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

Abstract

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

Description

[Technical Field]

[0001] One embodiment of the present invention is a light-emitting element, or a display device, an electronic device, and a lighting device each having the light-emitting element. Regarding the lighting device.

[0002] Note that one embodiment of the present invention is not limited to the above technical fields. The technical field of one aspect of the present invention relates to an article, a method, or a manufacturing method. is a process, machine, manufacture, or composition of matter. Therefore, the technical field of one embodiment of the present invention disclosed in this specification more specifically relates to Examples of the semiconductor device include a semiconductor device, a display device, a liquid crystal display device, a light-emitting device, a lighting device, a power storage device, a memory device, and the like. Examples include devices, methods for driving them, and methods for manufacturing them. . [Background technology]

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

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

[0005] A light-emitting element in which an organic material is used as the light-emitting material and an EL layer containing the light-emitting material is provided between a pair of electrodes. In the case of a device (for example, an organic EL device), applying a voltage between a pair of electrodes causes light to flow from the cathode Electrons are injected from the cathode and holes are injected from the anode into the luminescent EL layer, causing a current to flow. The injected electrons and holes are then recombined to excite the light-emitting organic material. The excited light-emitting organic material is then in a luminescent state, and light can be emitted from the excited light-emitting organic material.

[0006] The types of excited states that organic materials can form include singlet excited states (S * ) and triplet excited states state(T * ) emission from the singlet excited state is fluorescence, and emission from the triplet excited state is phosphorescence. The statistical generation ratio of these in a light-emitting element is called S * :T * =1 :3. Therefore, it is more effective to use a light-emitting element that emits phosphorescence than a light-emitting element that uses a material that emits fluorescence (fluorescent material). Therefore, a light-emitting element using a material that emits light (phosphorescent material) can have higher luminous efficiency. Therefore, phosphorescent materials capable of converting triplet excited state energy into luminescence are used. In recent years, development of light-emitting devices has been actively pursued (see, for example, Patent Document 1).

[0007] The energy required to excite an organic material depends on the LUMO and HOMO levels of the organic material. The energy difference depends on the energy difference between the excited state and the singlet state. In a light-emitting element using an organic material that emits phosphorescence, the triplet excitation energy is Therefore, the singlet excited state and triplet excited state formed by organic materials are converted into light-emitting energy. When the energy difference between the excited state and the non-excited state is large, the energy required to excite the organic material is The energy of the emitted light is higher by the amount of energy corresponding to the energy difference. The difference between the energy required to excite a material and the energy of light emission is This increases the driving voltage, which affects the element characteristics. Development is currently underway regarding this (see Patent Document 2).

[0008] Furthermore, among light-emitting elements using phosphorescent materials, light-emitting elements that emit blue light are However, it is difficult to develop stable compounds with high triplet excitation energy levels, so this has not yet been achieved. Therefore, there is a need to develop stable phosphorescent materials with high luminous efficiency. There is also a need to develop highly reliable phosphorescent light-emitting devices that exhibit high luminous efficiency. are. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-182699 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-212879 Summary of the Invention [Problem to be solved by the invention]

[0010] Iridium complexes are known as phosphorescent materials that exhibit high luminous efficiency. Energetic iridium complexes with pyridine skeletons or nitrogen-containing five-membered heterocyclic skeletons have been reported. Iridium complexes having a pyridine skeleton or a nitrogen-containing five-membered heterocycle as a ligand are known. The skeleton has high triplet excitation energy but low electron accepting property, so the skeleton is The iridium complexes have high HOMO and LUMO levels, and hole carriers are attracted to them. Therefore, a skeleton with higher electron-accepting properties is required. Development of iridium complexes containing iridium as ligands is currently underway.

[0011] On the other hand, iridium complexes with ligands having highly electron-accepting skeletons have high HOMO levels and The LUMO level is low, so electron carriers are easily injected, but hole carriers are difficult to inject. Therefore, in cases where excitation by direct recombination of carriers is difficult or where it is necessary to make the light-emitting element emit light efficiently, It may be difficult to

[0012] Therefore, in one embodiment of the present invention, a light-emitting element including a phosphorescent material has high emission efficiency. Another object of one embodiment of the present invention is to provide a light-emitting element having low power consumption. Another object of the present invention is to provide a light-emitting element with reduced signal loss. Another object of the present invention is to provide a light-emitting element with excellent reliability. Another object of the present invention is to provide a novel light-emitting element. Another object of the present invention is to provide a light-emitting device. One of the objectives is to provide a facility for

[0013] Note that the above description of the object does not preclude the existence of other objects. It is not necessary to solve all of these problems. Problems other than those mentioned above can be solved by the description of the specification, etc. It is obvious from the description of the specification, etc. that other problems can be extracted. do. [Means for solving the problem]

[0014] One embodiment of the present invention is a light-emitting element having an exciplex that can efficiently excite a phosphorescent material. He is a child.

[0015] Therefore, one aspect of the present invention is a method for producing a compound comprising: a first organic compound, a second organic compound, and a guest material; and a light-emitting device having a first organic compound and a second organic compound, The HOMO level of the first organic compound is lower than the LUMO level of the second organic compound. The LUMO level of the guest material is lower than the LUMO level of the first organic compound. The energy difference between the LUMO level and the HOMO level of the guest material is lower than that of the first organic compound. the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound is greater than the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound, The guest material has a function of converting triplet excitation energy into luminescence, and the first The light-emitting element is a combination of an organic compound and a second organic compound that form an exciplex. .

[0016] Another aspect of the present invention is a method for producing a photocatalytic reaction system comprising: a first organic compound, a second organic compound, and a guest material; and a LUMO level of the first organic compound is higher than that of the second organic compound. The HOMO level of the first organic compound is lower than the LUMO level of the second organic compound. The LUMO level of the guest material is lower than the LUMO level of the first organic compound. The energy difference between the LUMO level and the HOMO level of the guest material is low, and the energy difference between the LUMO level and the HOMO level of the first organic compound is low. the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound is greater than the energy difference between the first organic compound and the HOMO level of the second organic compound. The first active material has a function of converting triplet excitation energy into luminescence. a guest material, The energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound is The transition energy is equal to or greater than the transition energy calculated from the absorption edge in the absorption spectrum of the light emitting element.

[0017] Another aspect of the present invention is a method for producing a photocatalytic reaction system comprising: a first organic compound, a second organic compound, and a guest material; and a LUMO level of the first organic compound is higher than that of the second organic compound. The HOMO level of the first organic compound is lower than the LUMO level of the second organic compound. The LUMO level of the guest material is lower than the LUMO level of the first organic compound. The energy difference between the LUMO level and the HOMO level of the guest material is low, and the energy difference between the LUMO level and the HOMO level of the first organic compound is low. the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound is greater than the energy difference between the first organic compound and the HOMO level of the second organic compound. The first active material has a function of converting triplet excitation energy into luminescence. a guest material, The energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound is It is a light-emitting element that exhibits light emission energy equal to or greater than that of the light-emitting element.

[0018] In each of the above structures, the energy between the LUMO level and the HOMO level of the guest material is The difference is calculated from the transition energy calculated from the absorption edge in the absorption spectrum of the guest material. It is preferable that it is 0.4 eV or more larger.

[0019] In each of the above structures, the energy between the LUMO level and the HOMO level of the guest material is The difference is preferably 0.4 eV or more larger than the luminescence energy exhibited by the guest material.

[0020] In each of the above structures, the exciplex has a function of donating excitation energy to the guest material. In addition, the emission spectrum of the exciplex is preferably the same as the absorption spectrum of the guest material. It is preferable that the absorption band of the fluorine-containing compound has a region overlapping with the absorption band on the longest wavelength side of the spectrum.

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

[0022] In each of the above structures, the first organic compound has a function of transporting electrons. It is preferable that the second organic compound has a function of transporting holes. The first organic compound has a π-electron-deficient heteroaromatic ring skeleton, and the second organic compound has a π-electron-deficient heteroaromatic ring skeleton. It is preferable that the compound has at least one of an electron-excess heteroaromatic ring skeleton and an aromatic amine skeleton.

[0023] Another embodiment of the present invention is a light-emitting element having any of the above structures, a color filter, a seal, or a light-emitting device. Another embodiment of the present invention is a display device including the display device. The present invention also provides an electronic device having a touch sensor and a housing. The present invention is a lighting device having a light-emitting element having any of the above configurations and a housing or a touch sensor. Furthermore, one embodiment of the present invention is not only a light-emitting device having a light-emitting element, but also an electronic device having a light-emitting device. Therefore, the light-emitting device in this specification includes image display devices, It also refers to a light source (including lighting equipment). exible Printed Circuit), TCP (Tape Carrier) The TCP is attached to a module with a printed wiring board. The module is mounted with a COG (Chip On Glass) method. A module in which an integrated circuit (C) is directly mounted may also include a light-emitting device. [Effects of the Invention]

[0024] According to one embodiment of the present invention, a light-emitting element including a phosphorescent material has high emission efficiency. According to one embodiment of the present invention, a light-emitting element with reduced power consumption can be provided. According to one embodiment of the present invention, a highly reliable light-emitting element can be provided. Alternatively, according to one embodiment of the present invention, a novel light-emitting element can be provided. According to one embodiment of the present invention, a novel light-emitting device can be provided. Furthermore, according to one embodiment of the present invention, a novel display device can be provided.

[0025] The description of these effects does not preclude the existence of other effects. It is not necessary to have all of these effects. Effects other than these may be included in the description. It is obvious from the description of the specification, drawings, claims, etc. From this, it is possible to extract other effects. [Brief explanation of the drawings]

[0026] [Figure 1] 1A and 1B are schematic cross-sectional views of a light-emitting element according to one embodiment of the present invention. [Figure 2] 1A and 1B are diagrams illustrating the correlation between energy bands and the correlation between energy levels in a light-emitting layer of a light-emitting element according to one embodiment of the present invention. [Figure 3] 1A and 1B are schematic cross-sectional views of a light-emitting element of one embodiment of the present invention and a diagram illustrating the correlation between energy levels; [Figure 4] 1A and 1B are schematic cross-sectional views of a light-emitting element of one embodiment of the present invention and a diagram illustrating the correlation between energy levels; [Figure 5] 1A and 1B are schematic cross-sectional views of a light-emitting element according to one embodiment of the present invention. [Figure 6] 1A and 1B are schematic cross-sectional views of a light-emitting element according to one embodiment of the present invention. [Figure 7] 1A to 1C are schematic cross-sectional views illustrating a method for manufacturing a light-emitting element according to one embodiment of the present invention. [Figure 8] 1A to 1C are schematic cross-sectional views illustrating a method for manufacturing a light-emitting element according to one embodiment of the present invention. [Figure 9] 1A and 1B are a top view and a cross-sectional view schematic diagram illustrating a display device of one embodiment of the present invention. [Figure 10] 1A and 1B are schematic cross-sectional views illustrating a display device according to one embodiment of the present invention. [Figure 11] 1A and 1B are schematic cross-sectional views illustrating a display device according to one embodiment of the present invention. [Figure 12] 1A and 1B are schematic cross-sectional views illustrating a display device according to one embodiment of the present invention. [Figure 13] 1A and 1B are schematic cross-sectional views illustrating a display device according to one embodiment of the present invention. [Figure 14] 1A and 1B are schematic cross-sectional views illustrating a display device according to one embodiment of the present invention. [Figure 15] 1A and 1B are schematic cross-sectional views illustrating a display device according to one embodiment of the present invention. [Figure 16] 1A and 1B are schematic cross-sectional views illustrating a display device according to one embodiment of the present invention. [Figure 17] 1A and 1B are schematic cross-sectional views illustrating a display device according to one embodiment of the present invention. [Figure 18] 1A and 1B are a block diagram and a circuit diagram illustrating a display device of one embodiment of the present invention. [Figure 19] FIG. 1 is a circuit diagram illustrating a pixel circuit of a display device according to one embodiment of the present invention. [Figure 20] FIG. 1 is a circuit diagram illustrating a pixel circuit of a display device according to one embodiment of the present invention. [Figure 21] FIG. 1 is a perspective view illustrating an example of a touch panel of one embodiment of the present invention. [Figure 22] 1A and 1B are cross-sectional views illustrating examples of a display device and a touch sensor according to one embodiment of the present invention. [Figure 23] FIG. 1 is a cross-sectional view illustrating an example of a touch panel of one embodiment of the present invention. [Figure 24] 1A and 1B are a block diagram and a timing chart of a touch sensor according to one embodiment of the present invention. [Figure 25] FIG. 1 is a circuit diagram of a touch sensor according to one embodiment of the present invention. [Figure 26] FIG. 1 is a perspective view illustrating a display module of one embodiment of the present invention. [Figure 27]1A to 1C illustrate electronic devices of one embodiment of the present invention. [Figure 28] 1A to 1C illustrate electronic devices of one embodiment of the present invention. [Figure 29] FIG. 1 is a perspective view illustrating a display device according to one embodiment of the present invention. [Figure 30] 1A and 1B are a perspective view and a cross-sectional view illustrating a light-emitting device according to one embodiment of the present invention [Figure 31] FIG. 1 is a cross-sectional view illustrating a light-emitting device according to one embodiment of the present invention. [Figure 32] 1A to 1C illustrate a lighting device and an electronic device according to one embodiment of the present invention. [Figure 33] 1A to 1C illustrate a lighting device according to one embodiment of the present invention. [Figure 34] 1A and 1B are cross-sectional views illustrating a light-emitting element according to an embodiment. [Figure 35] FIG. 1 is a diagram illustrating an emission spectrum of a host material according to an example. [Figure 36] 4A and 4B are diagrams illustrating absorption spectra and emission spectra of guest materials according to an example. [Figure 37] FIG. 2 is a diagram illustrating phosphorescent emission spectra of host materials according to an example. [Figure 38] FIG. 10 is a graph showing luminance-current density characteristics of a light-emitting element according to an example. [Figure 39] FIG. 10 is a graph showing luminance-voltage characteristics of a light-emitting element according to an example. [Figure 40] FIG. 10 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 41] FIG. 10 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 42] 10A and 10B are graphs illustrating electroluminescence spectra of light-emitting elements according to Examples. [Figure 43] 10A to 10C are diagrams illustrating the results of a reliability test on a light-emitting element according to an example. [Figure 44] FIG. 4 is a diagram illustrating the correlation of energy bands according to an embodiment. [Figure 45] 10A and 10B are diagrams illustrating the light emission angle distribution of a light emitting element according to an example. [Figure 46]FIG. 10 is a graph showing luminance-current density characteristics of a light-emitting element according to an example. [Figure 47] FIG. 10 is a graph showing luminance-voltage characteristics of a light-emitting element according to an example. [Figure 48] FIG. 10 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 49] FIG. 10 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 50] 10A and 10B are graphs illustrating electroluminescence spectra of light-emitting elements according to Examples. [Figure 51] 4A and 4B are diagrams illustrating absorption spectra and emission spectra of guest materials according to an example. [Figure 52] 4A and 4B are diagrams illustrating absorption spectra and emission spectra of guest materials according to an example. [Figure 53] 10A to 10C are diagrams illustrating the results of a reliability test on a light-emitting element according to an example. [Figure 54] FIG. 10 is a graph showing luminance-current density characteristics of a light-emitting element according to an example. [Figure 55] FIG. 10 is a graph showing luminance-voltage characteristics of a light-emitting element according to an example. [Figure 56] FIG. 10 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 57] FIG. 10 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 58] 10A and 10B are graphs illustrating electroluminescence spectra of light-emitting elements according to Examples. [Figure 59] 10A to 10C are diagrams illustrating the results of a reliability test on a light-emitting element according to an example. [Figure 60] FIG. 10 is a graph showing luminance-current density characteristics of a light-emitting element according to an example. [Figure 61] FIG. 10 is a graph showing luminance-voltage characteristics of a light-emitting element according to an example. [Figure 62] FIG. 10 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 63] FIG. 10 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 64]10A and 10B are graphs illustrating electroluminescence spectra of light-emitting elements according to Examples. [Figure 65] FIG. 1 is a diagram illustrating an emission spectrum of a host material according to an example. [Figure 66] FIG. 10 is a graph showing luminance-current density characteristics of a light-emitting element according to an example. [Figure 67] FIG. 10 is a graph showing luminance-voltage characteristics of a light-emitting element according to an example. [Figure 68] FIG. 10 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 69] FIG. 10 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 70] 10A and 10B are graphs illustrating electroluminescence spectra of light-emitting elements according to Examples. [Figure 71] 4A and 4B are diagrams illustrating absorption spectra and emission spectra of guest materials according to an example. [Figure 72] 4A and 4B are diagrams illustrating absorption spectra and emission spectra of guest materials according to an example. [Figure 73] FIG. 2 is a diagram illustrating phosphorescent emission spectra of host materials according to an example. [Figure 74] FIG. 2 is a diagram illustrating phosphorescent emission spectra of host materials according to an example. [Figure 75] FIG. 2 is a diagram illustrating phosphorescent emission spectra of host materials according to an example. [Figure 76] FIG. 2 is a diagram illustrating phosphorescent emission spectra of host materials according to an example. [Figure 77] FIG. 10 is a graph showing luminance-current density characteristics of a light-emitting element according to an example. [Figure 78] FIG. 10 is a graph showing luminance-voltage characteristics of a light-emitting element according to an example. [Figure 79] FIG. 10 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 80] FIG. 10 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 81] 10A and 10B are graphs illustrating electroluminescence spectra of light-emitting elements according to Examples. [Figure 82]4A and 4B are diagrams illustrating absorption spectra and emission spectra of guest materials according to an example. [Figure 83] 10A to 10C are diagrams illustrating the results of a reliability test on a light-emitting element according to an example. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the above description, and the embodiments and details thereof may be modified without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the embodiments described below. The terms and conditions of the present invention are not to be construed as being limited to the content.

[0028] In addition, the position, size, range, etc. of each component shown in the drawings etc. are not necessarily shown in order to facilitate understanding. It may not represent the actual position, size, range, etc. Therefore, the disclosed invention The position, size, range, etc. are not necessarily limited to those disclosed in the drawings, etc.

[0029] In addition, in this specification, ordinal numbers such as 1st, 2nd, etc. are used for convenience, In some cases, the order of processes or layers may not be indicated. For example, "first" may be replaced with "second" or " can be appropriately replaced with "third" etc. The ordinal numbers used to identify an aspect of the present invention may not match. be.

[0030] In addition, in this specification and the like, when explaining the configuration of the invention using drawings, the same The reference numerals may be commonly used even among different drawings.

[0031] In addition, in this specification and the like, the terms "film" and "layer" are interchangeable. For example, the term "conductive layer" can be changed to the term "conductive film." Alternatively, for example, the term "insulating film" may be changed to "insulating layer" It may be possible to change the term to

[0032] In this specification and the like, the singlet excited state (S * ) is a single atom with excitation energy The S1 level is the lowest singlet excited energy level. The lowest excited energy level is the singlet excited state. (T * ) is a triplet state with excitation energy. The lowest excited energy level of the triplet excited state is In this specification and the like, the term "singlet excited state" is used simply to refer to a singlet excited energy level. Even when written as an energy level, it refers to the lowest singlet excited state or S1 level. In addition, when it is written as triplet excited state or triplet excited energy level, However, it may refer to the lowest triplet excited state or T1 level.

[0033] In this specification and the like, the fluorescent material refers to a material that emits light when it relaxes from a singlet excited state to a ground state. On the other hand, phosphorescent materials are materials that emit light in the visible light region from the triplet excited state to the ground state. When the material relaxes to the phosphorus state, it emits light in the visible light region at room temperature. An optical material is one of materials that can convert triplet excitation energy into visible light.

[0034] The phosphorescence energy or triplet excitation energy is the shortest wavelength side of the phosphorescence emission. It can be derived from the wavelength of the emission peak (including the shoulder). , and performing time-resolved photoluminescence in a low-temperature (e.g., 10 K) environment. The emission energy of thermally activated delayed fluorescence can be observed by It can be derived from the wavelength of the emission peak (including the shoulder) on the shortest wavelength side of the light.

[0035] In this specification and the like, room temperature refers to a temperature between 0°C and 40°C.

[0036] In this specification, the blue wavelength region refers to wavelengths of 400 nm or more and less than 500 nm. blue emission has at least one emission spectrum peak in this region. The green wavelength range is the wavelength range of 500 nm or more and less than 580 nm. Green emission is emission having at least one emission spectrum peak in this region. The red wavelength range is the wavelength range between 580 nm and 680 nm. The emission is an emission having at least one emission spectrum peak in the region.

[0037] (Embodiment 1) In this embodiment, a light-emitting element of one embodiment of the present invention will be described below with reference to FIGS. 1 and 2. Reveal.

[0038] <Configuration example of light-emitting element> First, the structure of a light-emitting element of one embodiment of the present invention will be described with reference to FIGS. This is explained below.

[0039] FIG. 1A is a schematic cross-sectional view of a light-emitting element 152 of one embodiment of the present invention.

[0040] The light emitting element 152 has a pair of electrodes (electrode 101 and electrode 102), and The EL layer 100 has at least a light-emitting layer 140. .

[0041] The EL layer 100 shown in FIG. 1A includes a hole injection layer 111, a cathode layer 112, a cathode layer 113, a cathode layer 114, a cathode layer 115, a cathode layer 116, a cathode layer 117, a cathode layer 118, a cathode layer 119 ... It has functional layers such as a hole transport layer 112, an electron transport layer 118, and an electron injection layer 119.

[0042] In this embodiment, of the pair of electrodes, electrode 101 is an anode, and electrode 1 Although the description will be given assuming that O2 is a cathode, the configuration of the light emitting element 152 is not limited to this. The electrode 101 is the cathode, the electrode 102 is the anode, and the layers between the electrodes are stacked in the reverse order. That is, from the anode side, the hole injection layer 111, the hole transport layer 112, and the light emitting layer 113 may be arranged in this order. The light-transmitting layer 140, the electron transporting layer 118, and the electron injection layer 119 may be stacked in this order. .

[0043] The configuration of the EL layer 100 is not limited to the configuration shown in FIG. 1(A). , a hole transport layer 112, an electron transport layer 118, and an electron injection layer 119. Alternatively, the EL layer 100 may be configured to have either a hole or electron injection layer. Reduce the barrier, improve the transportability of holes or electrons, or inhibit the transportability of holes or electrons or suppressing the quenching phenomenon caused by the electrode. The functional layers may each be a single layer or may be a laminate of multiple layers. It may be composed of

[0044] FIG. 1(B) is a cross-sectional view showing an example of the light-emitting layer 140 shown in FIG. 1(A). The light-emitting layer 140 shown in FIG. 1B includes a host material 141 and a guest material 142. The host material 141 includes an organic compound 141_1 and an organic compound 141_2.

[0045] Furthermore, a light-emitting organic material may be used as the guest material 142. The material is preferably a material that can emit phosphorescence (hereinafter also referred to as a phosphorescent material). In the following description, a configuration in which a phosphorescent material is used as the guest material 142 will be described. The guest material 142 may be interpreted as a phosphorescent material.

[0046] <Light-emitting mechanism of light-emitting elements> Next, the light emitting mechanism of the light emitting layer 140 will be described below.

[0047] The organic compound 141_1 and the organic compound 141_2 contained in the host material 141 in the light-emitting layer 140 The substance 141_2 is an exciplex (exciplex or Excitl Forms a nucleus (also called ex).

[0048] The combination of organic compound 141_1 and organic compound 141_2 forms an exciplex Any combination that can transport holes is acceptable, but one of them must have the function of transporting holes (hole transport property). The other compound must have the ability to transport electrons (electron transport properties). In this case, a donor-acceptor type exciplex is easily formed, This allows efficient formation of exciplexes.

[0049] In addition, as a combination of organic compound 141_1 and organic compound 141_2, one of them is The other highest occupied molecular orbital (Highest Occupied Molecular Orbital It has a HOMO level lower than the lowest unoccupied molecular orbital (HOMO) level, and Road (Lowest Unoccupied Molecular Orbital, LU It is preferred that the LUMO level be lower than the LUMO level.

[0050] For example, as shown in the energy band diagram in Figure 2(A), the organic compound 141_1 has an electron When the organic compound 141_1 has hole transport properties and the organic compound 141_2 has hole transport properties, The HOMO level of organic compound 141_2 is lower than the HOMO level of organic compound 141_2. The LUMO level of 41_1 is preferably lower than the LUMO level of the organic compound 141_2. stomach.

[0051] In this case, the exciplex formed by the organic compound 141_1 and the organic compound 141_2 is The energy difference between the LUMO level of organic compound 141_1 and the HOMO level of organic compound 141_2 Energy difference (ΔE Ex ) to form an exciplex with an excitation energy roughly equivalent to that of

[0052] In addition, the HOMO level of organic compound 141_1 and the HOMO level of organic compound 141_2 and the LUMO levels of organic compound 141_1 and organic compound 141_2. The difference between these is preferably 0.1 eV or more, more preferably 0.2 eV or more. By having this energy difference, The injected electron carriers and hole carriers are transferred to organic compound 141_1 and organic compound This is preferable because it makes it easier to inject the respective components into 141_2.

[0053] In FIG. 2(A), Host (141_1) represents the organic compound 141_1. Host(141_2) represents the organic compound 141_2, and Guest(142) represents the guest represents material 142, and ΔE Ex The LUMO level of organic compound 141_1 and organic compound 141 represents the energy difference between the HOMO level of _2 and ΔE B is the LUMO level of the guest material 142 represents the energy difference between the HOMO level of the organic compound 141_2 and that of the organic compound 141_2, and ΔE G is guest material 1 This is the notation and symbol that represents the energy difference between the LUMO level and the HOMO level of 42.

[0054] The guest material 142 emits light with a short wavelength and high emission energy. To achieve this, the energy difference (ΔE G On the other hand, in order to reduce the driving voltage of the light emitting element 152, It is preferable that the excitation energy is as small as possible. The excitation energy of the exciplex formed by the organic compound 141_1 and the organic compound 141_2 is small. Therefore, the LUMO level of the organic compound 141_1 and the LUMO level of the organic compound 141_2 are preferably The energy difference between the HOMO level of 1 and 2 (ΔE Ex ) is preferably small.

[0055] Since the guest material 142 is a phosphorescent light-emitting material, it emits triplet excitation energy. The triplet excited state has the function of being able to convert into the excited state. Therefore, the guest material 142 has a stable LUMO level and a stable HOMO level. The energy difference (ΔE G ) can emit light with lower energy than The energy difference (ΔE G ) is organic Energy difference between the LUMO level of organic compound 141_1 and the HOMO level of organic compound 141_2 (ΔE Ex ), the luminescence energy ( Abbreviation: ΔE Em ) or transition energy calculated from the absorption edge in the absorption spectrum (Abbreviation: ΔE abs ) is ΔE Ex If it is equal to or smaller than 14 The excited electrons from the exciplex formed between 1_1 and the organic compound 141_2 are transferred to the guest material 142. This invention demonstrates that the transfer of energy becomes possible and light can be emitted from the guest material 142. The researchers found that the ΔE G However, the luminescence energy of the guest material 142 Energy (ΔE Em ) or transition energy calculated from the absorption edge in the absorption spectrum -(ΔE abs ), direct electrical excitation of the guest material 142 requires ΔE G Since a large amount of electrical energy equivalent to this is required, the driving voltage of the light emitting element increases. However, in one embodiment of the present invention, ΔE Ex (ΔE G (smaller than The exciplex is electrically excited by the energy, and the guest material is excited by the energy transfer from the exciplex. To generate an excited state of the guest material 142, a low driving voltage and high efficiency were required. In other words, ΔE G However, the luminescence energy of the guest material 142 Energy (ΔE Em ) or the transition energy (ΔE abs ), for example, when the guest material is a blue light-emitting material, One aspect of this is particularly beneficial.

[0056] When the guest material 142 has a heavy metal, spin-orbit interaction (the spin angular momentum of electrons) and orbital angular momentum) promotes intersystem crossing between the singlet and triplet states. Therefore, the transition between the singlet ground state and the triplet excited state is forbidden in the guest material 142. In other words, the singlet ground state and triplet excited state of the guest material 142 may not be the same. The efficiency of the light emission and the probability of absorption related to the transition between The spin material 142 preferably contains a metal element with a large spin-orbit interaction, and particularly, platinum. Group elements (ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (O It is preferable that the metal oxide contains iridium (Ir), iridium (Ir), or platinum (Pt), among which iridium (Ir) is preferable. The presence of Cr in the ZnO atom enhances the absorption associated with the direct transition between the singlet ground state and the triplet excited state. This is preferable as it can increase the probability.

[0057] In order for the guest material 142 to be stable and highly reliable, the L The UMO level is preferably low, and for this purpose, the heavy metal atoms of the guest material 142 It is also preferable that the ligand to be coordinated to the nucleus has high electron-accepting property and a low LUMO level.

[0058] The guest material with the above structure is a molecule with a low LUMO level that easily accepts electrons. When the guest material 142 has a molecular structure that easily accepts electrons, The LUMO level of the material 142 may be lower than the LUMO level of the organic compound 141_1. Furthermore, ΔE G is ΔE Ex If the HOMO level of the guest material 142 is greater than The HOMO level of the organic compound 141_2 is lower than that of the guest material 142. The energy difference between the HOMO level of the guest material and the HOMO level of the organic compound 141_2 is The energy difference between the LUMO level of the material 142 and the LUMO level of the organic compound 141_1 is It becomes bigger.

