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

Abstract

To provide a light-emitting element emitting light with a broad light emission spectrum.SOLUTION: The combination of a first organic compound and a second organic compound forms an exciplex. The first organic compound has a function of converting triplet excited energy into light emission. The lowest triplet excited level of the second organic compound is more than or equal to the lowest triplet excited level of the first organic compound. The lowest triplet excited level of the first organic compound is more than or equal to the lowest triplet excited level of the exciplex. The light emission from a light-emitting layer in a light-emitting element includes the light emission from the first organic compound and the light emission from the 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 the present 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, etc. 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 substance (EL layer) is sandwiched between a pair of electrodes. By applying a voltage between them, light is emitted from the luminescent material.

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

[0005] An EL device that uses an organic compound as a light-emitting substance and has the light-emitting organic compound between a pair of electrodes In the case of a light-emitting element having a layer (for example, an organic EL element), a voltage is applied between a pair of electrodes. As a result, electrons are injected from the cathode and holes are injected from the anode into the light-emitting EL layer. The injected electrons and holes are then recombined to produce light-emitting The organic compound is excited, and light can be emitted from the excited luminescent organic compound. do.

[0006] The types of excited states that organic compounds can form include singlet excited states (S * ) and triplet excitation Status(T * ) in which the emission from the singlet excited state is fluorescent and the emission from the triplet excited state is phosphorescent. The statistical generation ratio of these in a light-emitting element is S * :T * = Therefore, compared to a light-emitting element using a compound that emits fluorescence (a fluorescent compound), Light-emitting elements that use compounds that emit phosphorescence (phosphorescent compounds) have higher luminous efficiency. Therefore, it is possible to convert the energy of the triplet excited state into light emission. 2. Description of the Related Art In recent years, light-emitting devices using phosphorescent compounds have been actively developed.

[0007] Phosphorescent materials are known as materials that can convert part of the energy of the triplet excited state into light emission. In addition to the compounds, we also developed thermally activated delayed fluorescence (TDF) Thermally activated delayed fluorescence (TADF) materials are known. In materials, a singlet excited state is generated from a triplet excited state by reverse intersystem crossing, and the singlet excited The light is converted from a state to light.

[0008] The exciplex formed by two types of organic compounds has energies of singlet and triplet excited states. Since the energy difference is small, a method of using the exciplex as a thermally activated delayed fluorescence material is proposed. (See, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2014-45184 A Summary of the Invention [Problem to be solved by the invention]

[0010] In order to increase the luminous efficiency of a light-emitting device having a thermally activated delayed fluorescent material, triplet It is preferable that the singlet excited state is efficiently generated from the excited state. For light-emitting devices that use exciplexes as materials, we are developing methods to further improve the luminous efficiency. What is required is...

[0011] In order to obtain multicolor light such as white light from a light-emitting element, it is necessary to use light-emitting substances that exhibit different colors. At the same time, it is necessary to emit light efficiently, but it is difficult to control the emission color to obtain the desired color. .

[0012] Therefore, one object of one embodiment of the present invention is to provide a light-emitting element with high emission efficiency. Alternatively, in one embodiment of the present invention, a light-emitting element that emits light with a wide emission spectrum is provided. Another object of the present invention is to provide a semiconductor device having reduced power consumption. Another object of the present invention is to provide a light-emitting element. Another object of the present invention is to provide a novel light-emitting device. Another object of the present invention is to provide a novel display device. One of the challenges we face is to

[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 aspect of the present invention is a light-emitting device having two organic compounds that form an exciplex. It is a device in which one organic compound has a function of converting triplet excitation energy into light emission. It is a light emitting element having a light emitting function.

[0015] Another embodiment of the present invention is a light-emitting element having a light-emitting layer, the light-emitting layer comprising a first organic compound. and a second organic compound, is a LUMO level of the first organic compound and the second organic compound that is equal to or higher than the other LUMO level of the first organic compound and the second organic compound. and the HOMO level of the first organic compound and the HOMO level of the second organic compound are higher than or equal to the HOMO level of the other of the first organic compound and the second organic compound. A compound having an OMO level and in which a first organic compound and a second organic compound form an exciplex. The first organic compound is capable of converting triplet excitation energy into luminescence. The lowest excited triplet level of the second organic compound is lower than the lowest excited triplet level of the first organic compound. The lowest excited triplet level of the first organic compound is equal to or higher than the lowest excited triplet level of the exciplex. The light emitted from the light-emitting layer is light emitted from the first organic compound, and the light emitted from the light-emitting layer is light emitted from the first organic compound. The light-emitting element emits light emitted by an exciplex.

[0016] Another embodiment of the present invention is a light-emitting element having a light-emitting layer. The light-emitting layer includes a first conductive layer. and a second organic compound, the LUMO level of the first organic compound being lower than that of the second organic compound. The HOMO level of the first organic compound is equal to or higher than the LUMO level of the second organic compound. The first organic compound and the second organic compound form an exciplex at a HOMO level or higher. The first organic compound has an absorption band of a triplet MLCT transition. The lowest excited triplet level of the second organic compound is a metal complex having a structure similar to that of the first organic compound. The lowest excited triplet level of the first organic compound is equal to or higher than the lowest excited triplet level of the exciplex The light emitted from the light-emitting layer is equal to or higher than the lowest excited triplet level of the first organic compound. The light emitting element is a light emitting element that emits light and emits light emitted by an exciplex.

[0017] In each of the above configurations, the intensity of the luminescence exhibited by the exciplex and the luminescence exhibited by the first organic compound The ratio is preferably 1:9 to 9:1. The emission of the exciplex is also It is preferable that the luminescence intensity is higher than that exhibited by the compound.

[0018] In addition, the light-emitting element having each of the above structures further includes a third organic compound. The HOMO level of the third organic compound is preferably equal to or higher than the HOMO level of the second organic compound. The organic compound preferably has a function of transporting holes. The compound has at least one of a π-electron rich heteroaromatic skeleton and an aromatic amine skeleton. It is preferable to do so.

[0019] In each of the above structures, the second organic compound has a function of transporting electrons. It is preferable that the second organic compound has a π-electron deficient heteroaromatic skeleton. preferable.

[0020] In each of the above structures, the first organic compound preferably contains iridium. The first organic compound has a ligand that coordinates with iridium, and the ligand is a nitrogen-containing five-membered complex. It is preferable that the compound has a monocyclic skeleton.

[0021] Another embodiment of the present invention is a light-emitting element having any of the above structures, and a color filter or a transistor. and at least one of a first transistor and a second transistor. The electronic device has the display device and at least one of a housing and a touch sensor. Another embodiment of the present invention is a display device including a light-emitting element having any of the above structures and at least one housing or a touch sensor. Another embodiment of the present invention is a lighting device having a light-emitting element. The term "light emitting device" includes not only optical devices but also electronic devices having light emitting devices. The light-emitting device in this specification refers to an image display device or a light source (including a lighting device). Connectors for optical elements, such as FPC (Flexible Printed Circuit) t), TCP (Tape Carrier Package) mounted display module A display module with a printed wiring board at the end of the TCP, or a light-emitting element with C Display with IC (integrated circuit) directly mounted using OG (Chip On Glass) method The module may also be included in the light emitting device. Effect of the Invention

[0022] According to one embodiment of the present invention, a light-emitting element with high emission efficiency can be provided. According to one embodiment of the present invention, it is possible to provide a light-emitting element that emits light with a wide emission spectrum. According to another 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 novel light-emitting element can be provided. According to one embodiment of the present invention, a novel light-emitting device can be provided. According to one embodiment of the present invention, a novel display device can be provided.

[0023] Note that 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 are described in the specification. The disclosure of the specification, drawings, claims, etc. is self-evident, and the disclosure of the specification, drawings, claims, etc. is self-evident. From this, it is possible to extract other effects. [Brief description of the drawings]

[0024] [Figure 1] 1 is a schematic cross-sectional view of a light-emitting element according to one embodiment of the present invention. [Diagram 2] 1A and 1B are schematic cross-sectional views of a light-emitting layer of a light-emitting element according to one embodiment of the present invention and a diagram illustrating the correlation between energy levels. [Diagram 3] 1A and 1B are schematic cross-sectional views of a light-emitting layer of a light-emitting element according to one embodiment of the present invention and a diagram illustrating the correlation between energy levels. [Figure 4] 1A and 1B are diagrams illustrating the correlation between energy levels of a light-emitting layer of a light-emitting element according to one embodiment of the present invention. [Diagram 5] 1 is a schematic cross-sectional view of a light-emitting element according to one embodiment of the present invention. [Figure 6] 1 is a schematic cross-sectional view of a light-emitting element according to one embodiment of the present invention. [Figure 7] 1 is a schematic cross-sectional view of a light-emitting element according to one embodiment of the present invention. [Figure 8] 1A and 1B are a top view and a cross-sectional schematic diagram illustrating a display device of one embodiment of the present invention. [Figure 9]1A and 1B are schematic cross-sectional views illustrating a display device according to 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 to 1C illustrate electronic devices of one embodiment of the present invention. [Figure 12] FIG. 1 is a perspective view illustrating a display device according to one embodiment of the present invention. [Figure 13] 1A to 1C are diagrams illustrating a lighting device according to one embodiment of the present invention. [Figure 14] FIG. 13 is a graph showing luminance-current density characteristics of a light-emitting element in the example. [Figure 15] FIG. 13 is a graph showing luminance-voltage characteristics of a light-emitting element in the example. [Figure 16] FIG. 13 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 17] FIG. 13 is a graph showing power efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 18] FIG. 2 is a graph showing electroluminescence spectra of light-emitting elements according to an embodiment of the present invention. [Figure 19] FIG. 2 is a graph showing electroluminescence spectra of light-emitting elements according to an embodiment of the present invention. [Figure 20] FIG. 13 is a graph showing luminance-current density characteristics of a light-emitting element in the example. [Figure 21] FIG. 13 is a graph showing luminance-voltage characteristics of a light-emitting element in the example. [Figure 22] FIG. 13 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 23] FIG. 13 is a graph showing power efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 24] FIG. 2 is a graph showing electroluminescence spectra of light-emitting elements according to an embodiment of the present invention. [Diagram 25] FIG. 2 is a graph showing electroluminescence spectra of light-emitting elements according to an embodiment of the present invention. [Figure 26] FIG. 4 is a diagram illustrating an emission spectrum of a thin film according to an embodiment. [Figure 27] FIG. 4 is a diagram illustrating an emission spectrum of a thin film according to an embodiment. [Figure 28]FIG. 4 is a diagram illustrating the absorption spectrum of a guest material in the example. [Figure 29] FIG. 13 is a graph showing luminance-current density characteristics of a light-emitting element in the example. [Diagram 30] FIG. 13 is a graph showing luminance-voltage characteristics of a light-emitting element in the example. [Diagram 31] FIG. 13 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Diagram 32] FIG. 13 is a graph showing power efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Diagram 33] FIG. 2 is a graph showing electroluminescence spectra of light-emitting elements according to an embodiment of the present invention. [Diagram 34] FIG. 2 is a graph showing electroluminescence spectra of light-emitting elements according to an embodiment of the present invention. [Diagram 35] FIG. 4 is a diagram illustrating an emission spectrum of a thin film according to an embodiment. [Diagram 36] FIG. 4 is a diagram illustrating an emission spectrum of a thin film according to an embodiment. [Figure 37] FIG. 4 is a diagram illustrating the absorption spectrum of a guest material in the example. [Figure 38] FIG. 4 is a diagram illustrating transient light emission characteristics of a thin film in an embodiment. [Figure 39] FIG. 4 is a diagram illustrating a time-resolved emission spectrum of a thin film in an example. [Diagram 40] FIG. 4 is a diagram illustrating an emission spectrum of a thin film according to an embodiment. [Diagram 41] FIG. 4 is a diagram illustrating an emission spectrum of a thin film according to an embodiment. [Diagram 42] FIG. 4 is a diagram illustrating transient light emission characteristics of a thin film in an embodiment. [Diagram 43] FIG. 4 is a diagram illustrating transient light emission characteristics of a thin film in an embodiment. [Diagram 44] FIG. 4 is a diagram illustrating an emission spectrum of a thin film according to an embodiment. [Diagram 45] FIG. 4 is a diagram illustrating the absorption spectrum of a guest material in the example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, the embodiment 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 are not limited to those described above 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 of the present disclosure are not to be construed as being limited to the content.

[0026] In addition, the position, size, range, etc. of each component shown in the drawings are not necessarily shown in order to facilitate understanding. The actual position, size, range, etc. may not be shown. The present invention is not necessarily limited to the position, size, range, etc. disclosed in the drawings, etc.

[0027] In addition, in this specification, ordinal numbers such as 1st, 2nd, etc. are used for convenience. In some cases, the order of steps or layers may not be indicated. For example, "first" may be replaced with "second" or " " can be appropriately replaced with "the third" etc. The ordinal numbers used to identify an aspect of the present invention may not match those used in the present invention. be.

[0028] In addition, in this specification and the like, when explaining the configuration of the invention using drawings, The reference numerals may be commonly used among different drawings.

[0029] 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:

[0030] In the present specification and the like, the singlet excited state (S* ) is a single charge with excitation energy The S1 level is the lowest singlet excited energy level. , the lowest excited energy level of the singlet state (S1 state). term excited state (T * ) is a triplet state with an excited energy. The lowest triplet excited energy level is the lowest triplet excited state (T1 In this specification and the like, the term "singlet excited state" refers to the excited energy level of the singlet excited state. Even when written as states and singlet excited energy levels, the S1 state and S1 level The triplet excited state and triplet excited energy level are also used. Even in this case, it may refer to a T1 state and a T1 level.

[0031] In the present specification and the like, a fluorescent compound refers to a compound that relaxes from a singlet excited state to a ground state. Phosphorescent compounds are compounds that emit light in the visible light region when emitted from a triplet excited state. It is a compound that emits light in the visible light region at room temperature when it relaxes to the bottom state. A phosphorescent compound is one of the compounds that can convert triplet excitation energy into visible light.

[0032] In this specification and the like, room temperature refers to a temperature in the range of 0°C or higher and 40°C or lower.

[0033] In this specification, the blue wavelength range is from 400 nm to less than 490 nm. The blue light emission has at least one emission spectrum peak in the wavelength region. The green wavelength region is 490 nm or more and less than 580 nm, and green emission is within this wavelength region. It has at least one emission spectrum peak. The red wavelength region is 580 nm. and the red emission has at least one emission spectrum in the wavelength range. It has a peak.

[0034] (Embodiment 1) In this embodiment, a light-emitting element of one embodiment of the present invention will be described below with reference to FIGS. Reveal.

[0035] <Configuration example 1 of light-emitting element> First, a structure of a light-emitting element of one embodiment of the present invention will be described below with reference to FIG.

[0036] FIG. 1 is a schematic cross-sectional view of a light-emitting element 150 according to one embodiment of the present invention.

[0037] The light emitting element 150 has a pair of electrodes (electrode 101 and electrode 102). The EL layer 100 includes at least a light-emitting layer 130. .

[0038] In addition to the light-emitting layer 130, the EL layer 100 shown in FIG. It has functional layers such as layer 112 , an electron transport layer 118 , and an electron injection layer 119 .

[0039] In this embodiment, of the pair of electrodes, electrode 101 is an anode, and electrode 1 Although the description will be given assuming that 02 is a cathode, the configuration of the light-emitting element 150 is not limited to this. The electrode 101 is a cathode, the electrode 102 is an 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 that order. The light-emitting layer 130, the electron transport layer 118, and the electron injection layer 119 may be laminated in this order. .

[0040] The configuration of the EL layer 100 is not limited to the configuration shown in FIG. At least one selected from the group consisting of the transport layer 112, the electron transport layer 118, and the electron injection layer 119. Alternatively, the EL layer 100 may have a hole or electron injection barrier. reduce, improve the transportability of holes or electrons, inhibit the transportability of holes or electrons, or or a functional layer having a function of suppressing a quenching phenomenon caused by an electrode. The functional layers may each be a single layer or a laminate of multiple layers. It is also possible.

[0041] <Light Emitting Mechanism of Light Emitting Device 1> Next, the light emitting mechanism of the light emitting layer 130 will be described below.

[0042] FIG. 2(A) is a schematic cross-sectional view showing an example of the light-emitting layer 130 shown in FIG. The light-emitting layer 130 shown includes a guest material 131 and a host material 132 .

[0043] In the light-emitting element 150 according to one embodiment of the present invention, a pair of electrodes (electrode 101 and electrode 102) By applying a voltage between the cathode and the anode, electrons flow from the cathode and holes flow from the anode. The electrons and holes are then injected into the EL layer 100, causing a current to flow. Excitons are formed by the recombination of carriers (electrons and holes). The ratio of singlet excitons to triplet excitons (hereafter referred to as exciton generation probability) is statistically The probability of generating singlet excitons is 1:3. In other words, the rate of generating singlet excitons is 25%. Since the rate at which triplet excitons are generated is 75%, it is possible to make triplet excitons contribute to light emission. However, this is important for improving the luminous efficiency of the light-emitting element.

[0044] Therefore, the light-emitting material used in the light-emitting layer 130 is a material that converts triplet excitation energy into light emission. Among the luminescent compounds, those that emit phosphorescence are preferred. Compounds that can convert triplet excitation energy into light emission (hereafter referred to as phosphorescent compounds) Therefore, a phosphorescent compound is used as the light-emitting material of the light-emitting element 150. This is preferable.

[0045] When a phosphorescent compound is used as the light-emitting material in the light-emitting layer 130, the T1 The level is lower than the T1 level of other materials (such as the host material 132) contained in the light-emitting layer 130. This is preferable because quenching of the triplet excitation energy of the phosphorescent compound is unlikely to occur. This makes it possible to efficiently obtain light emission from the phosphorescent compound.

[0046] In addition, phosphorescent compounds are known as materials that have the function of converting triplet excitation energy into light emission. In addition to these, thermally activated delayed fluorescent (TADF) materials are also available. The difference between the S1 and T1 levels is small, and the triplet excitation energy is increased by reverse intersystem crossing. It is a material that has the function of converting energy from 1H to singlet excitation energy. Triplet excitation energy is upconverted to singlet excitation energy by a small amount of thermal energy. It is possible to undergo reverse intersystem crossing and efficiently emit light (fluorescence) from the singlet excited state. It is possible to form an excited state with two types of substances, called an exciplex. (also called exciplex) emits part of the triplet excitation energy Therefore, it has the function of a thermally activated delayed fluorescent material that can be converted into a light-emitting element. As the luminescent material of the molecule 150, an exciplex is preferably used.

[0047] When an exciplex is used as the light-emitting material in the light-emitting layer 130, the T1 level of the exciplex is It is preferable that the T1 level is lower than the T1 level of other materials (such as the host material 132) contained in the optical layer 130. This makes it difficult for the triplet excitation energy of the exciplex to be quenched, and the exciplex Reverse intersystem crossing of the triplet excitation energy by Light emission can be obtained efficiently.

[0048] According to the above energy level relationship, the phosphorescent compound and the exciplex are By using it as a light-emitting material, it is possible to efficiently obtain light emission based on both the phosphorescent compound and the exciplex. However, if a phosphorescent compound is used as the guest material 131, When the exciplex is formed by the exciplex material 131 and the host material 132, the exciplex is It is possible to efficiently extract light from both the complex and the guest material 131. The present inventors have found that

[0049] <Energy transfer mechanism> Here, we will explain the factors that govern the energy transfer process between molecules. The mechanisms of electron transfer are the Förster mechanism (dipole-dipole interaction) and the Dexter mechanism. Two mechanisms have been proposed: the first excited state (electron exchange interaction) and the second excited state (electron exchange interaction). Regarding the transfer of excitation energy from a material to a second material in the ground state, The energy transfer process between the molecules of the material in 2 is explained. The same is true in the case of

[0050] <Förster mechanism> In the Förster mechanism, the energy transfer does not require direct contact between molecules. Energy transfer occurs through the resonance phenomenon of the dipole vibration of a material and a second material. The first material transfers energy to the second material through the resonance phenomenon of the excitation current, and the first material The first material is in the ground state, and the second material in the ground state is in the excited state. The rate constant of the mechanism, k h*→g is shown in Equation (1).

[0051]

number

[0052] In formula (1), ν represents the frequency, and f' h (ν) is the normalized value of the first material The emission spectrum (or the fluorescence spectrum when discussing energy transfer from a singlet excited state) , and phosphorescence spectrum when discussing energy transfer from triplet excited states), and ε g ( ν) represents the molar extinction coefficient of the second material, N represents Avogadro's number, and n represents the refractive index of the medium. represents the refractive index, R represents the intermolecular distance between the first and second materials, and τ represents the measured excitation represents the lifetime of the state (fluorescence lifetime or phosphorescence lifetime), c represents the speed of light, and φ represents the luminescence quantum yield ( When discussing energy transfer from a singlet excited state, the fluorescence quantum yield is used. When discussing energy transfer from a triplet excited state, the fluorescence quantum yield is used. When discussing energy transfer, it stands for phosphorescence quantum yield, and K 2 is the first material and the second material is a coefficient (0 to 4) that represents the orientation of the transition dipole moment of the The match is K 2 =2 / 3.

[0053] <Dexter System> In the Dexter mechanism, the first and second materials overlap at a certain contact distance. Through the exchange of electrons from the first material in an excited state with those from the second material in the ground state, Energy transfer occurs. The rate constant for the Dexter mechanism is k h*→g is shown in formula (2). vinegar.

