting element having an active element in a pixel of a display device. The display device is a passive matrix type that does not have active elements in the pixels. It can be applied to each method.

[0331] In the active matrix system, the active element (active element, nonlinear element) is a transistor. By using not only transistors but also various active elements (active elements, nonlinear elements), For example, MIM (Metal Insulator Metal) or T It is also possible to use FD (Thin Film Diode) and other elements. Since the number of manufacturing steps is small, it is possible to reduce manufacturing costs and improve yields. Alternatively, these elements can improve the aperture ratio due to their small size. This makes it possible to achieve low power consumption and high brightness.

[0332] Other than the active matrix type, active elements (active elements, nonlinear elements) It is also possible to use a passive matrix type that does not use active elements (active elements). Since it does not use any nonlinear elements, there are fewer manufacturing steps, which reduces manufacturing costs and improves yield. Alternatively, active elements (active elements, non-linear elements) can be used. Since the aperture ratio is not increased, it is possible to achieve low power consumption or high brightness. This can be done.

[0333] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. can be done.

[0334] (Embodiment 8) In this embodiment, a display device including a light-emitting element of one embodiment of the present invention and a display device An electronic device having an input device attached thereto will be described with reference to FIGS. 10 to 14. FIG.

[0335] <Touch panel explanation 1> In the present embodiment, an example of an electronic device is a device that combines a display device and an input device. The touch panel 2000 will be described. The case where the .

[0336] 10(A) and 10(B) are perspective views of the touch panel 2000. In B), representative components of touch panel 2000 are shown for clarity.

[0337] The touch panel 2000 includes a display device 2501 and a touch sensor 2595 (see FIG. 1 0(B)). The touch panel 2000 includes a substrate 2510, a substrate 2570, and a substrate The substrate 2510, the substrate 2570, and the substrate 2590 are all However, any one of the substrates 2510, 2570, and 2590 is flexible. Alternatively, one or all of the components may be configured to be non-flexible.

[0338] The display device 2501 has a plurality of pixels on a substrate 2510 and a display device that can supply signals to the pixels. The plurality of wirings 2511 are arranged around the periphery of the substrate 2510. The wire is routed through a cable, part of which forms the terminal 2519. The terminal 2519 is an FPC2509 (1) and electrically connect.

[0339] The substrate 2590 is electrically connected to the touch sensor 2595. The plurality of wirings 2598 are routed around the periphery of the substrate 2590. The terminal is electrically connected to the FPC2509(2). In FIG. 10(B), for clarity, the back side of the substrate 2590 (substrate 2510 The electrodes and wiring of the touch sensor 2595 provided on the surface opposite to the touch sensor 2595 are shown by solid lines. .

[0340] As the touch sensor 2595, for example, a capacitance type touch sensor can be applied. The capacitive type includes a surface type electrostatic capacitance type and a projected type electrostatic capacitance type.

[0341] The projected capacitive type is mainly divided into self-capacitance type and mutual capacitance type, which differ mainly in the driving method. The mutual capacitance method is preferable because it allows simultaneous multi-point detection.

[0342] The touch sensor 2595 shown in FIG. 10(B) is a projected capacitive touch sensor. This is a configuration in which the

[0343] The touch sensor 2595 can detect the proximity or contact of a detection object such as a finger. Various sensors can be applied.

[0344] The projected capacitive touch sensor 2595 has an electrode 2591 and an electrode 2592. The electrode 2591 is electrically connected to one of the plurality of wirings 2598, and the electrode 2592 is It is electrically connected to any other of the plurality of wirings 2598.

[0345] As shown in FIGS. 10(A) and 10(B), the electrodes 2592 are made of a plurality of electrodes repeatedly arranged in one direction. The shape is such that the quadrilaterals are connected at their corners.

[0346] The electrode 2591 is quadrilateral and is repeated in a direction intersecting the direction in which the electrode 2592 extends. are placed.

[0347] The wiring 2594 is electrically connected to the two electrodes 2591 that sandwich the electrode 2592. In this case, it is preferable that the area of ​​the intersection between the electrode 2592 and the wiring 2594 is as small as possible. This reduces the area where no electrodes are provided, reducing variations in transmittance. As a result, the variation in brightness of light passing through the touch sensor 2595 can be reduced. can be done.

[0348] The shapes of the electrodes 2591 and 2592 are not limited to this, and may take various shapes. For example, multiple electrodes 2591 are arranged with as few gaps as possible, and A plurality of electrodes 2592 are provided at intervals so that there is an area where they do not overlap with the electrodes 2591. In this case, a contact between two adjacent electrodes 2592 may be provided. Providing an insulated dummy electrode is preferable because it can reduce the area of ​​the region with different transmittance. .

[0349] <Explanation about the display device> Next, the display device 2501 will be described in detail with reference to FIG. ) corresponds to a cross-sectional view taken along the dashed dotted line X1-X2 shown in FIG. 10(B).

[0350] The display device 2501 has a plurality of pixels arranged in a matrix. and a pixel circuit for driving the display element.

[0351] In the following description, a light emitting element that emits white light is applied to a display element. However, the display element is not limited to this. For example, To achieve different colors, light emitting elements with different luminescent colors may be applied.

[0352] The substrate 2510 and the substrate 2570 may have a water vapor permeability of, for example, 1×10 -5 g· m -2 ·day -1 Less than 1 × 10 -6 g·m -2 ·day -1 It is possible that A flexible material can be preferably used. Alternatively, the thermal expansion coefficient of the substrate 2510 and the It is preferable to use a material whose coefficient of thermal expansion is approximately equal to that of the plate 2570. For example, is 1×10 -3 / K or less, preferably 5×10 -5 / K or less, more preferably 1×10 - 5 A material having a solubility of 0.1 kJ / K or less can be suitably used.

[0353] The substrate 2510 has an insulating layer 2510a that prevents impurities from diffusing into the light-emitting element, and a flexible The substrate 2510b and the adhesive layer 2 that bonds the insulating layer 2510a and the flexible substrate 2510b together. The substrate 2570 is a laminate having a layer 510c and a layer 510d. and a flexible substrate 2570b. 2570b and an adhesive layer 2570c that bonds them together.

[0354] The adhesive layer 2510c and the adhesive layer 2570c may be made of, for example, polyester or polyolefin. Polyimide, polycarbonate or acrylic Polyurethane resin, epoxy resin, or silicone resin can be used. Any material containing a resin having a siloxane bond can be used.

[0355] In addition, a sealing layer 2560 is provided between the substrate 2510 and the substrate 2570. It is preferable that the refractive index of the sealing material is larger than that of air. When light is extracted from the layer 2560 side, the sealing layer 2560 can also serve as an optical bonding layer. Cut.

[0356] A sealant may be formed on the outer periphery of the sealing layer 2560. As a result, the area surrounded by the substrate 2510, the substrate 2570, the sealing layer 2560, and the sealant The sealing layer 2560 may have a light emitting element 2550R. An inert gas (nitrogen, argon, etc.) may be filled. In addition, a desiccant may be added to the inert gas. It is also possible to provide a structure in which moisture and the like are absorbed by the resin. It may be filled with a resin, such as a PVC (polyvinyl chloride) resin or an acrylic resin. , polyimide resin, epoxy resin, silicone resin, PVB (polyvinyl butyral )-based resin or EVA (ethylene vinyl acetate)-based resin can be used. As the sealing material, it is preferable to use, for example, an epoxy resin or glass frit. It is also preferable to use a material that is impermeable to moisture and oxygen as the sealing material. It is suitable.

