Light-emitting device

Abstract

To provide a light-emitting device having high luminous efficiency.SOLUTION: The light-emitting device includes a first organic compound and a second organic compound. The first and second organic compounds form an exciplex. The first organic compound is a compound that exhibits phosphorescence but not fluorescence at any temperature from a low temperature to room temperature, and the luminous quantum yield of the first organic compound at room temperature is 0% or more and 40% or less. The light emitted from the light-emitting device includes light emitted from the exciplex formed by the first organic compound and the second organic compound.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

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

[0003] In recent years, electroluminescence (EL) The basic structure of these light-emitting devices is as follows: The device has a structure in which a layer containing a light-emitting 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 it has excellent visibility and It has the advantage of not requiring a light source and consuming little power. It also has the advantage of high response speed.

[0005] An EL device that uses an organic compound as the luminescent material and contains the luminescent organic compound between a pair of electrodes In the case of a light-emitting element (for example, an organic EL element) having a layer, 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 form a luminescent 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 Condition (T * ) and emission from the singlet excited state is fluorescence, and emission from the triplet excited state is phosphorescence. The statistical generation rate of these light sources in a light-emitting device is S * :T * = Therefore, compared to a light-emitting element using a compound that emits fluorescence (a fluorescent compound), Light-emitting elements that use phosphorescent compounds (phosphorescent compounds) have higher luminous efficiency. Therefore, it is possible to convert the energy of the triplet excited state into light emission. In recent years, the development of light-emitting devices using phosphorescent compounds has been actively pursued. In this study, we investigated in detail the temperature dependence of the luminescence quantum yield of phosphorescent Ir complexes. We are investigating the relationship between the molecular structure of Ir complexes and their luminescence quantum yield, as well as the reasons for this.

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

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

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-45184 [Non-patent literature]

[0010] [Non-Patent Document 1] T. Sajoto and 5 others, Journal of the American Chemical Society, vol. 131, 9813 (2009) Summary of the Invention [Problem to be solved by the invention]

[0011] 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 using exciplexes as materials, the triplet excited state can be efficiently converted to the singlet excited state. Therefore, there is a need to develop a method for efficiently generating these elements and further improving the luminous efficiency of light-emitting elements.

[0012] Therefore, one object of one embodiment of the present invention is to provide a light-emitting element with high emission efficiency. Another object of one embodiment of the present invention is to provide a light-emitting element with low driving voltage. Another embodiment of the present invention is to provide a light-emitting element with reduced power consumption. Another object of the present invention is to provide a light-emitting element with high reliability. Another object of one embodiment of the present invention is to provide a novel light-emitting element. An object of one embodiment of the present invention is to provide a novel light-emitting device. An object of one embodiment of the present invention is to provide a novel display device.

[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 the function of

[0015] Another embodiment of the present invention is a light-emitting element having a light-emitting layer, in which the light-emitting layer is formed of a first organic compound. and a second organic compound, wherein one of the first organic compound and the second organic compound The LUMO level of the first organic compound and the second organic compound is higher than the LUMO level of the other. and the HOMO level of one of the first organic compound and the second organic compound is 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; The first organic compound is a combination capable of forming an exciplex with the second organic compound, The triplet excitation energy can be converted into luminescence at temperatures between 77K and 313K. The first organic compound has a luminescence quantum yield of 0% or more and 40% or less at room temperature. The light emitting layer emits light emitted by the exciplex.

[0016] Another embodiment of the present invention is a light-emitting element having a light-emitting layer, in which the light-emitting layer includes a first and a second organic compound, The LUMO level of one of the organic compounds is higher than the LUMO level of the other of the first organic compound and the second organic compound. The HOMO level of one of the first organic compound and the second organic compound is The HOMO level of the first organic compound is equal to or higher than the HOMO level of the second organic compound. and the second organic compound are a combination capable of forming an exciplex, and the first organic compound does not exhibit fluorescence and exhibits phosphorescence at temperatures between 77K and 313K. The first organic compound has a luminescence quantum yield of 0% or more and 40% or less at room temperature. The light emitting layer emits light emitted by the exciplex.

[0017] Another embodiment of the present invention is a light-emitting element having a light-emitting layer, in which the light-emitting layer includes a first and a second organic compound, The LUMO level of one of the organic compounds is higher than the LUMO level of the other of the first organic compound and the second organic compound. The HOMO level of one of the first organic compound and the second organic compound is The HOMO level of the first organic compound is equal to or higher than the HOMO level of the second organic compound. and the second organic compound are a combination capable of forming an exciplex, and the first organic compound is , Ru, Rh, Pd, Os, Ir, or Pt, and the first organic compound is 0% at room temperature. The luminescence quantum yield of the luminescence layer is equal to or greater than 40%, and the luminescence emitted by the luminescence layer is equal to or greater than the luminescence emitted by the exciplex. It is a light emitting element having

[0018] In each of the above-mentioned structures, the lowest excited triplet energy level of the first organic compound is It is preferable that the energy level is equal to or higher than the lowest excited triplet energy level of the organic compound.

[0019] In each of the above structures, the first organic compound preferably contains Ir. The organic compound of 1 has a ligand that coordinates with Ir, and the ligand has a nitrogen-containing five-membered heterocyclic skeleton. This is preferable.

[0020] 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.

[0021] In each of the above structures, the exciplex has a higher luminous efficiency than that of the first organic compound. It is preferable that the organic EL element has a function of emitting light with a higher luminous efficiency than the organic EL element.

[0022] Another embodiment of the present invention is a light-emitting element having any of the above structures, a color filter or a transistor, and a light-emitting element. and at least one of a first transistor and a second transistor. The electronic device includes the display device and at least one of a housing and a touch sensor. Another embodiment of the present invention is a light-emitting element having any of the above structures, a housing, or a touch sensor. Another embodiment of the present invention is a lighting device having a light-emitting element. Not only optical devices but also electronic devices having light-emitting devices are included in the category. The light-emitting device in this context refers to an image display device or a light source (including a lighting device). Optical element connector, such as FPC (Flexible Printed Circuit) t), TCP (Tape Carrier Package) mounted display module 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. [Effects of the Invention]

[0023] 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 with low driving voltage can be provided. According to one embodiment of the present invention, a light-emitting element with reduced power consumption can be provided. According to one embodiment of the present invention, a light-emitting element with high reliability can be provided. Further, a novel light-emitting element can be provided. According to one embodiment of the present invention, a novel display device can be provided. It can be provided.

[0024] The description of these effects does not preclude the existence of other effects. It is not necessary to have all of these effects. Effects other than these may be included in the description. It is obvious from the description of the specification, drawings, claims, etc. From this, it is possible to extract other effects. [Brief explanation of the drawings]

[0025] [Figure 1] 1A and 1B are schematic cross-sectional views of a light-emitting element according to one embodiment of the present invention. [Figure 2] 1A and 1B are schematic cross-sectional views of a light-emitting layer of a light-emitting element of one embodiment of the present invention and a diagram illustrating the correlation between energy levels. [Figure 3] 1A and 1B are schematic cross-sectional views of a light-emitting layer of a light-emitting element of one embodiment of the present invention and a diagram illustrating the correlation between energy levels. [Figure 4] 1A and 1B are diagrams illustrating the correlation of energy levels of a light-emitting layer of a light-emitting element according to one embodiment of the present invention. [Figure 5] 1A and 1B are schematic cross-sectional views of a light-emitting element according to one embodiment of the present invention. [Figure 6] 1A and 1B are schematic cross-sectional views of a light-emitting element according to one embodiment of the present invention. [Figure 7] 1A and 1B are schematic cross-sectional views 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 view 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] FIG. 1 is a perspective view illustrating a display module of one embodiment of the present invention. [Figure 12] 1A to 1C illustrate electronic devices of one embodiment of the present invention. [Figure 13] 1A to 1C illustrate a display device according to one embodiment of the present invention. [Figure 14] 1A to 1C illustrate a lighting device according to one embodiment of the present invention. [Figure 15] FIG. 10 is a graph showing luminance-current density characteristics of a light-emitting element according to an example. [Figure 16] FIG. 10 is a graph showing luminance-voltage characteristics of a light-emitting element according to an example. [Figure 17] FIG. 10 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 18] FIG. 10 is a graph showing power efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Figure 19]FIG. 10 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 20] 10A and 10B are graphs illustrating electroluminescence spectra of light-emitting elements according to Examples. [Figure 21] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 22] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 23] 1A and 1B are diagrams illustrating absorption spectra and emission spectra of compounds according to an example. [Figure 24] FIG. 10 is a graph showing luminance-current density characteristics of a light-emitting element according to an example. [Figure 25] FIG. 10 is a graph showing luminance-voltage characteristics of a light-emitting element according to an example. [Figure 26] FIG. 10 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 27] FIG. 10 is a graph showing power efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Figure 28] FIG. 10 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 29] 10A and 10B are graphs illustrating electroluminescence spectra of light-emitting elements according to Examples. [Figure 30] FIG. 2 is a diagram illustrating absorption spectra of compounds according to an example. [Figure 31] FIG. 10 is a graph showing luminance-current density characteristics of a light-emitting element according to an example. [Figure 32] FIG. 10 is a graph showing luminance-voltage characteristics of a light-emitting element according to an example. [Figure 33] FIG. 10 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 34] FIG. 10 is a graph showing power efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Figure 35] FIG. 10 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 36] 10A and 10B are graphs illustrating electroluminescence spectra of light-emitting elements according to Examples. [Figure 37] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 38] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 39] FIG. 10 is a diagram illustrating the emission spectrum of a thin film according to an example. [Figure 40] FIG. 10 is a graph showing luminance-current density characteristics of a light-emitting element according to an example. [Figure 41] FIG. 10 is a graph showing luminance-voltage characteristics of a light-emitting element according to an example. [Figure 42] FIG. 10 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 43] FIG. 10 is a graph showing power efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Figure 44] FIG. 10 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 45] 10A and 10B are graphs illustrating electroluminescence spectra of light-emitting elements according to Examples. [Figure 46] 1A and 1B are diagrams illustrating absorption spectra and emission spectra of compounds according to an example. [Figure 47] FIG. 10 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 48] 10A and 10B are graphs illustrating electroluminescence spectra of light-emitting elements according to Examples. [Figure 49] FIG. 10 is a graph showing transient EL curves of a light-emitting element according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the above description, and the embodiments and details thereof may be modified without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the following embodiments and examples. The present invention should not be construed as being limited to the contents of the examples.

[0027] In addition, the position, size, range, etc. of each component shown in the drawings etc. are not necessarily shown in order to facilitate understanding. It may not represent the actual position, size, range, etc. Therefore, the disclosed invention The position, size, range, etc. are not necessarily limited to those disclosed in the drawings, etc.

[0028] In addition, in this specification, ordinal numbers such as 1st, 2nd, etc. are used for convenience, In some cases, the order of processes or layers may not be indicated. For example, "first" may be replaced with "second" or " can be appropriately replaced with "third" etc. The ordinal numbers used to identify an aspect of the present invention may not match. be.

[0029] In addition, in this specification and the like, when explaining the configuration of the invention using drawings, the same The reference numerals may be commonly used even among different drawings.

[0030] 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

[0031] In this specification and the like, the singlet excited state (S * ) is a single atom with excitation energy The S1 level is the lowest singlet excited energy level. , the lowest excited energy level of the singlet state (S1 state). term excited state (T * ) is a triplet state with excitation energy. The lowest triplet excited energy level is the lowest triplet excited state (T1 In this specification, the term "singlet excited state" is used to refer to the excited energy level of the singlet excited state. Even when written as S1 state and singlet excited energy level, Also, the triplet excited state and triplet excited energy level are sometimes used. Even in this case, it may refer to the T1 state and T1 level.

[0032] In this specification and the like, a fluorescent compound is 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 excited into a triplet 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 a compound that can convert triplet excitation energy into visible light.

[0033] 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.

[0034] In this specification, the blue wavelength range is 400 nm or more and 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 light is emitted in this wavelength region. It has at least one emission spectrum peak. The red wavelength region is 580 nm. The red light has at least one emission spectrum in the wavelength range of 680 nm or more and 680 nm or less. It has a peak.

[0035] (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.

[0036] <Configuration example 1 of light-emitting element> First, the structure of a light-emitting element of one embodiment of the present invention will be described below with reference to FIG.

[0037] FIG. 1 is a schematic cross-sectional view of a light-emitting element 150 according to one embodiment of the present invention.

[0038] The light emitting element 150 has a pair of electrodes (electrode 101 and electrode 102), and The EL layer 100 has at least a light-emitting layer 130. .

[0039] The EL layer 100 shown in FIG. 1 includes a hole injection layer 111, a hole transport layer 121, a light emitting layer 130, and a hole transport layer 131. It has functional layers such as layer 112 , electron transport layer 118 , and electron injection layer 119 .

[0040] In this embodiment, of the pair of electrodes, electrode 101 is an anode, and electrode 1 Although the description will be given assuming that O2 is a cathode, the configuration of the light emitting element 150 is not limited to this. The electrode 101 is the cathode, the electrode 102 is the anode, and the layers between the electrodes are stacked in the reverse order. That is, from the anode side, the hole injection layer 111, the hole transport layer 112, and the light emitting layer 113 may be arranged in this order. The light-emitting layer 130, the electron transport layer 118, and the electron injection layer 119 may be stacked in this order. .

[0041] The configuration of the EL layer 100 is not limited to the configuration shown in FIG. 1. At least one layer 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 hole or electron transport, inhibit hole or electron transport, or or a structure having a functional layer having a function of suppressing a quenching phenomenon due to an electrode. The functional layers may each be a single layer or may be a laminate of multiple layers. It is also possible.

[0042] <Light-emitting mechanism of light-emitting element 1> Next, the light emitting mechanism of the light emitting layer 130 will be described below.

[0043] In the light-emitting element 150 of one embodiment of the present invention, a pair of electrodes (electrode 101 and electrode 102) By applying a voltage between the cathode and the anode, electrons flow from the cathode and holes flow from the anode. The electrons and holes are then injected into the EL layer 100, causing a current to flow. Excitons are formed by the recombination of carriers (electrons and holes). The ratio of singlet excitons to triplet excitons (hereafter referred to as the exciton generation probability) is statistically The probability of generating singlet excitons is 1:3, which means that the rate of generating singlet excitons is 25%. Since the rate at which triplet excitons are generated is 75%, it is necessary to make triplet excitons contribute to light emission. However, it is important to improve the light emitting efficiency of the light emitting device. The light-emitting material used has the function of converting triplet excitation energy into light emission. It is preferable that the material is one that can

[0044] Phosphorescence is a material that has the function of converting triplet excitation energy into luminescence. Examples of compounds that can emit light include compounds that can emit light (hereinafter also referred to as phosphorescent compounds). In this context, a phosphorescent compound is a compound that emits light in a temperature range from a low temperature (for example, 77 K) to room temperature (i.e., Compounds that exhibit phosphorescence but do not exhibit fluorescence at any temperature (77K or higher and 313K or lower) In order for phosphorescent compounds to efficiently convert triplet excitation energy into light, When the phosphorescent compound has a heavy atom, the spin-orbit interaction The interaction between the spin angular momentum and orbital angular momentum of the electron allows the electron to be in the singlet and triplet states. In phosphorescent compounds, the intersystem crossing between the singlet ground state and the triplet excited state is promoted. That is, the transition between the singlet ground state and the triplet excited state of the phosphorescent compound is allowed. The transition probability between the two states increases, which increases the efficiency of the emission and the probability of absorption associated with the transition. To achieve this, the phosphorescent compound must contain a metal element with a large spin-orbit interaction. It is preferable that the metal oxide contains a transition metal element, and particularly a platinum group element (ruthenium ( Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (I It is preferable to have iridium (Ir) or platinum (Pt), among others. This can increase the transition probability involved in the direct transition between the singlet ground state and the triplet excited state. Very desirable.

[0045] In addition, materials that have the function of converting triplet excitation energy into luminescence include and thermally activated delayed fluorescence (TADF) materials. The difference between the S1 and T1 levels is small, and reverse intersystem crossing occurs between triplet excitation energy and singlet excitation energy. It is a material that has the function of converting energy into excitation energy. Therefore, the triplet excitation energy is converted to singlet excitation energy by a small amount of thermal energy. It is possible to convert (reverse intersystem crossing) and efficiently exhibit luminescence (fluorescence) from the singlet excited state. It is possible to form an exciplex (exciplex or excip lex) has an extremely small difference between the S1 and T1 levels, and the triplet excitation energy The compound functions as a thermally activated delayed fluorescent material that can convert a part of the emitted light into light.