[0059] Here, the LUMO level of the guest material 142 is higher than the LUMO level of the organic compound 141_1. The HOMO level of the guest material 142 is lower than that of the organic compound 141_2. When the potential is low, the carriers (holes and Among the electrons and the electrons, the electrons injected from the cathode are transported to the guest material 142 in the light-emitting layer 140. The holes injected from the anode are easily injected into the organic compound 141_2. Therefore, among the materials contained in the light-emitting layer 140, the material having the lowest LUMO level is the guest material 142, and the material with the highest HOMO level is the organic compound 141_2 In this case, the organic compound 141_2 and the guest material 142 form an exciplex. In particular, the HOMO level of the organic compound 141_2 and the LUMO level of the guest material 142 The energy difference between the levels (abbreviated as ΔE B ) is the emission energy of the guest material (ΔE Em ) As the excitation voltage becomes smaller than the threshold voltage, the excitation voltage formed between the organic compound 141_2 and the guest material 142 increases. In this case, the excited state is not generated by the guest material 142 alone. Therefore, the light emitting efficiency of the light emitting element is reduced.

[0060] The above reaction can be represented by the following formula (G1) or (G2).

[0061] D+ +G - → (D·G) * (G1) D+G * → (D·G) * (G2)

[0062] Formula (G1) shows that organic compound 141_2 accepts a hole (D + ), guest material 142 Accepts electrons (G - ) by which the organic compound 141_2 and the guest material 142 are excited into an exciplex. Body((D・G) * ) is produced. In addition, formula (G2) shows the reaction Material 142(G * ) interacts with the ground state organic compound 141_2(D) , the organic compound 141_2 and the guest material 142 are exciplexes ((D·G) * ) The organic compound 141_2 and the guest material 142 form an exciplex ((D·G) * ) By forming the guest material 142, the excited state (G * ) is difficult to generate. Wow.

[0063] The exciplex formed by the organic compound 141_2 and the guest material 142 is The energy difference (ΔE B ) The resulting exciplex has roughly the same excitation energy. The energy difference (ΔE B )but , the luminescence energy (ΔE Em ) or in the absorption spectrum The transition energy (ΔE abs ) or more, organic compound 1 The reaction of forming an exciplex between 41_2 and the guest material 142 can be suppressed, and the guest The present inventors have found that efficient light emission can be obtained from the material 142. In this case, ΔE B than ΔE abs Since the σ is small, the guest material 142 receives the excitation energy. It is easier to form an exciplex between the organic compound 141_2 and the guest material 142. The material 142 receives excitation energy and becomes excited, which has lower energy and is more stable. do.

[0064] As described above, the energy difference (Δ E G ) is the LUMO level of organic compound 141_1 and the HOMO level of organic compound 141_2. The energy difference (ΔE Ex ), the absorption spectrum of the guest material 142 The transition energy (ΔE abs ) is ΔE Ex is equivalent to or smaller, the excitation formed by organic compound 141_1 and organic compound 141_2 The excitation energy can be efficiently transferred from the complex to the guest material 142. As a result, a light-emitting element with low voltage and high efficiency can be obtained, which is one of the features of one embodiment of the present invention. In this case, ΔE abs ≦ΔE Ex <ΔE G (ΔE abs is ΔE Ex is less than or equal to Δ E Ex is ΔE G Therefore, ΔE abs is ΔE G Less than In other words, the mechanism of one aspect of the present invention is suitable for cases where ΔE G is ΔEabs Yo The mechanism of one aspect of the present invention is suitable when the guest material is larger than The energy difference (ΔE) between the LUMO level and the HOMO level of the material 142 G ) is the guest material 14 The transition energy (ΔE abs )twist, It is preferable that the luminescence energy ( ΔE Em ) is ΔE abs Since the LUM of guest material 142 is equal to or smaller than The energy difference between the O level and the HOMO level (ΔE G ) is the luminescence of the guest material 142. Energy (ΔE Em ) is preferably 0.4 eV or more larger. -(ΔE Em ) is the emission peak (maximum or shortest wavelength) on the emission spectrum. can be derived from the wavelength of the

[0065] Furthermore, the LUMO level of the guest material 142 is higher than that of the organic compound 141_1. If it is lower than ΔE abs ≦ΔE B (ΔE abs is ΔE B below), or ΔE Em ≦ΔE B (ΔE Em is ΔE B Therefore, ΔE abs ≦ΔE B <ΔE Ex <ΔE G (ΔE abs is ΔE B is less than or equal to ΔE B is ΔE Ex Less than Saku, ΔE Ex is ΔEG smaller), or ΔE Em ≦ΔE B <ΔE Ex <ΔE G ( ΔE Em is ΔE B is less than or equal to ΔE B is ΔE Ex Smaller ΔE Ex is ΔE G Smaller These conditions are also important findings in one embodiment of the present invention.

[0066] The emission wavelength of the guest material 142 becomes shorter, and the emission energy (ΔE Em )but The larger the energy difference (Δ E G ) becomes larger, and accordingly, a large However, in one embodiment of the present invention, the guest material 142 The transition energy (ΔE abs ) is ΔE Ex If it is equal to or smaller than ΔE G ΔE is smaller than Ex Amount of energy Since the guest material 142 can be excited by the excitation current, the power consumption of the light-emitting element can be reduced. Therefore, the absorption edge calculated from the absorption spectrum of the guest material 142 can be The transition energy (ΔE abs ) and the LUMO and HOMO levels of the guest material 142 The energy difference (ΔE G ) and the larger the energy difference between In the case of a guest material exhibiting light emission of the above formula (1), the effect of the light-emitting mechanism of one embodiment of the present invention becomes remarkable.

[0067] However, the transition energy calculated from the absorption edge in the absorption spectrum of the guest material 142 is Gee (ΔE abs ) becomes smaller, the luminescence energy of the guest material 142 also becomes smaller. Therefore, it becomes difficult to obtain light emission having high energy such as blue light emission. That is, ΔE abs and ΔE G If the difference becomes too large, high energy light such as blue light will not be emitted. It becomes difficult to obtain light emission with high energy.

[0068] From these results, the energy difference between the LUMO level and the HOMO level of the guest material 142 is (ΔE G ) is the transition energy calculated from the absorption edge in the absorption spectrum of the guest material 142. Energy (ΔE abs ) and it is preferable that the value is larger in the range of 0.4 eV or more and 0.8 eV or less. It is more preferable that the guest material 1 is large in the range of 0.5 eV or more and 0.8 eV or less. The luminescence energy (ΔE Em ) is ΔE abs Equal to or smaller than Therefore, the energy difference (ΔE G )teeth, The luminescence energy (ΔE Em ) from 0.4eV to 0.8e It is preferable that the value is large in the range of 0.5 eV or less, and it is preferable that the value is large in the range of 0.5 eV or more and 0.8 eV or less. More preferable.

[0069] In addition, the LUMO level of the guest material 142 and the LUMO level of the organic compound 141_1 The difference is preferably 0.05 eV or more and 0.4 eV or less. This has the effect of extending the life of the device, but if the LUMO level of the guest material is too low, ΔEB In addition, the HOMO level of the guest material 142 and the The difference between the HOMO level of the organic compound 141_2 and that of the organic compound 141_3 is preferably 0.05 eV or more. It is preferably 0.1 eV or more, and more preferably 0.2 eV or more. By correlating the energy levels, hole carriers are easily injected into the organic compound 141_2. This is preferable because it reduces the

[0070] In addition, the LUMO level of organic compound 141_1 and the HOMO level of organic compound 141_2 The energy difference (ΔE Ex ) is the LUMO level and HOMO level of the organic compound 141_1. and the energy difference between the LUMO level and the HOMO level of the organic compound 141_2. -Because the difference is smaller than the organic compound 141_1 and the organic compound 141_2, Forming an exciplex is more energetically stable than forming an excited state in the molecule. , the energy difference between the LUMO level and the HOMO level of the guest material 142 (ΔE G ) but organic Energy of the LUMO level of compound 141_1 and the HOMO level of organic compound 141_2 Difference (ΔE Ex ), the carriers (holes and electrons) injected into the light-emitting layer 140 The excited state formed by recombination is organic compound 141_1 and organic compound 141_2. The exciplex formed by the above is energetically stable. Most of the excited states are formed by organic compounds 141_1 and 141_2. Therefore, according to one embodiment of the present invention, By facilitating the transfer of excitation energy from the exciplex to the guest material 142, The driving voltage of the optical element can be reduced, and the light emission efficiency can be increased.

[0071] The HOMO level of the guest material 142 is higher than that of the organic compound 141_1. It can be high or low.

[0072] In addition, the LUMO level of the guest material 142 is higher than that of the organic compound 141_1. Since the guest material 142 has a low conductivity, it functions as an electron trap in the light-emitting layer 140. When the guest material 142 functions as an electron trap, the carrier balance in the light-emitting layer is improved. This is preferable because it is possible to easily control the temperature and the effect of extending the life can be obtained.

[0073] In addition, the combination of organic compound 141_1 and organic compound 141_2 has hole transport properties. When a compound having electron transport properties is used in combination with a compound having electron transport properties, the mixing ratio Specifically, the carrier balance can be easily controlled by using a material having hole transport properties. The compound having electron transport properties:compound having electron transport properties is preferably in the range of 1:9 to 9:1 (weight ratio). In addition, by having this configuration, the carrier balance can be easily controlled. In addition, the carrier recombination region can be easily controlled.

[0074] The exciplex formed by organic compound 141_1 and organic compound 141_2 is The organic 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 excited complex has a small difference between the singlet and triplet excited energy levels. Therefore, the exciplex formed by the organic compound 141_1 and the organic compound 141_2 is The difference between the singlet and triplet excited energy levels is preferably greater than 0 eV. It is preferably 0.2 eV or less, and more preferably more than 0 eV and 0.1 eV or less.

[0075] Here, the organic compound 141_1, the organic compound 141_2, and the gel The correlation between the energy levels of the SiO2 and the SiO2 material 142 is shown in FIG. 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) ·Exciplex: Excitation complex (organic compound 141_1 and organic compound 141_2) ·S PH1 : S1 level of the host material (organic compound 141_1) T PH1 : T1 level of the host material (organic compound 141_1) ·S PH2 : S1 level of the host material (organic compound 141_2) T PH2 : T1 level of the host material (organic compound 141_2) ·S PG : S1 level of guest material 142 (phosphorescent material) T PG : T1 level of guest material 142 (phosphorescent material) ·S PE : S1 level of the exciplex T PE :T1 level of exciplex

[0076] In the light-emitting element of one embodiment of the present invention, the organic compound 141_1 contained in the light-emitting layer 140 The organic compound 141_2 forms an exciplex. The lowest level of the singlet excited state of the exciplex is Rank (S PE ) and the lowest triplet excited state of the exciplex (TPE ) are adjacent to each other (See Route E7 in Figure 2(B)).

[0077] An exciplex is an excited state consisting of two substances. In the case of photoexcitation, the excited state formed by the interaction of one substance with another substance in its ground state, and When the two substances that formed the exciplex return to the ground state by emitting light, In the case of electrical excitation, when one of them is excited, it quickly Alternatively, one atom can transfer a hole and the other an electron. They can receive electrons and interact with each other to quickly form exciplexes. In the case of Therefore, most of the excited states in the light-emitting layer 140 exist as exciplexes. It is possible to obtain the excited energy level (S E or T E ) forms an exciplex The S1 level (S PH1 and S PH2 ) and therefore the host material 141 This allows the driving voltage of the light emitting element 152 to be reduced. can be reduced.

[0078] And the (S PE ) and (T PE ) and the energy of the guest material 142 The lowest triplet excited state (T PG ) to obtain luminescence ( See Figure 2(B) Routes E8 and E9).

[0079] In addition, the T1 level of the exciplex (T PE ) is the T1 level (T PG )twist By achieving such a relationship in the T1 level, the single-layer structure of the generated exciplex can be obtained. The single and triplet excitation energies are calculated from the S1 level (S PE ) and T1 level (T PE ) to the T1 level (T PG ) energy transfer to This can be done.

[0080] By configuring the light-emitting layer 140 as described above, the guest material 142 (phosphorescent material ) can be efficiently obtained.

[0081] The above-described processes of Route E7, Route E8, and Route E9 are referred to as the processes of Route E6, Route E7, Route E8, and Route E9 in this specification. ExTET (Exciplex-Triplet Energy Transfer) In other words, the light-emitting layer 140 converts the guest material 142 from the exciplex. In this case, excitation energy is donated to T PE From S PE Inverse Interterm to The crossover efficiency does not need to be high, PE The quantum yield of light emission from the material does not need to be high. A wide range of choices is possible.

[0082] The above reactions can be expressed by the following formulas (G3) to (G5).

[0083] D + +A - → (D·A) * (G3) (D·A) * +G → D+A+G * (G4) G *→ G+hν (G5)

[0084] Formula (G3) shows that either organic compound 141_1 or organic compound 141_2 receives a hole. Take (D + ), and the other accepts electrons (A - ) by organic compound 141_1 and organic Compound 141_2 is an exciplex ((D·A) * ) is produced by the reaction shown in formula (G4). is the exciplex ((D A) * Energy transfer occurs from the guest material 142 (G) to the guest material 142 (G). The excited states (G * ) is produced by the reaction. Then, as shown in equation (G5), The guest material 142 in the excited state emits light (hν).

[0085] In order to efficiently transfer excitation energy from the exciplex to the guest material 142, , the T1 level of the exciplex (T PE ) is each of the compounds constituting the host material that forms the exciplex. lower than the T1 level of the organic compounds (organic compounds 141_1 and 141_2). This makes it possible to query the triplet excitation energy of the exciplex by each organic compound. This makes it difficult for the energy to be broken down, and energy transfer to the guest material 142 occurs efficiently.

[0086] In addition, when the organic compound 141_2 has a skeleton with a strong donor property, it is possible to inject the organic compound 141_2 into the light-emitting layer 140. The holes are easily injected into the organic compound 141_2 and transported. When 141_1 has a skeleton with a strong acceptor property, the electrons injected into the light-emitting layer 140 , electrons are injected into the organic compound 141_1 and are easily transported. , and holes are injected into organic compound 141_2, respectively, and organic compound 141_1 and It is easy to form an exciplex with the organic compound 141_2.

[0087] By configuring the light-emitting layer 140 as described above, light emission from the guest material 142 of the light-emitting layer 140 can be obtained efficiently.

[0088] <Energy transfer mechanism> Next, the control of the energy transfer process between the host material 141 and the guest material 142 The mechanism of energy transfer between molecules is the Förster mechanism (bipolar Two mechanisms have been proposed: the electron-dipole interaction (electron-dipole interaction) and the Dexter mechanism (electron exchange interaction). Here, energy transfer between the host material 141 and the guest material 142 is The process is similar when the host material 141 is an exciplex.

[0089] <Förster mechanism> In the Förster mechanism, energy transfer does not require direct contact between molecules, but occurs via the host Energy transfer occurs through the resonance phenomenon of dipole vibration between the material 141 and the guest material 142. The host material 141 transfers energy to the guest material 142 due to the resonance phenomenon of the dipole vibration. The excited host material 141 returns to the ground state, and the guest material 14 2 becomes excited. The rate constant of the Förster mechanism is k h*→g is shown in formula (1) .

[0090]

number

[0091] In formula (1), ν represents the frequency, and f' h (ν) is the standard of the host material 141 The emission spectrum (or the fluorescence spectrum when discussing energy transfer from the singlet excited state) spectrum, and phosphorescence spectrum when discussing energy transfer from triplet excited states), ε g (ν) represents the molar extinction coefficient of the guest material 142, N represents Avogadro's number, and n represents the refractive index of the medium, and R represents the intermolecular distance between the host material 141 and the guest material 142. where τ represents the measured lifetime of the excited state (fluorescence lifetime or phosphorescence lifetime), and c represents the speed of light. , φ is the luminescence quantum yield (fluorescence quantum yield when discussing energy transfer from the singlet excited state) represents the phosphorescence quantum yield when discussing energy transfer from the triplet excited state, and K 2 teeth , a coefficient (between 0 and 142) that represents the orientation of the transition dipole moments of the host material 141 and the guest material 142. In the case of random orientation, K 2 =2 / 3.

[0092] Dexter Mechanism In the Dexter mechanism, the host material 141 and the guest material 142 are bonded together, causing orbital overlap. The electrons in the excited host material 141 and the guest material 142 are in the ground state and approach the effective distance. Energy transfer occurs through the exchange of electrons with 2. The rate constant for the Dexter mechanism is k h*→g is shown in equation (2).

[0093]

number

[0094] In equation (2), h is Planck's constant, and K is a constant with the dimension of energy. where ν represents the frequency and f' h (ν) is the normalized emission spectrum of the host material 141. Spectra (fluorescence spectrum when discussing energy transfer from singlet excited states, triplet When discussing energy transfer from an excited state, it represents the phosphorescence spectrum, and ε' g (ν) is , represents the normalized absorption spectrum of the guest material 142, L represents the effective molecular radius, R represents the intermolecular distance between the host material 141 and the guest material 142 .

[0095] Here, the energy transfer efficiency φ from the host material 141 to the guest material 142 ET is a number It is expressed by equation (3). r The emission process of the host material 141 (energy from the singlet excited state) When discussing energy transfer, we use fluorescence; when discussing energy transfer from triplet excited states, we use phosphorus. represents the rate constant of photon transport, k n is the non-radiative process (thermal deactivation and intersystem crossing) of the host material 141. represents the rate constant, and τ represents the measured lifetime of the excited state of the host material 141.

[0096]

number

[0097] From equation (3), the energy transfer efficiency φ ET To increase the energy transfer rate, Degree constant k h*→g By increasing the rate constant k r +k n (=1 / τ) is relatively You know the smaller the better.

[0098] <Concept for enhancing energy transfer> In the energy transfer by the Förster mechanism, the energy transfer efficiency φ ET is the amount quantum yield φ (fluorescence quantum yield when discussing energy transfer from singlet excited states, triplet When discussing energy transfer from the excited state, a higher phosphorescence quantum yield is better. Emission spectra of host materials 141 (when discussing energy transfer from singlet excited states) is the fluorescence spectrum) and the absorption spectrum of the guest material 142 (from the singlet ground state to the triplet excitation). It is preferable that the overlap with the absorption corresponding to the transition to the excited state is large. It is also preferable that the molar absorption coefficient of the host material 142 is high. This means that the spectrum overlaps with the absorption band appearing on the longest wavelength side of the guest material 142.

[0099] In addition, in the energy transfer by the Dexter mechanism, the rate constant k h*→g Enlarge In this study, the emission spectrum of the host material 141 (energy transfer from the singlet excited state) was discussed. When discussing energy transfer from triplet excited states, we use the fluorescence spectrum. Absorption spectra of the 142 (singlet ground state to triplet excited state) and guest material Therefore, the efficiency of energy transfer is The optimization is performed on the emission spectrum of the host material 141 and the longest wavelength side of the guest material 142. This is achieved by the overlap of the absorption bands of the

[0100] Similar to the energy transfer from the host material 141 to the guest material 142, an exciplex The energy transfer process from the ion to the guest material142 was also investigated using the Förster mechanism and the Deca- Energy transfer occurs via both mechanisms of the star mechanism.

[0101] Therefore, one embodiment of the present invention is to provide an energy source that can efficiently transfer energy to the guest material 142. Organic compounds that combine to form exciplexes that function as energy donors. A light-emitting element having a compound 141_1 and an organic compound 141_2 as a host material 141 is provided. The exciplex formed by organic compound 141_1 and organic compound 141_2 is 41_1 and organic compound 141_2 can be formed at lower excitation energy than the excited state of the simple substance. Therefore, the driving voltage of the light emitting element 152 can be reduced. In addition, the guest material acts as an energy acceptor from the singlet excited energy level of the exciplex. To facilitate energy transfer to the triplet excited energy level of 142, the excitation The emission spectrum of the complex and the longest wavelength side (low energy) of the absorption spectrum of the guest material 142 It is preferable that the emission spectrum and absorption band appearing on the other side (the upper side) overlap. By achieving this spectral relationship, the generation efficiency of the triplet excited state of the guest material 142 can be increased. The exciplex generated in the light-emitting layer 140 has a singlet excited energy level. The excited triplet energy level is close to the excited triplet energy level, which allows the emission of the exciplex. The optical spectrum and the absorption band appearing on the longest wavelength side (lowest energy side) of the guest material 142 are overlapped. By this reaction, the triplet excited energy level of the exciplex is converted to the triplet excited energy level of the guest material 142. This also makes it easier for energy to transfer to the energy level.

[0102] <Material> Next, components of a light-emitting element according to one embodiment of the present invention will be described in detail below.

[0103] <Light-emitting layer> In the light-emitting layer 140, the host material 141 is present in the largest amount by weight, and the guest material 142 The phosphorescent material is dispersed in the host material 141. The T1 level of the organic compound 141_1 and the organic compound 141_2 is It is preferable that the T1 level is higher than the T1 level of the material (guest material 142).

[0104] As the organic compound 141_1, a material having a higher electron transporting property than a hole transporting property can be used. 1×10 -6 cm 2 It is preferable that the material has an electron mobility of 1 / Vs or more. Nitrogen-containing heteroaromatic compounds are materials that readily accept electrons (materials with electron transport properties). Compounds with π-electron-deficient heteroaromatic ring skeletons, such as Specifically, quinoline ligands, benzoquinoline ligands, octadecyl benzoates, etc. can be used. Metal complexes with oxazole or thiazole ligands, and oxadiazole derivatives Conductors, triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzo Quinoxaline derivatives, phenanthroline derivatives, pyridine derivatives, bipyridine derivatives, Examples of such compounds include imidine derivatives and triazine derivatives.

[0105] Specifically, for example, tris(8-quinolinolato)aluminum(III) (abbreviation: A lq), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Al mq3), bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation :BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)a Aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Metal complexes having a quinoline skeleton or a benzoquinoline skeleton, such as Znq, In addition, bis[2-(2-benzoxazolyl)phenolato]zinc(II)( Abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phenolato]zinc(II) ( Metal complexes with oxazole or thiazole ligands, such as ZnBTZ In addition to metal complexes, 2-(4-biphenylyl)-5 -(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD) and 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazo OXD-7), 9-[4-(5-phenyl-1,3, 4-Oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11) , 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)- 1,2,4-Triazole (abbreviation: TAZ), 9-[4-(4,5-diphenyl-4H- 1,2,4-triazol-3-yl)phenyl]-9H-carbazole (abbreviation: CzT AZ1), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl -1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophene- 4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBI m-II), bathophenanthroline (abbreviation: BPhen), bathocuproine (abbreviation: B Heterocyclic compounds such as 2-[3-(dibenzothiophen-4-yl)phenyl] Dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-( Dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxalate (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazole-9-yl) 2mCzBPDB q), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]di Benzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzo[f,h]quinoxaline] [4-( ... TPDBq-II) and 6-[3-(dibenzothiophen-4-yl)phenyl]di Benzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 2-[3-(3, 9'-bi-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (Abbreviation: 2mCzCzPDBq), 4,6-bis[3-(phenanthrene-9-yl)phenyl] phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-diphenyl)pyrimidine 4,6-zothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), Bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mC Heterocyclic compounds with diazine skeletons such as 2-{4-[3-(N-phenyl)-2-(4 ... (9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}- Triazines such as 4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn) Heterocyclic compounds with an amine skeleton and 3,5-bis[3-(9H-carbazol-9-yl] )phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridinyl) Heterocyclization of pyridine skeletons such as [(phenyl)phenyl]benzene (abbreviation: TmPyPB) Compound, 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: Heteroaromatic compounds such as BzOs can also be used. The triazine skeleton, diazine (pyrimidine, pyrazine, pyridazine) skeleton, or pyridazine skeleton Heterocyclic compounds having an azine skeleton are preferred because they are stable and highly reliable. Heterocyclic compounds having the above structure have high electron transport properties and contribute to reducing the driving voltage. 2,5-pyridinediyl) (abbreviation: PPy), poly[(9,9-dihexylfluorene- 2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviation: PF-Py), poly [(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine Polymer compounds such as PF-BPy (PF-6,6'-diyl) can also be used. The substances mentioned here are mainly 1×10 -6 cm 2 / Vs or higher electron mobility It should be noted that any substance other than those mentioned above that has a higher electron transporting property than holes can be used. It's okay.

[0106] The organic compound 141_2 is a compound that can form an exciplex with the organic compound 141_1. Specifically, a π-electron-rich heteroaromatic ring skeleton or an aromatic amine skeleton is preferred. It is preferable that the compound has a highly donor skeleton. Examples include dibenzothiophene derivatives, dibenzofuran derivatives, and carbazole derivatives. In this case, organic compound 141_1 and organic compound 141_ The emission peak of the exciplex formed with 2 is the triplet ML of the guest material 142 (phosphorescent material). Absorption of CT (Metal to Ligand Charge Transfer) transition The organic compound 141_1, the organic compound 142_2, and the organic compound 143_3 were used to overlap the absorption band of the longest wavelength. It is preferable to select an organic compound 141_2 and a guest material 142 (phosphorescent material). This allows the light-emitting element to have a dramatically improved luminous efficiency. When a thermally activated delayed fluorescent material is used instead of the conventional material, the absorption band at the longest wavelength side is a single band. It is preferable that the absorption band is

[0107] As the organic compound 141_2, the following hole transporting materials can be used.

[0108] As the hole transporting material, a material having a higher hole transporting property than an electron transporting property can be used. x10 -6 cm 2 It is preferable that the material has a hole mobility of 1 / Vs or more. The compounds are prepared using aromatic amines, carbazole derivatives, aromatic hydrocarbons, stilbene derivatives, etc. The hole transporting material may be a polymer compound.

[0109] As the material having high hole transporting properties, specifically, aromatic amine compounds such as N, N'-Di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviated as DT DPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenyla N,N'-bis[4-[bis(3-methylphenyl) {N,N'-diphenyl-(1,1'-biphenyl)-4,4' -diamine (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylamino) [phenyl]-N-phenylamino]benzene (abbreviation: DPA3B), etc. .

[0110] Specific examples of carbazole derivatives include 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 [N-(1-naphthyl)amino]-9-phenylcarbazole (abbreviation :PCzTPN2), 3-[N-(9-phenylcarbazol-3-yl)-N-phenyl 3,6-bis[N- (9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazol PCzPCA2, 3-[N-(1-naphthyl)-N-(9-phenylcarbazone] [carbazol-3-yl]amino]-9-phenylcarbazole (abbreviation: PCzPCN1) The following can be mentioned:

[0111] Other carbazole derivatives include 4,4'-di(N-carbazolyl)biphene. Nyl (abbreviation: CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzoyl Zene (abbreviation: TCPB), 9-[4-(10-phenyl-9-anthryl)phenyl]- 9H-Carbazole (abbreviation: CzPA), 1,4-bis[4-(N-carbazolyl)phenyl] nyl]-2,3,5,6-tetraphenylbenzene, etc. can be used.

[0112] Furthermore, examples of aromatic hydrocarbons include 2-tert-butyl-9,10-di(2- naphthyl)anthracene (abbreviation: t-BuDNA), 2-tert-butyl-9,10- Di(1-naphthyl)anthracene, 9,10-bis(3,5-diphenylphenyl)anthracene thracene (abbreviation: DPPA), 2-tert-butyl-9,10-bis(4-phenylphenyl) phenyl)anthracene (abbreviation: t-BuDBA), 9,10-di(2-naphthyl)anthracene Helical anthracene (abbreviated as DNA), 9,10-diphenylanthracene (abbreviated as DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAnth), 9,10-bis(4- Methyl-1-naphthyl)anthracene (abbreviation: DMNA), 2-tert-butyl-9, 10-bis[2-(1-naphthyl)phenyl]anthracene, 9,10-bis[2-(1 -naphthyl)phenyl]anthracene, 2,3,6,7-tetramethyl-9,10-di( 1-naphthyl)anthracene, 2,3,6,7-tetramethyl-9,10-di(2-naphthyl)anthracene thyl)anthracene, 9,9'-bianthryl, 10,10'-diphenyl-9,9'- Bianthryl, 10,10'-bis(2-phenylphenyl)-9,9'-bianthryl , 10,10'-bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9' -Bianthryl, anthracene, tetracene, rubrene, perylene, 2,5,8,11- tetra(tert-butyl)perylene, etc. In addition, pentacene, Years etc. can also be used. In this way, 1 × 10 -6 cm 2 Hole mobility above / Vs It is more preferable to use an aromatic hydrocarbon having 14 to 42 carbon atoms.

[0113] The aromatic hydrocarbon may have a vinyl skeleton. Examples of aromatic hydrocarbons include 4,4'-bis(2,2-diphenylvinyl)biphenyl. (abbreviation: DPVBi), 9,10-bis[4-(2,2-diphenylvinyl)phenyl] anthracene (abbreviation: DPVPA), etc.

[0114] In addition, poly(N-vinylcarbazole) (abbreviation: PVK) and poly(4-vinyltriphenyl ether) Nylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenyl amino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide]( abbreviation: PTPDMA), poly[N,N'-bis(4-butylphenyl)-N,N'-bis Polymer compounds such as [(phenyl)benzidine] (abbreviation: Poly-TPD) can also be used. can.