[0357] The display device 2501 also has a pixel 2502R. The pixel 2502R is a light-emitting model. It has a Joule 2580R.

[0358] The pixel 2502R includes a light emitting element 2550R and a power supply for the light emitting element 2550R. The transistor 2502t is a transistor that can The light emitting module 2580R includes a light emitting element 2550R and It has a colored layer 2567R.

[0359] The light emitting element 2550R includes a lower electrode, an upper electrode, and an EL layer between the lower electrode and the upper electrode. The light-emitting element 2550R may be, for example, any of the light-emitting elements described in Embodiments 1 to 5. Optical elements can be applied.

[0360] In addition, a microcavity structure is adopted between the lower electrode and the upper electrode, and at a specific wavelength, The light intensity may be increased.

[0361] Furthermore, when the sealing layer 2560 is provided on the side from which light is extracted, the sealing layer 2560 It contacts the optical element 2550R and the colored layer 2567R.

[0362] The colored layer 2567R is located so as to overlap the light emitting element 2550R. A part of the light emitted by 2550R passes through the colored layer 2567R and is emitted in the direction of the arrow shown in the figure. The light is emitted to the outside of the optical module 2580R.

[0363] Furthermore, the display device 2501 is provided with a light-shielding layer 2567BM in the light-emitting direction. The light-shielding layer 2567BM is provided so as to surround the colored layer 2567R.

[0364] The colored layer 2567R only needs to have a function of transmitting light in a specific wavelength band. For example, a color filter that transmits light in the red wavelength band, a color filter that transmits light in the green wavelength band, A color filter that transmits light in the blue wavelength band, and a color filter that transmits light in the yellow wavelength band. A transparent color filter can be used. Each color filter is made of various materials. The method includes printing, inkjet printing, and etching using photolithography technology. It can be formed by.

[0365] The display device 2501 is also provided with an insulating layer 2521. The insulating layer 2521 is formed to flatten the unevenness caused by the pixel circuit. In addition, the insulating layer 2521 has a function of suppressing diffusion of impurities. This prevents the reliability of the transistor 2502t and the like from being reduced due to the diffusion of impurities. It can be suppressed.

[0366] The light emitting element 2550R is formed above the insulating layer 2521. The lower electrode of 550R is provided with a partition wall 2528 that overlaps the edge of the lower electrode. A spacer for controlling the distance between the substrate 2510 and the substrate 2570 is provided on the partition wall 2528. It may be formed.

[0367] The scanning line driver circuit 2503g(1) includes a transistor 2503t and a capacitor 2503c. The driver circuit and the pixel circuit can be formed on the same substrate in the same process. do.

[0368] Moreover, wiring 2511 capable of supplying signals is provided on the substrate 2510 . A terminal 2519 is provided on the wiring 2511. The terminal 2519 is also provided with an FP C2509(1) is electrically connected. FPC2509(1) also transmits video signals, It has the function of supplying clock signals, start signals, reset signals, etc. 509(1) includes a printed wiring board (PWB) d) may be attached.

[0369] In addition, transistors with various structures can be applied to the display device 2501. In 11(A), a case where a bottom gate type transistor is applied is illustrated. However, the present invention is not limited to this, and for example, a top gate type transistor shown in FIG. The display device 2501 may be configured to use the same.

[0370] In addition, there is no particular limitation on the polarity of the transistor 2502t and the transistor 2503t. There is no fixed definition, and the structure has N-channel and P-channel transistors. A structure consisting of either a P-channel transistor or a P-channel transistor is used. In addition, the crystal structure of the semiconductor film used in the transistors 2502t and 2503t may be For example, an amorphous semiconductor film or a crystalline semiconductor film can be used. In addition, the semiconductor material may be a group 13 semiconductor (e.g., a semiconductor containing gallium). ), group 14 semiconductors (e.g., semiconductors containing silicon), compound semiconductors (oxide semiconductors The transistor 2502t and the transistor 2503t, or both of them have an energy gap of 2 eV or more, preferably By using an oxide semiconductor with a conductivity of 2.5 eV or more, more preferably 3 eV or more, The oxide semiconductor is preferably In, because it can reduce the off-state current of the semiconductor. -Ga oxide, In-M-Zn oxide (M is aluminum (Al) or gallium (Ga)) , yttrium (Y), zirconium (Zr), lanthanum (La), cerium (Ce), Examples include tin (Sn), hafnium (Hf), or neodymium (Nd).

[0371] <Explanation about touch sensors> Next, the touch sensor 2595 will be described in detail with reference to FIG. (C) corresponds to a cross-sectional view taken along the dashed dotted line X3-X4 shown in FIG. 10(B).

[0372] The touch sensor 2595 is made up of electrodes 2591 and electrodes 2592 arranged in a staggered pattern on a substrate 2590. 2592, an insulating layer 2593 covering the electrodes 2591 and 2592, and the adjacent electrodes 25 91 and a wiring 2594 that electrically connects them.

[0373] The electrode 2591 and the electrode 2592 are formed using a light-transmitting conductive material. Examples of conductive materials having the formula include indium oxide, indium tin oxide, and indium zinc oxide. Conductive oxides such as zinc oxide, zinc oxide, and zinc oxide doped with gallium can be used. A film containing graphene may also be used. The film containing graphene may be, for example, a film-like The graphene oxide film can be formed by reducing the graphene oxide film formed on the substrate. For example, a method of applying heat can be mentioned.

[0374] For example, a film of a light-transmitting conductive material is formed on the substrate 2590 by sputtering. After that, various patterning techniques such as photolithography are used to remove unnecessary parts. , an electrode 2591 and an electrode 2592 can be formed.

[0375] The insulating layer 2593 may be made of a resin such as acrylic or epoxy. In addition to resins with siloxane bonds, silicon oxide, silicon oxynitride, aluminum oxide, Inorganic insulating materials such as rubber can also be used.

[0376] An opening reaching the electrode 2591 is provided in the insulating layer 2593, and a wiring 2594 is adjacent to the opening. The transparent conductive material is used to increase the aperture ratio of the touch panel. Therefore, it can be suitably used for the wiring 2594. A material having higher conductivity than the electrode 2592 is preferable for the wiring 2594 because it can reduce electrical resistance. It can be used appropriately.

[0377] The electrodes 2592 extend in one direction, and a plurality of electrodes 2592 are provided in a stripe pattern. Moreover, the wiring 2594 is provided so as to intersect with the electrode 2592.

[0378] A pair of electrodes 2591 is provided with one electrode 2592 sandwiched therebetween. A pair of electrodes 2591 are electrically connected.

[0379] The plurality of electrodes 2591 are arranged in a direction that is not necessarily perpendicular to one electrode 2592. The angle does not have to be 0 degrees, and may be greater than 0 degrees and less than 90 degrees.