[0046] Therefore, in one embodiment of the present invention, a light-emitting material for the light-emitting layer 130 is formed using two kinds of substances. In addition, one of the two substances is in a triplet excited state. A compound having the function of converting energy into luminescence is used.

[0047] Furthermore, when a compound with a low luminescence quantum yield is used as one of the compounds forming the exciplex, In either case, the triplet excitation energy can be converted into luminescence by the single compound. When a compound having a function capable of emitting light is used, an exciplex with high luminescence efficiency is formed. The present inventors have found that it is possible to form an exciplex by using a compound that is When compounds containing heavy atoms are used, spin-orbit interaction (the relationship between the spin angular momentum and orbital angle of electrons) Intersystem crossing between the singlet and triplet states is facilitated by the interaction of the electrons with the electron momentum. That is, reverse intersystem crossing from the triplet excited state to the singlet excited state is promoted in the exciplex. This increases the probability of generating a singlet excited state in the exciplex. When an exciplex emits light from a singlet excited state, it is necessary to obtain an exciplex that emits light efficiently. On the other hand, the transition probability from the triplet excited state to the singlet ground state can be improved. Therefore, even when the exciplex emits light from the triplet excited state, it can emit light efficiently. It is possible to form an exciplex that emits light from any excited state. (The energies of the singlet and triplet states of the exciplex are close to each other.) However, the excitation (emission) lifetime of the exciplex is longer than that of a typical thermally activated delayed fluorescent material. This leads to the suppression of degradation from the excited state. Therefore, it is possible to obtain a light emitting device with a long operating life. In order to achieve this, one of the compounds forming the exciplex must be a metal element with a large spin-orbit coupling. Specifically, transition metal elements are preferred, and platinum group elements (ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium ( It is preferable to have iridium (Ir) or platinum (Pt) This can promote intersystem crossing between the singlet and triplet excited states of the exciplex. Very desirable.

[0048] In the above configuration, it is necessary to use a material with a high luminescence quantum yield as the material for forming the exciplex. This makes material design easier and broadens the range of material choices. At least one of the compounds can convert triplet excitation energy into luminescence by itself. or platinum group elements (Ru, Rh, Pd, Os, Ir, or Pt) In the case where the compound has the formula (I), the luminescence quantum yield of the compound is 0% or more at room temperature or ordinary temperature. It may be between 0% and 40% or between 0% and 25%. It may be 0% or more and 10% or less, or even 0% or more and 1% or less. That's fine.

[0049] In addition, in a general light-emitting device of a host-guest system using a phosphorescent compound, it is difficult to obtain a desired emission color. On the other hand, it is difficult to obtain a light-emitting element that satisfies the above requirements and has high efficiency. Since exciplexes are used as luminescent materials, it is possible to achieve the desired luminescence color and increase efficiency. It becomes possible.

[0050] FIG. 2(A) is a cross-sectional view showing an example of the light-emitting layer 130 shown in FIG. The light-emitting layer 130 shown includes a compound 131 and a compound 132. In the following description, the compound 131 is preferably a phosphorescent compound. The structure using a phosphorescent compound as 131 will be explained. Any compound that does not emit light at room temperature may be used.

[0051] In addition, the compound 131 and the compound 132 contained in the light-emitting layer 130 form an exciplex. A combination is preferred.

[0052] The combination of Compound 131 and Compound 132 is a combination capable of forming an exciplex. However, one of them is a compound that has the function of transporting holes (hole transport property). and the other is a compound having a function of transporting electrons (electron transport property). In this case, it becomes easier to form donor-acceptor type exciplexes, and the exciplexes are efficiently formed. In addition, the combination of Compound 131 and Compound 132 can form a hole transport When a compound having electron transport properties is used in combination with a compound having electron transport properties, the mixing ratio This makes it possible to easily control the carrier balance. The compound having the property of electron transporting and the compound having the property of electron transporting are preferably in the range of 1:9 to 9:1 (weight ratio). Moreover, by having this configuration, it is possible to easily control the carrier balance. Therefore, the carrier recombination region can be easily controlled.

[0053] Compounds 131 and 132 that efficiently form exciplexes include Compound 1 The HOMO (Highest Occupied Mo) of either compound 31 or compound 132 The HOMO level of the other atom is higher than the HOMO level of the other atom. The other LUMO (Lowest Unoccupied Molecular It is preferable that the LUMO level of the other nucleus is higher than the LUMO level of the other nucleus. The HOMO level of compound 131 is equal to or greater than the HOMO level of compound 132. The LUMO level of compound 131 may be equivalent to the LUMO level of compound 132.

[0054] 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.

[0055] For example, when compound 131 has hole transport properties and compound 132 has electron transport properties, As shown in the energy band diagram in Figure 2(B), the HOMO level of compound 131 is The HOMO level of compound 131 is preferably higher than the HOMO level of compound 32, and the LUMO level of compound 131 is preferably higher than the HOMO level of compound 32. It is preferable that the LUMO level of the 2-atom compound is higher than that of the 2-atom compound. The electron holes and electrons are carriers injected from a pair of electrodes (electrodes 101 and 102). This is preferable because electrons are easily injected into compound 131 and compound 132, respectively.

[0056] In FIG. 2(B), Comp(131) represents compound 131, and Comp(1 32) represents compound 132, and ΔE C1 are the LUMO and HOMO levels of compound 131. represents the energy difference between the C2is the energy difference between the LUMO and HOMO levels of compound 132. represents the energy difference, and ΔE Ex is the LUMO level of compound 132 and the HOMO level of compound 131. The notation and symbol represent the energy difference between

[0057] In addition, the exciplex formed by Compound 131 and Compound 132 has a HOMO and compound 132 has the LUMO molecular orbital, forming an exciplex. The excitation energy of the exciplex is determined by the LUMO level of compound 132 and the HOM level of compound 131. The energy difference between the O level (ΔE Ex ) and the LUMO level of compound 131 is The energy difference between the MO level (ΔE C1 ) and the LUMO and HOMO levels of compound 132 The energy difference (ΔE C2 ) is smaller than Compound 131 and Compound 13 By forming an exciplex with 2, it is possible to form an excited state at a lower excitation energy. Furthermore, because of the lower excitation energy, the exciplex is in a stable excited state. It is possible to form a state.

[0058] In addition, the correlation between the energy levels of the compound 131 and the compound 132 in the light-emitting layer 130 is This is shown in Figure 2(C). The notations and symbols in Figure 2(C) are as follows: ·Comp(131): Compound 131 (phosphorescent compound) ·Comp(132): Compound 132 ·S C1 : S1 level of compound 131 T C1 :T1 level of compound 131 ·S C2 : S1 level of compound 132 T C2 :T1 level of compound 132 ·S Ex : S1 level of the exciplex T Ex :T1 level of exciplex

[0059] In the light-emitting element of one embodiment of the present invention, the light-emitting layer 130 contains Compound 131 and Compound 1 32 forms an exciplex. The S1 level of the exciplex (S Ex ) and the T1 level of the exciplex (T Ex ) are adjacent energy levels (see route A1 in Figure 2(C)).

[0060] An exciplex is an excited state consisting of two types of substances, and its formation process involves the following two main steps: There is a process.

[0061] One is the process of forming an electroplex. In the literature, electroplex refers to the state in which carriers are injected and ionized (in a cation state). The interaction of compound 131 (in the di- or anionic state) with compound 132 results in an exciplex. The formation of electroplexes is caused by electrical excitation. In this embodiment, either Compound 131 or Compound 132 traps holes. The other accepts an electron, and the two interact to rapidly form an exciplex. This corresponds to the electroplex formation process. In this case, both Compound 131 and Compound 132 do not form an excited state by themselves. Therefore, each compound that forms an exciplex (compound 13) The excitation lifetime and luminescence quantum yield of 1 and compound 132 do not affect the exciplex formation process. That is, the amount of light emitted by each compound (compound 131 and compound 132) that forms the exciplex Even if the molecular yield is low, one embodiment of the present invention can efficiently form an exciplex. In the above process, the S1 level (S C1 ) is compound 13 S1 level of 2 (S C2 ) may be higher or lower than the T1 level of compound 131. (T C1 ) is the T1 level (T C2 ) may be higher or lower.

[0062] The other is that one compound that receives excitation energy and becomes excited is in the ground state. This is the process by which an exciplex is formed by interacting with another compound. The process of condensation is a phenomenon that can occur in photoexcitation and electrical excitation. Either compound 131 or compound 132 receives light or electrical energy and enters an excited state. The process by which one electron in the ground state rapidly interacts with the other electron in the ground state to form an exciplex is called This corresponds to the exciplex formation process described above. Even if the excited state of 1 is generated and the deactivation rate of the excited state is fast, the compound 131 T1 level (T C1 ) is the T1 level of compound 132 (T C2 ) or more, compound 131 T1 level (T C1 ) to the T1 level of compound 132 (T C2 ) excitation energy is transferred to In addition, the T1 level (T C1 ) to the T1 level of compound 132 ( T C2 After the excitation energy is transferred to compound 131, compound 132 forms an exciplex. Therefore, the deactivation rate of the excited state of compound 131 is fast, and the deactivation rate of compound 13 is fast. Even if the emission quantum yield of 1 is low, one embodiment of the present invention can efficiently form an exciplex. In the above process, the S1 level (S C1 )teeth The S1 level of compound 132 (S C2 ) may be higher or lower.

[0063] The exciplexes generated by the above process can lose their excitation energy by emitting light, etc. Therefore, when the exciplex returns to the ground state, the two substances that formed the exciplex return to their original separate states. Act as.

[0064] Excitation energy levels of exciplexes (S Ex and T Ex ) is the number of substances that form exciplexes. The S1 level (S C1 and S C2 ) lower than This allows the formation of excited states with lower excitation energy. The drive voltage of the optical element 150 can be reduced.

[0065] The S1 level of the exciplex (S Ex ) and T1 level (T Ex ) are adjacent energy levels Because the exciplex is a triplet excited state, it has the function of exhibiting thermally activated delayed fluorescence. The photon energy is converted to singlet excitation energy by reverse intersystem crossing (upconversion). Therefore, a part of the triplet excitation energy generated in the light-emitting layer 130 is converted to singlet excitation energy by the exciplex. Rank (S Ex ) and T1 level (T Ex ) is preferably greater than 0 eV and It is preferably 0.2 eV or less, more preferably more than 0 eV and 0.1 eV or less. To efficiently generate the difference, the T1 level (T Ex ) forms an exciplex The T1 level (T C1 and T C2 ) than This allows the triplet of exciplexes formed by Compound 131 and Compound 132 to be formed. The triplet excitation energy is less likely to be quenched, and the exciplex efficiently converts the triplet excitation energy. Reverse intersystem crossing from the ionized energy to the singlet excitation energy, and the subsequent It is possible to obtain light emission from the

[0066] In one embodiment of the present invention, one of the compounds forming the exciplex has a heavy atom. The compound promotes intersystem crossing between the singlet and triplet states. , it is possible to form an exciplex that exhibits luminescence (phosphorescence) from triplet excitation energy. In addition, the S1 level of the exciplex (S Ex ) and T1 level (T Ex ) are adjacent energy -level, it is difficult to clearly distinguish between fluorescence and phosphorescence in the emission spectrum. In such cases, it may be possible to distinguish between fluorescence and phosphorescence by the emission lifetime. There is a match.

[0067] In order to allow the above electroplex formation process to occur predominantly, for example, Compound 1 When compound 31 has hole transport properties and compound 132 has electron transport properties, the HO of compound 131 The MO level of compound 131 is preferably higher than the HOMO level of compound 132. It is preferable that the O level is higher than the LUMO level of compound 132. Specifically, The energy difference between the HOMO level of compound 1 and the HOMO level of compound 132 is preferably 0.1 eV or more, more preferably 0.2 eV or more, and even more preferably 0.3 eV or more. In addition, the energy difference between the LUMO level of compound 131 and the LUMO level of compound 132 is The energy difference is preferably 0.1 eV or more, more preferably 0.2 eV or more, and The energy difference is more preferably 0.3 eV or more. The holes and electrons, which are carriers injected from the electrodes 101 and 102, are transferred to the compound 13. Compound 1 and Compound 132 are suitable for easy injection.

[0068] Note that Compound 131 has an electron transporting property, and Compound 132 has a hole transporting property. In that case, as shown in the energy band diagram of FIG. 4(A), The HOMO level of compound 132 is preferably higher than that of compound 131. Preferably, the UMO level is higher than the LUMO level of compound 131.

[0069] In addition, the weight ratio of Compound 131 to Compound 132 is low. Preferably, the weight ratio of compound 131 to compound 132 is preferably 0.0 The range is 1 or more and 0.5 or less, and more preferably 0.05 or more and 0.3 or less. By setting the weight ratio within this range, the electron transport is promoted by the direct recombination process of carriers in one compound. This is preferred as it allows the cycloplex formation process to dominate.

[0070] <Light-emitting mechanism of light-emitting elements 2> Next, a configuration example different from that of the light-emitting layer shown in FIG. 2(A) will be explained below with reference to FIG. 3(A). Make it clear.

[0071] FIG. 3(A) is a cross-sectional view showing an example of the light-emitting layer 130 shown in FIG. The light-emitting layer 130 shown has compounds 131, 132, and 133.

[0072] In the light-emitting layer 130, compound 132 or compound 133 is present in the largest amount by weight. Compound 131 is dispersed in Compound 132 and Compound 133. The compound is preferably a phosphorescent compound, but any compound containing a platinum group element will emit light at room temperature. Compounds 131 and 132 may be compounds that do not exhibit an exciplex. It is preferable that the combination is such that

[0073] In addition, as a combination of compounds that efficiently form exciplexes, Compound 131 and Compound 132 are The HOMO level of one of the compounds 132 is higher than the highest HOMO level of the material in the light-emitting layer 130. the other LUMO level is the lowest LUMO level of the material in the light-emitting layer 130. That is, it is preferable that the HOMO level of one of Compound 131 and Compound 132 is higher than that of the other. The HOMO level of one compound is higher than that of compound 133, and the LUMO level of the other compound is the same. It is preferable that the LUMO level of the compound 133 is lower than that of the compound 133. By establishing a suitable energy level correlation, compound 132 and compound 133 form an exciplex. This can suppress the reaction.

[0074] For example, when compound 131 has hole transport properties and compound 132 has electron transport properties, As shown in the energy band diagram in Figure 3(B), the HOMO level of compound 131 is The HOMO level of the compound 32 is preferably higher than the HOMO level of the compound 133. The LUMO level of compound 132 is the same as that of compound 131 and that of compound 133. The LUMO level of compound 133 is preferably lower than that of compound 131. The HOMO level of compound 133 may be higher or lower than the O level of compound 132. The HOMO level may be higher or lower than that of the

[0075] In FIG. 3(B), Comp(131) represents compound 131, and Comp(1 32) represents compound 132, Comp(133) represents compound 133, and ΔE C1 transformation represents the energy difference between the LUMO level and the HOMO level of compound 131, and ΔE C2 is compound 1 represents the energy difference between the LUMO level and the HOMO level of 32, and ΔE C3 is compound 133 represents the energy difference between the LUMO level and the HOMO level, and ΔE Ex is the LUM of compound 132 The notation and symbol represent the energy difference between the O level and the HOMO level of compound 131.

[0076] The excitation energy of the exciplex formed by Compound 131 and Compound 132 is The energy difference (ΔE Ex ) The energy difference between the LUMO level and the HOMO level of compound 133 (ΔE C3 )Yo It is preferable that the value is smaller than 1 / 2.

[0077] Compound 131, Compound 132, and Compound 13 in the light-emitting layer 130 shown in FIG. The correlation of the energy levels with 3 is shown in Figure 3(C). The numbers are as follows: ·Comp(131): Compound 131 (phosphorescent compound) ·Comp(132): Compound 132 ·Comp(133): Compound 133 ·S C1 : S1 level of compound 131 T C1 :T1 level of compound 131 ·S C2 : S1 level of compound 132 T C2 :T1 level of compound 132 ·S C3 : S1 level of compound 133 T C3 :T1 level of compound 133 ·S Ex : S1 level of the exciplex T Ex :T1 level of exciplex

[0078] In the light-emitting element of one embodiment of the present invention, the light-emitting layer 130 contains Compound 131 and Compound 1 32 forms an exciplex. The S1 level of the exciplex (S Ex ) and the T1 level of the exciplex (T Ex ) are adjacent energy levels (see route A1 in Figure 3(C)).

[0079] T1 level of compound 133 (T C3 ) is the T1 level (T C1 ) or more In addition, the T1 level (T C1 ) is compound 131 and compound 132 The T1 level (T Ex ) or more. By assuming a correlation between the excited states of the exciplex formed by compound 131 and compound 132, The triplet excitation energy is efficiently released by the exciplex. Emission from the triplet excitation energy, or reverse intersystem crossing from the triplet excitation energy to the singlet excitation energy, This makes it possible to obtain the emission from the singlet excitation energy.