[0115] Furthermore, examples of materials with high hole transport properties include 4,4'-bis[N-(1-naphthyl)-2-methyl-2-propanol]. N,N'-(phenyl)-N-phenylamino]biphenyl (abbreviation: NPB or α-NPD) Bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4, 4'-diamine (abbreviation: TPD), 4,4',4''-tris(carbazol-9-yl) ) triphenylamine (abbreviation: TCTA), 4,4',4''-tris[N-(1-naphthyl) 4,4-Triphenylamine (abbreviation: 1'-TNATA) ',4''-Tris(N,N-diphenylamino)triphenylamine (abbreviation: TDAT A), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino] Triphenylamine (abbreviation: MTDATA), 4,4'-bis[N-(spiro-9,9' -bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4 -phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenyl Nylamine (abbreviation: mBPAFLP), N-(9,9-dimethyl-9H-fluorene-2 -yl)-N-{9,9-dimethyl-2-[N'-phenyl-N'-(9,9-dimethyl -9H-fluoren-2-yl)amino]-9H-fluoren-7-yl}phenylamino N-(9,9-dimethyl-2-diphenylamino-9H- Fluoren-7-yl)diphenylamine (abbreviation: DPNF), 2-[N-(4-diphenyl) N-phenylaminophenyl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: DPASF), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl) Triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9- Phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1B) P), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl) Triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''- (9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCBN BB), 4-phenyldiphenyl-(9-phenyl-9H-carbazol-3-yl)a amine (abbreviation: PCA1BP), N,N'-bis(9-phenylcarbazol-3-yl) -N,N'-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N,N', N''-triphenyl-N,N',N''-tris(9-phenylcarbazole-3-yl) N-(4-biphenyl)benzene-1,3,5-triamine (abbreviation: PCA3B) -N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-chlor PCBiF, N-(1,1'-biphenyl-4-yl) -N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-di Methyl-9H-fluoren-2-amine (abbreviation: PCBBiF), 9,9-dimethyl-N -phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl] Fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl -9H-carbazol-3-yl)phenyl]spiro-9,9'-bifluorene-2-a PCBASF, 2-[N-(9-phenylcarbazol-3-yl)-N -phenylamino]spiro-9,9'-bifluorene (abbreviation: PCASF), 2,7-bi Spiro-9,9'-[N-(4-diphenylaminophenyl)-N-phenylamino] -bifluorene (abbreviation: DPA2SF), N-[4-(9H-carbazol-9-yl) Phenyl]-N-(4-phenyl)phenylaniline (abbreviation: YGA1BP), N,N' -Bis[4-(carbazol-9-yl)phenyl]-N,N'-diphenyl-9,9- Aromatic amine compounds such as dimethylfluorene-2,7-diamine (abbreviation: YGA2F) Also, 3-[4-(1-naphthyl)-phenyl]-9-phenyl 3-[4-(9-phenanthryl)-phenyl]-9H-carbazole (abbreviation: PCPN), 3,3'-bis(9-phenyl-9H-carbazole) -phenyl-9H-carbazole) (abbreviation: PCCP), 1,3-bis(N-carbazole) mCP, 3,6-bis(3,5-diphenylphenyl)-9-fluorobenzene Phenylcarbazole (abbreviation: CzTP), 3,6-di(9H-carbazol-9-yl) -9-phenyl-9H-carbazole (abbreviation: PhCzGI), 2,8-di(9H-carbazole) 4-{3-[3- (9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran ( Abbreviation: mmDBFFLBi-II), 4,4',4''-(benzene-1,3,5-trimethyl 1,3,5-tri(dibenzofuran) (abbreviation: DBF3P-II), 2,8-diphenylthiophen-4-yl)-benzene (abbreviation: DBT3P-II) -4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiof fluorene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluorene- 9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV) , 4-[3-(triphenylen-2-yl)phenyl]dibenzothiophene (abbreviation: mD Amine compounds such as BTP-II, carbazole compounds, thiophene compounds, furan compounds, fluorene compounds, triphenylene compounds, phenanthrene compounds, etc. Among the compounds mentioned above, those having a pyrrole skeleton, a furan skeleton, a thiophene skeleton, an aromatic Compounds having an aromatic amine skeleton are preferred because they are stable and highly reliable. The compound having the formula (I) has high hole transporting properties and contributes to reducing the driving voltage.

[0116] The guest material 142 (phosphorescent material) is an iridium, rhodium, or platinum-based organic material. Metal complexes, or metal complexes, among which organic iridium complexes, e.g., iridium The orthometalated complex is preferably a 4H-triazole. Ligand, 1H-triazole ligand, imidazole ligand, pyridine ligand, pyrimidine The metal complexes include a pyrazine ligand, an isoquinoline ligand, and the like. Examples include platinum complexes having porphyrin ligands.

[0117] In addition, as the guest material 142 (phosphorescent material), the LUMO level of the organic compound 141_1 It has a lower LUMO level and a lower HOMO level than the HOMO level of organic compound 141_2. The organic compound 141_1, the organic compound 141_2, and the guest material 14 It is preferable to select 2 (phosphorescent material). This allows for high luminous efficiency and low driving voltage. The light emitting element may be a light emitting element that moves.

[0118] Examples of substances having a blue or green emission peak include tris{2-[5-(2 -methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazo {3-yl-κN2]phenyl-κC}iridium(III) (abbreviation: Ir(mpp tz-dmp)3), tris(5-methyl-3,4-diphenyl-4H-1,2,4-trimethyl- Triazolato)iridium(III) (abbreviation: Ir(Mptz)3), tris[4-(3- Biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]i Iridium(III) (abbreviation: Ir(iPrptz-3b)3), tris[3-(5-biphenyl] (phenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]irid Ir(III) (abbreviated as Ir(iPr5btz)3), a 4H-triazole skeleton and organometallic iridium complexes with tris[3-methyl-1-(2-methylphenyl) -5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: Ir (Mptz1-mp)3), tris(1-methyl-5-phenyl-3-propyl-1H- 1,2,4-Triazolate)iridium(III) (abbreviation: Ir(Prtz1-Me) 3) and fac-triazole-based organometallic iridium complexes. S[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]isopropyl Iridium(III) (abbreviation: Ir(iPrpmi)3), tris[3-(2,6-dimethyl phenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(I II) Imidazole skeleton-containing compounds such as Ir(dmpimpt-Me) Organic metal iridium complexes and bis[2-(4',6'-difluorophenyl)pyridinato- N,C 2’ ]iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation: FI r6), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ]Ili Dium(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis (Trifluoromethyl)phenyl]pyridinato-N,C 2’}Iridium(III) pico Ir(CF3ppy)2(pic) (fluorophenyl)pyridinato-N,C 2’ ]Iridium(III) acetylacetonate (abbreviation: FIr(acac)) Among the above, 4H-triazole is an organometallic iridium complex. a nitrogen-containing five-membered heterocyclic skeleton such as a 1H-triazole skeleton and an imidazole skeleton; The organometallic iridium complexes have high triplet excitation energy and are highly reliable and highly efficient. It is particularly preferred because it is also excellent in

[0119] Furthermore, examples of substances having a green or yellow emission peak include tris(4-methylphenyl) Ir(mppm)3, Tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: I r(tBuppm)3), (acetylacetonato)bis(6-methyl-4-phenylpyridine) Iridium(III) (abbreviation: Ir(mppm)2(acac)), (acetylacetonate ruacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium( III) (Abbreviation: Ir(tBuppm)2(acac)), (acetylacetonato)bis [4-(2-norbornyl)-6-phenylpyrimidinato]iridium(III) (abbreviation : Ir(nbppm)2(acac)), (acetylacetonato)bis[5-methyl-6 -(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: Ir(mpmppm)2(acac)), (acetylacetonato)bis{4,6-dimethyl 2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN3]phenyl- κC}iridium(III) (abbreviation: Ir(dmppm-dmp)2(acac)), ( acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III)( Organometallic iridium compounds with pyrimidine skeletons, such as Ir(dppm)2(acac) complexes and (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazine Iridium(III) (abbreviation: Ir(mppr-Me)2(acac)), (acetyl arylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridide Pyrazine skeletons such as Ir(III) (abbreviation: Ir(mppr-iPr)2(acac)) Organometallic iridium complexes and tris(2-phenylpyridinato-N,C 2’ ) Iridium(III) (abbreviation: Ir(ppy)3), bis(2-phenylpyridinato-N ,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(ppy)2(ac ac)), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: Ir(bzq)2(acac)), tris(benzo[h]quinolinato)iridium Ir(III) (abbreviation: Ir(bzq)3), tris(2-phenylquinolinato-N,C 2 ’ ) Iridium(III) (abbreviation: Ir(pq)3), bis(2-phenylquinolinato- N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(pq)2(ac Organometallic iridium complexes with pyridine skeletons such as bis(2,4-difluoromethyl) Phenyl-1,3-oxazolato-N,C 2’ ) Iridium(III) acetylacetoner Ir(dpo)2(acac)), bis{2-[4'-(perfluorophenyl) (phenyl)pyridinato-N,C 2’}Iridium(III) acetylacetonate( Abbreviation: Ir(p-PF-ph)2(acac)), bis(2-phenylbenzothiazol- -N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(bt)2(a In addition to organometallic iridium complexes such as tris(acetylacetonato)(monophenyl) Anthroline) terbium(III) (abbreviation: Tb(acac)3(Phen)) Among the above, organometallic iridium complexes having a pyrimidine skeleton are Dium complexes are particularly preferred because they are remarkably excellent in reliability and luminous efficiency.

[0120] Furthermore, examples of substances having 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 (5mdppm)2(dpm)), bis[4,6-di(naphthalen-1-yl)pyrimidinyl] Nato](dipivaloylmethanato)iridium(III) (abbreviation: Ir(d1npm)2( Organometallic iridium complexes with pyrimidine skeletons, such as (acetylacetonyl acetone) Iridium(III) (abbreviation: I r(tppr)2(acac)), bis(2,3,5-triphenylpyrazinate)(dipyr Valoylmethanato)iridium(III) (abbreviation: Ir(tppr)2(dpm)), ( Acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]i Ir(Fdpq)2(acac) and other pyrazine-based compounds Organometallic iridium complexes and tris(1-phenylisoquinolinato-N,C 2’ ) Iridium(III) (abbreviation: Ir(piq)3), bis(1-phenylisoquinolinato) -N,C 2’) Iridium(III) acetylacetonate (abbreviation: Ir(piq)2( In addition to organometallic iridium complexes with pyridine skeletons such as acac), 2,3,7, 8,12,13,17,18-Octaethyl-21H,23H-porphyrin platinum(II) ) (abbreviation: PtOEP) and tris(1,3-diphenyl-1,3-propanediol). Eu(DB)(propanedionato)(monophenanthroline)europium(III) M)3(Phen)), tris[1-(2-thenoyl)-3,3,3-trifluoroacetate [Tonato](monophenanthroline)europium(III) (abbreviation: Eu(TTA)3( Among the above, rare earth metal complexes such as pyrimidine skeletons are Organometallic iridium complexes having the above structure are particularly preferred because they are remarkably excellent in reliability and luminous efficiency. In addition, organometallic iridium complexes with a pyrazine skeleton can emit red light with good chromaticity. can be done.

[0121] Among the above-mentioned iridium complexes, organic gold complexes having a pyrimidine skeleton or a pyrazine skeleton are also suitable. In iridium complexes, the ligands have high electron-accepting properties, and the LUMO level tends to be low. This is suitable for one aspect of the present invention. Compounds with electron-withdrawing substituents such as iridium complexes also have LUMO levels This is preferable because the

[0122] The light-emitting material contained in the light-emitting layer 140 is a material capable of converting triplet excitation energy into light. The material capable of converting triplet excitation energy into luminescence is a phosphorescent material. In addition to this, thermally activated delayed fluorescence Therefore, phosphorescent materials are also known as The above-mentioned part may be read as a thermally activated delayed fluorescent material. Delayed fluorescent materials are materials with a small difference between the triplet excitation energy level and the singlet excitation energy level. The function of converting energy from a triplet excited state to a singlet excited state by reverse intersystem crossing. Therefore, the triplet excited state can be converted to the singlet state by a small amount of thermal energy. It is possible to upconvert to an excited state (reverse intersystem crossing) and emit light (fluorescence) from the singlet excited state. ) can be efficiently exhibited. In addition, the conditions for efficiently obtaining thermally activated delayed fluorescence are In this case, the energy difference between the triplet excitation energy level and the singlet excitation energy level is preferably is greater than 0 eV and less than or equal to 0.2 eV, more preferably greater than 0 eV and less than or equal to 0.1 eV The following points can be mentioned.

[0123] When the thermally activated delayed fluorescent material is composed of one kind of material, for example, the following material is used: It is possible.

[0124] First, fullerene and its derivatives, acridine derivatives such as proflavine, and eosin are listed. In addition, magnesium (Mg), zinc (Zn), cadmium (Cd), tin (S n), platinum (Pt), indium (In), or palladium (Pd) Examples of the metal-containing porphyrin include protoporphyrin. Porphyrin-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)), etioporphyrin-tin fluoride complex (SnF2(E tio I)), octaethylporphyrin-platinum chloride complex (PtCl2OEP), etc. It can be obtained.

[0125] In addition, as a thermally activated delayed fluorescent material composed of one kind of material, π-electron-rich heteroaromatic Heterocyclic compounds having an aromatic ring and a π-electron-deficient heteroaromatic ring can also be used. is 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3- a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol {4,6-diphenyl-1,3,5-triazine (PC CzPTzn), 2-[4-(10H-phenoxazin-10-yl)phenyl]-4, 6-Diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5- Phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl PPZ-3TPT, 3-(9,9-dimethyl- 9H-Acridine-10-yl)-9H-xanthen-9-one (Abbreviation: ACRXTN) , bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10'H-spiro[acridine -9,9'-anthracene]-10'-one (abbreviation: ACRSA), etc. The heterocyclic compounds have a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring, Among them, a skeleton having a π-electron-deficient heteroaromatic ring is preferred. Among them, diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton) or triazine skeleton The azine skeleton is preferred because it is stable and reliable. Among the skeletons that have such structures, acridine skeleton, phenoxazine skeleton, thiophene skeleton, and furan skeleton are Since the pyrrole skeleton and the pyrrole skeleton are stable and reliable, any of the skeletons can be used. It is preferable that the pyrrole skeleton has one or more of the following. skeleton, a carbazole skeleton, and 3-(9-phenyl-9H-carbazol-3-yl)- A 9H-carbazole skeleton is particularly preferred. The substance in which the π-electron-rich heteroaromatic ring is directly bonded to the π-electron-deficient heteroaromatic ring exhibits the donor property of the π-electron-rich heteroaromatic ring. The acceptor properties of both heteroaromatic rings are strong, and the levels of the singlet excited state and the triplet excited state are high. This is particularly preferable because the difference in the level is small.

[0126] The light-emitting layer 140 may be composed of two or more layers. When the light-emitting layer 140 is formed by laminating the first light-emitting layer and the second light-emitting layer in this order from the hole transport layer side, a substance having hole transport properties is used as a host material for the first light-emitting layer, and a substance having hole transport properties is used as a host material for the second light-emitting layer In addition, a structure in which a substance having an electron transporting property is used as the first light-emitting layer and the second light-emitting layer is also available. The light-emitting materials in the optical layer and the optical layer may be the same or different materials, and they may emit light of the same color. Even if the material has a function of emitting light, it may have a function of emitting light of different colors. The two light-emitting layers may contain light-emitting materials that emit light of different colors. By using each of these layers, multiple light emissions can be obtained simultaneously. It is preferable to select a light-emitting material for each light-emitting layer so that the resulting light emitted will be white.

[0127] In addition, in the light-emitting layer 140, materials other than the host material 141 and the guest material 142 are It may have.

[0128] The light-emitting layer 140 can be formed by a deposition method (including a vacuum deposition method), an ink-jet method, a coating method, a grating method, or the like. It can be formed by a method such as rabbet printing. In addition to the above-mentioned materials, quantum dots and the like can also be used. Even if the inorganic compound or polymer compound (oligomer, dendrimer, polymer, etc.) good.

[0129] <Hole injection layer> The hole injection layer 111 is formed by injecting holes from one of the pair of electrodes (electrode 101 or electrode 102). It has the function of promoting hole injection by reducing the injection barrier, and is used in materials such as transition metal oxides and fluorine. It is formed by phthalocyanine derivatives or aromatic amines. Examples include molybdenum oxide, vanadium oxide, ruthenium oxide, and tungsten oxide. , manganese oxide, etc. Phthalocyanine derivatives include phthalocyanine, Examples of aromatic amines include benzidine derivatives and phenyl Diamine derivatives, etc. Polymer compounds such as polythiophene and polyaniline Materials such as self-doped polythiophenes, poly(ethylenediamines), can also be used. Typical examples include poly(oxythiophene) / poly(styrenesulfonic acid).

[0130] The hole injection layer 111 is made of a compound material including a hole transporting material and a material that exhibits electron accepting properties. Alternatively, a layer containing a material exhibiting electron accepting properties and a layer containing a material exhibiting electron accepting properties may be used. A stack of layers containing hole transport materials may also be used. It is possible to exchange charges in the presence of a magnetic field. Materials that exhibit electron-accepting properties include quinodimethane. Organic acceptors such as benzophenone derivatives, chloranil derivatives, and hexaazatriphenylene derivatives Specifically, 7,7,8,8-tetracyano-2,3,5,6- Tetrafluoroquinodimethane (abbreviation: F4-TCNQ), chloranil, 2,3,6,7, 10,11-Hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation These compounds have electron-withdrawing groups (halogen groups or cyano groups), such as hydroxybenzoates (HAT-CN). In addition, transition metal oxides, for example, oxides of metals from Groups 4 to 8, can be used. In general, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, These include tungsten oxide, manganese oxide, and rhenium oxide. Among these, it is preferred because it is stable, has low hygroscopicity, and is easy to handle.

[0131] As the hole transporting material, a material having a higher hole transporting property than an electron transporting property can be used. x10 -6 cm 2 It is preferable that the material has a hole mobility of 1 / Vs or more. The aromatic amines and carboxylic acids listed as examples of hole transport materials that can be used in the light-emitting layer 140 are Also usable are benzol derivatives, aromatic hydrocarbons, stilbene derivatives, etc. The hole transporting material may be a polymer compound.

[0132] <Hole transport layer> The hole transport layer 112 is a layer containing a hole transport material. The hole transporting layer 112 can be formed by the hole injection layer 111. Since the hole injection layer 111 has a function of transporting the injected holes to the light emitting layer 140, the highest coverage of the hole injection layer 111 is Highest Occupied Molecular Orbital (H It is preferable that the HOMO level be the same as or close to the OMO level.

[0133] Also, 1×10 -6 cm 2 It is preferable that the material has a hole mobility of 1 / Vs or more. However, other substances may be used as long as they have a higher hole transporting property than electron transporting property. The layer containing a substance with a high hole transporting property may be a single layer or a double layer of the above substance. More than one layer may be laminated.

[0134] ≪Electron transport layer≫ The electron transport layer 118 is connected to the other of the pair of electrodes (electrode 101 or electrode 102) via the electron injection layer 119. The electron transport material has a function of transporting electrons injected from the electrode 102 to the light-emitting layer 140. As the material, a material with higher electron transportability than holes can be used, and the -6 cm 2 It is preferable that the material has an electron mobility of 1 / Vs or more. As materials (materials with electron transport properties), π-electron deficient materials such as nitrogen-containing heteroaromatic compounds are Heteroaromatics and metal complexes can be used. The quinoline ligand, benzoquinoline ligand, and oxalate ligand mentioned above as electron transport materials that can Metal complexes having zole or thiazole ligands, oxadiazole derivatives, Triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzoquinoxaline Sarin derivatives, phenanthroline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidin Examples include amine derivatives and triazine derivatives. -6 cm 2 / Vs or more It is preferable that the material has electron mobility. As long as the electron transport layer 1 is of a suitable quality, other materials may be used as the electron transport layer. 18 may be not only a single layer, but also a laminate of two or more layers made of the above materials.

[0135] In addition, a layer for controlling the movement of electron carriers is provided between the electron transport layer 118 and the light emitting layer 140. The layer for controlling the movement of electron carriers may be made of a material having high electron transport properties as described above. A layer in which a small amount of a substance with high electron trapping properties is added to the By doing so, it becomes possible to adjust the carrier balance. Suppression of problems caused by electrons penetrating the optical layer (such as reduced device lifespan) has a great effect on.

[0136] ≪Electron injection layer≫ The electron injection layer 119 promotes electron injection by reducing the electron injection barrier from the electrode 102. For example, Group 1 metals, Group 2 metals, or their oxides and halides In addition, the electron transport material and the corresponding electron transport material can be used. A composite material of a material exhibiting electron donating properties can also be used. Examples include Group 1 metals, Group 2 metals, and oxides thereof. are lithium fluoride (LiF), sodium fluoride (NaF), and cesium fluoride (CsF ), calcium fluoride (CaF2), lithium oxide (LiO x) and other alkaline gold Metals, alkaline earth metals, or compounds thereof can be used. A rare earth metal compound such as erbium (ErF3) can be used. An electride may be used for 119. The electride may be, for example, calcium. Examples include a material in which electrons are highly concentrated in a mixed oxide of aluminum and silicon. The injection layer 119 may be made of a material that can be used in the electron transport layer 118 .

[0137] The electron injection layer 119 may contain a composite material formed by mixing an organic compound and an electron donor (donor). Such composite materials may be formed by electron donors giving electrons to organic compounds. In this case, the organic compound is It is preferable that the material is excellent in transporting the generated electrons. Specifically, for example, the above-mentioned The material constituting the electron transport layer 118 (metal complex, heteroaromatic compound, etc.) can be used. The electron donor may be any substance that exhibits electron donating properties to organic compounds. For the metal, alkali metals, alkaline earth metals and rare earth metals are preferred, and lithium, sodium , cesium, magnesium, calcium, erbium, ytterbium, etc. In addition, alkali metal oxides and alkaline earth metal oxides are preferred, and lithium oxide, calcium oxide, Examples of oxides include sodium oxide and barium oxide. Lewis oxides such as magnesium oxide are also included. A base can also be used. In addition, organic compounds such as tetrathiafulvalene (TTF) can be used. You can also use objects.

[0138] The above-mentioned light-emitting layer, hole-injection layer, hole-transport layer, electron-transport layer, and electron-injection layer are These methods include vapor deposition (including vacuum deposition), inkjet printing, coating, and gravure printing. The light-emitting layer, the hole-injecting layer, the hole-transporting layer, the electron In addition to the materials mentioned above, inorganic compounds such as quantum dots and high molecular weight compounds can be used for the transport layer and electron injection layer. A polymer compound (oligomer, dendrimer, polymer, etc.) may also be used.

[0139] Quantum dots include colloidal quantum dots, alloy quantum dots, and core-shell quantum dots. It is also possible to use quantum dots of the 2nd group and the 16th group, quantum dots of the 13th group, and the like. Contains element groups from group 15, 13 and 17, 11 and 17, or 14 and 15 Quantum dots may also be used. Alternatively, cadmium (Cd), selenium (Se), zinc (Zn ), sulfur (S), phosphorus (P), indium (In), tellurium (Te), lead (Pb), gallium Quantum dots containing elements such as Ga, As, and Al are used. It's fine.

[0140] <Pair of electrodes> The electrode 101 and the electrode 102 function as an anode or a cathode of the light-emitting element. The electrode 101 and the electrode 102 may be made of a metal, an alloy, a conductive compound, or a mixture or laminate thereof. It can be formed using, for example.

[0141] One of the electrodes 101 and 102 is made of a conductive material that has a function of reflecting light. The conductive material is preferably aluminum (Al) or a compound containing Al. Examples of alloys containing Al include Al and L (L is titanium (Ti), neodymium (Ne), etc. (representing one or more of Nd, Ni, and La) Examples of suitable alloys include alloys containing Al and Ti, or alloys containing Al, Ni and La. Aluminum has low resistance and high light reflectivity. Since aluminum is abundant and inexpensive, the cost of manufacturing a light-emitting element using aluminum is reduced. In addition, silver (Ag) or Ag and N (N) can be used in combination with yttrium ( Y), Nd, magnesium (Mg), ytterbium (Yb), Al, Ti, gallium ( Ga), zinc (Zn), indium (In), tungsten (W), manganese (Mn), Tin (Sn), iron (Fe), Ni, copper (Cu), palladium (Pd), iridium (Ir ), or an alloy containing gold (Au), etc. Examples of alloys containing silver 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, silver and ytterbium Other examples include alloys containing tungsten, chromium (Cr), molybdenum (Mo ), copper, titanium, and other transition metals can be used.

[0142] The light emitted from the light-emitting layer is emitted through one or both of the electrodes 101 and 102. Therefore, at least one of the electrodes 101 and 102 is transparent to light. It is preferable that the conductive material is made of a conductive material having a function of transmitting visible light. The light transmittance is 40% or more and 100% or less, preferably 60% or more and 100% or less, and Its resistivity is 1×10 -2 Examples include conductive materials with a resistance of Ω·cm or less.

[0143] The electrodes 101 and 102 have a function of transmitting light and a function of reflecting light. The conductive material may be formed of a conductive material having a visible light reflectance of 20 or less. % or more and 80% or less, preferably 40% or more and 70% or less, and the resistivity is 1×10 -2 Conductive materials with a resistance of Ω·cm or less include metals, alloys, and conductive materials. The layer can be formed by using one or more of the following compounds. Indium Tin Oxide (ITO), silicon or silicon oxide Indium tin oxide (ITSO), indium oxide-zinc oxide (Indi Indium tin oxide containing titanium, indium tin oxide, Metals such as indium oxide containing titanium oxide, tungsten oxide, and zinc oxide Oxides can be used. In addition, the thickness of the oxide is preferably within a range of 1 nm to 30 nm. A metal thin film having a thickness of 1 μm or less can be used. Examples of metals include Ag, Alloys such as Ag and Al, Ag and Mg, Ag and Au, and Ag and Yb can be used.

[0144] In this specification and the like, a material having a function of transmitting light refers to a material having a function of transmitting visible light. Any material having the above and having electrical conductivity may be used, and examples thereof include ITO. In addition to oxide conductors, oxide semiconductors or organic conductors containing organic materials are also included. The organic conductor may be, for example, a mixture of an organic compound and an electron donor. Examples of such materials include composite materials, and composite materials made by mixing organic compounds and electron acceptors. Alternatively, inorganic carbon materials such as graphene may be used. The ratio is preferably 1×10 5 Ω·cm or less, more preferably 1×10 4 Ω cm The following is the result.

[0145] In addition, by laminating a plurality of the above materials, one or both of the electrodes 101 and 102 can be formed. may form both.

[0146] In order to improve the light extraction efficiency, the electrode is in contact with the light-transmitting electrode. A material having a higher refractive index than the electrode may be used. Any material that has the function of providing the desired electrical conductivity may be used. For example, in addition to the oxide conductors described above, oxide semiconductors and organic materials can be used. The organic material may be, for example, a light-emitting layer, a hole injection layer, a hole transport layer, an electron transport layer, or an electron transport layer. The materials exemplified for the electron injection layer are also usable. Inorganic carbon materials and thin films that are light-transmitting are also usable. These high refractive index materials can be used to form thin films with a size of several nanometers to several tens of nanometers. A plurality of layers may be laminated.

[0147] When the electrode 101 or the electrode 102 functions as a cathode, the work function is small. (3.8 eV or less) materials. For example, materials in Group 1 or 2 of the Periodic Table of Elements. Elements belonging to the group (alkali metals such as lithium, sodium, and cesium, calcium, strontium, etc.) Alkaline earth metals such as rontium, magnesium, etc.), alloys containing these elements (e.g., Rare earth metals such as Ag and Mg, Al and Li), europium (Eu), Yb, etc. An alloy containing a metal, such as an alloy containing aluminum or silver, can be used.

[0148] Furthermore, when the electrode 101 or the electrode 102 is used as an anode, a material having a large work function (4. It is preferable to use a material having a refractive index of 0 eV or more.

[0149] The electrodes 101 and 102 are made of a conductive material that reflects light and a light-transmitting material. In this case, the electrode 101 and the electrode 102 may be laminated with a conductive material having a permeability function. 02 resonates the desired light from each light-emitting layer, allowing the light of that wavelength to be intensified. This is preferable because it can have the function of adjusting the optical distance.

[0150] The electrode 101 and the electrode 102 can be formed by a sputtering method, a vapor deposition method, a printing method, or a coating method. , MBE (Molecular Beam Epitaxy) method, CVD method, pulse laser The deposition method, ALD (Atomic Layer Deposition) method, etc. are used appropriately. It is possible.

[0151] <Substrate> Furthermore, the light-emitting element according to one embodiment of the present invention may be formed on a substrate made of glass, plastic, or the like. As for the order of fabrication on the substrate, the layers may be stacked in order from the electrode 101 side. They may be stacked in order from the pole 102 side.

[0152] The substrate on which the light-emitting element according to one embodiment of the present invention can be formed is, for example, glass or quartz. Alternatively, a flexible substrate may be used. The substrate is a flexible substrate, such as polycarbonate. Examples of suitable substrates include plastic substrates made of vinyl acetate and polyarylate. Inorganic vapor deposition films can also be used. Any other material may be used as long as it functions as a support in the development. Anything that has the function of protecting the optical element and the optical device may be used.

[0153] For example, in the present invention, a light emitting element can be formed using various substrates. The type of substrate is not particularly limited. An example of the substrate is a semiconductor substrate (e.g., a single crystal substrate or silicon substrate), SOI substrate, glass substrate, quartz substrate, plastic substrate, metal Substrate, stainless steel substrate, substrate with stainless steel foil, tungsten substrate, tungsten foil substrate, flexible substrate, laminated film, fibrous Examples of glass substrates include paper or substrate films containing barium phosphate. Examples include borosilicate glass, aluminoborosilicate glass, and soda-lime glass. Examples of the functional substrate, laminate film, base film, etc. are as follows: For example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), Representative examples include polyethersulfone (PES) and polytetrafluoroethylene (PTFE). For example, there is a plastic material such as acrylic resin. Examples include polypropylene, polyester, polyvinyl fluoride, or polyvinyl chloride. Examples include polyamide, polyimide, aramid, epoxy, and inorganic. Examples include metallized films and papers.

[0154] Alternatively, a flexible substrate may be used as the substrate, and the light emitting element may be formed directly on the flexible substrate. Alternatively, a release layer may be provided between the substrate and the light-emitting element. After a part or all of a device is completed, it is separated from the substrate and used to transfer it to another substrate. In this case, the light-emitting element can be transferred onto a substrate having poor heat resistance or a flexible substrate. The peeling layer may have a laminated structure of inorganic films, such as a tungsten film and a silicon oxide film. or a structure in which a resin film such as polyimide is formed on a substrate, etc., can be used.