[0380] The wiring 2598 is electrically connected to the electrode 2591 or the electrode 2592. A part of the wiring 2598 functions as a terminal. The wiring 2598 is made of, for example, aluminum. Aluminum, gold, platinum, silver, nickel, titanium, tungsten, chromium, molybdenum, iron, Use of metal materials such as ballast, copper, or palladium, or alloy materials containing such metal materials. can be done.

[0381] An insulating layer covering the insulating layer 2593 and the wiring 2594 is provided, and the touch sensor 2595 may be protected.

[0382] The connection layer 2599 electrically connects the wiring 2598 and the FPC 2509(2). .

[0383] The connection layer 2599 is made of an anisotropic conductive film (ACF). conductive film) and anisotropic conductive paste (ACP) Conductive Paste) can be used.

[0384] <Touch panel explanation 2> Next, the touch panel 2000 will be described in detail with reference to FIG. 10A corresponds to a cross-sectional view taken along the dashed line X5-X6 shown in FIG.

[0385] The touch panel 2000 shown in FIG. 12A is the same as the display device 250 described in FIG. 1 and the touch sensor 2595 described in FIG. 11(C) are bonded together.

[0386] The touch panel 2000 shown in FIG. 12(A) is similar to the touch panel 2000 shown in FIG. 11(A) and FIG. 11(C). In addition to the components described above, it has an adhesive layer 2597 and an anti-reflection layer 2567p.

[0387] The adhesive layer 2597 is provided in contact with the wiring 2594. The substrate 2590 is attached to the substrate 2570 so that the sensor 2595 overlaps the display device 2501. The adhesive layer 2597 is preferably transparent. The material 597 can be a thermosetting resin or an ultraviolet curing resin. For example, Acrylic resin, urethane resin, epoxy resin, or siloxane resin may be used. This can be done.

[0388] The anti-reflection layer 2567p is provided at a position overlapping the pixel. For example, a circular polarizing plate can be used.

[0389] Next, for a touch panel having a different configuration from that shown in FIG. 12(A), FIG. 12(B) This will be used to explain.

[0390] FIG. 12(B) is a cross-sectional view of the touch panel 2001. The panel 2001 is a touch panel 2000 shown in FIG. 12(A) and a display device 2501. The location of the touch sensor 2595 is different. Here, the different configurations are explained in detail. The description of the touch panel 2000 is cited for the parts where a similar configuration can be used.

[0391] The colored layer 2567R is located so as to overlap the light emitting element 2550R. The light-emitting element 2550R emits light toward the side where the transistor 2502t is provided. As a result, a part of the light emitted by the light emitting element 2550R passes through the colored layer 2567R, The light is emitted to the outside of light emitting module 2580R in the direction of the arrow shown in the figure.

[0392] The touch sensor 2595 is provided on the substrate 2510 side of the display device 2501. .

[0393] The adhesive layer 2597 is between the substrate 2510 and the substrate 2590 and is in contact with the display device 2501. Stick the Chisensor 2595 together.

[0394] As shown in FIGS. 12(A) and 12(B), the light emitted from the light emitting element is incident on the upper and lower surfaces of the substrate. The injection may be performed in either one or both directions.

[0395] <Explanation of how to drive the touch panel> Next, an example of a method for driving a touch panel will be described with reference to FIG.

[0396] FIG. 13A is a block diagram showing the configuration of a mutual capacitance type touch sensor. In (A), a pulse voltage output circuit 2601 and a current detection circuit 2602 are shown. In FIG. 13(A), the electrodes 2621 to which the pulse voltage is applied are designated as X1-X6, and the change in current The electrodes 2622 for detecting the change are shown as Y1-Y6, each with six wires. In addition, FIG. 13A shows a capacitance formed by overlapping an electrode 2621 and an electrode 2622. 2603. The electrodes 2621 and 2622 are interchangeable in function. It may be possible.

[0397] The pulse voltage output circuit 2601 is a circuit for applying pulses to the X1-X6 wirings in sequence. When a pulse voltage is applied to the wiring of X1-X6, the voltage that forms the capacitance 2603 An electric field is generated between the electrodes 2621 and 2622. The electric field generated between the electrodes is By using the change in the mutual capacitance of the capacitance 2603, the proximity of the object to be detected or A contact can be detected.

[0398] The current detection circuit 2602 detects the change in the mutual capacitance of the capacitor 2603 between the wires Y1 and Y6. This is a circuit for detecting changes in current. The wiring of Y1-Y6 detects the proximity of the object to be detected, Or, if there is no contact, the detected current value will not change, but the proximity of the object to be detected, or When the mutual capacitance decreases due to contact, a decrease in the current value is detected. The detection may be performed using an integrating circuit or the like.

[0399] Next, FIG. 13(B) shows the input voltage of the mutual capacitance type touch sensor shown in FIG. 13(A). The timing chart of the output waveform is shown in FIG. 13(B). In addition, in FIG. 13(B), when the object to be detected is not detected, Two cases are shown: when an object is detected (touched) and when an object is not detected (touched). For the wires Y1-Y6, the waveforms are shown as voltage values ​​corresponding to the detected current values. are.

[0400] A pulse voltage is applied to the wires X1-X6 in order, and the The waveform in the Y6 wiring changes. When there is no proximity or contact of the object to be detected, X1-X6 The waveforms of Y1-Y6 change uniformly according to the change in the voltage of the wiring. Or, at the contact point, the current value decreases, and the corresponding voltage waveform also changes. do.

[0401] In this way, by detecting the change in mutual capacitance, the proximity or contact of the object to be detected can be detected. It is possible.

[0402] <Sensor circuit explanation> In addition, in FIG. 13A, only a capacitor 2603 is provided at the intersection of the wiring as a touch sensor. The configuration of a passive matrix touch sensor is shown, but it has a transistor and a capacitor. An active matrix touch sensor may be used. An example of a sensor circuit included in the sensor is shown in FIG.

[0403] The sensor circuit shown in FIG. 14 includes a capacitor 2603, a transistor 2611, and a transistor 2612 and a transistor 2613.

[0404] A signal G2 is applied to the gate of the transistor 2613, and a signal G3 is applied to either the source or the drain of the transistor 2613. A voltage VRES is applied, and the other is connected to one electrode of the capacitor 2603 and the transistor 2611 The transistor 2611 has a source and a drain electrically connected to the gate of the transistor 2611. The source or drain of the transistor 2612 is electrically connected to the voltage VS The transistor 2612 receives a signal G1 at its gate and a signal S at its source or The other electrode of the drain is electrically connected to the wiring ML. The other electrode of the capacitor 2603 is connected to a voltage VS S is given.

[0405] Next, the operation of the sensor circuit shown in Fig. 14 will be described. First, the signal G2 is When a potential is applied to turn on the transistor 2613, the gate of the transistor 2611 is turned on. A potential corresponding to the voltage VRES is applied to the node n to which the signal G2 is connected. When a potential that turns off the transistor 2613 is applied, the potential of the node n Retained.

[0406] Next, the mutual capacitance of the capacitor 2603 changes when a detection object such as a finger approaches or touches the sensor. As a result, the potential of the node n changes from VRES.