[0080] In order to favor the electroplex formation process, The light-emitting layer 130 contains the compound 131 and It is preferable to add a material other than Compound 132 to the light-emitting layer 130. By using compound 133 in addition to compound 31 and compound 132, compound 131 and compound 13 2 can easily form an electroplex. The weight ratio of the total amount of compound 133 to compound 131 is preferably low. Preferably, specifically, the weight ratio of Compound 131 to the total amount of Compound 132 and Compound 133 is preferably 0.01 or more and 0.5 or less, and more preferably 0.05 or more and 0.3 or less. is.

[0081] Note that Compound 131 has an electron transporting property, and Compound 132 has a hole transporting property. In that case, as shown in the energy band diagram of FIG. 4(B), The HOMO level is higher than that of compound 131 and that of compound 133. It is preferable that the LUMO level of compound 131 is higher than the LUMO level of compound 132. The LUMO level of compound 133 is preferably lower than that of compound 133. The LUMO level of compound 132 may be higher or lower than that of compound 132. The O level can be either higher or lower than the HOMO level of compound 131.

[0082] <Material> Next, components of a light-emitting element according to one embodiment of the present invention will be described in detail below.

[0083] <Light-emitting layer> The materials that can be used for the light-emitting layer 130 are described below.

[0084] Compound 131 and Compound 132 are a combination that form an exciplex with each other. There is no particular limitation as long as one has a function of transporting electrons and the other has a function of transporting holes. It is preferable that the

[0085] When compound 132 has a hole transport function, compound 132 is a π-electron-rich heteroaromatic It is preferable that the compound has at least one of an aromatic skeleton and an aromatic amine skeleton.

[0086] The π-electron-rich heteroaromatic skeleton of compound 132 is a furan skeleton, a thiophene skeleton, Since the skeleton and pyrrole skeleton are stable and reliable, any one selected from these skeletons can be used. It is preferable that the furan skeleton has one or more of the following. As the thiophene skeleton, a dibenzothiophene skeleton is preferred. The rol skeleton includes an indole skeleton, a carbazole skeleton, and a 3-(9-phenyl-9 The preferred skeleton is a 9H-carbazole skeleton. The case may have a substituent.

[0087] The aromatic amine skeleton of compound 132 does not have an NH bond, so-called Tertiary amines are preferred, and triarylamine skeletons are particularly preferred. The aryl group is a substituted or unsubstituted aryl group having 6 to 13 carbon atoms in the ring. Preferred are groups, such as a phenyl group, a naphthyl group, and a fluorenyl group.

[0088] 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, Examples of such structures include those having a methylamine skeleton.

[0089] Examples of the π-electron-rich heteroaromatic skeleton and aromatic amine skeleton include the following: Examples of the skeletons are those represented by the general formulae (101) to (117). X in (117) represents an oxygen atom or a sulfur atom.

[0090] [ka]

[0091] Alternatively, when compound 132 has the function of transporting electrons, compound 132 is π-electron deficient. The π-electron deficient heteroaromatic skeleton is preferably a pyridine. skeleton, diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), and triazine Among them, a diazine skeleton or a triazine skeleton is preferred because it is stable and has good reliability. This is preferable.

[0092] Examples of the π-electron deficient heteroaromatic skeleton include those represented by the following general formulas (201) to (2 18). In addition, X in the general formulae (209) to (211) is Represents an oxygen atom or a sulfur atom.

[0093] [ka]

[0094] In addition, a skeleton having hole transport properties (specifically, a π-electron-rich heteroaromatic skeleton and an aromatic amine skeleton) and a skeleton having electron transport properties (specifically, a π-electron deficient complex A compound in which the aromatic skeleton 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 diyl group and a fluorenediyl group.

[0095] As a linking group that links the skeleton having hole transport properties and the skeleton having electron transport properties, Examples of the group include groups represented by the following general formulas (301) to (315).

[0096] [ka]

[0097] The aromatic amine skeleton (specifically, for example, a triarylamine skeleton), π-electron excess heteroaromatic skeleton (specifically, for example, a furan skeleton, a thiophene skeleton, a pyrrole skeleton) 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 formulas (101) to (117), general formula (201) The general formulae (218) and (301) to (315) may have a substituent. The substituents include alkyl groups having 1 to 6 carbon atoms, cycloalkyl groups having 3 to 6 carbon atoms, and alkyl groups having 1 to 6 carbon atoms. alkyl groups, or substituted or unsubstituted aryl groups having 6 to 12 carbon atoms; Specific examples of alkyl groups 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 cyclopropyl group, and a cyclopropyl group. butyl group, cyclopentyl group, cyclohexyl group, etc. Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, and the like. Specific examples include a methyl group and a methyl group. In addition, the above substituents may be bonded to each other to form a ring. Such an example may include a fluorene group in which the carbon at the 9-position is substituted. When the compound has two phenyl groups as a group, the phenyl groups are bonded to each other to form a s In the case of unsubstituted fluorene, the synthesis is easy. It is advantageous in terms of ease of production and the cost of raw materials.

[0098] In addition, Ar represents a single bond or an arylene group having 6 to 13 carbon atoms, The olefin 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 compound in which the carbon atom at the 9th position of the fluorenyl group has a phenyl group as a substituent. The two phenyl groups bond together to form a spirofluorene skeleton. Examples of the arylene group having 6 to 13 carbon atoms include: 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 substituted aryl group or an aryl group having 6 to 12 carbon atoms can also be selected. 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-butyl group and cycloalkyl groups having 3 to 6 carbon atoms. Specific examples of the alkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl ... and cyclohexyl groups. Also, aryl groups having 6 to 12 carbon atoms are examples. Specific examples of the alkyl group include a phenyl group, a naphthyl group, and a biphenyl group. This can be done.

[0099] The arylene group represented by Ar is, for example, the following structural formula (Ar-1) to (Ar- 18) can be applied. The groups that can be used as Ar are This is not limited to these.

[0100] [ka]

[0101] Also, R 1 and R 2 are each independently 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 alkyl groups 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 ... 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 include a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. Examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a naphthyl group, Specific examples include a biphenyl group and a fluorenyl group. The aryl group and phenyl group may have a substituent, and the substituents may be bonded to each other to form a ring. The substituent may be an alkyl group having 1 to 6 carbon atoms, 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 or aryl groups having 6 to 12 carbon atoms are also substituents. Specific examples of alkyl groups having 1 to 6 carbon atoms include: For example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t Examples of the alkyl group include an n-butyl group and an n-hexyl group. Specific examples of the cycloalkyl group having six carbon atoms include a cyclopropyl group and a cyclobutyl group. Examples of the cyclohexyl group include cyclopentyl groups, cyclohexyl groups, and cyclopentyl groups. Examples of the aryl group having up to 12 carbon atoms include a phenyl group, a naphthyl group, and a biphenyl group. Examples of specific examples include:

[0102] 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.

[0103] [ka]

[0104] In addition, general formulas (101) to (117), general formulas (201) to (218), and general formula ( 301) to (315), and Ar, R 1 and R 2 The substituents that 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 suitably used. The alkyl group or aryl group can be selected from the group consisting of: This is not limited to these.

[0105] As the compound 132, for example, the following hole transporting material and electron transporting material can be used: This can be done.

[0106] As the hole transporting material, a material having a higher hole transporting property than an electron transporting property can be used. x10 -6 cm 2 It is preferable that the material has a hole mobility of 1 / Vs or more. Aromatic amines, carbazole derivatives, etc. can be used as the hole transporting material. The material may be a polymer compound.

[0107] As a material having high hole transporting properties, for example, aromatic amine compounds such as N,N' -Di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDP PA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino ]biphenyl (abbreviation: DPAB), N,N'-bis{4-[bis(3-methylphenyl) amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-di Amine (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl [N-phenylamino]benzene (abbreviation: DPA3B), and the like.

[0108] Specific examples of carbazole derivatives include 3-[N-(4-diphenylamino phenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA1 ), 3,6-bis[N-(4-diphenylaminophenyl)-N-phenylamino]-9 -phenylcarbazole (abbreviation: PCzDPA2), 3,6-bis[N-(4-diphenyl [N-(1-naphthyl)amino]-9-phenylcarbazole (abbreviation :PCzTPN2), 3-[N-(9-phenylcarbazol-3-yl)-N-phenyl 3,6-bis[N- (9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazol PCzPCA2, 3-[N-(1-naphthyl)-N-(9-phenylcarbazone] [carbazol-3-yl]amino]-9-phenylcarbazole (abbreviation: PCzPCN1) The following can be mentioned:

[0109] Other carbazole derivatives include 4,4'-di(N-carbazolyl)biphene. Nyl (abbreviation: CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzoyl Zene (abbreviation: TCPB), 1,4-bis[4-(N-carbazolyl)phenyl]-2,3 , 5,6-tetraphenylbenzene, etc. can be used.

[0110] Furthermore, examples of materials with high hole transport properties include 4,4'-bis[N-(1-naphthyl )-N-phenylamino]biphenyl (abbreviation: NPB or α-NPD) and N,N'-biphenyl (3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4 '-diamine (abbreviation: TPD), 4,4',4''-tris(carbazol-9-yl) Triphenylamine (abbreviation: TCTA), 4,4',4''-tris[N-(1-naphthyl) 1-TNATA, 4,4'-N-phenylamino]triphenylamine 4''-Tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA) , 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino]tri Phenylamine (abbreviation: m-MTDATA), 4,4'-bis[N-(spiro-9,9' -bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4 -phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenyl Nylamine (abbreviation: mBPAFLP), N-(9,9-dimethyl-9H-fluorene-2 -yl)-N-{9,9-dimethyl-2-[N'-phenyl-N'-(9,9-dimethyl -9H-fluoren-2-yl)amino]-9H-fluoren-7-yl}phenylamino N-(9,9-dimethyl-2-diphenylamino-9H- Fluoren-7-yl)diphenylamine (abbreviation: DPNF), 2-[N-(4-diphenyl) N-phenylaminophenyl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: DPASF), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl) Triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9- Phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1B) P), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl) Triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''- (9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCBN BB), 4-phenyldiphenyl-(9-phenyl-9H-carbazol-3-yl)a amine (abbreviation: PCA1BP), N,N'-bis(9-phenylcarbazol-3-yl) -N,N'-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N,N', N''-triphenyl-N,N',N''-tris(9-phenylcarbazole-3-yl) N-(4-biphenyl)benzene-1,3,5-triamine (abbreviation: PCA3B) -N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-chlor PCBiF, N-(1,1'-biphenyl-4-yl) -N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-di Methyl-9H-fluoren-2-amine (abbreviation: PCBBiF), 9,9-dimethyl-N -phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl] Fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl -9H-carbazol-3-yl)phenyl]spiro-9,9'-bifluorene-2-a PCBASF, 2-[N-(9-phenylcarbazol-3-yl)-N -phenylamino]spiro-9,9'-bifluorene (abbreviation: PCASF), 2,7-bi Spiro-9,9'-[N-(4-diphenylaminophenyl)-N-phenylamino]spiro Bifluorene (abbreviation: DPA2SF), N-[4-(9H-carbazol-9-yl)fluorene] N,N'-phenyl]-N-(4-phenyl)phenylaniline (abbreviation: YGA1BP), Bis[4-(carbazol-9-yl)phenyl]-N,N'-diphenyl-9,9-di Aromatic amine compounds such as methylfluorene-2,7-diamine (abbreviation: YGA2F) Also, 3-[4-(1-naphthyl)-phenyl]-9-phenyl can be used. -9H-carbazole (abbreviation: PCPN), 3-[4-(9-phenanthryl)-phenyl 3,3'-bis(9- phenyl-9H-carbazole) (abbreviation: PCCP), 1,3-bis(N-carbazolyl ) benzene (abbreviation: mCP), 3,6-bis(3,5-diphenylphenyl)-9-phenyl CzTP, 4-[3-[3-(9-phenyl-9H-fluorophenyl) (9-phenyl)phenyl)dibenzofuran (abbreviation: mmDBFFLBi-I I), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), 1,3,5-tri(dibenzothiophen-4-yl)benzoate DBT3P-II, 2,8-diphenyl-4-[4-(9-phenyl-9 H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-II I), 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyl Nyldibenzothiophene (abbreviation: DBTFLP-IV), 4-[3-(triphenylene- Amination of [2-yl]phenyldibenzothiophene (abbreviation: mDBTPTp-II) etc. compounds, carbazole compounds, thiophene compounds, furan compounds, fluorene compounds, tri Phenylene compounds, phenanthrene compounds, etc. can be used. , mainly 1×10 -6 cm 2 / Vs or more. Any other substance may be used as long as it has a high hole transporting property.

[0111] As the electron transporting material, a material having a higher electron transporting property than a hole transporting property can be used. x10 -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 containing zinc or aluminum. using π-electron-deficient heteroaromatic compounds such as metal complexes and nitrogen-containing heteroaromatic compounds. The metal complexes include quinoline ligands, benzoquinoline ligands, oxazoline ligands, and the like. Metal complexes having thiazole or thiazole ligands are also known. Heteroaromatic compounds include oxadiazole derivatives, triazole derivatives, phenanthrene derivatives, and the like. Loline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, triazine derivatives Examples include the body.

[0112] For example, tris(8-quinolinolato)aluminum(III) (abbreviation: Alq), tri Bis(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq3), Bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq2 ), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum ( III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq) These include metal complexes having a quinoline skeleton or a benzoquinoline skeleton. Bis[2-(2-benzoxazolyl)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-(dibenzothiazolinone) [4-(4-phenyl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: m DBTBIm-II), bathophenanthroline (abbreviated as BPhen), bathocuproine (abbreviation: BCP), 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1, Heterocyclic compounds such as 10-phenanthroline (abbreviated as NBPhen) and 2-[3-(diphenyl ether) benzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2m DBTPDBq-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: 2Cz PDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo [f,h]quinoxaline (abbreviation: 7mDBTPDBq-II) and 6-[3-(dibenzyl) (benzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mD BTPDBq-II), 4,6-bis[3-(phenanthrene-9-yl)phenyl]pi Rimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl )phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3- (9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm ) and heterocyclic compounds with a diazine skeleton, such as 2-{4-[3-(N-phenyl-9H -carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-di Triazine skeleton such as phenyl-1,3,5-triazine (abbreviation: PCCzPTzn) Heterocyclic compounds having 3,5-bis[3-(9H-carbazol-9-yl)phenyl] ]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridyl)phenyl Heterocyclic compounds with a pyridine skeleton, such as 4, 4'-Bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs) Heteroaromatic compounds such as poly(2,5-pyridinediyl) (abbreviation: PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co- (pyridine-3,5-diyl)] (abbreviation: PF-Py), poly[(9,9-dioctyl fluoride) fluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)]( Polymer compounds such as PF-BPy can also be used. , mainly 1×10 -6 cm 2 It is a material with electron mobility of 1 / Vs or more. Any substance other than those mentioned above may be used as long as it has a high electron transporting property.

[0113] Compound 131 (phosphorescent compound) is an iridium, rhodium, or platinum-based compound. Organometallic complexes or metal complexes of porphyrin ligands are also available. Gold complexes and organic iridium complexes are mentioned, among which iridium orthometal complexes are mentioned. Preferred are organic iridium complexes such as 4H-triazolium as the orthometalating ligand. 1H-triazole ligands, 1H-triazole ligands, imidazole ligands, pyridine ligands, pyrimidine ligands Examples of the ligand include an azine ligand, a pyrazine ligand, and an isoquinoline ligand. , Compound 131 (phosphorescent compound) is triplet MLCT (Metal to Ligand It has an absorption band for the charge transfer transition.