[0155] That is, a light emitting element is formed using a certain substrate, and then the light emitting element is transferred to another substrate. The light emitting element may be disposed on another substrate. In addition to the substrates mentioned above, cellophane substrates, stone substrates, wood substrates, fabric substrates (natural fibers (silk, cotton, Hemp), synthetic fibers (nylon, polyurethane, polyester) or regenerated fibers (acetate (including cellulose, cupro, rayon, recycled polyester, etc.), leather substrate, rubber substrate, etc. By using these substrates, it is possible to produce light emitting elements that are durable and highly heat resistant. The light emitting element may be a small, lightweight, or thin light emitting element.

[0156] Furthermore, for example, a field effect transistor (FET) is formed on the above-mentioned substrate, and the FET and The light emitting element 152 may be fabricated on the electrically connected electrodes. In this way, an active matrix display device that controls the driving of the light emitting element 152 can be manufactured.

[0157] Note that one embodiment of the present invention has been described in this embodiment. However, the present invention is not limited to these embodiments. That is, various inventive aspects are described in this and other embodiments. Therefore, one embodiment of the present invention is not limited to a specific embodiment. However, one embodiment of the present invention is not limited to this. For example, in some cases or depending on the situation, one embodiment of the present invention may be applied to a light-emitting element. Alternatively, for example, in one embodiment of the present invention, a first organic compound and a second organic compound may be used. An organic compound and a guest molecule capable of converting triplet excitation energy into luminescence a material, wherein the LUMO level of the first organic compound is higher than the LUMO level of the second organic compound; The HOMO level of the first organic compound is lower than the HOMO level of the second organic compound. However, one embodiment of the present invention is not limited to this. In one embodiment of the present invention, depending on the situation, for example, the LUMO level of the first organic compound is The LUMO level of the first organic compound may not be lower than that of the second organic compound. The HOMO level does not have to be lower than the HOMO level of the second organic compound. For example, in one embodiment of the present invention, a first organic compound and a second organic compound form an exciplex. However, one embodiment of the present invention is not limited to this. In one embodiment of the present invention, for example, a first organic compound and a second organic compound Alternatively, for example, in one embodiment of the present invention, the guest material may not form an exciplex. The LUMO level of the first organic compound is lower than the LUMO level of the guest material. Although the level is lower than the HOMO level of the second organic compound, one embodiment of the present invention However, in some cases or depending on the situation, in one aspect of the present invention, For example, the LUMO level of the guest material is not lower than the LUMO level of the first organic compound. Alternatively, the HOMO level of the guest material may be higher than the HOMO level of the second organic compound. It does not have to be lower.

[0158] As described above, the structure shown in this embodiment mode can be used in appropriate combination with other embodiment modes. Cut.

[0159] (Embodiment 2) In this embodiment mode, a light-emitting element having a different structure from that of the light-emitting element shown in Embodiment 1 is This will be explained below with reference to Figs. 3 and 4. The parts with the same function as the symbols shown in (A) are given the same hatch pattern and the symbols are omitted. In addition, parts having similar functions are given similar reference numerals, and their details are omitted. The explanation may be omitted.

[0160] <Configuration example 1 of light-emitting element> FIG. 3A is a schematic cross-sectional view of the light emitting element 250. As shown in FIG.

[0161] The light-emitting element 250 shown in FIG. 3A has a pair of electrodes (electrodes 101 and 102) between them. , a plurality of light-emitting units (in FIG. 3A, light-emitting unit 106 and light-emitting unit 1 08). Any one of the plurality of light-emitting units has the light-emitting unit shown in FIG. It is preferable that the light-emitting element 152 has a structure similar to that of the EL layer 100. That is, the light-emitting element 152 shown in FIG. , preferably has one light-emitting unit, and the light-emitting element 250 preferably has multiple light-emitting units. In the light-emitting element 250, the electrode 101 functions as an anode, and the electrode 102 functions as a cathode. However, the configuration of the light emitting element 250 may be reversed. It's okay.

[0162] In addition, in the light-emitting element 250 shown in FIG. 3(A), the light-emitting unit 106 and the light-emitting unit The light-emitting units 106 and 108 are stacked, and a charge generating layer is formed between the light-emitting units 106 and 108. The light-emitting unit 106 and the light-emitting unit 108 have the same structure. For example, the light-emitting unit 108 may have the EL layer 100 shown in FIG. It is preferable to have one.

[0163] The light emitting element 250 has a light emitting layer 120 and a light emitting layer 170. In addition to the light-emitting layer 120, the knit 106 includes a hole injection layer 111, a hole transport layer 112, an electron transport layer The light-emitting unit 108 also includes an emissive layer 170. In addition to the above, a hole injection layer 116, a hole transport layer 117, an electron transport layer 118, and an electron injection layer 11 It has 9.

[0164] The charge generation layer 115 is formed by adding an acceptor material, which is an electron acceptor, to a hole transport material. Even if the electron transport material is an electron donor, a donor material may be added to the electron transport material. Alternatively, both of these structures may be stacked.

[0165] When the charge generation layer 115 contains a composite material of an organic compound and an acceptor substance, the The composite material that can be used for the hole-injection layer 111 shown in Embodiment 1 is used as the composite material. The organic compounds include aromatic amine compounds, carbazole compounds, aromatic carbonized compounds, and the like. Various compounds such as hydrogen and polymer compounds (oligomers, dendrimers, polymers, etc.) are used. As for organic compounds, those with a hole mobility of 1×10 -6 cm 2 / Vs However, if a material has a higher hole transporting property than an electron transporting property, it is preferable that the above-mentioned Other materials may also be used. A composite material of an organic compound and an acceptor material is suitable for carrier injection. Because of its excellent conductivity and carrier transport properties, low voltage and low current operation can be achieved. As in the light-emitting unit 108, the surface of the light-emitting unit on the anode side is connected to the charge generating layer 115. When the charge generating layer 115 is in contact with the hole injection layer or hole transport layer of the light emitting unit, Since the light-emitting unit can also play a role of a hole injection layer or a hole transport layer, the light-emitting unit does not need to be provided with a hole injection layer or a hole transport layer. It may have a different configuration.

[0166] The charge generation layer 115 may be a layer containing a composite material of an organic compound and an acceptor substance, or another layer containing a compound of an organic compound and an acceptor substance. For example, the organic EL element may be formed as a laminated structure in which layers made of the organic EL element are combined. A layer including a composite material of a compound and an acceptor substance and a layer including a compound selected from electron donor substances. The compound may be formed by combining a layer containing the compound with a compound having a high electron transporting property. A layer containing a composite material of an organic compound and an acceptor substance and a layer containing a transparent conductive film are combined. It may be formed by combining the above.

[0167] The charge generating layer 115 sandwiched between the light emitting unit 106 and the light emitting unit 108 When a voltage is applied between the electrode 101 and the electrode 102, electrons are injected into one of the light-emitting units, It is sufficient if it injects holes into the other light-emitting unit. For example, in FIG. 3(A), When a voltage is applied so that the potential of electrode 101 is higher than the potential of electrode 102, The charge generating layer 115 injects electrons into the light-emitting unit 106 and holes into the light-emitting unit 108. Enter.

[0168] From the viewpoint of light extraction efficiency, the charge generation layer 115 is transparent to visible light (specifically, It is preferable that the charge generating layer 115 has a visible light transmittance of 40% or more. The charge generating layer 115 has a lower conductivity than the pair of electrodes (electrodes 101 and 102). It still works.

[0169] By forming the charge generating layer 115 using the above-mentioned materials, when a light emitting layer is laminated, In this case, the increase in the driving voltage can be suppressed.

[0170] In addition, in FIG. 3A, a light-emitting element having two light-emitting units has been described. However, it can also be applied to light-emitting devices in which three or more light-emitting units are stacked. As shown in the light-emitting element 250, a plurality of light-emitting units are disposed between a pair of electrodes, and a charge generating layer is formed. By separating the layers, high brightness light emission is possible while keeping the current density low. A light-emitting element with a long life and low power consumption can be realized. .

[0171] At least one of the multiple units has the structure shown in the first embodiment. By applying this composition, a light-emitting element with high luminous efficiency can be provided.

[0172] The light-emitting layer 170 of the light-emitting unit 108 is the same as the light-emitting layer 14 shown in the first embodiment. It is preferable that the light-emitting layer 170 has the same structure as the light-emitting layer 140 shown in the first embodiment. By having a similar structure, the light-emitting element 250 has a phosphorescent material as a light-emitting material, and This is preferable as it becomes a light emitting element with high luminous efficiency.

[0173] The light-emitting layer 120 of the light-emitting unit 106 is formed of a host The material 121 and the guest material 122 are fluorescent materials. , as explained below.

[0174] <Light Emitting Mechanism of Light Emitting Layer 120> The light emitting mechanism of the light emitting layer 120 will be explained below.

[0175] Electrons injected from a pair of electrodes (electrodes 101 and 102) or a charge generating layer and The recombination of the guest material 1 and the electron hole in the light-emitting layer 120 generates an exciton. Since the host material 121 is present in a large amount compared to 22, the generation of excitons An excited state of the material 121 is formed.

[0176] An exciton is a pair of carriers (electrons and holes). Therefore, the material in which the excitons are generated is in an excited state.

[0177] When the excited state of the formed host material 121 is a singlet excited state, the host material 12 Singlet excitation energy is transferred from the S1 level of 1 to the S1 level of the guest material 122. As a result, the singlet excited state of the guest material 122 is formed.

[0178] Since the guest material 122 is a fluorescent material, the singlet excited state is Once formed, the guest material 122 emits light quickly. For this purpose, it is preferable that the guest material 122 has a high fluorescence quantum yield. In 2, the same applies when carriers recombine and the resulting excited state is a singlet excited state. is.

[0179] Next, when carrier recombination forms a triplet excited state in the host material 121, In this case, the energy levels of the host material 121 and the guest material 122 are The correlation between the positions is shown in Figure 3(C). The notations and symbols in Figure 3(C) are as follows: The T1 level of the host material 121 is lower than the T1 level of the guest material 122. This is preferable, and therefore, in FIG. 3C, this case is illustrated. may be higher than the T1 level of the guest material 122.

[0180] Host (121): Host material 121 Guest (122): Guest material 122 (fluorescent material) ·S FH : S1 level of the host material 121 T FH : T1 level of the host material 121 ·S FG : S1 level of guest material 122 (fluorescent material) T FG : T1 level of guest material 122 (fluorescent material)

[0181] As shown in Figure 3(C), triplet-triplet annihilation (TTA) Triplets generated by carrier recombination (by Excitons interact with each other, transferring excitation energy and exchanging spin angular momentum. As a result, the S1 level (S FH ) with energy A reaction occurs in which the ions are converted into doublet excitons (see TTA in Figure 3(C)). The singlet excitation energy is S FH From the lower energy guest material 122 S1 level (S FG ) (see route E1 in Figure 3(C)), and the guest material A singlet excited state of the guest material 122 is formed, and the guest material 122 emits light.

[0182] When the density of triplet excitons in the light-emitting layer 120 is sufficiently high (for example, 1×10 -12 cm -3 In the above, the deactivation of a single triplet exciton is ignored, and the deactivation of two adjacent triplet excitons is considered. Only reactions due to triggers can be considered.

[0183] Furthermore, when carriers recombine in the guest material 122 to form a triplet excited state, The energy of the triplet excited state of the guest material 122 can be utilized for light emission because it is thermally deactivated. However, the T1 level (T FH ) is guest material 1 22 T1 levels (T FG ), the triplet excitation energy of the guest material 122 is T1 level (T FG ) to the T1 level (T FH )Hehe It is possible to transfer energy (see route E2 in Figure 3(C)) and then utilize it for TTA. It is used.

[0184] That is, the host material 121 converts triplet excitation energy into singlet excitation energy by TTA. It is preferable that the light-emitting layer 120 has a function of converting the generated light into energy. A portion of the triplet excitation energy is converted to singlet excitation energy by TTA in the host material 121. The singlet excitation energy is converted into the guest material 122, and the guest material 122 is transferred to the guest material 122, thereby producing fluorescence. To achieve this, the S1 level (S FH ) is the S1 level (S FG ) is preferable. T1 level (T FH ) is the T1 level (T FG ) lower It is preferable.

[0185] In particular, the T1 level (T FG ) is the T1 level (T FH ), the weight ratio of the host material 121 to the guest material 122 is It is preferable that the weight ratio of the guest material 122 is low. The weight ratio of the guest material 122 to the hydroxyl group is preferably greater than 0 and equal to or less than 0.05. By setting the amount ratio relationship, the probability of carrier recombination in the guest material 122 can be reduced. In addition, the T1 level (T FH ) from guest material 122 T1 Level (T FG ) can reduce the probability of energy transfer to

[0186] The host material 121 may be composed of a single compound or a plurality of compounds. It may be formed.

[0187] In each of the above configurations, the gates used in the light-emitting units 106 and 108 The light-emitting materials may emit the same or different colors. In the case where the light-emitting unit 106 and the light-emitting unit 108 have guest materials that have the function of emitting light of the same color, In this case, the light emitting element 250 is preferable as it exhibits high light emitting brightness with a small current value. In addition, the light-emitting units 106 and 108 have the function of emitting light of different colors. When the light-emitting element 250 contains a guest material having the above-mentioned structure, the light-emitting element 250 becomes a light-emitting element that exhibits multicolor emission, which is preferable. In this case, it is preferable to provide a light emitting layer 120 or a light emitting layer 170 having an emission wavelength of 1000 nm or more. By using different light-emitting materials, the light-emitting element 250 exhibits an emission spectrum of Since the light emitted from the source has different emission peaks, it has at least two maxima. The resulting emission spectrum is

[0188] The above-mentioned configuration is also suitable for obtaining white light emission. By making the colors complementary to each other, white light can be emitted. The guest is then reacted with the guest to produce a highly white luminescent compound, or at least a luminescent compound having red, green, and blue components. It is preferable to select the material.

[0189] In addition, either or both of the light-emitting layer 120 and the light-emitting layer 170 may be further divided into layers. Each of the divided layers may contain a different light-emitting material. Either or both of the layer 120 and the light-emitting layer 170 are composed of two or more layers. For example, the first light-emitting layer and the second light-emitting layer may be stacked in this order from the hole transport layer side. When the light-emitting layer is formed by using a material having a hole-transporting property as a host material of the first light-emitting layer, For example, a substance having an electron transporting property is used as a host material for the second light-emitting layer. In this case, the light-emitting materials of the first light-emitting layer and the second light-emitting layer may be different materials even if they are the same material. Even if the material has the function of emitting light of the same color, it may emit light of different colors. The materials may be materials that have the function of emitting light of different colors. The structure of the LEDs is made up of multiple light-emitting materials, and they emit three primary colors or four or more colors with high color rendering. White light emission can also be obtained.

[0190] In addition, the light-emitting units 106 and 108 have guest materials with different emission colors. In this case, the emission from the light-emitting layer 120 has a peak in the shorter wavelength side than the emission from the light-emitting layer 170. It is preferable to use a material having a high triplet excitation energy level. The light-emitting element used in this method tends to have a tendency to deteriorate quickly in brightness. By using TA, it is possible to provide a light-emitting element with little deterioration in luminance.

[0191] <Configuration example 2 of light-emitting element> Next, regarding a configuration example different from that of the light-emitting element shown in FIG. 3, we will use FIGS. 4(A), (B), and (C) to explain the configuration example. The following explanation will be given.

[0192] FIG. 4A is a schematic cross-sectional view of the light emitting element 252. FIG.

[0193] The light-emitting element 252 shown in FIG. 4A has a pair of electrodes (electrodes 101 and 102) between them. The EL layer 110 is sandwiched between the electrodes 101 and 102. The following description will be given assuming that the electrode 101 functions as a cathode and the electrode 102 functions as a cathode. 2 The configuration may be reversed.

[0194] The EL layer 110 also includes a light-emitting layer 180, which is a light-emitting layer 120 and a light-emitting layer 130. In the light-emitting element 252, the EL layer 110 includes a light-emitting layer In addition, a hole injection layer 111, a hole transport layer 112, an electron transport layer 118, and an electron injection layer 119 However, these laminated structures are merely examples, and the EL layer 1 in the light-emitting element 252 The configuration of the EL layer 110 is not limited to these. For example, the stacking order of the above layers in the EL layer 110 is Alternatively, the EL layer 110 may be provided with a functional layer other than the above layers. The functional layer may have a function of reducing the hole or electron injection barrier, a function of reducing the hole or electron injection barrier, or a function of reducing the hole or electron injection barrier. The function of improving the transportability of electrons, the function of inhibiting the transportability of holes or electrons, The configuration may have a function of generating the signal.

[0195] As shown in FIG. 4B, the light-emitting layer 120 is made of a host material 121 and a guest material 122. The light-emitting layer 170 contains a host material 171 and a guest material 172. The host material 171 includes an organic compound 171_1 and an organic compound 171_2. In the following description, the guest material 122 is a fluorescent material and the guest material 172 is a phosphorescent material. do.

[0196] <Light-emitting mechanism of the light-emitting layer 180> The light emitting mechanism of the light emitting layer 120 is the same as that of the light emitting layer 120 shown in FIG. The light-emitting mechanism of the light-emitting layer 170 is the same as that of the light-emitting layer 140 shown in the first embodiment. The mechanism is as follows: host material 171, organic compound 171_1, organic compound 171_ 2, and the guest material 172 are the host material 141, the guest material 142, and the organic compound 141. _1 and organic compound 141_2, respectively.

[0197] As shown in the light emitting element 252, the light emitting layer 120 and the light emitting layer 170 are in contact with each other. In this case, the exciplex of the light-emitting layer 120 is converted into the exciplex of the light-emitting layer 170 at the interface between the light-emitting layer 120 and the light-emitting layer 170. Energy transfer (especially energy transfer of triplet excited levels) to the host material 121 occurs. Even if the triplet excitation energy is not converted into light emission in the light-emitting layer 120, do.

[0198] The T1 level of the host material 121 of the light-emitting layer 120 is higher than that of the organic compound contained in the light-emitting layer 170. It is preferable that the T1 level of the light-emitting layer is lower than the T1 level of the organic compound 171_1 and the organic compound 171_2. In 120, the S1 level of the host material 121 is higher than the S1 level of the guest material 122 (fluorescent material). The T1 level of the host material 121 is higher than the T1 level of the guest material 122 (fluorescent material). It is preferable that the level is lower than 1.

[0199] Specifically, when TTA is used for the light-emitting layer 120 and ExTET is used for the light-emitting layer 170, The correlation of the energy levels is shown in Figure 4(C). The notations and symbols in Figure 4(C) are as follows: It is as follows. Fluorescence EML(120): Emitting layer 120 (fluorescent emitting layer) Phosphorescence EML(170): Emitting layer 170 (phosphorescent emitting layer) Host (121): Host material 121 Guest (122): Guest material 122 (fluorescent material) ·Host(171_1): Host material (organic compound 171_1) Guest (172): Guest material 172 (phosphorescent material) ·Exciplex: Excitation complex (organic compound 171_1 and organic compound 171_2) ·S FH : S1 level of the host material 121 T FH : T1 level of the host material 121 ·S FG : S1 level of guest material 122 (fluorescent material) T FG : T1 level of guest material 122 (fluorescent material) ·S PH : S1 level of the host material (organic compound 171_1) T PH : T1 level of the host material (organic compound 171_1) T PG: T1 level of guest material 172 (phosphorescent material) ·S E : S1 level of the exciplex T E :T1 level of exciplex

[0200] As shown in Figure 4(C), exciplexes exist only in the excited state, so The exciton diffusion between the exciplex and the nucleus is difficult. E , T E ) is the excitation light of the organic compound 171_1 of the light-emitting layer 170 (i.e., the host material of the phosphorescent material). Electron energy level (S PH , T PH ) is lower than that of the exciplex, so the In other words, in the phosphorescent light-emitting layer (light-emitting layer 170), Since the exciton diffusion distance of the exciplex is short, the efficiency of the phosphorescent light-emitting layer (light-emitting layer 170) can be maintained. In addition, the interface between the fluorescent light-emitting layer (light-emitting layer 120) and the phosphorescent light-emitting layer (light-emitting layer 170) In the phosphorescent light-emitting layer (light-emitting layer 170), part of the triplet excitation energy of the exciplex is converted into a fluorescent Even if the light-emitting layer (light-emitting layer 120) is diffused, the fluorescent light-emitting layer (light-emitting layer 120) generated by the diffusion The triplet excitation energy of the photoluminescent layer 120 is converted into light emission through TTA. It is possible to reduce energy loss.

[0201] As described above, the light-emitting device 252 uses ExTET for the light-emitting layer 170 and By using TTA in 20, energy loss is reduced, resulting in high luminous efficiency. As shown in the light-emitting element 252, the light-emitting layer 120 and the light-emitting layer 170 are in contact with each other, the energy loss is reduced and E The number of L layers 110 can be reduced. Therefore, the light emitting device can be manufactured at low cost. It can be said that:

[0202] The light-emitting layer 120 and the light-emitting layer 170 may not be in contact with each other. In this case, the organic compound 171_1, the organic compound 171_2, or The guest material 172 (phosphorescent material) is excited into the host material 121 in the light-emitting layer 120. Energy transfer via the Dexter mechanism to the guest material 122 (fluorescent material) (especially triple Therefore, the energy transfer between the light-emitting layer 120 and the light-emitting layer 170 can be prevented. The layer provided between them only needs to be a few nm thick. Specifically, it should be between 1 nm and 5 nm. This is preferable because it is possible to suppress an increase in the driving voltage.

[0203] The layer provided between the light-emitting layer 120 and the light-emitting layer 170 may be made of a single material. The layer may contain both a hole transporting material and an electron transporting material. In this case, a bipolar material may be used. The ratio of the mobility of a hole transport material to that of an electron transport material is 100 or less. Alternatively, at least one of them may be a host material for the light-emitting layer 170. Even if it is formed from the same material as the substrate material (organic compound 171_1 or organic compound 171_2), This makes it easier to fabricate the light-emitting device and reduces the driving voltage. The hole transporting material and the electron transporting material may form an exciplex, which generates an exciton Specifically, the host material (organic compound) of the light-emitting layer 170 can be effectively prevented from diffusing. Excitation of organic compounds (171_1 or 171_2) or guest materials (phosphorescent materials) From the excited state to the host material 121 or guest material 122 (fluorescent material) of the light-emitting layer 120 This can prevent the transfer of energy.

[0204] In the light-emitting element 252, the light-emitting layer 120 is on the hole transport layer 112 side, and the light-emitting layer 170 is on the hole transport layer 112 side. However, the light-emitting element of one embodiment of the present invention is not limited to this. The light-emitting layer 120 is on the electron transport layer 118 side, and the light-emitting layer 170 is on the hole transport layer 112 side. It's okay.

[0205] In the light emitting element 252, the recombination region of the carriers is formed with a certain degree of distribution. Therefore, it is preferable that the light-emitting layer 120 or the light-emitting layer 170 has an appropriate carrier. It is preferable that the guest material 172 (phosphorus) contained in the light-emitting layer 170 has an attrapping property. Therefore, it is preferable that the light-emitting layer 170 has an electron trapping property. Therefore, the configuration of the light-emitting layer 140 shown in the first embodiment is preferable.

[0206] The light emitted from the light-emitting layer 120 has a peak at a shorter wavelength than the light emitted from the light-emitting layer 170. It is preferable that the light-emitting element has a structure including a phosphorescent material that emits light of a short wavelength. Therefore, by using fluorescent light for short wavelengths, A light-emitting element with little deterioration in luminance can be provided.

[0207] Furthermore, by obtaining light of different wavelengths from the light-emitting layer 120 and the light-emitting layer 170, multicolor The light-emitting element may have different emission peaks in the emission spectrum. Since the emitted light is synthesized, the emission spectrum has at least two maxima. .

[0208] The above structure is also suitable for obtaining white light emission. By making the light from the two fluorescent materials complementary to each other, white light can be emitted.

[0209] In addition, one or both of the light-emitting layer 120 and the light-emitting layer 170 may have different emission wavelengths. By using multiple luminescent materials, it is possible to produce high color rendering with three primary colors or four or more luminescent colors. In this case, the light-emitting layer is further divided into layers, and the divided layers are Each layer may contain a different light-emitting material.

[0210] <Examples of materials that can be used for the light-emitting layer> Next, materials that can be used for the light-emitting layer 120 and the light-emitting layer 170 will be described below. do.

[0211] <Materials that can be used for the light-emitting layer 120> In the light-emitting layer 120, the host material 121 is present in the largest amount by weight, and the guest material 122 The fluorescent material is dispersed in the host material 121. The S1 level of the host material 121 is The S1 level of the host material 121 is higher than the S1 level of the fluorescent material 122. It is preferable that the T1 level is lower than the T1 level of the source material 122 (fluorescent material).

[0212] In the light-emitting layer 120, the guest material 122 is not particularly limited, but may be anthracene. derivatives, tetracene derivatives, chrysene derivatives, phenanthrene derivatives, pyrene derivatives, Rylene derivatives, stilbene derivatives, acridone derivatives, coumarin derivatives, phenoxazine Derivatives, phenothiazine derivatives, etc. are preferred, and for example, the following materials can be used: .

[0213] Specifically, 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2 ,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl -9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2 BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoro (9-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-di Amine (abbreviation: 1,6tBu-FLPAPrn), N,N'-diphenyl-N,N'-biphenyl bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-3,8-dicyclo[4-(9-phenyl-9H-fluoren-9-yl)phenyl] Hexylpyrene-1,6-diamine (abbreviation: ch-1,6FLPAPrn), N,N'- Bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstil Ben-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl )-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA ), 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-an tolyl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4 -(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine( Abbreviation: PCAPA), Perylene, 2,5,8,11-tetra(tert-butyl)perylene TBP, 4-(10-phenyl-9-anthryl)-4'-(9-phenyl -9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), N,N ''-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene ) Bis[N,N',N'-triphenyl-1,4-phenylenediamine] (abbreviation: DPA BPA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl) phenyl]-9H-carbazol-3-amine (abbreviation: 2PCAPPA), N-[4-( 9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl- 1,4-Phenylenediamine (abbreviation: 2DPAPPA), N,N,N',N',N'', N'',N''',N'''-Octaphenyldibenzo[g,p]chrysene-2,7,1 0,15-tetraamine (abbreviation: DBC1), Coumarin 30, N-(9,10-diphenyl (2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-an [Tolyl]-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABP hA), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl Di-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-carbazol-9-yl)phenyl]-N- Phenylanthracene-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenyl Nylanthracene-9-amine (abbreviation: DPhAPhA), Coumarin 6, Coumarin 545 T, N,N'-diphenylquinacridone (abbreviation: DPQd), rubrene, 2,8-di-t ert-butyl-5,11-bis(4-tert-butylphenyl)-6,12-diphenyl Nyltetracene (abbreviation: TBRb), Nile Red, 5,12-bis(1,1'-biphenyl) 2-( ... -[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-yl 2-(2-methyl-6-[(2-(2, 3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl N,N-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N',N'-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation :p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methylphenyl) acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: p-mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl 2,3,6,7-Tetrahydro-1H,5H-benzo[ij]quinolizine-9-yl [4H-pyran-4-ylidene]propanedinitrile (abbreviated as DCJTI ), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3 ,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl ]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2 ,6-Bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4- 2-{2,6-bis[2-(8 -Methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5 H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene} Propanedinitrile (abbreviation: BisDCJTM), 5,10,15,20-tetraphenyl Rubisbenzo[5,6]indeno[1,2,3-cd:1',2',3'-lm]perylene Examples include:

[0214] In the light-emitting layer 120, materials that can be used as the host material 121 include: Although there is no particular limitation, for example, tris(8-quinolinolato)aluminum(III) (abbreviation : Alq), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq3), bis(10-hydroxybenzo[h]quinolinato)beryllium(II)( Abbreviation: BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato) ) Aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II)( Abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phenolato]zinc(II) ( abbreviation: ZnBTZ), metal complexes such as 2-(4-biphenylyl)-5-(4-tert- butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5 -(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene 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-benzimidazoline) TPBI), bathophenanthroline (BPhen), bathocuproline BCP, 9-[4-(5-phenyl-1,3,4-oxadiazole-2- Heterocyclic compounds such as 4,4-phenyl-9H-carbazole (abbreviation: CO11), '-Bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as NPB) is 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 Aromatic amine compounds such as benzophenone (BSPB) are also suitable. Nanthrene derivatives, pyrene derivatives, chrysene derivatives, dibenzo[g,p]chrysene derivatives Condensed polycyclic aromatic compounds such as 9,10-diphenylanthracene are specifically exemplified. (abbreviation: DPAnth), N,N-diphenyl-9-[4-(10-phenyl-9-anthracene] tolyl)phenyl]-9H-carbazol-3-amine (abbreviation: CzA1PA), 4-( 10-phenyl-9-anthryl)triphenylamine (abbreviation: DPhPA), 4-(9 H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)tripheny YGAPA, N,9-diphenyl-N-[4-(10-phenyl-9 -anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), N ,9-diphenyl-N-{4-[4-(10-phenyl-9-anthryl)phenyl]phenyl {phenyl}-9H-carbazol-3-amine (abbreviation: PCAPBA), N,9-diphenyl N-(9,10-diphenyl-2-anthryl)-9H-carbazol-3-amine (abbreviation: 2PCAPA), 6,12-dimethoxy-5,11-diphenylchrysene, N, N,N',N',N'',N'',N''',N'''-octaphenyldibenzo[g, p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), 9-[4-(1 0-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: CzPA), 3,6-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H -carbazole (abbreviation: DPCzPA), 9,10-bis(3,5-diphenylphenyl) ) anthracene (abbreviation: DPPA), 9,10-di(2-naphthyl)anthracene (abbreviation: :DNA), 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation :t-BuDNA), 9,9'-bianthryl (abbreviation: BANT), 9,9'-(styryl) 9,9'-(stilbene-3,3'-diyl)diphenanthrene (abbreviation: DPNS), 3,3',3''-(phenyl-4,4'-diyl)diphenanthrene (abbreviation: DPNS2), Benzene-1,3,5-triyl)tripylene (abbreviation: TPB3) In addition, from among these and known substances, the energy gap of the guest material 122 can be If one or more materials with a larger energy gap than the good.