[0054]

number

[0055] In formula (2), h is the Planck constant, and K is a constant with the dimension of energy. where ν is the frequency and f' is the h (ν) is the normalized emission spectrum of the first material (When discussing energy transfer from a singlet excited state, the fluorescence spectrum and the triplet excited state are used.) When discussing energy transfer from the nucleophilic state, it represents the phosphorescence spectrum, and ε' g (ν) is the second represents the normalized absorption spectrum of the material, L represents the effective molecular radius, and R represents the first It represents the intermolecular distance between a material and a second material.

[0056] Here, the energy transfer efficiency from the first material to the second material, φ ET is expressed as formula (3). It will be done. r We discuss the emission process of the first material (energy transfer from the singlet excited state). The rate constants are expressed as follows: fluorescence in the case of a compound that is a triplet excited state, and phosphorescence in the case of a compound that is a triplet excited state. S, k n represents the rate constant of the non-radiative process (thermal deactivation and intersystem crossing) of the first material, and τ is the actual represents the lifetime of the excited state of the first material that is measured.

[0057]

number

[0058] From equation (3), the energy transfer efficiency φ ET To increase the rate of energy transfer, Degree constant k h*→g By increasing the other competing rate constants k r +k n (=1 / τ) is relatively It turns out that the smaller it is, the better.

[0059] <Excitation energy transfer to exciplex> First, consider the energy transfer via the Förster mechanism. Substituting equation (1) into equation (3), Therefore, in the case of the Förster mechanism, the energy Energy transfer efficiency φ ET does not depend on the lifetime τ of the excited state of the first material. Movement efficiency φ ET is the emission quantum yield φ (when considering energy transfer from a singlet excited state) is the fluorescence quantum yield, and when discussing energy transfer from the triplet excited state, is the phosphorescence quantum yield) It can be said that higher is better.

[0060] In addition, the emission spectrum of the first material (when discussing energy transfer from a singlet excited state) When discussing energy transfer from triplet excited states, we use the fluorescence spectrum. the absorption spectrum of the first material (corresponding to the transition from the singlet ground state to the singlet excited state) It is preferable that the molar absorption coefficient of the second material is high. This means that the emission spectrum of the first material is preferably the longest wavelength of the second material. This means that the absorption band that appears on the other side of the exciplex overlaps with that on the other side. In the case of Since direct transition to the excited state is forbidden, the molar extinction coefficient of the second material is negligible. This means that the excitation from the first material to the second material by the Förster mechanism The electromotive energy transfer process can be neglected.

[0061] Next, consider the energy transfer via the Dexter mechanism. According to equation (2), the rate constant is k h*→g To increase the emission spectrum of the first material (energy from the singlet excited state), When discussing energy transfer, consider the fluorescence spectrum, and when discussing energy transfer from triplet excited states. in the case of phosphorescence spectrum) and the absorption spectrum of the second material (singlet ground state to singlet excited state) It can be seen that it is better to have a larger overlap with the absorption corresponding to the transition to the The efficiency of energy transfer is optimized by matching the emission spectrum of the first material with the longest wavelength of the second material. This is achieved by overlapping the absorption band appearing on the long side of the second material. When an exciplex is used as a source, direct transition from the singlet ground state to the singlet excited state, and Since the direct transition from the singlet ground state to the triplet excited state is forbidden, the absorption of the second material is The absorption spectrum is negligible. This indicates that the first material is The excitation energy transfer process from the first material to the second material is negligible.

[0062] Therefore, when an exciplex is used as the second material, the first material is converted to the second material. The energy transfer process is related to both the Förster mechanism and the Dexter mechanism. No energy transfer occurs.

[0063] <Correlation between energy levels> In one embodiment of the present invention, the guest material 131 is preferably a phosphorescent compound. In the following description, a phosphorescent compound is used as the guest material 131. The guest material 131 may be interpreted as a phosphorescent compound.

[0064] The guest material 131 and the host material 132 in the light-emitting layer 130 form an exciplex. It is preferable that the combination forms

[0065] The combination of the guest material 131 and the host material 132 can form an exciplex. Any combination that can transport holes (hole transport properties) is acceptable. It is more preferable that the compound is a compound having a function of transporting electrons (electron transport property). In this case, a donor-acceptor type exciplex is easily formed, and In addition, the combination of the guest material 131 and the host material 132 can form an exciplex. The combination is a combination of a compound having a hole transporting property and a compound having an electron transporting property. In this case, the carrier balance can be easily controlled by the mixture ratio. In the present invention, the ratio of the compound having hole transporting properties to the compound having electron transporting properties is from 1:9 to 9:1 (by weight). In addition, by having this configuration, the carrier balance can be easily controlled. Therefore, the carrier recombination region can be easily controlled.

[0066] In addition, examples of the combination of a guest material and a host material that efficiently forms an exciplex include The HOMO (Highest Occ The highest occupied molecular orbital (HEOL) level is on the other hand The HOMO level is higher than the LUMO level (Lowest Unoccupied Mo The lowest unoccupied molecular orbital (LUMO) level is higher than the other LUMO level. High is preferable.

[0067] The LUMO and HOMO levels of the compounds were determined by cyclic voltammetry (C V) Derived from the electrochemical properties (reduction potential and oxidation potential) of the compound measured by the measurement It is possible.

[0068] For example, the guest material 131 has a hole transporting property and the host material 132 has an electron transporting property. In this case, the HOMO level of the guest material 131 is close to the HOMO level as shown in the energy band diagram in Figure 2(B). The LU level of the guest material 131 is preferably higher than the HOMO level of the host material 132. The MO level is preferably higher than the LUMO level of the host material 132. The energy difference between the HOMO level of the insulating material 131 and the HOMO level of the host material 132 is preferably It is preferably 0.1 eV or more, more preferably 0.2 eV or more, and further preferably The LUMO level of the guest material 131 and the LUMO level of the host material 132 are 0.3 eV or more. The energy difference from the LUMO level is preferably 0.1 eV or more, and more preferably 0 The energy difference is preferably 0.2 eV or more, and more preferably 0.3 eV or more. As a result, holes, which are carriers injected from a pair of electrodes (electrodes 101 and 102), and electrons are easily injected into the guest material 131 and the host material 132, respectively. This is preferable.

[0069] In FIG. 2B, Guest(131) represents the guest material 131, and Hos t(132) represents the host material 132, and ΔE G is the LUMO level of the guest material 131 and H It represents the energy difference with the OMO level, ΔE H1 is the LUMO level of the host material 132 and HO It represents the energy difference with the MO level, ΔE Ex is the LUMO level of the host material 132 and the guest These are notations and symbols that represent the energy difference from the HOMO level of the material 131.

[0070] In addition, the guest material 131 and the host material 132 form an exciplex. The host material 131 has a HOMO molecular orbital, and the host material 132 has a LUMO molecular orbital. The excitation energy of the exciplex is calculated based on the LUM of the host material 132. The energy difference between the O level and the HOMO level of the guest material 131 (ΔE Ex ) roughly corresponds to The energy difference between the LUMO level and the HOMO level of the guest material 131 (ΔE G ) and host The energy difference between the LUMO and HOMO levels of material 132 (ΔE H1 ) becomes smaller Therefore, by forming an exciplex between the guest material 131 and the host material 132, It is possible to form an excited state with smaller excitation energy than the above. Since it has an energy equivalent to a smaller excitation energy, it forms a stable excited state. It is possible.

[0071] In addition, the energy level of the guest material 131 and the host material 132 in the light-emitting layer 130 is The correlation between the positions is shown in Figure 2(C). The notations and symbols in Figure 2(C) are as follows: be. Guest (131): Guest material 131 (phosphorescent compound) ·Host(132): Host material 132 ·S G : S1 level of guest material 131 TG : T1 level of guest material 131 ·S H1 : S1 level of the host material 132 T H1 : T1 level of the host material 132 ·S E : S1 level of the exciplex T E :T1 level of the exciplex

[0072] In the light-emitting element of one embodiment of the present invention, the guest material 131 and the host material 132 contained in the light-emitting layer 130 The exciplex is formed with the cation material 132. The S1 level (S E ) and the T1 level of the exciplex Place(T E ) are adjacent energy levels (see route E1 in Figure 2(C)). .

[0073] An exciplex is an excited state consisting of two substances. In the case of photoexcitation, They are formed when one substance interacts with another substance that is in its ground state nearby. When the electrons return to the ground state by emitting light, the two electrons that formed the exciplex are released. The materials also behave as if they were separate entities. In the case of electrical excitation, one of them becomes excited. and quickly interacts with the nearby other to form an exciplex. The electron is absorbed by one atom and the hole is absorbed by the other atom, and the two interact to rapidly form an exciplex. The excited energy level of the exciplex (S E and T E ) forms an exciplex The S1 level (S G and S H1 ) Therefore, it is possible to form an excited state with a lower excitation energy. This allows the driving voltage of the light emitting element 150 to be reduced.

[0074] The S1 level of the exciplex (S E ) and T1 level (T E ) are adjacent energy levels Therefore, the exciplex has the function of exhibiting thermally activated delayed fluorescence. The energy is converted to singlet excitation energy by reverse intersystem crossing (upconversion). (See route E2 in FIG. 2(C)). A part of the triplet excitation energy is converted to singlet excitation energy by the exciplex. To do this, the S1 level of the exciplex (S E ) and T1 level (T E ) energy difference is 0 eV It is preferable that the value is larger than 0.2 eV or less, and it is preferable that the value is larger than 0 eV or less and is smaller than 0.1 eV. It is more preferable to efficiently generate reverse intersystem crossing by increasing the T1 level of the exciplex ( T E ) is the T of each substance (guest material 131 and host material 132) that forms an exciplex. 1 level (T G and T H1 ) is preferably lower than that of the guest material 131. In addition, the triplet excitation energy of the exciplex is less likely to be quenched by the host material 132. This allows efficient reverse intersystem crossing to occur.

[0075] In addition, exciplexes exist only in excited states, and the excited energy levels of exciplexes (S E and T E ) is an energy level that exists only when an exciplex is formed, so The excitation state of each material (guest material 131 and host material 132) that forms the complex is excited from the ground state. There is no direct transition to the excited state of the complex. Gee level (SG and T G ) or the excitation energy level of the host material 132 alone (S H1 Reach BiT H1 ) to the excited energy level of the exciplex (S E and T E ) of the excitation energy Therefore, the generation of an exciplex between the guest material 131 and the host material 132 is confirmed. By appropriately controlling the efficiency, the light emission from the exciplex and the light emission from the guest material 131 can be obtained. , and it becomes possible to efficiently extract both.

[0076] To achieve this, the T1 level (T H1 ) is the T1 equivalent of guest material 131 Place(T G ) or more. In addition, the T1 level (T G ) is a guess The T1 level (T E ) or more In this way, an exciplex formed between the guest material 131 and the host material 132 is preferably The excited energy of the triplet is efficiently quenched by the exciplex. Reverse intersystem crossing from the ionized energy to the singlet excitation energy, and then the singlet excitation energy Furthermore, as described above, the excitation of the guest material 131 can be suppressed. Since energy quenching is also less likely to occur, light emission from the guest material 131 can be obtained efficiently. It becomes possible.

[0077] In addition, when the direct recombination process of carriers becomes dominant in the guest material 131, The process of forming an exciplex between the material 131 and the host material 132 is less likely to occur. In the guest material 131, the carriers recombine directly and undergo the formation of an exciplex. The energy transfer process (Routes E1 and E2 in Figure 2(C)) and both processes have the desired probability For this purpose, it is preferable that the weight ratio of the host material 132 and the guest material 131 is The weight ratio of the guest material 131 is preferably low, and more specifically, the weight ratio of the host material 132 is preferably low. The weight ratio of the guest material 131 to the total amount of the cations is preferably 0.01 to 0.5, more preferably Preferably, it is 0.05 or more and 0.3 or less.

[0078] The light emitted from the guest material 131 and the excitation light generated between the guest material 131 and the host material 132 are By extracting the light emitted from the complex in the desired ratio, the color of the light emitted by the light-emitting element can be controlled. For example, it is possible to control the color of light emitted by the light-emitting element to white or a color close to white. The light emitted from the guest material 131 and the light emitted from the guest material 131 and the host material 132 are The ratio of the light emitted from the exciplex to be formed can be adjusted. Specifically, Emission from 1: Emission from an exciplex formed between a guest material 131 and a host material 132= The range of 1:9 to 9:1 is preferred, and the range of 1:5 to 5:1 is more preferred. The light emitted by the optical element may include light emission other than these lights.

[0079] The guest material 131 has an electron transporting property, and the host material 132 has a hole transporting property. In that case, as shown in the energy band diagram of FIG. Preferably, the HOMO level of material 132 is higher than the HOMO level of guest material 131; It is preferred that the LUMO level of the host material 132 is higher than the LUMO level of the guest material 131. It is nice.

[0080] <Light Emitting Mechanism of Light Emitting Device 2> Next, a configuration example different from that of the light-emitting layer shown in FIG. 2(A) will be described below with reference to FIG. 3(A). Make a statement.

[0081] FIG. 3(A) is a schematic cross-sectional view showing an example of the light-emitting layer 130 shown in FIG. The light-emitting layer 130 shown includes a guest material 131, a host material 132, and a host material 133. has.

[0082] In the light-emitting layer 130, the host material 132 or the host material 133 is present in the largest amount by weight. The guest material 131 is dispersed in the host material 132 or the host material 133 . Here, the guest material 131 is preferably a phosphorescent compound. and the host material 132 are preferably a combination that forms an exciplex.

[0083] In addition, the combination of the host material that efficiently forms an exciplex is the guest material 13. The HOMO level of either the emissive material 131 or the host material 132 is the highest among the materials in the emissive layer 130. The HOMO level is the lowest among the materials in the light-emitting layer 130, and the other LUMO level is the lowest among the materials in the light-emitting layer 130. In other words, it is preferable that one of the guest material 131 and the host material 132 has an O level. The HOMO level of one of the two is higher than the HOMO level of the other and the HOMO level of the host material 133. , the LUMO level of the other is higher than the LUMO level of the other and the LUMO level of the host material 133. In this way, the host material 132 and the host material 133 can easily undergo excitocoupling. It can suppress the reactions that build the body.

[0084] For example, the guest material 131 has a hole transporting property and the host material 132 has an electron transporting property. In this case, the HOMO level of the guest material 131 is close to that of the guest material 131 as shown in the energy band diagram in Figure 3(B). The HOMO level of the host material 132 is higher than the HOMO level of the host material 133. It is preferable that the LUMO level of the host material 132 is the same as the LUMO level of the guest material 131 and It is preferable that the LUMO level of the host material 133 is lower than that of the host material 13. The LUMO level of 3 may be higher or lower than the LUMO level of the guest material 131. The HOMO level of the host material 133 is higher or lower than the HOMO level of the host material 132. It's okay.

[0085] In FIG. 3B, Guest(131) represents the guest material 131, and Hos t(132) represents the host material 132, and Host(133) represents the host material 133. , ΔE G represents the energy difference between the LUMO level and the HOMO level of the guest material 131, and Δ E H1 represents the energy difference between the LUMO level and the HOMO level of the host material 132, and ΔE H2 represents the energy difference between the LUMO level and the HOMO level of the host material 133, and ΔE E x is the energy between the LUMO level of the host material 132 and the HOMO level of the guest material 131. The notation and sign that represent the difference.

[0086] At this time, the guest material 131 and the host material 132 form an excited electron complex. The energy is the energy between the LUMO level of the host material 132 and the HOMO level of the guest material 131. Energy difference (ΔE Ex ) and the LUMO and HOMO levels of the host material 133 The energy difference (ΔE H2 ) is preferably smaller than

[0087] In the light-emitting layer 130 shown in FIG. 3(A), a guest material 131, a host material 132, and a The correlation between the energy levels of the SiO2-based material and the SiO2-based material 133 is shown in FIG. The notations and symbols used are as follows: Guest (131): Guest material 131 (phosphorescent compound) ·Host(132): Host material 132 ·Host(133): Host material 133 ·S G : S1 level of guest material 131 T G : T1 level of guest material 131 ·S H1 : S1 level of the host material 132 T H1 : T1 level of the host material 132 ·S H2 : S1 level of the host material 133 T H2 : T1 level of the host material 133 ·S E : S1 level of the exciplex T E :T1 level of the exciplex

[0088] In the light-emitting element of one embodiment of the present invention, the guest material 131 and the host material 132 contained in the light-emitting layer 130 The exciplex is formed with the cation material 132. The S1 level (S E ) and the T1 level of the exciplex Place(T E ) are adjacent energy levels (see route E1 in Figure 3(C)). .

[0089] The T1 level of the host material 132 (T H1 ) and the T1 level of the host material 133 (T H2 ) is the T1 level (T G ) or more. In addition, the guest material 13 T1 level of 1 (T G) is an exciplex formed by a guest material 131 and a host material 132. T1 level (T E ) or more. By doing so, the guest material 131 and the host material The excitation energy of the exciplex formed with the material 132 is hardly quenched, and the exciplex By this, reverse intersystem crossing from triplet excitation energy to singlet excitation energy can be efficiently achieved, and It is then possible to obtain light emission from the subsequent singlet excitation energy. Since the excitation energy of the guest material 131 is less likely to be quenched, the guest material 131 can be efficiently quenched. It is possible to obtain good light emission.

[0090] In addition, when the direct recombination process of carriers becomes dominant in the guest material 131, The process of forming an exciplex between the material 131 and the host material 132 is less likely to occur. In the guest material 131, the carriers recombine directly and undergo the formation of an exciplex. The energy transfer process (Routes E1 and E2 in Figure 3(C)) and both processes have the desired probability. For this purpose, the light-emitting layer 130 is preferably formed of a guest material 131 and a host material 132. It is preferable to add a material other than the guest material 132 to the light-emitting layer 130. By using the host material 133 in addition to the host material 132 and the guest material 131, The probability of generating an exciplex between the host material 132 and the cation can be appropriately controlled. The weight ratio of the total amount of the guest material 131 and the host material 132 is It is preferable that the weight ratio of the host material 131 is low. Specifically, the weight ratio of the host material 132 and the host material 13 The weight ratio of the guest material 131 to the total amount of the three is preferably 0.01 or more and 0.5 or less. More preferably, it is 0.05 or more and 0.3 or less.

[0091] The guest material 131 has an electron transporting property, and the host material 132 has a hole transporting property. In that case, as shown in the energy band diagram of FIG. The HOMO level of the material 132 is the same as the HOMO level of the guest material 131 and the HOMO level of the host material 133. The LUMO level of the guest material 131 is preferably higher than the HOMO level of the host material 1 It is preferable that the LUMO level of the compound is lower than the LUMO level of the host material 133. In this case, the LUMO level of the host material 133 is higher than the LUMO level of the host material 132. The HOMO level of the host material 133 may be higher or lower than that of the guest material 131. It may be higher or lower than the MO level.

[0092] <Material> Next, components of a light-emitting element according to one embodiment of the present invention will be described in detail below.

[0093] <Light-emitting layer> The materials that can be used for the light-emitting layer 130 are described below.

[0094] The guest material 131 and the host material 132 are a combination that forms an exciplex with each other. As long as the two are combined, there is no particular limitation, but one of them has a function of transporting electrons and the other has a function of transporting holes. It is preferable that the ion exchange resin has a function of

[0095] When the host material 132 has a hole transporting function, the host material 132 has an excess of π electrons. It is preferred that the aryl group has at least one of a heteroaromatic skeleton or an aromatic amine skeleton.

[0096] The π-electron-rich heteroaromatic skeleton of the host material 132 may be a furan skeleton, a thiophene skeleton, or a cyclohexane skeleton. Since the phenylene skeleton and the pyrrole skeleton are stable and reliable, it is preferable to select from these skeletons. It is preferable that the furan skeleton has one or more of the above. As the thiophene skeleton, a dibenzothiophene skeleton is preferable. As the pyrrole skeleton, an indole skeleton or a carbazole skeleton is preferable. Particularly preferred is a phenyl-9H-carbazol-3-yl)-9H-carbazole skeleton. These skeletons may have a substituent.

[0097] In addition, the aromatic amine skeleton of the host material 132 does not have an NH bond. A tertiary amine is preferred, and a triarylamine skeleton is particularly preferred. The aryl group having the aryl skeleton is a substituted or unsubstituted aryl group having 6 to 13 carbon atoms forming a ring. Preferred are aryl groups, such as a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, etc. Examples of the alkyl group include an aryl group and a triphenylenyl group.

[0098] The structures having π-electron-rich heteroaromatic skeletons and aromatic amine skeletons have excellent hole transport properties. It is particularly preferred because it is stable and has good reliability. For example, a carbazole skeleton and an aryl skeleton are preferred. Examples of such structures include those having a diamine skeleton.

[0099] The above-mentioned π-electron-rich heteroaromatic skeleton and aromatic amine skeleton include, for example, the following: Examples of the skeletons are represented by the general formulae (101) to (117). X in (117) represents an oxygen atom or a sulfur atom.

[0100] [ka]

[0101] Alternatively, when the host material 132 has an electron transport function, the host material 132 is π It is preferable that the compound has an electron-deficient heteroaromatic skeleton. Examples of the π-electron-deficient heteroaromatic skeleton include: Pyridine skeleton, diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), and A triazine skeleton is preferred, and among them, a diazine skeleton or a triazine skeleton is stable and reliable. It is good and therefore preferred.

[0102] The π-electron deficient heteroaromatic skeleton may be, for example, a compound represented by the following general formula (201) to (2 18). In addition, X in the general formulae (209) to (211) is Represents an oxygen atom or a sulfur atom.