[0407] The read operation applies a potential to the signal G1 that turns on the transistor 2612. The current flowing through the transistor 2611 in accordance with the potential of the node n, that is, the current flowing through the wiring ML By detecting this current, the proximity or contact of the object to be detected can be detected. This can be done.

[0408] The transistors 2611, 2612, and 2613 include: It is preferable to use an oxide semiconductor layer as the semiconductor layer in which the channel region is formed. By applying such a transistor to the transistor 2613, the potential of the node n This allows the voltage to be held for a long period of time, and the operation of re-supplying VRES to node n (restart) is performed. This can reduce the frequency of refresh operations.

[0409] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. can be done.

[0410] (Embodiment 9) In this embodiment, a display module and an electronic device including a light-emitting element of one embodiment of the present invention will be described. This will be explained with reference to FIGS. 15 and 16.

[0411] <Explanation about the display module> The display module 8000 shown in FIG. 15 includes an upper cover 8001 and a lower cover 8002. Between them, the touch sensor 8004 connected to FPC8003 and the touch sensor 8005 connected to FPC8006 are A display device 8006, a frame 8009, a printed circuit board 8010, and a battery 8011 are included. do.

[0412] The light-emitting element of one embodiment of the present invention can be used for the display device 8006, for example.

[0413] The upper cover 8001 and the lower cover 8002 are connected to the touch sensor 8004 and the display device 8005. The shape and dimensions can be changed appropriately to match the size of 006.

[0414] The touch sensor 8004 is a resistive or capacitive touch sensor mounted on the display device 8 8006. In addition, the opposing substrate (sealing substrate) of the display device 8006 It is also possible to provide a touch sensor function to the display device 8006. It is also possible to provide an optical sensor in each pixel to form an optical touch sensor.

[0415] The frame 8009 has a function of protecting the display device 8006 and also a function of preventing the operation of the printed circuit board 8010. It also functions as an electromagnetic shield to block electromagnetic waves generated by the frame. The frame 8009 may also function as a heat sink.

[0416] The printed circuit board 8010 includes a power supply circuit, a signal circuit for outputting a video signal and a clock signal. The power supply circuit is provided with a signal processing circuit. Alternatively, the power source may be a battery 8011 provided separately. This can be omitted if a commercial power source is used.

[0417] In addition, the display module 8000 includes components such as a polarizing plate, a retardation plate, and a prism sheet. It may also be provided in addition.

[0418] <Electronic device instructions> 16(A) to 16(G) are diagrams showing electronic devices. These electronic devices are A body 9000, a display unit 9001, a speaker 9003, operation keys 9005 (power switch, includes an operation switch), a connection terminal 9006, a sensor 9007 (force, displacement, position, speed, Acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electricity Measures field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared It may have a microphone 9008, etc.

[0419] The electronic devices shown in FIGS. 16A to 16G can have various functions. For example, functions to display various information (still images, videos, text images, etc.) on the display, Sensor function, calendar, date or time display function, various software ( It has the function of controlling processing by using a program, wireless communication function, and various functions using wireless communication function. Functions for connecting to computer networks, transmitting various data using wireless communication functions, or receiving the program or data recorded on the recording medium, and It is to be noted that the functions shown in FIGS. 16(A) to 16(G) can be implemented. The functions that the electronic device shown in the figure can have are not limited to these, and it may have various functions. Although not shown in FIGS. 16(A) to 16(G), the electronic device may include: The electronic device may have a plurality of display units. The function to take pictures, take videos, and save the images to a recording medium (external or built-in to the camera) ) and a function to display the captured image on the display unit.

[0420] The electronic devices shown in FIGS. 16A to 16G will be described in detail below.

[0421] FIG. 16A is a perspective view showing a mobile information terminal 9100. The display portion 9001 is flexible. The display unit 9001 can be incorporated along the screen. It is equipped with a touch panel, and can be operated by touching the screen with a finger or a stylus. By touching the icon displayed on the display 9001, the application can be started. can.

[0422] 16B is a perspective view showing a portable information terminal 9101. The portable information terminal 9101 is For example, the device has one or more functions selected from a telephone, a notebook, an information viewing device, etc. Specifically, it can be used as a smartphone. Although the speaker 9003, the connection terminal 9006, the sensor 9007, etc. are omitted in the illustration, It can be installed in the same position as the mobile information terminal 9100 shown in FIG. The information terminal 9101 can display text and image information on multiple surfaces. For example, Three operation buttons 9050 (also called operation icons or simply icons) are displayed on the display unit 900. 9051 shown in a dashed rectangle can be displayed on one side of the display unit 90. 01. An example of the information 9051 is an e-mail A display that notifies you of incoming calls, SNS (social networking services), etc. , subject of email or SNS, sender name of email or SNS, date and time, time, The remaining battery level, antenna reception strength, etc. Or, information 9051 is displayed. In place of the information 9051, an operation button 9050 or the like may be displayed.

[0423] 16(C) is a perspective view showing a portable information terminal 9102. The portable information terminal 9102 is , and has the function of displaying information on three or more surfaces of the display unit 9001. An example is shown in which information 9053 and information 9054 are displayed on different sides. The user of the portable information terminal 9102 stores the portable information terminal 9102 in the breast pocket of his / her clothes. In this state, the display (information 9053 in this case) can be confirmed. The telephone number or name of the caller is displayed in a position that can be observed from above the mobile information terminal 9102. The user can view the display without taking the mobile information terminal 9102 out of his pocket. You can check the call and decide whether to accept it or not.

[0424] 16(D) is a perspective view showing a wristwatch-type portable information terminal 9200. The 9200 is suitable for mobile phone calls, e-mail, document browsing and writing, music playback, and internet communications. It is possible to run various applications such as computer games. The display surface of the display unit 9001 is curved, and the display is performed along the curved display surface. In addition, the portable information terminal 9200 can perform short-distance wireless communication according to a communication standard. For example, by communicating with a wireless headset, handset The mobile information terminal 9200 also has a connection terminal 9006. It has a connector and can directly exchange data with other information terminals. Charging can also be performed via the connection terminal 9006. It may also be possible to supply power wirelessly without going through 6.

[0425] 16(E), (F), and (G) are perspective views showing a foldable portable information terminal 9201. 16(E) is a perspective view of the portable information terminal 9201 in an unfolded state, and FIG. (F) shows the mobile information terminal 9201 being changed from one of the unfolded state and the folded state to the other. 16(G) is a perspective view of the portable information terminal 9201 in a folded state. The portable information terminal 9201 is highly portable when folded, and is easily portable when unfolded. When the display is turned on, the seamless, wide display area provides excellent visibility of the display. The display unit 9001 of the display device 01 is made up of three housings 9000 connected by hinges 9055. The two housings 9000 are supported by the hinge 9055. This allows the portable information terminal 9201 to be reversibly transformed from an unfolded state to a folded state. For example, the portable information terminal 9201 can be bent with a radius of curvature of 1 mm or more and 150 mm or less. It can be done.

[0426] The electronic device described in this embodiment has a display unit for displaying some information. However, the light-emitting element of one embodiment of the present invention is not limited to an electronic device that does not have a display portion. In addition, the present invention can be applied to the display unit of the electronic device described in this embodiment. In the case of a display device, it is possible to provide a display along a curved display surface, or a display device that can be folded. Although the configuration of the display unit is exemplified as being foldable, the present invention is not limited to this. The display may be displayed on the display unit.