[0215] The light-emitting layer 120 may be composed of two or more layers. When the light-emitting layer 120 is formed by laminating the first light-emitting layer and the second light-emitting layer in this order from the hole transport layer side, a substance having hole transport properties is used as a host material for the first light-emitting layer, and a substance having hole transport properties is used as a host material for the second light-emitting layer For example, a substance having an electron transport property is used as the light emitting element.

[0216] In the light-emitting layer 120, the host material 121 is composed of one kind of compound. Alternatively, the light-emitting layer 120 may be made up of a single compound or a plurality of compounds. The layer may contain materials other than the host material 121 and the guest material 122.

[0217] <Materials that can be used for the light-emitting layer 170> The light-emitting layer 170 can be made of any of the materials described above for the light-emitting layer 14 shown in the first embodiment. Materials that can be used for the light-emitting layer 140 can be used. By incorporating the above into the light-emitting layer 170, a light-emitting element with high luminous efficiency can be manufactured.

[0218] Furthermore, there is no limitation on the color of light emitted from the light-emitting materials contained in the light-emitting layer 120 and the light-emitting layer 170. The light emitted from each of them is mixed and extracted from the device. Therefore, for example, if the emission colors of both are complementary to each other, the light-emitting element will emit white light. In consideration of the reliability of the light-emitting device, the light-emitting material contained in the light-emitting layer 120 The emission peak wavelength of the light-emitting material contained in the light-emitting layer 170 is preferably shorter than that of the light-emitting material contained in the light-emitting layer 170 .

[0219] The light-emitting unit 106, the light-emitting unit 108, and the charge generating layer 115 are formed by evaporation ( (including vacuum deposition), inkjet printing, coating, gravure printing, etc. can be done.

[0220] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. You can be there.

[0221] (Embodiment 3) In this embodiment mode, a light-emitting element having a different structure from those shown in Embodiment Modes 1 and 2 will be described. An example of this will be described below with reference to FIGS.

[0222] <Configuration example 1 of light-emitting element> 5(A) and 5(B) are cross-sectional views illustrating a light-emitting element according to one embodiment of the present invention. In (B), the parts having the same functions as those shown in (A) are marked with the same hatching. In addition, parts with similar functions will be marked with similar symbols. In some cases, symbols are used and detailed descriptions thereof are omitted.

[0223] The light emitting element 260a and the light emitting element 260b shown in FIGS. 5(A) and 5(B) emit light toward the substrate 200. The light emitting element may be a bottom emission type light emitting element that extracts light from the substrate 200. It may also be a top emission type light emitting element that extracts light in the opposite direction. Note that one embodiment of the present invention is not limited to this. Light emitted from the light-emitting element may be projected from above and below the substrate 200. It may also be a dual emission type light emitting element in which light is extracted both upward and downward. .

[0224] When the light emitting element 260a and the light emitting element 260b are bottom emission type, the electrode 1 The electrode 101 preferably has a function of transmitting light. Alternatively, the light emitting element 260a and the light emitting element 260b may have a function of In the case of a top emission type, the electrode 101 preferably has a function of reflecting light. In addition, the electrode 102 preferably has a function of transmitting light.

[0225] The light emitting element 260a and the light emitting element 260b are formed by providing an electrode 101 and an electrode 102 on a substrate 200. Between the electrode 101 and the electrode 102, there is provided a light-emitting layer 123B and a light-emitting layer 123C. G and a light-emitting layer 123R. Also, the light-emitting layer 123B has a hole injection layer 111, a hole transport layer 112, It has an electron transport layer 118 and an electron injection layer 119 .

[0226] The light-emitting element 260b includes a conductive layer 101a and a conductive The conductive layer 101b is located above the conductive layer 101a, and the conductive layer 101c is located below the conductive layer 101a. That is, in the light emitting element 260b, the conductive layer 101a is made up of the conductive layer 101b and the conductive layer 101c. It has a sandwiched electrode 101 configuration.

[0227] In the light emitting element 260b, the conductive layer 101b and the conductive layer 101c are made of different materials. The electrodes 101 may be sandwiched between the same conductive material. In the case where the electrode 101 has a structure in which the pattern is formed by an etching process, This is preferable because it makes the synthesis easier.

[0228] In the light-emitting element 260b, the conductive layer 101b or the conductive layer 101c A configuration having only one of them may also be used.

[0229] The conductive layers 101a, 101b, and 101c of the electrode 101 are each The same structure and material as the electrode 101 or the electrode 102 shown in the first embodiment can be used. Cut.

[0230] In FIGS. 5(A) and 5(B), the region 221B sandwiched between the electrode 101 and the electrode 102, A partition wall 145 is provided between the region 221G and the region 221R. The partition wall 145 has insulating properties. The partition 145 covers the end of the electrode 101 and has an opening that overlaps the electrode. By providing the walls 145, the electrodes 101 on the substrate 200 in each region are arranged in an island shape. It becomes possible to separate them.

[0231] In addition, in the region where the light-emitting layer 123B and the light-emitting layer 123G overlap with the partition wall 145, Alternatively, the light-emitting layer 123G and the light-emitting layer 123R may have overlapping regions. In the region where they overlap with the partition wall 145, they may have regions where they overlap each other. The light-emitting layer 123R and the light-emitting layer 123B are mutually overlapping in the region where they overlap with the partition wall 145. It may have an overlapping area.

[0232] The partition wall 145 may be formed using an inorganic or organic material as long as it has insulating properties. The inorganic material may be silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, or the like. Examples of the organic material include silicon, aluminum oxide, and aluminum nitride. For example, photosensitive resin materials such as acrylic resin or polyimide resin can be used.

[0233] The silicon oxynitride 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 % or less. Silicon is 25 atomic % or more and 35 atomic % or less, and hydrogen is 0.1 atomic % or more and 10 atomic % or less The silicon nitride oxide film is a film that contains more nitrogen than oxygen as its composition. It refers to a film with a high content of nitrogen, preferably 55 atomic % to 65 atomic % and 100 atomic % of oxygen. % or more and 20 atomic % or less, silicon is 25 atomic % or more and 35 atomic % or less, hydrogen is 0.1 atomic % or more This refers to a film containing this element in a concentration range of 1 atomic % to 10 atomic %.

[0234] The light-emitting layers 123R, 123G, and 123B each emit a different color. For example, the light-emitting layer 123R preferably has a light-emitting material that emits red light. By including a light-emitting material having a function of emitting red light, the region 221R emits red light, and Since the region 123G has a light-emitting material having a function of emitting green light, the region 221G emits green light. The light-emitting layer 123B has a light-emitting material that has a function of emitting blue light, so that the region 2 The light emitting element 260a or the light emitting element 21B emits blue light. By using 260b as a pixel of a display device, a display device capable of full color display can be manufactured. The thickness of each light-emitting layer may be the same or different. That's fine.

[0235] In addition, any one of the light-emitting layer 123B, the light-emitting layer 123G, and the light-emitting layer 123R or The plurality of light-emitting layers preferably have the same structure as the light-emitting layer 140 shown in the first embodiment. In this way, a light-emitting element with high luminous efficiency can be manufactured.

[0236] In addition, any one or more of the light-emitting layer 123B, the light-emitting layer 123G, and the light-emitting layer 123R The light-emitting layer may have a structure in which two or more layers are laminated.

[0237] As described above, at least one light-emitting layer has the light-emitting properties shown in the first and second embodiments. The light emitting element 260a or the light emitting element 260b having the light emitting layer is used in a display device. By using the organic EL element in the pixel of a display device, a display device with high luminous efficiency can be manufactured. A display device having the light-emitting element 260a or the light-emitting element 260b can reduce power consumption. can be done.

[0238] In addition, if an optical element (for example, a color filter, By providing a polarizing plate, an anti-reflection film, etc., the color purity of the light emitting element 260a and the light emitting element 260b can be improved. Therefore, the light emitting element 260a or the light emitting element 260b is effectively used. Alternatively, the color purity of the display device can be improved. Therefore, the light emitting element 260a or the light emitting element 260b can be prevented from reflecting external light. The contrast ratio of a display device having the element 260b can be increased.

[0239] Other configurations of the light emitting element 260a and the light emitting element 260b are the same as those in the embodiment. The structures of the light-emitting elements in Embodiments 1 and 2 may be referred to.

[0240] <Configuration example 2 of light-emitting element> Next, regarding a configuration example different from that of the light-emitting element shown in FIGS. 5(A) and 5(B), FIGS. 6(A) and 6(B) are shown. The following description will be given using this.

[0241] 6(A) and 6(B) are cross-sectional views showing a light-emitting element of one embodiment of the present invention. 5(A) and (B), the same symbols are used for the parts having the same functions as those shown in FIGS. In some cases, the hatch pattern is used and the symbols are omitted. Also, parts with similar functions are indicated by The same reference numerals are used and detailed descriptions thereof may be omitted.

[0242] 6A and 6B show examples of the structure of a light-emitting element having a light-emitting layer between a pair of electrodes. The light emitting element 262a shown in (A) is a top-emitting (top-emitting) element that extracts light in the direction opposite to the substrate 200. The light emitting element 262b shown in FIG. 6(B) is a top-emission type light emitting element. However, the present invention One embodiment is not limited to this, and light emitted by the light emitting element may be emitted from the substrate 200 on which the light emitting element is formed. It may also be a dual emission type in which light is extracted from both the top and bottom.

[0243] The light emitting element 262a and the light emitting element 262b are formed by providing an electrode 101 and an electrode 102 on a substrate 200. , electrode 103, and electrode 104. Also, between electrode 101 and electrode 102, and At least a light-emitting layer is formed between the electrode 102 and the electrode 103 and between the electrode 102 and the electrode 104. layer 170, a light-emitting layer 190, and a charge-generating layer 115. Also, a hole-injecting layer 111 and , a hole transport layer 112, an electron transport layer 113, an electron injection layer 114, and a hole injection layer 116. , a hole transport layer 117 , an electron transport layer 118 , and an electron injection layer 119 .

[0244] The electrode 101 includes a conductive layer 101a and a conductive layer 101b that is in contact with the conductive layer 101a. The electrode 103 includes a conductive layer 103a and a conductive layer 103b on and in contact with the conductive layer 103a. The electrode 104 has a conductive layer 104a and a conductive layer 103b on the conductive layer 104a. and an insulating layer 104b.

[0245] The light emitting element 262a shown in FIG. 6(A) and the light emitting element 262b shown in FIG. 6(B) have electrodes The area 222B sandwiched between the electrode 101 and the electrode 102, and the area 222B sandwiched between the electrode 102 and the electrode 103 and a region 222R sandwiched between the electrode 102 and the electrode 104. The partition wall 145 has an insulating property. The partition wall 145 is provided between the electrode 101 and the electrode 1 The separator 145 covers the end of the electrode 103 and the electrode 104 and has an opening overlapping the electrode. By doing so, the electrodes on the substrate 200 in each region can be separated into islands. It becomes Noh.

[0246] The charge generation layer 115 is formed by adding an electron acceptor to a hole transporting material. or an electron transporting material to which an electron donor (donor) is added, In addition, when the conductivity of the charge generating layer 115 is as high as that of the pair of electrodes, In this case, carriers generated by the charge generating layer 115 flow to the adjacent pixels, Therefore, it is necessary to prevent adjacent pixels from emitting light incorrectly. To achieve this, the charge generation layer 115 is formed of a material having a lower conductivity than the pair of electrodes. preferable.

[0247] The light emitting element 262a and the light emitting element 262b are arranged in the regions 222B, 222G, and The optical element 224B and the optical element 224C are arranged in the direction in which the light emitted from the region 222R is extracted. The substrate 220 has the optical element 224G and the optical element 224R. The light emitted from the region 222B is emitted to the outside of the light emitting element through each optical element. The light coming from the region 222G is emitted through the optical element 224B. The light emitted through 224G and emitted from the region 222R is reflected by the optical element 224R. It is ejected.

[0248] Furthermore, the optical elements 224B, 224G, and 224R are configured to For example, the optical element 224B has a function of selectively transmitting light of a specific color. The light emitted from the region 222B through the optical element 22 is blue light. The light emitted from the area 222G via the optical element 4G is green light. The light emitted from the region 222R via the element 224R is red light.

[0249] The optical elements 224R, 224G, and 224B may include, for example, a colored layer ( Color filters, bandpass filters, multilayer filters, etc. can be used. In addition, a color conversion element can be applied to the optical element. The color conversion element is an optical element that converts light into light with a longer wavelength than the wavelength of the light. By using quantum dots, the color reproducibility of the display device can be improved. can be increased.

[0250] It should be noted that if other optical elements are arranged on the optical elements 224R, 224G, and 224B, Other optical elements may be provided, for example, a circular polarizing plate or an anti-reflection plate. The circular polarizer is placed in a position where the light emitted by the light emitting element of the display device is extracted. When the light source is provided on the side where the light source is located, the light incident from outside the display device is reflected inside the display device and Furthermore, by providing an anti-reflection film, the surface of the display device can be prevented from being irradiated. This reduces the amount of external light reflected by the display device, making it possible to clearly see the light emitted by the display device. It can be observed.

[0251] In addition, in FIG. 6(A)(B), the light emitted from each region via each optical element is Light exhibiting color (B), light exhibiting green (G), and light exhibiting red (R), respectively. This is shown schematically by dashed arrows.

[0252] In addition, a light-shielding layer 223 is provided between each optical element. The light-shielding layer 223 is formed to prevent light from entering from adjacent regions. It should be noted that the light-shielding layer 223 may not be provided. stomach.

[0253] The light-shielding layer 223 has a function of suppressing reflection of external light. The light-shielding layer 223 has a function of preventing the color mixture of light emitted from adjacent light-emitting elements. Examples include metals, resins containing black pigments, carbon black, metal oxides, and multiple metal oxides. A composite oxide containing a solid solution of such a material can be used.

[0254] The optical elements 224B and 224G overlap with the light-shielding layer 223. Alternatively, the optical element 224G and the optical element 224R is a region overlapping with the light-shielding layer 223, even if they have overlapping regions. Alternatively, the optical element 224R and the optical element 224B may overlap with the light-shielding layer 223. The regions may have overlapping regions.

[0255] The substrate 200 and the substrate 220 having the optical element are configured as in the first embodiment. Please take this into consideration.

[0256] Furthermore, the light emitting element 262a and the light emitting element 262b have a microcavity structure. .

[0257] <Microcavity structure> The light emitted from the light-emitting layer 170 and the light-emitting layer 190 is incident on a pair of electrodes (for example, electrode 10 The light emitting layer 170 and the light emitting layer 190 are resonated between the electrode 101 and the electrode 102. For example, the reflection area of ​​the electrode 101 is formed at a position where light of a desired wavelength is intensified. the optical distance from the reflecting area of ​​the electrode 102 to the light emitting area of ​​the light emitting layer 170; By adjusting the optical distance to the light emitting region, the amount of light emitted from the light emitting layer 170 can be reduced. In addition, the light emitted from the reflective region of the electrode 101 to the light emitting layer 190 can be intensified. and the optical distance from the reflective area of ​​the electrode 102 to the light-emitting area of ​​the light-emitting layer 190. By adjusting the optical distance, it is possible to obtain light of a desired wavelength from the light emitting layer 190. That is, the light can be intensified by using a plurality of light-emitting layers (here, the light-emitting layer 170 and the light-emitting layer In the case of a light emitting device in which the light emitting layer 170 and the light emitting layer 190 are stacked, the optical distances of the light emitting layer 170 and the light emitting layer 190 are It is preferable to optimize the separation.

[0258] In the light emitting element 262a and the light emitting element 262b, the conductive layer (conductive layer 1) is formed in each region. By adjusting the thickness of the conductive layer 101b, the conductive layer 103b, and the conductive layer 104b, the light-emitting layer 170 In addition, it is possible to enhance light of a desired wavelength among the light emitted from the light emitting layer 190. The thickness of at least one of the hole injection layer 111 and the hole transport layer 112 is made different in the region. This may intensify the light emitted from light-emitting layer 170 and light-emitting layer 190.

[0259] For example, the electrodes 101 to 104 are made of a conductive material having a function of reflecting light. When the refractive index is smaller than that of the light-emitting layer 170 or the light-emitting layer 190, the electrode The thickness of the conductive layer 101b of the electrode 101 is set so that the optical distance between the electrode 101 and the electrode 102 is m B λ B / 2(m B is a natural number, λ B represent the wavelengths of light to be intensified in region 222B, respectively) and Similarly, the thickness of the conductive layer 103b of the electrode 103 is adjusted to be equal to the thickness of the conductive layer 103b of the electrode 103. The optical distance between the electrode 102 is m G λ G / 2(m G is a natural number, λ G is strong in the area 222G The wavelength of the light emitted from the electrode 104 is adjusted to be 100 nm. The thickness of the electrode 104b is set such that the optical distance between the electrode 104 and the electrode 102 is m R λ R / 2(m R is self natural number, λ R and represent the wavelengths of the light to be intensified in the region 222R).

[0260] In addition, when it is difficult to precisely determine the reflective areas of the electrodes 101 to 104, By assuming that any region of the light-emitting layer 170 or the light-emitting electrode 101 to the electrode 104 is a reflective region, An optical path that enhances the light emitted from the light emitting layer 190 may be derived. When it is difficult to precisely determine the light-emitting region of the light-emitting layer 170 and the light-emitting layer 190, By assuming that any region of the light emitting layer 190 is a light emitting region, the light emitting layer 170 and the light emitting layer 190 An optical path that enhances the light emitted from the

[0261] As described above, a microcavity structure is provided, and the optical distance between a pair of electrodes in each region is adjusted. By adjusting the thickness, light scattering and absorption near each electrode are suppressed, resulting in high light extraction efficiency. The rate can be realized.

[0262] In the above structure, the conductive layer 101b, the conductive layer 103b, and the conductive layer 104b are optically It is preferable that the conductive layer 101b, the conductive layer 103b, and the conductive The materials constituting the layers 104a and 104b may be the same or different. When the same material is used for the conductive layer 101b, the conductive layer 103b, and the conductive layer 104b, the electrode 10 1. The pattern formation by the etching process in the process of forming the electrodes 103 and 104 is easy. In addition, the conductive layers 101b, 103b, and 104b are preferably Each of these may have a structure in which two or more layers are laminated.

[0263] Since the light emitting element 262a shown in FIG. 6A is a top emission type light emitting element, the conductive layer The conductive layers 101a, 103a, and 104a preferably have a function of reflecting light. In addition, the electrode 102 preferably has a function of transmitting light and a function of reflecting light. preferable.

[0264] Furthermore, the light emitting element 262b shown in FIG. 6B is a bottom emission type light emitting element, and therefore has no conductive The layer 101a, the conductive layer 103a, and the conductive layer 104a have a function of transmitting light and a function of reflecting light. It is preferable that the electrode 102 has a function of reflecting light. preferable.

[0265] In the light-emitting element 262a and the light-emitting element 262b, the conductive layer 101a and the conductive layer 10 The same material may be used for the conductive layer 3a or the conductive layer 104a, or different materials may be used. When the same material is used for the conductive layer 101a, the conductive layer 103a, and the conductive layer 104a, the light emitting element The manufacturing costs of the conductive layer 101a and the light emitting element 262a and the light emitting element 262b can be reduced. The conductive layer 103a and the conductive layer 104a may each have a structure in which two or more layers are stacked. stomach.

[0266] In addition, the light-emitting layer 170 and the light-emitting layer 190 in the light-emitting element 262a and the light-emitting element 262b At least one of the above has at least one of the configurations shown in the first and second embodiments. By doing so, it is possible to manufacture a light-emitting element that exhibits high luminous efficiency. can be done.

[0267] The light-emitting layer 170 and the light-emitting layer 190 are, for example, the light-emitting layer 190a and the light-emitting layer 190b. In this way, two layers may be laminated on one or both sides. The first compound and the second compound are two types of luminescent materials that have the function of exhibiting different colors. By using each of them, multiple lights can be emitted simultaneously. The luminescent material used in each luminescent layer is selected so that the luminescence exhibited by 190 becomes white. This is preferable.

[0268] In addition, the light-emitting layer 170 or the light-emitting layer 190 may have a structure in which three or more layers are laminated on one side or both sides. The light-emitting layer may be made of any material, or may include a layer that does not contain a light-emitting material.

[0269] As described above, the present invention can be realized by using at least one of the structures of the light-emitting layer shown in Embodiments 1 and 2. By using the light-emitting element 262a or the light-emitting element 262b having the same in a pixel of a display device, A display device with high light efficiency can be manufactured. A display device including the element 262b can consume less power.

[0270] Other configurations of the light emitting element 262a and the light emitting element 262b are as follows: 260a or 260b, or the light-emitting element shown in the first and second embodiments. The configuration of the optical element should be taken into consideration.

[0271] <Method for manufacturing light-emitting elements> Next, a manufacturing method of a light-emitting element of one embodiment of the present invention will be described below with reference to FIGS. 7 and 8. Here, a method for manufacturing the light-emitting element 262a shown in FIG. do.

[0272] 7 and 8 are cross-sectional views illustrating a method for manufacturing a light-emitting element according to one embodiment of the present invention. .

[0273] The method for fabricating the light emitting element 262a described below includes seven steps, namely, first to seventh steps. do.

[0274] <First Step> The first step is to form an electrode (specifically, a conductive layer 101) of the light-emitting element. a, conductive layer 103a constituting electrode 103, and conductive layer 104a constituting electrode 104) is a step of forming the above on a substrate 200 (see FIG. 7(A)).

[0275] In this embodiment, a conductive layer having a function of reflecting light is formed on a substrate 200. The conductive layer is processed into a desired shape, whereby the conductive layer 101a, the conductive layer 103a, and the conductive layer 104a are formed. The conductive layer 104a is formed by using silver and palladium. The film is made of an alloy of Ag and copper (also called Ag-Pd-Cu film or APC). The conductive layer 101a, the conductive layer 103a, and the conductive layer 104a are formed by a process of processing the same conductive layer. Forming the wiring board through this process is preferable because it reduces the manufacturing cost.

[0276] It should be noted that a plurality of transistors may be formed on the substrate 200 before the first step. In addition, the plurality of transistors, the conductive layer 101a, the conductive layer 103a, and the conductive layer 104a may be electrically connected to each other.

[0277] <<Second Step>> In the second step, a light-transmitting layer is formed on the conductive layer 101a constituting the electrode 101. The conductive layer 101b is formed on the conductive layer 103a constituting the electrode 103. The conductive layer 103b is formed on the conductive layer 104a of the electrode 104. This is a step of forming a conductive layer 104b (see FIG. 7(B)).

[0278] In this embodiment, the conductive layers 101a and 103a, which have a function of reflecting light, 104a, and 101b, respectively, are provided on the conductive layers 101b, 103b, and 104a, respectively, which have a light transmitting function. By forming the electrode 104b, the electrode 101, the electrode 103, and the electrode 104 are formed. The conductive layers 101b, 103b, and 104b are made of ITSO films.

[0279] The conductive layers 101b, 103b, and 104b having a function of transmitting light are formed multiple times. By forming the microcapsules in multiple steps, it is possible to form the microcapsules in each area. The conductive layers 101b, 103b, and 104b can be formed to a thickness that provides a cavity structure. Cut.

[0280] <Third Step> The third step is to form the partition walls 145 that cover the edges of the electrodes of the light-emitting element ( See Figure 7(C)).

[0281] The partition wall 145 has an opening so as to overlap with the electrode. In this embodiment, the partition wall 145 is made of a polyimide resin. Use fat.

[0282] In the first to third steps, the EL layer (layer containing an organic compound) is not damaged. Since there is no risk of this, various film forming methods and microfabrication techniques can be applied. The method uses a sputtering method to form a reflective conductive layer, and then uses a lithography method to form a reflective conductive layer. A pattern is formed on the conductive layer, and then the pattern is formed by dry etching or wet etching. The conductive layer is processed into an island shape, whereby the conductive layer 101a constituting the electrode 101 and the electrode 10 A conductive layer 103a constituting the electrode 3 and a conductive layer 104a constituting the electrode 104 are formed. Thereafter, a transparent conductive film is formed by sputtering, and then a lithography method is used. Then, a pattern is formed on the transparent conductive film, and then the pattern is removed by wet etching. The transparent conductive film is then processed into islands to form electrodes 101, 103, and 104. do.

[0283] <Fourth Step> The fourth step is to form a hole injection layer 111, a hole transport layer 112, an emissive layer 190, an electron transport layer This is a step of forming a layer 113, an electron injection layer 114, and a charge generation layer 115 (see FIG. 8(A)). (see).

[0284] The hole injection layer 111 is formed by co-evaporating a hole transporting material and a material containing an acceptor material. Co-evaporation is the process of depositing different materials on different surfaces. The hole transport layer 112 is a vapor deposition method in which the hole It can be formed by vapor deposition of a transport material.

[0285] The light-emitting layer 190 may be purple, blue, blue-green, green, yellow-green, yellow, orange, or red. The resulting film is formed by depositing at least one luminescent guest material selected from the following: As the guest material, a light-emitting organic material that exhibits fluorescence or phosphorescence can be used. In addition, the light-emitting layer having the structure shown in Embodiment 1 and Embodiment 2 can be used. It is preferable that the light-emitting layer 190 has a two-layer structure. The light-emitting layers preferably contain light-emitting materials that emit light of different colors.

[0286] The electron transporting layer 113 can be formed by evaporating a substance with a high electron transporting property. The electron injection layer 114 can be formed by evaporating a material with high electron injection properties. It is possible.

[0287] The charge generation layer 115 is made of a material in which an electron acceptor is added to a hole transporting material. or a material in which an electron donor (donor) is added to an electron transporting material. It can be formed by

[0288] <5th step> The fifth step is to deposit the hole injection layer 116, the hole transport layer 117, the light emitting layer 170, and the electron transport layer 118. This is a step of forming the insulating layer 118, the electron injection layer 119, and the electrode 102 (see FIG. 8B).

[0289] The hole injection layer 116 is formed using the same material and method as the hole injection layer 111 described above. The hole transport layer 117 can be formed by the above-described hole transport layer 11. It can be formed using the same materials and methods as in 2.

[0290] The light-emitting layer 170 may be purple, blue, blue-green, green, yellow-green, yellow, orange, or red. The resulting film is formed by depositing at least one luminescent guest material selected from the following: The guest material can be a light-emitting organic compound that exhibits fluorescence or phosphorescence. In addition, the light-emitting layer having the structure shown in Embodiment 1 and Embodiment 2 can be used. It is preferable that at least one of the light-emitting layer 170 and the light-emitting layer 190 is It is preferable that the light-emitting layer has the configuration shown in Form 1. In addition, the light-emitting layer 170 and the light-emitting layer 1 90 preferably contains luminescent organic compounds that have the function of exhibiting different luminescence from each other. .

[0291] The electron transport layer 118 is formed using the same material and method as the electron transport layer 113 described above. The electron injection layer 119 can be formed by the above-described electron injection layer 11. It can be formed using the same materials and methods as in 4.

[0292] The electrode 102 is formed by stacking a reflective conductive film and a light-transmitting conductive film. The electrode 102 can be formed as a single layer structure or a stacked layer structure. Good too.

[0293] Through the above steps, regions 222 are formed on the electrodes 101, 103, and 104, respectively. A light-emitting device having regions 222B, 222G, and 222R is formed on substrate 200.

[0294] <Sixth Step> In the sixth step, the light-shielding layer 223, the optical element 224B, and the optical element 224 are formed on the substrate 220. This is a step of forming the optical element 224G and the optical element 224R (see FIG. 8(C)).

[0295] The light-shielding layer 223 is formed by forming a resin film containing a black pigment in a desired area. On the plate 220 and the light-shielding layer 223, an optical element 224B, an optical element 224G, and an optical element 224G are provided. As the optical element 224B, a resin film containing a blue pigment is applied to a desired area. In addition, as the optical element 224G, a resin film containing a green pigment is formed in a desired area. In addition, the optical element 224R is formed by forming a resin film containing a red pigment in a desired area. do.

[0296] <Seventh Step> The seventh step is to separate the light emitting element formed on the substrate 200 and the light emitting element formed on the substrate 220. The light-shielding layer 223, the optical element 224B, the optical element 224G, and the optical element 224R are bonded together. This is a process of joining the components together and sealing them with a sealant (not shown).

[0297] Through the above steps, the light-emitting element 262a shown in FIG. 6(A) can be formed.

[0298] Note that the structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. You can be there.

[0299] (Fourth embodiment) In this embodiment, a display device of one embodiment of the present invention will be described with reference to FIGS. do.

[0300] <Display device configuration example 1> 9A is a top view showing the display device 600, and FIG. 9B is a diagram showing the display device 600 along the dashed line AB in FIG. 9A. 1 and a cross-sectional view taken along dashed line CD. The display device 600 includes a drive circuit section (signal line The display device includes a driver circuit portion 601, a scanning line driver circuit portion 603, and a pixel portion 602. The signal line driver circuit portion 601, the scanning line driver circuit portion 603, and the pixel portion 602 are It has the function of controlling light emission.

[0301] The display device 600 also includes an element substrate 610, a sealing substrate 604, a sealant 605, The device has an area 607 surrounded by a sealing material 605, wiring 608, and an FPC 609. do.

[0302] The lead wiring 608 is connected to the signal line driver circuit portion 601 and the scanning line driver circuit portion 603. This is the wiring for transmitting the input signal, and is connected to the external input terminal FPC609. It receives the FP signal, clock signal, start signal, reset signal, etc. Although only C609 is shown, FPC609 has a printed wiring board (PWB). A wired wiring board may be installed.