[0103] [ka]

[0104] In addition, a skeleton having hole transport properties (specifically, a π-electron-rich heteroaromatic skeleton and an aromatic At least one of the amine skeletons) and a skeleton having electron transport properties (specifically, a π-electron deficient complex A compound in which the aromatic ring structure is bonded directly or via an arylene group may also be used. Examples of the arylene group include a phenylene group, a biphenyldiyl group, and a naphthyl group. Examples thereof include a lendiyl group and a fluorenediyl group.

[0105] As a linking group for linking the skeleton having hole transporting property and the skeleton having electron transporting property, Examples of the skeleton include those represented by the following general formulas (301) to (315).

[0106] [ka]

[0107] The aromatic amine skeleton (specifically, for example, a triarylamine skeleton), π-electron excess Heteroaromatic skeletons (specifically, for example, furan skeletons, thiophene skeletons, pyrrole skeletons) a ring having a π-electron deficient heteroaromatic skeleton (specifically, for example, a diazine skeleton or a triazine skeleton) A ring having a skeleton), or the above general formulae (101) to (117), general formula (201) To (218) and general formulae (301) to (315) may have a substituent. The substituent is preferably an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a cycloalkyl group having 3 to 6 carbon atoms. or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms. Specific examples of the alkyl group having 1 to 6 carbon atoms include For example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group , tert-butyl group, n-hexyl group, etc. Specific examples of the cycloalkyl group having 6 carbon atoms include a cyclopropyl group, a cyclobutene group, and a cyclobutene group. Examples of the alkyl group include cyclohexyl, cyclopentyl, and cyclohexyl. Examples of the aryl group having 6 to 12 carbon atoms include a substituted or unsubstituted phenyl group, a naphthyl group, and the like. Specific examples of the substituents include a phenyl group, a phenyl group, and the like. Such an example is, for example, a fluorene skeleton. When the carbon atom at position 9 has two phenyl groups as substituents, the phenyl groups are bonded to each other. In some cases, a spirofluorene skeleton is formed by the addition of an unsubstituted fluorene. In the case of conversion, it is advantageous in terms of ease of synthesis and the cost of raw materials.

[0108] In addition, Ar represents a single bond or an arylene group having 6 to 13 carbon atoms. The benzene group may have substituents, and the substituents may be bonded to each other to form a ring. An example of such a compound is a fluorenyl group having a phenyl group as a substituent at the 9-position carbon. The two phenyl groups are bonded together to form a spirofluorene skeleton. Examples of the arylene group having 6 to 13 carbon atoms include the following: Phenylene group, naphthalenediyl group, biphenyldiyl group, fluorenediyl group, etc. In addition, when the arylene group has a substituent, the substituent Examples of the group include an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and A C6 to C12 aryl group or an aryl group can also be selected as a substituent. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group and an ethyl group. , propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-hexane In addition, cycloalkyl groups having 3 to 6 carbon atoms and Specific examples of the cycloalkyl include cyclopropyl, cyclobutyl, cyclopentyl, and cyclopentyl groups. In addition, aryl groups having 6 to 12 carbon atoms can be given as examples. Specific examples of the alkyl group include a phenyl group, a naphthyl group, and a biphenyl group. This can be done.

[0109] The arylene group represented by Ar is, for example, the following structural formula (Ar-1) to (Ar- 18) can be used. The groups that can be used as Ar are Not limited to these.

[0110] [ka]

[0111] Also, R 1 and R 2 each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; a cycloalkyl group having 3 to 6 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 6 to 13 carbon atoms; represents an unsubstituted aryl group. Examples of the alkyl group having 1 to 6 carbon atoms include Specifically, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isopropyl group, butyl group, tert-butyl group, n-hexyl group, etc. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group. Examples of the aryl group include cyclobutyl, cyclopentyl, and cyclohexyl groups. Examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, Specific examples include a biphenyl group and a fluorenyl group. The aryl group and the phenyl group may have a substituent, and the substituents may be bonded to each other to form a ring. The substituent may be an alkyl group having 1 to 6 carbon atoms, a group having 3 or more carbon atoms, or a group having 4 to 6 carbon atoms. Cycloalkyl groups having up to 6 carbon atoms and aryl groups having from 6 to 12 carbon atoms are also usable as substituents. Specific examples of the alkyl group having 1 to 6 carbon atoms include: For example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t Examples of the alkyl group include an ethyl group, an n-butyl group, and an n-hexyl group. Specific examples of the cycloalkyl group having a number of 6 include a cyclopropyl group and a cyclobutyl group. Examples of the aryl group include cyclopentyl and cyclohexyl groups. Examples of the aryl group having up to 12 carbon atoms include a phenyl group, a naphthyl group, and a biphenyl group. The following are some concrete examples:

[0112] Also, R 1 and R 2 The alkyl group or aryl group represented by the following structural formula ( Groups represented by R-1) to (R-29) can be used. The groups that can be used as the aryl group are not limited to these.

[0113] [ka]

[0114] In addition, the general formulae (101) to (117), (201) to (218), and ( 301) to (315), and Ar, R 1 and R 2 The substituents which may be substituted include, for example, For example, the alkyl group or aryl group represented by the above structural formulas (R-1) to (R-24) may be used. The alkyl or aryl group can be selected from the group consisting of: Not limited to these.

[0115] As the host material 132, for example, the following hole transporting material and electron transporting material are used. It is possible.

[0116] As the hole transporting material, a material having a higher hole transporting property than an electron transporting property can be used. ×10 -6 cm 2 It is preferable that the material has a hole mobility of 1 / Vs or more. The hole transporting material may be an aromatic amine, a carbazole derivative, or the like. The material may be a polymer.

[0117] As examples of materials with high hole transport properties, aromatic amine compounds include N,N' -Di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDP PA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino ]biphenyl (abbreviation: DPAB), N,N'-bis{4-[bis(3-methylphenyl) Amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-di Amine (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl Examples include]-N-phenylamino]benzene (abbreviation: DPA3B).

[0118] 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) etc. can be mentioned.

[0119] Another example of a carbazole derivative is 4,4'-di(N-carbazolyl)biphene. Nyl (abbreviation: CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzoyl Zene (abbreviation: TCPB), 1,4-bis[4-(N-carbazolyl)phenyl]-2,3 , 5,6-tetraphenylbenzene, etc. can be used.

[0120] As a material with high hole transport properties, for example, 4,4'-bis[N-(1-naphthyl )-N-phenylamino]biphenyl (abbreviation: NPB or α-NPD) and N,N'-biphenyl S(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-naphthalene 1'-TNATA, 4,4'-N-phenylamino]triphenylamine ,4''-Tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA ), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino] Triphenylamine (abbreviation: m-MTDATA), 4,4'-bis[N-(spiro-9,9 '-Bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4-Phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation :BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)trifluoroacetate mBPAFLP, N-(9,9-dimethyl-9H-fluorene- 2-yl)-N-{9,9-dimethyl-2-[N'-phenyl-N'-(9,9-dimethyl (amino)-9H-fluoren-7-yl}phenyl DFLADFL, N-(9,9-dimethyl-2-diphenylamino-9H -fluoren-7-yl)diphenylamine (abbreviation: DPNF), 2-[N-(4-difluorophenyl) (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: PCBBi1 BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl ) Triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4'' -(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCB NBB), 4-phenyldiphenyl-(9-phenyl-9H-carbazol-3-yl) Amine (abbreviation: PCA1BP), N,N'-bis(9-phenylcarbazol-3-yl) )-N,N'-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N,N' ,N''-Triphenyl-N,N',N''-tris(9-phenylcarbazole-3- N-(4-biphenylyl)benzene-1,3,5-triamine (abbreviation: PCA3B) )-N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-carbazone PCBiF, N-(1,1'-biphenyl-4-yl) )-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9- Dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF), 9,9-dimethyl- N-Phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl] Fluorene-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl 9,9'-bifluorene-2-yl-9H-carbazol-3-ylphenyl Amine (abbreviation: PCBASF), 2-[N-(9-phenylcarbazol-3-yl)- N-phenylamino]spiro-9,9'-bifluorene (abbreviation: PCASF), 2,7- Bis[N-(4-diphenylaminophenyl)-N-phenylamino]-spiro-9,9 '-Bifluorene (abbreviation: DPA2SF), N-[4-(9H-carbazol-9-yl )phenyl]-N-(4-phenyl)phenylaniline (abbreviation: YGA1BP), N,N '-Bis[4-(carbazol-9-yl)phenyl]-N,N'-diphenyl-9,9 -Dimethylfluorene-2,7-diamine (abbreviation: YGA2F) and other aromatic amine compounds Also usable are 3-[4-(1-naphthyl)-phenyl]-9-phenyl. PCPN, 3-[4-(9-phenanthryl)- phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPPn), 3,3'-bis( 9-phenyl-9H-carbazole) (abbreviation: PCCP), 1,3-bis(N-carbazo mCP, 3,6-bis(3,5-diphenylphenyl)-9- Phenylcarbazole (abbreviation: CzTP), 4-{3-[3-(9-phenyl-9H- mmDBFFLBi -II), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) DBF3P-II, 1,3,5-tri(dibenzothiophene-4-yl) -Benzene (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl [Dibenzothiophene (abbreviation: DBTFLP)] -III), 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6 -Phenyldibenzothiophene (abbreviation: DBTFLP-IV), 4-[3-(triphenyl (2-phenyl)dibenzothiophene (abbreviation: mDBTPTp-II) Mine compounds, carbazole compounds, thiophene compounds, furan compounds, fluorene compounds , triphenylene compounds, phenanthrene compounds, etc. can be used. The substance is mainly 1×10 -6 cm 2 A material that has a hole mobility of 1000V or more. Any other substance may be used as long as it has a higher hole transporting property than electron transporting property.

[0121] As the electron transport material, a material having a higher electron transporting property than a hole transporting property can be used. ×10 -6 cm 2 It is preferable that the material has an electron mobility of 1 / Vs or more. Materials that are easy to absorb (materials with electron transport properties) include gold with zinc or aluminum. The use of π-electron-deficient heteroaromatic compounds such as heteroaromatic complexes and nitrogen-containing heteroaromatic compounds The metal complexes include quinoline ligands, benzoquinoline ligands, oxazo ligands, and the like. Metal complexes having aryl or thiazole ligands are also known. Heteroaromatic compounds include oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, and phenylene oxide derivatives. Loline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, triazine derivatives The body, etc.

[0122] For example, tris(8-quinolinolato)aluminum(III) (abbreviation: Alq), tri Bis(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq3), BeBq2 ), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum ( III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq) Metal complexes having a quinoline skeleton or a benzoquinoline skeleton, etc. Bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO) , Bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ) Metal complexes having oxazole or thiazole ligands such as In addition to metal complexes, 2-(4-biphenylyl)-5-(4-tert-butyl phenyl)-1,3,4-oxadiazole (abbreviation: PBD) and 1,3-bis[5-( p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazole-2 -yl)phenyl]-9H-carbazole (abbreviation: CO11), 3-(4-biphenylyl) )-4-Phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 2,2',2''-(1,3,5-benzenetriyl)tris(1- Phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothio mD BTBIm-II), bathophenanthroline (abbreviation: BPhen), bathocuproine ( Abbreviation: BCP), 2,9-bis(naphthalene-2-yl)-4,7-diphenyl-1,1 Heterocyclic compounds such as 0-phenanthroline (abbreviation: NBPhen) and 2-[3-(dibenzyl) 2mD BTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3 -yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2- [3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h] Quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H- Carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzP DBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[ f,h]quinoxaline (abbreviation: 7mDBTPDBq-II) and 6-[3-(dibenzo 6mDibenzo[f,h]quinoxaline (abbreviation: 6mDB TPDBq-II), 4,6-bis[3-(phenanthren-9-yl)phenyl]pyridine 4,6mPnP2Pm, 4,6-bis[3-(4-dibenzothienyl) phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-( 9H-Carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm) Heterocyclic compounds with diazine skeletons such as 2-{4-[3-(N-phenyl-9H- Carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl Phenyl-1,3,5-triazine (abbreviation: PCCzPTzn) and other compounds with triazine skeletons Heterocyclic compounds such as 3,5-bis[3-(9H-carbazol-9-yl)phenyl] Pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridyl)phenyl Heterocyclic compounds with pyridine skeletons such as 4,4 '-Bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs) Any heteroaromatic compound can be used. Also, poly(2,5-pyridinediyl) ( Abbreviation: PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-( pyridine-3,5-diyl)] (abbreviation: PF-Py), poly[(9,9-dioctylfulv oren-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)](abbreviation Polymeric compounds such as PF-BPy can also be used. Mainly 1×10 -6 cm 2 / Vs or higher. Any substance other than the above may be used as long as it has a high electron transporting property.

[0123] The guest material 131 is preferably one having a function of converting triplet excitation energy into luminescence. When the guest material 131 has a heavy metal, spin-orbit interaction (electron spin angle The interaction between the orbital momentum and the orbital angular momentum promotes intersystem crossing between the singlet and triplet states. Since the guest material 131 is driven by the singlet ground state and the triplet excited state, That is, the transition between the singlet ground state and the triplet excited state of the guest material 131 is allowed. The efficiency of the emission and the probability of absorption related to the transition can be increased. The material 131 preferably contains a metal element having a large spin-orbit coupling, and in particular, a platinum group element. (Ruthenium (Ru), Rhodium (Rh), Palladium (Pd), Osmium (Os), It is preferable to have iridium (Ir) or platinum (Pt), among which iridium By having This can be increased, which is preferable.

[0124] The guest material 131 (phosphorescent compound) is iridium, rhodium, or white. Gold-based organometallic complexes or metal complexes are also examples. Among them, organic iridium complexes, such as iridium complexes, The orthometalated ligand is preferably a 4H-triazolium complex. 1H-triazole ligands, 1H-triazole ligands, imidazole ligands, pyridine ligands, pyrimidine ligands Examples of the ligand include a pyrazine ligand, a pyrazine ligand, and an isoquinoline ligand. , guest material 131 (phosphorescent compound) is triplet MLCT (Metal to Ligan). d Charge Transfer (Cat 1+Cat 2+) transition absorption band.

[0125] Examples of substances having a blue or green emission peak include tris{2-[5-(2 -methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazo {3-yl-κN2]phenyl-κC}iridium(III) (abbreviation: Ir(mpp tz-dmp)3), tris(5-methyl-3,4-diphenyl-4H-1,2,4-tris( riazolate)iridium(III) (abbreviation: Ir(Mptz)3), tris[4-(3- Biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]i Iridium(III) (abbreviation: Ir(iPrptz-3b)3), tris[3-(5-biphenyl] (phenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]irid Ir(III) (abbreviation: Ir(iPr5btz)3), a 4H-triazole skeleton and organometallic iridium complexes having tris[3-methyl-1-(2-methylphenyl) -5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: Ir (Mptz1-mp)3), tris(1-methyl-5-phenyl-3-propyl-1H- 1,2,4-Triazolate)iridium(III) (abbreviation: Ir(Prptz1-Me) 3) and fac-triazole-based organometallic iridium complexes. S[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole] Iridium(III) (abbreviation: Ir(iPrpmi)3), tris[3-(2,6-dimethyl phenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(I II) Imidazole skeleton-containing compounds such as Ir(dmpimpt-Me)3 Organic metal iridium complexes and bis[2-(4',6'-difluorophenyl)pyridinato N,C 2’ ]Iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation: FI r6), Bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ]Ili Dium(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis (Trifluoromethyl)phenyl]pyridinato-N,C 2’}Iridium(III) pico Ir(CF3ppy)2(pic) (fluorophenyl)pyridinato-N,C 2’ ]Iridium(III) acetylacetonate (abbreviation: FIr(acac)) Among the above, 4H-triazole is an organometallic iridium complex. Nitrogen-containing five-membered heterocyclic skeletons such as 1H-triazole skeleton and imidazole skeleton The organometallic iridium complex has high triplet excitation energy and is highly reliable and has excellent luminescence efficiency. It is particularly preferred because it is also excellent in

[0126] In addition, examples of substances having a green or yellow emission peak include tris(4-methylphenyl) Ir(mppm)3, Tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: I r(tBuppm)3), (acetylacetonato)bis(6-methyl-4-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)( Abbreviation: Ir(dppm)2(acac) (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazine) Iridium(III) (abbreviation: Ir(mppr-Me)2(acac)), (acetylacetonate arylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinate)irid Pyrazine skeleton 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-difluorophenyl) and Venyl-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, the organometallic iridium complexes having a pyrimidine skeleton are Dium complexes are particularly preferred because they are remarkably excellent in reliability and luminous efficiency.

[0127] 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(naphthalene-1-yl)pyrimidinyl] Nato](dipivaloylmethanato)iridium(III) (abbreviation: Ir(d1npm)2( Organometallic iridium complexes with pyrimidine skeletons such as (acetylacetamide) Iridium(III) r(tppr)2(acac)), bis(2,3,5-triphenylpyrazine)(dipyridine) 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))(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 extremely reliable and have excellent luminous efficiency. In addition, organometallic iridium complexes with pyrazine skeletons can emit red light with good chromaticity. can be done.

[0128] In addition, materials that can be used as the host material 133 in the light-emitting layer 130 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), and other 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 Zene (abbreviation: OXD-7), 3-(4-biphenylyl)-4-phenyl-5-(4-tetraphenyl) 2,2',2' rt-Butylphenyl)-1,2,4-triazole (abbreviation: TAZ) '-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazo 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 (abbreviation: NPB or 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 bis(phenylene phosphate phosphate) and bis(phenylene phosphate phosphate). 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-anth 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)triphenyl YGAPA, N,9-diphenyl-N-[4-(10-phenyl-9 -anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), ,9-diphenyl-N-{4-[4-(10-phenyl-9-anthryl)phenyl]furan N,9-diphenyl}-9H-carbazol-3-amine (abbreviation: PCAPBA), 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 Ben-3,3'-diyl)diphenanthrene (abbreviation: DPNS), 9,9'-(stilbe 3,3',3''-(phenyl-4,4'-diyl)diphenanthrene (abbreviation: DPNS2), Benzene-1,3,5-triyl)tripylene (abbreviation: TPB3) In addition, among these and known substances, the energy gap of the guest material 131 can be By selecting and using one or more materials with an energy gap larger than that of the good.

[0129] The light-emitting layer 130 may be formed of two or more layers. When the light-emitting layer 130 is formed by laminating the first light-emitting layer and the second light-emitting layer in this order from the hole transport layer side, A substance having a hole transporting property is used as a host material for the first light-emitting layer, and a substance having a hole transporting property 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 insulating film.

[0130] In the light-emitting layer 130, a guest material 131, a host material 132, and a host material It may contain materials other than 133.

[0131] A fluorescent compound may be used in the light-emitting layer 130. The fluorescent compound is not particularly limited. However, anthracene derivatives, tetracene derivatives, chrysene derivatives, and phenanthrene derivatives Conductors, pyrene derivatives, perylene derivatives, stilbene derivatives, acridone derivatives, coumarin Derivatives, phenoxazine derivatives, phenothiazine derivatives, etc. are preferred.

[0132] Specifically, 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2 ,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl -9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2 BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoro 1,6-Pyrene-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn) , N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H -fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMem FLPAPrn), N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl )phenyl]-N,N'-bis(4-tert-butylphenyl)pyrene-1,6-diazo 1,6tBu-FLPAPrn, N,N'-bis[4-(9-phenyl- 9H-Fluoren-9-yl)phenyl]-N,N'-diphenyl-3,8-dicyclohexyl Xylpyrene-1,6-diamine (abbreviation: ch-1,6FLPAPrn), N,N'-biphenyl S[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbe YGA2S, 4-(9H-carbazol-9-yl) -4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA) , 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-anthracene N,9-diphenyl-N-[4- (10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation Name: PCAPA), Perylene, 2,5,8,11-tetra(tert-butyl)perylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl- 9H-Carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), N,N' '-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene) Bis[N,N',N'-triphenyl-1,4-phenylenediamine] (abbreviation: DPAB PA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl] 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-2,7,10 ,15-Tetraamine (abbreviation: DBC1), Coumarin 30, N-(9,10-diphenyl -2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2 PCAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthracene aryl]-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPh A), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl -1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(1,1 '-biphenyl-2-yl)-2-anthryl]-N,N',N'-triphenyl-1, 4-Phenylenediamine (abbreviation: 2DPABPhA), 9,10-bis(1,1'-biphenyl) phenyl-2-yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N- Phenylanthracene-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenyl Dianthracene-9-amine (abbreviation: DPhAPhA), Coumarin 6, Coumarin 545T , N,N'-diphenylquinacridone (abbreviation: DPQd), rubrene, 2,8-di-te rt-Butyl-5,11-bis(4-tert-butylphenyl)-6,12-diphenyl Tetrathracene (abbreviation: TBRb), Nile Red, 5,12-bis(1,1'-biphenyl) 2-(2-(2-phenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), [4-(Dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-yl 2-(2-methyl-6-[2-(2,3-dimethylphenyl)propanedinitrile (abbreviation: DCM1), ,6,7-Tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl ]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N ',N'-Tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methyl phenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: p -mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl 2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl )Ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI) , 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3, 6,7-Tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl] -4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2, 6-Bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-yl 2-{2,6-bis[2-(8- Methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H -benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}p Dopanedinitrile (abbreviation: BisDCJTM), 5,10,15,20-tetraphenyl Bisbenzo[5,6]indeno[1,2,3-cd:1',2',3'-lm]perylene , etc.