[0114] 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-κN 2 ]phenyl-κC}iridium(III) (abbreviation: Ir(mpp tz-dmp)3), tris(5-methyl-3,4-diphenyl-4H-1,2,4-trimethyl- Triazolato)iridium(III) (abbreviation: Ir(Mptz)3), tris[4-(3- Biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]i Iridium(III) (abbreviation: Ir(iPrptz-3b)3), tris[3-(5-biphenyl] (phenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]irid Ir(III) (abbreviated as Ir(iPr5btz)3), a 4H-triazole skeleton and organometallic iridium complexes with tris[3-methyl-1-(2-methylphenyl) -5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: Ir (Mptz1-mp)3), tris(1-methyl-5-phenyl-3-propyl-1H- 1,2,4-Triazolate)iridium(III) (abbreviation: Ir(Prtz1-Me) 3) and other organometallic iridium complexes with a 1H-triazole skeleton, such as fac-triazole. S[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]isopropyl Iridium(III) (abbreviation: Ir(iPrpmi)3), tris[3-(2,6-dimethyl phenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(I II) Imidazole skeleton-containing compounds such as Ir(dmpimpt-Me) Organic metal iridium complexes and bis[2-(4',6'-difluorophenyl)pyridinato- N,C 2’ ]iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation: FI r6), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ]Ili Dium(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis (Trifluoromethyl)phenyl]pyridinato-N,C 2’}Iridium(III) pico Ir(CF3ppy)2(pic) (fluorophenyl)pyridinato-N,C 2’ ]Iridium(III) acetylacetonate (abbreviation: FIr(acac)) Among the above, 4H-triazole is an organometallic iridium complex. a nitrogen-containing five-membered heterocyclic skeleton such as a 1H-triazole skeleton and an imidazole skeleton; The organometallic iridium complexes have high triplet excitation energy and are highly reliable and highly efficient. It is particularly preferred because it is also excellent in

[0115] Furthermore, examples of substances having a green or yellow emission peak include tris(4-methylphenyl) Ir(mppm)3, Tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: I r(tBuppm)3), (acetylacetonato)bis(6-methyl-4-phenylpyridine) Iridium(III) (abbreviation: Ir(mppm)2(acac)), (acetylacetonate ruacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium( III) (Abbreviation: Ir(tBuppm)2(acac)), (acetylacetonato)bis [4-(2-norbornyl)-6-phenylpyrimidinato]iridium(III) do-, exo-mixture) (abbreviation: Ir(nbppm)2(acac)), (acetylacetone cetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato ]Iridium(III) (abbreviation: Ir(mpmppm)2(acac)), (acetylacetone cetonato)bis{4,6-dimethyl-2-[6-(2,6-dimethylphenyl)-4-pi Rimidinyl-κN 3]phenyl-κC}iridium(III) (abbreviation: Ir(dmppm -dmp)2(acac)), (acetylacetonato)bis(4,6-diphenylpyrimidine) pyridinium(III) (abbreviation: Ir(dppm)2(acac)) Organometallic iridium complexes with a methylamine skeleton and (acetylacetonato)bis(3,5- Dimethyl-2-phenylpyrazinato)iridium(III) (abbreviation: Ir(mppr-M e) 2(acac)), (acetylacetonato)bis(5-isopropyl-3-methyl- 2-phenylpyrazinato)iridium(III) (abbreviation: Ir(mppr-iPr)2( Organometallic iridium complexes with pyrazine skeletons such as tris(2-fluoro-2-phenyl-1,2-diphenyl ... Phenylpyridinato-N,C 2’ ) Iridium(III) (abbreviation: Ir(ppy)3), Su(2-phenylpyridinato-N,C 2’ ) Iridium(III) acetylacetonate (Abbreviation: Ir(ppy)2(acac)), bis(benzo[h]quinolinato)iridium (III) Acetylacetonate (abbreviation: Ir(bzq)2(acac)), tris(benzyl) Tris(2-benzo[h]quinolinato)iridium(III) (abbreviation: Ir(bzq)3) -phenylquinolinato-N,C 2’ ) Iridium(III) (abbreviation: Ir(pq)3), Bis(2-phenylquinolinato-N,C) 2’ ) Iridium(III) acetylacetoner Organometallic iridates with pyridine skeletons, such as Ir(pq)2(acac) complexes and bis(2,4-diphenyl-1,3-oxazolato-N,C 2’ ) Irijiu Ir(III) acetylacetonate (abbreviation: 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-phenylbenzothiazolato-N,C 2’ ) Iridium(III) acetylacetonate In addition to organometallic iridium complexes such as tris( Acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: Tb(a cac)3(Phen)) are rare earth metal complexes. Organometallic iridium complexes with an iridium skeleton are highly reliable and highly efficient. Therefore, it is particularly preferable.

[0116] Furthermore, examples of substances having a yellow or red emission peak include (diisobutyryl) Methanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(II I) (abbreviation: Ir(5mdppm)2(dibm)), bis[4,6-bis(3-methyl [phenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: Ir (5mdppm)2(dpm)), bis[4,6-di(naphthalen-1-yl)pyrimidinyl] Nato](dipivaloylmethanato)iridium(III) (abbreviation: Ir(d1npm)2( Organometallic iridium complexes with pyrimidine skeletons, such as (acetylacetonyl acetone) Iridium(III) (abbreviation: I r(tppr)2(acac)), bis(2,3,5-triphenylpyrazinate)(dipyr Valoylmethanato)iridium(III) (abbreviation: Ir(tppr)2(dpm)), ( Acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]i Ir(Fdpq)2(acac) and other pyrazine-based compounds Organometallic iridium complexes and tris(1-phenylisoquinolinato-N,C 2’ ) Iridium(III) (abbreviation: Ir(piq)3), bis(1-phenylisoquinolinato) -N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(piq)2( In addition to organometallic iridium complexes with pyridine skeletons such as acac), 2,3,7, 8,12,13,17,18-Octaethyl-21H,23H-porphyrin platinum(II) ) (abbreviation: PtOEP) and tris(1,3-diphenyl-1,3-propanediol). Eu(DB)(propanedionato)(monophenanthroline)europium(III) M)3(Phen)), tris[1-(2-thenoyl)-3,3,3-trifluoroacetate [Tonato](monophenanthroline)europium(III) (abbreviation: Eu(TTA)3( Among the above, rare earth metal complexes such as pyrimidine skeletons are Organometallic iridium complexes having the above structure are particularly preferred because they are remarkably excellent in reliability and luminous efficiency. In addition, organometallic iridium complexes with a pyrazine skeleton can emit red light with good chromaticity. can be done.

[0117] In the light-emitting layer 130, the compound 133 can be made of, for example, Although not limited thereto, for example, tris(8-quinolinolato)aluminum(III) (abbreviation: A lq), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Al mq3), bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation :BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)a Aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation :ZnPBO), bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation ZnBTZ), 2-(4-biphenylyl)-5-(4-tert-butyl) phenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-( p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 3-(4-biphenylyl)-4-phenyl-5-(4-tert -butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 2,2',2''- (1,3,5-benzenetriyl)-tris(1-phenyl-1H-benzimidazole) ) (abbreviation: TPBI), bathophenanthroline (abbreviation: BPhen), bathocuproine (abbreviation: BCP), 9-[4-(5-phenyl-1,3,4-oxadiazole-2-yl] heterocyclic compounds such as 4,4'-phenyl]-9H-carbazole (abbreviation: CO11), -Bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as NPB or α-NPD), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1, 1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4'-bis[N-(s pyrro-9,9'-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: Aromatic amine compounds such as BSPB are also included. Anthrene derivatives, pyrene derivatives, chrysene derivatives, dibenzo[g,p]chrysene derivatives, etc. Specifically, 9,10-diphenylanthracene ( Abbreviation: DPAnth), N,N-diphenyl-9-[4-(10-phenyl-9-anth 4-(1-(4 ... 0-phenyl-9-anthryl)triphenylamine (abbreviation: DPhPA), 4-(9H -carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenyl Amine (abbreviation: YGAPA), N,9-diphenyl-N-[4-(10-phenyl-9- anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), N, 9-Diphenyl-N-{4-[4-(10-phenyl-9-anthryl)phenyl]phenyl 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-(10 -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'-(stilbe 9,9'-(stilbene-3,3'-diyl)diphenanthrene (abbreviation: DPNS), -4,4'-diyl)diphenanthrene (abbreviation: DPNS2), 1,3,5-tri(1- pyrenylbenzene (abbreviation: TPB3), etc. Among known materials, there are those with an energy gap larger than that of compound 131. One or more substances having a group may be selected and used.

[0118] The light-emitting layer 130 may be composed of two or more layers. When the light-emitting layer 130 is formed by laminating the first light-emitting layer and the second light-emitting layer in this order from the hole transport layer side, a substance having hole transport properties is used as a host material for the first light-emitting layer, and a substance having hole transport properties is used as a host material for the second light-emitting layer For example, a substance having an electron transport property is used as the light emitting element.

[0119] In the light-emitting layer 130, compounds other than the compounds 131, 132, and 133 are It may also have a material.

[0120] <Pair of electrodes> The electrode 101 and the electrode 102 have the function of injecting holes and electrons into the light-emitting layer 130. The electrodes 101 and 102 are made of metals, alloys, conductive compounds, and mixtures or laminates thereof. It can be formed using aluminum (Al) as a typical example of a metal. , and other transition metals such as silver (Ag), tungsten, chromium, molybdenum, copper, and titanium. , alkali metals such as lithium (Li) and cesium, 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 (ITSO), indium zinc oxide (Indium Zinc Oxide) inc Oxide), tungsten and zinc-containing indium oxide, etc. As the conductive compound, an inorganic carbon material such as graphene may be used. As described above, electrodes 101 and 102 are formed by stacking multiple layers of these materials. 2 or both may be formed.

[0121] 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. Conductive materials that have the function of transmitting light include those that transmit visible light. The transmittance is 40% or more and 100% or less, preferably 60% or more and 100% or less, and the resistance Resistivity is 1×10 -2 Electrically conductive materials with a conductivity of Ω·cm or less are also used. The electrode is made of a conductive material that has the function of transmitting and reflecting light. The conductive material has a visible light reflectance of 20% or more and 80% or less, preferably 4 0% or more and 70% or less, and the 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 (for example, 1 nm to 10 nm) that allows visible light to pass through. Either or both of the electrode 101 and the electrode 102 may be formed.

[0122] In this specification and the like, the electrode having the function of transmitting light includes an electrode having the function of transmitting visible light. It is sufficient to use a material that has both functionality and conductivity, such as the above-mentioned ITO. 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 containing 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.

[0123] 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.

[0124] <Hole injection layer> The hole injection layer 111 is formed by injecting holes from one of the pair of electrodes (electrode 101 or electrode 102). It has the function of promoting hole injection by reducing the injection barrier, and is used in materials such as transition metal oxides and fluorine. It is formed by phthalocyanine derivatives or aromatic amines. Examples include molybdenum oxide, vanadium oxide, ruthenium oxide, and tungsten oxide. , manganese oxide, etc. Phthalocyanine derivatives include phthalocyanine, Examples of aromatic amines include benzidine derivatives and phenyl Diamine derivatives, etc. Polymer compounds such as polythiophene and polyaniline Materials such as self-doped polythiophenes, poly(ethylenediamines), can also be used. Typical examples include poly(oxythiophene) / poly(styrenesulfonic acid).

[0125] The hole injection layer 111 is made of a compound material including a hole transporting material and a material that exhibits electron accepting properties. Alternatively, a layer containing a material exhibiting electron accepting properties and a layer containing a material exhibiting electron accepting properties may be used. A stack of layers containing hole transport materials may also be used. It is possible to exchange charges in the presence of a magnetic field. Materials that exhibit electron-accepting properties include quinodimethane. Organic acceptors such as benzophenone derivatives, chloranil derivatives, and hexaazatriphenylene derivatives Specifically, 7,7,8,8-tetracyano-2,3,5,6- Tetrafluoroquinodimethane (abbreviation: F4-TCNQ), chloranil, 2,3,6,7, 10,11-Hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation These compounds have electron-withdrawing groups (halogen groups or cyano groups), such as hydroxybenzoates (HAT-CN). In addition, transition metal oxides, for example, oxides of metals from Groups 4 to 8, can be used. In general, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, These include tungsten oxide, manganese oxide, and rhenium oxide. Among these, it is preferred because it is stable, has low hygroscopicity, and is easy to handle.

[0126] As the hole transporting material, a material having a higher hole transporting property than an electron transporting property can be used. x10 -6 cm 2 It is preferable that the material has a hole mobility of 1 / Vs or more. The aromatic amines and amines 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.

[0127] Examples of aromatic hydrocarbons include 2-tert-butyl-9,10-di(2-naphthyl) 2-tert-butyl-9,10-di(1-methyl-2-methyl-1,3-diphenyl ... -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 anthracene, 2,3,6,7-tetramethyl-9,10-di(2-naphthyl) 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-Tetracene (tert-butyl)perylene, etc. In addition, pentacene, coronene, etc. can also be used. In this way, 1×10 -6 cm 2 / Vs or more It is more preferable to use an aromatic hydrocarbon having 14 to 42 carbon atoms.

[0128] 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.

[0129] In addition, poly(N-vinylcarbazole) (abbreviation: PVK) and poly(4-vinyltriphenyl ether) Nylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenyl amino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide]( abbreviation: PTPDMA), poly[N,N'-bis(4-butylphenyl)-N,N'-bis Polymer compounds such as [(phenyl)benzidine] (abbreviation: Poly-TPD) can also be used. can.

[0130] <Hole transport layer> The hole transport layer 112 is a layer containing a hole transport material. The hole transport layer 112 is formed by injecting the hole into the hole injection layer 111. Since it has a function of transporting holes to the light-emitting layer 130, it has the same HOMO level as the hole injection layer 111. It is preferable that the HOMO level is the same as or close to the HOMO level.

[0131] The hole transport material may be any of the materials exemplified as the material for the hole injection layer 111. Also, 1×10 -6 cm 2 / Vs or more. 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 with a high hole transporting property may be not only a single layer but also a layer containing the above-mentioned substance. Two or more layers may be laminated.

[0132] ≪Electron transport layer≫ The electron transport layer 118 is connected to the other of the pair of electrodes (electrode 101 or electrode 102) via the electron injection layer 119. The electron transport material has the function of transporting electrons injected from the electrode 102 to the light-emitting layer 130. As the material, a material with higher electron transportability than holes can be used, and the -6 cm 2 It is preferable that the material has an electron mobility of 1 / Vs or more. As materials (materials with electron transport properties), π-electron deficient materials such as nitrogen-containing heteroaromatic compounds are Heteroaromatic compounds, metal complexes, etc. can be used. The quinoline ligand, benzoquinoline ligand, and the like mentioned above as electron transporting materials that can be used include Examples of the metal complex include a metal complex having an oxazole ligand or a metal complex having a thiazole ligand. Oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, pyridine derivatives compounds, bipyridine derivatives, pyrimidine derivatives, etc. -6 cm 2 It is preferable that the material has an electron mobility of 1 / Vs or more. Any substance other than those mentioned above may be used for the electron transport layer as long as it has 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.

[0133] 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. The layer for controlling the movement of electron carriers may be made of a material having high electron transport properties as described above. A small amount of material with high electron trapping properties is added to the layer, which suppresses the movement of electron carriers. This makes it possible to adjust the carrier balance. To prevent problems caused by electrons penetrating through the layer (such as a reduction in device lifespan) It has a great effect.

[0134] ≪Electron injection layer≫ The electron injection layer 119 promotes electron injection by reducing the electron injection barrier from the electrode 102. For example, Group 1 metals, Group 2 metals, or their oxides and halides In addition, the electron transport material and the corresponding electron transport material can be used. A composite material of a material exhibiting electron donating properties can also be used. Examples include Group 1 metals, Group 2 metals, and oxides thereof. are lithium fluoride (LiF), sodium fluoride (NaF), and cesium fluoride (CsF ), calcium fluoride (CaF2), lithium oxide (LiO x ) and other alkaline gold Metals, alkaline earth metals, or compounds thereof can be used. A rare earth metal compound such as erbium (ErF3) can be used. An electride may be used for 119. The electride may be, for example, calcium. Examples include a material in which electrons are added to a high concentration of a mixed oxide of aluminum and silicon. The injection layer 119 may be made of a material that can be used in the electron transport layer 118 .

[0135] The electron injection layer 119 may contain a composite material formed by mixing an organic compound and an electron donor. Such composite materials may be formed by electron donors giving electrons to organic compounds. In this case, the organic compound is It is preferable that the material is excellent in transporting the generated electrons. Specifically, for example, the above-mentioned The material constituting the electron transport layer 118 (metal complex, heteroaromatic compound, etc.) can be used. The electron donor may be any substance that exhibits electron donating properties to organic compounds. For the metal, alkali metals, alkaline earth metals and rare earth metals are preferred, and lithium, cesium, Examples include magnesium, calcium, erbium, and ytterbium. 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 (abbreviation: TTF). It can also be done as follows.

[0136] 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 contain other materials such as quantum dots. Inorganic compounds or polymeric compounds (oligomers, dendrimers, polymers, etc.) may be used. stomach.