[0303] The signal line driver circuit portion 601 includes an N-channel transistor 623 and a P-channel transistor A CMOS circuit is formed by combining this transistor 624. The path section 601 or the scanning line driving circuit section 603 may be implemented by various CMOS circuits, PMOS circuits, or In this embodiment, a driving circuit section is provided on the substrate. Although the display device shown has the formed driver and pixel on the same surface, this is not necessarily required. In addition, the drive circuit section can be formed externally rather than on the substrate.

[0304] The pixel portion 602 includes a switching transistor 611 and a current control transistor. a lower part electrically connected to the drain of the current control transistor 612; A partition wall 614 is formed to cover the edge of the lower electrode 613. The partition wall 614 can be made of a positive photosensitive acrylic resin film.

[0305] In order to improve the covering property, the partition wall 614 is provided with a curved surface having a curvature at the upper end or the lower end. For example, the partition wall 614 is made of a positive photosensitive acrylic. In this case, only the upper end of the partition wall 614 is curved to have a radius of curvature (0.2 μm or more and 3 μm or less). It is preferable that the partition wall 614 is made of a negative photosensitive resin or a polyimide. Any of the photosensitive resins of the di-type can be used.

[0306] The structure of the transistors (transistors 611, 612, 623, and 624) is For example, a staggered transistor may be used. There is no particular limitation on the polarity, and it has N-channel and P-channel transistors. and either an N-channel transistor or a P-channel transistor. A structure consisting of only one of the two may also be used. For example, an amorphous semiconductor film or a crystalline semiconductor film can be used. Semiconductor materials include group 14 (silicon, etc.) semiconductors, compound semiconductors (oxide As the transistor, for example, An energy gap of 2 eV or more, preferably 2.5 eV or more, and more preferably 3 eV or more By using the oxide semiconductor, the off-state current of the transistor can be reduced. As the oxide semiconductor, 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 nickel Examples include neodymium (Nd).

[0307] An EL layer 616 and an upper electrode 617 are formed on the lower electrode 613. The lower electrode 613 functions as an anode, and the upper electrode 617 functions as a cathode. do.

[0308] The EL layer 616 can be formed by a deposition method using a deposition mask, an inkjet method, or a spin coating method. The EL layer 616 can be formed by various methods such as a low-temperature method. The compound may be a molecular compound or a polymer compound (including an oligomer or a dendrimer).

[0309] The lower electrode 613, the EL layer 616, and the upper electrode 617 form a light-emitting element 618. The light emitting element 618 has the structure of any one of the first to third embodiments. In addition, when a plurality of light-emitting elements are formed in a pixel portion, the same as those in Embodiments 1 to 4 are preferably used. The light-emitting element according to the third embodiment and the light-emitting element having other structures are both included. That's fine.

[0310] In addition, by bonding the sealing substrate 604 to the element substrate 610 with the sealing material 605, The light-emitting element is disposed in an area 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealing material 605. The region 607 is filled with a filler. In addition to being filled with an inert gas (nitrogen, argon, etc.), it can also be used as a sealing material 605. They may also be filled with UV or heat curable resins that can be used for various applications, such as PVC ( Polyvinyl chloride) resin, acrylic resin, polyimide resin, epoxy resin, Silicone resin, PVB (Polyvinyl Butyral) resin, or EVA (Ethylene Vinyl A recess is formed in the sealing substrate, and a desiccant (acetate) resin is placed therein. By providing this, deterioration due to the influence of moisture can be suppressed, which is a preferable configuration.

[0311] In addition, the optical element 621 is disposed below the sealing substrate 604 so as to overlap the light emitting element 618. In addition, a light-shielding layer 622 is provided below the sealing substrate 604. The optical element and the light-shielding layer 621 and the light-shielding layer 622 are respectively the optical element and the light-shielding layer shown in the third embodiment. The same configuration may be used.

[0312] It is preferable to use epoxy resin or glass frit for the sealing material 605. In addition, it is desirable that these materials be as impermeable to moisture and oxygen as possible. In addition, the material used for the sealing substrate 604 may be a glass substrate, a quartz substrate, or an FRP (Fiber Reinforced Plastic) substrate. Reinforced Plastics), PVF (Polyvinyl Fluoride), Poly A plastic substrate made of ester, acrylic or the like can be used.

[0313] As described above, the light emitting element and the optical element described in any of the first to third embodiments are used. A display device can be obtained.

[0314] <Configuration example 2 of the display device> Next, another example of the display device will be described with reference to FIGS. 10(A), 10(B) and 11. 10A, 10B, and 11 are cross-sectional views of display devices according to embodiments of the present invention. .

[0315] FIG. 10A shows a substrate 1001, an underlying insulating film 1002, a gate insulating film 1003, a gate Electrodes 1006, 1007, 1008, a first interlayer insulating film 1020, a second interlayer insulating film 10 21, peripheral portion 1042, pixel portion 1040, driving 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, a sealing layer 1029, a sealing substrate 1031, a sealing material 1032, etc. are shown. .

[0316] In addition, in FIG. 10(A), as an example of an optical element, a colored layer (a red colored layer 1034R, A green colored layer 1034G and a blue colored layer 1034B are provided on a transparent substrate 1033. A light-shielding layer 1035 may be further provided. The base material 1033 is aligned and fixed to the substrate 1001. is covered with an overcoat layer 1036. In FIG. 10(A), the colored layer Since the light that passes through the screen is red, green, and blue, images can be displayed using three color pixels.

[0317] In FIG. 10B, as an example of an optical element, a colored layer (a red colored layer 1034R, a green colored layer The colored layer 1034G and the blue colored layer 1034B are formed between the gate insulating film 1003 and the first interlayer insulating film. In this example, the colored layer is formed between the substrate 1001 and the film 1020. It may be provided between the substrates 1031 .

[0318] In FIG. 11, as an example of an optical element, colored layers (a red colored layer 1034R, a green colored layer 1034G, blue colored layer 1034B) between the first interlayer insulating film 1020 and the second interlayer insulating film In this example, the colored layer is formed between the substrate 1001 and the sealing substrate 1021. It may be provided between the plates 1031.

[0319] In the display device described above, the substrate 1001 side on which the transistors are formed is The display device has a structure for extracting light (bottom emission type), but The display device may also have a structure in which light is extracted (top emission type).

[0320] <Configuration example 3 of the display device> An example of a cross-sectional view of a top-emission type display device is shown in Figures 12(A) and 12(B). 10(A) and 10(B) are cross-sectional views illustrating a display device of one embodiment of the present invention. 11.) and the driving circuit section 1041, the peripheral section 1042, etc. shown in FIG. 11 are omitted in the illustration.

[0321] In this case, the substrate 1001 can be a substrate that does not transmit light. Until the connection electrode that connects to the anode of the optical element is fabricated, it is a bottom emission type display device. Then, a third interlayer insulating film 1037 is formed to cover the electrode 1022. This insulating film may also have a role of planarization. In addition to the same material as the interlayer insulating film 2, various other materials can be used.

[0322] The lower electrodes 1024R, 1024G, and 1024B of the light-emitting element are anodes here, but Also, top emission type displays as shown in Figure 12(A)(B) can be used. In the case of a device, the lower electrodes 1024R, 1024G, and 1024B have a function of reflecting light. In addition, an upper electrode 1026 is provided on the EL layer 1028. The electrode 1026 has a function of reflecting light and a function of transmitting light. A microcavity structure is adopted between 24G, 1024B and the upper electrode 1026, It is desirable to increase the light intensity at a particular wavelength.

[0323] In the top emission structure shown in FIG. 12(A), the colored layer (red colored layer 1034 A sealing substrate 1031 provided with a green colored layer 1034R, a green colored layer 1034G, and a blue colored layer 1034B The sealing substrate 1031 has a shielding layer positioned between the pixels. An optical layer 1035 may be provided. Note that the sealing substrate 1031 may be a light-transmitting substrate. It is suitable.

[0324] In addition, in FIG. 12(A), a plurality of light emitting elements and colored light emitting elements are provided. Although the configuration in which a layer is provided is shown as an example, the present invention is not limited to this. For example, as shown in FIG. In this case, the green color layer is not provided, and only the red color layer 1034R and the blue color layer 1034B are provided. It is also possible to use a configuration in which a full color display is performed using three colors, red, green, and blue. In this way, when a light emitting element and a colored layer are provided for each of the light emitting elements, reflection of external light can be reduced. On the other hand, as shown in FIG. 12(B), In the case where a red colored layer and a blue colored layer are provided without providing a colored layer of green, Since there is little energy loss in the light emitted from the light-emitting element, power consumption can be reduced. This has a positive effect.

[0325] <Display device configuration example 4> The display device described above has a configuration having sub-pixels of three colors (red, green, and blue). A structure with four color sub-pixels (red, green, blue, yellow, or red, green, blue, white) 13 to 15 show the lower electrodes 1024R, 1024G, 1024B, 13(A)(B) and 14 show the configuration of a display device having 1024Y. A structure in which light is extracted from the substrate 1001 side where the transistor is formed (bottom emission type) 15(A) and 15(B) show a structure in which light is extracted to the sealing substrate 1031 side ( It is a top-emission display device.

[0326] FIG. 13(A) shows the optical element (colored layer 1034R, colored layer 1034G, colored layer 1034B 13 is an example of a display device in which a colored layer 1034Y is provided on a transparent substrate 1033. (B) shows the optical elements (colored layer 1034R, colored layer 1034G, colored layer 1034B) in a gate. This is an example of a display device formed between the first insulating film 1003 and the first interlayer insulating film 1020. FIG. 14 shows the optical element (colored layer 1034R, colored layer 1034G, colored layer 1034B, A color layer 1034Y is formed between the first interlayer insulating film 1020 and the second interlayer insulating film 1021. This is an example of a display device.

[0327] The colored layer 1034R transmits red light, the colored layer 1034G transmits green light, and the colored layer The colored layer 1034B has a function of transmitting blue light, and the colored layer 1034Y has a function of transmitting yellow light. The ability to transmit multiple colors of light selected from blue, green, yellow, and red. The colored layer 1034Y transmits a plurality of light beams selected from blue, green, yellow, and red. When the colored layer 1034Y has a function of transmitting light, the light transmitted through the colored layer 1034Y may be white. Since the light emitting element that emits white light has high luminous efficiency, it is preferable to use the light emitting element that emits white light in the display having the colored layer 1034Y. The device can reduce power consumption.

[0328] In the top emission type display device shown in FIG. 15, the lower electrode 1024Y In the light-emitting element having the same structure, the upper electrode 1026 is connected to the light-emitting element 1026 in the same manner as in the display device of FIG. In addition, a display device having a microcavity structure is preferable. Now, the colored layers (red colored layer 1034R, green colored layer 1034G, blue colored layer 103 The sealing can be performed by a sealing substrate 1031 provided with a yellow colored layer 1034Y. do.

[0329] The light emitted through the microcavity and the yellow colored layer 1034Y is in the yellow region. Yellow is a color with high visibility, so yellow light is emitted. The light-emitting element exhibiting this has high luminous efficiency. , power consumption can be reduced.

[0330] In addition, in FIG. 15(A), a plurality of light emitting elements and colored light emitting elements are provided. Although the configuration in which a layer is provided is shown as an example, the present invention is not limited to this. For example, as shown in FIG. , the yellow colored layer is not provided, and the red colored layer 1034R, the green colored layer 1034G, and the blue colored layer 1034R are provided. A colored layer 1034B is provided to allow the four colors of red, green, blue, and yellow, or red, green, blue, and white. As shown in FIG. 15(A), a light-emitting element and the light-emitting element When a colored layer is provided on each optical element, it is possible to suppress the reflection of external light. On the other hand, as shown in FIG. 15(B), a light emitting element and a red coloring layer are not provided. When a colored layer of a color, a green colored layer, and a blue colored layer are provided, yellow or white Since there is little energy loss in the light emitted from the light-emitting element, power consumption can be reduced. This has a positive effect.

[0331] <Display Device Configuration Example 5> Next, a display device according to another embodiment of the present invention is shown in FIG. 16. FIG. 16 shows the same display device as FIG. 16 is a cross-sectional view taken along dashed lines AB and CD. 9B, the same reference numerals are used to designate parts having the same functions as those shown in FIG. 9B, and detailed explanations thereof will be omitted. The clarification is omitted.

[0332] The display device 600 shown in FIG. 16 includes an element substrate 610, a sealing substrate 604, and a sealing material 60 The region 607 surrounded by 5 has sealing layers 607a, 607b, and 607c. For example, one or more of the sealing layers 607a, 607b, and 607c may include For example, PVC (polyvinyl chloride) resin, acrylic resin, polyimide resin, epoxy resin, silicone resin, PVB (polyvinyl butyral) resin, or EVA Resins such as ethylene vinyl acetate resins can be used. silicon oxynitride, silicon nitride oxide, silicon nitride, aluminum oxide, aluminum nitride Alternatively, an inorganic material such as aluminum may be used. By forming the layer c, it is possible to suppress deterioration of the light emitting element 618 due to impurities such as water. It is preferable to form the sealing layer 607a, the sealing layer 607b, and the sealing layer 607c. The cooling material 605 does not need to be provided.

[0333] In addition, the sealing layer 607a, the sealing layer 607b, and the sealing layer 607c may be any one or two. Alternatively, four or more sealing layers may be formed. Impurities such as these may penetrate from the outside of the display device 600 to the light emitting element 618 inside the display device. In addition, when the sealing layer is multi-layered, the sealing layer may be made of a resin and an inorganic material. It is preferable to laminate the material.

[0334] <Display Device Configuration Example 6> The display devices shown in Configuration Examples 1 to 4 in this embodiment include optical elements. However, in one embodiment of the present invention, an optical element does not necessarily have to be provided.

[0335] The display device shown in FIG. 17(A)(B) has a structure in which light is extracted to the sealing substrate 1031 side (transistor). 17A shows a display device of a top emission type (top emission type). 1028R, light-emitting layer 1028G, and light-emitting layer 1028B. FIG. 17(B) shows that the EL layer 1028 includes a light-emitting layer 1028R, a light-emitting layer 1028G, and a light-emitting layer 1028G. 28B and a light-emitting layer 1028Y.

[0336] The light-emitting layer 1028R emits red light, the light-emitting layer 1028G emits green light, and The light-emitting layer 1028B has a function of emitting blue light. or a function of exhibiting multiple luminescence selected from blue, green, and red. The light emitted by the light-emitting layer 1028Y may be white. Since the light-emitting element that emits light has high luminous efficiency, the display device having the light-emitting layer 1028Y has high luminous efficiency. Power consumption can be reduced.

[0337] The display devices shown in FIGS. 17(A) and 17(B) have EL layers 10 that emit light of different colors. Since the sub-pixel has the colored layer 28, it is not necessary to provide a colored layer that serves as an optical element.

[0338] The sealing layer 1029 is made of, for example, a PVC (polyvinyl chloride) resin or an acrylic resin. resin, polyimide resin, epoxy resin, silicone resin, PVB (polyvinyl bromide) Resins such as ethylene vinyl acetate (EVA) resins can be used. In addition, silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride Alternatively, an inorganic material such as aluminum oxide or aluminum nitride may be used. By forming the insulating layer, deterioration of the light emitting element due to impurities such as water can be suppressed, which is preferable.

[0339] The sealing layer 1029 may be any one or two, or may be four or more sealing layers. By forming the sealing layer in multiple layers, impurities such as water can be prevented from entering the display device from the outside. This is preferable because it can effectively prevent the particles from penetrating into the inside of the display device. In the case of a multi-layer structure, a preferable structure is one in which a resin and an inorganic material are laminated.

[0340] The sealing substrate 1031 may have any function as long as it has a function of protecting the light-emitting element. Therefore, a flexible substrate or film can be used for the sealing substrate 1031.

[0341] Note that the configuration shown in this embodiment may be appropriately combined with other embodiments or other configurations in this embodiment. Combinations are possible.

[0342] (Embodiment 5) In this embodiment, a display device including a light-emitting element of one embodiment of the present invention will be described with reference to FIGS. The explanation will be given with reference to FIG.

[0343] Note that FIG. 18A is a block diagram illustrating a display device of one embodiment of the present invention, and 8(B) is a circuit diagram illustrating a pixel circuit included in a display device of one embodiment of the present invention.

[0344] <Explanation about the display device> The display device shown in FIG. 18A has a region having pixels of a display element (hereinafter referred to as a pixel portion 802). ) and a circuit section ( hereinafter referred to as a drive circuit section 804), and a circuit having a function of protecting the element (hereinafter referred to as a protection circuit 80 6) and a terminal portion 807. Note that the protection circuit 806 is not provided in the configuration. That's fine.

[0345] A part or the whole of the driver circuit portion 804 is formed on the same substrate as the pixel portion 802. This makes it possible to reduce the number of parts and terminals. When a part or all of the driving circuit is not formed on the same substrate as the pixel portion 802, A part or the whole of the path portion 804 is COG or TAB (Tape Automated Bearing). It can be implemented by

[0346] The pixel section 802 is arranged in X rows (X is a natural number of 2 or more) and Y columns (Y is a natural number of 2 or more). The display device has a circuit for driving a plurality of display elements (hereinafter referred to as pixel circuit 801), The path portion 804 is a circuit for outputting a signal (scanning signal) for selecting a pixel (hereinafter referred to as a scanning line driving circuit 804a), for supplying signals (data signals) for driving the display elements of the pixels. The signal line driver circuit 804b includes a driver circuit such as the circuit (hereinafter referred to as a signal line driver circuit 804b).

[0347] The scanning line driver circuit 804a includes a shift register and the like. A signal for driving the shift register is inputted through the terminal portion 807, and a signal is outputted. For example, a start pulse signal, a clock signal, etc. are input to the scanning line driver circuit 804a. The scanning line driving circuit 804a is connected to the wiring to which the scanning signal is applied (hereinafter referred to as the wiring). The scanning lines GL_1 to GL_X are connected to the gate electrode GL_1. A plurality of driving circuits 804a are provided, and the scanning lines GL_1 to GL_3 are driven by the plurality of scanning line driving circuits 804a. Alternatively, the scanning line driving circuit 804a may control the GL_X by dividing it. However, the present invention is not limited to this, and the scanning line driving circuit 80 4a may also provide other signals.

[0348] The signal line driver circuit 804b includes a shift register and the like. Through the terminal portion 807, signals for driving the shift register as well as the source of the data signal are transmitted. The signal line driver circuit 804b receives the image signal and drives the pixel circuit The signal line driver circuit 804b has a function of generating a data signal to be written to the signal line driver circuit 804b. A data signal is generated in accordance with a pulse signal obtained by inputting a start pulse, a clock signal, etc. The signal line driver circuit 804b has a function of controlling the output of a signal. The data lines DL_1 to DL_Y are connected to the data lines DL_2 through DL_Y. Alternatively, the signal line driver circuit 804b may have a function of supplying an initialization signal. However, the present invention is not limited to this, and the signal line driver circuit 804b may also supply other signals. It is possible.

[0349] The signal line driver circuit 804b is configured using, for example, a plurality of analog switches. The signal line driver circuit 804b sequentially turns on a plurality of analog switches, The image signal can be time-divided and output as a data signal. The signal line driver circuit 804b may be configured using the same.

[0350] Each of the plurality of pixel circuits 801 is connected to one of the plurality of scanning lines GL to which a scanning signal is applied. A pulse signal is input via the data line DL, and a data signal is given via one of the data lines DL. Each of the pixel circuits 801 receives a data signal via a scanning line driving circuit. 804a controls the writing and holding of data of the data signal. The second pixel circuit 801 is connected to the scanning line driving circuit GL_m (m is a natural number equal to or less than X) via the scanning line GL_m. A pulse signal is input from 804a, and the potential of the data line DL_n ( A data signal is input from the signal line driver circuit 804b via the signal line driver circuit 804b (n is a natural number equal to or less than Y).

[0351] The protection circuit 806 shown in FIG. 18A is, for example, a protection circuit including a scanning line driver circuit 804a and a pixel circuit 8 01. Alternatively, the protection circuit 806 is connected to the scanning line GL, which is the wiring between the signal line driver The data line DL is connected between the circuit 804b and the pixel circuit 801. The protection circuit 806 can be connected to the wiring between the scanning line driving circuit 804a and the terminal portion 807. Alternatively, the protection circuit 806 may be formed on the wiring between the signal line driver circuit 804b and the terminal portion 807. The terminal portion 807 can be connected to a power supply and a line from an external circuit to the display device. This refers to the part where terminals for inputting control signals and image signals are provided.

[0352] When a potential outside a certain range is applied to the wiring to which the protection circuit 806 is connected, the protection circuit 806 This is a circuit that brings one wire into electrical continuity with another wire.

[0353] As shown in FIG. 18A, a pixel section 802 and a driver circuit section 804 are provided with a protection circuit 80. 6, ESD (Electro Static Discharge: This can improve the resistance of the display device to overcurrents caused by electrostatic discharges and the like. However, the configuration of the protection circuit 806 is not limited to this. For example, A configuration in which a protection circuit 806 is connected, or a configuration in which the protection circuit 806 is connected to the signal line driver circuit 804b Alternatively, a configuration in which a protection circuit 806 is connected to the terminal portion 807 may be used. It can also be done as follows.

[0354] In FIG. 18A, the scanning line driver circuit 804a and the signal line driver circuit 804b Therefore, although an example in which the driver circuit portion 804 is formed is shown, the present invention is not limited to this configuration. For example, only the scanning line driver circuit 804a is formed, and a signal line driver circuit prepared separately is formed. A substrate (for example, a drive circuit board formed of a single crystal semiconductor film or a polycrystalline semiconductor film) is mounted. It may also be configured as follows.

[0355] <Pixel circuit configuration example> The plurality of pixel circuits 801 shown in FIG. 18(A) may have the configuration shown in FIG. 18(B), for example. It is possible.

[0356] The pixel circuit 801 shown in FIG. 18B includes transistors 852 and 854 and a capacitor 86 2 and a light-emitting element 872.

[0357] One of the source electrode and the drain electrode of the transistor 852 is supplied with a data signal. The gate of the transistor 852 is electrically connected to the wiring (data line DL_n). The electrodes are electrically connected to wiring (scanning lines GL_m) to which gate signals are applied.

[0358] The transistor 852 has a function of controlling writing of data signals.

[0359] One of the pair of electrodes of the capacitor 862 is connected to a wiring to which a potential is applied (hereinafter, a potential supply line VL _a), and the other is electrically connected to the source electrode and drain electrode of transistor 852. The second electrode is electrically connected to the other of the first and second electrodes.

[0360] The capacitor 862 functions as a storage capacitor for holding written data.

[0361] One of the source electrode and the drain electrode of the transistor 854 is connected to the potential supply line VL_a. Furthermore, the gate electrode of transistor 854 is electrically connected to the It is electrically connected to the other of the source electrode and the drain electrode.

[0362] One of the anode and cathode of the light emitting element 872 is electrically connected to the potential supply line VL_b. The other is electrically connected to the other of the source electrode and drain electrode of the transistor 854. will be done.

[0363] The light-emitting element 872 may be any of the light-emitting elements described in any of Embodiments 1 to 3. can be done.

[0364] A high power supply potential VDD is applied to one of the potential supply lines VL_a and VL_b. and the other is supplied with a low power supply potential VSS.

[0365] In a display device having the pixel circuit 801 of FIG. 18(B), for example, The scanning line driving circuit 804a sequentially selects the pixel circuits 801 in each row, and turns on the transistors 852. The data signal is written by turning it on.

[0366] The pixel circuit 801 in which data has been written is turned off by turning off the transistor 852. Furthermore, the potential of the transistor 854 changes depending on the potential of the written data signal. The amount of current flowing between the source electrode and the drain electrode is controlled, and the light emitting element 872 The light is emitted at a brightness that corresponds to the flow rate. By repeating this process row by row, an image can be displayed.

[0367] In addition, the pixel circuit has a function to correct the influence of fluctuations in the threshold voltage of the transistor, etc. 19(A)(B) and 20(A)(B) show examples of pixel circuits.

[0368] The pixel circuit shown in FIG. 19A includes six transistors (transistors 303_1 to 303_3). 19A, the semiconductor device 100 includes a capacitor 304 and a light-emitting element 305. The pixel circuit shown in FIG. 1 includes wirings 301_1 to 301_5, a wiring 302_1, and a wiring 30 2_2 are electrically connected. For example, a P-channel transistor can be used.

[0369] The pixel circuit shown in FIG. 19B is the pixel circuit shown in FIG. 19A, except that a transistor 303 19B, the pixel circuit shown in FIG. 19B is configured to include wiring 301_6 and The wiring 301_5 and the wiring 301_6 are electrically connected. may be electrically connected to each other. For example, a P-channel transistor can be used.

[0370] The pixel circuit shown in FIG. 20A includes six transistors (transistors 308_1 to 308_3). 308_6), a capacitor 304, and a light-emitting element 305. The pixel circuit shown in FIG. Here, the wiring 306_1 and the wiring 306_3 are electrically connected. The transistors 308_1 to 308_6 may be electrically connected. For example, a P-channel transistor can be used.

[0371] The pixel circuit shown in FIG. 20B includes two transistors (transistor 309_1 and transistor 309_2). transistor 309_2) and two capacitance elements (capacitance element 304_1 and capacitance element 304_ 2) and a light-emitting element 305. In addition, the pixel circuit shown in FIG. The wirings 11_1 to 311_3, the wiring 312_1, and the wiring 312_2 are electrically connected to each other. In addition, by configuring the pixel circuit as shown in FIG. 20(B), for example, The transistor 309 can be a current-driven type (also called a CVCC type). For example, a P-channel transistor can be used for the transistors 1 and 309_2. .

[0372] Furthermore, the light-emitting element of one embodiment of the present invention may be an active matrix light-emitting element having an active element in a pixel of a display device. The display device is a passive matrix type that does not have active elements in the pixels. It can be applied to each method.

[0373] In the active matrix system, the active element (active element, nonlinear element) is a transistor. By using not only transistors but also various active elements (active elements, nonlinear elements), For example, MIM (Metal Insulator Metal) or T It is also possible to use FD (Thin Film Diode) and other elements. Since the number of manufacturing steps is small, it is possible to reduce manufacturing costs and improve yields. Alternatively, these elements can improve the aperture ratio due to their small size. This makes it possible to achieve low power consumption and high brightness.

[0374] Other than the active matrix type, active elements (active elements, nonlinear elements) It is also possible to use a passive matrix type that does not use active elements (active elements). Since it does not use any nonlinear elements, there are fewer manufacturing steps, which reduces manufacturing costs and improves yield. Alternatively, active elements (active elements, non-linear elements) can be used. Since the aperture ratio is not increased, it is possible to achieve low power consumption or high brightness. This can be done.

[0375] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. can be done.

[0376] (Embodiment 6) In this embodiment, a display device including a light-emitting element of one embodiment of the present invention and a display device including the light-emitting element An electronic device having an input device attached thereto will be described with reference to FIGS. 21 to 25. FIG.

[0377] <Touch panel explanation 1> In the present embodiment, an example of an electronic device is a device that combines a display device and an input device. The touch panel 2000 will be described. The case where the .sigma.sub.2 is included will be described.

[0378] 21(A) and 21(B) are perspective views of the touch panel 2000. In B), representative components of touch panel 2000 are shown for clarity.

[0379] The touch panel 2000 includes a display device 2501 and a touch sensor 2595 (see FIG. 2). 1(B)). The touch panel 2000 includes a substrate 2510, a substrate 2570, and a substrate The substrate 2510, the substrate 2570, and the substrate 2590 are all However, any one of the substrates 2510, 2570, and 2590 is flexible. Alternatively, one or all of the components may be configured to be non-flexible.

[0380] The display device 2501 has a plurality of pixels on a substrate 2510 and a display device that can supply signals to the pixels. The plurality of wirings 2511 are arranged around the periphery of the substrate 2510. The wire is routed through a cable, part of which forms the terminal 2519. The terminal 2519 is an FPC2509 (1). In addition, the plurality of wirings 2511 are electrically connected to the signal line driver circuit 2503s ( The signal from 1) can be fed to multiple pixels.

[0381] The substrate 2590 is electrically connected to the touch sensor 2595. The plurality of wirings 2598 are routed around the periphery of the substrate 2590. The terminals are connected to the FPC 25 via a connection layer 2599. 21(B), for clarity, the substrate 2590 is electrically connected to the substrate 2590. The electrodes and wiring of the touch sensor 2595 are provided on the back side (the surface facing the substrate 2510). Lines are shown as solid lines.

[0382] As the touch sensor 2595, for example, a capacitance type touch sensor can be applied. The capacitive type includes a surface type electrostatic capacitance type and a projected type electrostatic capacitance type.

[0383] The projected capacitive type is mainly divided into self-capacitance type and mutual capacitance type, which differ mainly in the driving method. The mutual capacitance method is preferable because it allows simultaneous multi-point detection.

[0384] The touch sensor 2595 shown in FIG. 21(B) is a projected capacitive touch sensor. This is a configuration in which the

[0385] The touch sensor 2595 can detect the proximity or contact of a detection object such as a finger. Various sensors can be applied.

[0386] The projected capacitive touch sensor 2595 has an electrode 2591 and an electrode 2592. The electrode 2591 is electrically connected to one of the plurality of wirings 2598, and the electrode 2592 is It is electrically connected to any other of the plurality of wirings 2598.

[0387] As shown in FIGS. 21(A) and 21(B), the electrodes 2592 are made of a plurality of electrodes repeatedly arranged in one direction. The shape is such that the quadrilaterals are connected at their corners.

[0388] The electrode 2591 is quadrilateral and is repeated in a direction intersecting the direction in which the electrode 2592 extends. are placed.

[0389] The wiring 2594 is electrically connected to the two electrodes 2591 that sandwich the electrode 2592. In this case, it is preferable to form the electrode 2592 and the wiring 2594 so that the area of ​​the intersection is as small as possible. This reduces the area where no electrodes are provided, reducing variations in transmittance. As a result, the variation in brightness of light passing through the touch sensor 2595 can be reduced. can be done.