[0133] As the guest material 131, triplet excitation energy is converted to singlet excitation energy. Any material that has the function of converting triplet excitation energy into singlet excitation energy can be used. In addition to phosphorescent compounds, thermally activated delayed fluorescent materials are also examples of materials that have the function of converting light. Therefore, the part described as a phosphorescent compound is considered to be a thermally activated delayed fluorescent material. In addition, the conditions for efficient thermally activated delayed fluorescence are as follows: The energy difference between the T1 level and the T2 level is preferably greater than 0 eV and less than or equal to 0.2 eV, and more preferably Preferably, the value is greater than 0 eV and equal to or less than 0.1 eV.

[0134] In addition, materials that exhibit thermally activated delayed fluorescence can be synthesized by themselves through reverse intersystem crossing from a triplet excited state. The thermally activated delayed fluorescent material may be a material capable of generating a doublet excited state. When the substrate is made of, for example, the following materials can be used:

[0135] 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. Can be obtained.

[0136] In addition, as a thermally activated delayed fluorescent material composed of one kind of material, π-electron-rich heteroaromatic Heterocyclic compounds having an aromatic skeleton and a π-electron deficient heteroaromatic skeleton can also be used. Specifically, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[ 2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-T RZ), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-3-yl 4,6-diphenyl-1,3,5-triazine (abbreviation Name: PCCzPTzn), 2-[4-(10H-phenoxazin-10-yl)phenyl ]-4,6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3-[4 -(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5- Diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-di Methyl-9H-acridin-10-yl)-9H-xanthen-9-one (abbreviation: ACR XTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl] Sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10'H-spiro[a Clizin-9,9'-anthracene]-10'-one (abbreviation: ACRSA) and the like. The heterocyclic compound has a π-electron rich heteroaromatic skeleton and a π-electron deficient heteroaromatic skeleton. Since the π-electron-rich heteroaromatic aromatic compound has a high electron transporting property and a high hole transporting property, it is preferable. A substance in which an aromatic skeleton and a π-electron-deficient heteroaromatic skeleton are directly bonded is called a π-electron-rich heteroaromatic compound. The donor property of the skeleton and the acceptor property of the π-electron-deficient heteroaromatic skeleton are both strong, and the S1 level and This is particularly preferred since the difference in T1 level becomes smaller.

[0137] The electrode 101 and the electrode 102 have a function of injecting holes and electrons into the light-emitting layer 130. The electrodes 101 and 102 are made of metals, alloys, conductive compounds, and mixtures or laminates thereof. The metal can be aluminum (Al) as a typical example. , and other transition metals such as silver (Ag), tungsten, chromium, molybdenum, copper, and titanium. , alkali metals such as lithium (Li) and cesium, calcium, magnesium (Mg) Group 2 metals such as ytterbium (Yb) can be used as transition metals. A rare earth metal may be used. As the alloy, an alloy containing the above metals may be used. Examples of the conductive compound include MgAg and AlLi. Indium tin oxide (ITO), silicon or silicon oxide Including indium tin oxide (abbreviation: ITSO), indium zinc oxide (Indium Z inc Oxide), tungsten and zinc-containing indium oxide, etc. As the conductive compound, an inorganic carbon-based material such as graphene may be used. As described above, electrodes 101 and 10 are formed by stacking multiple layers of these materials. 2 or both may be formed.

[0138] The light emitted from the light-emitting layer 130 is emitted from one or both of the electrodes 101 and 102. Therefore, at least one of the electrodes 101 and 102 is visible. The conductive material has a function of transmitting light. The transmittance is 40% or more and 100% or less, preferably 60% or more and 100% or less, and the resistance Resistance is 1×10 -2 Materials with a conductivity of Ω cm or less are also suitable. The electrode is made of a conductive material having a function of transmitting light and a function of reflecting light. The conductive material has a visible light reflectance of 20% or more and 80% or less, preferably 4 0% to 70% and its resistivity is 1×10 -2 Conductive materials with a resistance of Ω·cm or less When a material with low optical transparency, such as a metal or alloy, is used for the electrode that extracts light, The electrode 10 is formed with a thickness that is thick enough to transmit visible light (for example, 1 nm to 10 nm). Either or both of the electrode 101 and the electrode 102 may be formed.

[0139] In this specification and the like, the electrode having a function of transmitting light includes an electrode having a function of transmitting visible light. Any material having both the function and electrical conductivity may be used, and examples thereof include ITO as mentioned above. In addition to the oxide conductor layer, an oxide semiconductor layer or an organic conductor layer containing an organic material is included. The organic conductive layer containing an organic substance may be, for example, a layer containing an organic compound and an electron donor. A layer including a composite material obtained by mixing an organic compound and an electron acceptor. The resistivity of the transparent conductive layer is preferably 1×10 5 Ω cm or less, more preferably 1×10 4 Ω·cm or less.

[0140] The electrode 101 and the electrode 102 may be formed by a sputtering method, a vapor deposition method, a printing method, or the like. Coating method, MBE (Molecular Beam Epitaxy) method, CVD method, Pulse Laser deposition method, ALD (Atomic Layer Deposition) method, etc. It can be used as appropriate.

[0141] <Hole injection layer> The hole injection layer 111 is configured to inject holes from one of the pair of electrodes (electrode 101 or electrode 102). It has the function of promoting hole injection by reducing the injection barrier. It is formed by phthalocyanine derivatives or aromatic amines. Transition metal oxides and Examples include molybdenum oxide, vanadium oxide, ruthenium oxide, and tungsten oxide. , manganese oxide, etc. Phthalocyanine derivatives include phthalocyanine, Examples of aromatic amines include benzidine derivatives and phenyl Diamine derivatives, etc. Polymer compounds such as polythiophene and polyaniline It is also possible to use self-doped polythiophenes, such as poly(ethylenediamine). Representative examples include poly(oxythiophene) / poly(styrenesulfonic acid).

[0142] The hole injection layer 111 is made of a compound of a hole transporting material and a material that has an electron accepting property. Alternatively, a layer containing a material exhibiting electron accepting properties and a layer containing a positive electrode may be used. A stack of layers containing hole transporting materials may also be used. It is possible to give and receive electric charges in the presence of a magnetic field. Materials that exhibit electron-accepting properties include quinodimethane. Organic acceptors such as aryl, chloranil, and hexaazatriphenylene derivatives Specifically, 7,7,8,8-tetracyano-2,3,5,6- Tetrafluoroquinodimethane (abbreviation: F4-TCNQ), chloranil, 2,3,6,7, 10,11-Hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation These are compounds that have electron-withdrawing groups (halogen groups or cyano groups) such as aryloxycarbonyl (HAT-CN). In addition, transition metal oxides, for example oxides of metals in Groups 4 to 8, can be used. In particular, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, and oxide These include tungsten oxide, manganese oxide, and rhenium oxide. Among these, molybdenum oxide is Among these, it is preferred because it is stable, has low hygroscopicity, and is easy to handle.

[0143] As the hole transporting material, a material having a higher hole transporting property than an electron transporting property can be used. ×10 -6 cm 2 It is preferable that the material has a hole mobility of 1 / Vs or more. The aromatic amines and the like listed as hole transporting materials that can be used in the light emitting layer 130 are Carbazole derivatives can be used. Aromatic hydrocarbons and stilbene derivatives can also be used. The hole transporting material may be a polymer compound.

[0144] Examples of aromatic hydrocarbons include 2-tert-butyl-9,10-di(2-naphthyl) 2-tert-butyl-9,10-di(1 -naphthyl)anthracene, 9,10-bis(3,5-diphenylphenyl)anthracene DPPA, 2-tert-butyl-9,10-bis(4-phenylphenyl) )anthracene (abbreviation: t-BuDBA), 9,10-di(2-naphthyl)anthracene (Abbreviation: DNA), 9,10-diphenylanthracene (Abbreviation: DPAnth), 2-t ert-Butylanthracene (abbreviation: t-BuAnth), 9,10-bis(4-methyl -1-naphthyl)anthracene (abbreviation: DMNA), 2-tert-butyl-9,10- Bis[2-(1-naphthyl)phenyl]anthracene, 9,10-bis[2-(1-naphthyl)phenyl]anthracene 2,3,6,7-tetramethyl-9,10-di(1-nathyl)phenyl]anthracene 2,3,6,7-tetramethyl-9,10-di(2-naphthyl)anthracene Anthracene, 9,9'-bianthryl, 10,10'-diphenyl-9,9'-bianthryl tolyl, 10,10'-bis(2-phenylphenyl)-9,9'-bianthryl, 10 ,10'-Bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9'-bis Anthracene, anthracene, tetracene, rubrene, perylene, 2,5,8,11-tetra (tert-butyl)perylene, etc. In addition, pentacene, coronene, etc. can also be used. Thus, 1×10 -6 cm 2 / Vs or more It is more preferable to use aromatic hydrocarbons having 14 or more carbon atoms and 42 or less carbon atoms.

[0145] 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.

[0146] In addition, poly(N-vinylcarbazole) (abbreviation: PVK) and poly(4-vinyltriphenylphosphine) 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 Poly(phenyl)benzidine (abbreviation: Poly-TPD) can also be used. can.

[0147] <Hole transport layer> The hole transport layer 112 is a layer containing a hole transporting material. The hole transport layer 112 is formed by injecting the hole into the hole injection layer 111. Since it has a function of transporting holes to the light-emitting layer 130, it has a HOMO level similar to that of the hole injection layer 111. It is preferable that the HOMO level of each of the aryl groups is the same as or close to the HOMO level of each of the aryl groups.

[0148] As the hole transport material, the material exemplified as the material of the hole injection layer 111 is used. Also, 1×10 -6 cm 2 The material has a hole mobility of ≥ 100 / Vs. However, other materials may be used as long as they have a higher hole transporting property than an electron transporting property. The layer containing a substance having a high hole transporting property may be a single layer or a layer containing the above-mentioned substance. Two or more layers may be laminated.

[0149] ≪Electron transport layer≫ The electron transport layer 118 is connected to the other of the pair of electrodes (electrode 101 or The material has a function of transporting electrons injected from the electrode 102 to the light-emitting layer 130. A material with a higher electron transport capacity than holes can be used as the -6 cm 2 It is preferable that the material has an electron mobility of 100 / Vs or more. As materials with electron transport properties, π-electron-deficient compounds such as nitrogen-containing heteroaromatic compounds are Heteroaromatic compounds and metal complexes can be used. The quinoline ligand, benzoquinoline ligand, and the like, which are listed as examples of electron transporting materials that can be used, Metal complexes having an oxazole ligand or a thiazole ligand are also included. Oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, pyridine derivatives Examples of the derivatives include pyrimidine derivatives, bipyridine derivatives, and pyrimidine derivatives. -6 cm 2 It is preferable that the material has an electron mobility of 1 / Vs or more. Any substance other than the above may be used for the electron transport layer as long as it has a high transportability. The electron transport layer 118 may be a single layer or a stack of two or more layers made of the above substances.

[0150] In addition, a layer for controlling the movement of electron carriers is provided between the electron transport layer 118 and the light emitting layer 130. This is a material having a high electron transporting property and a material having a high electron trapping property. A layer in which a small amount of Zn is added, which suppresses the movement of electron carriers, thereby reducing carrier dispersion. This structure prevents electrons from penetrating the light-emitting layer. This is highly effective in suppressing problems caused by the above-mentioned problems (such as a decrease in element life).

[0151] ≪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 above-mentioned electron transporting material and the corresponding electron A composite material of a material exhibiting electron donating properties can also be used. Examples of the metal include Group 1 metals, Group 2 metals, and oxides thereof. 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 fluorine (ErF3) can be used. An electride may be used for 119. The electride may be, for example, calcium. Examples include a material in which electrons are highly concentrated in a mixed oxide of aluminum and ruthenium. The injection layer 119 may be made of a material that can be used in the electron transport layer 118 .

[0152] In addition, the electron injection layer 119 is made of a composite material obtained by mixing an organic compound and an electron donor. Such composite materials may be made by adding electrons to an organic compound via an electron donor. In this case, the organic compound is It is preferable that the material has excellent transport properties for the generated electrons. Specifically, for example, the above-mentioned The material constituting the electron transport layer 118 (metal complex, heteroaromatic compound, etc.) can be used. The electron donor may be any substance that exhibits electron donating properties to organic compounds. For the metal, alkali metals, alkaline earth metals and rare earth metals are preferred, and lithium, cesium, Magnesium, calcium, erbium, ytterbium, etc. Preferred are lithium metal oxides and alkaline earth metal oxides, and lithium oxide and calcium oxide are preferred. , barium oxide, etc. Also, Lewis bases such as magnesium oxide are used. It is also possible to use organic compounds such as tetrathiafulvalene (TTF). It is also possible.

[0153] The above-mentioned light-emitting layer, hole injection layer, hole transport layer, electron transport layer, and electron injection layer are These are deposition method (including vacuum deposition method), inkjet method, coating method, and nozzle printing method, respectively. The light-emitting layer and the hole-injection layer can be formed by a method such as gravure printing. In addition to the above-mentioned materials, the hole transport layer, the electron transport layer, and the electron injection layer may be made of quantum dots or the like. Inorganic compounds or polymeric compounds (oligomers, dendrimers, polymers, etc.) may be used. stomach.

[0154] The quantum dots are classified into colloidal quantum dots, alloy quantum dots, and core-shell quantum dots. In addition, a group 2 and a group 16, a group 13 and a group 14, and a core type quantum dot may be used. Contains element groups 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 (Ga), Quantum dots containing elements such as Ga, Arsenic, and Aluminum are used. It's fine.

[0155] Examples of liquid media used in wet processes include methyl ethyl ketone, cyclohexane, etc. Ketones such as xanone, fatty acid esters such as ethyl acetate, halogens such as dichlorobenzene Hydrocarbons, aromatics such as toluene, xylene, mesitylene, and cyclohexylbenzene Hydrocarbons, aliphatic hydrocarbons such as cyclohexane, decalin, and dodecane, dimethylformamide, etc. Organic solvents such as dichloromethane (DMF) and dimethyl sulfoxide (DMSO) can be used. Cut.

[0156] Examples of polymer compounds that can be used in the light-emitting layer include poly[2-methoxy]phenylene. [MeH] -PPV), polyphenylenes such as poly(2,5-dioctyl-1,4-phenylenevinylene), Poly(9,9-di-n-octylfluorenyl-2,7 -diyl) (abbreviation: PF8), poly[(9,9-di-n-octylfluorenyl-2,7 -diyl)-alt-(benzo[2,1,3]thiadiazole-4,8-diyl)](abbreviation Name: F8BT), poly[(9,9-di-n-octylfluorenyl-2,7-diyl)- alt-(2,2'-bithiophene-5,5'-diyl)] (abbreviated as F8T2), poly[( 9,9-Dioctyl-2,7-Divinylenefluorenylene)-alt-(9,10-An thracene)], poly[(9,9-dihexylfluorene-2,7-diyl)-alt-( Polyfluorene derivatives such as poly(3-hexyl) Polyalkylthiophenes (P) such as silthiophene-2,5-diyl (abbreviation: P3HT) AT) derivatives, polyphenylene derivatives, etc. Poly(9-vinylcarbazole) (abbreviation: PVK), Poly(2-vinylnaphthalene), Ri[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (abbreviation: PTA A) or the like polymer compound may be doped with a light-emitting compound and used in the light-emitting layer. As the compound, the above-mentioned luminescent compounds can be used.

[0157] <Substrate> In addition, the light-emitting element according to one embodiment of the present invention is provided on a substrate made of glass, plastic, or the like. Regarding the order of fabrication on the substrate, the layers may be stacked in order from the electrode 101 side. They may be laminated in order from the pole 102 side.

[0158] 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. A flexible substrate may be used. The substrate is a flexible substrate, such as polycarbonate. Examples of the substrate include plastic substrates made of polyacrylate and polyarylate. In addition, a film made by vapor deposition may be used in the manufacturing process of the light-emitting element and the optical element. Any other material may be used as long as it functions as a support in the light-emitting device. Anything that has the function of protecting the element and the optical element may be used.

[0159] For example, in the present invention, a light emitting element can be formed using various substrates. The type of the 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, substrate with tungsten foil, flexible substrate, laminated film, fibrous These include cellulose nanofibers (CNF), paper, and base films that contain the above materials. Examples of glass substrates include barium borosilicate glass, aluminoborosilicate glass, or Soda lime glass, etc. Flexible substrates, laminated films, base films, etc. Examples include polyethylene terephthalate (PET), poly Polyethylene naphthalate (PEN), polyethersulfone (PES), polytetrafluoroethylene Examples of plastics include PTFE (polytetrafluoroethylene). Resins such as acrylic resins are also available. Examples include polypropylene, polyester, and polypropylene. Examples include polyvinyl fluoride, polyvinyl chloride, etc., or polyamide, Examples include polyimide, aramid, epoxy, inorganic vapor deposition film, and paper.

[0160] In addition, 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 chip is completed, it is separated from the board and used to transfer it to another board. In this case, the light-emitting element can be transferred onto a substrate having poor heat resistance or a flexible substrate. The above-mentioned peeling layer has a laminated structure of inorganic films, for example, a tungsten film and a silicon oxide film. or a structure in which a resin film such as polyimide is formed on a substrate.

[0161] 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 above mentioned substrates, cellophane substrates, stone substrates, wood substrates, fabric substrates (natural fibers (silk, cotton, Hemp), synthetic fibers (nylon, polyurethane, polyester) or regenerated fibers (acetate (including cellulose, cupra, rayon, recycled polyester, etc.), leather substrate, rubber substrate, etc. By using these substrates, light-emitting elements that are not easily broken and have high heat resistance can be produced. The light emitting element may be a small light emitting element, a light emitting element that is lighter in weight, or a light emitting element that is thinner.

[0162] Also, for example, a field effect transistor (FET) is formed on the above-mentioned substrate, and the FET and The light emitting element 150 may be fabricated on the electrically connected electrodes. In this way, an active matrix display device that controls the driving of light emitting elements can be manufactured.

[0163] The structure shown in this embodiment mode can be used in appropriate combination with other embodiment modes. Cut.

[0164] (Embodiment 2) In this embodiment mode, a light-emitting element having a different structure from that shown in Embodiment 1 and The light emitting mechanism of the light emitting element will be described below with reference to FIG. The parts having the same functions as those shown in 1 are shown with the same hatch pattern and the reference numbers are omitted. In addition, parts having similar functions are denoted by similar reference numerals, and their detailed explanations will be omitted. may be omitted.

[0165] <Example of the configuration of light-emitting element> FIG. 5 is a schematic cross-sectional view of the light-emitting element 250. As shown in FIG.

[0166] The light-emitting element 250 shown in FIG. 5 has a plurality of electrodes between a pair of electrodes (electrodes 101 and 102). In FIG. 5, the light-emitting unit 106 and the light-emitting unit 108 are included. One light-emitting unit has a structure similar to that of the EL layer 100 shown in FIG. The light-emitting element 150 shown as 1 has one light-emitting unit, and the light-emitting element 250 has multiple light-emitting elements. In the light-emitting element 250, the electrode 101 functions as an anode, The following description will be given assuming that the electrode 102 functions as a cathode. The reverse is also acceptable.

[0167] In addition, in the light-emitting element 250 shown in FIG. The light-emitting unit 106 and the light-emitting unit 108 are laminated together, and a charge generating layer 1 is provided between the light-emitting unit 106 and the light-emitting unit 108. The light-emitting units 106 and 108 have different configurations. For example, the light-emitting unit 106 may have a structure similar to that of the EL layer 100 shown in FIG. It is preferable to use a composition.

[0168] The light emitting element 250 includes a light emitting layer 130 and a light emitting layer 170. In addition to the light-emitting layer 130, the knit 106 includes a hole injection layer 111, a hole transport layer 112, an electron transport 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 Has 9.

[0169] The charge generating layer 115 is formed by adding an acceptor material, which is an electron acceptor, to a hole transporting material. Even if the structure is such that the electron transport material is a material having a donor property, the structure may be such that the donor property is added to the electron transport material. In addition, both of these configurations may be laminated.

[0170] When the charge generating layer 115 contains a composite material of an organic compound and an acceptor substance, As the composite material, the composite material which can be used for the hole-injection layer 111 shown in Embodiment 1 is used. The organic compounds include aromatic amine compounds, carbazole compounds, aromatic carbon compounds, etc. Various compounds such as hydrogen and polymer compounds (oligomers, dendrimers, polymers, etc.) are used. As an organic compound, a hole mobility of 1×10 -6 cm 2 / Vs However, it is preferable to use a substance having a higher hole transporting property than an electron transporting property. Other materials may be used as long as they are compatible with the organic compound and the acceptor material. The material has excellent carrier injection and transport properties, enabling low-voltage and low-current operation. In addition, as in the case of the light-emitting unit 108, the surface of the light-emitting unit on the anode side is When the charge generating layer 115 is in contact with the charge generating layer 115, the charge generating layer 115 is in contact with the hole injection layer of the light emitting unit. The light-emitting unit can also function as a hole-injection layer or a hole-transport layer. The hole transport layer may not be provided.

[0171] The charge generating layer 115 may be a layer including a composite material of an organic compound and an acceptor substance. For example, the organic EL element may be formed as a laminated structure in which layers made of the organic EL element are combined. A layer including a composite material of a compound and an acceptor material, and a layer including a compound selected from an electron donor material. The compound may be combined with a compound having a high electron transporting property to form a layer. A layer containing a composite material of an organic compound and an acceptor substance and a layer containing a transparent conductive material are combined. It may also be formed by combining.

[0172] The charge generating layer 115 sandwiched between the light emitting unit 106 and the light emitting unit 108 is 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 the electrode 1 injects holes into the other light-emitting unit. When a voltage is applied so that the potential of electrode 01 is higher than the potential of electrode 102, a charge is generated. Layer 115 injects electrons into light-emitting unit 106 and holes into light-emitting unit 108. .