[0427] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. can be done.

[0428] (Embodiment 10) In this embodiment, an example of a lighting device to which a light-emitting element according to one embodiment of the present invention is applied will be described. This will be explained using FIG.

[0429] FIG. 17 shows an example in which the light-emitting element is used as an indoor lighting device 8501. Since the surface area can be increased, a large-area lighting device can be formed. By using a housing having the above structure, a lighting device 8502 having a curved light-emitting area can be formed. The light-emitting element shown in this embodiment mode has a thin film shape, and the housing can be designed with a high degree of freedom. Therefore, it is possible to create lighting devices with various elaborate designs. A large lighting device 8503 may be provided on the wall. A touch sensor may be provided in 503 to turn the power on or off.

[0430] In addition, by using light-emitting elements on the surface of the table, it has the function of a table. The lighting device 8504 can be used as a lighting device. This allows the lighting device to function as furniture.

[0431] As described above, various lighting devices using light-emitting elements can be obtained. This device is included in one aspect of the present invention.

[0432] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. You can be there. [Example]

[0433] In this example, the benzo[a]antagonism represented by the general formula (G1) described in Embodiment 2 was One of the helical compounds, 9-[4-(7-benzo[a]anthracene)phenyl]- The synthesis method of 9H-carbazole (abbreviation: 7CzPaBA, structural formula (100)) is detailed below. Explain in detail.

[0434] <Synthesis of 7CzPaBA> 7-Bromobenzo[a]anthracene 3.0 g (9.7 mmol), 4-(9H-cal (bazol-9-yl)phenylboronic acid 4.4 g (15.4 mmol) and sodium carbonate Place 1.1 g (10.5 mmol) in a 200 mL three-neck flask and replace the atmosphere in the flask with nitrogen. To this mixture was added 35.0 mL of toluene, 12.5 mL of ethanol, and 9.7 mL of water. The mixture was degassed by stirring while reducing the pressure inside the flask. 0.1 g (0.1 mmol) of (triphenylphosphine)palladium was added, and the mixture was The temperature was raised to 90°C and the mixture was stirred for 3.0 hours. After stirring, the mixture was suction filtered and separated into a cake and a filtrate. The residue was dissolved in toluene and passed through Florisil, Celite, and alumina. The filtrate was concentrated to obtain a solid. The solid was washed with toluene. The reaction scheme is shown below.

[0435] [ka]

[0436] The resulting solid (1.8 g) was purified by train sublimation. The conditions were a pressure of 3.2 Pa, argon gas flow rate of 5.0 mL / min, and 24 The solid was heated at 0° C. After purification by sublimation, 1.7 g of the desired solid was obtained with a recovery rate of 94%.

[0437] Nuclear magnetic resonance method ( 1 1 H NMR revealed that this compound was the target compound, 7CzPaBA. It was confirmed that the obtained substance 1 The H NMR data are shown below. of material 1 The 1 H NMR charts are shown in Figures 18(A) and 18(B).

[0438] 1 H NMR (CDCl3,300MHz): δ=7.36(ddd, J=7.7, 7 .7, 0.9Hz, 2H), 7.49-7.88(m, 16H), 8.20-8.24( m, 3H), 8.94(d, J=7.8Hz, 1H), 9.33(s, 1H).

[0439] <Characteristics of 7CzPaBA> Thermogravimetry-differential thermal analysis (TG-DTA) of the obtained 7CzPaBA avimetry-Differential Thermal Analysis) The measurements were carried out using a high-vacuum differential thermobalance (manufactured by Bruker AXS Co., Ltd., T The temperature was raised at normal pressure at a rate of 10°C / min under a nitrogen gas flow (flow rate 200mL / min), the relationship between weight and temperature (thermogravimetry) The 5% weight loss temperature was 369°C, indicating good heat resistance.

[0440] Next, the absorption spectrum and emission spectrum of 7CzPaBA in toluene solution are shown in Figure 19. (A)(B) Absorption and emission spectra of 7CzPaBA in a thin film state. 0(A)(B).

[0441] The absorption spectrum was measured using a UV-visible spectrophotometer (JASCO Corporation, V550 model). The absorption spectrum of 7CzPaBA in toluene solution was The absorption spectrum of the fluorine solution measured using a quartz cell was The absorption spectrum after subtracting the absorption spectrum of toluene is shown. Kuttor prepared a sample by depositing 7CzPaBA onto a quartz substrate and measured the absorption of this sample. The absorption spectrum is shown after subtracting the absorption spectrum of quartz from the emission spectrum. The PL-EL measurement device (Hamamatsu Photonics) was used to measure the capacitance. The emission spectrum of 7CzPaBA was measured by placing a toluene solution of 7CzPaBA in a quartz cell. The emission spectrum of the thin film was measured by evaporating 7CzPaBA onto a quartz substrate. The samples were prepared and measured. The film was fabricated by vacuum deposition on a quartz substrate. Ta.

[0442] As a result, the maximum absorption wavelength of 7CzPaBA in toluene solution was found to be around 392 nm. The maximum emission wavelength is around 396nm, 370nm, 355nm, and 341nm. It was found that the wavelengths were around 418 nm (excitation wavelength 342 nm) and around 418 nm. The maximum absorption wavelengths are around 395 nm, 376 nm, 360 nm, and 345 nm. The maximum emission wavelength is around 429 nm (excitation wavelength It was found to be at 378 nm.

[0443] In addition, the ionization potential of the thin film 7CzPaBA was measured in air using a photoelectron spectrometer. The ionization potential values ​​obtained were measured using a Riken Keiki AC-3. As a result of conversion, the HOMO level of 7CzPaBA was found to be -6.02 eV. ) from the absorption spectrum data of the thin film, it was calculated from the Tauc plot assuming direct transition. The absorption edge of 7CzPaBA was 2.98 eV. The optical energy gap of this is estimated to be 2.98 eV, and the HOMO level obtained previously is From the energy gap value of 7CzPaBA, the lowest unoccupied molecular orbital (Lowest Unoccupied Molecular Orbital) The LUMO (also called the LUMO) level is -3. 04 eV. Thus, 7CzPaBA exhibits a 2. It was found to have a wide energy gap of 98 eV. [Example]

[0444] In this example, the delayed fluorescence component due to TTA among the luminescent components according to one embodiment of the present invention is The light-emitting elements with a high proportion will be described in detail with reference to FIGS.

[0445] In this embodiment, a light-emitting element (light-emitting element 1, light-emitting element 2) corresponding to the light-emitting element 150 shown in FIG. Light-emitting element 2) and comparative light-emitting elements (comparative light-emitting element 1 and comparative light-emitting element 2) were fabricated. The fluorescence lifetime and light-emitting characteristics of the light-emitting device were measured.

[0446] The structures and abbreviations of the compounds used are shown below.

[0447] [ka]

[0448] <Fabrication of light-emitting element> <Fabrication of Light-Emitting Element 1> An indium tin oxide (ITSO) film containing silicon oxide was formed on the substrate as an electrode 101. The electrode 101 was formed to a thickness of 110 nm. m 2 (2mm x 2mm).

