Light-emitting element

Abstract

To provide a light-emitting element with high luminescence efficiency, having a light-emitting material. [Solution] A light-emitting element having a host material and a guest material. The host material is It comprises one organic compound and a second organic compound. The first organic compound is singlet excited. The difference between the energy level and the triplet excitation energy level is greater than 0 eV and less than or equal to 0.2 eV. One of the first organic compound and the second organic compound is the first organic compound and the second Having a HOMO level higher than the HOMO level of the other organic compound, and the first organic compound and the second organic compound has a LUMO level higher than the other LUMO level. The compound forms an excited complex with the second organic compound.

Description

[Technical Field]

[0001] One aspect of the present invention relates to a light-emitting element, or a display device having the light-emitting element, an electronic device, and a light Regarding lighting equipment.

[0002] Furthermore, one aspect of the present invention is not limited to the above-mentioned technical field. One aspect of the technical field relates to a product, method, or method of manufacture. Or, one aspect of the present invention. This refers to a process, machine, manufacture, or composition. Regarding the ter. Therefore, the technical aspects of one aspect of the present invention disclosed more specifically herein Examples include semiconductor devices, display devices, liquid crystal display devices, light-emitting devices, lighting devices, energy storage devices, and memory devices. Examples include devices, methods for driving them, or methods for manufacturing them. . [Background technology]

[0003] In recent years, electroluminescence (EL) Research and development of light-emitting devices using this technology are actively underway. The basic configuration of these light-emitting devices is The device has a configuration in which a layer containing a light-emitting material (EL layer) is sandwiched between a pair of electrodes. By applying a voltage between them, light emission can be obtained from the light-emitting material.

[0004] Since the aforementioned light-emitting element is self-illuminating, the display device using it offers excellent visibility and battery life. It has advantages such as not requiring crystalline materials and consuming less power. Furthermore, it can be manufactured to be thin and lightweight. It also has advantages such as a high response speed.

[0005] An EL layer containing the light-emitting material is provided between a pair of electrodes, using an organic material as the light-emitting material. In the case of optical elements (for example, organic EL elements), by applying a voltage between a pair of electrodes, shadow Electrons are injected from the electrodes and holes from the anode into the light-emitting EL layer, and an electric current flows. The injected electrons and holes then recombine, causing the luminescent organic material to be energized. This creates an excited state, allowing light emission to be obtained from the excited, luminescent organic material.

[0006] The types of excited states that organic materials can form include singlet excited states (S * ) and triplet excited state state(T * ) There are two states: fluorescence from the singlet excited state and phosphorescence from the triplet excited state. It is called [name]. Furthermore, the statistical generation ratio of these in light-emitting elements is S * :T * =1 :3. Therefore, phosphorescence is emitted from a light-emitting element that uses a fluorescent material (fluorescent material). Light-emitting devices that use phosphorescent materials can achieve higher luminescence efficiency. Therefore, using a phosphorescent material capable of converting the energy of the triplet excited state into light emission, The development of light-emitting elements has been actively pursued in recent years (see, for example, Patent Document 1).

[0007] The energy required to excite organic materials depends on the energy of the singlet excited state. However, in light-emitting devices using phosphorescent organic materials, the triplet excitation energy is It is converted into light energy. Therefore, the singlet excited state and triplet excited state formed by organic materials When the energy difference between the initial state and the current state is large, the energy required to excite the organic material is: The energy difference corresponds to the amount of energy that makes the emission energy higher than that of organic materials. The difference between the energy required to excite the material and the energy of light emission is in a light-emitting element. The increase in drive voltage affects the element characteristics, but there are methods to suppress this increase in drive voltage. Development is underway (see Patent Document 2).

[0008] Furthermore, among light-emitting elements using phosphorescent materials, in particular, light-emitting elements that emit blue light... Because it is difficult to develop stable materials with high triplet excitation energy levels, practical applications are still lacking. It has not yet reached this stage. Therefore, development of light-emitting devices using more stable fluorescent materials is underway. Therefore, methods are being explored to improve the luminescence efficiency of light-emitting devices (fluorescent light-emitting devices) using fluorescent materials. ru.

[0009] As a material capable of converting a portion of the energy of the triplet excited state into light emission, thermally active Thermally Activated Delayed Fluorescence A (scence:TADF) form is known. In thermally activated delayed phosphors, the triplet excited state is known. From this, a singlet excited state is generated by reverse intersystem crossing, and from the singlet excited state, it is converted into luminescence. .

[0010] In light-emitting devices using thermally activated delayed phosphors, in order to increase the luminescence efficiency, thermal activation In delayed phosphors, not only is the singlet excited state efficiently generated from the triplet excited state, but The ability to efficiently obtain light emission from singlet excited states, i.e., a high fluorescence quantum yield. This is important. However, designing a light-emitting material that satisfies both conditions simultaneously is difficult. ru.

[0011] Therefore, in a light-emitting element having a thermally activated delayed phosphor and a fluorescent material, This method involves transferring the singlet excitation energy of the extended phosphor to the fluorescent material, thereby obtaining light emission from the fluorescent material. A law has been proposed (see Patent Document 3). [Prior art documents] [Patent Documents]

[0012] [Patent Document 1] Japanese Patent Publication No. 2010-182699 [Patent Document 2] Japanese Patent Publication No. 2012-212879 [Patent Document 3] Japanese Patent Publication No. 2014-45179 [Overview of the project] [Problems that the invention aims to solve]

[0013] In a light-emitting device having a thermally activated delayed phosphor and a light-emitting material, the light-emitting efficiency is increased. Alternatively, in order to reduce the driving voltage, the carriers in the thermally activated delay phosphor can be efficiently... Recombination is preferable.

[0014] Furthermore, in a light-emitting element having a thermally activated delayed phosphor and a fluorescent material, the luminescence efficiency is increased. To achieve this, it is preferable that a singlet excited state is efficiently generated from a triplet excited state. Furthermore, it efficiently converts from the singlet excited state of a thermally activated delayed phosphor to the singlet excited state of a fluorescent material. It is preferable for energy to be transferred.

[0015] Therefore, in one aspect of the present invention, a fluorescent material or phosphorescent material is provided, which has high luminescence efficiency. One objective is to provide an optical element. Alternatively, in one aspect of the present invention, power consumption is reduced. One objective is to provide a light-emitting element that has been modified. Alternatively, in one aspect of the present invention, One of the objectives is to provide a light-emitting element. Alternatively, in one aspect of the present invention, a novel light-emitting element One of the objectives is to provide a device. Alternatively, in one aspect of the present invention, a novel display device is provided. One of the objectives is to provide it.

[0016] Furthermore, the description of the above problems does not preclude the existence of other problems. Also, one aspect of the present invention is not necessarily However, it is not necessary to solve all of these problems. Other issues not mentioned above should be described in the specification, etc. This is self-evident, and it is possible to extract issues other than those mentioned above from the description in the specification, etc. ru. [Means for solving the problem]

[0017] One aspect of the present invention is a light-emitting element having a light-emitting layer that efficiently forms an excited complex. This involves converting triplet excitons into singlet excitons and causing light to be emitted from a material containing singlet excitons. This is a light-emitting element that can do this. Alternatively, the energy transfer of the singlet excitons can cause the light-emitting material to... It is a light-emitting element that can emit light.

[0018] Therefore, one aspect of the present invention is a light-emitting element having a host material and a guest material. The host material has a first organic compound and a second organic compound, and the guest material is The first organic compound has the function of exhibiting fluorescence, and the singlet excitation energy level The difference between the position and the triplet excitation energy level is greater than 0 eV and less than or equal to 0.2 eV, and the first One of the organic compound and the second organic compound is the first organic compound and the second organic compound. Having a HOMO level higher than the other HOMO level, and the first organic compound and the second This is a light-emitting element that has a LUMO level higher than the other LUMO level of the organic compound.

[0019] Another aspect of the present invention is a light-emitting element having a host material and a guest material. The host material comprises a first organic compound and a second organic compound, and the guest material comprises, The first organic compound has the function of exhibiting fluorescence, and the singlet excitation energy level The difference between this and the triplet excitation energy level is greater than 0 eV and less than or equal to 0.2 eV, and the first is One of the first organic compound and the second organic compound is a combination of the first organic compound and the second organic compound. Having an oxidation potential greater than or equal to the other oxidation potential, and the first organic compound and the second organic compound This is a light-emitting element that has a reduction potential greater than or equal to the other reduction potential.

[0020] Another aspect of the present invention is a light-emitting element having a host material and a guest material. The host material comprises a first organic compound and a second organic compound, and the guest material comprises, The first organic compound has the function of converting triplet excitation energy into light emission, The difference between the singlet excitation energy level and the triplet excitation energy level is greater than 0 eV, which is 0.2. The volts are less than or equal to eV, and one of the first organic compound and the second organic compound is the first organic compound. and the second organic compound has a HOMO level higher than the other HOMO level, and the first An organic compound and a second organic compound having a LUMO level higher than the other LUMO level. It is an optical element.

[0021] Another aspect of the present invention is a light-emitting element having a host material and a guest material. The host material comprises a first organic compound and a second organic compound, and the guest material comprises, The first organic compound has the function of converting triplet excitation energy into light emission, The difference between the singlet excitation energy level and the triplet excitation energy level is greater than 0 eV, which is 0.2. The volts are less than or equal to eV, and one of the first organic compound and the second organic compound is the first organic compound. and the second organic compound has an oxidation potential greater than or equal to the oxidation potential of the other organic compound, and the first organic compound This is a light-emitting element having a reduction potential greater than or equal to the reduction potential of the other substance and the second organic compound.

[0022] Furthermore, in each of the above configurations, an excited complex is formed with the first organic compound and the second organic compound. It is preferable to form it.

[0023] That is, another aspect of the present invention comprises a host material and a guest material, and the host material It comprises a first organic compound and a second organic compound, and the guest material exhibits fluorescence. The first organic compound has the function of being able to do so, and the singlet excitation energy level and the triplet excitation energy level The difference from the energy level is greater than 0 eV and less than or equal to 0.2 eV, and the first organic compound and the second This is a light-emitting element that forms an excited complex with two organic compounds.

[0024] Another aspect of the present invention comprises a host material and a guest material, wherein the host material is The guest material comprises a first organic compound and a second organic compound, and the triplet excitation energy - has the function of converting into light emission, and the first organic compound has singlet excitation energy - The difference between the level and the triplet excitation energy level is greater than 0 eV and less than or equal to 0.2 eV, This is a light-emitting element that forms an excited complex with organic compound 1 and organic compound 2.

[0025] Furthermore, in each of the above configurations, the excited complex has the function of exhibiting thermally activated delayed fluorescence at room temperature. This is preferable. Furthermore, the excitation complex has the function of donating excitation energy to the guest material. This is preferable. Furthermore, the emission spectrum exhibited by the excited complex is the absorption spectrum of the guest material. It is preferable that the region overlaps with the lowest energy absorption band.

[0026] Furthermore, in each of the above configurations, the first organic compound exhibits thermally activated delayed fluorescence at room temperature. It is preferable to have the ability to do so.

[0027] Furthermore, in each of the above configurations, one of the first organic compound and the second organic compound is a hole. It has the function of being able to transport the first organic compound and the other of the second organic compound Preferably, it has the function of being able to transport electrons. Also, the first organic compound and One of the second organic compounds has a π-electron-rich heteroaromatic skeleton or a less aromatic amine skeleton. It has at least one, and the other of the first organic compound and the second organic compound is a π-electron-deficient compound. It is preferable that the first organic compound has an elementary aromatic skeleton. Furthermore, the first organic compound is a π-electron-rich heteroaromatic compound. Having at least one of a skeleton or an aromatic amine skeleton, and a π-electron-deficient heteroaromatic skeleton It is preferable to have a certain grade.

[0028] Furthermore, in the above configuration, the π-electron-rich heteroaromatic skeleton is an acridine skeleton, phenoxy Sagin skeleton, phenothiazine skeleton, furan skeleton, thiophene skeleton, and pyrrole skeleton Having one or more selected from among them, the π-electron-deficient heteroaromatic skeleton is diazi It is preferable that the pyrrole skeleton has an indone skeleton or a triazine skeleton. In addition, the pyrrole skeleton is preferably an indone skeleton. 3-(9-phenyl-9H-carbazole-3-yl) skeleton, carbazole skeleton, or 3-(9-phenyl-9H-carbazole-3-yl) It is preferable that it has a )-9H-carbazole skeleton.

[0029] Another aspect of the present invention involves the light-emitting element of each of the above configurations and a color filter or transistor. A display device having at least one of the ZISTA. Another aspect of the present invention is the The electronic device comprises a display device and at least one of a housing or a touch sensor. Furthermore, another aspect of the present invention relates to the light-emitting element of each of the above configurations and a housing or touch sensor. It is a lighting device having at least one of the following. Another aspect of the present invention is a lighting device having a light-emitting element. This includes not only optical devices but also electronic devices that have light-emitting devices. Therefore, in this specification A light-emitting device refers to an image display device or a light source (including lighting devices). The device has connectors, such as FPC (Flexible Printed Circuit). ), a display module with a TCP (Tape Carrier Package) attached. A display module with a printed circuit board attached to the TCP, or a light-emitting element with CO2 The G (Chip On Glass) method allows for the direct mounting of ICs (integrated circuits) in the display. Joule may also include a light-emitting device. [Effects of the Invention]

[0030] According to one aspect of the present invention, a light-emitting element having a fluorescent material or phosphorescent material and having high luminescence efficiency is provided. It can be provided. Alternatively, according to one aspect of the present invention, a light-emitting element with reduced power consumption can be provided. It can be provided. Or, according to one aspect of the present invention, a novel light-emitting element can be provided. This is possible. Alternatively, according to one aspect of the present invention, a novel light-emitting device can be provided. Alternatively, according to one aspect of the present invention, a novel display device can be provided.

[0031] Furthermore, the description of these effects does not preclude the existence of other effects. One aspect of the present invention is: It is not necessarily required to have all of these effects. Other effects are described in the specification. This is obvious from the descriptions in the specifications, drawings, and claims, and the descriptions in the specifications, drawings, and claims Therefore, it is possible to extract effects other than those mentioned above. [Brief explanation of the drawing]

[0032] [Figure 1] A schematic cross-sectional view of a light-emitting element according to one embodiment of the present invention, and a diagram illustrating the correlation of energy levels in the light-emitting layer. [Figure 2] A diagram illustrating the correlation of energy bands in the light-emitting layer of a light-emitting element according to one embodiment of the present invention. [Figure 3] A diagram illustrating the correlation of energy levels in the light-emitting layer of a light-emitting element according to one embodiment of the present invention. [Figure 4] A schematic cross-sectional view of a light-emitting element according to one embodiment of the present invention, and a diagram illustrating the correlation of energy levels in the light-emitting layer. [Figure 5] A schematic cross-sectional view of a light-emitting element according to one embodiment of the present invention, and a diagram illustrating the correlation of energy levels in the light-emitting layer. [Figure 6] A schematic cross-sectional view of a light-emitting element according to one embodiment of the present invention. [Figure 7] A schematic cross-sectional view of a light-emitting element according to one embodiment of the present invention. [Figure 8] A schematic cross-sectional view of a light-emitting element according to one embodiment of the present invention. [Figure 9] A schematic cross-sectional diagram illustrating a method for manufacturing a light-emitting element according to one embodiment of the present invention. [Figure 10] A schematic cross-sectional diagram illustrating a method for manufacturing a light-emitting element according to one embodiment of the present invention. [Figure 11] A top view and a schematic cross-sectional view illustrating a display device according to one embodiment of the present invention. [Figure 12] A schematic cross-sectional view illustrating a display device according to one embodiment of the present invention. [Figure 13] A schematic cross-sectional view illustrating a display device according to one embodiment of the present invention. [Figure 14] A schematic cross-sectional view illustrating a display device according to one embodiment of the present invention. [Figure 15] A schematic cross-sectional view illustrating a display device according to one embodiment of the present invention. [Figure 16] A schematic cross-sectional view illustrating a display device according to one embodiment of the present invention. [Figure 17] A schematic cross-sectional view illustrating a display device according to one embodiment of the present invention. [Figure 18] A schematic cross-sectional view illustrating a display device according to one embodiment of the present invention. [Figure 19] A schematic cross-sectional view illustrating a display device according to one embodiment of the present invention. [Figure 20] A block diagram and a circuit diagram illustrating a display device according to one embodiment of the present invention. [Figure 21] A circuit diagram illustrating the pixel circuit of a display device according to one embodiment of the present invention. [Figure 22] A circuit diagram illustrating the pixel circuit of a display device according to one embodiment of the present invention. [Figure 23] A perspective view showing an example of a touch panel according to one aspect of the present invention. [Figure 24] A cross-sectional view showing an example of a display device and a touch sensor according to one embodiment of the present invention. [Figure 25] A cross-sectional view showing an example of a touch panel according to one aspect of the present invention. [Figure 26] A block diagram and timing chart diagram of a touch sensor according to one aspect of the present invention. [Figure 27] A circuit diagram of a touch sensor according to one aspect of the present invention. [Figure 28] A perspective view illustrating a display module according to one embodiment of the present invention. [Figure 29] A diagram illustrating an electronic device according to one embodiment of the present invention. [Figure 30] A diagram illustrating an electronic device according to one embodiment of the present invention. [Figure 31] A perspective view illustrating a display device according to one embodiment of the present invention. [Figure 32] A perspective view and a cross-sectional view illustrating a light-emitting device according to one embodiment of the present invention. [Figure 33] A cross-sectional view illustrating a light-emitting device according to one embodiment of the present invention. [Figure 34] A diagram illustrating a lighting device and electronic equipment according to one embodiment of the present invention. [Figure 35] A diagram illustrating a lighting device according to one embodiment of the present invention. [Figure 36] A diagram illustrating the brightness-current density characteristics of a light-emitting element according to an embodiment. [Figure 37] A diagram illustrating the brightness-voltage characteristics of a light-emitting element according to an embodiment. [Figure 38] A diagram illustrating the current efficiency-luminance characteristics of a light-emitting element according to an embodiment. [Figure 39] A diagram illustrating the power efficiency-luminance characteristics of a light-emitting element according to an embodiment. [Figure 40] A diagram illustrating the external quantum efficiency-luminance characteristics of a light-emitting element according to an embodiment. [Figure 41] A diagram illustrating the electroluminescence spectrum of a light-emitting element according to an embodiment. [Figure 42] A diagram illustrating the emission spectrum of a thin film according to the example. [Figure 43] A diagram illustrating the emission spectrum of a thin film according to the example. [Figure 44] A diagram illustrating the emission spectrum of a thin film according to the example. [Figure 45] A diagram illustrating the emission spectrum of a thin film according to the example. [Figure 46] A diagram illustrating the emission spectrum of a thin film according to the example. [Figure 47] A diagram illustrating the emission spectrum of a thin film according to the example. [Figure 48] A diagram illustrating the emission spectrum of a thin film according to the example. [Figure 49] A diagram illustrating the NMR chart of a compound, as shown in the example. [Figure 50] A diagram illustrating the NMR chart of a compound, as shown in the example. [Figure 51] A diagram illustrating the NMR chart of a compound, as shown in the example. [Modes for carrying out the invention]

[0033] The embodiments of the present invention will be described in detail below with reference to the drawings. However, the present invention is as follows The description is not limited to the present invention, and the form and details may not depart from the spirit and scope of the present invention. It is possible to change this in various ways. Therefore, the present invention can be described in the embodiments shown below. It is not interpreted as being limited to volume.

[0034] For the sake of ease of understanding, the position, size, and scope of each component shown in the drawings, etc., are as follows: The actual location, size, and range may not be represented. Therefore, the disclosed invention may not reflect the actual location, size, or range. It is not necessarily limited to the location, size, or scope disclosed in drawings, etc.

[0035] Furthermore, in this specification, the ordinal numbers used as "1st," "2nd," etc., are used for convenience. The order of processes or stacking may not be indicated. For example, "the first" may be written as "the second" or This can be replaced with "third," etc., as appropriate in the explanation. The ordinal numbers used to specify one aspect of this invention may not be the same. be.

[0036] Furthermore, in this specification and other documents, when describing the structure of the invention using drawings, the same thing is used The symbols used may be consistent across different drawings.

[0037] Furthermore, in this specification, the terms "membrane" and "layer" are interchangeable. It is possible to change the term. For example, the term "conductive layer" can be changed to the term "conductive film." It may be possible to change it. Or, for example, change the term "insulating film" to "insulating layer". In some cases, it may be possible to change the terminology to this.

[0038] In this specification, etc., the singlet excited state (S * ) is a single with excitation energy It refers to a singlet state. Furthermore, the S1 level is the lowest singlet excitation energy level. This refers to the lowest singlet excited state's excitation energy level. Also, the triplet excited state... (T * ) is a triplet state that has excitation energy. Also, the T1 level is a triplet state. This is the lowest level of the term excitation energy levels, and the excitation energy of the lowest triplet excited state. This refers to an energy level. In this specification, the terms "singlet excited state" or "singlet excited state" may be used interchangeably. Even when referred to as energy levels, it represents the lowest singlet excited state or S1 level. There are cases where this is incorrect. Also, when simply referred to as a triplet excited state or triplet excited energy level... Even so, it may represent the lowest triplet excited state or T1 level.

[0039] Furthermore, in this specification, a fluorescent material is defined as a material that relaxes from a singlet excited state to a ground state. It is a material that emits light in the visible light region. On the other hand, phosphorescent materials are materials that emit light from the triplet excited state to the ground state. It is a material that emits light in the visible light region at room temperature when it relaxes to a certain state. In other words, phosphorus Optical materials are materials that can convert triplet excitation energy into visible light.

[0040] Furthermore, the emission energy of thermally activated delayed fluorescence is the emission at the shortest wavelength of the thermally activated delayed fluorescence. It can be derived from the peak (including the shoulder). Also, the phosphorescence emission energy and The triplet excitation energy corresponds to the shortest wavelength emission peak (including the shoulder) of phosphorescence. It can be derived from this. Note that the phosphorescence emission occurs in a low-temperature environment (e.g., 10K). Therefore, it can be observed by performing time-resolved photoluminescence.

[0041] In this specification, room temperature refers to any temperature between 0°C and 40°C.

[0042] Furthermore, in this specification, the blue wavelength region refers to waves between 400 nm and 490 nm. It is a long wavelength region, and blue emission means that there is at least one emission spectral peak in that wavelength region. This is the type of light emission. Furthermore, the green wavelength region refers to the wavelength range between 490 nm and less than 580 nm. Therefore, green emission is defined as emission having at least one emission spectral peak in the wavelength region. It is light. Furthermore, the red wavelength range is the wavelength range between 580 nm and 680 nm. Red emission is defined as emission having at least one emission spectral peak in the wavelength region. ru.

[0043] (Embodiment 1) In this embodiment, a light-emitting element according to one aspect of the present invention will be described below using Figures 1 to 3. I will reveal it.

[0044] <Example of light-emitting element configuration> First, regarding the configuration of a light-emitting element according to one aspect of the present invention, using Figures 1(A), (B), and (C) I will explain below.

[0045] Figure 1(A) is a schematic cross-sectional view of a light-emitting element 150 according to one embodiment of the present invention.

[0046] The light-emitting element 150 has a pair of electrodes (electrode 101 and electrode 102), and between the pair of electrodes It has an EL layer 100 provided therein. The EL layer 100 has at least an emissive layer 130. .

[0047] Furthermore, the EL layer 100 shown in Figure 1(A) includes, in addition to the light-emitting layer 130, a hole injection layer 111, and It has functional layers such as a pore transport layer 112, an electron transport layer 118, and an electron injection layer 119.

[0048] In this embodiment, of the pair of electrodes, electrode 101 is used as the anode, and electrode 1 Although 02 is described as the cathode, this is not the case for the configuration of the light-emitting element 150. Then, electrode 101 is used as the cathode and electrode 102 as the anode, and the stacking of each layer between these electrodes is done in the reverse order. It may also be arranged in this order. That is, from the anode side, a hole injection layer 111, a hole transport layer 112, and The order in which the optical layer 130, electron transport layer 118, and electron injection layer 119 are stacked should be as follows. .

[0049] Note that the configuration of the EL layer 100 is not limited to the configuration shown in Figure 1(A), and the hole injection layer 111 At least one of the hole transport layer 112, electron transport layer 118, and electron injection layer 119 selected It is sufficient to have a configuration that has one of either. Alternatively, the EL layer 100 can be a hole or electron injection To reduce barriers, improve hole or electron transport, or inhibit hole or electron transport. It has a functional layer that has functions such as being able to suppress the quenching phenomenon caused by electrodes. It may also be configured as follows. Note that even if each functional layer is a single layer, a configuration in which multiple layers are stacked may also be possible. It may be possible.

[0050] Figure 1(B) is a schematic cross-sectional view showing an example of the light-emitting layer 130 shown in Figure 1(A). The light-emitting layer 130 shown in B) has a host material 131 and a guest material 132. The host material 131 comprises organic compound 131_1 and organic compound 131_2.

[0051] Furthermore, as the guest material 132, any luminescent organic material may be used. Preferably, the material is one that can emit fluorescence (hereinafter also referred to as a fluorescent material). In the following explanation, we will describe a configuration using a fluorescent material as guest material 132. I will explain this further. Note that guest material 132 may be interpreted as a fluorescent material.

[0052] In one embodiment of the present invention, the light-emitting element 150 comprises a pair of electrodes (electrode 101 and electrode 102 By applying a voltage between them, electrons are released from the cathode and holes from the anode. The electrons and holes are injected into the EL layer 100, and an electric current flows. Then, the injected electrons and holes recombine. By doing so, excitons are formed. This is produced by the recombination of carriers (electrons and holes). Of the excitons produced, the ratio of singlet excitons to triplet excitons (hereinafter referred to as the exciton production probability) is statistically determined. The probability ratio is 1:3. Therefore, in a light-emitting device using a fluorescent material, The proportion of singlet excitons that contribute to emission is 25%, while the proportion of triplet excitons that do not contribute to emission is 25%. The proportion of these generated is 75%. Therefore, triplet excitons that do not contribute to luminescence are used for luminescence. Converting to singlet excitons is important for improving the luminescence efficiency of light-emitting devices. That is the case.

[0053] <Light-emitting mechanism of light-emitting element> Next, the light-emitting mechanism of the light-emitting layer 130 will be explained below.

[0054] The organic compound 131_1 and organic compound contained in the host material 131 in the light-emitting layer 130 Substance 131_2 is an excited complex (exciplex, exciplex or Excipl Forms an ex (also called ex).

[0055] The combination of organic compound 131_1 and organic compound 131_2 forms an excited complex. Any combination that allows for this is acceptable, but one of them must have the function of transporting holes (hole transportability). It is a compound that does one function, and the other is a compound that has the function of transporting electrons (electron transport properties). However, this is more preferable. In this case, it becomes easier to form a donor-acceptor type excitation complex. Excited complexes can be formed efficiently.

[0056] Furthermore, as for the combination of organic compound 131_1 and organic compound 131_2, one of them is The other is the Highest Occupied Molecular Orb It has a HOMO level above the ital (also called HOMO) level, and the other lowest unspaced orbit (Lowest Unoccupied Molecular Orbital, LUM It is preferable to have a LUMO level of level O or higher.

[0057] For example, organic compound 131_1 has hole transport properties, and organic compound 131_2 has electron transport properties. When it possesses this property, as shown in the energy band diagram in Figure 2(A), organic compound 131_1 The HOMO level of is above the HOMO level of organic compound 131_2, and the organic compound The LUMO level of 131_1 is preferably higher than or equal to the LUMO level of organic compound 131_2. It seems so. Alternatively, organic compound 131_2 has hole transport properties, and organic compound 131_1 When it has electron transport properties, as shown in the energy band diagram in Figure 2(B), organic compound 1 The HOMO level of 31_2 is above the HOMO level of organic compound 131_1, and also The LUMO level of organic compound 131_2 is higher than or equal to the LUMO level of organic compound 131_1. This is preferable. In this case, the organic compound 131_1 and the organic compound 131_2 are formed The excited complex roughly corresponds to the energy difference between one HOMO level and the other LUMO level. It becomes an excited complex with excitation energy. Also, the HOMO level of organic compound 131_1 and The difference between the HOMO level of organic compound 131_2 and the LUMO level of organic compound 131_1 The difference between the LUMO level of the organic compound 131_2 and the LUMO level of the organic compound 131_2 is preferably 0.2 eV or greater. , more preferably 0.3eV or higher. Note that in Figures 2(A) and 2(B), Host( 131_1) represents organic compound 131_1, and Host(131_2) represents organic compound 13 This is a notation and symbol representing 1_2.

[0058] Furthermore, based on the relationship between the HOMO and LUMO levels described above, organic compound 131_1 and In combination with compound 131_2, one has an oxidation potential greater than the oxidation potential of the other. Furthermore, it is preferable that the reduction potential is greater than or equal to that of the other.

[0059] For example, organic compound 131_1 has hole transport properties, and organic compound 131_2 has electron transport properties. When it has the property, the oxidation potential of organic compound 131_1 is equal to the oxidation potential of organic compound 131_2. The following conditions apply, and the reduction potential of organic compound 131_1 is equal to the reduction potential of organic compound 131_2. It is preferable that it is below the rank. Alternatively, the organic compound 131_2 has hole transport properties and When organic compound 131_1 has electron transport properties, the oxidation potential of organic compound 131_2 is The oxidation potential of organic compound 131_1 is less than or equal to the reduction potential of organic compound 131_2, It is preferable that the oxidation potential and reduction potential are below the reduction potential of organic compound 131_1. The position can be measured by cyclic voltammetry (CV).

[0060] Furthermore, the combination of organic compound 131_1 and organic compound 131_2 exhibits hole transport properties. In the case of a combination of a compound that possesses electron transport properties and a compound that has electron transport properties, the mixing ratio of the two compounds... This makes it possible to easily control the carrier balance. Specifically, it has hole transport properties. Compounds: Compounds with electron transport properties = preferably in the range of 1:9 to 9:1 (by weight). Furthermore, having this configuration makes it easy to control the career balance. Furthermore, the carrier recombination region can be easily controlled.