[0173] From the viewpoint of light extraction efficiency, the charge generating layer 115 is required to be transparent to visible light (specifically, It is preferable that the charge generating layer 115 has a visible light transmittance of 40% or more. In addition, the charge generating layer 115 has a lower electrical conductivity than the pair of electrodes (the electrodes 101 and 102). If the conductivity of the charge generating layer 115 is as high as that of the pair of electrodes, the charge Carriers generated by the generation layer 115 flow in the direction of the film surface, and the electrode 101 and the electrode In some cases, light emission occurs in areas where the light emitting element 102 does not overlap. To achieve this, the charge generating layer 115 is preferably formed of a material having a lower electrical conductivity than the pair of electrodes. It is nice.

[0174] When the charge generating layer 115 is formed using the above-mentioned material, the light emitting layer is laminated. In this case, the increase in the driving voltage can be suppressed.

[0175] In addition, in FIG. 5, a light emitting element having two light emitting units has been described. The same can be applied to a light-emitting element in which two or more light-emitting units are stacked. As shown in the light-emitting element 250, a plurality of light-emitting units are separated by a charge generating layer between a pair of electrodes. By arranging the LEDs in this way, it is possible to achieve high brightness light emission while keeping the current density low, and also to achieve a long life. In addition, a light-emitting element with low power consumption can be realized.

[0176] At least one of the multiple units includes the EL layer 100 shown in FIG. By applying the above structure, a light-emitting element with high luminous efficiency can be provided.

[0177] The light-emitting layer 130 of the light-emitting unit 106 has the structure shown in the first embodiment. In this way, the light emitting element 250 becomes a light emitting element with high light emitting efficiency, which is preferable. It is.

[0178] The guest materials used in the light-emitting units 106 and 108 are the same as those used in the light-emitting units 106 and 108. The light-emitting units 106 and 108 may have the same gate. When the light emitting element 250 has a resist material, the light emitting element 250 exhibits high light emission luminance with a small current value. In addition, the light-emitting unit 106 and the light-emitting unit 108 may have different guest materials. In this case, the light emitting device 250 becomes a light emitting device that exhibits multicolor emission, which is preferable. The gate is designed to emit white light with high brightness, or at least light having red, green and blue colors. It is preferable to select a stainless material.

[0179] The light-emitting unit 106, the light-emitting unit 108, and the charge generating layer 115 are formed by deposition ( (including vacuum deposition), inkjet printing, coating, gravure printing, etc. can be done.

[0180] Note that the structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. There can be.

[0181] (Embodiment 3) In this embodiment mode, a light-emitting element having a different structure from those shown in Embodiments 1 and 2 is described. An example of this will be described below with reference to FIGS.

[0182] <Configuration example 1 of light-emitting element> FIG. 6 is a cross-sectional view illustrating a light-emitting element according to one embodiment of the present invention. The same hatch pattern is used for parts having the same function as the reference numerals shown, and the reference numerals may be omitted. In addition, parts having similar functions are denoted by similar reference numerals, and detailed explanations thereof will be omitted. It may be omitted.

[0183] The light emitting device 260 shown in FIG. 6 is a bottom-emitting device that extracts light toward the substrate 200 side. The light emitting device may be a top emission type (top emission) type that extracts light in the direction opposite to the substrate 200. Note that one embodiment of the present invention is not limited thereto. The light emitted by the light emitting element is emitted from both the upper and lower sides of the substrate 200. The light emitting element may be a dual emission type light emitting element.

[0184] When the light emitting element 260 is a bottom emission type, the electrode 101 has a function of transmitting light. It is preferable that the electrode 102 has a function of reflecting light. Alternatively, when the light emitting element 260 is a top emission type, the electrode 101 is It is preferable that the electrode 102 has a function of reflecting light. In addition, the electrode 102 has a function of transmitting light. It is preferable to do so.

[0185] The light emitting element 260 has an electrode 101 and an electrode 102 on a substrate 200. Between the electrode 101 and the electrode 102, the light-emitting layer 123B, the light-emitting layer 123G, and the light-emitting layer 123R are provided. , a hole injection layer 111, a hole transport layer 112, an electron transport layer 118, and and a child injection layer 119.

[0186] The electrode 101 may be formed of a plurality of conductive layers. In that case, the function of reflecting light is and a conductive layer having a function of transmitting light are preferably laminated together. .

[0187] The electrode 101 has the same configuration as the electrode 101 or the electrode 102 shown in the first embodiment. and materials can be used.

[0188] In FIG. 6, a region 221B and a region 221G are sandwiched between the electrodes 101 and 102. A partition 145 is provided between the region 221R and the region 221R. The partition 145 has insulating properties. The partition 145 covers the end of the electrode 101 and has an opening that overlaps with the electrode. By this, the electrodes 101 on the substrate 200 in each region can be separated into islands. It becomes possible.

[0189] The light-emitting layer 123B and the light-emitting layer 123G are alternately arranged in the region where they overlap with the partition wall 145. The light-emitting layer 123G and the light-emitting layer 123R may have an overlapping area. In the region where the light-emitting layer 1 overlaps the wall 145, the light-emitting layer 1 may have an overlapping region. The light-emitting layer 23R and the light-emitting layer 123B overlap each other in the region where they overlap with the partition wall 145. It may have.

[0190] 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, etc. Examples of the organic material include silicon, aluminum oxide, and aluminum nitride. For example, photosensitive resin materials such as acrylic resin and polyimide resin can be used.

[0191] In addition, the light-emitting layers 123R, 123G, and 123B each exhibit a different color. For example, the light-emitting layer 123R may have a red light-emitting material. By including a light-emitting material having a function of emitting red light, the region 221R emits red light, and the light-emitting layer 12 Since the region 3G 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 having a function of emitting blue light, so that the region 221 The light emitting element 260 having such a configuration is used as a pixel of a display device. By using these, a display device capable of full color display can be manufactured. The thicknesses of the light-emitting layers may be the same or different.

[0192] In addition, any one or more of the light-emitting layers 123B, 123G, and 123R are The light-emitting layer 130 preferably has the configuration of the light-emitting layer 130 shown in the first embodiment. In this way, a light-emitting element with high luminous efficiency can be manufactured.

[0193] In addition, any one or more of the light-emitting layers 123B, 123G, and 123R The light emitting layer may have a structure in which two or more layers are laminated.

[0194] As described above, at least one light-emitting layer has the light-emitting layer shown in embodiment 1, By using the light emitting element 260 having the layer as a pixel of a display device, a display device with high light emitting efficiency can be obtained. That is, a display device having the light-emitting element 260 can be manufactured with low power consumption. It can be reduced.

[0195] In addition, by providing a color filter on the electrode for extracting light, the color purity of the light emitting element 260 can be improved. Therefore, the color purity of the display device having the light emitting element 260 can be improved. It can be done.

[0196] In addition, by providing a polarizing plate on the electrode for extracting light, the reflection of external light from the light emitting element 260 is reduced. Therefore, the contrast ratio of a display device having the light emitting device 260 can be improved. It can be done.

[0197] Other configurations of the light emitting device 260 are the same as those of the light emitting device in the first embodiment. Please take the configuration into consideration.

[0198] <Light-emitting element configuration example 2> Next, a configuration example different from that of the light-emitting element shown in FIG. 6 will be described below with reference to FIGS. 7(A) and 7(B). Provide an explanation.

[0199] 7(A) and (B) are cross-sectional views showing a light-emitting element according to one embodiment of the present invention. In (B), the same hatch patterns are used for the parts having the same functions as those shown in FIG. In addition, parts having similar functions are designated with similar symbols. In some cases, detailed explanations thereof will be omitted.

[0200] 7A and 7B show examples of the configuration of a light-emitting element having a light-emitting layer between a pair of electrodes. The light emitting element 262a shown in (A) is 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. 7B is a top emission type light emitting element. However, the present invention is directed to a bottom emission type light emitting device. One embodiment is not limited to this, and light emitted by the light emitting element may be emitted on the substrate 200 on which the light emitting element is formed. It may also be of a dual emission type in which light is emitted from both the top and bottom.

[0201] 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. , an electrode 103, and an electrode 104. In addition, between the electrode 101 and the 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. The charge generating layer 115 is a hole injection layer 111 and a hole transport layer 11. 2, a light-emitting layer 170, 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 .

[0202] 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 that is 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 a conductive layer 104b.

[0203] The light emitting element 262a shown in FIG. 7(A) and the light emitting element 262b shown in FIG. 7(B) have an electrode The region 222B sandwiched between the electrodes 101 and 102, and the region 222B sandwiched between the electrodes 102 and 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 03 and the end of the electrode 104, and has an opening overlapping the electrode. By this, it is possible to separate the electrodes on the substrate 200 in each region into islands. It becomes.

[0204] The light emitting element 262a and the light emitting element 262b are disposed in the regions 222B, 222G, and In the direction in which the light emitted from the region 222R is extracted, the optical element 224B and the optical element 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 from the region 222R through the optical element 224G is It is ejected.

[0205] In addition, the optical elements 224B, 224G, and 224R are 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.

[0206] The optical element 224R, the optical element 224G, and the optical element 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 converts incident light into the corresponding color. The color conversion element is an optical element that converts the wavelength of the 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.

[0207] In addition, a plurality of optical elements are provided on the optical element 224R, the optical element 224G, and the optical element 224B. Other optical elements, such as a circular polarizer and an anti-reflection film, may be provided. The circular polarizing plate can be provided on the side from which the light emitted by the light emitting element of the display device is extracted. When the display device is turned on, the light incident from outside the display device is reflected inside the display device and emitted to the outside. In addition, the provision of an anti-reflection film can prevent the reflection on the surface of the display device. External light can be weakened, allowing the light emitted by the display device to be clearly observed.

[0208] In FIG. 7(A) and (B), the light emitted from each region through each optical element is Light exhibiting color (B), light exhibiting green (G), and light exhibiting red (R), respectively. This is illustrated diagrammatically by dashed arrows.

[0209] 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 is to be noted that the light shielding layer 223 may not be provided. stomach.

[0210] 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.

[0211] For the substrate 200 and the substrate 220 having the optical element, refer to the first embodiment. That's good.

[0212] Furthermore, the light emitting element 262a and the light emitting element 262b have a microcavity structure. .

[0213] <Microcavity structure> The light emitted from the light-emitting layer 130 and the light-emitting layer 170 is guided by a pair of electrodes (for example, the electrode 10 The light emitting layer 130 and the light emitting layer 170 are resonated between the electrode 102 and the light emitting layer 130. For example, the reflection area of ​​the electrode 101 is formed at a position where the light of the 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 130 is By adjusting the optical distance to the light emitting region, the amount of light emitted from the light emitting layer 130 can be reduced. In addition, the light emitted from the reflective area of ​​the electrode 101 to the light emitting layer 170 can be intensified. and the optical distance from the reflective area of ​​the electrode 102 to the luminous area of ​​the luminous layer 170. By adjusting the optical path, the light emitted from the light emitting layer 170 can be adjusted to a desired wavelength. That is, the light can be intensified by using a plurality of light-emitting layers (here, the light-emitting layer 130 and the light-emitting layer In the case of a light emitting device in which the light emitting layer 130 and the light emitting layer 170 are laminated, the optical distances of the light emitting layer 130 and the light emitting layer 170 are It is preferable to optimize the spacing.

[0214] 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 thicknesses of the conductive layers 101b, 103b, and 104b, the light-emitting layer 130 In addition, the light emitted from the light emitting layer 170 can be enhanced at a desired wavelength. At least one of the thicknesses of the hole injection layer 111 and the hole transport layer 112 is made different in the region. This may enhance the light emitted from light-emitting layer 130 and light-emitting layer 170.

[0215] For example, the electrodes 101 to 104 are made of a conductive material having a function of reflecting light. In the case where the refractive index is smaller than that of the light-emitting layer 130 or the light-emitting layer 170, the electrode The thickness of the conductive layer 101b of the electrode 101 is set to a value that satisfies the optical distance between the electrode 101 and the electrode 102. 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 or smaller than 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 to m R λ R / 2(m R is natural number, λ R and represent the wavelengths of light to be intensified in region 222R).

[0216] As described above, a microcavity structure is provided, and the optical distance between a pair of electrodes in each region is adjusted. By arranging the electrodes, light scattering and absorption near each electrode are suppressed, resulting in high light extraction efficiency. In the above structure, the conductive layer 101b and the conductive layer 103 It is preferable that the conductive layer 104b has a function of transmitting light. The materials constituting the conductive layers 103b, 104b may be the same as each other. In addition, the conductive layer 101b, the conductive layer 103b, and the conductive layer 104b may be different from each other. Each of these may have a structure in which two or more layers are laminated.

[0217] In addition, the light emitting element 262a shown in FIG. 7A is a top emission type light emitting element, so that the conductive The layer 101a, the conductive layer 103a, and the conductive layer 104a may have a function of reflecting light. In addition, the electrode 102 has a function of transmitting light and a function of reflecting light. is preferred.

[0218] In addition, the light emitting element 262b shown in FIG. 7B is a bottom emission type light emitting element. The layer 101a, the conductive layer 103a, and the conductive layer 104a have a function of transmitting light and a function of reflecting light. In addition, the electrode 102 preferably has a function of reflecting light. preferable.

[0219] In the light-emitting element 262a and the light-emitting element 262b, the conductive layer 101a and the conductive layer 10 3a and conductive layer 104a may be made of the same material or different materials. When the conductive layer 101a, the conductive layer 103a, and the conductive layer 104a are made of the same material, The manufacturing cost of the conductive layer 101a and the light emitting element 262b can be reduced. Each of the conductive layer 103a and the conductive layer 104a may be configured by stacking two or more layers. stomach.

[0220] The light-emitting layer 130 in the light-emitting element 262a and the light-emitting element 262b is the same as that in the first embodiment. By doing so, a light-emitting element having high luminous efficiency can be obtained. It can be made.

[0221] The light-emitting layer 130 and the light-emitting layer 170 are, for example, the light-emitting layer 170a and the light-emitting layer 170b. In this way, one or both of the light-emitting layers may have a structure in which two layers are laminated. Two types of luminescent materials, a luminescent material and a second luminescent material, which have the function of exhibiting different colors, are used. By using each of them, it is possible to obtain light emission including a plurality of colors. The luminescent material used for each luminescent layer is selected so that the luminescent layer 170 emits white light. It is preferable to select

[0222] In addition, the light-emitting layer 130 or the light-emitting layer 170 may have a structure in which three or more layers are laminated on one or both sides. The light-emitting layer may be made of any material, and may include a layer that does not have a light-emitting material.

[0223] As described above, the light-emitting element 262a having the light-emitting layer structure shown in Embodiment 1 or the light-emitting element By using the optical element 262b as a pixel of a display device, a display device with high light emission efficiency is manufactured. That is, a display device having the light emitting element 262a or the light emitting element 262b can , power consumption can be reduced.

[0224] Regarding other configurations of the light emitting element 262a and the light emitting element 262b, 260, or the structures of the light-emitting elements shown in Embodiments 1 and 2 may be taken into consideration. stomach.

[0225] Note that the structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. There can be.

[0226] (Embodiment 4) 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. This will be explained using 10.

[0227] <Display device configuration example 1> FIG. 8A is a top view showing the display device 600, and FIG. 8B is a diagram showing the display device 600 along the dashed line AB in FIG. The display device 600 includes a driving 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.

[0228] The display device 600 includes an element substrate 610, a sealing substrate 604, a sealant 605, The semiconductor device has an area 607 surrounded by a sealing material 605, wiring 608, and an FPC 609. do.

[0229] 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. It is connected to the external input terminal FPC609 and It receives the FP signal, clock signal, start signal, reset signal, etc. Although only C609 is shown, FPC609 has a printed wiring board (PWB: Pri A standard Wiring Board may be installed.

[0230] The signal line driver circuit portion 601 includes an N-channel transistor 623 and a P-channel A CMOS circuit is formed by combining this transistor 624. The path section 601 or the scanning line driver circuit section 603 may be implemented by various CMOS circuits, PMOS circuits, or In this embodiment, the driving circuit section is formed on the substrate. Although the display device shown has the driver and pixels formed on the same surface, this is not necessarily the case. Alternatively, the driving circuitry may be formed externally rather than on the substrate.

[0231] The pixel portion 602 includes a switching transistor 611 and a current control transistor 612. A lower part electrically connected to the drain of the transistor 612 for current control A partition wall 614 is formed to cover an end of the lower electrode 613. The partition wall 614 can be made of a positive photosensitive acrylic resin film.

[0232] 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, a positive photosensitive acrylic is used as the material for the partition wall 614. In this case, only the upper end of the partition wall 614 is curved with 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 above-mentioned photosensitive resins can be used.

[0233] 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. The structure is such that the transistors are either N-channel or P-channel. A structure consisting of only one of the two may be used. For example, an amorphous semiconductor film or a crystalline semiconductor film may be used. Semiconductor materials include group 14 (silicon, etc.) semiconductors, compound semiconductors (oxide As the transistor, for example, The energy gap is 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 a 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 neodymium (Nb). Examples include Nd (Nd).

[0234] 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.

[0235] The EL layer 616 is formed by a deposition method (including a vacuum deposition method) using a deposition mask, a droplet discharge method, etc. (also called inkjet method), spin coating method, gravure printing method, etc. The EL layer 616 is formed by the method. The material for forming the EL layer 616 is a low molecular weight compound, Alternatively, it may be a polymer compound (including an oligomer or a dendrimer).

[0236] The lower electrode 613, the EL layer 616, and the upper electrode 617 constitute a light-emitting element 618. The light emitting element 618 has the structure of any one of the first to third embodiments. In addition, in the case where a plurality of light-emitting elements are formed in a pixel portion, The light-emitting element according to the third embodiment and the light-emitting element having other structures are both included. That's fine.

[0237] In addition, the sealing substrate 604 is bonded to the element substrate 610 with the sealant 605, A light-emitting element is disposed in an area 607 surrounded by an element substrate 610, a sealing substrate 604, and a sealant 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 sealant 605. They may also be filled with UV-curable or heat-curable resins, e.g. PVC ( Polyvinyl chloride) resin, acrylic resin, polyimide resin, epoxy resin, Silicone resin, PVB (polyvinyl butyral) resin, or EVA (ethylene vinyl acetate) A recess is formed in the sealing substrate, and a desiccant is placed therein. By providing this, deterioration due to the influence of moisture can be suppressed, and this is a preferable configuration.

[0238] 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.

[0239] It is preferable to use epoxy resin or glass frit for the sealing material 605. In addition, it is desirable that these materials are 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 FRP (Fiber Reinforced Plastics). Reinforced Plastics), PVF (Polyvinyl Fluoride), Poly A plastic substrate made of ester, acrylic or the like can be used.

[0240] As described above, the light emitting element and the optical element described in any of the first to third embodiments are provided. It is possible to obtain a display device that

[0241] <Display device configuration example 2> Next, another example of the display device will be described with reference to FIGS. 9(A) and 9(B) are cross-sectional views of a display device according to one embodiment of the present invention.

[0242] FIG. 9A shows a substrate 1001, an insulating base film 1002, a gate insulating film 1003, and a gate electrode 1004. Poles 1006, 1007, 1008, a first interlayer insulating film 1020, a second interlayer insulating film 102 1, peripheral portion 1042, pixel portion 1040, driving circuit portion 1041, lower electrode 102 of light emitting element 4R, 1024G, 1024B, partition wall 1025, EL layer 1028, upper electrode 1 of light-emitting element 026, a sealing layer 1029, a sealing substrate 1031, a sealant 1032, and the like are shown.

[0243] In addition, in FIG. 9A, as an example of an optical element, a colored layer (a red colored layer 1034R, a green colored layer A transparent substrate 1033 is provided with a colored layer 1034G of a different color and a blue colored layer 1034B of a different color. A light-shielding layer 1035 may be further provided. The base material 1033 is aligned and fixed to the substrate 1001. The colored layer and the light-shielding layer are 9A, the colored layer is covered with an overcoat layer 1036. Since the light that passes through is red, green, and blue, images can be displayed using three color pixels.

[0244] In FIG. 9B, as an example of an optical element, a colored layer (a red colored layer 1034R, a green colored layer The blue color layer 1034G and the blue color layer 1034B are disposed 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 sealing substrate 1020. It may be provided between the plates 1031.

[0245] As an example of the optical element, a colored layer (a red colored layer 1034R, a green colored layer 103 4G, a blue colored layer 1034B) is formed between the first interlayer insulating film 1020 and the second interlayer insulating film 102 It may be formed between the

[0246] In the display device described above, the side of the substrate 1001 on which the transistors are formed is The display device has a bottom emission structure for extracting light. The display device may also have a structure for extracting emitted light (top emission type).

[0247] <Display device configuration example 3> An example of a cross-sectional view of a top-emission type display device is shown in FIG. 10(A) and (B). 9(A) and 9(B) are cross-sectional views illustrating a display device of one embodiment of the present invention. 1, the driver circuit section 1041, the peripheral section 1042, and the like are omitted.

[0248] In this case, the substrate 1001 can be a substrate that does not transmit light. A bottom emission type display device is manufactured until the connection electrode for connecting the anode of the optical element is fabricated. Thereafter, a third interlayer insulating film 1037 is formed so as to cover the electrode 1022. This insulating film may also play a role in planarization. The third interlayer insulating film 1037 is the first In addition to the same material as the interlayer insulating film 2, various other materials can be used.

[0249] 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 10(A)(B) are also acceptable. In the case of a photodiode 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.