[0449] Next, the EL layer 100 was formed on the electrode 101. The hole injection layer 111 was formed of 3-[4 -(9-phenanthryl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: P CPPn) and molybdenum oxide (MoO3) in a weight ratio (PCPPn:MoO3) of 1:0. 5, co-evaporation was carried out to a thickness of 60 nm. The hole transport layer 112 is a vapor deposition method in which the layers are evaporated simultaneously from different evaporation sources. PCPPn was evaporated to a thickness of 30 nm.

[0450] Next, as the light-emitting layer 130, 9-[4-(7-benzo[a]anthracene)phenyl ]-9H-carbazole (abbreviation: 7CzPaBA) was formed to a thickness of 25 nm. Ta.

[0451] On the light-emitting layer 130, an electron transport layer 118 was formed using 2,2'-(pyridine-2,6- Diyl)bis(4,6-diphenylpyrimidine) (abbreviation: 2,6(P2Pm)2Py) Next, lithium fluoride ( LiF) was evaporated to a thickness of 1 nm.

[0452] The electrode 102 is made of aluminum (Al) and is formed to a thickness of 200 nm. Successful.

[0453] Next, in a glove box with a nitrogen atmosphere, a sealing substrate is formed using an organic EL sealing material. The light-emitting element 1 was sealed by fixing the substrate on which the EL layer 100 was formed. A sealing material is applied to the periphery of the EL layer 100 formed on the substrate, and the substrate and a sealing substrate are bonded together. Then, 365 nm ultraviolet light was applied at 6 J / cm 2 The film was irradiated with light and then heat-treated at 80°C for 1 hour. The light-emitting device 1 was obtained through this process.

[0454] <Fabrication of Light-Emitting Element 2, Comparative Light-Emitting Element 1, and Comparative Light-Emitting Element 2> The light-emitting element 2, the comparative light-emitting element 1, and the comparative light-emitting element 2 were fabricated in the same manner as the fabrication of the light-emitting element 1 described above. The only difference is the process of forming the light-emitting layer 130, and the other processes are the same as those of the light-emitting element 1. did.

[0455] The light-emitting layer 130 of the light-emitting element 2 is made of 7CzPaBA and N,N'-bis(3-methyl phenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)fluoren-9-yl]fluoren- [phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn) was added in a weight ratio of ( 7CzPaBA:1,6mMemFLPAPrn) is 1:0.03, and the thickness is 25 nm. In the light-emitting layer 130, 7CzPaBA was used as the host material. , 1,6mMemFLPAPrn is the guest material (fluorescent material).

[0456] The light-emitting layer 130 of the comparative light-emitting element 1 was formed of 7-[4-(10-phenyl-9-anthracene)- [phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA) The thickness was formed to be 25 nm.

[0457] The light-emitting layer 130 of the comparative light-emitting element 2 was made of cgDBCzPA and 1,6mMemFL PAPrn was added at a weight ratio of 1:0.0 (cgDBCzPA:1,6mMemFLPAPrn). 3, co-evaporation was performed to a thickness of 25 nm. zPA is the host material and 1,6mMemFLPAPrn is the guest material (fluorescent material). be.

[0458] Fabricated light-emitting elements (light-emitting element 1, light-emitting element 2, comparative light-emitting element 1, and comparative light-emitting element 2) The details of the element configuration are shown in Table 2.

[0459] [Table 2]

[0460] <Fluorescence lifetime measurement>

[0461] The fabricated light-emitting element 1, light-emitting element 2, comparative light-emitting element 1, and comparative light-emitting element 2 were The light lifetime was measured. In the light-emitting element 1, the blue light emitted by 7CzPaBA was measured as the comparative light The element 1 emits blue light due to cgDBCzPA, while the light-emitting element 2 and comparative light-emitting element 2 emit fluorescent light. The blue light emitted by the optical material 1,6mMemFLPAPrn was observed. A picosecond fluorescence lifetime measurement system (Hamamatsu Photonics) was used. In order to measure the lifetime of the fluorescent light, a rectangular pulse voltage is applied to the light emitting element, and the The decaying light emission was measured with a streak camera in time resolution. By applying a 10Hz frequency and integrating the repeatedly measured data, a high S / N ratio can be achieved. The measurements were carried out at room temperature (300 K) with an applied pulse voltage of 5.0 V (luminescent element Element 1 and Element 2), or 3.5V (Comparative Light-Emitting Element 1 and Comparative Light-Emitting Element 2 In this case, the current flowing through the light-emitting element is set to be the same for all light-emitting elements. The applied pulse voltage was adjusted for each light-emitting element. The negative bias voltage was set to -5V, and the measurement time was set to 50 μs. The results of measuring the optical lifetime are shown in Figures 21(A) and 21(B). The vertical axis represents the light emission when carriers are constantly injected (when the pulse voltage is ON). The horizontal axis indicates the elapsed time from the fall of the pulse voltage. .

[0462] The decay curves shown in Figures 21(A) and 21(B) were fitted with an exponential function. As a result, the fluorescence lifetimes τ of Light-Emitting Device 1 and Light-Emitting Device 2 were 2.1 μs and 2.2 μs, respectively. The fluorescence lifetimes τ of the comparative light-emitting element 1 and the comparative light-emitting element 2 were 3.2 μs and 3.1 μs, respectively. Since the lifetime of fluorescent light is usually a few nanoseconds, the lifetime of the light-emitting element is estimated to be 1 nanosecond. The light-emitting element 2, the comparative light-emitting element 1, and the comparative light-emitting element 2 all contain a fluorescent component containing a delayed fluorescent component. It can be said that photoluminescence is observed.

[0463] In the fluorescence measurements shown in Figures 21(A) and 21(B), the following factors cause delayed fluorescence: In addition to the generation of singlet excitons by triplet-triplet annihilation (TTA), When carriers remain inside an optical element, singlets are formed by the recombination of these remaining carriers. There is a possibility that delayed fluorescence may occur due to exciton generation. However, this measurement is performed under the conditions Since a negative bias voltage (-5V) is applied at Therefore, the delay shown in the measurement results in Figures 21(A) and 21(B) The fluorescent component can be attributed to emission due to triplet-triplet annihilation (TTA).

[0464] Next, the proportion of delayed fluorescence components to all emission components was calculated. Table 3 shows the proportion of light components.

[0465] [Table 3]

[0466] As a result, the proportion of delayed fluorescent components in the light-emitting element 1 was 25%, which was The results showed that the proportion of delayed fluorescence was high. The light-emitting element 1 using 7CzPaBA having an anthracene skeleton in the light-emitting layer has a higher cgMore TTA is generated than in comparative light-emitting element 1, which uses DBCzPA in the light-emitting layer. It can be said that.

[0467] In addition, the proportion of delayed fluorescent components in the light-emitting element 2 was 20%, which was slower than that in the comparative light-emitting element 2. The results showed that the proportion of extended fluorescence was high. Even when observing the emission from 1,6mMemFLPAPrn, ] Light-emitting device 2 using 7CzPaBA with an anthracene skeleton as the host material , from comparative light-emitting element 2 using cgDBCzPA having an anthracene skeleton as the host material It can be said that TTA occurs more frequently in patients with glaucoma than in those with glaucoma.