[0061] Furthermore, it is preferable that the organic compound 131_1 is a thermally activated delayed phosphor. Alternatively, Preferably, it has the function of exhibiting thermally activated delayed fluorescence at room temperature. Organic compound 131_1, on its own, is in a triplet excited state, and then, through reverse intersystem crossing, it is in a singlet excited state. It is a material that can generate [something]. To do so, singlet excitation energy levels and triplet excitation energy levels are required. It is preferable that the difference from the Ghee level is greater than 0 eV and 0.2 eV or less. If 131_1 has the function of converting triplet excitation energy into singlet excitation energy Often, thermally activated delayed fluorescence is not required.

[0062] Furthermore, organic compound 131_1 has a hole-transporting skeleton and an electron-transporting skeleton. It is preferable that the above is present. Furthermore, the organic compound 131_1 is a π-electron-rich heteroaromatic compound. Having at least one of a skeleton or an aromatic amine skeleton, and a π-electron-deficient heteroaromatic skeleton It is preferable that it has a grade. Furthermore, a π-electron-rich complex aromatic skeleton and a π-electron-deficient complex aromatic skeleton are preferable. Direct bonding with the aromatic skeleton results in both donor properties and π-electron deficiency for π-electron-rich complex aromatic skeletons. The acceptor properties of the complex aromatic skeleton are both strengthened, and the singlet excitation energy levels and triple This is particularly preferable because the difference in the excitation energy levels becomes smaller. Organic compound 131_1, Due to its strong donor and acceptor properties, organic compound 131_1 and organic compound This facilitates the formation of a donor-acceptor type excitation complex with 131_2.

[0063] Furthermore, the region where the HOMO molecular orbital is distributed in organic compound 131_1 and the LUMO It is preferable that the overlap with the region where molecular orbitals are distributed is small. It can represent the spatial distribution of electrons within a molecule and the probability of finding an electron. Molecular orbitals, It is possible to describe in detail the electron configuration of a molecule (the spatial distribution and energy of electrons). be.

[0064] The excited complex formed by organic compound 131_1 and organic compound 131_2 is formed by one of the organic compounds Because the compound has a HOMO molecular orbital and the other organic compound has a LUMO molecular orbital. The overlap between the HOMO molecular orbital and the LUMO molecular orbital is extremely small. The resulting complex exhibits a smaller difference between the singlet excitation energy level and the triplet excitation energy level. Therefore, the excited complex formed by organic compound 131_1 and organic compound 131_2 is three The difference between the doublet excitation energy level and the singlet excitation energy level is preferably greater than 0 eV. It is less than 0.2 eV.

[0065] Here, in the light-emitting layer 130, organic compound 131_1 and organic compound 131_2, Figure 1(C) shows the energy level correlation with material 132. The notation and symbols are as follows: ·Host(131_1): Host material (organic compound 131_1) ·Host(131_2): Host material (organic compound 131_2) • Guest (132): Guest material 132 (fluorescent material) ·S H1 : S1 level of host material (organic compound 131_1) ·T H1 : T1 level of the host material (organic compound 131_1) ·S H2 : S1 level of the host material (organic compound 131_2) ·T H2 : T1 level of the host material (organic compound 131_2) ·S G : S1 level of the guest material 132 (fluorescent material) ·T G : T1 level of the guest material 132 (fluorescent material)[[ID=2)]] ·S E : S1 level of the exciplex ·T E : T1 level of the exciplex

[0066] In the light-emitting device according to one aspect of the present invention, an exciplex is formed between the organic compound 131_1 and the organic compound 131_2 included in the light-emitting layer 130. The S1 level (S k<00)0015>) of the exciplex and the T1 level (T [[ID=)7]] of the exciplex E ) are adjacent energy levels to each other (see Route E 3 in FIG. 1(C)).

[0067] An exciplex is an excited state composed of two types of substances. In the case of photoexcitation, it is formed by the interaction between one substance in the excited state and the other substance in the ground state. And when it returns to the ground state by emitting light, the two substances that formed the exciplex behave as the original separate substances again. In the case of electrical excitation, when one becomes excited, it quickly forms an exciplex by interacting with the other. Alternatively, when one receives a hole and the other receives an electron, they can quickly form an exciplex by interacting with each other. In this case, an exciplex can be formed in any of the substances without forming an excited state alone, so most of the excited states formed in the light-emitting layer 130 are exciplexes, and and This makes it possible for the excited complex to exist at its excitation energy level (S E and T E )teeth, Each organic compound that forms an excited complex (organic compound 131_1 and organic compound 131_2) S1 level (S H1 and S H2 ) is lower, therefore the host has a lower excitation energy. This makes it possible to form an excited state of material 131. This enables the driving of the light-emitting element 150. Dynamic voltage can be reduced.

[0068] S1 level of excited complex (S E ) and T1 level (T E ) are in adjacent energy levels Therefore, the excited complex has the function of exhibiting thermally activated delayed fluorescence. That is, the excited complex is three The singlet excitation energy is obtained by reverse intersystem crossing (upconversion) It has the function of converting to (see Figure 1(C) Route E4). Therefore, the light-emitting layer 130 A portion of the triplet excitation energy generated is converted into singlet excitation energy by the excitation complex. To achieve this, the S1 level (S) of the excited complex must be raised. E ) and T1 level (T E ) Energy difference It is preferable that the value is greater than 0 eV and less than or equal to 0.2 eV.

[0069] Also, the S1 level of the excited complex (S E ) is the S1 level (S G ) higher Preferably, the singlet excitation energy of the generated excited complex is Body S1 level (S E ) from guest material 132 S1 level (S G ) to transfer energy This can be achieved. As a result, guest material 132 enters a singlet excited state and emits light (Figure 1(C) (See Route E5).

[0070] To efficiently obtain luminescence from the singlet excited state of guest material 132, guest material 13 The fluorescence quantum yield of step 2 is preferably high, specifically preferably 50% or more, more preferably The percentage is 70% or more, and more preferably 90% or more.

[0071] Furthermore, in order to efficiently generate reverse intersystem crossing, the T1 level (T) of the excited complex is E ) but encourage Each organic compound that forms the complex (organic compound 131_1 and organic compound 131_2) T1 level (T H1 and T H2 It is preferable that it be lower than ). This will allow each organic compound This makes it less likely for the triplet excitation energy of the excited complex to quench, and allows for efficient reverse intersystem interaction. A difference will occur.

[0072] For example, in at least one of the compounds that form an excited complex, S1 level and T1 level When the difference with the position is large, the T1 level of the excited complex (T E ) is further than the T1 level of each compound. It is necessary to set the energy level to a low level. Also, the difference between the S1 level and the T1 level of the excited complex is It is preferable that the S1 level of the guest material is small and lower than the S1 level of the excited complex. When the difference between the S1 and T1 levels of at least one compound is large, a high one Materials with multiplet excitation energy levels, i.e., materials with high emission energy such as blue light. It becomes difficult to use a material that exhibits luminescence as the guest material 132.

[0073] On the other hand, in one aspect of the present invention, organic compound 131_1 is S1 level (S H1 ) and T1 Level (TH1 The difference between the S1 and T1 levels of organic compound 131_1 is small. It is possible to simultaneously increase both of these factors, thereby raising the T1 level of the excited complex. Therefore, one aspect of the present invention is not limited to the emission color of the guest material 132, but for example, blue. From light with high emission energy such as red to light with low emission energy such as red Therefore, it can be suitably used in light-emitting devices that exhibit various types of light emission.

[0074] Furthermore, when the organic compound 131_1 has a skeleton with strong donor properties, it can be injected into the light-emitting layer 130. The holes that are created are injected into organic compound 131_1, making them easier to transport. Compound 131_2 is an acceptor that has stronger acceptor properties than organic compound 131_1. It is preferable that it has a sex skeleton. In this way, organic compound 131_1 and organic compound 131 With _2, it becomes easier to form an excited complex. Alternatively, organic compound 131_1 acts as an acceptor. When it has a strong skeleton, electrons injected into the light-emitting layer 130 into the organic compound 131_1 It becomes easier to inject and transport. At this time, organic compound 131_2 becomes organic compound 131_ It is preferable to have a donor skeleton with stronger donor properties than 1. Compound 131_1 and organic compound 131_2 are more likely to form an excited complex.

[0075] Furthermore, organic compound 131_1, in its elemental form, undergoes reverse intersystem crossing to achieve a triplet excitation energy of 1 It has the function of converting to multiplet excitation energy, and organic compound 131_1 is organic compound 1 When the configuration is such that it is difficult to form an excited complex with 31_2, for example, the H of organic compound 131_1 The OMO level is higher than the HOMO level of organic compound 131_2, and organic compound 131_ When the LUMO level of 2 is higher than the LUMO level of the organic compound 131_1, in the light-emitting layer 130 Both the electrons and holes, which are the injected carriers, are easily injected into and transported through the organic compound 131_1 In this case, it is necessary to control the carrier balance in the light-emitting layer 130 according to the hole transporting property and electron transporting property of the organic compound 131_1. Therefore, the organic compound 131_1 needs to have a molecular structure that, in addition to having the function of converting triplet excitation energy into singlet excitation energy by itself, has a suitable carrier balance, which makes the design of the molecular structure difficult. On the other hand, in one aspect of the present invention, since electrons are injected into and transported through one of the organic compound 131_1 and the organic compound 131_2, and holes are injected into and transported through the other, it is possible to easily control the carrier balance according to the mixing ratio, and a light-emitting device with high luminous efficiency can be provided. In addition, for example, when the HOMO level of the organic compound 131_2 is higher than the HOMO level of the organic compound 131_1, and the LUMO level of the organic compound 131_1 is higher than the LUMO level of the organic compound 131_2, both the electrons and holes, which are the injected carriers in the light-emitting layer 130, are easily injected into and transported through the organic compound 131_2. Therefore, carrier recombination is likely to occur in the organic compound 131_2. When the organic compound 131_2 does not have the function of converting triplet excitation energy into singlet excitation energy by reverse intersystem crossing by itself, it is difficult to convert the triplet excitation energy of the excitons directly generated by carrier recombination into singlet excitation energy. Therefore, it is difficult to utilize for light emission other than the singlet excitation energy among the excitons directly generated by carrier recombination. On the other hand, in the present invention

[0076] Also, for example, when the HOMO level of the organic compound 131_2 is higher than the HOMO O level of the organic compound 131_1, and the LUMO level of the organic compound 131_1 is higher than the LUMO level of the organic compound 131_2, both the electrons and holes, which are the injected carriers in the light-emitting layer 130, are easily injected into and transported through the organic compound 131_2. Therefore, carrier recombination is likely to occur in the organic compound 131_2. When the organic compound 131_2 does not have the function of converting triplet excitation energy into singlet excitation energy by reverse intersystem crossing by itself, it is difficult to convert the triplet excitation energy of the excitons directly generated by carrier recombination into singlet excitation energy. Therefore, it is difficult to utilize for light emission other than the singlet excitation energy among the excitons directly generated by carrier recombination. On the other hand, in the present invention When the triplet excitation energy of the excitons directly generated by carrier recombination cannot be converted into singlet excitation energy, it becomes difficult. Therefore, among the excitons directly generated by carrier recombination, it is difficult to use those other than the singlet excitation energy for light emission. On the other hand, in the present invention Among the excitons directly generated by carrier recombination, it is difficult to use those other than the singlet excitation energy for light emission. On the other hand, in the present invention In one aspect of the disclosure, an exciplex is formed between organic compound 131_1 and organic compound 131_2, and the triplet excitation energy is converted into singlet excitation energy by reverse intersystem crossing. Therefore, it is possible to provide a light-emitting device with high luminous efficiency and high reliability.

[0077] In FIG. 1(C), the case where the S1 level of organic compound 131_2 is higher than the S1 level of organic compound 131_1 and the T1 level of organic compound 131_1 is higher than the T1 level of organic compound 131_2 is illustrated. However, one aspect of the present invention is not limited thereto. For example, as shown in FIG. 3(A), even if the S1 level of organic compound 131_1 is higher than the S1 level of organic compound 131_2 and the T1 level of organic compound 131_1 is higher than the T1 level of organic compound 131_2. Alternatively, as shown in FIG. 3(B), the S1 levels of organic compound 131_1 and organic compound 131_2 may be about the same. In any case, in order to efficiently cause reverse intersystem crossing, it is preferable that the T1 level of the exciplex is lower than the T1 levels of each organic compound (organic compound 131_1 and organic compound 131_2) forming the exciplex. In the process of forming the exciplex, first, reverse intersystem crossing occurs in organic compound 131_1, and after the proportion of the singlet excited state (having the energy level of S) of organic compound 131_1 increases, the singlet exciplex (S) H1 E ​​​​​​​​​​​​​​(having the energy levels) is generated (then energy transfer to the guest) The process of movement is also effective in improving efficiency. In this case, the T1 level of organic compound 131_1 ( T H1 ) is better than the T1 level of organic compound 131_2 (T H2 ) is preferable to be larger. Therefore, the configuration shown in Figure 3(C) is preferred.

[0078] Note that the S1 level of the excited complex (S E ) from the T1 level of guest material 132 (T G ) to Energy transfer is a direct transition from the singlet ground state to the triplet excited state in guest material 132. Because the transition is forbidden, it is unlikely to become the primary energy transfer process.

[0079] Also, the T1 level of the excited complex (T E ) from guest material 132 T1 level (T G ) Triple term When excitation energy transfer occurs, the triplet excitation energy is deactivated (Figure 1(C)). (See Route E6). Therefore, the less energy transfer there is in Route E6, the better for guest material 1. The efficiency of generating the 32 triplet excited states can be reduced, and thermal deactivation can be decreased. Therefore, it is preferable. For this purpose, the weight ratio of the host material 131 to the guest material 132 is It is preferable that the weight ratio of host material 132 is low, specifically the weight ratio of host material 131 The weight ratio of material 132 is preferably 0.001 or more and 0.05 or less. The value is 0.001 or more and 0.03 or less, more preferably 0.001 or more and 0.01 or less. .

[0080] Furthermore, when the direct carrier recombination process becomes dominant in guest material 132, the emissive layer In 130, triplet excitons will be generated in large numbers, and the luminescence efficiency will be impaired by thermal deactivation. Therefore, rather than the process of direct recombination of carriers in the guest material 132, it is preferable that the proportion of the energy transfer process (routes E4 and E5 in FIG. 1(C)) via the generation process of the exciplex is higher, as it can reduce the generation efficiency of the triplet excited state of the guest material 132 and suppress thermal deactivation. For this purpose, the weight ratio of the host material 131 to the guest material 132 is preferably low for the guest material 132. Specifically, the weight ratio of the guest material 132 to the host material 131 is preferably 0.001 or more and 0. 05 or less, more preferably 0.001 or more and 0.03 or less, and even more preferably 0.001 or more and 0.01 or less. As described above, if all of the energy transfer processes of the above-mentioned routes E4 and E5 occur efficiently, both the singlet excitation energy and the triplet excitation energy of the host material 131 will be efficiently converted into the energy of the singlet excited state of the guest material 132, so that the light-emitting device 150 can emit light with high luminescence efficiency. The processes of routes E3, E4, and E5 shown above are referred to as ExSET (

[0081] Exciplex-Singlet Energy Transfer) or ExEF (Exciplex-Enhanced Fluorescence) in this specification and the like. In other words, there is a donation of excitation energy from the exciplex to the guest material 132 in the light-emitting layer 130. By configuring the light-emitting layer 130 as described above, the light emission from the guest material 132 in the light-emitting layer 130 can be achieved with high luminescence efficiency.

[0082] <00,00963>The processes of routes E3, E4, and E5 shown above are referred to as ExSET ( Exciplex-Singlet Energy Transfer) or ExEF (Exciplex-Enhanced Fluorescence) in this specification and the like. In other words, there is a donation of excitation energy from the exciplex to the guest material 132 in the light-emitting layer 130. There is a donation of excitation energy from the exciplex to the guest material 132.

[0083] By configuring the light-emitting layer 130 as described above, the light emission from the guest material 132 in the light-emitting layer 130 It can be obtained efficiently.

[0084] <Energy transfer mechanism> Next, the control of the intermolecular energy transfer process between the host material 131 and the guest material 132. Let's explain the factors. The mechanism of energy transfer between molecules is the Förster mechanism (bi Two mechanisms have been proposed: the polar-dipole interaction and the Dexter mechanism (electron exchange interaction). Here, the intermolecular energy transfer between the host material 131 and the guest material 132 is described. The process will be explained below, and the same applies when the host material 131 is an excited complex.

[0085] ≪Förster mechanism≫ In the Förster mechanism, energy transfer does not require direct contact between molecules, and the host Energy transfer occurs through the resonance phenomenon of dipole vibrations between material 131 and guest material 132. This is due to the resonance phenomenon of dipole oscillation, which transfers energy from the host material 131 to the guest material 132. The excited host material 131 returns to the ground state, and the guest material 13 returns to the ground state. 2 enters an excited state. Note that the rate constant k of the Förster mechanism is... h*→g This is shown in equation (1). .

[0086]

number

[0087] In equation (1), ν represents the frequency, and f' h (ν) is a standard for host material 131. Emission spectra (when discussing energy transfer from singlet excited states, fluorescence spectra are used) When discussing energy transfer from triplet excited states, the phosphorescent spectrum is used. ε g(ν) represents the molar extinction coefficient of guest material 132, N represents Avogadro's number, and n represents the refractive index of the medium, and R represents the intermolecular distance between the host material 131 and the guest material 132. τ represents the measured lifetime of the excited state (fluorescence lifetime or phosphorescence lifetime), and c represents the speed of light. φ is the emission quantum yield (or fluorescence quantum yield when discussing energy transfer from singlet excited states). When discussing energy transfer from triplet excited states, the phosphorescence quantum yield is expressed as K 2 teeth, A coefficient representing the orientation of the transition dipole moments of the host material 131 and the guest material 132 (from 0) 4) In the case of random orientation, K 2 = 2 / 3

[0088] Dexter Mechanism In the Dexter mechanism, the host material 131 and the guest material 132 come into contact with each other to create an orbital overlap. Approaching within effective contact distance, electrons from the excited host material 131 and the ground state guest material 13 Energy transfer occurs through the exchange of electrons with 2. Note that the rate constant k of the Dexter mechanism h*→g This is shown in equation (2).

[0089]

number

[0090] In equation (2), h is Planck's constant, and K is a constant with the dimension of energy. Here, ν represents the frequency, and f' h (ν) is the normalized luminescence of the host material 131. Pectol (When discussing energy transfer from singlet excited states, use fluorescence spectra, triplet When discussing energy transfer from an excited state, the phosphorescent spectrum is represented, and ε' g (ν) The normalized absorption spectrum of guest material 132 is shown, and L represents the effective molecular radius. R represents the intermolecular distance between the host material 131 and the guest material 132.

[0091] Here, the energy transfer efficiency φ from the host material 131 to the guest material 132 is present. ET is, number It is expressed by equation (3). k r This is the luminescence process of the host material 131 (energy from singlet excited state When discussing energy transfer, use fluorescence; when discussing energy transfer from triplet excited states, use phosphorus. This represents the velocity constant of light, k n This is related to the non-luminescent processes (thermal deactivation and intersystem crossing) of the host material 131. The rate constant is represented, and τ represents the measured lifetime of the excited state of the host material 131.

[0092]

number

[0093] From equation (3), the energy transfer efficiency φ ET In order to increase the speed of energy transfer degree constant k h*→g Increase the other competing rate constants k r +k n (=1 / τ) You'll understand that it's better if it's smaller.

[0094] ≪A concept for enhancing energy transfer≫ First, let's consider energy transfer via the Förster mechanism. Substitute equation (1) into equation (3). By inputting, τ can be eliminated. Therefore, in the case of the Förster mechanism, Ghee transport efficiency φ ET This does not depend on the lifetime τ of the excited state of the host material 131. Also, energy Energy transfer efficiency φ ET This discusses the luminescence quantum yield φ (energy transfer from singlet excited states). Therefore, a higher fluorescence quantum yield is preferable. Generally, triplet excitation of organic compounds The emission quantum yield from the initial state is very low at room temperature. Therefore, the host material 131 is three In the case of a multiplet excited state, the energy transfer process by the Förster mechanism can be ignored, and We only need to consider the case where material 131 is in a singlet excited state.

[0095] Furthermore, the emission spectrum of the host material 131 (discussing energy transfer from the singlet excited state) If you want to compare the fluorescence spectrum and the absorption spectrum of guest material 132 (from the singlet ground state), It is preferable that there is a large overlap with the absorption corresponding to the transition to the singlet excited state. A higher molar extinction coefficient for the guest material 132 is also preferable. This is because the host material 131 The emission spectrum and the absorption band that appears at the longest wavelength end of guest material 132 overlap. It tastes good. Furthermore, the direct transition from the singlet ground state to the triplet excited state in guest material 132 is... Since transfer is prohibited, the molar absorption rate involving the triplet excited state in guest material 132 The number is negligible. From this, the three guest material 132 by the Förster mechanism The energy transfer process to the doublet excited state can be ignored, and the guest material 132 reaches the singlet excited state. Only the energy transfer process of H needs to be considered. That is, in the Förster mechanism, H Energy from the singlet excited state of main material 131 to the singlet excited state of guest material 132 We just need to consider the process of movement.

[0096] Next, let's consider energy transfer via the Dexter mechanism. According to equation (2), the velocity constant k h*→g To increase the size, the emission spectrum of the host material 131 (from the singlet excited state) When discussing energy transfer, use fluorescence spectra and the absorption spectra of guest material 132. The greater the overlap with the absorption corresponding to the transition from the singlet ground state to the singlet excited state, the better. It can be seen that... Therefore, optimizing the energy transfer efficiency is important for the luminescence of the host material 131. The spectrum and the absorption band that appears at the longest wavelength end of guest material 132 overlap. It will be realized.

[0097] Furthermore, substituting equation (2) into equation (3) reveals the energy transfer in the Dexter mechanism. Efficiency φ ET It can be seen that it depends on τ. The Dexter mechanism is based on electron exchange. Since this is a ghee transfer process, it is a singlet excited state from the host material 131 to the guest material 132. Similar to energy transfer to the doublet excited state, from the triplet excited state of the host material 131, Energy transfer also occurs to the triplet excited state of material 132.

[0098] In one embodiment of the present invention, the guest material 132 is a fluorescent material, therefore It is preferable that the energy transfer efficiency to the triplet excited state of material 132 is low. Energy transfer effect based on the Dexter mechanism from host material 131 to guest material 132 A low rate is preferable, and the Förster mechanism from the host material 131 to the guest material 132. High energy transfer efficiency based on this is preferable.

[0099] As already mentioned, the energy transfer efficiency in the Förster mechanism is as follows: It does not depend on the lifetime τ of the excited state 1. On the other hand, the energy transfer efficiency in the Dexter mechanism This depends on the excitation lifetime τ of the host material 131. Therefore, the energy in the Dexter mechanism To reduce energy transfer efficiency, it is preferable that the excitation lifetime τ of the host material 131 be short. It's nice.

[0100] Furthermore, similar to the energy transfer from the host material 131 to the guest material 132, the excited complex The energy transfer process from to guest material 132 is also related to the Förster mechanism and the Deck Energy transfer occurs through both mechanisms in the star mechanism.

[0101] Therefore, one aspect of the present invention provides an energy transfer mechanism that can efficiently transfer energy to the guest material 132. Organic compound 131, a combination that forms an excited complex having the function of an energy donor. The present invention provides a light-emitting element having _1 and organic compound 131_2 as the host material 131. The excited complexes formed by organic compound 131_1 and organic compound 131_2 are singlet excited It has the characteristic that the energy level and the triplet excitation energy level are in close proximity. Therefore, the transition from triplet excitons to singlet excitons generated in the light-emitting layer 130 (reverse intersystem crossover) This difference is likely to occur. Therefore, the singlet exciton generation efficiency in the light-emitting layer 130 is increased. Furthermore, it is possible to obtain an energy acceptor from the singlet excited state of the excited complex. In order to facilitate energy transfer to the singlet excited state of guest material 132, The emission spectrum of the complex and the longest wavelength (lowest energy) emission spectrum of guest material 132. It is preferable that the absorption band and the singlet excited state of guest material 132 overlap. This can increase the efficiency of production.

[0102] Furthermore, among the luminescence exhibited by the excited complex, the fluorescence lifetime of the thermally activated delayed fluorescence component is short. Preferably, the duration is 10 ns to 50 μs, more preferably 10 ns to 3 It is less than 0 μs.

[0103] Furthermore, the proportion of thermally activated delayed fluorescence components in the luminescence exhibited by the excited complex is high. Preferred. Specifically, the proportion of the luminescence exhibited by the excited complex that is accounted for by the thermally activated delayed fluorescence component. The blend is preferably 5% or more, more preferably 10% or more.

[0104] <Material> Next, the details of the components of a light-emitting element according to one aspect of the present invention will be described below.

[0105] ≪Luminous layer≫ The materials that can be used for the light-emitting layer 130 are described below.

[0106] In the light-emitting layer 130, the host material 131 is the most abundant by weight, followed by the guest material 132 The (fluorescent material) is dispersed in the host material 131. Host material 131 of the light-emitting layer 130 ( The S1 levels of organic compounds 131_1 and 131_2 are guest levels of the luminescent layer 130. It is preferable that the level is higher than the S1 level of material 132 (fluorescent material). Also, the level of the luminescent layer 130 is The T1 level of material 131 (organic compound 131_1 and organic compound 131_2) is luminescent. It is preferable that the T1 level is higher than that of the guest material 132 (fluorescent material) in layer 130.

[0107] Organic compound 131_1, on its own, achieves triplet excitation energy through singlet excitation via reverse intersystem crossing. Preferably, it has the function of converting energy, and exhibits thermally activated delayed fluorescence at room temperature. It is preferable that the triplet excitation energy can be converted into singlet excitation energy. Examples of materials include thermally activated delayed fluorescence materials. If it is made up of the following materials, for example, the following materials can be used.

[0108] First, there are fullerenes and their derivatives, acridine derivatives such as proflavin, and eosin. It can be produced. Also, magnesium (Mg), zinc (Zn), cadmium (Cd), tin (S) n) Metals containing platinum (Pt), indium (In), or palladium (Pd), etc. Examples include metal-containing porphyrins. For example, protoporph Fluorine-tin fluoride complex (SnF2(Proto IX)), mesoporphyrin-fluoride Tin complex (SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (Sn F2 (Hemato IX), coproporphyrin tetramethyl ester - tin fluoride Complex (SnF2(Copro III-4Me)), octaethylporphyrin-fluoride Tin complex (SnF2(OEP)), Ethioporphyrin-tin fluoride complex (SnF2(E Examples include tio I)) and octaethylporphyrin-platinum chloride complex (PtCl2OEP). It can be done.

[0109] [ka]

[0110] Furthermore, as a thermally activated delayed fluorescence material composed of one type of material, a π-electron-rich complex atom is an example. Heterocyclic compounds having a fragrance group skeleton and a π-electron-deficient heteroaromatic skeleton can also be used. Specifically, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindoro[ 2,3-a]carbazole-11-yl)-1,3,5-triazine (abbreviation: PIC-T RZ), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-3-yl) Luvazole-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated) Name: PCCzPTzn), 2-[4-(10H-phenoxazine-10-yl)phenyl ]-4,6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3-[4 -(5-phenyl-5,10-dihydrophenazine-10-yl)phenyl]-4,5- Diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-di Methyl-9H-acridin-10-yl)-9H-xanthene-9-one (abbreviation: ACR) XTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl] Sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10'H-spiro[a Examples include clidine-9,9'-anthracene]-10'-one (abbreviated as ACRSA). The heterocyclic compound comprises a π-electron-rich heteroaromatic skeleton and a π-electron-deficient heteroaromatic skeleton. Because it possesses high electron transport and hole transport properties, it is preferable. In particular, π-electron-deficient complex aromas are desirable. Among the fragrant family skeletons, the diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), Furthermore, the triazine skeleton is preferred because it is stable and reliable. Also, π-electron-rich complex Among aromatic skeletons, the acridine skeleton, phenoxazine skeleton, phenothiazine skeleton, and fura The ¹ⁿ skeleton, thiophene skeleton, and pyrrole skeleton are stable and reliable, therefore, the said skeletons It is preferable to have one or more selected from among them. The indole skeleton and carbazole skeleton are preferred, and 3-(9-phenyl-9H- A carbazole-3-yl)-9H-carbazole skeleton is particularly preferred. A substance in which a superfluous heteroaromatic skeleton and a π-electron-deficient heteroaromatic skeleton are directly bonded is π-electron-rich. Both the donor properties of the complex aromatic skeleton and the acceptor properties of the π-electron-deficient complex aromatic skeleton are strong. Because the difference between the singlet excitation energy level and the triplet excitation energy level becomes smaller, it is particularly favorable. It seems so.