[0250] In the top emission structure shown in FIG. 10(A), the colored layer (red colored layer 1034 R, a green colored layer 1034G, and a blue colored layer 1034B) are provided on the sealing substrate 1031 The sealing substrate 1031 has a shielding layer between the pixels. An optical layer 1035 may be provided. Note that the sealing substrate 1031 may be a light-transmitting substrate. This is preferable.

[0251] In addition, in FIG. 10A, a plurality of light emitting elements and the plurality of light emitting elements are colored. Although the configuration in which a layer is provided has been illustrated, the present invention is not limited to this. For example, as shown in FIG. In the embodiment, the green color layer is not provided, and a red color layer 1034R and a blue color layer 1034B are provided. It is also possible to use three colors, red, green, and blue, for full color display. In this way, when a light emitting element and a colored layer are provided for each of the light emitting elements, the reflection of external light can be reduced. On the other hand, as shown in FIG. 10B, the light emitting element is provided with a green In the case where a red colored layer and a blue colored layer are provided instead of providing a colored layer of green, Since the energy loss of the light emitted from the light-emitting element is small, power consumption can be reduced. This has a positive effect.

[0252] The display device described above has a configuration having three sub-pixels of three colors (red, green, and blue). A structure with four sub-pixels of four colors (red, green, blue, yellow, or red, green, blue, white) In that case, the function of transmitting yellow light or the function of transmitting blue, green, yellow, and red light may be used. A colored layer having a function of transmitting a plurality of lights selected from the following can be used. When the layer has a function of transmitting a plurality of light beams selected from blue, green, yellow, and red, the The light transmitted through the colored layer may be white. The light emitting element that emits yellow or white light is Since the light emission efficiency is high, a display device having such a structure can reduce power consumption. Cut.

[0253] The display device 600 shown in FIG. 8 includes an element substrate 610, a sealing substrate 604, and a sealing material. A sealing layer may be formed in the area 607 surrounded by 605. The sealing layer may include, for example, PV C (Polyvinyl chloride) resin, acrylic resin, polyimide resin, epoxy resin grease, silicone resin, PVB (polyvinyl butyral) resin, or EVA (ethylene Resins such as vinyl acetate resins can be used. Silicon oxide, oxynitride, etc. Silicon oxide, silicon nitride oxide, silicon nitride, aluminum oxide, aluminum nitride, etc. By forming a sealing layer in the region 607, impurities such as water can be prevented from being generated. This is preferable because it can suppress deterioration of the light emitting element 618. The sealing material 605 does not have to be provided.

[0254] In addition, by forming the sealing layer in multiple layers, impurities such as water can be prevented from entering the display device 600 from the outside. This is preferable because it can effectively prevent the light from reaching the light emitting element 618 inside the device. In addition, when the sealing layer has multiple layers, it is preferable to laminate a resin and an inorganic material.

[0255] Note that the configuration shown in this embodiment may be appropriately combined with other embodiments or other configurations in this embodiment. Combinations are possible.

[0256] (Embodiment 5) In this embodiment, an electronic device, a light-emitting device, and a lighting device each including a light-emitting element of one embodiment of the present invention will be described. The device will be described with reference to FIGS.

[0257] <Electronic device information> 11(A) to 11(G) are diagrams showing electronic devices. These electronic devices are A body 9000, a display unit 9001, a speaker 9003, and operation keys 9005 (power switch, etc.) 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 rays The sensor 9005 may also include a microphone 9008, etc. 007 may have a function of measuring biological information, such as a pulse sensor or a fingerprint sensor.

[0258] The electronic devices illustrated in FIGS. 11A to 11G can have various functions. For example, the function to display various information (still images, videos, text images, etc.) on the display, Sensor function, calendar, date or time display function, various software ( A function to control processing by 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 displaying the program or data. The present invention can have a function of displaying information on a display unit, etc. The functions that the electronic device shown in the figure can have are not limited to these, and the electronic device may have a variety of functions. Although not shown in FIG. 11(A) to FIG. 11(G), the electronic device may include The electronic device may have a plurality of display units. The function to take pictures, record videos, and store the images on a recording medium (external or built-in to the camera) ) and a function for displaying the captured image on a display unit.

[0259] The electronic devices shown in FIGS. 11A to 11G will be described in detail below.

[0260] FIG. 11A is a perspective view showing a portable information terminal 9100. The display unit 9001 has flexibility. The display unit 9001 can be incorporated along the screen. The device is equipped with a touch sensor, and can be operated by touching the screen with a finger or a stylus. By touching the icon displayed on the display 9001, the application can be started. can.

[0261] FIG. 11B is a perspective view showing a portable information terminal 9101. For example, the device has one or more functions selected from a telephone, a notebook, an information viewing device, etc. Specifically, the mobile information terminal 9101 can be used as a smartphone. Although the speaker 9003, the connection terminal 9006, the sensor 9007, etc. are omitted in the figure, The mobile information terminal 9100 shown in FIG. 11(A) can be installed in the same position. The information terminal 9101 can display text and image information on multiple surfaces. For example, Three operation buttons 9050 (also called operation icons or simply icons) are displayed on the display unit 900. The information 9051 shown in the dashed rectangle can be displayed on one side of the display unit 90. 01. An example of the information 9051 is an e-mail Displays to notify you of incoming calls, SNS (social networking services), etc. , subject of email or SNS, sender name of email or SNS, date and time, time, There are displays showing the remaining battery level, the strength of the received signal, etc. Even if the operation button 9050 is displayed instead of the information 9051 at the displayed position, good.

[0262] The housing 9000 is made of a material such as alloy, plastic, or ceramic. The plastic may be reinforced plastic. Carbon Fiber Reinforced Plastic Composite (CFRP), a type of plastic Carbon fiber reinforced plastics (CFRP) has the advantage of being lightweight and non-corrosive. Other reinforced plastics include glass fiber reinforced plastics and aramid fiber reinforced plastics. Examples of alloys include aluminum alloys and Magnesium alloys include non-ferrous metals containing zirconium, copper, nickel and titanium. Amorphous alloys (also called metallic glasses) have superior elastic strength. It is an amorphous alloy that has a glass transition region at room temperature and is also called a bulk-solidifying amorphous alloy. The alloy has a substantially amorphous atomic structure. The alloy material is poured into the housing mold and solidified to form a part of the housing with the bulk solidified amorphous alloy. Amorphous alloys include zirconium, copper, nickel, titanium, as well as beryllium, silicon, and Cobalt, niobium, boron, gallium, molybdenum, tungsten, manganese, iron, cobalt The amorphous alloy may contain yttrium, vanadium, phosphorus, carbon, etc. Not limited to solid casting, vacuum deposition, sputtering, electrolytic plating, electroless plating, etc. In addition, the amorphous alloy does not have a long-range order (periodic structure) as a whole. As long as the alloy maintains a state free of crystallites, it may contain microcrystals or nanocrystals. , both complete solid solution alloys, which have a single solid phase structure, and partial solutions, which have two or more phases. By using an amorphous alloy for the housing 9000, a housing with high elasticity is achieved. Therefore, even if the portable information terminal 9101 is dropped, the housing 9000 is made of an amorphous alloy. If the mobile information terminal 910 is used, it will return to its original shape even if it is temporarily deformed at the moment of impact. 1 can improve the impact resistance.

[0263] FIG. 11C is a perspective view showing a portable information terminal 9102. , and has a function of displaying information on three or more faces of the display unit 9001. An example is shown in which information 9053 and information 9054 are displayed on different sides. The user of the portable information terminal 9102 holds the portable information terminal 9102 in the breast pocket of the clothes. In this state, the display (information 9053 in this case) can be confirmed. The telephone number or name of the caller is displayed on the mobile information terminal 9102 so that it can be observed from above. The user can read the display without taking the mobile information terminal 9102 out of his pocket. You can check the number and decide whether to answer the call or not.

[0264] 11(D) is a perspective view showing a wristwatch-type portable information terminal 9200. The 9200 is used for mobile phone calls, e-mail, document browsing and writing, music playback, and Internet communications. It is possible to execute various applications such as computer games. The display unit 9001 has a curved display surface, and displays information 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, 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. Power may also be supplied wirelessly without going through 6.

[0265] 11(E), (F), and (G) are perspective views showing a foldable portable information terminal 9201. FIG. 11E is a perspective view of the portable information terminal 9201 in an unfolded state. (F) shows the mobile information terminal 9201 being changed from one of the unfolded and folded states to the other. FIG. 11(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 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 9001 is made up of three housings 9000 connected by hinges 9055. The two housings 9000 are supported by the hinge 9055. The portable information terminal 9201 can 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.

[0266] In addition, the electronic device may be, for example, a television device (a television or a television receiver monitors for computers, digital cameras, digital video cameras, etc. Any camera, digital photo frame, or mobile phone (also called a mobile phone or mobile phone device) , goggle-type displays (head-mounted displays), portable game consoles, portable information Examples include terminals, audio playback devices, and large game machines such as pachinko machines.

[0267] Further, the electronic device of one embodiment of the present invention may include a secondary battery and may perform non-contact power transmission. It is preferable that the secondary battery can be charged using the same.

[0268] 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 battery, nickel-cadmium battery, organic radical battery, lead acid battery, secondary air battery, nickel-zinc battery, silver-zinc battery Examples include lead batteries.

[0269] 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.

[0270] In addition, the electronic device or lighting device of one embodiment of the present invention has flexibility and can be used in a house or a building. It can also be installed along the curved surfaces of walls or exterior walls, or the interior or exterior of a car. For example, installing lighting on the dashboard, windshield, ceiling, etc. of a car This can be done.

[0271] <Explanation about the light emitting device> FIG. 12A is a perspective view of a light emitting device 3000 according to this embodiment. A cross-sectional view corresponding to the dashed line EF is shown in FIG. In A), some of the components are shown with dashed lines to avoid cluttering the drawing.

[0272] The light emitting device 3000 shown in FIGS. 12(A) and 12(B) includes a substrate 3001 and a light emitting element on the substrate 3001. A light element 3005, a first sealing region 3007 provided on the outer periphery of the light emitting element 3005, and a second sealing region 3007 provided on the outer periphery of the light emitting element 3005. and a second sealing region 3009 provided on the outer periphery of the first sealing region 3007.

[0273] The light emitted from the light emitting element 3005 is incident on either the substrate 3001 or the substrate 3003. In FIG. 12(A) and (B), the light emitted from the light emitting element 3005 is A configuration in which light is emitted downward (toward the substrate 3001) will be described.

[0274] As shown in FIGS. 12A and 12B, 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 can be effectively suppressed from being contaminated by the ingress of oxygen, for example water, or the like. It is not necessary to provide the first sealing region 3007 and the second sealing region 3009. It may be configured with only 007.

[0275] In FIG. 12B, the first sealing region 3007 and the second sealing region 3009 are 3003. However, the present invention is not limited to this. For example, For example, one or both of the first sealing region 3007 and the second sealing region 3009 may be formed on the substrate 30. Alternatively, the insulating film 01 may be formed above the insulating film 02 in contact with the conductive film. Alternatively, one or both of the first sealing region 3007 and the second sealing region 3009 may be formed on a substrate. It may be configured so as to be in contact with the insulating film or conductive film formed below 3003. stomach.

[0276] 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 a configuration similar to that described in .

[0277] The first sealing region 3007 is made of a material containing glass (for example, glass frit, glass For the second sealing region 3009, a material containing resin may be used. By using a material containing glass for the first sealing region 3007, In addition, the second sealing region 3009 may include 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 3005 is formed of a material containing resin, and the second sealing region 3006 is formed of a material containing glass. Good too.

[0278] The above-mentioned 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. In order to absorb infrared light, It is preferable that both contain one or more transition metals.

[0279] The above-mentioned glass frit can be prepared, for example, by applying a frit paste onto a substrate, This is then subjected to heat treatment or laser irradiation. The binder is a resin diluted with an organic solvent. It is also possible to use a material in which an absorbent that absorbs light of the wavelength of the laser light is added to the laser. As the laser, it is preferable to use, for example, a Nd:YAG laser or a semiconductor laser. In addition, the shape of the laser irradiation may be circular or rectangular.

[0280] Examples of materials containing the above-mentioned resin include polyester, polyolefin, and poly. Amides (nylon, aramid, etc.), polyimides, polycarbonates or acrylic resins, Polyurethane and epoxy resins can be used. Or, siloxane such as silicone can be used. Materials containing resins having SAN bonds can be used.

[0281] In addition, either 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 the plate 3001 from cracking.

[0282] For example, a material containing glass is used for the first sealing region 3007, and a material containing glass is used for the second sealing region 3009. When a material containing resin is used, the following excellent effects are obtained.

[0283] 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, 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 including glass, Even if distortion due to an external force occurs, the light emitting device 3000 is less likely to break.

[0284] As shown in FIG. 12B, 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 3009 and the first sealing region 3012. 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.

[0285] The first region 3011 and the second region 3013 may be, 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 It is preferable that the pressure in the storage tank 10 is reduced below atmospheric pressure.

[0286] A modified example of the configuration shown in FIG. 12(B) is shown in FIG. 12(C). FIG. 3 is a cross-sectional view showing a modified example of the device 3000.

[0287] FIG. 12C shows a substrate 3003 having a recess formed therein, and a desiccant 3018 provided in the recess. The rest of the configuration is the same as that shown in FIG.

[0288] Desiccants 3018 are substances that adsorb moisture by chemical adsorption or substances that adsorb moisture 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 (oxidized calcium and barium oxide), sulfates, metal halides, perchlorates, zeolites, Examples include silica gel.

[0289] <Explanation about lighting equipment> FIG. 13 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 such a curved light-emitting area, a lighting device 8502 can be formed. The light-emitting element shown in this embodiment mode has a thin film shape, and the design of the housing has a high degree of freedom. Therefore, it is possible to form 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.

[0290] 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 makes it possible to provide a lighting device that also functions as furniture.

[0291] As described above, a display module, a light-emitting device, and a display panel using a light-emitting element according to one embodiment of the present invention can be manufactured. The electronic device and the lighting device can be obtained. The applicable lighting device and the electronic device are The present invention is not limited to the embodiment shown in the drawings, but can be applied to lighting devices and electronic devices in various fields. It is possible.

[0292] The structure described in this embodiment may be used in appropriate combination with structures described in other embodiments. There can be. EXAMPLES

[0293] In this example, a manufacturing example of a light-emitting element according to one embodiment of the present invention and characteristics of the light-emitting element will be described. The structure of the light-emitting device fabricated in this example is the same as that shown in FIG. 1. The details of the device structure are shown in Table 1. and Table 2. The structures and abbreviations of the compounds used are shown below.

[0294] [ka]

[0295] [Table 1]

[0296] [Table 2]

[0297] <Fabrication of light-emitting element> A method for manufacturing the light-emitting element manufactured in this embodiment will be described below.

[0298] <Fabrication of light-emitting element 1> An ITSO film was formed on a glass substrate as an electrode 101 to a thickness of 110 nm. The electrode area of ​​the electrode 101 is 4 mm 2 (2mm x 2mm).

[0299] Next, a hole injection layer 111 made of DBT3P-II and molybdenum oxide was formed on the electrode 101. (MoO3) and the weight ratio (DBT3P-II:MoO3) was 1:0.5. The deposition was carried out to a thickness of 60 nm.

[0300] Next, a hole transport layer 112 was formed on the hole injection layer 111 by depositing PCCP to a thickness of 20 nm. The deposition was carried out so that

[0301] Next, on the hole transport layer 112, 4-[3′-(9H-carbazole -9-yl)-1,1'-biphenyl-3-yl]-2,6-diphenylpyrimidine (abbreviation Name: Pm-01) and tris{2-[1-(2,6-diisopropylphenyl)-1H- Imidazol-2-yl-κN 3 ]phenyl-κC}iridium(III) (abbreviation: Ir (iPrpim)3) and the weight ratio (Pm-01:Ir(iPrpim)3) is 1:0. The luminescent layer 130 was co-evaporated to a thickness of 30 nm. In the example, Ir(iPrpim)3 is the guest material (first organic compound) and Pm-01 is the host material. The second organic compound is a photoresist material.

[0302] Next, on the light-emitting layer 130, Pm-01 was deposited to a thickness of 10 nm as the electron transport layer 118. Then, the electron transport layer was evaporated in order to a thickness of 15 nm. On 118, LiF was evaporated as an electron injection layer 119 to a thickness of 1 nm.

[0303] 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.

[0304] Next, in a glove box with a nitrogen atmosphere, a glass substrate for sealing is The EL sealant is used to fix the organic material to the glass substrate, forming a light-emitting element 1. Specifically, a sealant was applied to the periphery of the organic material formed on the glass substrate, and the The glass substrate and the sealing glass substrate are bonded together, and ultraviolet light with a wavelength of 365 nm is applied for 6 hours. J / cm 2 The light-emitting element 1 was obtained by irradiating the light with light and then heat-treating it for 1 hour at 80° C.

[0305] <Fabrication of Light-Emitting Elements 2 to 8> The light-emitting elements 2 to 8 are different from the light-emitting element 1 described above only in the process of forming the light-emitting layer 130. The other steps were the same as those for the light-emitting element 1.

[0306] The light-emitting layer 130 of the light-emitting element 2 is made of PCCP, Pm-01, and Ir(iPrpim). 3, and the weight ratio (PCCP:Pm-01:Ir(iPrpim)3) was 0.33:0.6 They were co-evaporated so that the ratio was 6:0.06 and the thickness was 30 nm.

[0307] The light-emitting layer 130 of the light-emitting element 3 is made of PCCP, Pm-01, and Ir(iPrpim). 3, and the weight ratio (PCCP:Pm-01:Ir(iPrpim)3) was 0.66:0.3 They were co-evaporated so that the ratio was 3:0.06 and the thickness was 30 nm.

[0308] The light-emitting layer 130 of the light-emitting element 4 is made of PCCP and Ir(iPrpim)3 in a weight ratio of (PCCP:Ir(iPrpim)3) is 1:0.06, and the thickness is 30 The light-emitting element 4 was formed by co-evaporation using the second organic compound Pm-01. This is a comparative light-emitting element having a light-emitting layer configuration in which no

[0309] The light-emitting layer 130 of the light-emitting element 5 is made of PCCP, Pm-01, and Ir(iPrpim). 3, and the weight ratio (PCCP:Pm-01:Ir(iPrpim)3) was 0.3:0.6: The layers were co-evaporated to a thickness of 30 nm and a thickness of 0.05.

[0310] The light-emitting layer 130 of the light-emitting element 6 is made of PCCP, Pm-01, and Ir(iPrpim). 3, and the weight ratio (PCCP:Pm-01:Ir(iPrpim)3) was 0.3:0.6: The vapor deposition was carried out so that the molecular weight became 0.1 and the thickness became 30 nm.

[0311] The light-emitting layer 130 of the light-emitting element 7 is made of PCCP, Pm-01, and Ir(iPrpim). 3, and the weight ratio (PCCP:Pm-01:Ir(iPrpim)3) was 0.3:0.6: The vapor deposition was carried out so that the molecular weight became 0.2 and the thickness became 30 nm.

[0312] The light-emitting layer 130 of the light-emitting element 8 is made of PCCP, Pm-01, and Ir(iPrpim). 3, and the weight ratio (PCCP:Pm-01:Ir(iPrpim)3) was 0.3:0.6: The layers were co-evaporated to a thickness of 30 nm and a thickness of 0.3.

[0313] <Characteristics of light-emitting element> Next, the characteristics of the fabricated light-emitting elements 1 to 8 were measured. Measurement of luminance and CIE chromaticity A color luminance meter (Topcon, BM-5A) was used to measure the electroluminescence spectrum. A multichannel spectrometer (PMA-11, manufactured by Hamamatsu Photonics) was used.

[0314] FIG. 14 shows luminance-current density characteristics of the light-emitting elements 1 to 4, and FIG. 15 shows luminance-voltage characteristics of the light-emitting elements 1 to 4. The current efficiency vs. luminance characteristics are shown in FIG. 16, and the power efficiency vs. luminance characteristics are shown in FIG. 17. FIG. 20 shows the luminance-current density characteristics of the light-emitting elements 5 to 8, and FIG. 21 shows the luminance-voltage characteristics of the light-emitting elements 5 to 8. 1, current efficiency-luminance characteristics are shown in FIG. 22, and power efficiency-luminance characteristics are shown in FIG. The measurements of each light-emitting device were carried out at room temperature (an atmosphere maintained at 23° C.).

[0315] Also, 1000cd / m 2 The element characteristics of the light-emitting elements 1 to 8 in the vicinity are shown in Table 3. and shown in Table 4.

[0316] [Table 3]

[0317] [Table 4]

[0318] In addition, the light-emitting elements 1 to 4 and the light-emitting elements 5 to 8 each have a value of 2.5 mA / cm 2 The electroluminescence spectra when a current was applied at a current density of 1000 s are shown in Figs. Each is shown below.

[0319] As shown in FIG. 18 and FIG. 24, the electroluminescence spectrum of the light-emitting element 4 has a peak wavelength of 4 The light-emitting element 1 to the light-emitting element 3 and the light-emitting element 5 mainly emitted blue light at 70 nm. The electroluminescence spectra of the first to eighth samples show blue emission with a peak wavelength of 470 nm, as well as green The light emitted was broad in the wavelength range from red to yellow. The full width at half maximum of the spectra are 119 nm, 106 nm, 75 nm, 54 nm, and 83 nm, respectively. nm, 92 nm, 134 nm, and 153 nm, and the light-emitting elements 1 to 3 and The electroluminescence spectra of the elements 5 to 8 have a broader spectral shape than that of the element 4. On the other hand, the electroluminescence spectrum of the light-emitting element 4 has a narrow spectral shape, and the main We observed light emission from the guest material Ir(iPrpim)3.