[0137] Quantum dots include colloidal quantum dots, alloy quantum dots, and core-shell quantum dots. It is also possible to use quantum dots of the 2nd group and the 16th group, quantum dots of the 13th group, and the like. Contains element groups from group 15, 13 and 17, 11 and 17, or 14 and 15 Quantum dots may also be used. Alternatively, cadmium (Cd), selenium (Se), zinc (Zn ), sulfur (S), phosphorus (P), indium (In), tellurium (Te), lead (Pb), gallium Quantum dots containing elements such as Ga, As, and Al are used. It's fine.

[0138] Examples of liquid media used in wet processes include methyl ethyl ketone, cyclohexane, and the like. Ketones such as xanone, fatty acid esters such as ethyl acetate, halogens such as dichlorobenzene aromatic hydrocarbons, toluene, xylene, mesitylene, cyclohexylbenzene, etc. Hydrocarbons, aliphatic hydrocarbons such as cyclohexane, decalin, and dodecane, dimethylformamide Organic solvents such as dimethyl amide (DMF) and dimethyl sulfoxide (DMSO) can be used. Cut.

[0139] Furthermore, examples of polymer compounds that can be used in the light-emitting layer include poly[2-methacrylamide] and poly[2-methyl-2-propanol]. 5-(2-ethylhexyloxy)-1,4-phenylene vinylene] (abbreviation: MEH -PPV), polyphenylene such as poly(2,5-dioctyl-1,4-phenylene vinylene) Poly(9,9-di-n-octylfluorenyl-2,7-diol) -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. Furthermore, these polymer compounds, Poly(9-vinylcarbazole) (abbreviation: PVK), poly(2-vinylnaphthalene), poly Tri[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.

[0140] <Substrate> Furthermore, the light-emitting element according to one embodiment of the present invention may be formed on a substrate made of glass, plastic, or the like. As for the order of fabrication on the substrate, the layers may be stacked in order from the electrode 101 side. They may be stacked in order from the pole 102 side.

[0141] The substrate on which the light-emitting element according to one embodiment of the present invention can be formed is, for example, glass or quartz. Alternatively, a flexible substrate may be used. The substrate is a flexible substrate, such as polycarbonate. Examples of suitable substrates include plastic substrates made of polyacrylate and polyarylate. It is also possible to use a metal-deposited film. 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.

[0142] For example, in the present invention, a light emitting element can be formed using various substrates. The type of substrate is not particularly limited. An example of the substrate is a semiconductor substrate (e.g., a single crystal substrate or silicon substrate), SOI substrate, glass substrate, quartz substrate, plastic substrate, metal Substrate, stainless steel substrate, substrate with stainless steel foil, tungsten substrate, tungsten foil substrate, flexible substrate, laminated film, fibrous These include cellulose nanofibers (CNF), paper, and base films that contain these 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 (Polyterephthalate) and acrylic. Resins such as acrylic resins are also available. Examples include polypropylene, polyester, and Examples include polyvinyl fluoride, polyvinyl chloride, etc. Alternatively, examples include polyamide, Examples include polyimide, aramid, epoxy, inorganic vapor deposition film, and paper.

[0143] Alternatively, a flexible substrate may be used as the substrate, and the light emitting element may be formed directly on the flexible substrate. Alternatively, a release layer may be provided between the substrate and the light-emitting element. After a part or all of a device is completed, it is separated from the substrate and used to transfer it to another substrate. In this case, the light-emitting element can be transferred onto a substrate having poor heat resistance or a flexible substrate. The peeling layer may have a laminated structure of inorganic films, such as a tungsten film and a silicon oxide film. or a structure in which a resin film such as polyimide is formed on a substrate, etc., can be used.

[0144] That is, a light emitting element is formed using a certain substrate, and then the light emitting element is transferred to another substrate. The light emitting element may be disposed on another substrate. In addition to the substrates mentioned above, cellophane substrates, stone substrates, wood substrates, fabric substrates (natural fibers (silk, cotton, Hemp), synthetic fibers (nylon, polyurethane, polyester) or regenerated fibers (acetate (including cellulose, cupro, rayon, recycled polyester, etc.), leather substrate, rubber substrate, etc. By using these substrates, it is possible to produce light emitting elements that are durable and highly heat resistant. The light emitting element may be a small, lightweight, or thin light emitting element.

[0145] Furthermore, for example, a field effect transistor (FET) is formed on the above-mentioned substrate, and the FET and The light emitting element 150 may be fabricated on the electrically connected electrodes. In this way, an active matrix display device that controls the driving of light emitting elements can be manufactured.

[0146] As described above, the structure shown in this embodiment mode can be used in appropriate combination with other embodiment modes. Cut.

[0147] (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 explained below with reference to FIG. The parts with the same functions as those indicated by the symbols in 1 are given the same hatch pattern and the symbols are omitted. In addition, parts having similar functions are denoted by similar reference numerals, and their detailed explanations are omitted. may be omitted.

[0148] <Configuration example of light-emitting element> FIG. 5 is a schematic cross-sectional view of the light emitting element 250. As shown in FIG.

[0149] The light-emitting element 250 shown in FIG. 5 has a plurality of electrodes between a pair of electrodes (electrode 101 and electrode 102). 5, the light-emitting unit 106 and the light-emitting unit 108. 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 may also be true.

[0150] In addition, in the light-emitting element 250 shown in FIG. 5, the light-emitting unit 106 and the light-emitting unit 108 The light-emitting unit 106 and the light-emitting unit 108 are stacked 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 may have the same configuration but different 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.

[0151] The light emitting element 250 has a light emitting layer 130 and a light emitting layer 140. 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 layer The light-emitting unit 108 also includes a light-emitting layer 140. In addition to the above, a hole injection layer 116, a hole transport layer 117, an electron transport layer 118, and an electron injection layer 11 It has 9.

[0152] The charge generation layer 115 is formed by adding an acceptor material, which is an electron acceptor, to a hole transport material. Even if the electron transport material is an electron donor, a donor material may be added to the electron transport material. Alternatively, both of these structures may be stacked.

[0153] When the charge generation layer 115 contains a composite material of an organic compound and an acceptor substance, the The composite material that can be used for the hole-injection layer 111 shown in Embodiment 1 is used as the composite material. The organic compounds include aromatic amine compounds, carbazole compounds, aromatic carbonized compounds, and the like. Various compounds such as hydrogen and polymer compounds (oligomers, dendrimers, polymers, etc.) are used. As for the organic compound, a hole mobility of 1×10 -6 cm 2 / Vs However, it is preferable to use a substance that has 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 carrier transport properties, allowing for low voltage and low current operation. In addition, as in the light-emitting unit 108, the surface of the light-emitting unit on the anode side 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.

[0154] The charge generation layer 115 may be a layer containing a composite material of an organic compound and an acceptor substance, or another layer containing a compound of an organic compound and an acceptor substance. For example, the organic EL element may be formed as a laminated structure in which layers made of the organic EL element are combined. A layer including a composite material of a compound and an acceptor substance and a layer including a compound selected from electron donor substances. The compound may be formed by combining a layer containing the compound with a compound having a high electron transporting property. A layer containing a composite material of an organic compound and an acceptor substance and a layer containing a transparent conductive material are combined. It may also be formed by combining them.

[0155] The charge generating layer 115 sandwiched between the light emitting unit 106 and the light emitting unit 108 When a voltage is applied between the electrode 101 and the electrode 102, electrons are injected into one of the light-emitting units, It is sufficient if it injects holes into the other light-emitting unit. For example, in FIG. When a voltage is applied so that the potential of electrode 101 is higher than the potential of electrode 102, charge generation Layer 115 injects electrons into light-emitting unit 106 and holes into light-emitting unit 108. .

[0156] From the viewpoint of light extraction efficiency, the charge generation layer 115 is transparent to visible light (specifically, It is preferable that the charge generating layer 115 has a visible light transmittance of 40% or more. The charge generating layer 115 has a lower conductivity than the pair of electrodes (electrodes 101 and 102). If the conductivity of the charge generating layer 115 is as high as that of the pair of electrodes, the charge The carriers generated by the generating layer 115 flow in the direction of the film surface, and the electrode 101 and the electrode There are cases where light emission occurs in areas where there is no overlap with 102. To achieve this, the charge generation layer 115 is preferably formed of a material having a lower conductivity than the pair of electrodes. It's nice.

[0157] By forming the charge generating layer 115 using the above-mentioned materials, when a light emitting layer is laminated, In this case, the increase in the driving voltage can be suppressed.

[0158] In addition, although the light emitting element having two light emitting units has been described with reference to FIG. 5, the light emitting element having three light emitting units may be 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, high brightness light emission is possible while keeping the current density low, and furthermore, a long life is achieved. Furthermore, a light-emitting element with low power consumption can be realized.

[0159] At least one of the multiple units has the EL layer 100 shown in FIG. By applying the above structure, a light-emitting element with high luminous efficiency can be provided.

[0160] The light-emitting layer 130 of the light-emitting unit 106 has the structure shown in Embodiment 1. It is preferable that the light-emitting layer 130 of the light-emitting unit 106 has the structure shown in the first embodiment. By having this, the light emitting element 250 becomes a light emitting element with high luminous efficiency, which is preferable.

[0161] 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, it exhibits high light emitting brightness with a small current value. In addition, the light-emitting units 106 and 108 may have different guest materials. In this case, the light emitting element 250 becomes a light emitting element that emits multicolor light, which is preferable. The gate is designed to emit white light with high luminance, or at least light having red, green, and blue components. It is preferable to select a stainless steel material.

[0162] The light-emitting unit 106, the light-emitting unit 108, and the charge generating layer 115 are formed by evaporation ( (including vacuum deposition), inkjet printing, coating, gravure printing, etc. can be done.

[0163] Note that the structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. You can be there.

[0164] (Embodiment 3) In this embodiment mode, a light-emitting element having a different structure from those shown in Embodiment Modes 1 and 2 will be described. An example of this will be described below with reference to FIGS.

[0165] <Configuration example 1 of light-emitting element> 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 with the same function as the symbols shown, and in some cases the symbols are omitted. In addition, parts having similar functions are given similar reference numerals, and detailed explanations thereof will be omitted. It may be omitted.

[0166] The light emitting element 260 shown in FIG. 6 is a bottom-emitting element that extracts light toward the substrate 200. The light emitting element may be a top emission (top emission) type light emitting element 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.

[0167] When the light emitting element 260 is a bottom emission type, the electrode 101 has a function of transmitting light. It is also 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. It is preferable to do so.

[0168] 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, there are a light-emitting layer 123B, a light-emitting layer 123G, and a light-emitting layer 123R. , a hole injection layer 111, a hole transport layer 112, an electron transport layer 118, and an electron and a child injection layer 119.

[0169] The electrode 101 may be formed of a plurality of conductive layers. and a conductive layer having a function of transmitting light are preferably stacked. .

[0170] 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.

[0171] In FIG. 6, the region 221B and the region 221G are sandwiched between the electrode 101 and the electrode 102. A partition wall 145 is provided between the region 221R and the region 221R. The partition wall 145 has insulating properties. The partition wall 145 covers the end of the electrode 101 and has an opening that overlaps with the electrode. By doing so, the electrodes 101 on the substrate 200 in each region can be separated into islands. It becomes possible.

[0172] The light-emitting layer 123B and the light-emitting layer 123G are mutually separated 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 region. In the region overlapping with the wall 145, there may be a region overlapping with each other. 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.

[0173] The partition wall 145 may be formed using an inorganic or organic material as long as it has insulating properties. The inorganic material may be silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, or the like. Examples of the organic material include silicon, aluminum oxide, and aluminum nitride. For example, photosensitive resin materials such as acrylic resin or polyimide resin can be used.

[0174] The light-emitting layers 123R, 123G, and 123B each emit a different color. For example, the light-emitting layer 123R preferably has a light-emitting material that emits red light. By including a light-emitting material having a function of emitting red light, the region 221R emits red light, and Since the region 123G has a light-emitting material having a function of emitting green light, the region 221G emits green light. The light-emitting layer 123B has a light-emitting material that has a function of emitting blue light, so that the region 2 The light emitting element 260 having such a configuration is used as a display device. By using this as a device, a display device capable of full color display can be manufactured. The thickness of each of the light-emitting layers may be the same or different.

[0175] In addition, any one of the light-emitting layer 123B, the light-emitting layer 123G, and the light-emitting layer 123R or The plurality of light-emitting layers preferably have the same structure as the light-emitting layer 130 shown in the first embodiment. One or more of the light-emitting layers 123B, 123G, and 123R The light-emitting layer has the same structure as the light-emitting layer 130 shown in the first embodiment, and thus the light-emitting layer has good luminous efficiency. A good light-emitting device can be fabricated.

[0176] In addition, any one or more of the light-emitting layer 123B, the light-emitting layer 123G, and the light-emitting layer 123R The light-emitting layer may have a structure in which two or more layers are laminated.

[0177] As described above, at least one light-emitting layer has the light-emitting layer shown in Embodiment 1, and the light-emitting By using the light emitting element 260 having the layer as a pixel of a display device, a display device with high luminous 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.

[0178] 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.

[0179] Furthermore, by providing a polarizing plate on the electrode for extracting light, the reflection of external light from the light emitting element 260 can be reduced. Therefore, the contrast ratio of the display device having the light emitting element 260 can be improved. It can be done.

[0180] 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.

[0181] <Configuration example 2 of light-emitting element> Next, regarding a configuration example different from that of the light-emitting element shown in FIG. 6, the following will be described with reference to FIGS. 7(A) and 7(B). Give an explanation.

[0182] 7(A) and 7(B) are cross-sectional views showing a light-emitting element of one embodiment of the present invention. In (B), the parts having the same functions as those shown in FIG. 6 are designated by the same hatch patterns. In addition, parts with similar functions are designated by similar symbols. The detailed description may be omitted.

[0183] 7A and 7B show examples of the structure of a light-emitting element having a light-emitting layer between a pair of electrodes. The light emitting element 262a shown in (A) is a top-emitting (top-emitting) element that extracts light in the direction opposite to the substrate 200. The light emitting element 262b shown in FIG. 7(B) is a top-emission type light emitting element. However, the present invention One embodiment is not limited to this, and light emitted by the light emitting element may be emitted from the substrate 200 on which the light emitting element is formed. It may also be a dual emission type in which light is extracted from both the top and bottom.

[0184] The light emitting element 262a and the light emitting element 262b are formed by providing an electrode 101 and an electrode 102 on a substrate 200. , electrode 103, and electrode 104. Also, between electrode 101 and electrode 102, and At least a light-emitting layer is formed between the electrode 102 and the electrode 103 and between the electrode 102 and the electrode 104. The layer 130 and the charge generating layer 115 are also included. The layer 130 and the charge generating layer 115 are also included. The layer 130 and the charge transport layer 115 are also included. 2, a light-emitting layer 140, 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 .

[0185] The electrode 101 includes a conductive layer 101a and a conductive layer 101b that is in contact with the conductive layer 101a. The electrode 103 includes a conductive layer 103a and a conductive layer 103b on and in contact with the conductive layer 103a. The electrode 104 has a conductive layer 104a and a conductive layer 103b on the conductive layer 104a. and an insulating layer 104b.

[0186] The light emitting element 262a shown in FIG. 7(A) and the light emitting element 262b shown in FIG. 7(B) are The area 222B sandwiched between the electrode 101 and the electrode 102, and the area 222B sandwiched between the electrode 102 and the electrode 103 and a region 222R sandwiched between the electrode 102 and the electrode 104. The partition wall 145 has an insulating property. The partition wall 145 is provided between the electrode 101 and the electrode 1 The separator 145 covers the end of the electrode 103 and the electrode 104 and has an opening that overlaps with the electrode. By doing so, the electrodes on the substrate 200 in each region can be separated into islands. This becomes:

[0187] The light emitting element 262a and the light emitting element 262b are arranged in the regions 222B, 222G, and The optical element 224B and the optical element 224C are arranged in the direction in which the light emitted from the region 222R is extracted. The substrate 220 has the optical element 224G and the optical element 224R. The light emitted from the region 222B is emitted to the outside of the light emitting element through each optical element. The light coming from the region 222G is emitted through the optical element 224B. The light emitted through 224G and emitted from the region 222R is reflected by the optical element 224R. It is ejected.

[0188] Furthermore, the optical elements 224B, 224G, and 224R are configured to For example, the optical element 224B has a function of selectively transmitting light of a specific color. The light emitted from the region 222B through the optical element 22 is blue light. The light emitted from the area 222G via the optical element 4G is green light. The light emitted from the region 222R via the element 224R is red light.

[0189] The optical elements 224R, 224G, and 224B may include, for example, a colored layer ( Color filters, bandpass filters, multilayer filters, etc. can be used. In addition, a color conversion element can be applied to the optical element. The color conversion element is an optical element that converts light into light with a longer wavelength than the wavelength of the light. By using quantum dots, the color reproducibility of the display device can be improved. can be increased.