[0111] [ka]

[0112] Furthermore, organic compound 131_1 undergoes singlet excitation of triplet excitation energy via reverse intersystem crossing. It only needs to have the function of converting into electromotive force, and does not need to have the function of exhibiting thermally activated delayed fluorescence. It may also be the case that the organic compound 131_1 is a π-electron-rich heteroaromatic skeleton or aromatic At least one of the group amine skeletons and a π-electron-deficient heteroaromatic skeleton are connected to an m-phenylene group. or a structure that is bonded via a structure having at least one o-phenylene group This is preferable. Alternatively, at least one of the m-phenylene group or o-phenylene group It is preferable to have a structure that is bonded via an arylene group, and the arylene group is A phenylene group is even more preferable. In this way, the T1 junction of organic compound 131_1 is achieved. The position can be raised. In this case as well, the π-electron-deficient complex aromatic skeleton , diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), or triazine It is preferable that it has a skeleton. Furthermore, the π-electron-rich heteroaromatic skeleton is an acridine skeleton, Phenoxazine skeleton, phenothiazine skeleton, furan skeleton, thiophene skeleton, and pyrrole It is preferable to have one or more selected from the skeleton. The dibenzofuran skeleton is used for the skeletal structure, and the dibenzothiophene skeleton is used for the thiophene skeleton. Each of these is preferable. In addition, as for the pyrrole skeleton, the indole skeleton and the carbazole skeleton are preferred. Preferably, 3-(9-phenyl-9H-carbazol-3-yl)-9H-carbazol A luminous skeleton is particularly preferred. In addition, as an aromatic amine skeleton, a so-called luminous skeleton that does not have an NH bond is preferred. A tertiary amine is preferred, and a triarylamine skeleton is particularly preferred. The aryl group in the skeleton is a substituted or unsubstituted aryl group with 6 to 13 carbon atoms forming the ring. A fluorenyl group is preferred, and examples include a phenyl group, naphthyl group, and fluorenyl group.

[0113] Examples of the above aromatic amine skeletons and π-electron-rich heteroaromatic skeletons include the following general examples. The framework is represented by formulas (101) to (117). Note that general formulas (113) to (11) 6) In this case, X represents either an oxygen atom or a sulfur atom.

[0114] [ka]

[0115] Furthermore, an example of the above-mentioned π-electron-deficient complex aromatic skeleton is the following general formula (201) to This is the skeleton represented by (218).

[0116] [ka]

[0117] Hole-transporting skeletons (specifically, π-electron-rich heteroaromatic skeletons or aromatic amines) (at least one of the skeletons) and a skeleton with electron transport properties (specifically, a π-electron-deficient complex aromatic A group skeleton and a bond having at least one m-phenylene group or o-phenylene group. Bonding via a group, or at least one of the m-phenylene group or o-phenylene group When bonding occurs via a bonding group having an arylene group, an example of such bonding group is: The skeleton is represented by the following general formulas (301) to (314). Note that the above arylene group Examples include phenylene skeleton, biphenyldiyl skeleton, naphthalene diyl skeleton, and fluorene. Examples include the gyle skeleton and the phenantrenzyle skeleton.

[0118] [ka]

[0119] The above-mentioned aromatic amine skeleton (specifically, the triarylamine skeleton), π-electron-rich complex Aromatic skeletons (specifically acridine skeleton, phenoxazine skeleton, phenothiazine skeleton, f Rings having a rane skeleton, thiophene skeleton, or pyrrole skeleton, π-electron-deficient heteroaromatic skeleton ( Specifically, a ring having a diazine skeleton or a triazine skeleton, or the general formula (1 01) to (117), general formulas (201) to (218), and general formulas (301) to ( 314) may have substituents. Such substituents may have 1 to 6 carbon atoms. Alkyl groups, cycloalkyl groups with 3 to 6 carbon atoms, or groups with 6 to 12 carbon atoms. A substituted or unsubstituted aryl group can also be selected as a substituent. (1 to 1 carbon atom) Examples of C6 alkyl groups include methyl, ethyl, propyl, and isopropyl groups. Examples include pyr group, butyl group, isobutyl group, tert-butyl group, n-hexyl group, etc. This can be done. In addition, as a cycloalkyl group having 3 to 6 carbon atoms, specifically, Examples include cyclopropyl group, cyclobutyl group, cyclopentyl group, and cyclohexyl group. This can be done. In addition, as aryl groups having 6 to 12 carbon atoms, phenyl groups, naphthium groups can be used. Specific examples include the 14-unit group and the biphenyl group. They may combine to form a ring. An example of this is, for example, in a fluorene skeleton. If the carbon atom at position 9 has two phenyl groups as substituents, these phenyl groups bond together. This can lead to the formation of a spirofluorene skeleton. In this case, it is advantageous in terms of ease of synthesis and the price of raw materials.

[0120] Furthermore, Ar represents an arylene group having 6 to 13 carbon atoms, and this arylene group is substituted. They may have groups, and these substituents may bond to each other to form a ring. For example, the carbon at position 9 of the fluorenyl group has two phenyl groups as substituents, In cases where the phenyl groups bond together to form a spirofluorene skeleton. Examples include arylene groups having 6 to 13 carbon atoms, such as phenylene groups and naphthium groups. Specific examples include the ylene group, biphenylene group, and fluoranyl group. Furthermore, if the arylene group has substituents, such substituents may be C1 to C2 6 alkyl groups, cycloalkyl groups with 3 to 6 carbon atoms, or groups with 6 to 6 carbon atoms Twelve aryl groups can also be selected as substituents. Alky groups with 1 to 6 carbon atoms. Specifically, the propyl groups include methyl, ethyl, propyl, isopropyl, and butyl groups. Examples include isobutyl groups, tert-butyl groups, and n-hexyl groups. Specifically, examples of cycloalkyl groups having 3 to 6 carbon atoms include cyclopropyl groups, cyclopropyl groups, and Examples include chlorobutyl groups, cyclopentyl groups, and cyclohexyl groups. Examples of aryl groups having 6 to 12 carbon atoms include the phenyl group, naphthyl group, and biphenyl group. These are some specific examples.

[0121] Furthermore, the arylene group represented by Ar is, for example, shown in the following structural formulas (Ar-1) to (Ar- The group represented in 18) can be applied. Note that the group that can be used as Ar is These are not the only ones.

[0122] [ka]

[0123] Also, R 1 and R 2 Each of these independently consists of hydrogen, an alkyl group having 1 to 6 carbon atoms, A cycloalkyl group having 3 to 6 carbon atoms, or a substitution of 6 to 13 carbon atoms. represents any unsubstituted aryl group. C1 to C6 alkyl groups include ``. Specifically, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group Examples include tert-butyl groups and n-hexyl groups. Also, groups with 3 or more carbon atoms. Examples of cycloalkyl groups with 6 carbon atoms include cyclopropyl and cyclobutyl groups. Examples include cyclopentyl groups and cyclohexyl groups. Also, groups with 6 or more carbon atoms. Examples of aryl groups with 13 carbon atoms include phenyl, naphthyl, biphenyl, and fluorenyl groups. The aryl group and phenyl group mentioned above are examples of this. The substituents may have substituents, and these substituents may be bonded to each other to form a ring. The bases include alkyl groups with 1 to 6 carbon atoms and cycloalkyl groups with 3 to 6 carbon atoms. A C6 or C6 to C12 aryl group can also be selected as a substituent. Specifically, alkyl groups having 1 to 6 carbon atoms include methyl, ethyl, and propyl groups. Isopropyl group, butyl group, isobutyl group, tert-butyl group, n-hexyl group Examples include the following. Furthermore, cycloalkyl groups having 3 to 6 carbon atoms include... In terms of composition, it consists of cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl groups. Examples include phenyl Examples of specific groups include the 14-36 group, naphthyl group, and biphenyl group.

[0124] Also, R 1 and R 2 The alkyl or aryl group represented by the following structural formula is, for example, ( Groups represented by R-1) to (R-29) can be applied. Note that alkyl groups and These are not the only groups that can be used as aryl groups.

[0125] [ka]

[0126] Also, general formulas (101) to (117), general formulas (201) to (218), general formula ( 301) to (314), and Ar, R 1 and R 2 The substituents that can be present are, for example, If, then, the alkyl group or aryl group represented by the above structural formulas (R-1) to (R-24) is suitable It can be used. The groups that can be used as alkyl or aryl groups are: These are not the only ones.

[0127] In the luminescent layer 130, there are no particular limitations on the guest material 132, but anthracene is also acceptable. Derivatives, tetracene derivatives, chrysene derivatives, phenanthrene derivatives, pyrene derivatives, Lylene derivatives, stilbene derivatives, acridone derivatives, coumarin derivatives, phenoxazine Derivatives, phenothiazine derivatives, etc., are preferred, and for example, the following materials can be used. .

[0128] Specifically, 5,6-bis[4-(10-phenyl-9-antryl)phenyl]-2 ,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl -9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2) BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluorine) [Len-9-yl]phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn) N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H -Fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMem FLPAPrn), N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl) )phenyl]-N,N'-bis(4-tert-butylphenyl)pyrene-1,6-dia Min (abbreviation: 1,6tBu-FLPAPrn), N,N'-diphenyl-N,N'-bis [4-(9-phenyl-9H-fluoren-9-yl)phenyl]-3,8-dicyclophenyl Xylpyrene-1,6-diamine (abbreviation: ch-1,6FLPAPrn), N,N'-bi Su[4-(9H-carbazole-9-yl)phenyl]-N,N'-diphenylstilbe n-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazole-9-yl) -4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA) , 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-ant) Lyl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4- (10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine (abbreviated) Name: PCAPA), Perylene, 2,5,8,11-Tetra(tert-butyl)perylene (Abbreviation: TBP), 4-(10-phenyl-9-antryl)-4'-(9-phenyl- 9H-carbazole-3-yl)triphenylamine (abbreviation: PCBAPA), N,N' '-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene) Bis[N,N',N'-triphenyl-1,4-phenylenediamine] (abbreviation: DPAB) PA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl) [enyl]-9H-carbazole-3-amine (abbreviation: 2PCAPPA), N-[4-(9 ,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1 ,4-phenylenediamine (abbreviation: 2DPAPPA), N,N,N',N',N'',N '',N''',N'''-Octaphenyldibenzo[g,p]chrysene-2,7,10 ,15-tetraamine (abbreviation: DBC1), coumarin 30, N-(9,10-diphenyl -2-anthryl)-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2 PCAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-ant [Lyl]-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCABPh) A) N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl -1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(1,1 '-biphenyl-2-yl)-2-anthryl]-N,N',N'-triphenyl-1, 4-phenylenediamine (abbreviation: 2DPABPhA), 9,10-bis(1,1'-bis( (phenyl-2-yl)-N-[4-(9H-carbazole-9-yl)phenyl]-N-f Phenylanthracene-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenyl Luanthracene-9-amine (abbreviation: DPhAPhA), Coumarin 6, Coumarin 545T N,N'-diphenylquinacridone (abbreviation: DPQd), rubren, 2,8-di-te rt-butyl-5,11-bis(4-tert-butylphenyl)-6,12-diphenyl Lutetracene (abbreviation: TBRb), Nile Red, 5,12-bis(1,1'-biphenyl Lu-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), 2-(2-{2- [4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-yly Dene)propanedinitrile (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3 ,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl ]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N ',N'-Tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-meth (p) acenaphtho[1,2-a]fluorantene-3,10-diamine (abbreviation: p -mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethicone)] Ru-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl )Ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI) , 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3, 6,7-Tetrahydro-1H,5H-Benzo[ij]quinoridine-9-yl)ethenyl -4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2, 6-Bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-i (Liden)propanedinitrile (abbreviation: BisDCM), 2-{2,6-bis[2-(8- Methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H -Benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene} Ropanedinitrile (abbreviation: BisDCJ™), 5,10,15,20-tetraphenyl Bisbenzo[5,6]indeno[1,2,3-cd:1',2',3'-lm]perylene These are some examples.

[0129] As mentioned above, from host material 131 (or excited complex) to guest material 132 The energy transfer efficiency based on the Dexter mechanism is preferably low. The rate constant is inversely proportional to the exponential function of the distance between two molecules. Therefore, the distance between two molecules is approximately Below 1 nm, the Dexter mechanism is dominant, while above approximately 1 nm, the Förster mechanism is dominant. This becomes dominant. Therefore, to reduce the energy transfer efficiency in the Dexter mechanism... To achieve this, it is preferable to increase the distance between the host material 131 and the guest material 132. Generally, it is preferably 0.7 nm or larger, more preferably 0.9 nm or larger, and even more preferably It is 1 nm or more. From this perspective, the guest material 132 is close to the host material 131. It is preferable to have substituents that inhibit fusion, and aliphatic hydrocarbons are preferred as such substituents. More preferably, an alkyl group, and even more preferably a branched alkyl group. Specifically, guest material 132 has at least two alkyl groups having 2 or more carbon atoms. This is preferable. Alternatively, the guest material 132 is an aluminum alloy having 3 to 10 carbon atoms and branching. It is preferable that it has at least two kill groups. Alternatively, guest material 132 has a carbon number Preferably, it has at least two cycloalkyl groups with a value between 3 and 10.

[0130] Organic compound 131_2 is a combination that can form an excited complex with organic compound 131_1. Specifically, this includes zinc and aluminum-based metal complexes, as well as oxadiazole derivatives. , triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzoquinone Xaline derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, pyrimidine derivatives triazine derivatives, pyridine derivatives, bipyridine derivatives, phenanthroline derivatives, etc. Examples include aromatic amines and carbazole derivatives. In this case, the emission of light from the excited complex formed by organic compound 131_1 and organic compound 131_2. The peak corresponds to the longest wavelength (lowest energy) absorption band of guest material 132 (fluorescent material). Overlapping are organic compound 131_1, organic compound 131_2, and guest material 132 It is preferable to select a (fluorescent material). This dramatically improves the luminescence efficiency. It can be used as an element.

[0131] Furthermore, the following hole transport materials and electron transport materials are used as organic compound 131_2. It can be used.

[0132] As a hole-transporting material, a material with higher hole transport capabilities than electron transport can be used, ×10 -6 cm 2 It is preferable that the material has a hole mobility of / Vs or greater. Specifically This uses aromatic amines, carbazole derivatives, aromatic hydrocarbons, stilbene derivatives, etc. This is possible. Furthermore, the hole-transporting material may be a polymer compound.

[0133] Examples of materials with high hole transport capabilities include, 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-diphenylaminophenic acid) Examples include [Lu]-N-phenylaminobenzene (abbreviation: DPA3B), etc.

[0134] Furthermore, as a carbazole derivative, specifically, 3-[N-(4-diphenylamino Phenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA1) ), 3,6-bis[N-(4-diphenylaminophenyl)-N-phenylamino]-9 -Phenylcarbazole (abbreviation: PCzDPA2), 3,6-bis[N-(4-diphenyl (Aminophenyl)-N-(1-naphthyl)amino]-9-phenylcarbazole (abbreviation) :PCzTPN2), 3-[N-(9-phenylcarbazole-3-yl)-N-phenyl Luamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N- (9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarb Zol (abbreviation: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcate Luvazole-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1) Examples include:

[0135] In addition, other carbazole derivatives include 4,4'-di(N-carbazolyl)bife Nyl (abbreviated as CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]bene Zen (abbreviation: TCPB), 9-[4-(10-phenyl-9-antryl)phenyl]- 9H-carbazole (abbreviation: CzPA), 1,4-bis[4-(N-carbazolyl)phen [Nyl]-2,3,5,6-tetraphenylbenzene, etc., can be used.

[0136] 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 Tracene (abbreviation: DPPA), 2-tert-butyl-9,10-bis(4-phenyl Enyl anthracene (abbreviation: t-BuDBA), 9,10-di(2-naphthyl)ant Helical (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) Chil)anthracene, 9,9'-bianthryl, 10,10'-diphenyl-9,9'- Biantryl, 10,10'-bis(2-phenylphenyl)-9,9'-biantryl ,10,10'-bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9' -Biantril, Anthracene, Tetracene, Rubren, Perylene, 2, 5, 8, 11- Examples include tetra(tert-butyl)perylene. In addition, pentacene, coro Nen and other similar materials can also be used. In this way, 1 × 10 -6 cm 2 Hole mobility of / Vs or greater It is more preferable to use aromatic hydrocarbons having 14 to 42 carbon atoms.

[0137] Furthermore, aromatic hydrocarbons may have a vinyl skeleton. Examples of group hydrocarbons include 4,4'-bis(2,2-diphenylvinyl)biphenyl (Abbreviation: DPVBi), 9,10-bis[4-(2,2-diphenylvinyl)phenyl] Examples include anthracene (abbreviated as DPVPA).

[0138] Also, poly(N-vinylcarbazole) (abbreviation: PVK) and poly(4-vinyltriphen 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 High molecular weight compounds such as (phenyl)benzidine (abbreviated as Poly-TPD) can also be used. can.

[0139] Furthermore, materials with high hole transport capabilities include, for example, 4,4'-bis[N-(1-naphthyl )-N-phenylamino]biphenyl (abbreviation: NPB or α-NPD) or N,N'-bi Su(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4 '-diamine (abbreviation: TPD), 4,4',4''-tris(carbazole-9-yl) Triphenylamine (abbreviation: TCTA), 4,4',4''-tris[N-(1-naphthyl [Lu)-N-phenylamino]triphenylamine (abbreviation: 1'-TNATA), 4,4' ,4''-Tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA) ), 4,4',4''-Tris[N-(3-methylphenyl)-N-phenylamino] Riphenylamine (abbreviation: MTDATA), 4,4'-bis[N-(spiro-9,9'- Bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4- Phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: B) PAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenyl Luamine (abbreviation: mBPAFLP), N-(9,9-dimethyl-9H-fluorene-2- Il)-N-{9,9-dimethyl-2-[N'-phenyl-N'-(9,9-dimethyl- 9H-Fluoren-2-yl)amino]-9H-Fluoren-7-yl}phenylamine (Abbreviation: DFLADFL), N-(9,9-dimethyl-2-diphenylamino-9H-) Luoren-7-yl)diphenylamine (abbreviation: DPNF), 2-[N-(4-diphenyl [N-phenylamino]spiro-9,9'-bifluorene (abbreviation: D PASF), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl) Diphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-diphenylamine) Phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP) ), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl) Riphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-( 9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBNB) B) 4-phenyldiphenyl-(9-phenyl-9H-carbazole-3-yl)amine N (abbreviation: PCA1BP), N,N'-bis(9-phenylcarbazole-3-yl)- N,N'-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N,N',N ''-Triphenyl-N,N',N''-Tris(9-phenylcarbazole-3-yl) )Benzene-1,3,5-triamine (abbreviation: PCA3B), N-(4-biphenyl)- N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-carb Zole-3-amine (abbreviation: PCBiF), N-(1,1'-biphenyl-4-yl)- N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl Tyl-9H-fluoren-2-amine (abbreviation: PCBBiF), 9,9-dimethyl-N- Phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]flu Oren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl- 9H-carbazole-3-yl)phenyl]spiro-9,9'-bifluoren-2-amine N (abbreviation: PCBASF), 2-[N-(9-phenylcarbazole-3-yl)-N- Phenylamino]spiro-9,9'-bifluorene (abbreviation: PCASF), 2,7-bis [N-(4-diphenylaminophenyl)-N-phenylamino]-spiro-9,9'- Bifluoren (abbreviation: DPA2SF), N-[4-(9H-carbazole-9-yl) [phenyl]-N-(4-phenyl)phenylaniline (abbreviation: YGA1BP), N,N'- Bis[4-(carbazole-9-yl)phenyl]-N,N'-diphenyl-9,9-di Aromatic amine compounds such as methylfluorene-2,7-diamine (abbreviation: YGA2F), etc. It can also be used. Furthermore, 3-[4-(1-naphthyl)-phenyl]-9-phenyl -9H-carbazole (abbreviation: PCPN), 3-[4-(9-phenanthril)-pheni [Lu]-9-phenyl-9H-carbazole (abbreviation: PCPPn), 3,3'-bis(9- Phenyl-9H-carbazole (abbreviation: PCCP), 1,3-bis(N-carbazolyl) )Benzene (abbreviation: mCP), 3,6-bis(3,5-diphenylphenyl)-9-phenyl Nilcarbazole (abbreviation: CzTP), 3,6-di(9H-carbazole-9-yl)- 9-phenyl-9H-carbazole (abbreviation: PhCzGI), 2,8-di(9H-carbazole) Zole-9-yl)-dibenzothiophene (abbreviation: Cz2DBT), 4-{3-[3-( 9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviated) Name: mmDBFFLBi-II), 4,4',4''-(benzene-1,3,5-torii 1,3,5-tri(dibenzofuran) (abbreviation: DBF3P-II), 1,3,5-tri(dibenzofuran) Thiophen-4-yl)-benzene (abbreviation: DBT3P-II), 2,8-diphenyl- 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophen (Abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluorene-9) -yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), 4-[3-(triphenylene-2-yl)phenyl]dibenzothiophene (abbreviation: mDB) Amine compounds such as TPTp-II, carbazole compounds, thiophene compounds, and furan compounds. Compounds, fluorene compounds, triphenylene compounds, phenanthrene compounds, etc. are used. This can be done. The substances described here are mainly 1 × 10 -6 cm 2 Having a hole mobility of / Vs or greater It is a substance that transports holes more efficiently than electrons. You may use it.

[0140] As electron-transporting materials, materials with higher electron transport capabilities than holes can be used, ×10 -6 cm 2 It is preferable that the material has an electron mobility of / Vs or higher. Examples of easily absorbed materials (materials with electron transport properties) include nitrogen-containing heteroaromatic compounds. π-electron-deficient heteroaromatic compounds and metal complexes can be used. Specifically, Norine ligand, benzoquinoline ligand, oxazole ligand, or thiazole ligand Metal complexes having oxadiazole derivatives, triazole derivatives, phenanthroline derivatives Examples include conductors, pyridine derivatives, bipyridine derivatives, and pyrimidine derivatives.

[0141] For example, tris(8-quinolinolato)aluminum(III) (abbreviation: Alq), tri (4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq3), (10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq2) ), bis(2-methyl-8-quinolinolate)(4-phenylphenolate)aluminum ( III) (Abbreviation: BAlq), Bis(8-quinolinolato)zinc(II) (Abbreviation: Znq) These include metal complexes having a quinoline skeleton or a benzoquinoline skeleton. Bis[2-(2-benzoxazolyl)phenolate]zinc(II) (abbreviation: ZnPBO) , bis[2-(2-benzothiazolyl)phenolate]zinc(II) (abbreviation: ZnBTZ) Metal complexes having oxazole-based or thiazole-based ligands can also be used. Furthermore, in addition to metal complexes, there are also 2-(4-biphenylyl)-5-(4-tert-butyl Phenyl)-1,3,4-oxadiazole (abbreviation: PBD) and 1,3-bis[5-( p-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (Abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazole-2 -yl)phenyl]-9H-carbazole (abbreviation: CO11), 3-(4-biphenylyl )-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (Abbreviation: TAZ), 9-[4-(4,5-diphenyl-4H-1,2,4-triazole) -3-yl)phenyl]-9H-carbazole (abbreviation: CzTAZ1), 2,2',2' -(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzoimidazo (Abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1 -Phenyl-1H-benzoimidazole (abbreviation: mDBTBIm-II), basofenan Trolin (abbreviation: BPhen), vasocuproine (abbreviation: BCP), 2,9-bis(na Phthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NB) Heterocyclic compounds such as Phen, and 2-[3-(dibenzothiophen-4-yl)phen [Lu]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3' -(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoki Sarin (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazole-9 -yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBP) DBq), 2-[4-(3,6-diphenyl-9H-carbazole-9-yl)phenyl ]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(di Benzothiophene-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7m) DBTPDBq-II), and 6-[3-(dibenzothiophen-4-yl)phenyl ]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 2-[3-( 3,9'-bi-9H-carbazole-9-yl)phenyl]dibenzo[f,h]quinoxa Phosphate (abbreviation: 2mCzCzPDBq), 4,6-bis[3-(phenanthrene-9-yl) )phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-di [benzothienyl]phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4, 6-Bis[3-(9H-carbazole-9-yl)phenyl]pyrimidine (abbreviation: 4,6) Heterocyclic compounds having a diazine skeleton such as mCzP2Pm, and PCCzPTzn, etc. Heterocyclic compounds having a triazine skeleton, or 3,5-bis[3-(9H-carbazole-9 -yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3 Compounds with a pyridine skeleton, such as pyridyl(phenyl)benzene (abbreviation: TmPyPB). Cyclic compound, 4,4'-bis(5-methylbenzoxazole-2-yl)stilbene ( Heteroaromatic compounds such as (abbreviated as BzOs) can also be used. The above-mentioned heterocyclic compounds Among them, the diazine (pyrimidine, pyrazine, pyridazine) skeleton, or the pyridine skeleton The heterocyclic compounds having this skeleton are stable, reliable, and therefore preferable. The cyclic compounds exhibit high electron transport properties and contribute to reducing the driving voltage. Furthermore, poly(2,5-p) Lysine diyl (abbreviation: PPy), poly[(9,9-dihexylfluorene-2,7-di (Il)-co-(pyridine-3,5-diyl) (abbreviation: PF-Py), poly[(9,9 -Dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6' Polymer compounds such as -diyl) (abbreviation: PF-BPy) can also be used. The substances mentioned above are mainly 1 × 10 -6 cm 2 It is a substance with an electron mobility of / Vs or higher. Furthermore, any material that has higher electron transport capabilities than holes may be used in addition to those mentioned above. .

[0142] The light-emitting layer 130 can also be composed of two or more layers. For example, the first When the first light-emitting layer and the second light-emitting layer are stacked in order from the hole transport layer side to form the light-emitting layer 130, A material having hole transport properties is used as the host material for the first light-emitting layer, and the host material for the second light-emitting layer One such configuration involves using materials that possess electron-transporting properties.

[0143] Furthermore, in the light-emitting layer 130, materials other than the host material 131 and the guest material 132 are used. It's okay to have it.

[0144] ≪Hole Injection Layer≫ The hole injection layer 111 is a hole injection layer that receives 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, for example, transition metal oxides, f It is formed by tarocyanine derivatives or aromatic amines, etc. Transition metal oxides and For example, molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide Examples include manganese oxides. Phthalocyanine derivatives include phthalocyanine and Examples include metal phthalocyanines. Aromatic amines include benzidine derivatives and phenyl Examples include lendiamine derivatives. Polymer compounds such as polythiophene and polyaniline. Substances can also be used, for example, self-doped polythiophene such as poly(ethylenedi Typical examples include oxythiophene / poly(styrene sulfonic acid).

[0145] As the hole injection layer 111, a hole transport material and a material that exhibits electron-accepting properties in relation to it are combined. A layer containing composite material can also be used. Alternatively, a layer containing an electron-accepting material and a positive A lamination of layers containing pore-transporting material may also be used. Between these materials, a steady state or electrical current may be maintained. Charge transfer is possible in the presence of an electron barrier. Examples of materials exhibiting electron-accepting properties include Kinojimeta. Organic acceptors such as chloranil derivatives and hexaazatriphenylene derivatives We can list the following: 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-Hexazatriphenylene (abbreviated) These are compounds that have electron-withdrawing groups (halogen groups or cyano groups), such as HAT-CN. Furthermore, transition metal oxides, such as oxides of Group 4 to Group 8 metals, can be used. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, acid These include tungsten oxide, manganese oxide, and rhenium oxide. Among these, molybdenum oxide is particularly toxic to the atmosphere. Among them, it is preferable because it is stable, has low hygroscopicity, and is easy to handle.

[0146] As a hole-transporting material, a material with higher hole transport capabilities than electron transport can be used, ×10 -6 cm 2 It is preferable that the material has a hole mobility of / Vs or greater. Specifically Aromatic amines and calcine are listed as hole transport materials that can be used in the light-emitting layer 130. Basol derivatives, aromatic hydrocarbons, stilbene derivatives, etc., can be used. The hole-transporting material may be a polymer compound.

[0147] ≪Hole transport layer≫ The hole transport layer 112 is a layer containing a hole transportable material, and is an example of the material used for the hole injection layer 111. The hole transport material shown can be used. The hole transport layer 112 is in the hole injection layer 111. Because it has the function of transporting the injected holes to the light-emitting layer 130, the HOM of the hole injection layer 111 It is preferable to have the same or close HOMO level as the O level.

[0148] Also, 1 × 10 -6 cm 2 It is preferable that the substance has a hole mobility of / Vs or higher. However, other materials may be used as long as they have higher hole transport capabilities than electron transport. Furthermore, the layer containing the material with high hole transport properties may be a single layer, or a double layer consisting of the aforementioned material. You may stack more than this amount.

[0149] ≪Electron transport layer≫ The electron transport layer 118 passes through the electron injection layer 119 to the other of the pair of electrodes (electrode 101 or electron It has the function of transporting electrons injected from pole 102) to the light-emitting layer 130. Electron transport material For this purpose, materials with higher electron transport capabilities than holes can be used, resulting in 1 × 10⁻⁶ -6 cm 2 It is preferable that the material has an electron mobility of / Vs or higher. Examples of materials (materials with electron transport properties) include π-electron-deficient types such as nitrogen-containing heteroaromatic compounds. Heteroaromatic compounds and metal complexes can be used. Specifically, they can be used in the light-emitting layer 130. The electron transport materials that can be used include quinoline ligands and benzoquinoline ligands. Examples include metal complexes having an oxazole ligand or a thiazole ligand. Oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, pyridine derivatives Examples include the compound, bipyridine derivatives, and pyrimidine derivatives. Also, 1 × 10 -6 cm 2 It is preferable that the material has an electron mobility of / Vs or higher. Any material with high electron transport properties other than those mentioned above may be used as the electron transport layer. The electron transport layer 118 may be a single layer, or two or more layers made of the above material may be stacked.

[0150] Furthermore, a layer for controlling the movement of electron carriers is provided between the electron transport layer 118 and the light-emitting layer 130. It is also acceptable to use materials with high electron transport properties, as described above, and materials with high electron trapping properties. A layer to which a small amount of is added, thereby suppressing the movement of electron carriers, carrier balance This makes it possible to adjust the balance. In this configuration, electrons penetrate the light-emitting layer. This has a significant effect in suppressing problems that may arise as a result (for example, a decrease in the lifespan of the device).