[0320] Next, the light-emitting elements 1 to 3 are normalized by the intensity at the peak wavelength of the light-emitting element 4. From the electroluminescence spectra of the light-emitting elements 5 to 8, the electroluminescence spectrum of the light-emitting element 4 The difference spectra from the two spectra are shown in Figs. 19 and 25. The light-emitting elements 1 to 3 and the light-emitting elements 5 to 8 are the same as the light-emitting elements 4 In addition to the emission of the guest material shown in the spectrum, it has broad emission in the yellow wavelength region. It was also found that the peak wavelength of the broad emission was around 540 nm to 550 nm. In addition, the intensity ratio of the emission of the guest material to the broad emission (emission of the guest material: Broad emission) is 1:0.65 for light-emitting element 1, 1:0.45 for light-emitting element 2, 3 is 1:0.20, luminous element 5 is 1:0.22, luminous element 6 is 1:0.29, luminous element 7 For light-emitting element 8, the ratio was 1:0.68, and for light-emitting element 9, the ratio was 1:1.04.

[0321] As will be described later, the light-emitting layers of the light-emitting elements 1 to 3 and the light-emitting elements 5 to 8 The Pm-01 and Ir(iPrpim)3 used in this study are a combination that forms an exciplex. Therefore, the light-emitting elements 1 to 3 and the light-emitting elements 5 to 8 have a wide spectrum. The reason for the spectral shape is that Pm-01 and Ir(iPrpim)3 form an exciplex. This can be attributed to the fact that light emission is obtained from the exciplex.

[0322] Light-emitting element 2 and light-emitting element 3 are made of Pm-01 (a second organic compound) and Ir (iPrpim). The light-emitting device has PCCP (a third organic compound) in addition to the first organic compound. The light-emitting element 1 is a light-emitting element that does not contain PCCP (a third organic compound), and the light-emitting element 4 is a light-emitting element that does not contain PCCP (a third organic compound). is a light-emitting element that does not contain Pm-01 (second organic compound). This is a light-emitting element with a higher proportion of PCCP than light-emitting element 2. In the light-emitting element 4, Pm-01 (the second organic compound) and Ir(iPrpim)3 (the first organic compound) were It was found that the ratio of broad emission originating from the exciplex formed with the organic compound changed. In this way, by changing the ratio of PCCP (the third organic compound) in the light-emitting layer, So, Pm-01 (the second organic compound) and Ir(iPrpim)3 (the first organic compound) By controlling the interaction with Pm-01 (the second organic compound) and Ir(iPrpim)3 (the The ratio of exciplex formation with the organic compound (1) can be controlled, and as a result, the light-emitting element The color of emitted light can be controlled.

[0323] In addition, the light-emitting elements 5 to 8 have Ir(iPrpim)3 (first The ratio of the organic compound (the compound (I)) increases in the order of the light-emitting elements 5 to 6. In the light-emitting element 8, Pm-01 (the second organic compound) and Ir(iPrpim)3 (the first organic compound) were It has been found that the proportion of the broad emission derived from the exciplex formed with the compound) changes. Thus, by changing the proportion of Ir(iPrpim)3 (the first organic compound) in the light-emitting layer, the interaction between Pm-01 (the second organic compound) and Ir(iPrpim)3 (the first organic compound) can be controlled, and the formation ratio of the exciplex between Pm-01 (the second organic compound) and Ir(iPrp im)3 (the first organic compound) can be controlled. As a result, the emission color of the light-emitting device can be controlled.

[0324] Also, as shown in FIGS. 14 to 17, FIGS. 20 to 23, Table 3 and Table 4, the light-emitting devices 1 to 3, and the light-emitting devices 5 to 8 are driven at a lower driving voltage than the light-emitting device 4. Also, the light-emitting devices 1 to 3, and the light-emitting devices 5 to 8 have a higher power efficiency than the light-emitting device 4, and all showed a high power efficiency of 10 lm / W or more. Therefore, the light-emitting device of one aspect of the present invention having the first organic compound (Ir(iPrpim)3) and the second organic compound (Pm-01) is a light-emitting device with a low driving voltage and low power consumption.

[0325] Also, the light-emitting devices 2, 3, and the light-emitting devices 5 to 8 showed a high current efficiency of 20 cd / A or more. That is, the light-emitting device having the first organic compound (Ir(iPrpim)3), the second organic compound (Pm-01), and a light-emitting layer configuration having still another material (PCCP) is a light-emitting device showing a high current efficiency.

[0326] <CV measurement results> Next, the electrochemical characteristics (oxidation reaction characteristics and reduction reaction characteristics) of the above compounds were cycled. ​The measurements were performed using an electrochemical analyzer. - (manufactured by BAS Co., Ltd., model number: ALS model 600A or 600C) was used, Each compound was dissolved in N,N-dimethylformamide (DMF) and the solution was measured. In the measurement, the potential of the working electrode relative to the reference electrode was changed in an appropriate range to obtain the oxidation peaks. The redox potential of the reference electrode was -4.9 The peak potential is estimated to be 4 eV. The HOMO and LUMO levels of the compounds were calculated.

[0327] The CV measurement results showed that the oxidation potential of Pm-01 was 0.95 V and the reduction potential was -2.17 V. The HOMO level of Pm-01 calculated from the CV measurement was -5.89 eV, and the LUMO The LUMO level was -2.78 eV. This indicates that Pm-01 has a low LUMO level. It was also found that the oxidation potential of Ir(iPrpim)3 was 0.11 V. In addition, the HOMO level of Ir(iPrpim)3 calculated from CV measurements was -5.05 eV. This indicates that Ir(iPrpim)3 has a high HOMO level. In addition, the reduction potential of Ir(iPrpim)3 was low and no clear reduction peak was observed. Therefore, it is assumed that Ir(iPrpim)3 has a high LUMO level. The oxidation potential of PCCP was 0.685 V and the reduction potential was -2.98 V. The HOMO level of PCCP calculated from the above formula is -5.63 eV, and the LUMO level is -1.96 eV. It was V.

[0328] As described above, the LUMO level of Pm-01 is the same as that of PCCP and Ir(i Lower than the LUMO level of Prpim)3, the HOMO level of Ir(iPrpim)3 is higher than the HOMO level of CCP and the HOMO level of Pm-01. Therefore, when using this compound in the light-emitting layer, such as in light-emitting elements 1 to 3 and light-emitting elements 5 to 8, electrons and holes, which are carriers injected from a pair of electrodes, can be efficiently injected into Pm-01 and Ir(iPrpim)3 respectively, and an excited complex can be formed between Pm-01 and Ir(iPrpim)3. CCPのHOMO準位およびPm-01のHOMO準位より高い。そのため、発光素子1 乃至3、及び発光素子5乃至発光素子8のように、発光層に当該化合物を用いた場合、一 対の電極から注入されたキャリアである電子および正孔が、効率よくPm-01とIr( iPrpim)3にそれぞれ注入され、Pm-01とIr(iPrpim)3とで励起錯 体を形成することができる。

[0329] また、Pm-01とIr(iPrpim)3とで形成する励起錯体は、Pm-01にL UMO準位を有し、Ir(iPrpim)3にHOMO準位を有する励起錯体となる。ま た、Pm-01のLUMO準位とIr(iPrpim)3のHOMO準位とのエネルギー 差は、2.28eVである。これは、図24で示した発光素子8の電界発光スペクトルの ピーク波長から算出される発光エネルギー(2.28eV)と概ね一致している。また、 図18及び図24で示した発光素子1乃至3、及び発光素子5乃至発光素子7の電界発光 スペクトルの幅が広い波長領域の発光のエネルギーとも概ね一致している。このことから 、発光素子1乃至発光素子3、及び発光素子5乃至発光素子8の電界発光スペクトルは、 Pm-01及びIr(iPrpim)3で形成する励起錯体に基づく発光と、Ir(iP rpim)3に基づく発光とを有するスペクトルであるといえる。なお、励起錯体は、S 1準位とT1準位の差が小さいため、当該発光エネルギーが励起錯体のT1準位のエネル ギー(2.28eV)と見なすことができる。

[0330] <Measurement of T1 level> Next, in order to obtain the T1 level of the compound used in the light-emitting layer 130, Thin films of Pm-01 and PCCP were prepared by the above method, and the emission spectra of these thin films were was measured at low temperature (10K).

[0331] The measurements were performed using a micro PL microscope, LabRAM HR-PL (Horiba, Ltd.). The measurement temperature was 10K, and a He-Cd laser with a wavelength of 325 nm was used as the excitation light. A CCD detector was used.

[0332] In addition to the usual measurement of the emission spectrum, the emission spectrum was measured using a We also measured the time-resolved emission spectrum focusing on the long emission. Because the measurement was performed at low temperature (10K), the main emission component, In addition to fluorescence, some phosphorescence was also observed. In the optical spectrum measurement, phosphorescence was mainly observed. Measurements of Pm-01 and PCCP at low temperatures The time-resolved emission spectra are shown in FIG. 26 and FIG. 27, respectively.

[0333] From the results of the above measured emission spectrum, the phosphorescence component of the emission spectrum of Pm-01 is the most The wavelength of the peak (including the shoulder) on the short wavelength side was 451 nm. The shortest wavelength peak (including shoulder) of the phosphorescent component of the emission spectrum of is 46 It was 7nm.

[0334] Therefore, from the above peak wavelength, the T1 level of Pm-01 is 2.75 eV, and PC The T1 level of CP was calculated to be 2.66 eV.

[0335] <Absorption spectrum of guest material> Next, the absorption spectrum of Ir(iPrpim)3, the guest material used in the above light-emitting device, The measurement results are shown in Figure 28.

[0336] To measure the absorption spectrum, Ir(iPrpim)3 was dissolved in dichloromethane. The solution was prepared and the absorption spectrum was measured using a quartz cell. A UV-visible spectrophotometer (V550, manufactured by JASCO Corporation) was used. The absorption spectra of the quartz cell and the solvent were subtracted from the spectrum. The event was held in an atmosphere that maintained a high level of

[0337] As shown in Figure 28, the lowest energy in the absorption spectrum of Ir(iPrpim) The absorption edge on the long wavelength side is around 460 nm. From the above, the absorption edge was calculated, and the transition energy was estimated assuming a direct transition. The absorption edge of rpim3 is 474 nm, and the transition energy is calculated to be 2.61 eV. Since Ir(iPrpim)3 is a phosphorescent compound, the lowest energy absorption edge is This is an absorption band based on triplet MLCT transition. Therefore, the T1 The level is calculated to be 2.61 eV from the absorption edge.

[0338] From the above measurement results, the T1 level of PCCP and the T1 level of Pm-01 are Ir(iP The T1 level of Ir(iPrpim)3 is higher than that of Pm-01. The energy level of the exciplex formed with Ir(iPrpim)3 (2.28 eV), i.e. That is, it is larger than the T1 level of the exciplex. Therefore, Ir(iPrpim)3 and Pm-01 Both the emission of the exciplex formed by the reaction and the emission of Ir(iPrpim)3 were efficiently emitted. It is possible.

[0339] The energy level of the exciplex is the energy level between the LUMO level and the HOMO level of PCCP. The energy difference between the LUMO and HOMO levels of Pm-01 (3.67 eV) and Therefore, the formation of the exciplex reduces the driving voltage Therefore, a light-emitting element with low resistance can be obtained.

[0340] As described above, according to one embodiment of the present invention, a light-emitting element with high emission efficiency can be provided. According to one embodiment of the present invention, a light-emitting element that exhibits light emission with a wide emission spectrum is provided. According to one embodiment of the present invention, a light-emitting element with low driving voltage and low power consumption can be provided. It can be provided. EXAMPLES

[0341] In this example, a manufacturing example of a light-emitting element according to one embodiment of the present invention and characteristics of the light-emitting element will be described. The structure of the light-emitting device fabricated in this example is the same as that shown in FIG. 1. The details of the device structure are shown in Table 5. The structures and abbreviations of the compounds used are shown below.

[0342] [ka]

[0343] [Table 5]

[0344] <Fabrication of light-emitting element> A method for manufacturing the light-emitting element manufactured in this embodiment will be described below.

[0345] <Fabrication of light-emitting element 9> An ITSO film was formed on a glass substrate as an electrode 101 to a thickness of 70 nm. The electrode area of ​​the electrode 101 is 4 mm 2 (2mm x 2mm).

[0346] Next, a hole injection layer 111 made of DBT3P-II and molybdenum oxide was formed on the electrode 101. (MoO3) and the weight ratio (DBT3P-II:MoO3) was 1:0.5. The deposition was carried out to a thickness of 15 nm.

[0347] Next, a hole transport layer 112 was formed on the hole injection layer 111 by depositing PCCP to a thickness of 20 nm. The deposition was carried out so that

[0348] Next, a light-emitting layer 130 containing PCCP and 4,6mCzP2Pm and tris{2-[5-(2-methylphenyl)-4-(2,6-diisopropylphenyl (1,2,4-triazol-3-yl)-κN 2 ]phenyl-κC}iridiu Ir(mpptz-diPrp)3) and 400g of PCCP (weight ratio) ,6mCzP2Pm:Ir(mpptz-diPrp)3) is 1:0.3:0.06 The mixture was then co-evaporated to a thickness of 30 nm, followed by 4,6mCzP2Pm and , Ir(mpptz-diPrp)3, and the weight ratio (4,6mCzP2Pm:Ir(mp The ratio of ptz-diPrp3) was 1:0.06 and the thickness was 10 nm. In the light-emitting layer 130, Ir(mpptz-diPrp)3 was used as a guest material. The first organic compound is the dopant material, and 4,6mCzP2Pm is the host material (second organic compound). ).

[0349] Next, on the light-emitting layer 130, a 4,6mCzP2Pm film was deposited to a thickness of 1 0 nm, and BPhen was evaporated in sequence to a thickness of 15 nm. On the electron transport layer 118, LiF was evaporated to a thickness of 1 nm as the electron injection layer 119. I arrived.

[0350] 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.

[0351] Next, in a glove box with a nitrogen atmosphere, a glass substrate for sealing is By using an EL sealant to fix the organic material to a glass substrate, a light-emitting element 9 The specific method was the same as that for the light-emitting element 1. The light-emitting element 9 was obtained by the above steps. Ta.

[0352] <Fabrication of light-emitting element 10> The light emitting element 10 is the same as the light emitting element 9 shown above, except that the light emitting layer 130 and the electron transport layer 118 are formed in the same manner as in the light emitting element 9 shown above. The only difference was the manufacturing process, and the other steps were the same as those for the light-emitting element 9.

[0353] The light-emitting layer 130 of the light-emitting element 2 is made of PCCP, 35DCzPPy, and Ir(mppt z-diPrp)3 and the weight ratio (PCCP:35DCzPPy:Ir(mpptz-d iPrp)3) is 1:0.3:0.06 and the thickness is 30 nm. Co-evaporation of 35DCzPPy and Ir(mpptz-diPrp)3 was then performed by weight The ratio (35DCzPPy:Ir(mpptz-diPrp)3) is 1:0.06. In the light-emitting layer 130, Ir(mp ptz-diPrp)3 is the guest material (first organic compound), and 35DCzPPy is The host material is a second organic compound.

[0354] Next, on the light-emitting layer 130, 35DCzPPy was deposited to a thickness of 10 nm as the electron transport layer 118. Then, BPhen was evaporated in sequence to a thickness of 15 nm.

[0355] <Characteristics of light-emitting element> The luminance-current density characteristics of the fabricated light-emitting elements 9 and 10 are shown in FIG. 29 and luminance-voltage characteristics thereof are shown in FIG. The current efficiency vs. luminance characteristics are shown in Fig. 30, the power efficiency vs. luminance characteristics in Fig. 31, and the power efficiency vs. luminance characteristics in Fig. 32. The measurement method for each light-emitting element is the same as in Example 1, and the measurements were performed at room temperature (23° C.). The atmosphere was relaxed.

[0356] Also, 1000cd / m 2 The device characteristics of the light-emitting devices 9 and 10 in the vicinity are shown in Table 6. .

[0357] [Table 6]

[0358] Furthermore, the light-emitting elements 9 and 10 were each supplied with 2.5 mA / cm 2 A current was passed with a current density of The resulting electroluminescence spectra are shown in FIG.

[0359] As shown in FIG. 33, the full width at half maximum of the electroluminescence spectrum of the light-emitting element 9 and the light-emitting element 10 is The light-emitting element 9 has a wider electroluminescence width than the light-emitting element 10. The electroluminescence spectrum of the light-emitting element 9 is shown to be blue with a peak wavelength of 473 nm. The light-emitting element 10 emitted light of a broad wavelength range in green as well as red. showed luminescence mainly from the guest material Ir(mpptz - diPrp)3.

[0360] Next, a difference spectrum obtained by subtracting the electroluminescence spectrum of the light - emitting element 10 from the electroluminescence spectrum of the light - emitting element 9 normalized by the intensity at the peak wavelength of the light - emitting element 10 is shown in FIG. 34. As shown in FIG. 34, it was found that the light - emitting element 9 has luminescence on the longer - wavelength side in addition to the luminescence of the guest material shown by the electroluminescence spectrum of the light - emitting element 10. Also, the peak wavelength on the longer - wavelength side was around 520 nm. Further, the intensity ratio of the luminescence of the guest material of the light - emitting element 9 to the luminescence on the longer - wavelength side (luminescence derived from the guest material: luminescence on the longer - wavelength side) was 1:0.15. As will be shown later, 4,6mCzP2Pm and Ir(mpptz - diPrp)3 used in the light - emitting layer of the light - emitting element 9 are a combination that forms an exciplex. Therefore, it can be said that the reason why the light - emitting element 9 showed a broad spectral shape is that an exciplex is formed between 4,6mCzP2Pm and Ir(mpptz - diPrp)3, and luminescence from the exciplex is obtained.

[0361]

[0362] Also, as shown in FIGS. 29 to 32 and Table 6, the light - emitting element 9 is driven at a lower driving voltage than the light - emitting element 10. Also, the light - emitting element 9 shows high power efficiency. Therefore, the light - emitting element of one embodiment of the present invention having the first organic compound (Ir(mpptz - diPrp)3) and the second organic compound (4,6mCzP2Pm) is a light - emitting element with a low driving voltage and low power consumption.

[0363] <CV measurement results> Next, the electrochemical properties (oxidation and reduction properties) of the above compounds were examined by cycling. The measurement was performed by CV measurement. The measurement method was the same as in Example 1. In addition, the measurement results of PCCP can be seen in Example 1.

[0364] The CV measurements showed that the oxidation potential of 4,6mCzP2Pm was 0.95 V and the reduction potential was -2.0 6V. The HOMO level of 4,6mCzP2Pm calculated from CV measurements was -5 The luminescence energy level was 0.89 eV and the LUMO level was -2.88 eV. Pm was found to have a low LUMO level. Ir(mpptz-diPr p) The oxidation potential of 3 was 0.34 V and the reduction potential was -2.98 V. In addition, from the CV measurement, The calculated HOMO level of Ir(mpptz-diPrp)3 is -5.28 eV, and the LUMO The energy level was -1.96 eV. From this, Ir(mpptz-diPrp)3 is It was found that 35DCzPPy has a high HOMO level. The oxidation potential of 35DCzPPy is 0.9 The reduction potential was -2.56 V and the CV measurement showed that the 35DCzPPy The HOMO level was -5.90 eV and the LUMO level was -2.39 eV.

[0365] As mentioned above, the LUMO level of 4,6mCzP2Pm is the same as that of PCCP. and Ir(mpptz-diPrp)3, and the LUMO level of Ir(mpptz-di The HOMO level of Prp3 is the same as the HOMO level of PCCP and the H The OMO level is higher than that of the light-emitting element 9. The electrons and holes injected from the pair of electrodes are efficiently transported to the 2Pm and Ir(mpptz-diPrp)3, respectively, and 4,6mCzP2Pm and Ir(mpptz-diPrp)3 can form an exciplex.

[0366] In addition, the exciplex formed by 4,6mCzP2Pm and Ir(mpptz-diPrp)3 The compound has a LUMO level at 4,6mCzP2Pm and a LUMO level at Ir(mpptz-diPrp)3 The HOMO level of the exciplex is 4,6mCzP2Pm. The energy difference with the HOMO level of Ir(mpptz-diPrp)3 is 2.40 eV. This is because the light emitting element 9 shown in FIG. 33 emits light in a wide wavelength region of the electroluminescence spectrum. This is roughly consistent with the light energy (2.38 eV). The emission spectrum was generated using 4,6mCzP2Pm and Ir(mpptz-diPrp)3. The luminescence is based on an exciplex that emits light, and the luminescence is based on Ir(mpptz-diPrp)3. In addition, since the difference between the S1 and T1 levels of the exciplex is small, The emission energy is considered to be the energy of the T1 level of the exciplex (2.38 eV). can be done.

[0367] The LUMO level of 35DCzPPy is the same as that of PCCP and Ir(mp ptz-diPrp)3, and the LUMO level of Ir(mpptz-diPrp)3 The HOMO level is higher than that of PCCP and 35DCzPPy. Therefore, when the compound is used in the light-emitting layer as in the light-emitting element 10, The electrons and holes injected from the 35DCzPPy and Ir(mp ptz-diPrp)3 are injected into each

[0368] However, the energy difference between the LUMO level of 35DCzPPy and the HOMO level of Ir(mpptz - diPrp) 3 is as large as 2.90 eV. This is larger than the emission energy (2.6 1 eV) calculated from the peak wavelength of the electroluminescence spectrum of the light - emitting device 10 shown in FIG. 33. Therefore, it is more energetically stable for Ir(mpptz - diPrp)3 to be excited and emit light than to form an exciplex with 35DCzPPy. That is, 35DCzPPy and Ir(mpptz - diPrp)3 do not form a combination that forms an exciplex, and no emission based on the exciplex formed by 35DCzPPy and Ir(mpptz - diPrp)3 is observed from the light - emitting device 10. <Measurement of the T1 level> Next, in order to determine the T1 level of the compounds used in the light - emitting layer 130, the emission spectra of 4,6mCzP2Pm and 35DCzPPy were measured at a low temperature (10 K). The measurement method is the same as that in Example 1. Also, the measurement results of PCCP may be referred to Example 1. The time - resolved emission spectra of 4,6 mCzP2Pm and 35DCzPPy measured at low temperature are shown in FIGS. 35 and 36, respectively.