[0190] It should be noted that a plurality of optical elements are provided on the optical element 224R, the optical element 224G, and the optical element 224B. Other optical elements may be provided, such as a circular polarizer or an anti-reflection film. The circular polarizer can be provided on the side of the display device from which light emitted by the light emitting element is extracted. When the display device is turned on, light incident from outside the device is reflected inside the device and emitted to the outside. Furthermore, by providing an anti-reflection film, the phenomenon of reflection on the surface of the display device can be prevented. This can weaken external light, allowing the light emitted by the display device to be clearly observed.

[0191] In addition, in FIG. 7(A)(B), the light emitted from each region via each optical element is Light exhibiting color (B), light exhibiting green (G), and light exhibiting red (R), respectively. This is shown schematically by dashed arrows.

[0192] In addition, a light-shielding layer 223 is provided between each optical element. The light-shielding layer 223 is formed to prevent light from entering from adjacent regions. It should be noted that the light-shielding layer 223 may not be provided. stomach.

[0193] 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.

[0194] The substrate 200 and the substrate 220 having the optical element are the same as those in the first embodiment. That's fine.

[0195] Furthermore, the light emitting element 262a and the light emitting element 262b have a microcavity structure. .

[0196] <Microcavity structure> The light emitted from the light-emitting layer 130 and the light-emitting layer 140 is incident on a pair of electrodes (for example, electrode 10 The light emitting layer 130 and the light emitting layer 140 are resonated between the electrode 101 and the electrode 102. For example, the reflection area of ​​the electrode 101 is formed at a position where light of a desired wavelength is intensified. the optical distance from the reflecting area of ​​the electrode 102 to the light emitting area of ​​the light emitting layer 130; 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 region of the electrode 101 to the light-emitting layer 140 can be intensified. and the optical distance from the reflective area of ​​the electrode 102 to the light-emitting area of ​​the light-emitting layer 140. By adjusting the optical distance, it is possible to obtain light of a desired wavelength from the light emitting layer 140. 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 140 are stacked, the optical distances of the light emitting layer 130 and the light emitting layer 140 are It is preferable to optimize the separation.

[0197] In the light emitting element 262a and the light emitting element 262b, the conductive layer (conductive layer 1) is formed in each region. By adjusting the thickness of the light-emitting layer 130, the conductive layer 101b, the conductive layer 103b, and the conductive layer 104b, In addition, it is possible to enhance the light of a desired wavelength among the light emitted from the light emitting layer 140. The thickness of at least one of the hole injection layer 111 and the hole transport layer 112 is made different in the region. By doing so, the light emitted from light-emitting layer 130 and light-emitting layer 140 may be intensified.

[0198] For example, the electrodes 101 to 104 are made of a conductive material having a function of reflecting light. When the refractive index is smaller than that of the light-emitting layer 130 or the light-emitting layer 140, the electrode The thickness of the conductive layer 101b of the electrode 101 is set so that the optical distance between the electrode 101 and the electrode 102 is m B λ B / 2(m B is a natural number, λ B represent the wavelengths of light to be intensified in region 222B, respectively) and Similarly, the thickness of the conductive layer 103b of the electrode 103 is adjusted to be equal to the thickness of the conductive layer 103b of the electrode 103. The optical distance between the electrode 102 is m G λ G / 2(m G is a natural number, λ G is strong in the area 222G The wavelength of the light emitted from the electrode 104 is adjusted to be 100 nm. The thickness of the electrode 104b is set such that the optical distance between the electrode 104 and the electrode 102 is m R λ R / 2(m R is self natural number, λ R and represent the wavelengths of the light to be intensified in the region 222R).

[0199] As described above, a microcavity structure is provided, and the optical distance between a pair of electrodes in each region is adjusted. By adjusting the thickness, light scattering and absorption near each electrode are suppressed, resulting in high light extraction efficiency. In the above structure, the conductive layer 101b and the conductive layer 103 The conductive layer 104b preferably has a function of transmitting light. The materials constituting the conductive layers 103b, 104b may be the same as each other. The conductive layers 101b, 103b, and 104b may be different from each other. Each of these may have a structure in which two or more layers are laminated.

[0200] The light emitting element 262a shown in FIG. 7(A) is a top emission type light emitting element, and therefore is conductive. The layer 101a, the conductive layer 103a, and the conductive layer 104a may have a function of reflecting light. It is also preferable that the electrode 102 has a function of transmitting light and a function of reflecting light. is preferred.

[0201] In addition, the light emitting element 262b shown in FIG. 7B is a bottom emission type light emitting element, and therefore is conductive. The layer 101a, the conductive layer 103a, and the conductive layer 104a have a function of transmitting light and a function of reflecting light. It is preferable that the electrode 102 has a function of reflecting light. preferable.

[0202] In the light-emitting element 262a and the light-emitting element 262b, the conductive layer 101a and the conductive layer 10 The same material may be used for the conductive layer 3a or the conductive layer 104a, or different materials may be used. When the same material is used for the conductive layer 101a, the conductive layer 103a, and the conductive layer 104a, the light emitting element The manufacturing costs of the conductive layer 101a and the light emitting element 262a and the light emitting element 262b can be reduced. The conductive layer 103a and the conductive layer 104a may each have a structure in which two or more layers are stacked. stomach.

[0203] 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. It is preferable that the light emitting element 262a and the light emitting element 262b have the structure shown in The light-emitting layer 130 has the structure described in Embodiment 1, so that the light-emitting element exhibits high luminous efficiency. can be produced.

[0204] The light-emitting layer 130 and the light-emitting layer 140 are, for example, the light-emitting layer 140a and the light-emitting layer 140b. In this way, two layers may be laminated on one or both sides. 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 containing multiple colors. The light-emitting material used for each light-emitting layer is selected so that the light emitted by the light-emitting layer 140 becomes white. It is preferable to select

[0205] In addition, the light-emitting layer 130 or the light-emitting layer 140 may have a structure in which three or more layers are laminated on one side or both sides. The light-emitting layer may be made of any material, or may include a layer that does not contain a light-emitting material.

[0206] As described above, the light-emitting element 262a or the light-emitting element 262b having the light-emitting layer structure shown in Embodiment 1 By using the optical element 262b as a pixel of a display device, a display device with high luminous 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.

[0207] Other configurations of the light emitting element 262a and the light emitting element 262b are as follows: 260, or the structures of the light-emitting elements shown in Embodiments 1 and 2 may be taken into consideration. stomach.

[0208] Note that the structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. You can be there.

[0209] (Fourth embodiment) 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. 10 will be used to explain.

[0210] <Display device configuration example 1> 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. 8A. 1 and a cross-sectional view taken along dashed line CD. The display device 600 includes a drive circuit section (signal line The display device includes a driver circuit portion 601, a scanning line driver circuit portion 603, and a pixel portion 602. The signal line driver circuit portion 601, the scanning line driver circuit portion 603, and the pixel portion 602 are It has the function of controlling light emission.

[0211] The display device 600 also includes an element substrate 610, a sealing substrate 604, a sealant 605, The device has an area 607 surrounded by a sealing material 605, wiring 608, and an FPC 609. do.

[0212] The lead wiring 608 is connected to the signal line driver circuit portion 601 and the scanning line driver circuit portion 603. This is the wiring for transmitting the input signal, and is connected to the external input terminal FPC609. It receives the FP signal, clock signal, start signal, reset signal, etc. Although only C609 is shown, FPC609 has a printed wiring board (PWB). A wired wiring board may be installed.

[0213] The signal line driver circuit portion 601 includes an N-channel transistor 623 and a P-channel transistor A CMOS circuit is formed by combining this transistor 624. The path section 601 or the scanning line driving circuit section 603 may be implemented by various CMOS circuits, PMOS circuits, or In this embodiment, a driving circuit section is provided on the substrate. Although the display device shown has the formed driver and pixel on the same surface, this is not necessarily required. In addition, the drive circuit section can be formed externally rather than on the substrate.

[0214] The pixel portion 602 includes a switching transistor 611 and a current control transistor. a lower part electrically connected to the drain of the current control transistor 612; A partition wall 614 is formed to cover the edge of the lower electrode 613. The partition wall 614 can be made of a positive photosensitive acrylic resin film.

[0215] 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 to have a radius of curvature (0.2 μm or more and 3 μm or less). It is preferable that the partition wall 614 is made of a negative photosensitive resin or a polyimide. Any of the di-type photosensitive resins can be used.

[0216] The structure of the transistors (transistors 611, 612, 623, and 624) is For example, a staggered transistor may be used. There is no particular limitation on the polarity, and it has N-channel and P-channel transistors. and either an N-channel transistor or a P-channel transistor. A structure consisting of only one of the two may also be used. For example, an amorphous semiconductor film or a crystalline semiconductor film can be used. Semiconductor materials include group 14 (silicon, etc.) semiconductors, compound semiconductors (oxide As the transistor, for example, An energy gap of 2 eV or more, preferably 2.5 eV or more, and more preferably 3 eV or more By using the oxide semiconductor, the off-state current of the transistor can be reduced. As the oxide semiconductor, In-Ga oxide, In-M-Zn oxide (M is , aluminum (Al), gallium (Ga), yttrium (Y), zirconium (Zr ), lanthanum (La), cerium (Ce), tin (Sn), hafnium (Hf), or nickel Examples include neodymium (Nd).

[0217] 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.

[0218] The EL layer 616 can be formed by a deposition method (including a vacuum deposition method) using a deposition mask, a droplet discharge method, or the like. (also called inkjet method), coating methods such as spin coating, gravure printing, 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).

[0219] The lower electrode 613, the EL layer 616, and the upper electrode 617 form a light-emitting element 618. The light emitting element 618 has the structure of any one of the first to third embodiments. In addition, when a plurality of light-emitting elements are formed in a pixel portion, the same as those in Embodiments 1 to 4 are preferably used. The light-emitting element according to the third embodiment and the light-emitting element having other structures are both included. That's fine.

[0220] In addition, by bonding the sealing substrate 604 to the element substrate 610 with the sealing material 605, The light-emitting element is disposed in an area 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealing material 605. The region 607 is filled with a filler. In addition to being filled with an inert gas (nitrogen, argon, etc.), it can also be used as a sealing material 605. They may also be filled with UV or heat curable resins that can be used for various applications, such as PVC ( Polyvinyl chloride) resin, acrylic resin, polyimide resin, epoxy resin, Silicone resin, PVB (Polyvinyl Butyral) resin, or EVA (Ethylene Vinyl A recess is formed in the sealing substrate, and a desiccant (acetate) resin is placed therein. By providing this, deterioration due to the influence of moisture can be suppressed, which is a preferable configuration.

[0221] 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.

[0222] It is preferable to use epoxy resin or glass frit for the sealing material 605. In addition, it is desirable that these materials be as impermeable to moisture and oxygen as possible. In addition, the material used for the sealing substrate 604 may be a glass substrate, a quartz substrate, or an FRP (Fiber Reinforced Plastic) substrate. Reinforced Plastics), PVF (Polyvinyl Fluoride), Poly A plastic substrate made of ester, acrylic or the like can be used.

[0223] As described above, the light emitting element and the optical element described in any of the first to third embodiments are used. A display device can be obtained.

[0224] <Configuration example 2 of the display device> 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.

[0225] FIG. 9(A) shows a substrate 1001, an underlying insulating film 1002, a gate insulating film 1003, a gate electrode 1004, and a gate electrode 1006. Poles 1006, 1007, 1008, a first interlayer insulating film 1020, and 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.

[0226] In addition, in FIG. 9A, as an example of an optical element, a colored layer (a red colored layer 1034R, a green colored layer 1034R) is used. A transparent substrate 1033 is provided with a colored layer 1034G and a blue colored layer 1034B. 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. The light that passes through is red, green, and blue, so an image can be displayed using three colored pixels.

[0227] In FIG. 9B, as an example of an optical element, a colored layer (a red colored layer 1034R, a green colored layer The blue colored layer 1034G and the blue colored layer 1034B are formed between the gate insulating film 1003 and the first interlayer insulating film. In this example, the colored layer is formed between the substrate 1001 and the sealing substrate 1020. It may be provided between the plates 1031.

[0228] 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

[0229] In the display device described above, the substrate 1001 side on which the transistors are formed is The display device has a structure for extracting light (bottom emission type), but The display device may also have a structure in which light is extracted (top emission type).

[0230] <Configuration example 3 of the display device> An example of a cross-sectional view of a top-emission type display device is shown in Figures 10(A) and 10(B). 9(A) and 9(B) are cross-sectional views illustrating a display device of one embodiment of the present invention. 1, the driving circuit section 1041, the peripheral section 1042, etc. are omitted.

[0231] In this case, the substrate 1001 can be a substrate that does not transmit light. Until the connection electrode that connects to the anode of the optical element is fabricated, it is a bottom emission type display device. Then, a third interlayer insulating film 1037 is formed to cover the electrode 1022. This insulating film may also have a role of planarization. In addition to the same material as the interlayer insulating film 2, various other materials can be used.

[0232] 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) can be used. In the case of a device, the lower electrodes 1024R, 1024G, and 1024B have a function of reflecting light. In addition, an upper electrode 1026 is provided on the EL layer 1028. The electrode 1026 has a function of reflecting light and a function of transmitting light. A microcavity structure is adopted between 24G, 1024B and the upper electrode 1026, It is desirable to increase the light intensity at a particular wavelength.

[0233] In the top emission structure shown in FIG. 10(A), the colored layer (red colored layer 1034 A sealing substrate 1031 provided with a green colored layer 1034R, a green colored layer 1034G, and a blue colored layer 1034B The sealing substrate 1031 has a shielding layer positioned between the pixels. An optical layer 1035 may be provided. Note that the sealing substrate 1031 may be a light-transmitting substrate. It is suitable.

[0234] In addition, in FIG. 10(A), a plurality of light emitting elements and colored light emitting elements are provided. Although the configuration in which a layer is provided is shown as an example, the present invention is not limited to this. For example, as shown in FIG. In this case, the green color layer is not provided, and only the red color layer 1034R and the blue color layer 1034B are provided. It is also possible to use a configuration in which a full color display is performed using three colors, red, green, and blue. In this way, when a light emitting element and a colored layer are provided for each of the light emitting elements, reflection of external light can be reduced. On the other hand, as shown in FIG. 10(B), In the case where a red colored layer and a blue colored layer are provided without providing a colored layer of green, Since there is little energy loss in the light emitted from the light-emitting element, power consumption can be reduced. This has a positive effect.

[0235] The display device described above has a configuration having sub-pixels of three colors (red, green, and blue). A structure with four color sub-pixels (red, green, blue, yellow, or red, green, blue, white) In that case, the function of transmitting yellow light or blue, green, yellow, and red light may be used. It is possible to use a colored layer having a function of transmitting a plurality of lights selected from the following. When the layer has a function of transmitting a plurality of lights 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-emitting efficiency is high, a display device having such a configuration can reduce power consumption. Cut.

[0236] 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 Fat, 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, 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. It is preferable that the sealing layer is formed so as to suppress deterioration of the light emitting element 618. The sealing material 605 does not have to be provided.

[0237] Furthermore, 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 is multi-layered, it is preferable to laminate a resin and an inorganic material.

[0238] Note that the configuration shown in this embodiment may be appropriately combined with other embodiments or other configurations in this embodiment. Combinations are possible.

[0239] (Embodiment 5) In this embodiment, a display module, an electronic device, a light-emitting element, and a display device each including a light-emitting element of one embodiment of the present invention will be described. The optical device and the lighting device will be described with reference to FIGS.

[0240] <Explanation about the display module> The display module 8000 shown in FIG. 11 includes an upper cover 8001 and a lower cover 8002. Between them, the touch sensor 8004 connected to FPC8003 and the touch sensor 8005 connected to FPC8006 are A display device 8006, a frame 8009, a printed circuit board 8010, and a battery 8011 are included. do.

[0241] The light-emitting element of one embodiment of the present invention can be used for the display device 8006, for example.

[0242] The upper cover 8001 and the lower cover 8002 are connected to the touch sensor 8004 and the display device 8005. The shape and dimensions can be changed appropriately to match the size of 006.

[0243] The touch sensor 8004 is a resistive or capacitive touch sensor mounted on the display device 8 8006. In addition, the display device 8006 can be used as an opposing substrate (sealing substrate). It is also possible to provide a touch sensor function. It is also possible to provide an optical sensor in each pixel to form an optical touch sensor.

[0244] The frame 8009 has a function of protecting the display device 8006 and also a function of preventing the operation of the printed circuit board 8010. It also functions as an electromagnetic shield to block electromagnetic waves generated by the frame. The frame 8009 may also function as a heat sink.