[0151] ≪Electron injection layer≫ The electron injection layer 119 promotes electron injection by reducing the electron injection barrier from the electrode 102. It has the function of being, for example, Group 1 metals, Group 2 metals, or their oxides and halides. Carbonates and the like can be used. In addition, the electron transport material shown above and the electron transport material therefor Composite materials exhibiting electron-donating properties can also be used. Examples of electron-donating materials include: Examples include Group 1 metals, Group 2 metals, or oxides thereof. Specifically These are lithium fluoride (LiF), sodium fluoride (NaF), and cesium fluoride (CsF). ), calcium fluoride (CaF2), lithium oxide (LiO2) x ) and other alkali metals Alkaline earth metals, or compounds thereof can be used. Also, fluoride Rare earth metal compounds such as bium (ErF3) can be used. Furthermore, electron injection layers can be used. An electride may be used in 119. For example, calcium Examples include substances obtained by adding a high concentration of electrons to a mixed oxide of aluminum and luminum. The injection layer 119 may be made of a material that can be used in the electron transport layer 118.

[0152] Furthermore, the electron injection layer 119 is a composite made by mixing an organic compound and an electron donor. Materials may be used. Such composite materials are created when electrons are released from the organic compound by an electron donor. Therefore, it exhibits excellent electron injection and electron transport properties. In this case, as an organic compound... Preferably, the material is one that is excellent at transporting the generated electrons, specifically, for example, the material described above. The electron transport layer 118 can be composed of materials (such as metal complexes or heteroaromatic compounds). The electron donor can be any substance that exhibits electron-donating properties towards organic compounds. Alkali metals, alkaline earth metals, and rare earth metals are preferred, as are lithium and sodium. Examples include cesium, magnesium, calcium, erbium, and ytterbium. Furthermore, alkali metal oxides and alkaline earth metal oxides are preferred, as are lithium oxides and calcium oxides. Examples include sium oxide and barium oxide. Also, Lewis plates such as magnesium oxide. Bases can also be used. Additionally, organic compounds such as tetrathiafulvalene (abbreviated as TTF) can be used. Objects can also be used.

[0153] Furthermore, 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. It can be formed by the above-mentioned method. In addition, the light-emitting layer, hole injection layer, hole transport layer, electron In addition to the materials mentioned above, the transport layer and electron injection layer also contain inorganic compounds such as quantum dots and high-molecular-weight materials. Sub-compounds (oligomers, dendrimers, polymers, etc.) may also be used.

[0154] Quantum dots include colloidal quantum dots, alloy quantum dots, and core-shell quantum dots. You may also use type quantum dots, core quantum dots, etc. Also, groups 2, 16, and 13 Includes element groups of Group 15, Groups 13 and 17, Groups 11 and 17, or Groups 14 and 15. Quantum dots may be used. Alternatively, cadmium (Cd), selenium (Se), zinc (Zn) may be used. ), sulfur (S), phosphorus (P), indium (In), tellurium (Te), lead (Pb), gallium Quantum dots containing elements such as um (Ga), arsenic (As), and aluminum (Al) are used. It's okay to be there.

[0155] ≪A pair of electrodes≫ Electrodes 101 and 102 function as the anode or cathode of the light-emitting element. 101 and electrode 102 are made of metals, alloys, conductive compounds, and mixtures or laminates thereof. It can be formed using [a specific method / tool].

[0156] Either electrode 101 or electrode 102 is formed by a conductive material having the function of reflecting light. Preferably, this is done. The conductive material is aluminum (Al) or an alloy containing Al. Examples include gold. Alloys containing Al include Al and L (where L is titanium (Ti) and neodymium). Includes (one or more of the following elements: Nd, Ni, and La) Examples include alloys containing Al and Ti, or Al, Ni, and La. Aluminum has low resistance and high light reflectivity. Also, aluminum is found in the Earth's crust. Because it is abundant and inexpensive, using aluminum reduces the cost of manufacturing light-emitting devices. It can reduce the amount of silver (Ag) or Ag and N (N is yttrium ( Y), Nd, Magnesium (Mg), Ytterbium (Yb), Al, Ti, Gallium ( Ga), zinc (Zn), indium (In), tungsten (W), manganese (Mn), Tin (Sn), iron (Fe), nickel, copper (Cu), palladium (Pd), iridium (Ir ), or alloys containing one or more gold (Au) may be used. Examples of alloys include alloys containing silver, palladium, and copper, alloys containing silver and copper, and alloys containing silver and magnesium. Alloys containing nesium, alloys containing silver and nickel, alloys containing silver and gold, and alloys containing silver and ytterbium Examples include alloys containing tungsten, chromium (Cr), and molybdenum (Mo). ), transition metals such as copper and titanium can be used.

[0157] Furthermore, the light emitted from the light-emitting layer passes through one or both of electrodes 101 and 102. And it is removed. Therefore, at least one of electrode 101 and electrode 102 transmits light. Preferably, it is formed from a conductive material having the function of being visible. The light transmittance is 40% or more and 100% or less, preferably 60% or more and 100% or less, and That resistivity is 1 × 10⁻⁶ -2 Examples include conductive materials with a conductivity of Ω·cm or less.

[0158] Furthermore, electrodes 101 and 102 have the function of transmitting light and the function of reflecting light. It may be formed from a conductive material having a visible light reflectance of 20. The resistivity is between % and 80%, preferably between 40% and 70%, and its resistivity is 1 × 10⁻⁶. -2 Examples of conductive materials include those with a conductivity of Ω·cm or less. For example, conductive metals, alloys, and conductive materials. It can be formed using one or more types of chemical compounds. Specifically, for example, Indium Tin Oxide (hereinafter referred to as ITO), silicon or silicon oxide Indium tin oxide containing silicon (abbreviation: ITSO), indium zinc oxide (Indium Zinc Oxide), indium-tin oxide containing titanium, indium- titanium oxide, indium oxide containing tungsten and zinc, and other metal oxides can be used. Also, a metal thin film with a light-transmitting degree (preferably a thickness of 1 nm or more and 30 nm or less) can be used. As the metal, for example, Ag or an alloy such as Ag and Al, Ag and Mg, Ag and Au, Ag and Yb, etc. can be used. Moreover, in this specification and the like, a material having a function of transmitting light may be a material having a function of transmitting visible light and having conductivity. For example, in addition to the oxide conductor represented by ITO as described above, it includes an oxide semiconductor or an organic conductor containing an organic substance. Examples of the organic conductor containing an organic substance include a composite material formed by mixing an organic compound and an electron donor (donor), a composite material formed by mixing an organic compound and an electron acceptor (acceptor), etc. Also, an inorganic carbon-based material such as graphene may be used. Also, the resistivity of the material is preferably 1×10 Ω·cm or less, more preferably 1×10

[0159] Ω·cm or less. In addition, one or both of the electrodes 101 and 102 may be formed by laminating a plurality of the above materials. Moreover, in order to improve the light extraction efficiency, in contact with an electrode having a function of transmitting light, the Also, a composite material formed by mixing an organic compound and an electron donor (donor), a composite material formed by mixing an organic compound and an electron acceptor (acceptor), etc. can be mentioned. Also, an inorganic carbon-based material such as graphene may be used. Also, the resistivity of the material is preferably 1×10 y composite materials formed by mixing an organic compound and an electron acceptor (acceptor), etc. In addition, an inorganic carbon-based material such as graphene may be used. Also, the resistivity of the material is preferably 1×10 Ω·cm or less, more preferably 1×10 5 Ω·cm or less, and even more preferably 1×10 4 Ω·cm or less. That is, it is less than or equal to.

[0160] In addition, one or both of the electrodes I and electrode 2 may be formed by laminating a plurality of the above materials. That is, it is possible to form one or both of the electrodes 101 and 102.

[0161] In addition, in order to improve the light extraction efficiency, in contact with an electrode having a function of transmitting light, the A material with a refractive index higher than that of the electrode may be formed. Such a material may transmit visible light. Any material that has the function of being conductive is acceptable, and even if it is a conductive material, it does not have that function. Other options include oxide conductors, oxide semiconductors, and organic materials. Examples of organic materials include the light-emitting layer, hole injection layer, hole transport layer, electron transport layer, or electric Examples of materials used in the sub-injection layer include those shown in the example. Also, inorganic carbon-based materials and thin films that allow light to pass through are also examples. These metals can also be used. Using these materials with high refractive indices, several nanometers to tens of nanometers Multiple layers may be stacked.

[0162] When electrode 101 or electrode 102 functions as a cathode, the work function is small. It is preferable that the material has a (3.8 eV or less) energy. For example, it is preferable that it has elements from Group 1 or Group 2 of the periodic table. Elements belonging to the group (alkali metals such as lithium, sodium, and cesium, calcium, stoichiometric compounds) Alkaline earth metals such as rontium, magnesium, etc., and alloys containing these elements (for example, Rare earth metals such as Ag and Mg, Al and Li, europium (Eu), Yb, and these rare earths Metal alloys, aluminum alloys, silver alloys, etc., can be used.

[0163] Furthermore, when electrode 101 or electrode 102 is used as the anode, the work function is large (4. It is preferable to use a material with a voltage of 0 eV or higher.

[0164] Furthermore, electrodes 101 and 102 are made of a conductive material that has the function of reflecting light and a material that transmits light. It may also be laminated with a conductive material having a function of passing through. In that case, electrode 101 and electrode 1 02 resonates the light with a desired wavelength from each light-emitting layer and intensifies the light of that wavelength. It is preferable because it can have a function to adjust the optical distance so that it can do so.

[0165] The methods for forming the film of electrodes 101 and 102 include sputtering, vapor deposition, printing, and coating. MBE (Molecular Beam Epitaxy), CVD, Pulse Ray The deposition method, ALD (Atomic Layer Deposition), etc., are used as appropriate. It is possible.

[0166] Circuit board Furthermore, a light-emitting element according to one aspect of the present invention is placed on a substrate made of glass, plastic, or the like. It is fine to manufacture it. In terms of the order in which it is manufactured on the substrate, it is fine to stack them in order from the electrode 101 side. You may also stack them sequentially starting from pole 102.

[0167] Examples of substrates on which a light-emitting element according to one aspect of the present invention can be formed include glass and quartz. , or plastic can be used. A flexible substrate may also be used. A substrate is a flexible substrate that can be bent, for example, polycarbonate Examples include plastic substrates made of nate, polyarylate, etc. Also, films, Inorganic vapor-deposited films can also be used. Note: The manufacturing process for light-emitting elements and optical elements. Anything other than these that functions as a support in the context is acceptable. Alternatively, Any device that has the function of protecting optical elements and other optical components is acceptable.

[0168] For example, in the present invention, a light-emitting element can be formed using various substrates. The type of substrate is not particularly limited. One example of such a substrate is a semiconductor substrate (e.g., a single crystal). Substrates (or silicon substrates), SOI substrates, glass substrates, quartz substrates, plastic substrates, metal Substrates, stainless steel substrates, substrates with stainless steel foil, tungsten Substrate, substrate having tungsten foil, flexible substrate, laminated film, fibrous These include cellulose nanofibers (CNF) containing the material, paper, or substrate films. Examples of lath substrates include barium borosilicate glass, aluminobrosilicate glass, or Examples include soda-lime glass. Flexible substrates, laminated films, and base films are also used. For example, the following can be cited: For example, polyethylene terephthalate (PET), Polyethylene naphthalate (PEN), polyethersulfone (PES), polytetrafluoroethylene There are plastics such as ethylene (PTFE). Or, as an example, Examples include resins such as acrylic. Alternatively, one example is polypropylene, polyester, and polypropylene. Examples include refractory vinyl or polyvinyl chloride. Alternatively, as an example, polyamide. These include polyimides, aramids, epoxy, inorganic vapor-deposited films, and paper products.

[0169] 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. The release layer is provided on top of the light-emitting element. After partially or completely completing the child component, it is separated from the circuit board and used for transferring it to another circuit board. This allows for the transfer of light-emitting elements to substrates with poor heat resistance or flexible substrates. Oh, the aforementioned delamination layer has, for example, a laminated inorganic film structure of a tungsten film and a silicon oxide film. Configurations such as the one shown, or a configuration in which a resin film such as polyimide is formed on the substrate, can be used.

[0170] In other words, a light-emitting element is formed using one substrate, and then the light-emitting element is transferred to another substrate. The light-emitting element may be placed on a different substrate. An example of a substrate on which the light-emitting element is placed is the above In addition to the substrates mentioned above, there are also cellophane substrates, stone substrates, wood substrates, and cloth substrates (natural fibers (silk, cotton, Hemp), synthetic fibers (nylon, polyurethane, polyester) or regenerated fibers (acetate) (including t, cupro, rayon, recycled polyester, etc.), leather substrate, or rubber substrate. These substrates can be used to create light-emitting elements that are less prone to breakage and have high heat resistance. This can be a child, a lightweight light-emitting element, or a thinned light-emitting element.

[0171] Furthermore, a field-effect transistor (FET), for example, is formed on the aforementioned substrate, and the FET and A light-emitting element may be fabricated on electrically connected electrodes. This allows the FET to emit light. An active-matrix type display device can be fabricated that controls the driving of optical elements.

[0172] In this embodiment, one aspect of the present invention has been described. Or, other embodiments may be described. In this context, one aspect of the present invention will be described. However, this aspect of the present invention is not limited to these. Not done. In other words, various aspects of the invention are described in this embodiment and other embodiments. Therefore, one aspect of the present invention is not limited to a specific aspect. For example, one aspect of the present invention While an example of its application to a light-emitting element has been shown, one aspect of the present invention is not limited thereto. For example, depending on the circumstances, one aspect of the present invention may be suitable for a light-emitting element. It is not necessary to use it. Alternatively, for example, in one aspect of the present invention, the EL layer is made of a host material and a fluorescent A guest material that has the ability to emit light or converts triplet excitation energy into light emission. A guest material having the ability to be exchanged, and a host material having singlet excitation energy The difference between the energy level and the triplet excitation energy level is greater than 0 eV and less than or equal to 0.2 eV. An example of a case having a first organic compound has been shown, but one aspect of the present invention is not limited thereto. In some cases, or depending on the circumstances, in one aspect of the present invention, for example, the host material is The difference between the singlet excitation energy level and the triplet excitation energy level is greater than 0 eV, which is 0.2. It is not necessary to have a first organic compound with an eV of less than or equal to eV. Alternatively, the first organic compound is The difference between the singlet excitation energy level and the triplet excitation energy level is greater than 0 eV, which is 0.2. It does not have to be less than eV. Or, for example, in one aspect of the present invention, the first organic compound and the An example has been shown of when two organic compounds form an excited complex, but one aspect of the present invention is this It is not limited to the present invention. In some cases, or depending on the circumstances, one aspect of the present invention may include, for example, The first organic compound and the second organic compound do not necessarily have to form an excited complex. Or, For example, in one aspect of the present invention, one of the first organic compound and the second organic compound is the first The organic compound and the second organic compound have HOMO levels higher than or equal to the other HOMO level, Furthermore, the LUMO level of the other organic compound is higher than the LUMO level of the first organic compound and the second organic compound. While examples of cases having positions have been shown, one aspect of the present invention is not limited thereto. Or, depending on the circumstances, in one aspect of the present invention, for example, a first organic compound and a second One of the organic compounds is the HOMO level of the other of the first organic compound and the second organic compound. Having the above HOMO levels, and the other L of the first organic compound and the second organic compound The configuration does not necessarily have to have a LUMO level higher than or equal to the UMO level.

[0173] The configuration shown in this embodiment can be used in appropriate combination with other embodiments. Cut.

[0174] (Embodiment 2) In this embodiment, the light-emitting element has a configuration different from that shown in Embodiment 1, and The light-emitting mechanism of the light-emitting element will be explained below using Figures 4(A), (B), and (C). In addition, in Figure 4(A), the same symbols are used for parts that have the same function as those shown in Figure 1(A). The hatch pattern is used, and the symbols may be omitted. Also, in places with similar functions, Similar symbols may be used, and their detailed explanations may be omitted.

[0175] <Example of light-emitting element configuration> Figure 4(A) is a schematic cross-sectional view of a light-emitting element 152 according to one embodiment of the present invention.

[0176] The light-emitting element 152 has a pair of electrodes (electrode 101 and electrode 102), and between the pair of electrodes It has an EL layer 100 provided therein. The EL layer 100 has at least an emissive layer 140. .

[0177] In addition, in the light-emitting element 152, electrode 101 functions as the anode and electrode 102 functions as the cathode. Assuming it functions in this way, the following explanation will be given, but the configuration of the light-emitting element 152 can be reversed as well. No.

[0178] Figure 4(B) is a schematic cross-sectional view showing an example of the light-emitting layer 140 shown in Figure 4(A). The light-emitting layer 140 shown in B) has a host material 141 and a guest material 142. The host material 141 comprises organic compound 141_1 and organic compound 141_2.

[0179] Furthermore, as the guest material 142, any luminescent organic material may be used. Preferably, the material is one that can emit phosphorescence (hereinafter also referred to as a phosphorescent material). In the following explanation, the configuration using a phosphorescent material as guest material 142 will be described below. Let me explain. Note that guest material 142 may be interpreted as phosphorescent material.

[0180] <Light-emitting mechanism of light-emitting element> Next, the light-emitting mechanism of the light-emitting layer 140 will be explained below.

[0181] The organic compound 141_1 and organic compound contained in the host material 141 in the light-emitting layer 140 Substance 141_2 forms an excited complex.

[0182] The combination of organic compound 141_1 and organic compound 141_2 forms an excited complex. Any combination that allows this is acceptable, but one of them is a compound that has hole transport properties, and the other It is more preferable that the compound has electron transport properties. In this case, donor-acceptor This facilitates the formation of tar-type excited complexes, enabling efficient formation of excited complexes.

[0183] Furthermore, as for the combination of organic compound 141_1 and organic compound 141_2, one of them is It has a HOMO level higher than the other HOMO level, and a LUM level higher than the other LUMO level. It is preferable to have an O level.

[0184] Organic compound 1 in the energy band diagrams of Figures 2(A) and 2(B) described in Embodiment 1 Similar to 31_1 and organic compound 131_2, for example, organic compound 141_1 is a hole channel When organic compound 141_2 has electron transport properties, the organic compound 141_1 The HOMO level is above the HOMO level of organic compound 141_2, and organic compound 1 The LUMO level of 41_1 is preferably higher than or equal to the LUMO level of organic compound 141_2. Alternatively, organic compound 141_2 has hole transport properties, and organic compound 141_1 has electron transport properties. When it has molecular transport properties, the HOMO level of organic compound 141_2 is the same as that of organic compound 141_1 The HOMO level is above that of the organic compound 141_2, and the LUMO level of the organic compound It is preferable that the LUMO level is above that of 141_1. In this case, the organic compound 141_1 The excited complex formed by and organic compound 141_2 has one HOMO level and the other LUMO level An excited complex is formed with an excitation energy that roughly corresponds to the energy difference with the level. The difference between the HOMO level of organic compound 141_1 and the HOMO level of organic compound 141_2, and The difference between the LUMO levels of organic compound 141_1 and organic compound 141_2 is: Each is preferably 0.2 eV or higher, and more preferably 0.3 eV or higher.

[0185] Furthermore, based on the relationship between the HOMO and LUMO levels described above, organic compound 141_1 and In combination with compound 141_2, one has an oxidation potential greater than the oxidation potential of the other. Furthermore, it is preferable that the reduction potential is greater than or equal to that of the other.

[0186] In other words, organic compound 141_1 has hole transport properties, and organic compound 141_2 has electron transport properties. When it has transport properties, the oxidation potential of organic compound 141_1 is the oxidation potential of organic compound 141_2. It is below the rank, and the reduction potential of organic compound 141_1 is the reduction potential of organic compound 141_2. It is preferable that the potential is below a certain level. Alternatively, the organic compound 141_2 has hole transport properties. When organic compound 141_1 has electron transport properties, the oxidation potential of organic compound 141_2 is: The oxidation potential of organic compound 141_1 is less than or equal to the reduction potential of organic compound 141_2. It is preferable that the reduction potential is below that of organic compound 141_1.

[0187] Furthermore, the combination of organic compound 141_1 and organic compound 141_2 exhibits hole transport properties. In the case of a combination of a compound that possesses electron transport properties and a compound that has electron transport properties, the mixing ratio of the two compounds... This makes it possible to easily control the carrier balance. Specifically, it has hole transport properties. Compounds: Compounds with electron transport properties = preferably in the range of 1:9 to 9:1 (by weight). Furthermore, having this configuration makes it easy to control the career balance. Furthermore, the carrier recombination region can be easily controlled.

[0188] Furthermore, it is preferable that the organic compound 141_1 is a thermally activated delayed phosphor. Alternatively, Preferably, it has the function of exhibiting thermally activated delayed fluorescence at room temperature. Organic compound 141_1, on its own, is in a triplet excited state, and then, through reverse intersystem crossing, it is in a singlet excited state. It is a material that can generate [something]. To do so, singlet excitation energy levels and triplet excitation energy levels are required. It is preferable that the difference from the Ghee level is greater than 0 eV and 0.2 eV or less. If 141_1 has the function of converting triplet excitation energy into singlet excitation energy Often, thermally activated delayed fluorescence is not required.

[0189] Furthermore, organic compound 141_1 has a hole-transporting skeleton and an electron-transporting skeleton. It is preferable that the above is present. Furthermore, the organic compound 141_1 is a π-electron-rich heteroaromatic compound. Having at least one of a skeleton or an aromatic amine skeleton, and a π-electron-deficient heteroaromatic skeleton It is preferable that it has a grade. Furthermore, a π-electron-rich complex aromatic skeleton and a π-electron-deficient complex aromatic skeleton are preferable. Direct bonding with the aromatic skeleton results in both donor properties and π-electron deficiency for π-electron-rich complex aromatic skeletons. The acceptor properties of the complex aromatic skeleton are both strengthened, and the singlet excitation energy levels and triple This is particularly preferable because the difference in the number excitation energy levels becomes smaller. Organic compound 141_1, Due to its strong donor and acceptor properties, organic compound 141_1 and organic compound This facilitates the formation of a donor-acceptor type excitation complex with 141_2.

[0190] Furthermore, the region where the HOMO molecular orbital is distributed in organic compound 141_1 and the LUMO It is preferable that the overlap with the region where molecular orbitals are distributed is small.

[0191] The excited complex formed by organic compound 141_1 and organic compound 141_2 is formed by one of the organic compounds Because the compound has a HOMO molecular orbital and the other organic compound has a LUMO molecular orbital. The overlap between the HOMO molecular orbital and the LUMO molecular orbital is extremely small. The resulting complex exhibits a smaller difference between the singlet excitation energy level and the triplet excitation energy level. Therefore, the excited complex formed by organic compound 141_1 and organic compound 141_2 is three The difference between the doublet excitation energy level and the singlet excitation energy level is preferably greater than 0 eV. It is less than 0.2 eV.

[0192] Here, in the light-emitting layer 140, organic compound 141_1 and organic compound 141_2, Figure 4(C) shows the energy level correlation with material 142. The notations and symbols are as follows. ·Host(141_1): Host material (organic compound 141_1) ·Host(141_2): Host material (organic compound 141_2) ·Guest(142): Guest material 142 (phosphorescent material) ·S PH1 : S1 level of the host material (organic compound​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​) are each organic compound (with S1 level (S PH1 and S PH2 ) Because it becomes lower, the excited state of host material 141 (excited complex) is at a lower excitation energy. This makes it possible to form a light-emitting element 152. It is possible.

[0195] And the excited complex (S PE ) and (T PE The energy of both ) is used by guest material 142 Light emission is obtained by shifting to the lowest level of the triplet excited state of the (phosphorescent material) (Figure 4(C)). (See routes E8 and E9).

[0196] Note that the T1 level of the excited complex (T PE ) is the T1 level of guest material 142 (T PG )twist A larger value is preferable. This increases the singlet excitation energy of the generated excited complex. The triplet excitation energy is the S1 level (S) of the excited complex. PE ) and T1 level (T PE )mosquito The T1 level of guest material 142 (T PG Energy can be transferred to ).

[0197] By configuring the light-emitting layer 140 as described above, the guest material 142 (phosphorescent material) of the light-emitting layer 140 This makes it possible to efficiently obtain light emission from ).

[0198] Furthermore, the processes of Route E7, Route E8, and Route E9 described above are as specified in this specification, etc. ExTET (Exciplex-Triplet Energy Transfer) ) is sometimes referred to as [this]. In other words, the light-emitting layer 140 is made from an excited complex and a guest material 142 There is an excitation energy supply to it. Also, in this case, T is not necessarily PE From S PE Inverse terms to High cross-efficiency is not necessary, S PE Since a high emission quantum yield from the material is not necessary, the material width A wider range of choices will be available.

[0199] The above reactions can be represented by the following general formulas (G1) to (G3).

[0200] D + +A - → (D·A) * (G1) (D·A) * +G → D+A+G * (G2) G * → G+hν (G3)

[0201] The general formula (G1) is such that one of the organic compounds 141_1 and 141_2 has a hole. Receipt (D) + ), the other party receives an electron (A - ) by which organic compound 141_1 and Organic compound 141_2 is excited into complex ((D·A)) * This is a reaction that produces ). Also, the general formula (G2) is an excited complex ((D·A) * Energy transfer from ) to guest material 142(G) This generates an excited state (G) of guest material 142. * This is a reaction that produces ) the general formula (G As shown in 3), the excited guest material 142 emits light (hν).

[0202] Furthermore, in order to efficiently transfer excitation energy from the excited complex to the guest material 142, , the T1 level of the excited complex (T PE ) forms an excited complex with each organic compound (organic compound 14 T1 level of 1_1 and organic compound 141_2) (T PH1and T PH2 ) is equivalent to, Smaller is preferable. This allows the triplet excitation energy of the excited complex by each organic compound to be smaller. Energy quenching becomes less likely, and energy transfer to guest material 142 occurs more efficiently. do.

[0203] For example, in at least one of the compounds that form an excited complex, S1 level and T1 level When the difference with the position is large, the T1 level of the excited complex (T PE ) is equivalent to the T1 level of each compound. Therefore, it is necessary to set a lower energy level. Also, the T1 level of the guest material is the excited complex It is preferable that the T1 level is equivalent to or smaller than the S level of at least one of the compounds. When the difference between the 1st level and the T1 level is large, it has a high triplet excitation energy level. Materials that emit light with high emission energy, such as blue light, are used as guest materials. It becomes difficult to use it as material 142.

[0204] On the other hand, in one aspect of the present invention, organic compound 141_1 is at the S1 level (S PH1 ) and T 1 level (T PH1 The difference between ) and T1 is small. Therefore, the S1 level and T1 of organic compound 141_1 It is possible to raise both levels simultaneously, and it is possible to raise the T1 level of the excited complex. Therefore, one aspect of the present invention is not limited to the luminescence color of the guest material 142, for example, From light emission with high luminescence energy, such as blue, to light emission with low luminescence energy, such as red... It can be suitably used in light-emitting devices that exhibit various types of light emission, including light.

[0205] Furthermore, when the organic compound 141_1 has a skeleton with strong donor properties, it can be injected into the light-emitting layer 140. The holes that are created are injected into organic compound 141_1, making them easier to transport. Compound 141_2 is an acceptor that has stronger acceptor properties than organic compound 141_1. It is preferable that it has a sex skeleton. In this way, organic compound 141_1 and organic compound 141 With _2, it becomes easier to form an excited complex. Alternatively, organic compound 141_1 acts as an acceptor. When it has a strong skeleton, electrons injected into the light-emitting layer 140 into the organic compound 141_1 It becomes easier to inject and transport. At this time, organic compound 141_2 becomes organic compound 141_ It is preferable to have a donor skeleton with stronger donor properties than 1. Compound 141_1 and organic compound 141_2 are more likely to form an excited complex.

[0206] Furthermore, organic compound 141_1, in its elemental form, undergoes reverse intersystem crossing to achieve a triplet excitation energy of 1 It has the function of converting to multiplet excitation energy, and organic compound 141_1 is organic compound 1 When the configuration is such that it is difficult to form an excited complex with 41_2, for example, the H of organic compound 141_1 The OMO level is higher than the HOMO level of organic compound 141_2, and organic compound 141_ When the LUMO level of 2 is higher than the LUMO level of organic compound 141_1, the light-emitting layer 140 The injected carriers, electrons and holes, are both injected into and transported by the organic compound 141_1. This becomes easier. In this case, due to the hole transport and electron transport properties of organic compound 141_1 Therefore, it is necessary to control the carrier balance in the light-emitting layer 140. For this reason, organic compounds 141_1 has the function of converting triplet excitation energy into singlet excitation energy on its own. In addition to that, the molecular structure must have a suitable carrier balance. This makes it difficult to design the molecular structure. On the other hand, in one embodiment of the present invention, organic compound 141_ Because electrons are injected into one of 1 and organic compound 141_2 and holes are injected into the other and transported. The carrier balance can be easily controlled by the mixing ratio, resulting in high luminescence. A light-emitting element that indicates a rate can be provided.

[0207] Also, for example, the HOMO level of organic compound 141_2 is the HOMO level of organic compound 141_1. The LUMO level of organic compound 141_1 is higher than the O level, and the LUMO level of organic compound 141_2 is higher than that of organic compound 141_2. When the level is higher than the LUMO level, electrons and holes, which are carriers injected into the light-emitting layer 140 Both are injected into organic compound 141_2 and become easier to transport. Therefore, organic compound 141 Carrier recombination is likely to occur in _2. Organic compound 141_2 undergoes reverse intersystem crossing in its elemental form. If it does not have the function to convert triplet excitation energy to singlet excitation energy, Because the energy difference between the S1 and T1 levels of organic compound 141_2 becomes large, the guest The energy difference between the T1 level of material 142 and the S1 level of organic compound 141_2 is large. Therefore, the driving voltage of the light-emitting element increases by the amount of the voltage corresponding to the energy difference. This happens. On the other hand, in one embodiment of the present invention, each organic compound (organic compound 141_1 and Organic compounds (141_2) can be synthesized at an excitation energy lower than the excitation energy level of the elemental compound. It becomes possible to form an excited complex with compound 141_1 and organic compound 141_2. Therefore, it is possible to reduce the driving voltage of the light-emitting element, and to provide a light-emitting element with low power consumption. It can be provided.