[0390] The shapes of the electrodes 2591 and 2592 are not limited to this, and may take various shapes. For example, multiple electrodes 2591 are arranged with as few gaps as possible, and A plurality of electrodes 2592 are provided at intervals so that there is an area where they do not overlap with the electrodes 2591. In this case, a wire may be provided between two adjacent electrodes 2592, which is electrically isolated from these. Providing an insulated dummy electrode is preferable because it can reduce the area of ​​the region with different transmittance. .

[0391] <Explanation about the display device> Next, the display device 2501 will be described in detail with reference to FIG. ) corresponds to a cross-sectional view taken along the dashed dotted line X1-X2 shown in FIG. 21(B).

[0392] The display device 2501 has a plurality of pixels arranged in a matrix. and a pixel circuit for driving the display element.

[0393] In the following description, a light emitting element that emits white light is applied to a display element. However, the display element is not limited to this. For example, To achieve different colors, light emitting elements with different luminescent colors may be applied.

[0394] The substrate 2510 and the substrate 2570 may have a water vapor permeability of, for example, 1×10 -5 g· m -2 ·day -1 Less than 1 × 10 -6 g·m -2 ·day -1 It is possible that A flexible material can be preferably used. Alternatively, the thermal expansion coefficient of the substrate 2510 and the It is preferable to use a material whose coefficient of thermal expansion is approximately equal to that of the plate 2570. For example, is 1×10 -3 / K or less, preferably 5×10 -5 / K or less, more preferably 1×10 - 5 A material having a solubility of 0.1 kJ / K or less can be suitably used.

[0395] The substrate 2510 has an insulating layer 2510a that prevents impurities from diffusing into the light-emitting element, and a flexible The substrate 2510b and the adhesive layer 2 that bonds the insulating layer 2510a and the flexible substrate 2510b together. The substrate 2570 is a laminate having a layer 510c and a layer 510d. and a flexible substrate 2570b. 2570b and an adhesive layer 2570c that bonds them together.

[0396] The adhesive layer 2510c and the adhesive layer 2570c may be made of, for example, polyester or polyolefin. Polyimide, polycarbonate or acrylic Polyurethane resin, epoxy resin, or silicone resin can be used. Any material containing a resin having a siloxane bond can be used.

[0397] In addition, a sealing layer 2560 is provided between the substrate 2510 and the substrate 2570. It is preferable that the refractive index of the sealing material is larger than that of air. When light is extracted from the layer 2560 side, the sealing layer 2560 can also serve as an optical bonding layer. Cut.

[0398] A sealant may be formed on the outer periphery of the sealing layer 2560. As a result, the area surrounded by the substrate 2510, the substrate 2570, the sealing layer 2560, and the sealant The sealing layer 2560 may have a light emitting element 2550R. An inert gas (nitrogen, argon, etc.) may be filled. In addition, a desiccant may be added to the inert gas. Alternatively, a resin such as acrylic or epoxy may be used. The sealing material may be, for example, an epoxy resin or It is preferable to use glass frit. In addition, the material used for the sealing material is one that is resistant to moisture and acid. It is preferable to use a material that is opaque to the element.

[0399] The display device 2501 also has a pixel 2502R. The pixel 2502R is a light-emitting model. It has a Joule 2580R.

[0400] The pixel 2502R includes a light emitting element 2550R and a power supply for the light emitting element 2550R. The transistor 2502t is a transistor that can The light emitting module 2580R includes a light emitting element 2550R and It has a colored layer 2567R.

[0401] The light emitting element 2550R includes a lower electrode, an upper electrode, and an EL layer between the lower electrode and the upper electrode. The light-emitting element 2550R may be, for example, any of the light-emitting elements described in Embodiments 1 to 3. Optical elements can be applied.

[0402] In addition, a microcavity structure is adopted between the lower electrode and the upper electrode, and at a specific wavelength, The light intensity may be increased.

[0403] Furthermore, when the sealing layer 2560 is provided on the side from which light is extracted, the sealing layer 2560 It contacts the optical element 2550R and the colored layer 2567R.

[0404] The colored layer 2567R is located so as to overlap the light emitting element 2550R. A part of the light emitted by 2550R passes through the colored layer 2567R and is emitted in the direction of the arrow shown in the figure. The light is emitted to the outside of the optical module 2580R.

[0405] Furthermore, the display device 2501 is provided with a light-shielding layer 2567BM in the light-emitting direction. The light-shielding layer 2567BM is provided so as to surround the colored layer 2567R.

[0406] The colored layer 2567R only needs to have a function of transmitting light in a specific wavelength range. For example, a color filter that transmits light in the red wavelength region, a color filter that transmits light in the green wavelength region, Color filters that transmit light in the blue wavelength range and light in the yellow wavelength range. A transparent color filter can be used. Each color filter is made of various materials. The method includes printing, inkjet printing, and etching using photolithography technology. It can be formed by.

[0407] The display device 2501 is also provided with an insulating layer 2521. The insulating layer 2521 is formed to flatten the unevenness caused by the pixel circuit. In addition, the insulating layer 2521 has a function of suppressing diffusion of impurities. This prevents the reliability of the transistor 2502t and the like from being reduced due to the diffusion of impurities. It can be suppressed.

[0408] The light emitting element 2550R is formed above the insulating layer 2521. The lower electrode of 550R is provided with a partition wall 2528 that overlaps the edge of the lower electrode. A spacer for controlling the distance between the substrate 2510 and the substrate 2570 is provided on the partition wall 2528. It may be formed.

[0409] The scanning line driver circuit 2503g(1) includes a transistor 2503t and a capacitor 2503c. The driver circuit and the pixel circuit can be formed on the same substrate in the same process. do.

[0410] Moreover, wiring 2511 capable of supplying signals is provided on the substrate 2510 . A terminal 2519 is provided on the wiring 2511. The terminal 2519 is also provided with an FP C2509(1) is electrically connected. FPC2509(1) also transmits video signals, It has the function of supplying clock signals, start signals, reset signals, etc. 509(1) may have a printed wiring board (PWB) attached.

[0411] In addition, transistors with various structures can be applied to the display device 2501. In 22(A), an example is given of a case where a bottom gate type transistor is applied. However, the present invention is not limited to this, and for example, a top gate type transistor shown in FIG. The display device 2501 may be configured to use the same.

[0412] In addition, there is no particular limitation on the polarity of the transistor 2502t and the transistor 2503t. There is no fixed definition, and the structure has N-channel and P-channel transistors. A structure consisting of either a P-channel transistor or a P-channel transistor is used. In addition, the crystal structure of the semiconductor film used in the transistors 2502t and 2503t may be For example, an amorphous semiconductor film or a crystalline semiconductor film can be used. In addition, semiconductor materials include semiconductors of group 14 (for example, semiconductors containing silicon). A compound semiconductor (including an oxide semiconductor), an organic semiconductor, etc. can be used. Either or both of the transistors 2502t and 2503t are provided with an energy Oxides with a gap of 2 eV or more, preferably 2.5 eV or more, and more preferably 3 eV or more The use of a semiconductor is preferable because the off-state current of the transistor can be reduced. The oxide semiconductor includes In-Ga oxide, In-M-Zn oxide (M is Al, G a, Y, Zr, La, Ce, Sn, Hf, or Nd).

[0413] <Explanation about touch sensors> Next, the touch sensor 2595 will be described in detail with reference to FIG. (C) corresponds to a cross-sectional view taken along the dashed dotted line X3-X4 shown in FIG. 21(B).

[0414] The touch sensor 2595 is made up of electrodes 2591 and electrodes 2592 arranged in a staggered pattern on a substrate 2590. 2592, an insulating layer 2593 covering the electrodes 2591 and 2592, and the adjacent electrodes 25 91 and a wiring 2594 that electrically connects them.

[0415] The electrode 2591 and the electrode 2592 are formed using a light-transmitting conductive material. Examples of conductive materials having the formula include indium oxide, indium tin oxide, and indium zinc oxide. Conductive oxides such as zinc oxide, zinc oxide, and zinc oxide doped with gallium can be used. A film containing graphene may also be used. The film containing graphene may be, for example, a film-like The graphene oxide film can be formed by reducing the graphene oxide film formed on the substrate. For example, a method of applying heat can be mentioned.

[0416] For example, a film of a light-transmitting conductive material is formed on the substrate 2590 by sputtering. After that, various patterning techniques such as photolithography are used to remove unnecessary parts. , an electrode 2591 and an electrode 2592 can be formed.

[0417] The insulating layer 2593 may be made of a resin such as acrylic or epoxy. In addition to resins with siloxane bonds, silicon oxide, silicon oxynitride, aluminum oxide, Inorganic insulating materials such as rubber can also be used.

[0418] An opening reaching the electrode 2591 is provided in the insulating layer 2593, and a wiring 2594 is adjacent to the opening. The transparent conductive material is used to increase the aperture ratio of the touch panel. Therefore, it can be suitably used for the wiring 2594. A material having higher conductivity than the electrode 2592 is preferable for the wiring 2594 because it can reduce electrical resistance. It can be used appropriately.

[0419] The electrodes 2592 extend in one direction, and a plurality of electrodes 2592 are provided in a stripe pattern. Moreover, the wiring 2594 is provided so as to intersect with the electrode 2592.

[0420] A pair of electrodes 2591 is provided with one electrode 2592 sandwiched therebetween. A pair of electrodes 2591 are electrically connected.

[0421] The plurality of electrodes 2591 are arranged in a direction that is not necessarily perpendicular to one electrode 2592. The angle does not have to be 0 degrees, and may be greater than 0 degrees and less than 90 degrees.

[0422] The wiring 2598 is electrically connected to the electrode 2591 or the electrode 2592. A part of the wiring 2598 functions as a terminal. The wiring 2598 is made of, for example, aluminum. Aluminum, gold, platinum, silver, nickel, titanium, tungsten, chromium, molybdenum, iron, Use of metal materials such as ballast, copper, or palladium, or alloy materials containing such metal materials. can be done.

[0423] An insulating layer covering the insulating layer 2593 and the wiring 2594 is provided, and the touch sensor 2595 may be protected.

[0424] The connection layer 2599 electrically connects the wiring 2598 and the FPC 2509(2). .

[0425] The connection layer 2599 is made of an anisotropic conductive film (ACF). conductive film) and anisotropic conductive paste (ACP) Conductive Paste) can be used.

[0426] <Touch panel explanation 2> Next, details of the touch panel 2000 will be described with reference to FIG. 21A corresponds to a cross-sectional view taken along the dashed line X5-X6 shown in FIG.

[0427] The touch panel 2000 shown in FIG. 23A is the same as the display device 250 described in FIG. 22A. 22(C) and the touch sensor 2595 described in FIG. 22(C).

[0428] The touch panel 2000 shown in FIG. 23(A) is similar to the touch panel 2000 shown in FIG. 22(A) and FIG. 22(C). In addition to the components described above, it has an adhesive layer 2597 and an anti-reflection layer 2567p.

[0429] The adhesive layer 2597 is provided in contact with the wiring 2594. The substrate 2590 is attached to the substrate 2570 so that the sensor 2595 overlaps the display device 2501. The adhesive layer 2597 is preferably transparent. The material 597 can be a thermosetting resin or an ultraviolet curing resin. For example, Acrylic resin, urethane resin, epoxy resin, or siloxane resin may be used. This can be done.

[0430] The anti-reflection layer 2567p is provided at a position overlapping the pixel. For example, a circular polarizing plate can be used.

[0431] Next, for a touch panel having a different configuration from that shown in FIG. 23(A), FIG. 23(B) This will be used to explain.

[0432] FIG. 23(B) is a cross-sectional view of the touch panel 2001. The panel 2001 is a touch panel 2000 shown in FIG. 23(A) and a display device 2501. The location of the touch sensor 2595 is different. Here, the different configurations are explained in detail. The description of the touch panel 2000 is cited for the parts where a similar configuration can be used.

[0433] The colored layer 2567R is located so as to overlap the light emitting element 2550R. The light-emitting element 2550R emits light toward the side where the transistor 2502t is provided. As a result, a part of the light emitted by the light emitting element 2550R passes through the colored layer 2567R, The light is emitted to the outside of light emitting module 2580R in the direction of the arrow shown in the figure.

[0434] The touch sensor 2595 is provided on the substrate 2510 side of the display device 2501. .

[0435] The adhesive layer 2597 is between the substrate 2510 and the substrate 2590 and is in contact with the display device 2501. Stick the Chisensor 2595 together.

[0436] As shown in FIGS. 23A and 23B, the light emitted from the light emitting element is guided by the substrate 2510 and the substrate 2511. It may be injected through either or both of the plates 2570 .

[0437] <Explanation of how to drive the touch panel> Next, an example of a method for driving a touch panel will be explained with reference to FIGS. 24(A) and 24(B). cormorant.

[0438] FIG. 24A is a block diagram showing the configuration of a mutual capacitance type touch sensor. In (A), a pulse voltage output circuit 2601 and a current detection circuit 2602 are shown. In FIG. 24(A), the electrodes 2621 to which the pulse voltage is applied are designated as X1-X6, and the change in current The electrodes 2622 for detecting the change are shown as Y1-Y6, each with six wires. In addition, FIG. 24(A) shows a capacitance formed by overlapping an electrode 2621 and an electrode 2622. 2603. The electrodes 2621 and 2622 are interchangeable in function. It may be possible.

[0439] The pulse voltage output circuit 2601 is a circuit for applying pulses to the X1-X6 wirings in sequence. When a pulse voltage is applied to the wiring of X1-X6, the voltage that forms the capacitance 2603 An electric field is generated between the electrodes 2621 and 2622. The electric field generated between the electrodes is By using the change in the mutual capacitance of the capacitance 2603, the proximity of the object to be detected or A contact can be detected.

[0440] The current detection circuit 2602 detects the change in the mutual capacitance of the capacitor 2603 between the wires Y1 and Y6. This is a circuit for detecting changes in current. The wiring of Y1-Y6 detects the proximity of the object to be detected, Or, if there is no contact, the detected current value will not change, but the proximity of the object to be detected, or When the mutual capacitance decreases due to contact, a decrease in the current value is detected. The detection may be performed using an integrating circuit or the like.

[0441] Next, FIG. 24(B) shows the input voltage of the mutual capacitance type touch sensor shown in FIG. 24(A). The timing chart of the output waveform is shown in FIG. 24(B). In FIG. 24(B), when no object is detected (non-touched), The two cases shown are when the object is detected (touch) and when the object is detected (touch). (B) shows the waveform of the voltage value corresponding to the current value detected in the wires Y1-Y6. .

[0442] A pulse voltage is applied to the wires X1-X6 in order, and the The waveform in the Y6 wiring changes. When there is no proximity or contact of the object to be detected, X1-X6 The waveforms of Y1-Y6 change uniformly according to the change in the voltage of the wiring. Or, at the contact point, the current value decreases, and the corresponding voltage waveform also changes. do.

[0443] In this way, by detecting the change in mutual capacitance, the proximity or contact of the object to be detected can be detected. It is possible.

[0444] <Sensor circuit explanation> In addition, in FIG. 24A, only a capacitor 2603 is provided at the intersection of the wiring as a touch sensor. The configuration of a passive matrix touch sensor is shown, but it has a transistor and a capacitor. An active matrix touch sensor may be used. An example of a sensor circuit included in the sensor is shown in FIG.

[0445] The sensor circuit shown in FIG. 25 includes a capacitor 2603, a transistor 2611, and a transistor 2612 and a transistor 2613.

[0446] A signal G2 is applied to the gate of the transistor 2613, and a signal G3 is applied to either the source or the drain of the transistor 2613. A voltage VRES is applied, and the other is connected to one electrode of the capacitor 2603 and the transistor 2611 The transistor 2611 has a source and a drain electrically connected to the gate of the transistor 2611. The source or drain of the transistor 2612 is electrically connected to the voltage VS The transistor 2612 receives a signal G1 at its gate and a signal S at its source or The other electrode of the drain is electrically connected to the wiring ML. The other electrode of the capacitor 2603 is connected to a voltage VS S is given.

[0447] Next, the operation of the sensor circuit shown in Fig. 25 will be described. First, the signal G2 is When a potential is applied to turn on the transistor 2613, the gate of the transistor 2611 is turned on. A potential corresponding to the voltage VRES is applied to the node n to which the signal G2 is connected. When a potential that turns off the transistor 2613 is applied, the potential of the node n Retained.

[0448] Next, the mutual capacitance of the capacitor 2603 changes when a detection object such as a finger approaches or touches the sensor. As a result, the potential of the node n changes from VRES.

[0449] The read operation applies a potential to the signal G1 that turns on the transistor 2612. The current flowing through the transistor 2611 in accordance with the potential of the node n, that is, the current flowing through the wiring ML By detecting this current, the proximity or contact of the object to be detected can be detected. This can be done.

[0450] The transistors 2611, 2612, and 2613 include: It is preferable to use an oxide semiconductor layer as the semiconductor layer in which the channel region is formed. By applying such a transistor to the transistor 2613, the potential of the node n This allows the voltage to be held for a long period of time, and the operation of re-supplying VRES to node n (restart) is performed. This can reduce the frequency of refresh operations.

[0451] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. can be done.

[0452] (Embodiment 7) In this embodiment, a display module and an electronic device including a light-emitting element of one embodiment of the present invention will be described. This will be explained with reference to FIGS. 26 to 29.

[0453] <Explanation about the display module> The display module 8000 shown in FIG. 26 includes an upper cover 8001 and a lower cover 8002. Between them, the touch sensor 8004 connected to FPC8003 and the touch sensor 8005 connected to FPC8006 are A display device 8006, a frame 8009, a printed circuit board 8010, and a battery 8011 are included. do.

[0454] The light-emitting element of one embodiment of the present invention can be used for the display device 8006, for example.

[0455] The upper cover 8001 and the lower cover 8002 are connected to the touch sensor 8004 and the display device 8005. The shape and dimensions can be changed appropriately to match the size of 006.

[0456] The touch sensor 8004 is a resistive or capacitive touch sensor mounted on the display device 8 8006. In addition, the opposing substrate (sealing substrate) of the display device 8006 It is also possible to provide a touch sensor function to the display device 8006. It is also possible to provide an optical sensor in each pixel to form an optical touch sensor.

[0457] The frame 8009 has a function of protecting the display device 8006 and also a function of preventing the operation of the printed circuit board 8010. It also functions as an electromagnetic shield to block electromagnetic waves generated by the frame. The frame 8009 may also function as a heat sink.

[0458] The printed circuit board 8010 includes a power supply circuit, a signal circuit for outputting a video signal and a clock signal. The power supply circuit is provided with a signal processing circuit. Alternatively, the power source may be a battery 8011 provided separately. This can be omitted if a commercial power source is used.

[0459] In addition, the display module 8000 includes components such as a polarizing plate, a retardation plate, and a prism sheet. It may also be provided in addition.

[0460] <Electronic device instructions> 27(A) to 27(G) are diagrams showing electronic devices. These electronic devices are A body 9000, a display unit 9001, a speaker 9003, operation keys 9005 (power switch, includes an operation switch), a connection terminal 9006, a sensor 9007 (force, displacement, position, speed, Acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electricity Measures field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared 9008, etc. Also, the sensor 900 The sensor 7 may have a function of measuring biological information such as a pulse sensor or a fingerprint sensor.

[0461] The electronic devices shown in FIGS. 27A to 27G can have various functions. For example, functions to display various information (still images, videos, text images, etc.) on the display, Sensor function, calendar, date or time display function, various software ( It has the function of controlling processing by using a program, wireless communication function, and various functions using wireless communication function. Functions for connecting to computer networks, transmitting various data using wireless communication functions, or receiving the program or data recorded on the recording medium, and It is to be noted that the functions shown in FIGS. 27(A) to 27(G) can be implemented. The functions that the electronic device shown in the figure can have are not limited to these, and it may have various functions. Although not shown in FIGS. 27(A) to 27(G), the electronic device may include: The electronic device may have a plurality of display units. The function to take pictures, take videos, and save the images to a recording medium (external or built-in to the camera) ) and a function to display the captured image on the display unit.

[0462] The electronic devices shown in FIGS. 27A to 27G will be described in detail below.

[0463] FIG. 27A is a perspective view showing a mobile information terminal 9100. The display portion 9001 is flexible. The display unit 9001 can be incorporated along the screen. It is equipped with a touch panel, and can be operated by touching the screen with a finger or a stylus. By touching the icon displayed on the display 9001, the application can be started. It is possible.

[0464] FIG. 27(B) is a perspective view showing the portable information terminal 9101. The portable information terminal 9101 has one or more functions selected from, for example, a telephone, a notebook, an information browsing device, etc. Specifically, it can be used as a smartphone. Note that the portable information terminal 9101 is shown in the figure with the speaker 9003, the connection terminal 9006, the sensor 9007, etc. omitted, but can be provided at the same position as the portable information terminal 9100 shown in FIG. 27(A). Also, the portable information terminal 9101 can display character and image information on its plurality of surfaces. For example, three operation buttons 9050 (also referred to as operation icons or simply icons) can be displayed on one surface of the display unit 900 1. Also, information 9051 indicated by a dashed rectangle can be displayed on another surface of the display unit 90 01. As an example of the information 9051, there are displays notifying incoming calls such as e-mails and SNS (Social Networking Service) and telephone calls, the subject of e-mails and SNS, the sender name of e-mails and SNS, the date and time, the remaining battery level, the antenna reception strength, etc. Alternatively, operation buttons 9050 etc. may be displayed at the position where the information 9051 is displayed, instead of the information 9051.

[0465] FIG. 27(C) is a perspective view showing the portable information terminal 9102. The portable information terminal 9102 has a function of displaying information on three or more surfaces of the display unit 9001. Here, an example is shown where the information 9052, the information 9053, and the information 9054 are displayed on different surfaces respectively. For example, the user of the portable information terminal 9102 stores the portable information terminal 9102 in the breast pocket of the suit, and In this state, the display (information 9053 in this case) can be confirmed. The telephone number or name of the caller is displayed in a position that can be observed from above the mobile information terminal 9102. The user can view the display without taking the mobile information terminal 9102 out of his pocket. You can check the call and decide whether to accept it or not.

[0466] 27(D) is a perspective view showing a wristwatch-type mobile information terminal 9200. The 9200 is suitable for mobile phone calls, e-mail, document browsing and writing, music playback, and internet communications. It is possible to run various applications such as computer games. The display surface of the display unit 9001 is curved, and the display is performed along the curved display surface. In addition, the portable information terminal 9200 can perform short-distance wireless communication according to a communication standard. For example, by communicating with a wireless headset, handset The mobile information terminal 9200 also has a connection terminal 9006. It has a connector and can directly exchange data with other information terminals. Charging can also be performed via the connection terminal 9006. It may also be possible to supply power wirelessly without going through 6.

[0467] 27(E), (F), and (G) are perspective views showing a foldable portable information terminal 9201. FIG. 27(E) is a perspective view of the portable information terminal 9201 in an unfolded state, and FIG. (F) shows the mobile information terminal 9201 being changed from one of the unfolded state and the folded state to the other. 27(G) is a perspective view of the portable information terminal 9201 in a folded state. The portable information terminal 9201 is highly portable when folded, and is easily portable when unfolded. When the display is turned on, the seamless, wide display area provides excellent visibility of the display. The display unit 9001 of the display device 01 is made up of three housings 9000 connected by hinges 9055. The two housings 9000 are supported by the hinge 9055. This allows the portable information terminal 9201 to be reversibly transformed from an unfolded state to a folded state. For example, the portable information terminal 9201 can be bent with a radius of curvature of 1 mm or more and 150 mm or less. It can be done.

[0468] Furthermore, examples of electronic devices include television sets (televisions or television receivers) (also called "computer"), computer monitors, digital cameras, digital video cameras, Digital photo frames, mobile phones (also called mobile phones or mobile phone devices), goggle-type Displays (head-mounted displays), portable game consoles, portable information terminals, audio playback Examples include live video equipment, large gaming machines such as pachinko machines, etc.

[0469] FIG. 28A shows an example of a television device. The television device 9300 includes a housing 9 9001 is built into the housing 9000. 000 is supported.

[0470] The television device 9300 shown in FIG. 28A is operated by an operation switch provided in the housing 9000. This can be done by a separate remote control 9311 or a switch. The display unit 9001 may be provided with a touch sensor, and the operation can be performed by touching the display unit 9001 with a finger or the like. The remote control operator 9311 may display information to be output from the remote control operator 9311. The remote control 9311 may have a display unit that displays the operation keys or touch panel. The panel allows you to operate the channel and volume, and the display unit 9001 You can manipulate the video.

[0471] The television device 9300 includes a receiver, a modem, and the like. It is possible to receive general television broadcasts by using a modem. By connecting to a communication network, it can be one-way (sender to receiver) or two-way. It is also possible to communicate information (between a sender and a receiver, or between receivers).

[0472] Furthermore, since the electronic device or lighting device of one embodiment of the present invention is flexible, it can be easily installed inside a house or a building. It can also be incorporated into walls or exterior walls, or along the curved surfaces of the interior or exterior of a vehicle. be.

[0473] Fig. 28(B) shows the exterior of the car 9700. Fig. 28(C) shows the driver's seat of the car 9700. The automobile 9700 includes a body 9701, wheels 9702, a dashboard 9703, a The display device or the light-emitting device of one embodiment of the present invention includes a light emitting element 9704 and the like. For example, the display portion 9710 to the display portion 9720 shown in FIG. The display device, the light-emitting device, or the like according to one embodiment of the present invention can be provided in the display portion 9715.

[0474] The display portion 9710 and the display portion 9711 are display devices provided on a windshield of an automobile. In a display device or a light-emitting device according to one embodiment of the present invention, electrodes and wirings are formed using a light-transmitting conductive material. By making it from a transparent material, the other side can be seen through, creating a so-called see-through state. If the display unit 9710 or the display unit 9711 is in a see-through state, the car 97 Therefore, the display device or the like according to one embodiment of the present invention does not obstruct the view even when the vehicle is driving. The light emitting device or the like can be installed on the windshield of the automobile 9700. When a transistor for driving a light-emitting device is provided, an organic semiconductor material is used. Transistors that have light-transmitting properties, such as organic transistors using a semiconductor or transistors using an oxide semiconductor, A transistor may be used.

[0475] The display unit 9712 is a display device provided in a pillar portion. By displaying the image from the imaging means on the display unit 9712, the view blocked by the pillars can be cleared. The display unit 9713 is a display device provided in the dashboard. For example, an image captured by an imaging means provided on the vehicle body is displayed on the display unit 9713. This allows the driver to supplement the view obstructed by the dashboard. By projecting images from the imaging means installed in the In addition, by projecting images that complement the invisible parts, it is possible to create a more natural and natural appearance. Safety can be checked without any sense of discomfort.

[0476] FIG. 28(D) shows the interior of a car with bench seats for the driver and passenger. The display unit 9721 is a display device provided in the door. By displaying an image from the imaging means on the display unit 9721, it is possible to The display portion 9722 is a display device provided on the handle. The display unit 9723 is a display device provided in the center of the seat surface of the bench seat. The display device is installed on the seat or backrest, and the heat generated by the display device is It can also be used as a seat heater using this as a heat source.

[0477] The display unit 9714, the display unit 9715, or the display unit 9722 displays navigation information, speech such as the odometer, tachometer, mileage, fuel level, gear status, and air conditioning settings. It is also possible to provide various other information. The above information can be changed as needed to suit the user's preferences. The images can also be displayed on the display units 9710 to 9713, the display unit 9721, and the display unit 9723. In addition, the display units 9710 to 9715 and the display units 9721 to 9723 are illuminated. The display units 9710 to 9715 can also be used as a lighting device. The portion 9721 to the display portion 9723 can also be used as a heating device.

[0478] Furthermore, the electronic device of one embodiment of the present invention may include a secondary battery and may perform contactless power transmission. It is preferable that the secondary battery can be charged using the power supply.

[0479] As the secondary battery, for example, a lithium polymer battery (lithium ion battery) using a gel electrolyte is used. Lithium-ion secondary batteries such as lithium-ion polymer batteries, lithium-ion batteries, nickel-metal hydride batteries batteries, nickel-cadmium batteries, organic radical batteries, lead-acid batteries, secondary air batteries, nickel-zinc batteries, silver-zinc batteries Examples include lead batteries.

[0480] The electronic device according to one embodiment of the present invention may include an antenna. By using the battery, it is possible to display images, information, etc. on the display unit. , the antenna may be used for contactless power transfer.

[0481] The display device 9500 shown in FIGS. 29(A) and 29(B) includes a plurality of display panels 9501 and a shaft portion 9 511 and a bearing portion 9512. The plurality of display panels 9501 have a display area 9502 and a light-transmitting region 9503.

[0482] The display panels 9501 are flexible. The filters 9501 are arranged so that they partially overlap each other. The light-transmitting region 9503 of the display panel 9501 can be overlapped. By using the display panel 9501, a large screen display device can be provided. The display panel 9501 can be rolled up depending on the situation, making it a versatile display. It can be a display device.

[0483] 29(A) and 29(B), the display area 9502 is located on the adjacent display panel 950. 1 shows a state in which the display panels are spaced apart, but this is not limited to this. For example, the display panels 9 By overlapping the display areas 9502 of the 501 without any gaps, a continuous display area 9502 is created. You may do so.

[0484] The electronic device described in this embodiment has a display unit for displaying some information. However, the light-emitting element of one embodiment of the present invention can also be applied to electronic devices that do not have a display portion. In addition, the display unit of the electronic device described in this embodiment has flexibility. and a configuration in which the display can be performed along a curved display surface, or a foldable display unit. However, the present invention is not limited to this, and any structure that does not have flexibility and displays on a flat surface may be used. It may also be composed.

[0485] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. can be done.