[0468] <Light-emitting characteristics of light-emitting elements> Next, the light-emitting elements 1, 2, comparative light-emitting elements 1, and 2 were fabricated. The characteristics were measured at room temperature (in an atmosphere maintained at 25°C).

[0469] Here, 1000 cd / m 2 The light-emitting characteristics of the light-emitting element in the vicinity are shown in Table 4 below. The current efficiency vs. luminance characteristics of the light-emitting element are shown in FIG. 22, the external quantum efficiency vs. luminance characteristics are shown in FIG. 23, and the luminance The temperature-voltage characteristics are shown in FIG.

[0470] [Table 4]

[0471] The emission spectrum peak of the light-emitting element 1 is 435 nm, and the emission spectrum of the comparative light-emitting element 1 is 435 nm. The peak of blue light emitted by 7CzPaBA in the light-emitting element 1 is 440 nm. The light-emitting element 1 emitted blue light from cgDBCzPA. The emission spectrum peak of the comparative light-emitting element 2 is 464 nm. The light-emitting element 2 and the comparative light-emitting element 2 contain the fluorescent material 1,6mMemFLPAPr. The blue light emitted from each of the light-emitting elements was observed at 400 nm. It emits blue light with an emission spectrum peak in the wavelength band of 550 nm or less. In addition, in the light-emitting element 2 and the comparative light-emitting element 2, only the light emitted by the fluorescent material was observed. Therefore, the singlet excitation energy generated by TTA is transferred from the host material to the fluorescent material. It can be said that energy is transferred to

[0472] 22, 23, and Table 4, the efficiency of the light-emitting element 1 is higher than that of the comparative light-emitting element 1. It can be seen that the efficiency of the light-emitting element 2 is higher than that of the comparative light-emitting element 2. Light-emitting element 1 and light-emitting element 2, which use 7CzPaBA in the light-emitting layer of the element, have better cgDBC Higher luminous efficiency was obtained than that of comparative light-emitting element 1 and comparative light-emitting element 2 using zPA. In other words, benzo[a]a in which the proportion of delayed fluorescence components due to TTA is 20% or more By using 7CzPaBA, which has a dithracene skeleton, in the light-emitting layer, blue light with high luminous efficiency was obtained. A color light-emitting device was successfully fabricated.

[0473] With the above configuration, the proportion of delayed fluorescence components due to TTA in the luminescent components is 20% or more and to fabricate a light-emitting element having an emission spectrum peak in blue. In addition, if the proportion of delayed fluorescence components due to TTA in the luminescent components is 20% or more, and at least one emission spectrum in the wavelength band of 400 nm to 550 nm It is possible to fabricate a light-emitting device having a peak.

[0474] <Measurement of singlet and triplet excitation energy levels> In the fluorescence measurements shown in Figures 21(A) and 21(B), the following factors cause delayed fluorescence: Thermally activated delayed fluorescence is observed due to reverse intersystem crossing from the triplet excited state to the singlet excited state. For the reverse intersystem crossing to occur efficiently, the energy between the S1 level and the T1 level must be It is preferable that the energy difference is 0.2 eV or less. To confirm that the delayed fluorescence was due to TTA, we The S1 and T1 levels of the materials used in the light-emitting layer of the device were measured.

[0475] Measurements of S1 and T1 levels were performed using 7CzPaBA, cgDBCzPA, and 1,6m The light-emitting element of one embodiment of the present invention is a fluorescent light-emitting element. Fluorescent organic materials are difficult to cause intersystem crossing, and the emission from the T1 level is weak. Therefore, it is sometimes difficult to measure the T1 level. Calculations were also performed.

[0476] First, to estimate the S1 level, a thin film (approximately 50 nm) was deposited on a quartz substrate by vacuum deposition. The thin film was formed and the absorption spectrum was measured. A spectrophotometer (V550 model, manufactured by JASCO Corporation) was used. The absorption spectrum of quartz was subtracted from the absorption spectrum of the thin film. A Tauc plot was created assuming the transition, and the S1 level was estimated from it.

[0477] Next, phosphorescence measurement was carried out to estimate the T1 level. The materials used for the detection have very high fluorescence quantum yields, and thin film samples using the materials alone are It has been very difficult to directly observe phosphorescence using PL measurement. Phosphorescence measurements were carried out using a triplet sensitizer to estimate the T1 level.

[0478] The material used to measure the T1 level is tris(2-phenylpyridinato-N) as a triplet sensitizer. ,C 2’ ) Iridium (III) (abbreviation: Ir(ppy)3) was added to the co-evaporated film. The co-deposition was measured by low-temperature PL measurement, and the T1 level was determined from the measured phosphorescence emission spectrum. The measurement was performed using a micro PL microscope, LabRAM HR-PL (Horiba Co., Ltd.). The measurement temperature was 10 K, and a He-Cd laser (325 nm) was used as the excitation light. A CCD detector was used as the detector. It is difficult to determine the intersystem crossing probability of the fluorescent material without co-evaporation. This makes it possible to measure phosphorescence emission from

[0479] The thin film was formed on a quartz substrate to a thickness of 50 nm, and the quartz substrate was heated in a nitrogen atmosphere. Then, another quartz substrate was attached to the deposition surface side, and the substrate was used for measurement.

[0480] Next, to confirm the T1 level measured by the above method, the T1 level was calculated by quantum chemical calculation. I went out.

[0481] The calculation method is as follows. The quantum chemistry calculation program is Ga The calculation was performed using a high-performance computer (SGI, This was carried out using ICE X.

[0482] The most stable structures in the lowest excited triplet state and the singlet ground state were calculated using density functional theory (DFT). ) was calculated. The basis function was 6-311G(d,p). The functional was B3 LYP was used. The energy distribution of the most stable structure in the singlet ground state and the lowest excited triplet state was calculated. The energy of the T1 level was calculated from the energy difference.

[0483] The measurement results of the S1 level (actual measurement) and the T1 level (actual measurement) estimated as above are The measured and calculated results are shown in Table 5.

[0484] [Table 5]

[0485] From the above results, the T1 level measured by the above method and the value calculated by quantum chemical calculations Therefore, it can be seen that the difference between the T1 level value obtained by this example and The value of the T1 level can be said to be sufficiently reliable.

[0486] Also, from Table 5, the S1 level of 7CzPaBA, which has a benzo[a]anthracene skeleton, is 1,6mMemFLPAPrn, a fluorescent material that emits blue light, as a host material 131. It can be seen that the energy level is high enough to be used as a

[0487] In addition, from Table 5, the energy of the S1 level and T1 level of 7CzPaBA and cgDBCzPA is The energy difference is 0.5 eV or more. The triplet state is the cause of delayed fluorescence. When the thermally activated delayed fluorescence is derived from reverse intersystem crossing from an excited state to a singlet excited state, For reverse intersystem crossing to occur efficiently, the energy difference between the S1 and T1 levels must be 0.2e Therefore, the thickness of the light-emitting layer of the light-emitting device fabricated in this example is preferably 100 μm or less. In the material, the delayed fluorescence component is derived from thermally activated delayed fluorescence. It can be said that it originates from TTA.