[0208] In Figure 4(C), the S1 level of organic compound 141_2 is the same as that of organic compound 141_ The T1 level of organic compound 141_1 is higher than the S1 level of 1, and the T1 level of organic compound 141_2 is higher than the T1 level of organic compound 141_2. Although examples have been given of cases higher than the level, the present invention is not limited thereto. Organic compound 1 The S1 level of 41_1 is higher than the S1 level of organic compound 141_2, and organic compound 141_1 The T1 level of is acceptable to be higher than the T1 level of organic compound 141_2. Alternatively, the organic compound It is acceptable for the S1 levels of compound 141_1 and organic compound 141_2 to be at the same level. Alternatively, the S1 level of organic compound 141_2 is higher than the S1 level of organic compound 141_1. Even if the T1 level of organic compound 141_2 is high and higher than the T1 level of organic compound 141_1 That's fine. However, in either case, the T1 level of the excited complex will form the excited complex. Equivalent to the T1 level of each organic compound (organic compound 141_1 and organic compound 141_2). Or, a lower value is preferable.

[0209] Furthermore, the mechanism of the intermolecular energy transfer process between the host material 141 and the guest material 142. Similar to Embodiment 1, the Förster mechanism (dipole-dipole interaction) and the Deck It can be explained by two mechanisms of the star mechanism (electron exchange interaction). For the Tur mechanism and Dexter mechanism, refer to Embodiment 1.

[0210] ≪A concept for enhancing energy transfer≫ In energy transfer by the Förster mechanism, the energy transfer efficiency φ ET is, Photon quantum yield φ (fluorescence quantum yield if discussing energy transfer from singlet excited states) A higher value is better. Also, the emission spectrum of the host material 141 (energy from the singlet excited state) When discussing energy transfer, use the fluorescence spectrum and the absorption spectrum of guest material 142 (single). It is preferable that there is a large overlap with the absorption corresponding to the transition from the ground state to the triplet excited state. Furthermore, it is preferable that the molar extinction coefficient of guest material 142 is also high. The emission spectrum of material 141 and the absorption band that appears at the longest wavelength side of guest material 142 It means overlapping.

[0211] Furthermore, in energy transfer by the Dexter mechanism, the rate constant k h*→g Make it bigger To do this, we need to consider the emission spectrum of the host material 141 (to discuss energy transfer from the singlet excited state). (In this case, the fluorescence spectrum) and the absorption spectrum of guest material 142 (from singlet ground state to three) A larger overlap with the absorption corresponding to the transition to the multiplet excited state is desirable. Therefore, The optimization of energy transfer efficiency involves the emission spectrum of the host material 141 and the guest material 142. This is achieved by the overlap with the absorption band that appears at the longest wavelength.

[0212] Furthermore, similar to the energy transfer from host material 141 to guest material 142, the excited complex The energy transfer process from to guest material 142 is also related to the Förster mechanism and the Deck Energy transfer occurs through both mechanisms in the star mechanism.

[0213] Therefore, one aspect of the present invention provides an energy transfer mechanism that can efficiently transfer energy to the guest material 142. Organic compound 141, a combination that forms an excited complex having the function of an energy donor. The present invention provides a light-emitting element having _1 and organic compound 141_2 as the host material 141. The excited complexes formed by organic compound 141_1 and organic compound 141_2 are singlet excited It has the characteristic that the energy level and the triplet excitation energy level are in close proximity. Therefore, the excitation complex formed in the light-emitting layer 140 is organic compound 141_1 and organic compound It becomes possible to form it with a lower excitation energy than material 141_2. Therefore, light-emitting element 152 In this case, the driving voltage can be reduced. Furthermore, the energy from the singlet excited state of the excited complex Energy transfer occurs to the triplet excited state of guest material 142, which acts as an energy acceptor. To make it easier, the emission spectrum of the excited complex and the longest wavelength side of guest material 142 ( It is preferable that the absorption band appearing on the low-energy side overlaps with the guest material. This can increase the efficiency of generating the 142 triplet excited states.

[0214] <Examples of materials that can be used for the light-emitting layer> Next, the materials that can be used for the light-emitting layer 140 will be described below.

[0215] In the light-emitting layer 140, the host material 141 is the most abundant by weight, followed by the guest material 142 The (phosphorescent material) is dispersed in the host material 141. Host material 141 of the light-emitting layer 140 ( The T1 levels of organic compounds 141_1 and 141_2 are guest levels of the luminescent layer 140. It is preferable that the T1 level is higher than that of the material (guest material 142).

[0216] Organic compound 141_1 is preferably characterized by exhibiting thermally activated delayed fluorescence at room temperature. i. That is, the energy difference between the triplet excitation energy level and the singlet excitation energy level. It is preferable that the ratio is small, specifically between the triplet excitation energy level and the singlet excitation energy. - The energy difference with the level is preferably greater than 0 eV and 0.2 eV or less, more preferably It is greater than 0 eV and less than or equal to 0.1 eV. The triplet excitation energy level and the singlet excitation energy level Examples of materials with a small energy difference from the energy level include thermally activated delayed fluorescence materials. As the thermally activated delayed fluorescence material, the material exemplified in Embodiment 1 can be used. .

[0217] Furthermore, organic compound 141_1 has triplet excitation energy levels and singlet excitation energy levels It is sufficient that the energy difference with the position is small, and it does not need to have the function of exhibiting thermally activated delayed fluorescence. In that case, organic compound 141_1 is a π-electron-rich heteroaromatic skeleton or aromatic ammonium compound. At least one of the n skeletons and the π-electron-deficient heteroaromatic skeleton are connected by an m-phenylene group or It is preferable to have a structure that is bonded via a structure having at least one o-phenylene group. It is so. Or, it has at least one m-phenylene group or o-phenylene group. Preferably, the structure has a bonded structure via an arylene group, and the arylene group is biphenyl It is even more preferable that it be a len group. Doing so raises the T1 level of organic compound 141_1. This can be done. In this case as well, the π-electron-deficient complex aromatic skeleton is dia A din skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), or a triazine skeleton It is preferable to have it. Also, the π-electron-rich heteroaromatic skeleton is an acridine skeleton, pheno xazine skeleton, phenothiazine skeleton, furan skeleton, thiophene skeleton, and pyrrole skeleton It is preferable to have one or more selected from among them. The indole skeleton and carbazole skeleton are preferred, and 3-(9-phenyl-9H- A carbazole-3-yl)-9H-carbazole skeleton is particularly preferred.

[0218] Organic compound 141_2 is a combination that can form an excited complex with organic compound 141_1. A combination is preferred. Specifically, zinc or aluminum-based metal complexes, or oxadiazole derivatives. Body, triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzox Noxaline derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, pyrimidine derivatives The body, triazine derivatives, pyridine derivatives, bipyridine derivatives, and phenanthroline derivatives Examples of heteroaromatic compounds such as isomers, or aromatic amines and carbazole derivatives, etc. The electron-transporting material and hole-transporting material shown in Embodiment 1 can be used. In this case, The emission peak of the excited complex formed by organic compound 141_1 and organic compound 141_2 is Guest material 142 (phosphorescent material) Triplet MLCT (Metal to Light C The absorption band of the (harge transfer) transition, more specifically, the absorption band on the longest wavelength side. Overlapping with these are organic compound 141_1, organic compound 141_2, and guest material 14 It is preferable to select 2 (phosphorescent material). This dramatically improves the luminescence efficiency. It can be used as an optical element. However, if a thermally activated delayed fluorescence material is used instead of a phosphorescent material... In this case, it is preferable that the absorption band on the longest wavelength side is a singlet absorption band.

[0219] Guest material 142 (phosphorescent material) can be iridium, rhodium, or platinum-based organic Examples include metal complexes, or metal complexes in particular, organoiridium complexes, such as iridium Orthometallic complexes are preferred. 4H-triazole is a suitable ligand for orthometallation. Ligands, 1H-triazole ligands, imidazole ligands, pyridine ligands, pyrimidines Examples include ligands, pyrazine ligands, or isoquinoline ligands. Examples include platinum complexes having porphyrin ligands.

[0220] Examples of substances that have a blue or green emission peak include tris{2-[5-(2 -methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazo [Ir-3-yl-κN2]phenyl-κC}iridium(III) (abbreviation: Ir(mpp) tz-dmp)3), Tris(5-methyl-3,4-diphenyl-4H-1,2,4-) Ryasolato) Iridium(III) (abbreviation: Ir(Mptz)3), Tris[4-(3- [Biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato] Lydium(III) (abbreviation: Ir(iPrptz-3b)3), Tris[3-(5-Bif [Phenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]iridi Um(III) (abbreviation: Ir(iPr5btz)3), a 4H-triazole skeleton organometallic iridium complexes having, or tris[3-methyl-1-(2-methylphenyl) -5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: Ir (Mptz1-mp)3), Tris(1-methyl-5-phenyl-3-propyl-1H- 1,2,4-Triazolat) Iridium(III) (Abbreviation: Ir(Prptz1-Me) 3) Organometallic iridium complexes having a 1H-triazole skeleton, or fac-tri S[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole] Rydium(III) (abbreviation: Ir(iPrpmi)3), Tris[3-(2,6-dimethyl Iridium (I)-7-methylimidazo[1,2-f]phenantridinato]iridium II) (abbreviation: Ir(dmpimpt-Me)3) has an imidazole skeleton iridium metal complexes and bis[2-(4',6'-difluorophenyl)pyridinate- N,C 2’ Iridium(III) tetrakis(1-pyrazolyl) borate (abbreviation: FI) r6), bis[2-(4',6'-difluorophenyl)pyridinate-N,C 2’ ] Iri Dium(III) picolinate (abbreviation: Firpic), bis{2-[3',5'-bis (trifluoromethyl)phenyl]pyridinate-N,C 2’ Iridium(III) pico Rinart (abbreviation: Ir(CF3ppy)2(pic)), Bis[2-(4',6'-Jif Luorophenyl)pyridinate-N,C 2’ Iridium(III) acetylacetonate (abbreviation: Fir(acac)) contains a phenylpyridine derivative having an electron-withdrawing group. Examples include organometallic iridium complexes used as ligands. Among those mentioned above, 4H-triazole is one example. Organometallic iridium complexes with a skeletal structure are particularly preferred due to their excellent reliability and luminescence efficiency. .

[0221] Furthermore, examples of substances that have a green or yellow emission peak include tris(4-methyl Iridium(III) (abbreviation: Ir(mppm)3), 6-phenylpyrimidinato Tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: I r(tBuppm)3), (acetylacetonate)bis(6-methyl-4-phenylpyryl) Iridium(III) (abbreviation: Ir(mppm)2(acac)), (acetyl Luacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium III) (Abbreviation: Ir(tBuppm)2(acac)), (acetylacetonato)bis [4-(2-norbornyl)-6-phenylpyrimidinato]iridium(III) (abbreviation) :Ir(nbppm)2(acac)),(acetylacetonato)bis[5-methyl-6 -(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: Ir(mpmppm)2(acac)), (acetylacetonato)bis{4,6-dimethicone} Lu-2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN3]phenyl- κC} Iridium(III) (abbreviation: Ir(dmppm-dmp)2(acac)), ( Acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III)( Abbreviation: Organometallic irritants with a pyrimidine skeleton, such as Ir(dppm)2(acac) Dium complexes, and (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazine Iridium(III) (abbreviation: Ir(mppr-Me)2(acac)), (acetyl Luacetonato)bis(5-isopropyl-3-methyl-2-phenylpyradinato)iridi Pyrazine bones like Um(III) (abbreviation: Ir(mppr-iPr)2(acac)) iridium organometallic complexes with a specific classification, and tris(2-phenylpyridinato-N,C) 2’ ) Iridium(III) (abbreviation: Ir(ppy)3), bis(2-phenylpyridinate-N) ,C 2’ Iridium(III) acetylacetonate (abbreviation: Ir(ppy)2(ac) ac)), bis(benzo[h]quinolinate)iridium(III)acetylacetonate (Abbreviation: Ir(bzq)2(acac)), Tris(benzo[h]quinolinato)iridiu Mu(III) (abbreviation: Ir(bzq)3), Tris(2-phenylquinolinato-N,C) 2 ’ ) Iridium(III) (abbreviation: Ir(pq)3), bis(2-phenylquinolinazole- N,C 2’ Iridium(III) acetylacetonate (abbreviation: Ir(pq)2(ac) Organometallic iridium complexes having a pyridine skeleton, such as ac)), and bis(2,4-diph Enyl-1,3-oxazolato-N,C 2’ Iridium(III) Acetylaceton (abbreviation: Ir(dpo)2(acac)), bis{2-[4'-(perfluorophenicol) [Phenyl]pyridinate-N,C 2’ Iridium(III) acetylacetonate ( Abbreviation: Ir(p-PF-ph)2(acac)), bis(2-phenylbenzothiazolat -N,C 2’ Iridium(III) acetylacetonate (abbreviation: Ir(bt)2(a) In addition to organometallic iridium complexes such as CAC, there are also tris(acetylacetonate)(monophenate). Nanthroline terbium(III) (abbreviation: Tb(acac)3(Phen)) Examples include rare earth metal complexes. Among those mentioned above, organometallic ylids having a pyrimidine skeleton are particularly noteworthy. Dium complexes are particularly preferred because they exhibit outstanding reliability and luminescence efficiency.

[0222] Furthermore, examples of substances that have a yellow or red emission peak include (diisobutyryl Methanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(II) I) (abbreviation: Ir(5mdppm)2(dibm)), bis[4,6-bis(3-methyl [Phenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: Ir (5 mdppm)2(dpm)), bis[4,6-di(naphthalene-1-yl)pyrimid Nat] (dipivaloylmethanato) Iridium(III) (Abbreviation: Ir(d1npm)2) Organometallic iridium complexes having a pyrimidine skeleton such as dpm, and (acetylacet Tonato)bis(2,3,5-triphenylpyradinato)iridium(III) (abbreviation: I r(tppr)2(acac)), bis(2,3,5-triphenylpyrazinate)(dipy Valoylmethanato) Iridium(III) (abbreviation: Ir(tppr)2(dpm)), ( Acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato] Pyrazine bones like lysium(III) (abbreviation: [Ir(Fdpq)2(acac)]) iridium organometallic complexes with a specific classification, and tris(1-phenylisoquinolinato-N,C) 2 ’ Iridium(III) (abbreviation: Ir(piq)3), bis(1-phenylisoquinol) Nato-N,C 2’ Iridium(III) acetylacetonate (abbreviation: Ir(piq)) In addition to organometallic iridium complexes having a pyridine skeleton like 2(acac)), 2,3, 7,8,12,13,17,18-Octaethyl-21H,23H-Porphyrin Platinum ( Platinum complexes such as (II) (abbreviation: PtOEP), and tris(1,3-diphenyl-1,3) -Propanedionato) (monophenanthroline) europium(III) (abbreviation: Eu( DBM)3(Phen)), Tris[1-(2-tenoyl)-3,3,3-trifluoro [Acetonato](monophenanthroline) europium(III) (abbreviation: Eu(TTA)) Examples include rare earth metal complexes such as 3(Phen)). Among those mentioned above, pyrimidine bone Organometallic iridium complexes with a specific rating are particularly favored due to their outstanding reliability and luminescence efficiency. Furthermore, organometallic iridium complexes with a pyrazine skeleton exhibit good coloration red luminescence. It can be obtained.

[0223] The light-emitting material included in the light-emitting layer 140 is capable of converting triplet excitation energy into light emission. Any material will do. A material that can convert the triplet excitation energy into light emission is a phosphorescent material. In addition, thermally activated delayed fluorescence materials can be mentioned. Therefore, the part that was described as phosphorescent material is relevant. Therefore, it is acceptable to interpret this as a thermally activated delayed fluorescence material.

[0224] When a thermally activated delayed fluorescence material is composed of one type of material, specifically, in the embodiment The thermally activated delayed fluorescence material shown in 1 can be used.

[0225] The light-emitting layer 140 can also be composed of two or more layers. For example, the first When the first light-emitting layer and the second light-emitting layer are stacked in order from the hole transport layer side to form the light-emitting layer 140, A material having hole transport properties is used as the host material for the first light-emitting layer, and the host material for the second light-emitting layer One such configuration involves using materials that possess electron-transporting properties.

[0226] Furthermore, in the light-emitting layer 140, materials other than the host material 141 and the guest material 142 are used. It's okay to have it.

[0227] The light-emitting layer 140 is produced by vapor deposition (including vacuum deposition), inkjet, coating, and It can be formed by methods such as labia printing. In addition to the materials mentioned above, quantum dots, etc. Even when using inorganic compounds or polymer compounds (oligomers, dendrimers, polymers, etc.) good.

[0228] The configuration shown in this embodiment can be used in appropriate combination with the configurations shown in other embodiments. It is possible to be there.

[0229] (Embodiment 3) In this embodiment, a configuration different from the configurations shown in Embodiments 1 and 2 is generated. The optical element and the light-emitting mechanism of the light-emitting element will be explained below with reference to Figures 5 and 6. Furthermore, in Figures 5 and 6, parts that have the same function as those shown in Figure 1(A) are indicated by the following symbols: The same hatch pattern may be used, and the symbols may be omitted. Also, areas with similar functions. Similar symbols are used, and detailed explanations may be omitted.

[0230] <Example of light-emitting element configuration 1> Figure 5(A) is a schematic cross-sectional view of the light-emitting element 250.

[0231] The light-emitting element 250 shown in Figure 5(A) has a pair of electrodes (electrode 101 and electrode 102) between them. , multiple light-emitting units (in Figure 5(A), light-emitting unit 106 and light-emitting unit 1 08) has. One of the multiple light-emitting units is shown in Figure 1(A) It is preferable that it has a similar configuration to the EL layer 100 shown in Figure 1(A). In other words, the light emission shown in Figure 1(A) Element 150 has one light-emitting unit, and light-emitting element 250 has multiple light-emitting units. This is preferable. In the light-emitting element 250, the electrode 101 functions as an anode, and the electrode Assuming that 102 functions as the cathode, the following explanation will describe the configuration of the light-emitting element 250. It's fine the other way around too.

[0232] Furthermore, in the light-emitting element 250 shown in Figure 5(A), the light-emitting unit 106 and the light-emitting unit 108 is stacked, and between the light-emitting unit 106 and the light-emitting unit 108 there is an electric current A bio-layer 115 is provided. Note that the light-emitting unit 106 and the light-emitting unit 108 have the same configuration. However, a different configuration is also acceptable. For example, the light-emitting unit 108 may have the EL layer 10 shown in Figure 1(A) Using 0 is preferable.

[0233] Furthermore, the light-emitting element 250 has a light-emitting layer 120 and a light-emitting layer 130. In addition to the light-emitting layer 120, knit 106 also includes a hole injection layer 111, a hole transport layer 112, and an electron transport layer. It has a layer 113 and an electron injection layer 114. The light-emitting unit 108 also has a light-emitting layer 130 In addition, there is a hole injection layer 116, a hole transport layer 117, an electron transport layer 118, and an electron injection layer 11 It has 9.

[0234] The charge generation layer 115 is a hole transport material to which an acceptor substance, which is an electron acceptor, is added. Even with such a configuration, the electron transport material is combined with a donor substance that acts as an electron donor. This is also acceptable. Furthermore, both of these configurations may be stacked.

[0235] If the charge generation layer 115 contains a composite material of an organic compound and an acceptor substance, The composite material used is a composite material that can be used in the hole injection layer 111 shown in Embodiment 1. That's all. As for organic compounds, aromatic amine compounds, carbazole compounds, aromatic carbon compounds Various compounds are used, such as hydrogen and polymer compounds (oligomers, dendrimers, polymers, etc.). It can exist. Furthermore, as an organic compound, its hole mobility is 1 × 10⁻⁶. -6 cm 2 / Vs It is preferable to use a material that meets the above criteria. However, a material that has higher hole transport than electron transport. In that case, other substances may be used. Composite materials of organic compounds and acceptor substances. Because the material has excellent carrier injection and carrier transport properties, it enables low-voltage and low-current operation. It can be shown. Furthermore, as with the light-emitting unit 108, the anode side surface of the light-emitting unit is When in contact with the charge generation layer 115, the charge generation layer 115 is the hole injection layer of the light-emitting unit. Alternatively, it can also serve as a hole transport layer, so the light-emitting unit may have a hole injection layer or A hole transport layer is not required.

[0236] Furthermore, the charge generation layer 115 is a layer containing a composite material of an organic compound and an acceptor substance, and other It may be formed as a laminated structure by combining layers made of the following materials. For example, organic A layer containing a composite material of a compound and an acceptor substance, and one selected from among electron-donating substances. A layer containing the compound and a compound with high electron transport properties may be formed by combining them. A layer containing a composite material of an organic compound and an acceptor substance, and a layer containing a transparent conductive material are combined. They may be formed by combining them.

[0237] Furthermore, the charge generation layer 115 sandwiched between the light-emitting unit 106 and the light-emitting unit 108 is electric When a voltage is applied to electrode 101 and electrode 102, electrons are injected into one of the light-emitting units. Any method that injects holes into the other light-emitting unit is acceptable. For example, in Figure 5(A), When a voltage is applied such that the potential of electrode 101 is higher than the potential of electrode 102, The charge generation layer 115 injects electrons into the light-emitting unit 106 and holes into the light-emitting unit 108. Enter.

[0238] Furthermore, the charge generation layer 115 has light transmission to visible light (specifically) from the viewpoint of light extraction efficiency. It is preferable that the charge generation layer 115 has a visible light transmittance of 40% or more. Furthermore, the charge generation layer 115 has lower conductivity than the pair of electrodes (electrode 101 and electrode 102). It will still function. If the conductivity of the charge generation layer 115 is as high as that of the pair of electrodes, the charge The carriers generated by the generation layer 115 flow in the direction of the film surface, causing the electrodes 101 and the electrodes to flow together. In some cases, light emission may occur in areas that do not overlap with 102. This defect can be suppressed. For this purpose, the charge generation layer 115 is preferably formed of a material with lower conductivity than the pair of electrodes. It's nice.

[0239] By forming the charge generation layer 115 using the materials described above, the light-emitting layer is stacked in the field This can suppress the rise in drive voltage during operation.

[0240] Furthermore, Figure 5(A) illustrates a light-emitting element having two light-emitting units. However, the same principle can also be applied to light-emitting devices that have three or more light-emitting units stacked on top of each other. As shown in the light-emitting element 250, multiple light-emitting units are placed between a pair of electrodes in a charge generation layer. By partitioning and arranging the elements, high-brightness light emission is possible while maintaining a low current density, and further This enables the creation of light-emitting elements with a long lifespan. Furthermore, it enables the creation of light-emitting elements with low power consumption. .

[0241] Furthermore, of the multiple units, at least one unit has the EL layer shown in Figure 1(A). By applying the 100 configuration, it is possible to provide a light-emitting element with high luminescence efficiency. ru.

[0242] Furthermore, the light-emitting layer 130 of the light-emitting unit 108 has the configuration shown in Embodiment 1. It is preferable that the light-emitting element 250 has a fluorescent material as the light-emitting material and This is preferable as it becomes a light-emitting element with high luminescence efficiency.

[0243] Furthermore, the light-emitting layer 120 of the light-emitting unit 106 is, for example, as shown in Figure 5(B). The device comprises a host material 121 and a guest material 122. The guest material 122 is a fluorescent material. The fees are explained below.

[0244] ≪Light-emitting mechanism of light-emitting layer 120≫ The light-emitting mechanism of the light-emitting layer 120 will be explained below.

[0245] Electrons injected from a pair of electrodes (electrode 101 and electrode 102) or a charge generation layer Excitons are generated when holes recombine in the light-emitting layer 120. Guest material 1 Since there is a large amount of host material 121 compared to 22, the host material is generated by exciton production. An excited state of material 121 is formed.

[0246] An exciton is a carrier (electron and hole) pair. An exciton has energy. Therefore, the material from which excitons are generated enters an excited state.

[0247] If the excited state of the formed host material 121 is a singlet excited state, then the host material 12 Singlet excitation energy is transferred from the S1 level of material 1 to the S1 level of guest material 122. Then, a singlet excited state is formed in guest material 122.

[0248] Since guest material 122 is a fluorescent material, the singlet excited state in guest material 122 Once formed, the guest material 122 rapidly emits light. At this time, to obtain high luminescence efficiency... Therefore, it is preferable that the fluorescence quantum yield of guest material 122 is high. The same applies in case 2, when carriers recombine and the resulting excited state is a singlet excited state. That is the case.

[0249] Next, when a triplet excited state of the host material 121 is formed by carrier recombination... This will be explained. The energy levels of the host material 121 and guest material 122 in this case. The correlation of the ranks is shown in Figure 5(C). The notation and symbols in Figure 5(C) are as follows: Furthermore, the T1 level of the host material 121 is lower than the T1 level of the guest material 122. Since this is preferable, Figure 5(C) illustrates this case, but the T1 level of the host material 121 This may be higher than the T1 level of guest material 122.

[0250] • Host(121): Host material 121 • Guest (122): Guest material 122 (fluorescent material) ·S FH : S1 level of host material 121 ·T FH :T1 level of host material 121 ·S FG : S1 level of guest material 122 (fluorescent material) ·T FG : T1 level of guest material 122 (fluorescent material)

[0251] As shown in Figure 5(C), triplet excitons generated by carrier recombination are in close proximity to each other. By transferring excitation energy and exchanging spin angular momentum, as a result, one side The S1 level of the host material 121 (S FH It is converted into a singlet exciton having the energy of ). This is a triplet-triplet annihilation reaction (TTA). Nihilation occurs (see Figure 5(C) TTA). Single layer of host material 121. The excitation energy of the term is S FH Therefore, guest material 122 S1 has lower energy than that. Level (S FG Energy transfer occurs to (see Route E1 in Figure 5(C)), and guest material 1 22 singlet excited states are formed, and guest material 122 emits light.

[0252] Furthermore, if the density of triplet excitons in the light-emitting layer 120 is sufficiently high (for example, 1 × 10⁻¹⁰ -12 cm -3 (The above) ignores the deactivation of a single triplet exciton and considers two closely spaced triplet excitons. We can consider only the reaction caused by the initiator.

[0253] Furthermore, when carriers recombine in guest material 122 and a triplet excited state is formed... The triplet excited state of guest material 122 is thermally deactivated, making it difficult to utilize for luminescence. However, the T1 level (T) of the host material 121 FH ) is a guest material 122 T1 standard Place(T FG If it is lower than ), the triplet excitation energy of guest material 122 is, 22 T1 levels (T FG ) from the T1 level of host material 121 (T FH Energy transfer to ) It is possible to do this (see Figure 5(C) Route E2), and it is then used for TTA.

[0254] In other words, the host material 121 has a triplet excitation energy, and a singlet excitation energy, which is obtained by TTA. It is preferable that it has the function of converting into energy. By doing so, the light generated in the light-emitting layer 120 A portion of the triplet excitation energy is obtained by singlet excitation energy in the host material 121 via TTA. By converting it into energy and transferring the singlet excitation energy to the guest material 122, fluorescence It becomes possible to extract it as luminescence. To do this, the S1 level (S) of the host material 121 is required. FH ) is the S1 level (S FG It is preferable that it is higher than ) Also, phos T1 level of material 121 (T FH ) is the T1 level of guest material 122 (T FG ) lower It is preferable.

[0255] In particular, the T1 level of guest material 122 (T FG ) is the T1 level (T FH If it is lower than ), the weight ratio of host material 121 to guest material 122 is, A lower weight ratio of guest material 122 is preferable. Specifically, a lower weight ratio of the guest material 122 relative to the host material 121. The weight ratio of guest material 122 is preferably greater than 0 and 0.05 or less. This reduces the probability of carrier recombination with guest material 122. T1 level of host material 121 (T FH ) from guest material 122 T1 level (T FG ) to This can reduce the probability of energy transfer occurring.

[0256] The host material 121 may be composed of a single compound, or it may be composed of multiple compounds. It's fine if it's done.

[0257] In addition, in each of the above configurations, the luminescent unit 106 and the luminescent unit 108 are used The fluorescent material may be the same or different. Light-emitting unit 10 If the light-emitting unit 108 and 6 have the same guest material, the light-emitting element 250 will have a lower current. It is preferable to have a light-emitting element that exhibits high luminous brightness at a given value. When knit 108 has different guest materials, the light-emitting element 250 exhibits multicolor emission. It is preferable to use it as an optical element. In particular, it emits white light with high color rendering, or at least red and green light. It is preferable to select guest materials such that they emit light that has a blue color.

[0258] If the light-emitting unit 106 and the light-emitting unit 108 have different guest materials, the light-emitting layer The emission from 120 has an emission peak at a shorter wavelength than the emission from the light-emitting layer 130. It is preferable to have this configuration. Light-emitting devices using materials with high triplet excited states suffer from brightness degradation. This tends to be faster. Therefore, by using TTA in the light-emitting layer that exhibits short-wavelength emission... This makes it possible to provide a light-emitting element with minimal brightness degradation.

[0259] <Example of light-emitting element configuration 2> Figure 6(A) is a schematic cross-sectional view of the light-emitting element 252.

[0260] The light-emitting element 252 shown in Figure 6(A) is similar to the light-emitting element 250 shown earlier, and consists of a pair of electrodes. Between electrodes 101 and 102, there are multiple light-emitting units (in Figure 6(A), It has a light unit 106 and a light-emitting unit 110). One light-emitting unit is shown in Figure 4(A It is preferable that the EL layer 100 shown in ) has a similar configuration. The optical unit 110 may have the same configuration or a different configuration.

[0261] Furthermore, in the light-emitting element 252 shown in Figure 6(A), the light-emitting unit 106 and the light-emitting unit 110 and are stacked, and between the light-emitting unit 106 and the light-emitting unit 110 there is an electric current A raw layer 115 is provided. For example, the light-emitting unit 110 has an EL layer 10 as shown in Figure 4(A) Using 0 is preferable.