[0245] The printed circuit board 8010 includes a power supply circuit, a signal circuit for outputting a video signal and a clock signal. The power supply circuit is provided with a signal processing circuit. Alternatively, the power source may be a battery 8011 provided separately. This can be omitted if a commercial power source is used.

[0246] In addition, the display module 8000 includes components such as a polarizing plate, a retardation plate, and a prism sheet. It may also be provided in addition.

[0247] <Electronic device instructions> 12(A) to 12(G) are diagrams showing electronic devices. These electronic devices are housed in a housing. A body 9000, a display unit 9001, a speaker 9003, operation keys 9005 (power switch, includes an operation switch), a connection terminal 9006, a sensor 9007 (force, displacement, position, speed, Acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electricity Measures field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared 9008, etc. Also, the sensor 9 007 may have a function of measuring biological information such as a pulse sensor or a fingerprint sensor.

[0248] The electronic devices shown in FIGS. 12A to 12G can have various functions. For example, functions to display various information (still images, videos, text images, etc.) on the display, Sensor function, calendar, date or time display function, various software ( It has the function of controlling processing by using a program, wireless communication function, and various functions using wireless communication function. Functions for connecting to computer networks, transmitting various data using wireless communication functions, or receiving the program or data recorded on the recording medium, and It should be noted that the functions shown in FIGS. 12(A) to 12(G) can be implemented. The functions that the electronic device shown in the figure can have are not limited to these, and it may have various functions. Although not shown in FIGS. 12(A) to 12(G), the electronic device may include: The electronic device may have a plurality of display units. The function to take pictures, take videos, and save the images to a recording medium (external or built-in to the camera) ) and a function to display the captured image on the display unit.

[0249] The electronic devices shown in FIGS. 12A to 12G will be described in detail below.

[0250] FIG. 12A is a perspective view showing a mobile information terminal 9100. The display portion 9001 is flexible. The display unit 9001 can be incorporated along the screen. It is equipped with a touch panel, and can be operated by touching the screen with a finger or a stylus. By touching the icon displayed on the display 9001, the application can be started. can.

[0251] 12B 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, it can be used as a smartphone. Although the speaker 9003, the connection terminal 9006, the sensor 9007, etc. are omitted in the illustration, It can be installed in the same position as the mobile information terminal 9100 shown in FIG. The information terminal 9101 can display text and image information on multiple surfaces. For example, Three operation buttons 9050 (also called operation icons or simply icons) are displayed on the display unit 900. 9051 shown in a dashed rectangle can be displayed on one side of the display unit 90. 01. An example of the information 9051 is an e-mail A display that notifies you of incoming calls, SNS (social networking services), etc. , subject of email or SNS, sender name of email or SNS, date and time, time, There are also displays showing the remaining battery level, the strength of the received signal, etc. Even if you display operation buttons 9050 instead of information 9051 at the displayed position, good.

[0252] The housing 9000 is made of a material such as alloy, plastic, or ceramic. Reinforced plastic can also be used as the plastic. Carbon Fiber Reinforced Resin Composite (CFRP), a type of carbon fiber composite Carbon fiber reinforced plastics (CFRP) have the advantage of being lightweight and corrosion-resistant. Other reinforced plastics include glass fiber reinforced plastics and aramid fiber reinforced plastics. Examples of alloys include aluminum alloys and Magnesium alloys include non-metallic alloys containing zirconium, copper, nickel, and titanium. Amorphous alloys (also called metallic glasses) have excellent 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. It is an alloy having a substantially amorphous atomic structure. The alloy material is poured into the housing mold and solidified to form a part of the housing with bulk solidified amorphous alloy. Amorphous alloys include zirconium, copper, nickel, titanium, as well as beryllium and silicon. Cobalt, niobium, boron, gallium, molybdenum, tungsten, manganese, iron, cobalt The amorphous alloy may contain yttrium, vanadium, phosphorus, carbon, etc. Not limited to solid casting, but also vacuum deposition, sputtering, electrolytic plating, electroless plating, etc. The amorphous alloy may be formed by the above method. As long as the alloy maintains a state free of crystallites, it may contain microcrystals or nanocrystals. , both complete solid solution alloys with a single solid phase structure and partial solutions with two or more phases. The housing 9000 is made of an amorphous alloy, which gives it high elasticity. Therefore, even if the portable information terminal 9101 is dropped, the housing 9000 is made of an amorphous alloy. If the impact is applied, the mobile information terminal 910 will return to its original shape even if it is temporarily deformed at the moment of impact. 1 can improve the impact resistance.

[0253] 12C is a perspective view showing a portable information terminal 9102. The portable information terminal 9102 is , and has the function of displaying information on three or more surfaces of the display unit 9001. An example is shown in which information 9053 and information 9054 are displayed on different sides. The user of the portable information terminal 9102 stores the portable information terminal 9102 in the breast pocket of his / her clothes. In this state, the display (information 9053 in this case) can be confirmed. The telephone number or name of the caller is displayed in a position that can be observed from above the mobile information terminal 9102. The user can view the display without taking the mobile information terminal 9102 out of his pocket. You can check the call and decide whether to accept it or not.

[0254] 12(D) is a perspective view showing a wristwatch-type portable information terminal 9200. The 9200 is suitable for mobile phone calls, e-mail, document browsing and writing, music playback, and internet communications. It is possible to run various applications such as computer games. The display surface of the display unit 9001 is curved, and the display is performed along the curved display surface. In addition, the portable information terminal 9200 can perform short-distance wireless communication according to a communication standard. For example, by communicating with a wireless headset, handset The mobile information terminal 9200 also has a connection terminal 9006. It has a connector and can directly exchange data with other information terminals. Charging can also be performed via the connection terminal 9006. It may also be possible to supply power wirelessly without going through 6.

[0255] 12(E), (F), and (G) are perspective views showing a foldable portable information terminal 9201. 12(E) is a perspective view of the portable information terminal 9201 in an unfolded state, and FIG. (F) shows the mobile information terminal 9201 being changed from one of the unfolded state and the folded state to the other. 12(G) is a perspective view of the portable information terminal 9201 in a folded state. The portable information terminal 9201 is highly portable when folded, and is easily portable when unfolded. When the display is turned on, the seamless, wide display area provides excellent visibility of the display. The display unit 9001 of the display device 01 is made up of three housings 9000 connected by hinges 9055. The two housings 9000 are supported by the hinge 9055. This allows the portable information terminal 9201 to be reversibly transformed from an unfolded state to a folded state. For example, the portable information terminal 9201 can be bent with a radius of curvature of 1 mm or more and 150 mm or less. It can be done.

[0256] Furthermore, examples of electronic devices include television sets (televisions or television receivers) (also called "computer"), computer monitors, digital cameras, digital video cameras, Digital photo frames, mobile phones (also called mobile phones or mobile phone devices), goggle-type Displays (head-mounted displays), portable game consoles, portable information terminals, audio playback Examples include live video equipment, large gaming machines such as pachinko machines, etc.

[0257] Furthermore, the electronic device of one embodiment of the present invention may include a secondary battery and may perform contactless power transmission. It is preferable that the secondary battery can be charged using the power supply.

[0258] As the secondary battery, for example, a lithium polymer battery (lithium ion battery) using a gel electrolyte is used. Lithium-ion secondary batteries such as lithium-ion polymer batteries, lithium-ion batteries, nickel-metal hydride batteries batteries, nickel-cadmium batteries, organic radical batteries, lead-acid batteries, secondary air batteries, nickel-zinc batteries, silver-zinc batteries Examples include lead batteries.

[0259] The electronic device according to one embodiment of the present invention may include an antenna. By doing so, it is possible to display images, information, etc. on the display unit. , the antenna may be used for contactless power transfer.

[0260] Furthermore, since the electronic device or lighting device of one embodiment of the present invention is flexible, it can be easily installed inside a house or a building. It can also be incorporated into walls or exterior walls, or along the curved surfaces of the interior or exterior of a vehicle. For example, installing lighting on the dashboard, windshield, ceiling, etc. of a car can This can be done.

[0261] <Explanation about the light-emitting device> FIG. 13(A) is a perspective view of a light emitting device 3000 according to this embodiment. The cross-sectional view corresponding to the dashed line EF is shown in FIG. 13(B). In A), some of the components are shown with dashed lines to avoid cluttering the drawing.

[0262] The light emitting device 3000 shown in FIGS. 13(A) and 13(B) includes a substrate 3001 and a light emitting layer on the substrate 3001. an optical element 3005, a first sealing region 3007 provided on the periphery of the light emitting element 3005, and a second sealing region 3007. and a second sealing region 3009 provided on the outer periphery of the first sealing region 3007.

[0263] The light emitted from the light emitting element 3005 is incident on either the substrate 3001 or the substrate 3003. In Fig. 13(A) and (B), light is emitted from the light emitting element 3005. A configuration in which light is emitted downward (toward the substrate 3001) will be described.

[0264] As shown in FIGS. 13A and 13B, the light emitting device 3000 includes a light emitting element 3005. A double sealing structure is arranged surrounded by a first sealing region 3007 and a second sealing region 3009. The double sealing structure prevents external impurities (e.g. However, the first sealing region 300 7 and the second sealing region 3009 are not necessarily provided. It may also be configured with only 007.

[0265] In FIG. 13B, the first sealing region 3007 and the second sealing region 3009 are , and are provided in contact with the substrate 3001 and the substrate 3003. However, the present invention is not limited to this. For example, one or both of the first sealing region 3007 and the second sealing region 3009 may be formed on the substrate 30. The insulating film or conductive film formed above the insulating film 01 may be provided in contact with the insulating film or conductive film. Alternatively, one or both of the first sealing region 3007 and the second sealing region 3009 may be formed on the substrate. It may be configured to be in contact with the insulating film or conductive film formed below 3003. stomach.

[0266] The substrate 3001 and the substrate 3003 are the same as the substrate 200 described in the previous embodiment. The light emitting element 3005 may have the same structure as the substrate 220. The light-emitting element may have the same configuration as that described above.

[0267] The first sealing region 3007 is made of a material containing glass (for example, glass frit, glass The second sealing region 3009 may be made of a material containing resin. By using a material containing glass for the first sealing region 3007, In addition, the second sealing region 3009 can be made of a material containing a resin. By using this material, it is possible to improve the impact resistance and heat resistance. The first sealing region 3007 and the second sealing region 3009 are not limited to this. The first sealing region 3009 is formed of a material containing resin, and the second sealing region 3009 is formed of a material containing glass. Good too.

[0268] The glass frit may be, for example, magnesium oxide, calcium oxide, Strontium oxide, barium oxide, cesium oxide, sodium oxide, potassium oxide, acid Boron oxide, vanadium oxide, zinc oxide, tellurium oxide, aluminum oxide, silicon dioxide, acid Lead oxide, tin oxide, phosphorus oxide, ruthenium oxide, rhodium oxide, iron oxide, copper oxide, manganese dioxide ZnO, molybdenum oxide, niobium oxide, titanium oxide, tungsten oxide, bismuth oxide, Zirconium oxide, lithium oxide, antimony oxide, lead borate glass, tin phosphate glass , vanadate glass, or borosilicate glass. It is preferable that both contain one or more transition metals.

[0269] The glass frit may be formed by applying a frit paste to a substrate, for example. This is then subjected to heat treatment or laser irradiation. The resin is diluted with an organic solvent (also called a binder). It is also possible to use a laser beam having an absorbent added thereto that absorbs light of the wavelength of the laser beam. It is preferable to use, for example, an Nd:YAG laser or a semiconductor laser as the laser. Furthermore, the shape of the laser beam may be circular or rectangular.

[0270] Examples of materials containing the above-mentioned resins include polyester, polyolefin, and poly. Amide (nylon, aramid, etc.), polyimide, polycarbonate or acrylic resin, Polyurethane and epoxy resins can be used. Alternatively, siloxane such as silicone can be used. Materials containing resins with SAN bonds can be used.

[0271] In addition, either one or both of the first sealing region 3007 and the second sealing region 3009 When a material containing glass is used for the substrate 3001, the thermal expansion coefficient of the material containing glass and the substrate 3001 is By adopting the above-mentioned configuration, the material or substrate containing glass is prevented from being damaged by thermal stress. This can prevent cracks from occurring in the plate 3001.

[0272] For example, the first sealing region 3007 may be made of a material containing glass, and the second sealing region 3009 may be made of a material containing glass. When a material containing resin is used, the following excellent effects are obtained.

[0273] The second sealing region 3009 is closer to the periphery of the light emitting device 3000 than the first sealing region 3007. The light emitting device 3000 is provided on the side closer to the outer periphery. Therefore, the distortion becomes large on the outer peripheral side of the light emitting device 3000, that is, on the second The first sealing region 3009 is sealed with a material containing resin, and the second sealing region 3009 is sealed with a material containing resin. By sealing the first sealing region 3007 provided on the inside with a material containing glass, The light emitting device 3000 is less likely to break even if distortion due to external force or the like occurs.

[0274] As shown in FIG. 13(B), the substrate 3001, the substrate 3003, the first sealing region 30 A first region 3011 is formed in the region surrounded by the second sealing region 3007 and the second sealing region 3009. In addition, the substrate 3001, the substrate 3003, the light emitting element 3005, and the first sealing region 300 In the area surrounded by 7, a second area 3013 is formed.

[0275] The first region 3011 and the second region 3013 may be filled with, for example, a rare gas or a nitrogen gas. It is preferable that the container is filled with an inert gas such as acrylic or epoxy resin. It is preferable that the first region 3011 and the second region 3013 are filled with Preferably, the pressure is reduced below atmospheric pressure.

[0276] Also, a modified example of the configuration shown in Fig. 13(B) is shown in Fig. 13(C). FIG. 3 is a cross-sectional view showing a modified example of the device 3000.

[0277] In FIG. 13(C), a recess is provided in a part of the substrate 3003, and a desiccant 3018 is provided in the recess. The rest of the configuration is the same as that shown in FIG.

[0278] Desiccants 3018 are substances that adsorb moisture by chemical adsorption or by physical adsorption. Therefore, a substance that absorbs moisture can be used. For example, a desiccant 3018 can be used. The substances that can be used include oxides of alkali metals and oxides of alkaline earth metals (oxides calcium and barium oxide), sulfates, metal halides, perchlorates, zeolites, Examples include silica gel.

[0279] <Explanation about lighting equipment> FIG. 14 shows an example in which the light-emitting element is used as an indoor lighting device 8501. Since the surface area can be increased, a large-area lighting device can be formed. By using a housing having the above structure, a lighting device 8502 having a curved light-emitting area can be formed. The light-emitting element shown in this embodiment mode has a thin film shape, and the housing can be designed with a high degree of freedom. Therefore, it is possible to create lighting devices with various elaborate designs. A large lighting device 8503 may be provided on the wall. A touch sensor may be provided in 503 to turn the power on or off.

[0280] In addition, by using light-emitting elements on the surface of the table, it has the function of a table. The lighting device 8504 can be used as a lighting device. This allows the lighting device to function as furniture.

[0281] As described above, a display module, a light-emitting device, and a light-emitting element according to one embodiment of the present invention are used. The electronic device and the lighting device can be obtained. The applicable lighting device and the electronic device are as follows: The present invention is not limited to the present embodiment, but can be applied to electronic devices in all fields. be.

[0282] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. You can be there. [Example]

[0283] In this example, a manufacturing example of a light-emitting element according to one embodiment of the present invention and a comparative light-emitting element will be described. The structure of the light-emitting element fabricated in this example is the same as that shown in Figure 1. The details of the element structure are shown in Table 1. The structures and abbreviations of the compounds used are shown below.

[0284] [ka]

[0285] [Table 1]

[0286] <Fabrication of light-emitting element> A method for manufacturing the light-emitting element manufactured in this example will be described below.

[0287] <Fabrication of Light-Emitting Element 1> 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).

[0288] 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 co-deposition was carried out so that the thickness was 60 nm.

[0289] Next, a hole transport layer 112 was formed on the hole injection layer 111 using 9-[3-(9-phenyl-9 H-fluoren-9-yl)phenyl]-9H-carbazole (abbreviation: mCzFLP) The deposition was carried out to a thickness of 20 nm.

[0290] Next, a light-emitting layer 130 containing 4,6mCzP2Pm and Ir(d mpimpt-Me)3 and a weight ratio of (4.6mCzP2Pm:Ir(dmpimpt- The deposition was carried out by co-evaporation so that the ratio of Me) to 3) was 1:0.1 and the thickness was 40 nm. In the phosphorescent layer 130, Ir(dmpimpt-Me)3 is the first organic compound. compound and 4,6mCzP2Pm is the second organic compound.