[0488] The fluorescence emission spectrum peak of the thin film of 7CzPaBA is 429 nm (2.89 e V), the fluorescence emission spectrum peak of the thin film of cgDBCzPA is 442 nm (2.81 e V). Therefore, the fluorescence emission spectra of 7CzPaBA and cgDBCzPA were The difference in energy equivalent between the peak wavelength of the fluorescent light and the peak wavelength of the phosphorescent emission spectrum is 0.5 This also indicates that the material used in the light-emitting layer of the light-emitting device fabricated in this example In this case, the delayed fluorescence component is not derived from thermally activated delayed fluorescence but from TTA. The PL-EL measurement device ( Hamamatsu Photonics) was used.

[0489] As described above, the proportion of delayed fluorescence components due to TTA is 20% or more, and the luminous efficiency Therefore, a light-emitting element having a blue emission spectrum peak can be fabricated. [Explanation of symbols]

[0490] 100 EL layer 101 Electrode 101a Conductive layer 101b Conductive layer 102 electrode 103 Electrode 103a Conductive layer 103b Conductive layer 104 Electrode 104a conductive layer 104b Conductive layer 105 EL layer 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 123B Light-emitting layer 123G Light-emitting layer 123R luminescent layer 130 Light-emitting layer 131 Host Materials 132 Guest Materials 135 Light-emitting layer 136 Host Materials 137 Guest Materials 140 Bulkhead 150 light-emitting elements 152 Light-emitting element 160 luminescent layer 170 Light-emitting layer 170a Light-emitting layer 170b Light-emitting layer 200 boards 220 board 221B area 221G area 221R area 222B area 222G area 222R area 223 Light blocking layer 224B Optical Elements 224G Optical Element 224R Optical Element 250 light-emitting elements 252 Light-emitting element 254 Light-emitting element 300 Organic semiconductor element 301 Source electrode 302 Drain electrode 303 Gate electrode 330 Active layer 400 EL layer 401 Electrode 402 Electrode 411 Hole injection layer 412 Hole transport layer 413 Electron transport layer 414 Electron injection layer 416 Hole injection layer 417 Hole transport layer 418 Electron transport layer 419 Electron injection layer 420 luminescent layer 421 Host Materials 422 Guest Materials 430 Light-emitting layer 431 Host Materials 431_1 Organic compounds 431_2 Organic compounds 432 Guest Materials 441 Lighting Unit 442 Lighting Unit 445 Charge generation layer 450 light-emitting elements 452 Light-emitting element 801 pixel circuit 802 pixel section 804 Drive circuit section 804a Scanning line driving circuit 804b Signal line driver circuit 806 protection circuit 807 Terminal section 852 transistors 854 transistors 862 Capacitor element 872 Light-emitting element 2000 touch panel 2001 Touch Panel 2501 Display device 2502R pixels 2502t transistor 2503c Capacitive element 2503g Scanning line driver circuit 2503t transistor 2509 FPC 2510 board 2510a Insulating layer 2510b flexible substrate 2510c adhesive layer 2511 Wiring 2519 terminal 2521 Insulation layer 2528 Bulkhead 2550R light emitting element 2560 Sealing layer 2567BM light shielding layer 2567p anti-reflection layer 2567R colored layer 2570 board 2570a Insulating layer 2570b flexible substrate 2570c adhesive layer 2580R Light Emitting Module 2590 board 2591 Electrode 2592 Electrode 2593 Insulation Layer 2594 Wiring 2595 Touch Sensor 2597 Adhesive layer 2598 Wiring 2599 Connection Layer 2601 Pulse voltage output circuit 2602 Current detection circuit 2603 Capacity 2611 Transistor 2612 transistor 2613 Transistor 2621 Electrode 2622 Electrode 8000 Display Module 8001 Top cover 8002 Lower cover 8003 FPC 8004 Touch Sensor 8005 FPC 8006 Display device 8009 Frame 8010 Printed Circuit Board 8011 Battery 8501 Lighting equipment 8502 Lighting equipment 8503 Lighting equipment 8504 Lighting equipment 9000 chassis 9001 Display section 9003 Speaker 9005 Operation key 9006 Connection terminal 9007 Sensor 9008 Microphone 9050 Operation button 9051 Information 9052 Information 9053 Information 9054 Information 9055 Hinge 9100 Mobile Information Terminal 9101 Mobile Information Terminal 9102 Mobile Information Terminal 9200 Mobile Information Terminal 9201 Mobile Information Terminal

Claims

1. A light-emitting layer is disposed between a pair of electrodes, the light-emitting layer includes a first material having an energy difference of 0.5 eV or more between the lowest excited singlet energy level and the lowest excited triplet energy level, and a second material having an emission spectrum peak in a blue wavelength band; the lowest excited triplet energy level of the first material is lower than the lowest excited triplet energy level of the second material; the first material is a compound capable of exhibiting delayed fluorescence and in which a carbazole skeleton is bonded to the 7-position of a benzo[a]anthracene skeleton via an arylene group.

2. A light-emitting layer is disposed between a pair of electrodes, the light-emitting layer comprises a first material having an energy difference of 0.5 eV or more between the lowest excited singlet energy level and the lowest excited triplet energy level, and a second material having at least one emission spectrum peak in a wavelength band of 400 nm or more and 550 nm or less; the lowest excited triplet energy level of the first material is lower than the lowest excited triplet energy level of the second material; the first material is a compound capable of exhibiting delayed fluorescence and in which a carbazole skeleton is bonded to the 7-position of a benzo[a]anthracene skeleton via an arylene group.

3. A light-emitting layer is disposed between a pair of electrodes, the light-emitting layer includes a first material having an energy difference of 0.5 eV or more between the lowest excited singlet energy level and the lowest excited triplet energy level, and a second material having an emission spectrum peak in a blue wavelength band; the lowest excited singlet energy level of the first material is higher than the lowest excited singlet energy level of the second material; the lowest excited triplet energy level of the first material is lower than the lowest excited triplet energy level of the second material; the first material is a compound capable of exhibiting delayed fluorescence and in which a carbazole skeleton is bonded to the 7-position of a benzo[a]anthracene skeleton via an arylene group.

4. A light-emitting layer is disposed between a pair of electrodes, the light-emitting layer comprises a first material having an energy difference of 0.5 eV or more between the lowest excited singlet energy level and the lowest excited triplet energy level, and a second material having at least one emission spectrum peak in a wavelength band of 400 nm or more and 550 nm or less; the lowest excited singlet energy level of the first material is higher than the lowest excited singlet energy level of the second material; the lowest excited triplet energy level of the first material is lower than the lowest excited triplet energy level of the second material; the first material is a compound capable of exhibiting delayed fluorescence and in which a carbazole skeleton is bonded to the 7-position of a benzo[a]anthracene skeleton via an arylene group.

5. In any one of claims 1 to 4, The second material is a light-emitting element having a pyrene skeleton.

6. A light-emitting element according to any one of claims 1 to 5; A display device having a color filter, a seal, or a transistor.

7. The display device according to claim 6 ; An electronic device having a housing or a touch sensor.

8. A light-emitting element according to any one of claims 1 to 5; A lighting device having a housing or a touch sensor.

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