[0262] Furthermore, the light-emitting element 252 has a light-emitting layer 120 and a light-emitting layer 140. In addition to the light-emitting layer 120, knit 106 also includes a hole injection layer 111, a hole transport layer 112, and an electron transport layer. It has a layer 113 and an electron injection layer 114. The light-emitting unit 110 also has a light-emitting layer 140 In addition, there is a hole injection layer 116, a hole transport layer 117, an electron transport layer 118, and an electron injection layer 11 It has 9.

[0263] Furthermore, it is preferable that the light-emitting layer of the light-emitting unit 110 has a phosphorescent material. The light-emitting layer 120 of unit 106 has the configuration shown in Configuration Example 1 of this embodiment, The light-emitting layer 140 of the light-emitting unit 110 preferably has the configuration shown in Embodiment 2. That is the case.

[0264] Furthermore, the light emitted from the light-emitting layer 120 has a shorter wavelength peak than the light emitted from the light-emitting layer 140. It is preferable to have a configuration that has a luminescent element. The child tends to experience rapid brightness degradation. Therefore, by using fluorescence emission for short-wavelength emission, This makes it possible to provide a light-emitting element with minimal brightness degradation.

[0265] Furthermore, by obtaining light of different emission wavelengths from the light-emitting layer 120 and the light-emitting layer 140, multicolor It can be used as a light-emitting element. In this case, the emission spectrum will have different emission peaks. Since the emitted light is a composite of light, the emission spectrum will have at least two maxima. .

[0266] Furthermore, the above configuration is also suitable for obtaining white light emission. Light-emitting layer 120 and light-emitting layer 140 By making the light and the light complementary to each other, white light emission can be obtained.

[0267] Furthermore, one or both of the light-emitting layers 120 and 140 may have multiple emission wavelengths. By using multiple luminescent materials, it is possible to produce highly color-rendering colors consisting of the three primary colors or four or more luminescent colors. White light emission can also be obtained. In this case, either the light-emitting layer 120 or the light-emitting layer 140. Alternatively, both can be further divided into layers, and each divided layer can contain a different light-emitting material. You can do that too.

[0268] <Example of light-emitting element configuration 3> Figure 6(B) is a schematic cross-sectional view of the light-emitting element 254.

[0269] The light-emitting element 254 shown in Figure 6(B) is similar to the light-emitting element 250 shown earlier, and consists of a pair of electrodes. Between electrodes 101 and 102, there are multiple light-emitting units (in Figure 6(B), It has a light unit 109 and a light-emitting unit 110). Among the multiple light-emitting units, at least Both light-emitting units have a configuration similar to the EL layer 100 shown in Figure 1(A), and the other unit The light-emitting unit preferably has a configuration similar to that of the EL layer 100 shown in Figure 4(A).

[0270] Furthermore, in the light-emitting element 254 shown in Figure 6(B), the light-emitting unit 109 and the light-emitting unit 110 and are stacked, and between the light-emitting unit 109 and the light-emitting unit 110 there is an electric current A raw layer 115 is provided. For example, the light-emitting unit 109 has an EL layer 10 as shown in Figure 1(A) Using a configuration similar to that of 0, the light-emitting unit 110 is provided with a configuration similar to that of the EL layer 100 shown in Figure 4(A). Using a configuration is preferable.

[0271] Furthermore, the light-emitting element 254 has a light-emitting layer 130 and a light-emitting layer 140. Knit 109, in addition to the light-emitting layer 130, includes a hole injection layer 111, a hole transport layer 112, and an electron transport layer. It has a layer 113 and an electron injection layer 114. The light-emitting unit 110 also has a light-emitting layer 140 In addition, there is a hole injection layer 116, a hole transport layer 117, an electron transport layer 118, and an electron injection layer 11 It has 9.

[0272] In other words, the light-emitting layer 130 of the light-emitting unit 109 has the configuration shown in Embodiment 1. The light-emitting layer 140 of the light-emitting unit 110 has the configuration shown in Embodiment 2. This is preferable.

[0273] Furthermore, the emission from the light-emitting layer 130 has a shorter wavelength peak than the emission from the light-emitting layer 140. It is preferable to have a configuration that has a luminescent element. The child tends to experience rapid brightness degradation. Therefore, by using fluorescence emission for short-wavelength emission, This makes it possible to provide a light-emitting element with minimal brightness degradation.

[0274] Furthermore, by obtaining light of different emission wavelengths from the light-emitting layer 130 and the light-emitting layer 140, multicolor It can be used as a light-emitting element. In this case, the emission spectrum will have different emission peaks. Since the emitted light is a composite of light, the emission spectrum will have at least two maxima. .

[0275] Furthermore, the above configuration is also suitable for obtaining white light emission. Light-emitting layer 130 and light-emitting layer 140 By making the light and the light complementary to each other, white light emission can be obtained.

[0276] Furthermore, one or both of the light-emitting layers 130 and 140 may have multiple emission wavelengths. By using multiple luminescent materials, it is possible to produce highly color-rendering colors consisting of the three primary colors or four or more luminescent colors. White light emission can also be obtained. In this case, either the light-emitting layer 130 or the light-emitting layer 140 Alternatively, both can be further divided into layers, and each divided layer can contain a different light-emitting material. You can do that too.

[0277] <Examples of materials that can be used for the light-emitting layer> Next, regarding the materials that can be used for the light-emitting layer 120, light-emitting layer 130, and light-emitting layer 140... I will explain below.

[0278] <<Materials that can be used for the light-emitting layer 120>> In the light-emitting layer 120, the host material 121 is the most abundant by weight, followed by the guest material 122 The (fluorescent material) is dispersed in the host material 121. The S1 level of the host material 121 is The T1 level of host material 121 is higher than the S1 level of host material 122 (fluorescent material), It is preferable that the level is lower than the T1 level of the fluorescent material 122.

[0279] In the light-emitting layer 120, there are no particular limitations on the guest material 122, but for example, The material exemplified as guest material 132 shown in Embodiment 1 can be used.

[0280] Furthermore, in the light-emitting layer 120, the materials that can be used for the host material 121 are: There are no particular limitations, but for example, tris(8-quinolinolato)aluminum(III) (abbreviation) :Alq), Tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq3), bis(10-hydroxybenzo[h]quinolinato)beryllium(II) Abbreviation: BeBq2), bis(2-methyl-8-quinolinolate)(4-phenylphenolate ) Aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (Abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolate]zinc(II) Abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phenolate]zinc(II) Metal complexes such as (abbreviated as ZnBTZ), 2-(4-biphenylyl)-5-(4-tert- Butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5 -(p-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]ben Zen (abbreviation: OXD-7), 3-(4-biphenylyl)-4-phenyl-5-(4-te rt-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 2,2',2' -(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzoimidazo Vasophenanthroline (abbreviation: TPBI), Vasophenanthroline (abbreviation: BPhen), Vasocuproline (Abbreviation: BCP), 9-[4-(5-phenyl-1,3,4-oxadiazole-2- Heterocyclic compounds such as yl(phenyl)-9H-carbazole (abbreviation: CO11), 4,4 '-Bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB) (α-NPD), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1 ,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4'-bis[N-( Spiro-9,9'-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation) Examples include aromatic amine compounds such as BSPB. Also, anthracene derivatives, ferrous compounds, etc. Nanthrene derivatives, pyrene derivatives, chrysene derivatives, dibenzo[g,p]chrysene derivatives Examples include condensed polycyclic aromatic compounds such as 9,10-diphenylanthracene (Abbreviation: DPAnth), N,N-diphenyl-9-[4-(10-phenyl-9-Anth) Tolyl)phenyl]-9H-carbazole-3-amine (abbreviation: CzA1PA), 4-( 10-phenyl-9-anthryl)triphenylamine (abbreviation: DPhPA), 4-(9 H-carbazole-9-yl)-4'-(10-phenyl-9-anthryl)triphenyl Luamine (abbreviation: YGAPA), N,9-diphenyl-N-[4-(10-phenyl-9 -Anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: PCAPA), N ,9-diphenyl-N-{4-[4-(10-phenyl-9-antryl)phenyl]f phenyl-9H-carbazole-3-amine (abbreviation: PCAPBA), N,9-diphenyl ru-N-(9,10-diphenyl-2-anthryl)-9H-carbazole-3-amine (Abbreviation: 2PCAPA), 6,12-dimethoxy-5,11-diphenylchrysene, N, N,N',N',N'',N'',N''',N'''-Octaphenyldibenzo[g, p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), 9-[4-(1 O-phenyl-9-antryl)phenyl]-9H-carbazole (abbreviation: CzPA), 3,6-diphenyl-9-[4-(10-phenyl-9-antryl)phenyl]-9H -Carbazole (abbreviation: DPCzPA), 9,10-bis(3,5-diphenylphenyl )Anthracene (abbreviation: DPPA), 9,10-di(2-naphthyl)anthracene (abbreviation :DNA), 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation) :t-BuDNA), 9,9'-biantril (abbreviation: BANT), 9,9'-(still Ben-3,3'-diphenylenanthren (abbreviation: DPNS), 9,9'-(Stilbe n-4,4'-diyl)diphenanthrene (abbreviation: DPNS2), 1,3,5-tri(1 Examples include pyrenyl benzene (abbreviated as TPB3). Furthermore, these and From among known materials, an energy greater than the energy gap of the above guest material 122 You can use one or more materials that have gaps.

[0281] The light-emitting layer 120 can also be composed of two or more layers. For example, the first When the first light-emitting layer and the second light-emitting layer are stacked in order from the hole transport layer side to form the light-emitting layer 120, A material having hole transport properties is used as the host material for the first light-emitting layer, and the host material for the second light-emitting layer One such configuration involves using materials that possess electron-transporting properties.

[0282] Furthermore, in the light-emitting layer 120, the host material 121 is composed of a certain compound. It is also fine if it is composed of multiple compounds. Alternatively, in the light-emitting layer 120, It may also contain materials other than stock material 121 and guest material 122.

[0283] <<Materials that can be used for the light-emitting layer 130>> Materials that can be used for the light-emitting layer 130 include the light-emitting layer 13 shown in Embodiment 1 above. You can use materials that can be used for 0. By doing so, you can generate singlet excited states. It is possible to fabricate light-emitting devices with high efficiency and high luminous efficiency.

[0284] <<Materials that can be used for the light-emitting layer 140>> As for materials that can be used for the light-emitting layer 140, the light-emitting layer 14 shown in Embodiment 2 above is an example. You can use materials that can be used for 0. In that case, light-emitting elements with low driving voltage It can produce offspring.

[0285] Furthermore, the emission color of the light-emitting material contained in the light-emitting layer 120, light-emitting layer 130, and light-emitting layer 140 There are no limitations; they can be the same or different. The light emitted from each is mixed. Since it is extracted outside the element, for example, if the light emitted by both is complementary to each other, the light-emitting element The child can emit white light. Considering the reliability of the light-emitting element, the light-emitting layer 120 is included The emission peak wavelength of the luminescent material contained in emission layer 130 and emission layer 140 is the luminescent material It is preferable that it be shorter than that.

[0286] Note that the light-emitting unit 106, light-emitting unit 108, light-emitting unit 109, light-emitting unit 110 and the charge generation layer 115 are manufactured by vapor deposition (including vacuum deposition), inkjet, and coating. It can be formed by methods such as weaving or gravure printing.

[0287] The configuration shown in this embodiment can be used in appropriate combination with the configurations shown in other embodiments. It is possible to be there.

[0288] (Embodiment 4) In this embodiment, the light-emitting element has a configuration different from that shown in Embodiments 1 to 3. An example of this will be explained below using Figures 7 to 10.

[0289] <Example of light-emitting element configuration 1> Figures 7(A) and 7(B) are cross-sectional views showing a light-emitting element according to one embodiment of the present invention. In (B), the same hatching is used in areas that have the same function as the symbols shown in Figure 1(A). In some cases, the code may be omitted as a pattern. Also, similar functions are used in similar places. Symbols may be used, and detailed explanations may be omitted.

[0290] The light-emitting elements 260a and 260b shown in Figures 7(A) and 7(B) are connected to the substrate 200 side. It may also be a bottom-emission type light-emitting element that extracts from the substrate 200 and It may also be a top-emission type light-emitting element that extracts light in the opposite direction. However, one aspect of the present invention is not limited thereto, and the light emitted by the light-emitting element is directed above the substrate 200. It may also be a dual-emission type light-emitting element that emits light from both the upper and lower sides. .

[0291] When the light-emitting element 260a and light-emitting element 260b are of the bottom emission type, electrode 1 Preferably, 01 has the function of transmitting light. Also, electrode 102 reflects light. It is preferable that the light-emitting element 260a and the light-emitting element 260b have a function. In the case of a top-emission type, it is preferable that the electrode 101 has the function of reflecting light. Furthermore, it is preferable that the electrode 102 has the function of transmitting light.

[0292] The light-emitting element 260a and the light-emitting element 260b have an electrode 101 and an electrode 102 on the substrate 200. It has the following: In addition, between electrode 101 and electrode 102, there is a light-emitting layer 123B and a light-emitting layer 123 It has G and a light-emitting layer 123R. It also has a hole injection layer 111 and a hole transport layer 112. It has an electron transport layer 118 and an electron injection layer 119.

[0293] Furthermore, the light-emitting element 260b is part of the configuration of the electrode 101, and the conductive layer 101a and the conductive It has a conductive layer 101b on layer 101a and a conductive layer 101c below the conductive layer 101a. In other words, the light-emitting element 260b has a conductive layer 101a, a conductive layer 101b, and a conductive layer 101c. It has a configuration of clamped electrodes 101.

[0294] In the light-emitting element 260b, the conductive layer 101b and the conductive layer 101c are made of different materials. It may be done in this way, or it may be formed from the same material. The electrode 101 may have the same conductive layer 101a. When the structure is sandwiched between electrolytic materials, pattern formation by etching becomes easier. Therefore, it is preferable.

[0295] Furthermore, in the light-emitting element 260b, in the conductive layer 101b or the conductive layer 101c, A configuration having only one of the two offsets is also acceptable.

[0296] Furthermore, the conductive layers 101a, 101b, and 101c of the electrode 101 are each implemented The same configuration and materials as those used for electrode 101 or electrode 102 shown in Form 1 can be used. Cut.

[0297] In Figures 7(A) and 7(B), the region 221B is sandwiched between electrode 101 and electrode 102. A partition wall 145 is located between region 221G and region 221R. The partition wall 145 provides insulation. The partition wall 145 covers the end of the electrode 101 and has an opening that overlaps with the electrode. By providing 145, the electrodes 101 on the substrate 200 in each region are separated into island-like structures. It becomes possible to separate them.

[0298] Furthermore, in the region where the light-emitting layer 123B and the light-emitting layer 123G overlap with the partition wall 145, It may have an overlapping region. Also, the light-emitting layer 123G and the light-emitting layer 123R are separated by a distance. In the region overlapping with wall 145, there may be overlapping regions with each other. Also, the light-emitting layer 1 23R and the light-emitting layer 123B overlap with the partition wall 145, and the overlapping regions of each other It is acceptable to have it.

[0299] The partition wall 145 only needs to be insulating and is formed using an inorganic or organic material. The inorganic materials include silicon oxide, silicon oxide nitride, silicon nitride oxide, silicon nitride silicon Examples of organic materials include aluminum oxide, aluminum nitride, etc. Examples include photosensitive resin materials such as acrylic resin or polyimide resin.

[0300] Furthermore, a silicon oxidizride film is a film whose composition contains more oxygen than nitrogen. Preferably, oxygen is 55 atomic% or more and 65 atomic% or less, and nitrogen is 1 atomic% or more and 20 atomic%. Below, silicon is 25 atomic% to 35 atomic%, and hydrogen is 0.1 atomic% to 10 atomic%. This refers to items included in the following range. A silicon nitride film, in terms of its composition, contains more oxygen than... This refers to a membrane with a high nitrogen content, preferably containing 55 atomic% to 65 atomic% nitrogen and oxygen. 1 atomic% to 20 atomic%, silicon 25 atomic% to 35 atomic%, hydrogen 0.1 This refers to substances that are present in a concentration range of 10% to 10 atomic percent.

[0301] Furthermore, the light-emitting layer 123R, light-emitting layer 123G, and light-emitting layer 123B each exhibit different colors. It is preferable to have a light-emitting material that has the function of emitting red light. For example, the light-emitting layer 123R exhibits red light. By having a light-emitting material that has the function of, region 221R exhibits red light emission, and light-emitting layer 12 Region 221G emits green light because region 3G has a light-emitting material that exhibits a green light. The light-emitting layer 123B has a light-emitting material that exhibits a blue color, thus region 221 B emits blue light. A light-emitting element 260a or light-emitting element 26 has such a configuration. By using 0b as the pixel of the display device, a display device capable of full-color display can be manufactured. This is possible. Also, the film thickness of each light-emitting layer may be the same or different. good.

[0302] Additionally, one or more of the light-emitting layers 123B, 123G, and 123R. The light-emitting layer is the light-emitting layer 130 shown in Embodiment 1 and the light-emitting layer 14 shown in Embodiment 2. It is preferable to have at least one of 0. By doing so, a good luminescence efficiency is achieved. Optical devices can be fabricated.

[0303] Note that one or more of the light-emitting layers 123B, 123G, and 123R may be present. The light-emitting layer may be configured with two or more layers stacked on top of each other.

[0304] As described above, at least one light-emitting layer is the light-emitting layer shown in Embodiment 1 or Embodiment 2. A light-emitting element 260a or 260b having a light-emitting layer is used in a display device. By using it in pixels, it is possible to create a display device with high luminescence efficiency. A display device having element 260a or light-emitting element 260b can reduce power consumption. Cut.

[0305] Furthermore, in the direction from which light is extracted from the electrode that extracts light, an optical element (for example, a color filter) is placed. By providing polarizing plates, anti-reflective coatings, etc., the color purity of the light-emitting element 260a and the light-emitting element 260b is improved. The degree can be improved. Therefore, the light-emitting element 260a or light-emitting element 260b The color purity of the display device can be improved. Alternatively, the light-emitting element 260a and the light-emitting element can be improved. External light reflection of 260b can be reduced. Therefore, the light-emitting element 260a or light-emitting element The contrast ratio of a display device having sub-element 260b can be increased.

[0306] Furthermore, other configurations of the light-emitting element 260a and light-emitting element 260b are as follows: The configuration of the light-emitting element in Embodiments 1 to 3 should be taken into consideration.

[0307] <Example of light-emitting element configuration 2> Next, Figures 8(A) and 8(B) show examples of configurations different from the light-emitting elements shown in Figures 7(A) and 7(B). We will use this to provide the following explanation.

[0308] Figures 8(A) and 8(B) are cross-sectional views showing a light-emitting element according to one embodiment of the present invention. In (B), the same symbols are used for parts that have the same function as those shown in Figures 7(A) and (B). A hatch pattern may be used, and the symbols may be omitted. Also, in areas with similar functions, Similar symbols may be used, and their detailed explanations may be omitted.

[0309] Figures 8(A) and 8(B) show examples of the configuration of a light-emitting element having a light-emitting layer between a pair of electrodes. The light-emitting element 262a shown in (A) is an upper-surface emitter that extracts light in the direction opposite to the substrate 200. The light-emitting element of the (up-emission) type, the light-emitting element 262b shown in Figure 8(B), is on the substrate 200 side. This is a bottom-emission type light-emitting element that extracts light from the bottom. One embodiment is not limited thereto, and the light emitted by the light-emitting element is on the substrate 200 on which the light-emitting element is formed. It may also be a dual-emission type that extracts material from both the front and the bottom.

[0310] The light-emitting element 262a and the light-emitting element 262b have an electrode 101 and an electrode 102 on the substrate 200. It has electrode 103 and electrode 104. Also, between electrode 101 and electrode 102, At least light is emitted between electrode 102 and electrode 103, and between electrode 102 and electrode 104. It has a layer 170 and a charge generation layer 115. It also has a hole injection layer 111 and a hole transport layer 11 2, the light-emitting layer 180, the electron transport layer 113, the electron injection layer 114, and the hole injection layer 116 It has a hole transport layer 117, an electron transport layer 118, and an electron injection layer 119.

[0311] Furthermore, the electrode 101 consists of a conductive layer 101a and a conductive layer 101b that is in contact with the conductive layer 101a. , has . Furthermore, electrode 103 has a conductive layer 103a and a conductive layer in contact with the conductive layer 103a 103b and Electrode 104 has a conductive layer 104a and a conductive layer in contact with the conductive layer 104a. It has an electrolytic layer 104b.

[0312] The light-emitting element 262a shown in Figure 8(A) and the light-emitting element 262b shown in Figure 8(B) are electrodes Region 222B sandwiched between electrode 101 and electrode 102, sandwiched between electrode 102 and electrode 103 Between region 222G and region 222R sandwiched between electrode 102 and electrode 104, It has a wall 145. The partition wall 145 is insulating. The partition wall 145 has electrodes 101 and 1 A partition wall 145 is provided, which covers the ends of electrode 104 and has an opening that overlaps with the electrode. By doing so, it becomes possible to separate the electrodes on the substrate 200 in each region into island-like structures. This is the result.

[0313] Furthermore, the light-emitting element 262a and the light-emitting element 262b are located in region 222B, region 222G, and In the direction from which the light emitted from region 222R is extracted, the optical element 224B and the optical element are respectively positioned. The substrate 220 has a sub-element 224G and an optical element 224R. Light emitted from each region It is emitted to the outside of the light-emitting element through each optical element. That is, it is emitted from region 222B. The light is emitted through the optical element 224B, and the light emitted from region 222G is emitted through the optical element The light emitted through 224G and emanating from region 222R is transmitted through optical element 224R. It is launched.

[0314] Furthermore, optical elements 224B, 224G, and 224R receive incident light It has the function of selectively transmitting light exhibiting a specific color. For example, optical element 224B The light emitted from region 222B through the optical element 22 becomes blue light. The light emitted from region 222G via 4G becomes green light, and the optical element The light emitted from region 222R via sub-element 224R is red in color.

[0315] Optical elements 224R, 224G, and 224B include, for example, a colored layer ( Color filters (also called color filters), bandpass filters, and multilayer filters can be applied. Furthermore, a color conversion element can be applied to an optical element. The color conversion element converts the incident light to... This is an optical element that converts light to wavelengths longer than the wavelength of the light in question. It uses quantum dots as color conversion elements. It is preferable that the element uses quantum dots. By using quantum dots, the color reproducibility of the display device is improved. It can improve.

[0316] Furthermore, other optical elements may be placed on optical elements 224R, 224G, and 224B. One or more of these may be arranged in a stack. Other optical elements include, for example, circular polarizers and anti-reflective coatings. A protective film can be provided. The circular polarizing plate is used to extract light emitted from the light-emitting element of the display device. When placed on the receiving side, light incident from outside the display device is reflected inside the display device, and the outside This prevents the phenomenon of ejection from the part. In addition, by providing an anti-reflective coating, the surface of the display device This can reduce the amount of ambient light reflected by the device. This makes the light emitted by the display device clearer. It can be observed.

[0317] In Figures 8(A) and 8(B), the light emitted from each region through each optical element is referred to as blue. Let light exhibiting color (B), light exhibiting green (G), and light exhibiting red (R) be defined as follows: This is schematically illustrated with dashed arrows.

[0318] Furthermore, a light-shielding layer 223 is provided between each optical element. The light-shielding layer 223 is provided in adjacent regions or It has the function of blocking the light emitted from it. Furthermore, a configuration without the light-blocking layer 223 is also acceptable. stomach.

[0319] The light-shielding layer 223 has the function of suppressing the reflection of external light. Alternatively, the light-shielding layer 223 and Therefore, it has the function of preventing the mixing of colors of light emitted from adjacent light-emitting elements. Light-shielding layer 223 and For example, metals, resins containing black pigments, carbon black, metal oxides, and multiple metal oxides. A composite oxide containing a solid solution of a substance can be used.

[0320] Furthermore, in the region where optical element 224B and optical element 224G overlap with the light-shielding layer 223 They may have overlapping regions. Alternatively, optical element 224G and optical element 2 24R refers to a region that overlaps with the light-shielding layer 223, and may have overlapping regions with each other. Alternatively, optical element 224R and optical element 224B are in a region that overlaps with the light-shielding layer 223. In this context, it is acceptable for them to have overlapping regions.

[0321] Furthermore, the substrate 200 and the substrate 220 having optical elements should be considered in reference to Embodiment 1. That's all you need to do.

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

[0323] <<Microcavity structure>> Light emitted from the light-emitting layer 170 and the light-emitting layer 180 is directed towards a pair of electrodes (for example, electrode 10 Resonance occurs between 1 and electrode 102). Also, the light-emitting layer 170 and light-emitting layer 180 are emitted. It is formed at a position where the light of a desired wavelength is intensified among the incoming light. For example, in the reflection region of electrode 101 The optical distance from the light-emitting region of the light-emitting layer 170 to the optical distance from the reflection region of the electrode 102 to the light-emitting layer 170 By adjusting the optical distance to the light-emitting region, the light emitted from the light-emitting layer 170 can be controlled. This allows for the amplification of light of a desired wavelength. Also, from the reflection region of electrode 101 to the light-emitting layer 180 The optical distance to the light-emitting region and the distance from the reflection region of electrode 102 to the light-emitting region of light-emitting layer 180 By adjusting the optical distance, the desired wavelength of light emitted from the light-emitting layer 180 can be selected. The light can be intensified. That is, multiple light-emitting layers (here, light-emitting layer 170 and light-emitting layer In the case of a light-emitting element that stacks 180), the optical distance between the light-emitting layer 170 and the light-emitting layer 180 is It is preferable to optimize the separation.

[0324] Furthermore, in the light-emitting element 262a and light-emitting element 262b, a conductive layer (conductive layer 1) is present in each region. By adjusting the thickness of 01b, conductive layer 103b, and conductive layer 104b), the light-emitting layer 170 Furthermore, it is possible to enhance the light of a desired wavelength from the light emitted from the light-emitting layer 180. In the region, at least one of the hole injection layer 111 and the hole transport layer 112 has a different thickness. This may enhance the light emitted from the light-emitting layer 170 and the light-emitting layer 180.

[0325] For example, electrodes 101 to 104 are made of a conductive material that has the function of reflecting light. When the refractive index is smaller than the refractive index of the light-emitting layer 170 or the light-emitting layer 180, the electrode The thickness of the conductive layer 101b on 101 is determined by the optical distance between electrode 101 and electrode 102 being m B λ B / 2(m B λ is a natural number, B (These represent the wavelengths of light that are strengthened in region 222B.) Adjust to achieve this. Similarly, the thickness of the conductive layer 103b on electrode 103 is adjusted to match electrode 103 and The optical distance between electrode 102 is m G λ G / 2(m G λ is a natural number, G Stronger in region 222G The wavelengths of light are adjusted to be (represented by). Furthermore, the conductive layer of electrode 104 The film thickness of 104b is such that the optical distance between electrode 104 and electrode 102 is m R λ R / 2(m R is natural number, λ R The wavelengths of light that are strengthened in region 222R are adjusted accordingly.

[0326] Furthermore, if it is difficult to precisely determine the reflection region of electrodes 101 to 104, By assuming that any region of electrode 101 to electrode 104 is a reflective region, the light-emitting layer 170 or The optical distance at which the light emitted from the light layer 180 is strengthened may be derived. Also, the light-emitting layer 170 If it is difficult to precisely determine the light-emitting region of the light-emitting layer 180, the light-emitting layer 170 and By assuming that any region of the light layer 180 is an emission region, the emission layer 170 and the emission layer 180 You may also derive the optical distance at which the light emitted from the source is intensified.

[0327] As described above, a microcavity structure is provided, and the optical distance between the pair of electrodes in each region is adjusted. By optimizing the surface, light scattering and absorption near each electrode are suppressed, resulting in a high light extraction efficiency. This can achieve a certain ratio. In the above configuration, conductive layer 101b, conductive layer 103 b. Preferably, the conductive layer 104b has the function of transmitting light. Also, conductive layer 101 The materials constituting b, conductive layer 103b, and conductive layer 104b may be the same as each other. They may be different. The same material may be used for conductive layer 101b, conductive layer 103b, and conductive layer 104b. Using this material is preferable because it facilitates pattern formation through the etching process. The conductive layer 101b, conductive layer 103b, and conductive layer 104b are each laminated with two or more layers. It is also acceptable to have such a configuration.

[0328] Note that the light-emitting element 262a shown in Figure 8(A) is a top-extrusion type light-emitting element, therefore the conductive layer It is preferable that 101a, conductive layer 103a, and conductive layer 104a have the function of reflecting light. Furthermore, the electrode 102 has both the function of transmitting light and the function of reflecting light. preferable.

[0329] Furthermore, the light-emitting element 262b shown in Figure 8(B) is a bottom-extrusion type light-emitting element, therefore it is conductive Layer 101a, conductive layer 103a, and conductive layer 104a have the function of transmitting light and the function of reflecting light. It is preferable that the electrode 102 has the ability to reflect light. preferable.

[0330] Furthermore, in the light-emitting element 262a and light-emitting element 262b, conductive layer 101a, conductive layer 10 The same material may be used for 3a or the conductive layer 104a, or different materials may be used. When the same material is used for conductive layer 101a, conductive layer 103a, and conductive layer 104a, the light-emitting element The manufacturing costs of the sub-element 262a and the light-emitting element 262b can be reduced. The electrical layer 103a and the conductive layer 104a may each have a configuration in which two or more layers are stacked. stomach.

[0331] Furthermore, the light-emitting layers 170 and 180 in the light-emitting elements 262a and 262b It is preferable that at least one of them has the configuration shown in Embodiment 1 or Embodiment 2. It seems that way. By doing so, it is possible to create light-emitting elements that exhibit high luminescence efficiency.