[0486] (Embodiment 8) In this embodiment, a light-emitting device including a light-emitting element of one embodiment of the present invention will be described with reference to FIGS. This will be explained using Figure 31.

[0487] FIG. 30(A) is a perspective view of a light emitting device 3000 according to this embodiment. The cross section corresponding to the dashed line EF is shown in FIG. 30(B). In A), some of the components are shown with dashed lines to avoid cluttering the drawing.

[0488] The light emitting device 3000 shown in FIGS. 30(A) and 30(B) includes a substrate 3001 and a light emitting layer on the substrate 3001. an optical element 3005, a first sealing region 3007 provided on the periphery of the light emitting element 3005, and a second sealing region 3007. and a second sealing region 3009 provided on the outer periphery of the first sealing region 3007.

[0489] The light emitted from the light emitting element 3005 is incident on either the substrate 3001 or the substrate 3003. In Figures 30(A) and 30(B), light is emitted from the light emitting element 3005. A configuration in which light is emitted downward (toward the substrate 3001) will be described.

[0490] As shown in FIGS. 30(A) and 30(B), the light emitting device 3000 includes a light emitting element 3005. A double sealing structure is arranged surrounded by a first sealing region 3007 and a second sealing region 3009. The double sealing structure prevents external impurities (e.g. However, the first sealing region 300 7 and the second sealing region 3009 are not necessarily provided. It may be configured with only 007.

[0491] In FIG. 30(B), the first sealing region 3007 and the second sealing region 3009 are , and are provided in contact with the substrate 3001 and the substrate 3003. However, the present invention is not limited to this. For example, one or both of the first sealing region 3007 and the second sealing region 3009 may be formed on the substrate 30. The insulating film or conductive film formed above the insulating film 01 may be provided in contact with the insulating film or conductive film. Alternatively, one or both of the first sealing region 3007 and the second sealing region 3009 may be formed on the substrate. It may be configured to be in contact with the insulating film or conductive film formed below 3003. stomach.

[0492] The substrate 3001 and the substrate 3003 are the same as the substrate 200 described in the previous embodiment. The light emitting element 3005 may have the same structure as the substrate 220. The light-emitting element may have the same configuration as that described above.

[0493] The first sealing region 3007 is made of a material containing glass (for example, glass frit, glass The second sealing region 3009 may be made of a material containing resin. By using a material containing glass for the first sealing region 3007, In addition, the second sealing region 3009 can be made of a material containing a resin. By using this material, it is possible to improve the impact resistance and heat resistance. The first sealing region 3007 and the second sealing region 3009 are not limited to this. The first sealing region 3009 is formed of a material containing resin, and the second sealing region 3009 is formed of a material containing glass. Good too.

[0494] The glass frit may be, for example, magnesium oxide, calcium oxide, Strontium oxide, barium oxide, cesium oxide, sodium oxide, potassium oxide, acid Boron oxide, vanadium oxide, zinc oxide, tellurium oxide, aluminum oxide, silicon dioxide, acid Lead oxide, tin oxide, phosphorus oxide, ruthenium oxide, rhodium oxide, iron oxide, copper oxide, manganese dioxide ZnO, molybdenum oxide, niobium oxide, titanium oxide, tungsten oxide, bismuth oxide, Zirconium oxide, lithium oxide, antimony oxide, lead borate glass, tin phosphate glass , vanadate glass, or borosilicate glass. It is preferable that both contain one or more transition metals.

[0495] The glass frit may be formed by applying a frit paste to a substrate, for example. This is then subjected to heat treatment or laser irradiation. The resin is diluted with an organic solvent (also called a binder). It is also possible to use a material to which an absorbent that absorbs light of the wavelength of the laser light is added. It is preferable to use, for example, an Nd:YAG laser or a semiconductor laser as the laser. Furthermore, the shape of the laser beam may be circular or rectangular.

[0496] Examples of materials containing the above-mentioned resins include polyester, polyolefin, and poly. Amide (nylon, aramid, etc.), polyimide, polycarbonate or acrylic, urea Also, materials containing resins with siloxane bonds can be used. You can be there.

[0497] In addition, either one or both of the first sealing region 3007 and the second sealing region 3009 When a material containing glass is used for the substrate 3001, the thermal expansion coefficient of the material containing glass and the substrate 3001 is By adopting the above-mentioned configuration, the material or substrate containing glass is prevented from being damaged by thermal stress. This can prevent cracks from occurring in the plate 3001.

[0498] For example, the first sealing region 3007 may be made of a material containing glass, and the second sealing region 3009 may be made of a material containing glass. When a material containing resin is used, the following excellent effects are obtained.

[0499] The second sealing region 3009 is closer to the periphery of the light emitting device 3000 than the first sealing region 3007. The light emitting device 3000 is provided on the side closer to the outer periphery. Therefore, the distortion becomes large on the outer peripheral side of the light emitting device 3000, that is, on the second The first sealing region 3009 is sealed with a material containing resin, and the second sealing region 3009 is sealed with a material containing resin. By sealing the first sealing region 3007 provided on the inside with a material containing glass, The light emitting device 3000 is less likely to break even if distortion due to external force or the like occurs.

[0500] As shown in FIG. 30(B), the substrate 3001, the substrate 3003, the first sealing region 30 A first region 3011 is formed in the region surrounded by the second sealing region 3007 and the second sealing region 3009. In addition, the substrate 3001, the substrate 3003, the light emitting element 3005, and the first sealing region 300 In the area surrounded by 7, a second area 3013 is formed.

[0501] The first region 3011 and the second region 3013 may be filled with, for example, a rare gas or a nitrogen gas. It is preferable that the container is filled with an inert gas such as acrylic or epoxy resin. It is preferable that the first region 3011 and the second region 3013 are filled with Preferably, the pressure is reduced below atmospheric pressure.

[0502] Also, a modified example of the configuration shown in Fig. 30(B) is shown in Fig. 30(C). FIG. 3 is a cross-sectional view showing a modified example of the device 3000.

[0503] In FIG. 30(C), a recess is provided in a part of the substrate 3003, and a desiccant 3018 is provided in the recess. The rest of the configuration is the same as that shown in Figure 30(B).

[0504] Desiccants 3018 are substances that adsorb moisture by chemical adsorption or by physical adsorption. Therefore, a substance that absorbs moisture can be used. For example, a desiccant 3018 can be used. The substances that can be used include oxides of alkali metals and oxides of alkaline earth metals (oxides calcium and barium oxide), sulfates, metal halides, perchlorates, zeolites, Examples include silica gel.

[0505] Next, a modified example of the light emitting device 3000 shown in FIG. 30(B) will be described with reference to FIGS. 31(A), (B), (C), and (D) are the same as those in FIG. 30(B). 10 is a cross-sectional view illustrating a modified example of the light emitting device 3000 shown in FIG.

[0506] The light emitting devices shown in FIGS. 31(A), (B), (C), and (D) do not have the second sealing region 3009. 31(A), (B), (C), and (D) are configured as a first sealing region 3007. The light emitting device shown in FIG. 30B has a region 3014 instead of the second region 3013 shown in FIG. do.

[0507] The region 3014 may be made of, for example, polyester, polyolefin, polyamide (nylon), Polyimide, polycarbonate or acrylic, urethane, epoxy Also, a material containing a resin having a siloxane bond can be used. do.

[0508] By using the above-mentioned material for the region 3014, a so-called solid-sealed light-emitting device can be obtained. It is possible.

[0509] 31(B) is the same as the light emitting device shown in FIG. 31(A) on the substrate 3001 side. A substrate 3015 is provided on the substrate 3015 .

[0510] The substrate 3015 has an uneven surface as shown in FIG. is provided on the side where light from the light emitting element 3005 is extracted, The light extraction efficiency can be improved. Instead of the structure having the light emitting element, a substrate that functions as a diffusion plate may be provided.

[0511] 31(C) is the same as the light emitting device shown in FIG. 31(A) except that the light emitting device shown in FIG. While the conventional structure extracts light from the substrate 3003 side, the present structure extracts light from the substrate 3003 side.

[0512] The light-emitting device shown in FIG. 31(C) has a substrate 3015 on the substrate 3003 side. The structure is similar to that of the light-emitting device shown in FIG.

[0513] The light emitting device shown in FIG. 31(D) is the same as the light emitting device shown in FIG. 31(C), The configuration is such that the substrate 3016 is provided instead of the substrate 3015 .

[0514] The substrate 3016 has a first uneven portion located on the side closer to the light emitting element 3005 and a second uneven portion located on the side closer to the light emitting element 300 31(D) and a second uneven portion located on the far side of the first uneven portion. The efficiency of extracting light from the light emitting element 3005 can be further improved.

[0515] Therefore, by implementing the structure shown in this embodiment, impurities such as moisture and oxygen can be prevented. It is possible to realize a light emitting device in which deterioration of the light emitting element due to the above-mentioned phenomenon is suppressed. By implementing the configuration shown in the embodiment, a light emitting device with high light extraction efficiency can be realized. Cut.

[0516] Note that the structure described in this embodiment mode may be combined with structures described in other embodiments as appropriate. can be done.

[0517] (Embodiment 9) In this embodiment, a light-emitting element of one embodiment of the present invention is applied to various lighting devices and electronic devices. An example of this will be described with reference to FIGS. 32 and 33.

[0518] By fabricating the light-emitting element of one embodiment of the present invention over a flexible substrate, it is possible to fabricate a light-emitting element having a curved surface. It is possible to realize electronic devices and lighting devices having light-emitting regions.

[0519] Furthermore, a light-emitting device to which one embodiment of the present invention is applied can also be used for automobile lighting. For example, lighting can be installed on the dashboard, windshield, ceiling, etc.

[0520] FIG. 32(A) shows a perspective view of one side of the multifunction terminal 3500, and FIG. 32(B) shows a perspective view of the multifunction terminal 3500. 3 shows a perspective view of the other side of the multifunction terminal 3500. The multifunction terminal 3500 has a housing 350 2 incorporates a display unit 3504, a camera 3506, a light 3508, etc. The light emitting device of the embodiment can be used for lighting 3508.

[0521] The light emitting device of one embodiment of the present invention is used for the light source 3508, which functions as a surface light source. Therefore, unlike point light sources such as LEDs, light emission with little directionality can be obtained. For example, when the lighting 3508 and the camera 3506 are used in combination, the lighting 3508 is turned on or off. The light 3508 can be illuminated or blinked, and captured by the camera 3506. It functions as a surface light source, allowing you to take photos that look like they were taken under natural light. Cut.

[0522] The multifunction terminal 3500 shown in FIGS. 32(A) and 32(B) is the same as that shown in FIGS. 27(A) to 27(B). As with the electronic device shown in G), it can have a variety of functions.

[0523] In addition, inside the housing 3502, a speaker, a sensor (force, displacement, position, velocity, acceleration, angle Speed, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, Includes functions to measure voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays ), a microphone, etc. By providing a detection device having a sensor for detecting tilt such as an acceleration sensor, it is possible to provide a multi-function The orientation of the terminal 3500 (portrait or landscape) is determined and the screen display of the display unit 3504 is automatically switched. You can make it so that it can be changed.

[0524] The display unit 3504 can also function as an image sensor. By touching the palm or fingers to the sensor 504 and capturing an image of the palm print, fingerprint, etc., personal authentication can be performed. In addition, the display unit 3504 may be provided with a backlight that emits near-infrared light or a sensor that emits near-infrared light. If a light source for imaging is used, it is also possible to image finger veins, palm veins, etc. The light-emitting device of one embodiment of the present invention may be applied to 04.

[0525] FIG. 32(C) shows a perspective view of a security light 3600. The light 3600 is The housing 3602 has a light 3608 on the outside, and the housing 3602 is equipped with a speaker 3610 and the like. The light-emitting device of one embodiment of the present invention can be used for lighting 3608.

[0526] Light 3600 may include, for example, a device for grasping, holding, or holding light 3608. The inside of the housing 3602 is provided with a light 3600. The light emitting device may be provided with an electronic circuit that can control the light emitting method. Alternatively, a circuit that can emit light intermittently multiple times may be used, or the current value of the light emission may be controlled. The circuit may be configured so that the amount of light emitted can be adjusted by adjusting the amount of light emitted. At the same time, a circuit may be incorporated to output a loud alarm sound from the speaker 3610. stomach.

[0527] The Light 3600 can emit light in any direction, so it can be used to target, for example, thugs. It can be used to scare off predators with light or light and sound. It may also be equipped with a camera such as a still camera, or a function having a photography function.

[0528] FIG. 33 shows an example in which the light-emitting element is used as an indoor lighting device 8501. Since the surface area can be increased, a large-area lighting device can be formed. By using a housing having the above structure, a lighting device 8502 having a curved light-emitting area can be formed. The light-emitting element shown in this embodiment mode has a thin film shape, and the housing can be designed with a high degree of freedom. Therefore, it is possible to create lighting devices with various elaborate designs. A large lighting device 8503 may be provided on the wall. A touch sensor may be provided in 503 to turn the power on or off.

[0529] In addition, by using light-emitting elements on the surface of the table, it has the function of a table. The lighting device 8504 can be used as a lighting device. This allows the lighting device to function as furniture.

[0530] In this manner, a lighting device and an electronic device can be obtained by applying the light-emitting device of one embodiment of the present invention. The applicable lighting devices and electronic devices include the lighting devices exemplified in this embodiment. It can be applied to lighting devices and electronic devices in all fields, not just lighting devices and electronic devices. is.

[0531] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. You can be there. [Example]

[0532] Example 1 In this example, a manufacturing example of light-emitting elements (light-emitting element 1 and light-emitting element 2) according to one embodiment of the present invention is described. A cross-sectional view of the light-emitting device fabricated in this example is shown in FIG. 34, and the details of the device structure are shown in Table 1. The structures and abbreviations of the compounds used are shown below.

[0533] [ka]

[0534] [Table 1]

[0535] <Fabrication of light-emitting devices> <Fabrication of Light-Emitting Device 1> An ITSO film was formed as an electrode 101 on a substrate 200 to a thickness of 70 nm. The electrode area of ​​the electrode 101 is 4 mm 2 (2mm x 2mm).

[0536] Next, 4,4',4''-(benzene-1, 3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II) and oxidized moiety DBT3P-II:MoO3 is 1:0.5 by weight. The co-evaporation was carried out so that the thickness of the layer was 60 nm.

[0537] Next, on the hole injection layer 111, 4-phenyl-4'-(9-phenyl-4'-phenyl)- (phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP) The deposition was carried out so that the thickness was nm.

[0538] Next, a layer 160(1) of the light-emitting layer 160 was formed on the hole transport layer 112 using 2-[3′-(diphenyl ether) Benzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II) and N-(1,1'-biphenyl-4-yl)- N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl bis(2,3,5-trimethyl-9H-fluoren-2-amine) (triphenylpyrazinate)(dipivaloylmethanato)iridium(III) (abbreviation: Ir( tppr)2(dpm)) and a weight ratio of (2mDBTBPDBq-II:PCBBiF: Ir(tppr)2(dpm)) is 0.7:0.3:0.05, and the thickness is Then, as the layer 160(2), a layer of 2mDBTB was co-evaporated to a thickness of 20 nm. PDBq-II:PCBBiF:Ir(tppr)2(dpm)) 0.8:0.2:0 The light-emitting layer 160 was co-deposited to a thickness of 20 nm. In this study, 2mDBTBPDBq-II was the first organic compound and PCBBiF was the second. and Ir(tppr)2(dpm) is the guest material (phosphorescent material).

[0539] Next, on the light-emitting layer 160, a layer 118(1) of the electron transport layer 118 containing 2mDBTBP DBq-II was then deposited as layer 118(2) to a thickness of 20 nm. Anthroline (abbreviation: BPhen) was then deposited to a thickness of 15 nm. Then, lithium fluoride (LiF) was deposited to a thickness of 1000 nm on the electron transport layer 118 as the electron injection layer 119. The deposition was carried out so that the thickness was 1 nm.

[0540] Next, on the electron injection layer 119, aluminum (Al) was deposited to a thickness of 20 It was formed so that the thickness was 0 nm.

[0541] Next, the device is sealed using a sealant for organic EL in a glove box with a nitrogen atmosphere. The substrate 220 for forming the light emitting element 1 is fixed to the substrate 200 on which the organic material is formed. Specifically, a sealant was applied to the periphery of the substrate 220, and the substrate 220 and the organic material were sealed. and a substrate 200 on which the 2 Irradiation The resulting mixture was then heat-treated at 80° C. for 1 hour. Light-emitting element 1 was obtained through the above steps.

[0542] <Fabrication of light-emitting element 2> The light-emitting element 2 differs from the light-emitting element 1 described above in the fabrication process only in the material of the electron transport layer 118. The other steps were the same as those for the light-emitting element 1.

[0543] That is, the layer 118(1) of the electron transport layer 118 of the light-emitting element 2 contains 2mDBTBPD Bq-II was then deposited to a thickness of 20 nm, followed by 2,9-bis(2,4-dichloro-2,6-dichloro-1,6 ... bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviated :NBPhen) were successively evaporated to a thickness of 15 nm.

[0544] <Emission spectrum of host material> Here, the host material (the first organic compound and the second organic compound) of the light-emitting device fabricated above The development of thin films of 2mDBTBPDBq-II alone and PCBBiF alone was performed as a The optical spectrum was measured and the mixture of 2mDBTBPDBq-II and PCBBiF was The emission spectrum of the film was measured and the results are shown in FIG.

[0545] To measure the above emission spectrum, a thin film sample was prepared on a quartz substrate by vacuum deposition. The emission spectrum was measured using a PL-EL measurement device (Hamamatsu Photonics). The measurement was carried out at room temperature (an atmosphere maintained at 23°C). In addition, the mixing ratio of the two compounds in the mixed thin film (first organic compound: second organic compound) was The ratio of the organic compound was 0.8:0.2.

[0546] As shown in Figure 35, the luminescence of the mixed thin film of 2mDBTBPDBq-II and PCBBiF The spectra are the emission spectra of 2mDBTBPDBq-II alone and PCBBiF alone. As will be shown later, the results show that the 2mDBTB The LUMO level of PDBq-II is lower than that of PCBBiF. The HOMO level of 2mDBTBPDBq-II is higher than that of 2mDBTBPDBq-II. The luminescence of the mixed thin film of BTBPDBq-II and PCBBiF was The energy difference between the LUMO level of I and the HOMO level of PCBBiF is roughly equivalent to The light emitted by the mixed thin film is similar to that of 2mDBTBPDBq-II alone and PCB The emission from the mixed thin film has a longer wavelength (lower energy) than that of BiF alone. This can be said to be the emission from the exciplex formed by the compound. -II and PCBBiF are organic compounds that form an exciplex with each other, By using 2mDBTBPDBq-II and PCBBiF as host materials, ExT Light-emitting devices can be fabricated that utilize ET.

[0547] <Absorption and emission spectra of guest materials> Next, we investigated the absorption spectra of Ir(tppr)2(dpm), the guest material used in the light-emitting device. The measurement results of the spectrum and emission spectrum are shown in FIG.

[0548] To measure the absorption spectrum, the guest material (Ir(tppr)2(dpm)) was dissolved in water. A dichloromethane solution containing the compound was prepared, and the absorption spectrum was measured using a quartz cell. The spectra were measured using an ultraviolet-visible spectrophotometer (V550, manufactured by JASCO Corporation). The absorption spectrum of the quartz cell was subtracted from the measured absorption spectrum. The spectra were measured using a PL-EL measuring device (Hamamatsu Photonics). The above measurements were carried out at room temperature (an atmosphere maintained at 23°C).

[0549] As shown in Figure 36, the lowest peak in the absorption spectrum of Ir(tppr)2(dpm) The absorption band on the energy side (long wavelength side) is around 580 nm. From the data, the absorption edge was calculated and the transition energy was estimated assuming a direct transition. The absorption edge of (tppr)2(dpm) is at 596 nm, and the transition energy is 2.08 eV. It was calculated that:

[0550] Therefore, the lowest energy in the absorption spectrum of Ir(tppr)2(dpm) The absorption band on the -side (long wavelength side) is formed by 2mDBTBPDBq-II and PCBBiF. It has an overlapping region with the emission spectrum exhibited by the exciplex (emission spectrum shown in Figure 35). Therefore, the emission of 2mDBTBPDBq-II and PCBBiF as host materials Device 1 and Light-Emitting Device 2 can effectively transfer excitation energy to guest materials .

[0551] As described above, the light-emitting element 1 and the light-emitting element 2 contain the first organic compound 2mDBTBP. The combination of DBq-II and the second organic compound, PCBBiF, forms an exciplex. The light-emitting device has a combination of the above host materials.

[0552] <Phosphorescence spectrum of host material> Next, the first organic compound (2mDBTBPDBq-II) used as the host material and The measurement results of the triplet excitation energy level of the second organic compound (PCBBiF) are shown in Figure 37. vinegar.

[0553] The triplet excitation energy level was measured by phosphorescence measurement of thin film samples of each compound. The measurements were carried out using a micro PL microscope, LabRAM HR-PL (Mitsubishi Electric Industries, Ltd.). The measurement temperature was 10K and the excitation light was a He-Cd laser (325 nm). The most significant difference in the phosphorescence spectrum obtained from the measurement was The triplet excitation energy level was also determined from the peak on the short wavelength side.

[0554] In FIG. 37, the first organic compound (2mDBTBPDBq-II) and the second organic compound (2mDBTBPDBq-II) are The wavelengths of the shortest wavelength peaks in the phosphorescence spectrum of the compound (PCBBiF) are 515 nm and 509 nm, the triplet excited energy levels are 2 The values ​​were derived as 0.41 eV and 2.44 eV.

[0555] In addition, the shortest phosphorescence spectra of 2mDBTBPDBq-II and PCBBiF The peak wavelengths on the wavelength side are 2mDBTBPDBq-II and PCBBiF shown in Figure 35. The wavelengths shorter than the peak wavelength on the shortest wavelength side of the emission spectrum of the exciplex formed are In addition, an exciplex is an electron complex that exists between a singlet excited energy level and a triplet excited energy level. Since the triplet excited energy level of the exciplex is characterized by a small energy difference, It can be derived from the peak wavelength on the shortest wavelength side of the emission spectrum. of the first organic compound (2mDBTBPDBq-II) and the second organic compound (PCBBiF) The triplet excited energy level can be said to be higher than the triplet excited energy level of the exciplex.

[0556] In addition, the guest material (Ir(tp From the transition energy (2.08 eV) of pr)2(dpm)), 2mDBTBPDBq- The triplet excited energy levels of II and PCBBiF are high.

[0557] Therefore, the first organic compound (2mDBTBPD) used as the host material in this example Bq-II) and a second organic ...

Claims

1. a light-emitting layer including a metal complex having a platinum group element, a first organic compound, and a second organic compound; a LUMO level of the first organic compound is lower than a LUMO level of the second organic compound; the HOMO level of the first organic compound is lower than the HOMO level of the second organic compound; a LUMO level of the metal complex having a platinum group element is lower than a LUMO level of the first organic compound; an energy difference between a LUMO level and a HOMO level of the metal complex having a platinum group element is larger than an energy difference between a LUMO level of the first organic compound and a HOMO level of the second organic compound; the first organic compound and the second organic compound are a combination that forms an exciplex, the first organic compound is a heterocyclic compound having any one of a triazine skeleton, a pyrimidine skeleton, a pyridazine skeleton, and a pyridine skeleton, the second organic compound is a compound having any one of a pyrrole skeleton, a furan skeleton, a thiophene skeleton, and an aromatic amine skeleton; Light emitting element.

2. a light-emitting layer including a metal complex having a platinum group element, a first organic compound, and a second organic compound; a LUMO level of the first organic compound is lower than a LUMO level of the second organic compound; the HOMO level of the first organic compound is lower than the HOMO level of the second organic compound; a LUMO level of the metal complex having a platinum group element is lower than a LUMO level of the first organic compound; an energy difference between a LUMO level and a HOMO level of the metal complex having a platinum group element is larger than an energy difference between a LUMO level of the first organic compound and a HOMO level of the second organic compound; the first organic compound and the second organic compound are a combination that forms an exciplex, the first organic compound is any one of an oxadiazole derivative, a triazole derivative, a benzimidazole derivative, a phenanthroline derivative, a pyridine derivative, a bipyridine derivative, a pyrimidine derivative, and a triazine derivative; the second organic compound is a compound having any one of a pyrrole skeleton, a furan skeleton, a thiophene skeleton, and an aromatic amine skeleton; Light emitting element.

3. a light-emitting layer including a metal complex having a platinum group element, a first organic compound, and a second organic compound; a LUMO level of the first organic compound is lower than a LUMO level of the second organic compound; the HOMO level of the first organic compound is lower than the HOMO level of the second organic compound; a LUMO level of the metal complex having a platinum group element is lower than a LUMO level of the first organic compound; an energy difference between a LUMO level and a HOMO level of the metal complex having a platinum group element is larger than an energy difference between a LUMO level of the first organic compound and a HOMO level of the second organic compound; the first organic compound and the second organic compound are a combination that forms an exciplex, an energy difference between a LUMO level of the metal complex having a platinum group element and a HOMO level of the second organic compound is equal to or greater than a transition energy calculated from an absorption edge in an absorption spectrum of the metal complex having a platinum group element; the first organic compound is a heterocyclic compound having any one of a triazine skeleton, a pyrimidine skeleton, a pyridazine skeleton, and a pyridine skeleton, the second organic compound is a compound having any one of a pyrrole skeleton, a furan skeleton, a thiophene skeleton, and an aromatic amine skeleton; Light emitting element.

4. a light-emitting layer including a metal complex having a platinum group element, a first organic compound, and a second organic compound; a LUMO level of the first organic compound is lower than a LUMO level of the second organic compound; the HOMO level of the first organic compound is lower than the HOMO level of the second organic compound; a LUMO level of the metal complex having a platinum group element is lower than a LUMO level of the first organic compound; an energy difference between a LUMO level and a HOMO level of the metal complex having a platinum group element is larger than an energy difference between a LUMO level of the first organic compound and a HOMO level of the second organic compound; the first organic compound and the second organic compound are a combination that forms an exciplex, an energy difference between a LUMO level of the metal complex having a platinum group element and a HOMO level of the second organic compound is equal to or greater than a transition energy calculated from an absorption edge in an absorption spectrum of the metal complex having a platinum group element; the first organic compound is any one of an oxadiazole derivative, a triazole derivative, a benzimidazole derivative, a phenanthroline derivative, a pyridine derivative, a bipyridine derivative, a pyrimidine derivative, and a triazine derivative; the second organic compound is a compound having any one of a pyrrole skeleton, a furan skeleton, a thiophene skeleton, and an aromatic amine skeleton; Light emitting element.

5. a light-emitting layer including a metal complex having a platinum group element, a first organic compound, and a second organic compound; a LUMO level of the first organic compound is lower than a LUMO level of the second organic compound; the HOMO level of the first organic compound is lower than the HOMO level of the second organic compound; a LUMO level of the metal complex having a platinum group element is lower than a LUMO level of the first organic compound; an energy difference between a LUMO level and a HOMO level of the metal complex having a platinum group element is larger than an energy difference between a LUMO level of the first organic compound and a HOMO level of the second organic compound; the first organic compound and the second organic compound are a combination that forms an exciplex, an energy difference between a LUMO level of the metal complex having a platinum group element and a HOMO level of the second organic compound is equal to or greater than an emission energy exhibited by the metal complex having a platinum group element; the first organic compound is a heterocyclic compound having any one of a triazine skeleton, a pyrimidine skeleton, a pyridazine skeleton, and a pyridine skeleton, the second organic compound is a compound having any one of a pyrrole skeleton, a furan skeleton, a thiophene skeleton, and an aromatic amine skeleton; Light emitting element.

6. a light-emitting layer including a metal complex having a platinum group element, a first organic compound, and a second organic compound; a LUMO level of the first organic compound is lower than a LUMO level of the second organic compound; the HOMO level of the first organic compound is lower than the HOMO level of the second organic compound; a LUMO level of the metal complex having a platinum group element is lower than a LUMO level of the first organic compound; an energy difference between a LUMO level and a HOMO level of the metal complex having a platinum group element is greater than an energy difference between a LUMO level of the first organic compound and a HOMO level of the second organic compound; the first organic compound and the second organic compound are a combination that forms an exciplex, an energy difference between a LUMO level of the metal complex having a platinum group element and a HOMO level of the second organic compound is equal to or greater than an emission energy exhibited by the metal complex having a platinum group element; the first organic compound is any one of an oxadiazole derivative, a triazole derivative, a benzimidazole derivative, a phenanthroline derivative, a pyridine derivative, a bipyridine derivative, a pyrimidine derivative, and a triazine derivative; the second organic compound is a compound having any one of a pyrrole skeleton, a furan skeleton, a thiophene skeleton, and an aromatic amine skeleton; Light emitting element.

7. In any one of claims 1 to 6, an energy difference between a LUMO level and a HOMO level of the metal complex having a platinum group element is 0.4 eV or more larger than a transition energy calculated from an absorption edge in an absorption spectrum of the metal complex having a platinum group element; Light emitting element.

8. In any one of claims 1 to 7, an energy difference between a LUMO level and a HOMO level of the metal complex having a platinum group element is 0.4 eV or more larger than an emission energy exhibited by the metal complex having a platinum group element; Light emitting element.

9. In any one of claims 1 to 8, an emission spectrum exhibited by the exciplex has a region overlapping with an absorption band on the longest wavelength side of an absorption spectrum of the metal complex having a platinum group element; Light emitting element.

10. In any one of claims 1 to 9, The metal complex having a platinum group element has ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), or platinum (Pt). Light emitting element.

11. A light-emitting element according to any one of claims 1 to 10, A color filter, a seal, or a transistor; A display device having the above configuration.

12. A display device according to claim 11; A housing or a touch sensor; An electronic device having the

13. A light-emitting element according to any one of claims 1 to 10, A housing or a touch sensor; A lighting device having the above structure.

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