[0369] <Measurement of the T1 level> Next, to determine the T1 level of the compounds used in the light - emitting layer 130, the emission spectra of 4,6mCzP2Pm and 35DCzPPy were measured at low temperature (10 K). The measurement method is the same as in Example 1. Also, the measurement results of PCCP may be considered with reference to Example 1. The time - resolved emission spectra of 4,6 mCzP2Pm and 35DCzPPy measured at low temperature are shown in FIGS. 35 and 36, respectively. From the results of the above - measured emission spectra, the wavelength of the peak (including the shoulder) on the shortest - wavelength side of the phosphorescence component of the emission spectrum of 4,6mCzP2Pm was 459 nm. Also, the peak wavelength (including the shoulder) on the shortest - wavelength side of the phosphorescence component of the emission spectrum of 35DCzPPy was 451 nm.

[0370] From the results of the above - measured emission spectra, the wavelength of the peak (including the shoulder) on the shortest - wavelength side of the phosphorescence component of the emission spectrum of 4,6mCzP2Pm was 459 nm. Also, the peak wavelength (including the shoulder) on the shortest - wavelength side of the phosphorescence component of the emission spectrum of 35DCzPPy was 451 nm.

[0371]

[0371] Therefore, from the above peak wavelength, the T1 level of 4,6mCzP2Pm is 2.70 eV. The T1 level of 35DCzPPy was calculated to be 2.75 eV.

[0372] <Absorption spectrum of guest material> Next, the absorption of Ir(mpptz-diPrp)3, which is the guest material used in the light-emitting device, The measurement results of the absorption spectrum are shown in Fig. 37. The measurement method was the same as in Example 1.

[0373] As shown in Figure 37, the maximum peak in the absorption spectrum of Ir(mpptz-diPrp) The absorption edge on the low energy side (long wavelength side) is around 460 nm. From the data of the absorption edge, the transition energy was estimated assuming a direct transition. The absorption edge of Ir(mpptz-diPrp)3 is at 472 nm, and the transition energy is 2. The calculated value was 63 eV. Since Ir(mpptz-diPrp)3 is a phosphorescent compound, The lowest energy absorption edge is the absorption band based on triplet MLCT transition. Therefore, The T1 level of Ir(mpptz-diPrp)3 is calculated to be 2.63 eV from the absorption edge. can be.

[0374] From the above measurement results, the T1 level of PCCP and the T1 level of 4,6mCzP2Pm are as follows: The T1 level of Ir(mpptz-diPrp)3 is higher than that of Ir(mpptz-diPrp The T1 level of 4,6mCzP2Pm and Ir(mpptz-diPrp)3 is formed by The energy level of the corresponding exciplex (2.38 eV), i.e., higher than the T1 level of the exciplex Therefore, the compound formed by Ir(mpptz-diPrp)3 and 4,6mCzP2Pm Both the exciplex and Ir(mpptz-diPrp)3 emit efficiently. It is possible.

[0375] The energy level of the exciplex is the energy level between the LUMO level and the HOMO level of PCCP. Energy difference (3.67 eV), and LUMO and HOMO levels of 4,6mCzP2Pm The energy difference between the two (3.01 eV) is smaller than that of the exciplex. Therefore, a light-emitting element with low driving voltage can be obtained.

[0376] On the other hand, the T1 level of PCCP and the T1 level of 35DCzPPy are Ir(mpptz- The T1 level of Ir(mpptz-diPrp)3 is higher than that of Ir(mpptz-diPrp)3. , LUMO level of 35DCzPPy and HOMO level of Ir(mpptz-diPrp)3 The energy difference between these two is smaller than the 2.90 eV. p)3 and 35DCzPPy to form an exciplex, whereas Ir(mpptz-diPrp )3 is more energetically stable when excited and emits light. r(mpptz-diPrp)3 is a combination that does not form an exciplex, and light-emitting element 1 From 0, the exciplex formed by 35DCzPPy and Ir(mpptz-diPrp)3 No luminescence based on is observed.

[0377] <Time-resolved luminescence measurement> Next, a thin film sample having the combination of compounds used in the light-emitting layer was prepared and The transient luminescence characteristics were measured by photoluminescence analysis.

[0378] Thin film 1 is a thin film of 4,6mCzP2Pm and Ir(mpptz-diPrp )3, and the weight ratio (4,6mCzP2Pm:Ir(mpptz-diPrp)3) is 1: The layers were co-evaporated to a thickness of 50 nm and a thickness of 0.125.

[0379] Thin film 2 is a thin film of 35DCzPPy and Ir(mpptz-diPrp)3 on a quartz substrate. The weight ratio (35DCzPPy:Ir(mpptz-diPrp)3) is 1:0.12 5 and a thickness of 50 nm.

[0380] The measurements were performed using a picosecond fluorescence lifetime measurement system (Hamamatsu Photonics). In order to measure the lifetime of the luminescence exhibited by the thin film, the thin film was irradiated with a pulsed laser and the The decaying emission from the laser was measured in time resolution using a streak camera. A 337 nm nitrogen gas laser is used, and a 500 ps pulse laser is used to thin the film at a frequency of 10 Hz. By irradiating the film and accumulating the data measured repeatedly, data with a high S / N ratio can be obtained. The measurements were carried out at room temperature (an atmosphere maintained at 23°C).

[0381] The measured transient emission characteristics of Thin Film 1 and Thin Film 2 are shown in FIG.

[0382] The transient emission characteristics of thin film 2 showed a first-order decay that could be well fitted by a single exponential function. On the other hand, the transient emission characteristics of thin film 1 contain a delayed emission component in addition to the initial emission component. In other words, it was found that the thin film 1 emits light consisting of at least two components. was suggested.

[0383] Next, the emission spectrum of the early emission component and the emission spectrum of the delayed emission component of the thin film 1 are The emission spectrum of the initial emission component is shown in Figure 39. The emission spectrum of the delayed emission component is from 0.9 μs to 44 μs. 4 shows emission spectra obtained by measuring the emission from thin film 1 at

[0384] As shown in FIG. 39, the emission spectrum of the early emission component and the delayed emission component of the thin film 1 are The spectra show different spectral shapes, and the emission of the delayed emission component is different from that of the early emission component. The emission spectrum shows an emission wavelength longer than that of the light.

[0385] The emission energy ( 2.39 eV) is formed by 4,6mCzP2Pm and Ir(mpptz-diPrp)3 The energy of the exciplex is roughly consistent with that of the corresponding exciplex. In addition, the exciplex exhibits thermally activated delayed fluorescence. The delayed emission components of thin film 1 are 4,6mCzP2Pm and Ir(m This emission is based on an exciplex with pptz-diPrp3.

[0386] As described above, the light-emitting element 9 manufactured in this example is a combination that forms an exciplex. The first organic compound (Ir(mpptz-diPrp)3) and the second organic compound (4,6 mCzP2Pm).

[0387] As described above, according to one embodiment of the present invention, a light-emitting element with high emission efficiency can be provided. According to one embodiment of the present invention, a light-emitting element that exhibits light emission with a wide emission spectrum is provided. According to one embodiment of the present invention, a light-emitting element with low driving voltage and low power consumption can be provided. It can be provided. EXAMPLES

[0388] Example 1 In this example, light-emitting characteristics of a thin film that can be used for a light-emitting element of one embodiment of the present invention will be described. The structures and abbreviations of the compounds used in the examples are shown below.

[0389] [ka]

[0390] <Preparation of thin film samples> Thin film 3 was prepared by dissolving m-MTDATA and bis[2-methyl-3-(6-tetramethylphenyl)-2-(tetramethylphenyl)-1,2-dimethylphenyl] ... rt-Butyl-4-pyrimidinyl-κN 3 )Pyridyl-κC](2,4-pentanediona To-κ 2 O,O') Iridium(III) (abbreviation: Ir(tBumpypm)2(aca c)) and the weight ratio (m-MTDATA:Ir(tBumpypm)2(acac)) They were co-evaporated so that the ratio was 1:0.01 and the thickness was 50 nm.

[0391] For thin film 4, m-MTDATA and Ir(tBumpypm)2(ac ac) and the weight ratio (m-MTDATA:Ir(tBumpypm)2(acac)) The layers were co-evaporated at a ratio of 1:0.25 to a thickness of 50 nm.

[0392] As the thin film 5, mCP, Ir(tBumpypm)2(acac), and The weight ratio (mCP:Ir(tBumpypm)2(acac)) is 1:0.01. The layers were co-evaporated to a thickness of 50 nm.

[0393] As the thin film 6, mCP, Ir(tBumpypm)2(acac), and The weight ratio (mCP:Ir(tBumpypm)2(acac)) is 1:0.25. The layers were co-evaporated to a thickness of 50 nm.

[0394] <Emission spectrum> The emission spectra of the above-prepared thin films 3 to 6 were measured. The measurement of the emission spectrum was , using a PL-EL measuring device (manufactured by Hamamatsu Photonics). The measurement was also carried out at room temperature (atmosphere maintained at 23 °C). The measurement results are shown in FIGS. 40 and 41.

[0395] From thin films 5 and 6, green emission presented by the phosphorescent compound Ir(tBumpypm)2(acac ) was observed. On the other hand, from thin films 3 and 4, in addition to the emission of Ir(tBump ypm)2(acac), emission having a wide spectral shape on the long-wavelength side was observed.

[0396] <Time-resolved luminescence measurement> Next, time-resolved luminescence measurements of thin films 3 to 6 were performed. A picosecond fluorescence lifetime measurement system (manufactured by Hamamatsu Photonics) was used for the measurement. The measurement method is the same as that in Example 2.

[0397] The transient luminescence characteristics of thin films 3 to 6 obtained by the measurement are shown in FIGS. 42 and 43.

[0398] The transient luminescence characteristics of thin films 5 and 6 showed a decay curve close to a single exponential function. On the other hand, it was found that the transient luminescence characteristics of thin films 3 and 4 included a delayed luminescence component in addition to the initial luminescence component. That is, it was suggested that thin films 3 and 4 have luminescence composed of at least two components.

[0399] <CV measurement results> Next, the electrochemical properties (oxidation reaction characteristics and reduction reaction characteristics) of the above compounds were measured by cyclic voltammetry (CV). The measurement method is the same as that in Example 1.

[0400] As a result of CV measurement, the oxidation potential of m-MTDATA was 0.04 V and the reduction potential was -2.72 V. The HOMO level of m-MTDATA calculated from the CV measurement was -4.98e V, LUMO level was -2.22 eV. From this, m-MTDATA has high It was found that it has a HOMO level. In addition, Ir(tBumpypm)2(acac) The oxidation potential was 0.91 V and the reduction potential was -2.04 V. The HOMO level of Ir(tBumpypm)2(acac) is -5.85 eV, and the LUMO The level was -2.90 eV. This indicates that Ir(tBumpypm)2(acac ) was found to have a low LUMO level. The oxidation potential of mCP was 0.97 V. The HOMO level of mCP calculated from CV measurements was -5.91 eV. In addition, since the reduction potential of mCP was low and no clear reduction peak was observed, is predicted to have a high LUMO level.

[0401] As mentioned above, the LUMO level of Ir(tBumpypm)2(acac) is m-MT The HOMO level of Ir(tBumpypm)2(acac) is lower than the LUMO level of DATA. The level is lower than the HOMO level of m-MTDATA. )2(acac) and m-MTDATA can form an exciplex. be.

[0402] In addition, the excitation current formed by Ir(tBumpypm)2(acac) and m-MTDATA The complex has a LUMO level at Ir(tBumpypm)2(acac) and m-MTDA It becomes an exciplex with a HOMO level in TA. Also, Ir(tBumpypm)2(ac The energy difference between the LUMO level of ac) and the HOMO level of m-MTDATA is 2.08 eV. This is approximately consistent with the emission energy (2.06 eV) calculated from the peak wavelength of the emission spectrum of thin film 4 shown in FIG. 40. From this, the emission spectra of thin films 3 and 4 are spectra having emission based on an exciplex formed by Ir(tBumpypm)2(acac) and m-MTDATA and emission based on Ir(tBumpypm)2(acac). Note that since the difference between the S1 level and the T1 level of the exciplex is small, the emission energy can be regarded as the energy of the T1 level of the exciplex (2.06 eV). In addition, the HOMO level of mCP is lower than the HOMO level of Ir(tBumpypm)2(acac). Therefore, mCP and Ir(tBumpypm)2(acac) are a combination that does not form an exciplex, and no emission based on an exciplex formed by mCP and Ir(tBump ypm)2(acac) is observed from thin films 5 and 6.

[0403]

[0404] <Measurement of T1 level> Next, in order to determine the T1 level of the compounds used in thin films 3 and 4, the emission spectrum of m-MTDATA was measured at low temperature (10 K). The measurement method is the same as in Example 1 . The time-resolved emission spectrum of m-MTDATA measured at low temperature is shown in FIG. 44.

[0405] From the results of the above-measured emission spectrum, the wavelength of the peak on the shortest wavelength side (including the shoulder) of the phosphorescence component of the emission spectrum of m-MTDATA was 484 nm. Therefore ​​​​​​​From the above peak wavelength, the T1 level of m-MTDATA was calculated to be 2.56 eV.

[0406] <Absorption spectrum of guest material> Next, the guest material used in thin films 3 and 4, Ir(tBumpypm)2(ac The measurement results of the absorption spectrum of a) are shown in FIG. 45. The measurement method was the same as in Example 1. It is.

[0407] As shown in Figure 45, in the absorption spectrum of Ir(tBumpypm)2(acac), The lowest energy (longest wavelength) absorption edge in the absorption spectrum is around 490 nm. From the spectral data, the absorption edge was obtained and the transition energy was estimated assuming a direct transition. As a result, the absorption edge of Ir(tBumpypm)2(acac) is 496 nm, and the transition energy The energy was calculated to be 2.50 eV. Ir(tBumpypm)2(acac) is phosphorescent. Since it is a compound, the lowest energy absorption edge is the absorption band based on the triplet MLCT transition. Therefore, the T1 level of Ir(tBumpypm)2(acac) is This gives a calculated value of 2.50 eV.

[0408] From the above measurement results, the T1 level of m-MTDATA is Ir(tBumpypm)2( The T1 level of Ir(tBumpypm)2(acac) is higher than that of Ir(tBumpypm)2(acac). , LUMO level of Ir(tBumpypm)2(acac) and HOM of m-MTDATA The energy difference with the O level (2.08 eV), or Ir(tBumpypm)2(ac The emission energy of the exciplex formed by ac) and m-MTDATA (2.06 eV). That is, it is higher than the T1 level of the exciplex. Therefore, Ir(tBumpypm)2(acac ) and m-MTDATA, and the emission of the exciplex formed by Ir(tBumpypm)2( acac) can be emitted efficiently.

[0409] As described above, the thin films 3 and 4 prepared in this embodiment are combinations that form exciplexes. The first organic compound (Ir(tBumpypm)2(acac)) and the second organic compound The compound (m-MTDATA) is preferably used for the light-emitting element of one embodiment of the present invention. There can be.

[0410] As described above, according to one embodiment of the present invention, a light-emitting element that exhibits light emission with a wide emission spectrum is provided. It is possible. [Explanation of symbols]

[0411] 100 EL layer 101 Electrode 101a Conductive layer 101b Conductive layer 102 electrode 103 Electrode 103a Conductive layer 103b Conductive layer 104 Electrode 104a conductive layer 104b Conductive layer 106 Light Emitting Unit 108 Light Emitting Unit 111 Hole injection layer 112 Hole transport layer 113 Electron transport layer 114 Electron injection layer 115 Charge generation layer 116 Hole injection layer 117 Hole transport layer 118 Electron transport layer 119 Electron injection layer 123B Light-emitting layer 123G Light-emitting layer 123R Light-emitting layer 130 Light-emitting layer 131 Guest Materials 132 Host Materials 133 Host Materials 145 Bulkhead 150 Light emitting element 170 Light-emitting layer 170a Light-emitting layer 170b Light-emitting layer 200 boards 220 Substrate 221B area 221G area 221R area 222B area 222G area 222R area 223 Light blocking layer 224B Optical elements 224G Optical Elements 224R Optical elements 250 Light emitting element 260 Light-emitting element 262a Light emitting element 262b Light emitting element 600 display device 601 Signal line driver circuit section 602 Pixel section 603 Scanning line driving circuit section 604 Sealing substrate 605 Sealing material 607 area 608 Wiring 609 FPC 610 Element Substrate 611 Transistor 612 Transistor 613 Lower electrode 614 Bulkhead 616 EL layer 617 Upper electrode 618 Light-emitting element 621 Optical Elements 622 Light blocking layer 623 Transistor 624 Transistor 1001 Board 1002 Undercoat insulating film 1003 Gate insulating film 1006 Gate electrode 1007 Gate electrode 1008 Gate electrode 1020 Interlayer insulating film 1021 Interlayer insulating film 1022 Electrode 1024B Lower electrode 1024G bottom electrode 1024R lower electrode 1025 Bulkhead 1026 Upper electrode 1028 EL layer 1029 Sealing layer 1031 Sealing substrate 1032 Sealing material 1033 Base material 1034B Colored layer 1034G colored layer 1034R colored layer 1035 Light blocking layer 1036 Overcoat layer 1037 Interlayer insulating film 1040 Pixel section 1041 Drive circuit section 1042 Periphery 3000 Light Emitting Device 3001 Substrate 3003 Substrate 3005 Light emitting element 3007 Sealing area 3009 Sealing area 3011 area 3013 area 3018 Desiccant 8501 Lighting equipment 8502 Lighting equipment 8503 Lighting equipment 8504 Lighting equipment 9000 Chassis 9001 Display section 9003 Speaker 9005 Operation key 9006 Connection terminal 9007 Sensor 9008 Microphone 9050 Operation button 9051 Information 9052 Information 9053 Information 9054 Information 9055 Hinge 9100 Mobile Information Terminal 9101 Portable information terminal 9102 Portable information terminal 9200 Mobile Information Terminal 9201 Portable information terminals

Claims

1. A light-emitting device having a light-emitting layer, the light-emitting layer includes a first organic compound and a second organic compound, a HOMO level of the first organic compound is lower than a HOMO level of the second organic compound; a LUMO level of the first organic compound is lower than a LUMO level of the second organic compound; the first organic compound and the second organic compound form an exciplex; the first organic compound has a function of converting triplet excitation energy into luminescence, A light-emitting element, wherein the lowest excited triplet level of the second organic compound is equal to or higher than the lowest excited triplet level of the first organic compound.

2. A light-emitting device having a light-emitting layer, the light-emitting layer includes a first organic compound and a second organic compound, a HOMO level of the first organic compound is lower than a HOMO level of the second organic compound; a LUMO level of the first organic compound is lower than a LUMO level of the second organic compound; the first organic compound and the second organic compound form an exciplex; the first organic compound has a function of converting triplet excitation energy into luminescence, the second organic compound has at least one of a π-electron rich heteroaromatic skeleton or an aromatic amine skeleton, A light-emitting element, wherein the lowest excited triplet level of the second organic compound is equal to or higher than the lowest excited triplet level of the first organic compound.

3. In claim 2, The second organic compound has a π-electron rich heteroaromatic skeleton and an aromatic amine skeleton.

4. In claim 2 or 3, The light-emitting device, wherein the aromatic amine skeleton is a tertiary amine.

5. In claim 2 or 3, The aromatic amine skeleton is a triarylamine skeleton.

6. A light-emitting device having a light-emitting layer, the light-emitting layer includes a first organic compound and a second organic compound, a HOMO level of the first organic compound is lower than a HOMO level of the second organic compound; a LUMO level of the first organic compound is lower than a LUMO level of the second organic compound; the first organic compound and the second organic compound form an exciplex; the first organic compound has a function of converting triplet excitation energy into luminescence, the second organic compound has one or more selected from a furan skeleton, a thiophene skeleton, and a pyrrole skeleton; A light-emitting element, wherein the lowest excited triplet level of the second organic compound is equal to or higher than the lowest excited triplet level of the first organic compound.

7. In claim 6, The light-emitting device, wherein the furan skeleton is a dibenzofuran skeleton.

8. In claim 6 or 7, The light-emitting device, wherein the thiophene skeleton is a dibenzothiophene skeleton.

9. In any one of claims 6 to 8, The light-emitting element, wherein the pyrrole skeleton is an indole skeleton or a carbazole skeleton.

10. In any one of claims 6 to 8, The light-emitting element, wherein the pyrrole skeleton is a 3-(9-phenyl-9H-carbazol-3-yl)-9H-carbazole skeleton.

11. In any one of claims 1 to 10, a lowest excited triplet level of the first organic compound and a lowest excited triplet level of the second organic compound are higher than an energy calculated from a peak wavelength of an emission spectrum of the exciplex.

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

13. A display device according to claim 12; At least one of a housing or a touch sensor; An electronic device having the

14. A light-emitting element according to any one of claims 1 to 11, At least one of a housing or a touch sensor; A lighting device having the above structure.

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