[0332] Furthermore, the light-emitting layer 170 and the light-emitting layer 180 are, for example, light-emitting layer 180a and light-emitting layer 180b Thus, a configuration in which two layers are stacked on one or both sides may be used. The two light-emitting layers include the first Two types of light-emitting materials, a first light-emitting material and a second light-emitting material, which have the function of exhibiting different colors. By using each of them, it is possible to obtain light emission containing multiple colors. In particular, the light emission layer 170 and The luminescent material used in each luminescent layer is selected so that the luminescence emitted by the luminescent layer 180 results in a white color. Choosing this option is preferable.

[0333] Furthermore, the light-emitting layer 170 or the light-emitting layer 180 is constructed by laminating three or more layers in one or both of them. It may be a composite material, and may also include a layer that does not contain luminescent material.

[0334] As described above, the configuration of the light-emitting layer shown in Embodiment 1 and Embodiment 2 is at least one By using the light-emitting element 262a or light-emitting element 262b as a pixel of a display device, A display device with high light efficiency can be fabricated. That is, the light-emitting element 262a or the light-emitting element A display device having element 262b can reduce power consumption.

[0335] Regarding the other configurations of the light-emitting element 262a and light-emitting element 262b, 260a or light-emitting element 260b, or light-emitting element as shown in Embodiments 1 to 3 You should consider the configuration of the element.

[0336] <Method for fabricating a light-emitting element> Next, a method for manufacturing a light-emitting element according to one aspect of the present invention will be described below using Figures 9 and 10. This section describes the fabrication method for the light-emitting element 262a shown in Figure 8(A). do.

[0337] Figures 9 and 10 are cross-sectional views illustrating a method for manufacturing a light-emitting element according to one embodiment of the present invention. ru.

[0338] The method for fabricating the light-emitting element 262a described below comprises seven steps, from the first to the seventh. ru.

[0339] ≪Step 1≫ The first step is to create electrodes for the light-emitting element (specifically, conductive layers 101 that constitute the electrodes 101). a) conductive layer 103a constituting electrode 103, and conductive layer 104a constituting electrode 104) This is the process of forming it on the substrate 200 (see Figure 9(A)).

[0340] In this embodiment, a conductive layer having the function of reflecting light is formed on the substrate 200. By processing the conductive layer into a desired shape, conductive layer 101a, conductive layer 103a, and conductive Layer 104a is formed. The conductive layer having the function of reflecting light is made of silver and palladium. A copper alloy film (also called Ag-Pd-Cu film or APC) is used. The process of processing the same conductive layer to form the electrical layer 101a, conductive layer 103a, and conductive layer 104a. This method is preferable because it allows for lower manufacturing costs.

[0341] Note that before the first step, multiple transistors may be formed on the substrate 200. Furthermore, the plurality of transistors, conductive layer 101a, conductive layer 103a, and conductive layer 104a They may be electrically connected to each other.

[0342] ≪Step 2≫ The second step is to have a light-transmitting function on the conductive layer 101a that constitutes the electrode 101. A conductive layer 101b is placed on the conductive layer 103a constituting the electrode 103, and has the function of transmitting light. A conductive layer 103b is placed on the conductive layer 104a constituting the electrode 104, and has the function of transmitting light. This is the step of forming the conductive layer 104b (see Figure 9(B)).

[0343] In this embodiment, conductive layers 101a, 103a, and have the function of reflecting light, On 104a, there are conductive layers 101b, 103b, and respectively, which have the function of transmitting light. By forming 104b, electrodes 101, 103, and 104 are formed. ITSO films are used as the conductive layers 101b, 103b, and 104b.

[0344] Furthermore, the conductive layers 101b, 103b, and 104b, which have the function of transmitting light, can be used multiple times. It may be formed in stages. By forming it in stages, suitable microcaches can be formed in each region. The conductive layers 101b, 103b, and 104b can be formed with a film thickness that creates a vitreous structure. Cut.

[0345] ≪Step 3≫ The third step is to form partition walls 145 that cover the ends of each electrode of the light-emitting element. See Figure 9(C).

[0346] The partition wall 145 has an opening that overlaps with the electrode. The conductive film exposed by the opening. This functions as the anode of the light-emitting element. In this embodiment, the partition wall 145 is made of polyimide resin. Use fat.

[0347] Furthermore, in steps 1 to 3, the EL layer (the layer containing organic compounds) is damaged. Because there is no risk, various film formation methods and microfabrication techniques can be applied. This involves forming a reflective conductive layer using a sputtering method, and then using a lithography method to... A pattern is formed on the electrode layer, and then a dry etching method or a wet etching method is used. Then, by processing the conductive layer into an island shape, the conductive layer 101a and electrode 10 constitute the electrode 101. A conductive layer 103a constituting 3 and a conductive layer 104a constituting electrode 104 are formed. Subsequently, a transparent conductive film is deposited using the sputtering method, and then lithography is used. Then, a pattern is formed on the transparent conductive film, and then a wet etching method is used. Then, the transparent conductive film is processed into an island shape to form electrodes 101, 103, and 10 Form 4.

[0348] ≪Step 4≫ The fourth step involves a hole injection layer 111, a hole transport layer 112, a light-emitting layer 180, and an electron transport layer. This is a step to form 113, an electron injection layer 114, and a charge generation layer 115 (Figure 10(A)). reference).

[0349] As the hole injection layer 111, a material containing a hole transporting material and an acceptor material is co-evaporated. It can be formed by deposition. Co-deposition is the process of depositing multiple different materials together. This is a vapor deposition method in which evaporation occurs simultaneously from an evaporation source. In addition, the hole transport layer 112 is a hole It can be formed by depositing a transportable material.

[0350] The luminescent layer 180 can be purple, blue, blue-green, green, yellow-green, yellow, orange, or red. By depositing at least one luminescent guest material selected from among them, the shape is formed. This can be achieved. As guest materials, luminescent organic compounds that exhibit fluorescence or phosphorescence can be used. It can be used. Also, the configuration of the light-emitting layer shown in Embodiments 1 to 3 can be used. It is preferable that it be present. Furthermore, the light-emitting layer 180 may have a two-layer configuration. In that case, Preferably, the two light-emitting layers each contain a light-emitting material that exhibits a different light emission color from the other. .

[0351] The electron transport layer 113 can be formed by depositing a material with high electron transport properties. It is possible. Furthermore, the electron injection layer 114 is formed by depositing a material with high electron injection properties. It is possible.

[0352] As the charge generation layer 115, electron acceptors are added to a hole transport material. Deposition of a material, or a material to which an electron donor has been added to an electron transport material. It can be formed with.

[0353] ≪Step 5≫ The fifth step involves a hole injection layer 116, a hole transport layer 117, a light-emitting layer 170, and an electron transport layer. This is a step in which 118, the electron injection layer 119, and the electrode 102 are formed (see Figure 10(B)). .

[0354] The hole injection layer 116 is made of the same material and is made using the same method as the hole injection layer 111 described above. It can be formed more easily. Also, as the hole transport layer 117, the hole transport layer 11 shown above It can be formed using the same materials and methods as in 2.

[0355] The light-emitting layer 170 can be purple, blue, blue-green, green, yellow-green, yellow, orange, or red. By depositing at least one luminescent guest material selected from among them, the shape is formed. This can be achieved. Fluorescent organic compounds can be used as guest materials. Furthermore, the fluorescent organic compound may be deposited alone, but it may also be deposited mixed with other materials. Alternatively, a fluorescent organic compound may be used as a guest material, and the excitation energy of the guest material may be The guest material may be dispersed and deposited onto a large host material.

[0356] The electron transport layer 118 is made of the same material and is constructed using the same method as the electron transport layer 113 described above. It can be formed more easily. Also, as the electron injection layer 119, the electron injection layer 11 shown above It can be formed using the same materials and methods as in 4.

[0357] The electrode 102 consists of a reflective conductive film and a translucent conductive film laminated together. It can be formed as follows. Also, the electrode 102 can be a single-layer structure or a multi-layer structure. That's good too.

[0358] After the above process, regions 222 are formed on electrodes 101, 103, and 104, respectively. A light-emitting element having region B, region 222G, and region 222R is formed on the substrate 200.

[0359] Step 6 The sixth step is to place a light-shielding layer 223, optical element 224B, and optical element 224 on the substrate 220. This is the process of forming G and the optical element 224R (see Figure 10(C)).

[0360] As the light-shielding layer 223, a resin film containing black pigment is formed in the desired area. After that, the base On the plate 220 and the light-shielding layer 223, optical element 224B, optical element 224G, and optical element 2 Forming 24R. As the optical element 224B, a resin film containing blue pigment is formed in the desired region. Formed. In addition, as the optical element 224G, a resin film containing green pigment is formed in a desired region. Furthermore, as the optical element 224R, a resin film containing red pigment is formed in the desired region. do.

[0361] ≪Step 7≫ The seventh step is to have a light-emitting element formed on substrate 200 and a light-emitting element formed on substrate 220 The light-shielding layer 223, optical element 224B, optical element 224G, and optical element 224R are attached. This is the process of sealing the parts together using a sealing material (not shown in the diagram).

[0362] Through the above steps, the light-emitting element 262a shown in Figure 8(A) can be formed.

[0363] The configuration shown in this embodiment may be used in appropriate combination with the configurations shown in other embodiments. It is possible to be there.

[0364] (Embodiment 5) In this embodiment, a display device according to one aspect of the present invention will be described using Figures 11 to 19. I will reveal it.

[0365] <Example of display device configuration 1> Figure 11(A) is a top view showing the display device 600, and Figure 11(B) is the same as Figure 11(A) but with a dashed line. This is a cross-sectional view taken along lines AB and the dashed line CD. The display device 600 includes a drive circuit section ( It has a signal line driving circuit section 601, a scan line driving circuit section 603, and a pixel section 602. Furthermore, the signal line drive circuit section 601, the scan line drive circuit section 603, and the pixel section 602 emit light. It has a function to control the light emission of the element.

[0366] Furthermore, the display device 600 includes an element substrate 610, a sealing substrate 604, and a sealing material 605. The area 607 surrounded by the sealing material 605, the routed wiring 608, and the FPC 609 are all included. do.

[0367] Furthermore, the routing wiring 608 is connected to the signal line drive circuit section 601 and the scan line drive circuit section 603. This is wiring for transmitting input signals, and it connects to the FPC609, which is an external input terminal, for video input. It receives signals such as the O signal, clock signal, start signal, and reset signal. Note that here it is FP Only C609 is shown in the diagram, but FPC609 is a printed circuit board (PWB: Pri A wired wiring board may be attached.

[0368] Furthermore, the signal line drive circuit section 601 consists of an N-channel type transistor 623 and a P-channel type A CMOS circuit is formed by combining it with transistor 624. The path section 601 or the scan line drive circuit section 603 includes various CMOS circuits, PMOS circuits, and An NMOS circuit can be used. In addition, in this embodiment, the drive circuit section is mounted on the substrate. The image shows a display device in which the formed driver and pixels are arranged on the same surface, but this is not necessarily required. Alternatively, the drive circuit can be formed externally instead of on the circuit board.

[0369] Furthermore, the pixel section 602 includes a switching transistor 611 and a current control transistor. The lower part electrically connected to the drain of transistor 612 for current control and transistor 612 It has an electrode 613. A partition wall 614 is formed to cover the end of the lower electrode 613. A positive-type photosensitive acrylic resin film can be used as the partition wall 614.

[0370] Furthermore, in order to improve coverage, the upper or lower end of the partition wall 614 has a curved surface with curvature. To ensure that a structure is formed. For example, positive-type photosensitive acrylic is used as the material for the partition wall 614. If so, the upper end of the partition wall 614 will have a curve with a radius of curvature (0.2 μm or more and 3 μm or less). It is preferable to give it a surface. Also, as the partition wall 614, a negative type photosensitive resin or a poly Any type of photosensitive resin can be used.

[0371] Furthermore, the structure of the transistors (transistors 611, 612, 623, 624) is particularly... It is not limited. For example, a staggered transistor may be used. Also, the transistor There are no particular limitations regarding polarity, and it includes N-channel and P-channel transistors. A structure that includes either an N-channel transistor or a P-channel transistor. A structure consisting of only one of the two may also be used. Furthermore, the semiconductor film crystal used in transistors... There are no particular limitations regarding properties. For example, amorphous semiconductor films and crystalline semiconductor films can be used. Yes, it is possible. Furthermore, semiconductor materials include Group 14 semiconductors (such as silicon) and compound semiconductors (oxides). Semiconductors (including organic semiconductors), etc., can be used. Examples of transistors include: Energy gap of 2 eV or more, preferably 2.5 eV or more, more preferably 3 eV By using the above oxide semiconductors, the off-current of the transistor can be reduced. Preferably, the oxide semiconductor is In-Ga oxide, In-M-Zn oxide (M is Aluminum (Al), gallium (Ga), yttrium (Y), zirconium (Zr ), lanthanum (La), cerium (Ce), tin (Sn), hafnium (Hf), or ne Examples include odymium (Nd).

[0372] An EL layer 616 and an upper electrode 617 are formed on the lower electrode 613, respectively. The lower electrode 613 functions as the anode, and the upper electrode 617 functions as the cathode. ru.

[0373] Furthermore, the EL layer 616 can be coated using a deposition method with a deposition mask, an inkjet method, or a spin coat. It is formed by various methods such as the law. In addition, the material that constitutes the EL layer 616 is low It may be a molecular compound or a polymeric compound (including oligomers and dendrimers).

[0374] Furthermore, the lower electrode 613, the EL layer 616, and the upper electrode 617 contribute to the light-emitting element 618. The light-emitting element 618 is formed. The light-emitting element 618 has the configuration of Embodiments 1 to 3. It is preferable that this is the case. Note that if multiple light-emitting elements are formed in the pixel portion, then Embodiments 1 to This includes both the light-emitting element described in Embodiment 3 and light-emitting elements having other configurations. You can.

[0375] Furthermore, by bonding the sealing substrate 604 to the element substrate 610 with the sealing material 605, A light-emitting element is placed in the region 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealing material 605. The structure is equipped with child 618. Furthermore, the area 607 is filled with filler material. In addition to cases where an inert gas (such as nitrogen or argon) is filled, it is also used in sealant 605. In some cases, it may be filled with UV-curing resin or thermosetting resin, for example, PVC ( Polyvinyl chloride resins, acrylic resins, polyimide resins, epoxy resins, Silicone resin, PVB (polyvinyl butyral) resin, or EVA (ethylene vinyl A resin (such as a luacetate) can be used. A recess is formed in the sealing substrate, and a desiccant is placed therein. Providing this feature can suppress deterioration due to moisture, making it a desirable configuration.

[0376] Furthermore, the optical element 621 is positioned below the sealing substrate 604 so as to overlap with the light-emitting element 618. It is provided therein. Furthermore, a light-shielding layer 622 is provided below the sealing substrate 604. Optical element 621 and the light-shielding layer 622 are the optical element and the light-shielding layer shown in Embodiment 3, respectively. A similar configuration would suffice.

[0377] Furthermore, it is preferable to use epoxy resin or glass frit for the sealant 605. Furthermore, it is desirable that these materials be as impermeable to moisture and oxygen as possible. In addition, as materials used for the sealing substrate 604, glass substrates and quartz substrates are also available, as well as FRP (Fiber Reinforced Plastic). Reinforced Plastics), PVF (Polyvinyl Fluoride), Poly A plastic substrate made of ester or acrylic can be used.

[0378] As described above, the light-emitting element and optical element described in Embodiments 1 to 3 are A display device can be obtained.

[0379] <Example of display device configuration 2> Next, another example of a display device will be explained using Figures 12(A)(B) and 13. Figures 12(A)(B) and 13 are cross-sectional views of a display device according to one embodiment of the present invention. .

[0380] Figure 12(A) shows the substrate 1001, the underlayer insulating film 1002, the gate insulating film 1003, and the gate Electrodes 1006, 1007, 1008, first interlayer insulating film 1020, second interlayer insulating film 10 21, peripheral portion 1042, pixel portion 1040, drive circuit portion 1041, lower electrode 10 of light-emitting element 24R, 1024G, 1024B, partition wall 1025, EL layer 1028, upper electrode of light-emitting element 1026, the sealing layer 1029, the sealing substrate 1031, the sealing material 1032, etc. are shown in the diagram. .

[0381] Furthermore, in Figure 12(A), as an example of an optical element, a colored layer (red colored layer 1034R) is shown. A green colored layer 1034G and a blue colored layer 1034B are provided on a transparent substrate 1033. A light-shielding layer 1035 may also be provided. A transparent material having a colored layer and a light-shielding layer. The substrate 1033 is aligned and fixed to the substrate 1001. Note that the colored layer and the light-shielding layer are also included. It is covered with an overcoat layer 1036. Also, in Figure 12(A), the colored layer Since light passing through it is red, green, and blue, an image can be represented using pixels of these three colors.

[0382] Figure 12(B) shows an example of an optical element, with a colored layer (red colored layer 1034R, green colored layer The colored layer 1034G and the blue colored layer 1034B are connected to the gate insulating film 1003 and the first interlayer insulating film. An example of formation between film 1020 and the substrate 1001 is shown. In this way, the colored layer is sealed with the substrate 1001. It may also be provided between the substrates 1031.

[0383] Figure 13 shows an example of an optical element, with a colored layer (red colored layer 1034R, green colored layer) 1034G, the blue colored layer 1034B) is connected to the first interlayer insulating film 1020 and the second interlayer insulating film This shows an example of formation between 1021 and substrate 1001. Thus, the colored layer is formed between substrate 1001 and the sealing group It may also be provided between the plates 1031.

[0384] Furthermore, in the display device described above, the side of the substrate 1001 on which the transistor is formed Although a display device with a light extraction structure (bottom emission type) was used, on the encapsulating substrate 1031 side It can also be used as a display device with a structure that extracts light (top emission type).

[0385] <Example of display device configuration 3> An example of a cross-sectional view of a top-emission type display device is shown in Figure 14(A)(B). Figure 14 Figures (A) and (B) are cross-sectional views illustrating a display device according to one embodiment of the present invention, and Figure 12(A) and (B) are cross-sectional views illustrating a display device according to one embodiment of the present invention. ) and the drive circuit section 1041, peripheral section 1042, etc. shown in Figure 13 are omitted for illustrative purposes.

[0386] In this case, the substrate 1001 can be a substrate that does not transmit light. Until the connecting electrode that connects to the anode of the optical element is fabricated, it will be a bottom-emission type display device. It is formed in the same manner as above. Then, the third interlayer insulating film 1037 is formed so as to cover the electrode 1022. This insulating film may also play a planarization role. The third interlayer insulating film 1037 is In addition to materials similar to those used for the interlayer insulating film in step 2, it can be formed using a variety of other materials.

[0387] The lower electrodes 1024R, 1024G, and 1024B of the light-emitting element are referred to as anodes here, but the negative electrodes are not. It can also be a pole. Also, a top-emission type display like Figure 14(A)(B) is also acceptable. If it is a device, the lower electrodes 1024R, 1024G, and 1024B have the function of reflecting light. It is preferable to do so. Also, an upper electrode 1026 is provided on the EL layer 1028. Electrode 1026 has the function of reflecting light and the function of transmitting light, and lower electrode 1024R, 10 A microcavity structure is employed between 24G, 1024B and the upper electrode 1026. It is preferable to increase the light intensity at a specific wavelength.

[0388] In the top emission structure shown in Figure 14(A), the colored layer (red colored layer 1034) Encapsulation substrate 1031 provided with R, a green colored layer 1034G, and a blue colored layer 1034B) Sealing can be performed using this method. The sealing substrate 1031 is positioned between pixels. A light layer 1035 may be provided. Furthermore, if a light-transmitting substrate is used for the sealing substrate 1031, It is suitable.

[0389] Furthermore, in Figure 14(A), multiple light-emitting elements are shown, and each of these multiple light-emitting elements is colored. While a configuration with layers has been given as an example, the system is not limited to this. For example, as shown in Figure 14(B) Without providing a green colored layer, a red colored layer 1034R and a blue colored layer 1034B are provided. Alternatively, a configuration that displays in full color using three colors—red, green, and blue—is also possible, as shown in Figure 14(A). Thus, when each light-emitting element is provided with a colored layer, external light reflection can be suppressed. This produces the desired effect. On the other hand, as shown in Figure 14(B), without providing a green coloring layer, red When a colored layer and a blue colored layer are provided, the light emitted from the green light-emitting element Because it has less energy loss, it has the effect of reducing power consumption.

[0390] <Example of display device configuration 4> The display device described above has a configuration having three subpixels (red, green, and blue), A structure having subpixels of four colors (red, green, blue, yellow, or red, green, blue, white) It may be considered as a component. Figures 15 to 17 show the lower electrodes 1024R, 1024G, 1024B, And the configuration of a display device having 1024Y. Figures 15(A)(B) and 16 show the tra A structure (bottom emission type) that extracts light from the substrate 1001 where the inverter is formed. This is a display device, and Figures 17(A) and 17(B) show a structure that extracts light from the encapsulated substrate 1031 side. It is a top-emission type display device.

[0391] Figure 15(A) shows the optical elements (colored layer 1034R, colored layer 1034G, colored layer 1034B This is an example of a display device in which a colored layer (1034Y) is provided on a transparent substrate (1033). Also, see Figure 15. (B) is an optical element (colored layer 1034R, colored layer 1034G, colored layer 1034B, colored layer An indication of forming 1034Y) between the gate insulating film 1003 and the first interlayer insulating film 1020. This is an example of the apparatus. Also, Figure 16 shows the optical elements (colored layer 1034R, colored layer 1034G, The color layer 1034B and the colored layer 1034Y are connected to the first interlayer insulating film 1020 and the second interlayer insulating film 1 This is an example of a display device formed between 021 and 021.

[0392] Colored layer 1034R transmits red light, colored layer 1034G transmits green light, colored layer 1034B has the function of transmitting blue light. In addition, the colored layer 1034Y transmits yellow light. A function that allows light to pass through, or a function that transmits multiple colors selected from blue, green, yellow, and red. The colored layer 1034Y transmits multiple lights selected from blue, green, yellow, and red. When it has the function of being yellow, the light transmitted through the colored layer 1034Y may be white. Because light-emitting elements that emit white light have high luminous efficiency, a display having a colored layer 1034Y The device can reduce power consumption.

[0393] Furthermore, in the top-emission type display device shown in Figure 17, the lower electrode 1024Y In the light-emitting element having the same lower electrode 1024R as in the display device in Figure 14(A), Between 1024G, 1024B, 1024Y and the upper electrode 1026, a microcavity A configuration having a structure is preferred. Also, in the display device shown in Figure 17(A), the colored layer (red colored layer Color layer 1034R, green colored layer 1034G, blue colored layer 1034B, and yellow colored layer Sealing can be performed using a sealing substrate 1031 provided with 1034Y).

[0394] The emission exhibited through the microcavity and the yellow colored layer 1034Y is in the yellow region. The emission will have an emission spectrum in the region. Since yellow is a color with high visual sensitivity, yellow emission will occur. A light-emitting element exhibiting this characteristic has high luminous efficiency. That is, a display device having the configuration shown in Figure 17(A) is This can reduce power consumption.

[0395] Furthermore, in Figure 17(A), multiple light-emitting elements are shown, and each of these light-emitting elements is colored. While a configuration with layers has been given as an example, the system is not limited to this. For example, as shown in Figure 17(B) Without providing a yellow colored layer, a red colored layer 1034R, a green colored layer 1034G, and a blue colored layer are provided. A colored layer 1034B is provided, and four colors are used: red, green, blue, and yellow, or red, green, blue, and white. A configuration that enables full-color display may also be used. As shown in Figure 17(A), a light-emitting element and the When a colored layer is provided on each optical element, it has the effect of suppressing external light reflection. It performs. On the other hand, as shown in Figure 17(B), the light-emitting element and the red without a yellow colored layer are used. If the configuration includes a colored layer, a green colored layer, and a blue colored layer, then yellow or white Because there is little energy loss from the light-emitting element, power consumption can be reduced. It produces the desired effect.

[0396] <Example of display device configuration 5> Next, another embodiment of the present invention is shown in Figure 18. Figure 18 is a reference to Figure 11(A This is a cross-sectional view taken along the dashed lines AB and CD of the ) in Figure 18. Therefore, parts having the same function as those shown in Figure 11(B) are denoted with the same reference numerals, and their details I will omit the detailed explanation.

[0397] The display device 600 shown in Figure 18 comprises an element substrate 610, a sealing substrate 604, and a sealing material 60 The region 607 enclosed by 5 has sealing layers 607a, 607b, and 607c. One or more of the sealing layers 607a, 607b, and 607c may include, for example, For example, PVC (polyvinyl chloride) resin, acrylic resin, polyimide resin, etc. Poxy resins, silicone resins, PVB (polyvinyl butyral) resins, or EVA Resins such as (ethylene vinyl acetate) resins can be used. Also, silica oxide silicon oxide nitride, silicon oxide nitride, silicon nitride, aluminum oxide, aluminum nitride Inorganic materials such as aluminum may also be used. Sealing layer 607a, sealing layer 607b, sealing layer 607 By forming c, the degradation of the light-emitting element 618 due to impurities such as water can be suppressed. Preferred. When forming sealing layer 607a, sealing layer 607b, and sealing layer 607c, It is not necessary to provide the 605 material.

[0398] Furthermore, sealing layers 607a, 607b, and 607c may be one or two of each. It may be the case that four or more sealing layers are formed. By making the sealing layers multilayered, water These impurities can penetrate from outside the display device 600 to the light-emitting element 618 inside the display device. This is preferable because it can effectively prevent this. Furthermore, if the sealing layer is multilayered, the resin and inorganic material A preferred configuration involves layering the materials.

[0399] <Example of display device configuration 6> Furthermore, the display devices shown in Configuration Examples 1 to 4 of this embodiment have optical elements. Although the above configuration has been illustrated, in one aspect of the present invention, optical elements may not be provided.

[0400] The display device shown in Figures 19(A) and (B) has a structure that extracts light from the encapsulated substrate 1031 side. This is a display device (up-emission type). Figure 19(A) shows the light-emitting layer 1028R and the light-emitting layer 1 This is an example of a display device having 028G and a light-emitting layer 1028B. Also, Figure 19(B) shows A table having a light layer 1028R, an emissive layer 1028G, an emissive layer 1028B, and an emissive layer 1028Y. This is an example of a display device.

[0401] The light-emitting layer 1028R emits red light, and the light-emitting layer 1028G emits green light. The light-emitting layer 1028B has the function of emitting blue light. The light-emitting layer 1028Y emits yellow light. A function that emits light, or a function that emits multiple lights selected from blue, green, and red. It has. The light emitted by the light-emitting layer 1028Y may be white. Yellow or white Because the light-emitting element has high luminous efficiency, a display device having the light-emitting layer 1028Y is It can reduce power consumption.

[0402] The display devices shown in Figures 19(A) and 19(B) include an EL layer that emits light of different colors. Since it is contained within the pixel, it is not necessary to provide a colored layer that acts as an optical element.

[0403] Furthermore, the sealing layer 1029 may be made of, for example, PVC (polyvinyl chloride) resin, acrylic Polyimide resins, epoxy resins, silicone resins, PVB (polyvinyl blue resin) Using resins such as ethylene vinyl acetate (EVA) resin or ethylene vinyl acetate resin. It is possible to do this. Also, silicon oxide, silicon oxide nitride, silicon oxide nitride, silicon nitride Inorganic materials such as aluminum oxide and aluminum nitride may also be used. The sealing layer 1029 Forming it this way is preferable because it can suppress the deterioration of the light-emitting element due to impurities such as water.

[0404] Furthermore, the sealing layer 1029 may consist of one or two of any four or more sealing layers. A layer may be formed. By making the sealing layer multilayered, impurities such as water can enter from outside the display device. This is preferable because it can effectively prevent penetration into the interior of the display device. In the case of a multilayer structure, a preferred configuration is one in which resin and inorganic material are laminated together.

[0405] Furthermore, the encapsulating substrate 1031 only needs to have a function to protect the light-emitting element. Therefore, a flexible substrate or film can be used for the sealing substrate 1031.

[0406] Note that the configuration shown in this embodiment may be appropriately combined with other embodiments or other configurations within this embodiment. They can be combined.

[0407] (Embodiment 6) In this embodiment, a display device having an light-emitting element according to one aspect of the present invention is shown in Figures 20 to We will explain using Figure 22.

[0408] Figure 20(A) is a block diagram illustrating a display device according to one embodiment of the present invention, and Figure 2 Figure 0(B) is a circuit diagram illustrating a pixel circuit in a display device according to one aspect of the present invention.

[0409] <Explanation regarding display devices> The display device shown in Figure 20(A) has a region having pixels of the display element (hereinafter referred to as the pixel portion 802 and ( ) and a circuit section ( ) which is located outside the pixel section 802 and has a circuit for driving the pixels. Hereinafter referred to as the drive circuit section 804, and a circuit having a function to protect the element (hereinafter referred to as the protection circuit 804) It has a (6) and a terminal section 807. Note that the protection circuit 806 is not provided. That's fine.

[0410] Part or all of the drive circuit section 804 is formed on the same substrate as the pixel section 802. This is desirable. This allows for a reduction in the number of components and terminals. Drive circuit section 804 If part or all of it is not formed on the same substrate as the pixel section 802, the drive cycle Part or all of road section 804 is COG or TAB (Tape Automated B It can be implemented by (onding).

[0411] The pixel section 802 is arranged in X rows (where X is a natural number greater than or equal to 2) and Y columns (where Y is a natural number greater than or equal to 2). It has a circuit for driving multiple display elements (hereinafter referred to as the pixel circuit 801), and the drive cycle The path section 804 is a circuit that outputs a signal (scan signal) for selecting pixels (hereinafter referred to as the scan line drive circuit). 804a) is used to supply signals (data signals) for driving the pixel display elements. It has a drive circuit such as the signal line drive circuit 804b.

[0412] The scan line driving circuit 804a includes a shift register and the like. A signal to drive the shift register is input via terminal 807, and the signal is output. For example, the scan line drive circuit 804a receives a start pulse signal, a clock signal, etc. The scan line drive circuit 804a outputs a pulse signal. The scanning signal is supplied to the wiring (and It has the function of controlling the potential of the scan lines (referred to as GL_1 to GL_X). Multiple drive circuits 804a are provided, and the scan line GL_1 is driven by multiple scan line drive circuits 804a. The path to GL_X may be divided and controlled. Alternatively, the scan line drive circuit 804a may use an initialization signal. It has the function of supplying, however, the scan line drive circuit 80 4a can also supply another signal.

[0413] The signal line drive circuit 804b includes a shift register, etc. The signal line drive circuit 804b is Through terminal 807, in addition to signals for driving the shift register, the data signals are generated. A signal (image signal) is input. The signal line drive circuit 804b uses the image signal to drive the pixel circuit It has the function of generating data signals to be written to 801. In addition, the signal line drive circuit 804b The data signal is transmitted according to the pulse signal obtained by inputting the start pulse, clock signal, etc. It has the function of controlling the output of the signal. In addition, the signal line drive circuit 804b is provided with a data signal. It has the function of controlling the potential of the wiring (hereinafter referred to as data lines DL_1 to DL_Y). Alternatively, the signal line drive circuit 804b may have the function of supplying an initialization signal. However, it is not limited to this, and the signal line drive circuit 804b may also supply other signals. It is possible.

[0414] The signal line drive circuit 804b is configured using, for example, multiple analog switches. The signal line drive circuit 804b sequentially turns on multiple analog switches, The image signal can be time-divided and output as a data signal. It can also use shift registers, etc. The signal line drive circuit 804b may be constructed using this.

[0415] Each of the multiple pixel circuits 801 receives a scan signal from one of the multiple scan lines GL. A pulse signal is input via one of several data lines DL to which a data signal is supplied. A data signal is input. In addition, each of the multiple pixel circuits 801 is a scan line drive circuit 804a controls the writing and retention of data in the data signal. For example, m rows and n columns. The pixel circuit 801 of the eye is driven by a scan line drive circuit via the scan line GL_m (where m is a natural number less than or equal to X). A pulse signal is input from 804a, and the data line DL_n( A data signal is input from the signal line drive circuit 804b via n (where n is a natural number less than or equal to Y).

[0416] The protection circuit 806 shown in Figure 20(A) is, for example, a scan line drive circuit 804a and a pixel circuit 8 It is connected to the scan line GL, which is the wiring between 01. Alternatively, the protection circuit 806 drives the signal line. It is connected to the data line DL, which is the wiring between circuit 804b and pixel circuit 801. Alternatively, The protection circuit 806 is connected to the wiring between the scan line drive circuit 804a and the terminal section 807. Yes, it is possible. Alternatively, the protection circuit 806 provides a connection between the signal line drive circuit 804b and the terminal section 807. It can be connected to a wire. The terminal 807 is used to supply power and to the display device from an external circuit. This refers to the part equipped with terminals for inputting control signals and image signals.

[0417] The protection circuit 806, when a potential outside a certain range is applied to the wiring to which it is connected, This is a circuit that creates a conductive state between two wires.

[0418] As shown in Figure 20(A), the pixel section 802 and the drive circuit section 804 each have a protection circuit 80 By providing 6, ESD (Electrostatic Discharge: This can improve the resistance of display devices to overcurrents generated by electrostatic discharge, etc. However, the configuration of the protection circuit 806 is not limited to this, for example, the scan line drive circuit 804a Configuration with protection circuit 806 connected, or with protection circuit 806 connected to signal line drive circuit 804b. This configuration is also possible. Alternatively, a configuration in which the protection circuit 806 is connected to the terminal 807. It can also be done this way.

[0419] Furthermore, in Figure 20(A), the scan line drive circuit 804a and the signal line drive circuit 804b are Therefore, although an example is shown in which the drive circuit section 804 is formed, the configuration is not limited to this. For example, only the scan line drive circuit 804a is formed, and a separately prepared signal line drive circuit is formed. A substrate (for example, a drive circuit substrate formed from a single-crystal semiconductor film or a polycrystalline semiconductor film) is mounted. This configuration is also good.

[0420] <Example of pixel circuit configuration> The multiple pixel circuits 801 shown in Figure 20(A) may be configured as shown in Figure 20(B), for example. It is possible.

[0421] The pixel circuit 801 shown in Figure 20(B) consists of transistors 852 and 854 and a capacitive element 86 It has 2 and a light-emitting element 872.

[0422] One of the source and drain electrodes of transistor 852 is supplied with a data signal. It is electrically connected to the wiring (data line DL_n). Furthermore, the gate of transistor 852 The electrodes are electrically connected to the wiring (scan line GL_m) to which the gate signal is applied.

[0423] Transistor 852 has the function of controlling the writing of data to the data signal.

[0424] One of the pair of electrodes of the capacitive element 862 is connected to a wiring to which a potential is supplied (hereinafter referred to as the potential supply line VL). It is electrically connected to (a), and the other is the source electrode and drain of transistor 852. It is electrically connected to the other electrode.

[0425] The capacitive element 862 functions as a holding capacitor to retain the written data.

[0426] One of the source and drain electrodes of transistor 854 is connected to the potential supply line VL_a. They are electrically connected. Furthermore, the gate electrode of transistor 854 is connected to the gate electrode of transistor 852. It is electrically connected to the other of the source electrode and drain electrode.

[0427] One of the light-emitting element 872's anode and cathode are electrically connected to the potential supply line VL_b. The other end is electrically connected to the source and drain electrodes of transistor 854. It will be done.

[0428] As the light-emitting element 872, the light-emitting elements shown in Embodiments 1 to 3 are used. It is possible.

[0429] Furthermore, a high power supply potential VDD is supplied to one of the potential supply lines VL_a and VL_b. On the other hand, a low power supply potential VSS is applied.

[0430] In a display device having the pixel circuit 801 shown in Figure 20(B), for example, the running shown in Figure 20(A) The line drive circuit 804a sequentially selects the pixel circuit 801 for each row, and the transistor 852 Turn it on and write the data signal.

[0431] When data is written to the pixel circuit 801, the transistor 852 turns off. It enters a holding state. Furthermore, in accordance with the potential of the written data signal, transistor 854 The amount of current flowing between the source electrode and the drain electrode is controlled, and the light-emitting element 872 controls the amount of current flowing through it. It emits light with brightness corresponding to the flow rate. By performing this sequentially for each row, an image can be displayed.

[0432] Furthermore, the pixel circuit has a function to compensate for the effects of fluctuations in the transistor threshold voltage, etc. This may be done. Figures 21(A)(B) and 22(A)(B) show examples of pixel circuits.

[0433] The pixel circuit shown in Figure 21(A) consists of six transistors (transistors 303_1 to 303_3). It has 03_6), a capacitive element 304, and a light-emitting element 305. Also, Figure 21(A) The pixel circuit shown includes wiring 301_1 to 301_5, as well as wiring 302_1 and wiring 30 2_2 is electrically connected. Regarding transistors 303_1 to 303_6... For example, a P-channel transistor can be used.

[0434] The pixel circuit shown in Figure 21(B) is the same as the pixel circuit shown in Figure 21(A), but with transistor 303 This configuration includes the addition of _7. Furthermore, the pixel circuit shown in Figure 21(B) includes wiring 301_6 and Wiring 301_7 is electrically connected. Here, wiring 301_5 and wiring 301_6 These may be electrically connected to each other. Regarding transistor 303_7... For example, a P-channel transistor can be used.

[0435] The pixel circuit shown in Figure 22(A) consists of six transistors (transistors 308_1 to 308_3). It has 08_6), a capacitive element 304, and a light-emitting element 305. Also, in Figure 22(A) The pixel circuit shown includes wiring 306_1 to 306_3, and wiring 307_1 to 307_ 3 is electrically connected. Here, wiring 306_1 and wiring 306_3 are electrically connected. They may be electrically connected. Regarding transistors 308_1 to 308_6: For example, a P-channel transistor can be used.

[0436] The pixel circuit shown in Figure 22(B) consists of two transistors (transistor 309_1 and Rangitator 309_2) and two capacitive elements (capacitive element 304_1 and capacitive element 304_ 2) and a light-emitting element 305 are included. Also, the pixel circuit shown in Figure 22(B) has wiring 3 Wirings 11_1 to 311_3, 312_1, and 312_2 are electrically connected. Furthermore, by using the pixel circuit configuration shown in Figure 22(B), for example, voltage input - power A flow-driven system (also called a CVCC system) can be used. Note that transistor 309_ For 1 and 309_2, for example, a P-channel transistor can be used. .

[0437] Furthermore, a light-emitting element according to one aspect of the present invention is an active element having an active element in the pixels of a display device. Trix system, or passive matrix system where the pixels of the display device do not have active elements. It can be applied to each method.

[0438] In the active matrix system, the active elements (active elements, nonlinear elements) are, In addition to transistors, various active elements (active elements, nonlinear elements) can be used. This can be done. For example, MIM (Metal Insulator Metal), or T It is also possible to use elements such as FD (Thin Film Diode). Because it involves fewer manufacturing steps, it is possible to reduce manufacturing costs or improve yield. Alternatively, these elements can improve the aperture ratio due to their small size. This allows for lower power consumption and higher brightness.

[0439] Other than the active matrix method, there are active elements (active elements, nonlinear elements) It is also possible to use a passive matrix type that does not use active elements. Because it does not use sub-elements or nonlinear elements, the manufacturing process is simpler, resulting in reduced manufacturing costs or higher yield. This can improve the performance. Alternatively, active elements (active elements, nonlinear elements) can be used. Because it does not exist, the aperture ratio can be improved, leading to lower power consumption or higher brightness. It is possible.

[0440] The configuration shown in this embodiment may be used in appropriate combination with the configurations shown in other embodiments. It is possible.

[0441] (Embodiment 7) In this embodiment, a display device having a light-emitting element according to one aspect of the present invention, and the display device An electronic device with an input device attached will be explained using Figures 23 to 27.

[0442] <Explanation regarding the touch panel 1> In this embodiment, as an example of electronic equipment, a display device and an input device are combined. This document describes the Touch Panel 2000. It also explains the Touch Sensor as an example of an input device. This section explains the case where the character "Sa" is present.

[0443] Figures 23(A) and 23(B) are perspective views of the Touch Panel 2000. In section B), for clarity, typical components of the touch panel 2000 are shown.

[0444] The touch panel 2000 has a display device 2501 and a touch sensor 2595 (Figure 2). See 3(B). Also, the touch panel 2000 is made up of substrate 2510, substrate 2570, and substrate It has a plate 2590. Note that substrates 2510, 2570, and 2590 are all It is flexible. However, any one of substrates 2510, 2570, and 2590 The configuration may be one or all of which lack flexibility.

[0445] The display device 2501 has multiple pixels on the substrate 2510 and supplies signals to these pixels. It has multiple wirings 2511. The multiple wirings 2511 are located on the outer periphery of the substrate 2510. It is routed through, and a portion of it forms terminal 2519. Terminal 2519 is FPC2509 (1) is electrically connected to the signal line drive circuit 2503s. The signal from (1) can be supplied to multiple pixels.

[0446] The circuit board 2590 has a touch sensor 2595 and is electrically connected to the touch sensor 2595. It has multiple wires 2598. The multiple wires 2598 are routed around the outer periphery of the substrate 2590. A portion of it forms a terminal. This terminal is electrically connected to FPC2509(2). The process continues. Note that in Figure 23(B), for clarity, the back side of substrate 2590 (substrate 2510) is shown. The electrodes and wiring of the touch sensor 2595, which is located on the opposite side, are shown with solid lines. .

[0447] For example, a capacitive touch sensor can be used as the touch sensor 2595. Capacitive capacitance methods include surface capacitance and projected capacitance.

[0448] Projected capacitance systems are classified into self-capacitance and mutual-capacitance types, mainly based on differences in their driving methods. There are several advantages. Using a mutual capacitance method is preferable because it enables simultaneous multi-point detection.

[0449] Note that the touch sensor 2595 shown in Figure 23(B) is a projected capacitive touch sensor. This configuration applies the "S" setting.

[0450] Furthermore, the touch sensor 2595 can detect the proximity or contact of an object to be detected, such as a finger. Yes, various sensors can be applied.

[0451] The projected capacitive touch sensor 2595 has electrodes 2591 and 2592. Electrode 2591 is electrically connected to one of the multiple wires 2598, and electrode 2592 is Connect electrically to any of the other wires 2598.

[0452] As shown in Figures 23(A) and 23(B), the electrode 2592 is arranged in multiple repeating directions. It has a shape in which the quadrilaterals are connected at their corners.

[0453] Electrode 2591 is quadrilateral and repeats in a direction intersecting the direction in which electrode 2592 extends. It is positioned.

[0454] Wiring 2594 is electrically connected to the two electrodes 2591 that sandwich electrode 2592. A shape that minimizes the area of ​​the intersection between electrode 2592 and wiring 2594 is preferable. This reduces the area where electrodes are not provided, thereby reducing variations in transmittance. Yes, it is possible. As a result, it reduces the variation in brightness of the light transmitted through the touch sensor 2595. It is possible.

[0455] Note that the shapes of electrodes 2591 and 2592 are not limited to these and can take on various shapes. For example, multiple electrodes 2591 are arranged so that there are as few gaps as possible, and an insulating layer is used. Multiple electrodes 2592 are provided spaced apart so that there is a region that does not overlap with electrode 2591. This configuration may also be used. In this case, between the two adjacent electrodes 2592, there is an electrical connection between them. Providing an insulated dummy electrode is preferable because it reduces the area of ​​regions with different transmittances. .

[0456] <Explanation regarding display devices> Next, the details of the display device 2501 will be explained using Figure 24(A). This corresponds to the cross-sectional view between the dashed line X1 and X2 shown in Figure 23(B).

[0457] The display device 2501 has a plurality of pixels arranged in a matrix. These pixels are display elements. It has a child and a pixel circuit that drives the display element.

[0458] The following explanation applies to the case where a light-emitting element that emits white light is applied to the display element. As explained above, the display elements are not limited to these. For example, the light emitted from each adjacent pixel You may use light-emitting elements with different emission colors to achieve a different color.

[0459] For example, substrates 2510 and 2570 have a water vapor transmission rate of 1 × 10⁻⁶ -5 g. m -2 ·day -1 The following is preferably 1 × 10 -6 g·m -2 ·day -1 The following is possible Flexible materials can be suitably used. Alternatively, the thermal expansion coefficient of the substrate 2510 and the base It is preferable to use a material whose thermal expansion coefficient is approximately equal to that of plate 2570. For example, linear expansion coefficient is 1 x 10 -3 / K or less, preferably 5 × 10 -5 / K or less, more comfortable 1×10 - 5 Materials with a temperature of 0.1 / K or lower can be suitably used.

[0460] The substrate 2510 includes an insulating layer 2510a that prevents the diffusion of impurities to the light-emitting element, and a flexible Adhesive layer 2 for bonding substrate 2510b, insulating layer 2510a, and flexible substrate 2510b It is a laminate having 510c. Furthermore, the substrate 2570 is a laminate that allows impurities to diffuse into the light-emitting element. An insulating layer 2570a to prevent leakage, a flexible substrate 2570b, and the insulating layer 2570a and the flexible substrate The laminate has an adhesive layer 2570c that bonds 2570b together.

[0461] Examples of adhesive layers 2510c and 2570c include polyester, polyolefin, etc. Polyamide (nylon, aramid, etc.), polyimide, polycarbonate, or acrylic Ryl, urethane, and epoxy can be used. In addition, resins having siloxane bonds can be used. The following materials can be used.

[0462] Furthermore, a sealing layer 2560 is provided between substrate 2510 and substrate 2570. (Sealing layer 2560) It is preferable that it has a refractive index greater than that of air. Also, as shown in Figure 24(A), sealing If light is to be extracted to the layer 2560 side, the sealing layer 2560 can also serve as an optical bonding layer. Cut.

[0463] Furthermore, a sealing material may be formed on the outer periphery of the sealing layer 2560. As a result, the region surrounded by substrate 2510, substrate 2570, sealing layer 2560, and sealing material The configuration can include a light-emitting element 2550R. The sealing layer 2560 is as follows: An inert gas (such as nitrogen or argon) may be used for filling. Furthermore, a desiccant may be placed inside the inert gas. A structure that adsorbs moisture, etc., may be provided. Alternatively, a resin such as acrylic or epoxy may be used. It may also be filled with oil. Furthermore, as the sealing material mentioned above, for example, epoxy resin or It is preferable to use glass frit. Also, as a material used for sealing, moisture and acid It is preferable to use a material that does not allow light to pass through.

[0464] Furthermore, the display device 2501 has pixels 2502R. Also, pixels 2502R are light-emitting pixels. It has a joule of 2580R.

[0465] Pixel 2502R is connected to the light-emitting element 2550R and supplies power to the light-emitting element 2550R. It has a transistor 2502t that can do this. Note that transistor 2502t is a pixel It functions as part of the circuit. Also, the light-emitting module 2580R and the light-emitting element 2550R, It has a colored layer 2567R.

[0466] The light-emitting element 2550R has a lower electrode, an upper electrode, and an EL layer between the lower electrode and the upper electrode. It has the following characteristics. As the light-emitting element 2550R, for example, the light-emitting elements shown in Embodiments 1 to 3 Optical elements can be applied.

[0467] Furthermore, a microcavity structure is employed between the lower electrode and the upper electrode, allowing for specific wavelengths. The light intensity may be increased.

[0468] Furthermore, if the sealing layer 2560 is provided on the side from which light is extracted, the sealing layer 2560 is It is in contact with the optical element 2550R and the colored layer 2567R.

[0469] The colored layer 2567R is located in a position that overlaps with the light-emitting element 2550R. A portion 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. It is emitted to the outside of the 2580R optical module.

[0470] Furthermore, the display device 2501 is provided with a light-shielding layer 2567BM in the direction from which light is emitted. The light-shielding layer 2567BM is provided so as to surround the colored layer 2567R.

[0471] The colored layer 2567R only needs to have the function of transmitting light in a specific wavelength range. For example, a color filter that transmits light in the red wavelength range, and a color filter that transmits light in the green wavelength range. Color filters, color filters that transmit light in the blue wavelength range, color filters that transmit light in the yellow wavelength range Transparent color filters can be used. Each color filter is made from various materials. Using printing methods, inkjet methods, and etching methods using photolithography technology, It can be formed in any way.

[0472] Furthermore, the display device 2501 is provided with an insulating layer 2521. The insulating layer 2521 is made of transistors. It covers the ZISTA 2502t. The insulating layer 2521 flattens the irregularities caused by the pixel circuit. It has the function to do so. In addition, the insulating layer 2521 is given the function to suppress the diffusion of impurities. This may be done. This will prevent a decrease in the reliability of transistors such as the 2502t due to the diffusion of impurities. It can be suppressed.

[0473] Furthermore, the light-emitting element 2550R is formed above the insulating layer 2521. The lower electrode of the 550R is provided with a partition wall 2528 that overlaps the end of the lower electrode. Furthermore, a spacer that controls the distance between substrate 2510 and substrate 2570 is placed on the partition wall 2528. It may be formed.

[0474] The scan line driving circuit 2503g(1) consists of a transistor 2503t and a capacitive element 2503c It has the following characteristics. Furthermore, the drive circuit can be formed on the same substrate using the same process as the pixel circuit. ru.

[0475] Furthermore, wiring 2511 that can supply signals is provided on the circuit board 2510. Furthermore, terminal 2519 is provided on wiring 2511. Also, terminal 2519 has FP C2509(1) is electrically connected. Also, FPC2509(1) receives the video signal. It has the function of supplying clock signals, start signals, reset signals, etc. Note: FPC2 A printed circuit board (PWB) may be attached to 509(1).

[0476] Furthermore, transistors of various structures can be applied to the display device 2501. (Figure) In 24(A), an example is given of the case where a bottom-gate type transistor is applied. However, it is not limited to this, and for example, as shown in Figure 24(B), a top-gate type transient The system may also be configured to apply the st to the display device 2501.

[0477] Furthermore, regarding the polarity of transistors 2502t and 2503t, there are no particular limitations. There is no fixed definition, and the structure has N-channel and P-channel transistors, N-channel type A structure consisting of either a transistor or a P-channel transistor is used. It may be there. Also, the semiconductor film crystal used in transistors 2502t and 2503t There are no particular limitations regarding properties. For example, amorphous semiconductor films and crystalline semiconductor films can be used. Yes, it is possible. Also, as a semiconductor material, Group 14 semiconductors (for example, semiconductors containing silicon) are used. Compound semiconductors (including oxide semiconductors), organic semiconductors, etc. can be used. Either or both of transistors 2502t and 2503t have energy gear Oxides with a cap of 2 eV or more, preferably 2.5 eV or more, and more preferably 3 eV or more. Using semiconductors is preferable because it reduces the transistor's off-current. Examples of such oxide semiconductors include In-Ga oxide and In-M-Zn oxide (where M is Al, G). Examples include (representing a, Y, Zr, La, Ce, Sn, Hf, or Nd).

[0478] <Explanation regarding touch sensors> Next, we will explain the details of the touch sensor 2595 using Figure 24(C). Figure 24 (C) corresponds to the cross-sectional view between the dashed line X3 and X4 shown in Figure 23(B).

[0479] The touch sensor 2595 has electrodes 2591 and electrodes arranged in a staggered pattern on the substrate 2590. 2592, an insulating layer 2593 covering electrodes 2591 and 2592, and adjacent electrodes 25 It has wiring 2594 that electrically connects 91.

[0480] Electrodes 2591 and 2592 are formed using a light-transmitting conductive material. Conductive materials having this property include indium oxide, indium tin oxide, and indium zinc oxide. Conductive oxides such as zinc oxide, zinc oxide, and zinc oxide with added gallium can be used. Furthermore, a film containing graphene can also be used. A film containing graphene is, for example, a film-like structure. A film containing graphene oxide formed on the surface can be reduced to form a new film. Methods such as applying heat can be cited.

[0481] For example, a light-transmitting conductive material is deposited on a substrate 2590 by sputtering. Afterward, unwanted parts are removed using various pattern formation techniques such as photolithography. Electrodes 2591 and 2592 can be formed.

[0482] Furthermore, the materials used for the insulating layer 2593 include, for example, resins such as acrylic and epoxy. In addition to resins containing siloxane bonds, silicon oxide, silicon oxide nitride, aluminum oxide Inorganic insulating materials such as MU can also be used.

[0483] Furthermore, an opening reaching the electrode 2591 is provided in the insulating layer 2593, and the wiring 2594 is adjacent to it. It is electrically connected to electrode 2591. The light-transmitting conductive material increases the aperture ratio of the touch panel. Because it can be done this way, it can be suitably used in wiring 2594. Also, electrode 2591 Furthermore, materials with higher conductivity than electrode 2592 are preferable for wiring 2594 because they can reduce electrical resistance. It can be used appropriately.

[0484] The electrode 2592 extends in one direction, and multiple electrodes 2592 are arranged in a stripe pattern. Furthermore, the wiring 2594 is provided intersecting with the electrode 2592.

[0485] A pair of electrodes 2591 are provided flanking one electrode 2592. Also, the wiring 2594 is A pair of electrodes 2591 are electrically connected.

[0486] Note that the multiple electrodes 2591 are not necessarily arranged in a direction perpendicular to that of a single electrode 2592. It is not necessary to do so; they may be arranged to form an angle greater than 0 degrees but less than 90 degrees.

[0487] Furthermore, wiring 2598 is electrically connected to electrode 2591 or electrode 2592. A portion of the wiring 2598 functions as a terminal. Wiring 2598 can be, for example, made of aluminum. Nium, gold, platinum, silver, nickel, titanium, tungsten, chromium, molybdenum, iron, corn Using metallic materials such as balsamic, copper, or palladium, or alloy materials containing such metallic materials. It is possible.

[0488] Furthermore, an insulating layer is provided to cover the insulating layer 2593 and the wiring 2594, and the touch sensor 2595 It may be protected.

[0489] Furthermore, the connecting layer 2599 electrically connects the wiring 2598 and the FPC2509(2). .

[0490] The connecting layer 2599 is an anisotropic conductive film (ACF: Anisotropic C (conductive film) or anisotropic conductive paste (ACP: Anisotropic) You can use tools such as IC Conductive Paste.

[0491] <Explanation regarding the touch panel 2> Next, we will explain the details of the touch panel 2000 using Figure 25(A). Figure 25 (A) corresponds to the cross-sectional view between the dashed line X5 and X6 shown in Figure 23(A).

[0492] The touch panel 2000 shown in Figure 25(A) is the same as the display device 250 described in Figure 24(A). This configuration consists of 1 and the touch sensor 2595 described in Figure 24(C) bonded together.

[0493] Furthermore, the touch panel 2000 shown in Figure 25(A) is shown in Figures 24(A) and 24(C). In addition to the configuration described, it also includes an adhesive layer 2597 and an anti-reflective layer 2567p.

[0494] 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. They are joined together. Furthermore, it is preferable that the adhesive layer 2597 has light-transmitting properties. Also, adhesive layer 2 For 597, a thermosetting resin or an ultraviolet curing resin can be used. For example, Using acrylic resin, urethane resin, epoxy resin, or siloxane resin It is possible.

[0495] The anti-reflective layer 2567p is provided in a position that overlaps with the pixel. For example, a circular polarizer can be used.

[0496] Next, for a touch panel with a configuration different from that shown in Figure 25(A), see Figure 25(B). I will use it to explain.

[0497] Figure 25(B) is a cross-sectional view of the touch panel 2001. The touch panel shown in Figure 25(B) Nell 2001 is a touch panel 2000 and a display device 2501 as shown in Figure 25(A). The position of the touch sensor 2595 is different. Here, we will explain the different configurations in detail. Where applicable, refer to the description of Touch Panel 2000 for details on how to use the provided configuration.

[0498] The colored layer 2567R is located in a position that overlaps with the light-emitting element 2550R. Also, in Figure 25(B) The light-emitting element 2550R shown emits light on the side where the transistor 2502t is located. As a result, some of the light emitted by the light-emitting element 2550R passes through the colored layer 2567R, The light is emitted to the outside of the light-emitting module 2580R in the direction of the arrow shown in the diagram.

[0499] Furthermore, the touch sensor 2595 is located on the circuit board 2510 side of the display device 2501. .

[0500] The adhesive layer 2597 is located between substrate 2510 and substrate 2590 and touches the display device 2501. Attach the Chisensa 2595.

[0501] As shown in Figures 25(A) and (B), the light emitted from the light-emitting element is directed towards the substrate 2510 and the base It is sufficient if the material is injected through either one or both of the plates 2570.

[0502] <Explanation of how the touch panel is operated> Next, an example of a touch panel driving method will be explained using Figures 26(A) and 26(B). cormorant.

[0503] Figure 26(A) is a block diagram showing the configuration of a mutually capacitive touch sensor. (A) shows the pulse voltage output circuit 2601 and the current detection circuit 2602. In Figure 26(A), the electrodes 2621 to which the pulse voltage is applied are designated as X1-X6, and the current changes... The electrodes 2622 that detect the change are shown as Y1-Y6, each represented by six wires. Furthermore, Figure 26(A) shows the capacitance 2 formed when electrode 2621 and electrode 2622 overlap. This indicates 603. Note that electrodes 2621 and 2622 have interchangeable functions. That's fine.

[0504] The pulse voltage output circuit 2601 is a circuit for sequentially applying pulses to the X1-X6 wiring. Therefore, when a pulse voltage is applied to the wiring X1-X6, the capacitance 2603 is formed. An electric field is generated between pole 2621 and electrode 2622. This electric field generated between electrodes is affected by shielding, etc. By causing a change in the mutual capacitance of the 2603 capacitance, the proximity of the detected object, or It can detect contact.

[0505] The current detection circuit 2602 detects changes in the mutual capacitance of capacitor 2603, and the wiring of Y1-Y6 This is a circuit for detecting changes in current. In the wiring of Y1-Y6, proximity of the object to be detected, Alternatively, if there is no contact, the detected current value will not change, but if the object being detected is nearby, When the mutual capacitance decreases due to contact, a change in the current value is detected. Output can be performed using an integrating circuit or similar.

[0506] Next, Figure 26(B) shows the input of the mutual capacitive touch sensor shown in Figure 26(A). The timing chart of the output waveform is shown. Figure 26(B) shows the timing of each matrix in one frame period. The system detects the object to be detected. Figure 26(B) shows the case where no object is detected (non-touch). This shows two cases: when detecting an object to be detected (touch). See Figure 26. (B) shows the waveform of the voltage value corresponding to the current value detected in the Y1-Y6 wiring. .

[0507] A pulse voltage is applied sequentially to the wiring of X1-X6, and Y1- The waveform changes in the Y6 wiring. If there is no proximity or contact with the detected object, X1-X6 The waveforms of Y1-Y6 change uniformly in response to changes in the voltage of the wiring. Meanwhile, when the object to be detected is nearby... Alternatively, at the point of contact, the current value decreases, and therefore the waveform of the corresponding voltage value also changes. ru.

[0508] In this way, by detecting changes in mutual capacitance, the proximity or contact of the object being detected can be detected. It is possible.

[0509] <Explanation regarding the sensor circuit> Furthermore, in Figure 26(A), only capacitor 2603 is provided at the wiring intersection as a touch sensor. The configuration of a passive matrix type touch sensor is shown, but it has transistors and capacitors. It may also be an active-matrix type touch sensor. An example of a sensor circuit included in the sensor is shown in Figure 27.

[0510] The sensor circuit shown in Figure 27 consists of capacitor 2603, transis...

Claims

[Claim 1] A light-emitting element having a host material and a guest material, The host material comprises a first organic compound and a second organic compound. The aforementioned guest material has the function of converting triplet excitation energy into light emission, The first organic compound has a difference between the singlet excitation energy level and the triplet excitation energy level that is greater than 0 eV and less than or equal to 0.2 eV. The first organic compound and the second organic compound form an excited complex. Light-emitting element.

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