[0291] Next, on the light-emitting layer 130, 4,6mCzP2Pm was deposited to a thickness of 2 The deposition was carried out in sequence so that the thickness of BPhen was 10 nm, and then BPhen was 10 nm. On the electron transport layer 118, LiF was evaporated to a thickness of 1 nm as the electron injection layer 119. I arrived.

[0292] 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.

[0293] Next, in a glove box with a nitrogen atmosphere, a glass substrate for sealing is attached to an organic By using an EL sealant to fix the organic material to the glass substrate, the electrodes and EL Specifically, a sealant was applied around the organic material formed on the glass substrate. The glass substrate and a glass substrate for sealing are bonded together, and ultraviolet light having a wavelength of 365 nm is applied. 6J / cm 2 The light-emitting element 1 was obtained by the above steps. Ta.

[0294] <Fabrication of Comparative Light-Emitting Device 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 was 4 mm 2 (2mm x 2mm).

[0295] 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 co-deposition was carried out so that the thickness was 60 nm.

[0296] Next, mCP was deposited on the hole injection layer 111 to form a hole transport layer 112 with a thickness of 20 nm. It was evaporated like this.

[0297] Next, a light-emitting layer 130 containing mCP and Ir (dmpimpt- The weight ratio of mCP:Ir(dmpimpt-Me)3 was 1:0.08. In the light-emitting layer 130, Ir( dmpimpt-Me)3 is a phosphorescent compound that acts as a guest material, and mCP is a host material. is.

[0298] Next, on the light-emitting layer 130, a layer of mDBTBIm-II and Ir( dmpimpt-Me)3 and the weight ratio (mDBTBIm-II:Ir(dmpimpt -Me)3) in a ratio of 1:0.08 and to a thickness of 10 nm, Subsequently, BPhen was evaporated to a thickness of 15 nm. As the electron injection layer 119, LiF was deposited to a thickness of 1 nm.

[0299] 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.

[0300] Next, in a glove box with a nitrogen atmosphere, a glass substrate for sealing is attached to an organic By using an EL sealant to fix the organic material to the glass substrate, the electrodes and EL The L layer was sealed in the same manner as in the light-emitting element 1. Got child 1.

[0301] <Light-emitting element characteristics> Next, the characteristics of the fabricated light-emitting element 1 and comparative light-emitting element 1 were measured. The E chromaticity was measured using a color luminance meter (Topcon, BM-5A) and the electroluminescence spectrum A multi-channel spectrometer (PMA-11, manufactured by Hamamatsu Photonics KK) was used for the measurement.

[0302] FIG. 15 shows the luminance-current density characteristics of the light-emitting element 1 and the comparative light-emitting element 1, and FIG. 16, current efficiency vs. luminance characteristics are shown in Fig. 17, power efficiency vs. luminance characteristics are shown in Fig. 18, and external quantum efficiency The luminance characteristics of the light-emitting element 1 and the comparative light-emitting element 1 are shown in FIG. 2.5mA / cm 2 The electroluminescence spectrum when a current was applied at a current density of The measurements of each light-emitting device were carried out at room temperature (an atmosphere maintained at 23°C).

[0303] Also, 500 cd / m 2 The element characteristics of the light-emitting element 1 and the comparative light-emitting element 1 are shown in the vicinity of Shown in 2.

[0304] [Table 2]

[0305] As shown in FIG. 20, the electroluminescence spectrum of the light-emitting element 1 has a peak wavelength of 545 nm. On the other hand, the comparative light-emitting element 1 exhibited a wide yellow emission with a full width at half maximum of 105 nm. The emission spectrum is a narrow blue light with a peak wavelength of 460 nm and a full width at half maximum of 52 nm. The light emitted from the comparative light-emitting element 1 was emitted from a phosphorescent compound, Ir(dmpimpt-Me The light emitted by the light-emitting element 1 is due to the phosphorescent compound Ir(dmpim)3. No emission from pt-Me)3 was observed.

[0306] Also, as shown in FIGS. 15 to 19 and Table 2, the light-emitting element 1 is driven at a lower driving voltage than the comparative light-emitting element 1. Further, the light-emitting element 1 has a higher luminous efficiency (current efficiency, power efficiency, and external quantum efficiency) than the comparative light-emitting element 1. Therefore, the light-emitting element of one aspect of the present invention having the first organic compound (Ir(d mpimpt-Me)3) and the second organic compound (4,6mCzP2Pm) is a light-emitting element with a low driving voltage, high luminous efficiency, and low power consumption.

[0307] <CV measurement results> Next, the electrochemical properties (oxidation reaction properties and reduction reaction properties) of the above compounds were measured by cyclic voltammetry (CV) measurement. For the measurement, an electrochemical analyzer (manufactured by BAS Inc., model number: ALS model 600A or 600C) was used, and a solution in which each compound was dissolved in N,N-dimethylformamide (abbreviation: DMF) was measured. In the measurement, the potential of the working electrode with respect to the reference electrode was changed within an appropriate range to obtain the oxidation peak potential and the reduction peak potential, respectively. Also, since it is estimated that the redox potential of the reference electrode is -4.9 4 eV, the HOMO level and LUMO level of each compound were calculated from this value and the obtained peak potential.

[0308] As a result of the CV measurement, the oxidation potential of 4,6mCzP2Pm was 0.95 V and the reduction potential was -2.0 6 V. Also, the HOMO level of 4,6mCzP2Pm calculated from the CV measurement was -5 .89 eV and the LUMO level was -2.88 eV. From this, it was found that 4,6mCzP2 Pm has a low LUMO level. Also, Ir(dmpimpt-Me ​​​​​​The oxidation potential of 3 was 0.24 V and the reduction potential was -2.67 V. The HOMO level of the Ir(dmpimpt-Me)3 is -5.18 eV, and the LUMO level is This indicates that Ir(dmpimpt-Me)3 has a high H It was found that mCP has an OMO level. The oxidation potential of mCP was 0.97 V. The HOMO level of mCP calculated from CV measurements was -5.91 eV. The reduction potential of P was low and no clear reduction peak was observed, so mCP had a high LUM It is assumed to have O levels.

[0309] As described above, the LUMO level of the second organic compound, 4,6mCzP2Pm, is The LUMO level is lower than that of the organic compound Ir(dmpimpt-Me)3, The HOMO level of the organic compound 4,6mCzP2Pm is the same as that of the first organic compound Ir( Therefore, the HOMO level of the light-emitting element 1 is When this compound is used in the optical layer, electrons and positive carriers injected from a pair of electrodes The holes were efficiently filled with 4,6mCzP2Pm (the second organic compound) and Ir (dmpimpt-M e) 3 (first organic compound) and 4, 6mCzP2Pm (second organic compound) were injected, respectively. Form an exciplex with Ir(dmpimpt-Me)3 (first organic compound) It is possible.

[0310] In addition, the exciplex formed by 4,6mCzP2Pm and Ir(dmpimpt-Me)3 has a LUMO level in 4,6mCzP2Pm and H in Ir(dmpimpt-Me)3 It becomes an exciplex with an OMO level. The energy difference from the HOMO level of (dmpimpt-Me)3 is 2.30 eV. This value is calculated from the peak wavelength of the electroluminescence spectrum of the light-emitting element 1 shown in FIG. This roughly coincides with the light-emitting energy (2.28 eV). The emission spectrum is formed by 4,6mCzP2Pm and Ir(dmpimpt-Me)3. The luminescence is based on the exciplex, which has a difference between the S1 and T1 levels. Since the emission energy is small, it is possible to determine the energy of the S1 and T1 levels of the exciplex (2. 28 eV).

[0311] On the other hand, the CV measurement results show that the HOMO level of Ir(dmpimpt-Me)3 is mC The LUMO level of mCP is higher than the HOMO level of P, but the LUMO level of mCP is higher than the HOMO level of Ir(dmpimpt-Me)3 Therefore, when the light-emitting element 1 using the compound in the light-emitting layer is used, the In this case, both the electrons and holes injected from the pair of electrodes are transported to the Ir(dmpi Ir(dmpimpt-Me)3 is injected into Ir(dmpimpt-Me)3, which emits light.

[0312] The light-emitting element 1 is formed of 4,6mCzP2Pm and Ir(dmpimpt-Me)3. The exciplex emits light, and the LUMO level of 4,6mCzP2Pm and Ir(dmpimpt The exciplex is excited at an energy level corresponding to the difference (2.30 eV) between the HOMO level of On the other hand, the comparative light-emitting element 1 can be formed by exciting Ir(dmpimpt-Me)3. To induce luminescence, at least the LUMO level and HOM level of Ir(dmpimpt-Me)3 must be The energy required for excitation is equivalent to the difference between the O level (2.91 eV). Element 1 can emit light at a driving voltage lower than that of the comparative light-emitting element 1.

[0313] In addition, the exciplex formed by 4,6mCzP2Pm and Ir(dmpimpt-Me)3 has an excitation energy level lower than the energy difference (3.01 eV) between the LUMO level and the HOMO level of 4,6mCzP2Pm. Therefore, by forming the exciplex, a light-emitting element with a low driving voltage can be obtained.

[0314] <Measurement of the T1 level> Next, in order to determine the T1 level of the compound used in the light-emitting layer 130, thin films of 4,6mCzP2Pm and mCP were respectively fabricated on a quartz substrate by vacuum evaporation, and the emission spectra of the thin films were measured at a low temperature (10 K).

[0315] <000​​​​​​​​​​​​​​​​​​​​​​​ The wavelength of the shortest wavelength peak (including the shoulder) of the light component was 459 nm. , the wave length of the shortest wavelength peak (including the shoulder) of the phosphorescence component of the mCP emission spectrum The length was 421 nm.

[0318] Therefore, from the above peak wavelength, the T1 level of 4,6mCzP2Pm is 2.70 eV. The T1 level of mCP was calculated to be 2.95 eV.

[0319] <Absorption and emission spectra of compounds> Next, the measurement results of the absorption spectrum and emission spectrum of Ir(dmpimpt-Me)3 The results are shown in Figure 23.

[0320] To measure the absorption and emission spectra, Ir(dmpimpt-Me)3 A dichloromethane solution was prepared by dissolving the compound, and the absorption spectrum was measured using a quartz cell. The absorption spectrum was measured using an ultraviolet-visible spectrophotometer (JASCO Corporation, V550 model). The absorption spectra of the quartz cell and the solvent were subtracted from the measured spectrum of the solution. The emission spectrum was measured using a PL-EL measurement device (manufactured by Hamamatsu Photonics). The measurement was carried out at room temperature (an atmosphere maintained at 23°C).

[0321] As shown in Figure 23, the most The absorption edge on the low energy side (long wavelength side) is around 450 nm. From the data, the absorption edge was calculated and the transition energy was estimated assuming a direct transition. The transition energy of r(dmpimpt-Me)3 was calculated to be 2.71 eV. Since mpimpt-Me3 is a phosphorescent compound, the lowest energy absorption band is This is an absorption band based on the transition to the doublet excited state. The T1 level of )3 is calculated to be 2.71 eV.

[0322] From the above measurement results, the T1 level (2.70 eV) of 4,6mCzP2Pm is mpimpt-Me)3 (2.71 eV), and The T1 level (2.71 eV) of t-Me3 is The T1 level (2.28 eV) of the exciplex formed with pt-Me3 is higher than that of the exciplex formed with 4, The LUMO level of 6mCzP2Pm and the HOMO level of Ir(dmpimpt-Me)3 The difference is larger than the difference (2.30 eV). Therefore, The exciplex formed with t-Me)3 can emit light efficiently.

[0323] <Emission quantum yield of compound> Next, the luminescence quantum yield of Ir(dmpimpt-Me)3 was measured. The measurement was carried out using 1 × 10 Ir(dmpimpt-Me)3 solution. -5 Using a toluene solution of M The measurements were performed using an absolute quantum yield measurement device (Hamamatsu Photonics, C9920-02). The wavelength was measured in the range of 350 nm to 550 nm.

[0324] As a result of the measurement, the luminescence quantum yield of Ir(dmpimpt-Me)3 was 7%. Therefore, Ir(dmpimpt-Me)3 has a low luminescence quantum yield as a phosphorescent material. It is clear that this is a material that can be used for this purpose.

[0325] On the other hand, the light-emitting element 1 is made of 4,6mCzP2Pm and Ir(dmpimpt-Me)3. It is a light-emitting device that emits light derived from an exciplex formed by Ir(dmpimpt-Me) The comparative light-emitting element 1 has a higher luminous efficiency than the comparative light-emitting element 1, which is a light-emitting element that exhibits light emission derived from the compound semiconductor layer 3. In addition, the electrons generated by the recombination of carriers (holes and electrons) injected from a pair of electrodes The probability of generating singlet excitons is up to 25%, so the light extraction efficiency to the outside is 30%. In the case of the light-emitting device 1, the external quantum efficiency is 7.5% at most. The reason why the external quantum efficiency of Light-emitting Device 1 is high is In the light-emitting element 1, carriers (holes and electrons) injected from a pair of electrodes are recombined. In addition to the emission from singlet excitons generated by the or from singlet excitons generated from triplet excitons by reverse intersystem crossing in exciplexes. That is, according to one embodiment of the present invention, the luminescence quantum yield is Even when a compound with low luminous efficiency is used, a light-emitting element with high luminous efficiency can be obtained. .

[0326] 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 emits light with a wide emission spectrum can be provided. Furthermore, one embodiment of the present invention provides a light-emitting element that operates at a low voltage and consumes low power. It can be provided. [Example]

[0327] In this example, a manufacturing example of a light-emitting element according to one embodiment of the present invention will be described. The optical element configuration is the same as that shown in Figure 1. The details of the element structure are shown in Table 3. The structures and abbreviations of the compounds are shown below. For the structures and abbreviations of other compounds, please refer to Example 1. stomach.

[0328] [ka]

[0329] [Table 3]

[0330] <Fabrication of Light-Emitting Device 2> The method for fabricating the light-emitting element 2 in this example will be described below. The only difference between this light-emitting element 1 and the light-emitting element 1 shown in FIG. 1 is the process of forming the light-emitting layer 130. The same manufacturing method was used.

[0331] The light-emitting layer 130 of the light-emitting element 2 is made of 4,6mCzP2Pm and tris[2-(1H-pi thiazol-1-yl-κN 2 )phenyl-κC]iridium(III) (abbreviation: Ir(p pz)3) and the weight ratio (4,6mCzP2Pm:Ir(ppz)3) was 1:0.2. The light-emitting layer 130 was co-deposited with Ir( ppz)3 is the first organic compound, and 4,6mCzP2Pm is the second organic compound. .

[0332] <Light-emitting element characteristics> Next, the characteristics of the fabricated light-emitting element 2 were measured. The measurement method was the same as in Example 1. be.

[0333] The luminance-current density characteristics of Light-emitting Element 2 are shown in FIG. 24, the luminance-voltage characteristics are shown in FIG. 25, and the current efficiency- The luminance characteristics are shown in Fig. 26, the power efficiency - luminance characteristics are shown in Fig. 27, and the external quantum efficiency - luminance characteristics are shown in Fig. 28 respectively. Also, a current was passed through the light - emitting element 2 at a current density of 2.5 mA / cm 2 . The electroluminescence spectrum at that time is shown in Fig. 29. The measurement of the light - emitting element was carried out at room temperature (an atmosphere maintained at 23°C) .

[0334] Also, the device characteristics of the light - emitting element 2 near 1000 cd / m 2 are shown in Table 4

[0335] [Table 4]

[0336] As shown in Fig. 29, the electroluminescence spectrum of the light - emitting element 2 showed yellow light emission with a peak wavelength of 537 nm and a full - width at half - maximum of 84 nm. Although Ir(ppz)3 used in the light - emitting element 2 is known to be a compound that emits blue light at low temperatures, the emission derived from Ir(ppz)3 was not observed

[0337] Also, as shown in Figs. 24 to 28 and Table 4, the light - emitting element 2 is driven at a low driving voltage. Also, the light - emitting element 2 shows high luminous efficiency (current efficiency, power efficiency, and external quantum efficiency ) . Therefore, the light - emitting element of one embodiment of the present invention having the first organic compound (Ir(ppz)3) and the second organic compound (4,6mCzP2Pm) is a light - emitting element with a low driving voltage, high luminous efficiency, and low power consumption

[0338] [CV measurement results] Next, the electrochemical characteristics (oxidation reaction characteristics and reduction reaction characteristics) of the above - mentioned compounds were measured by cyclic voltammetry (CV). The measurement method is the same as in Example 1 ​​​​​​ In addition, the measurement results for 4,6mCzP2Pm can be taken into consideration in Example 1.

[0339] The CV measurement results showed that the oxidation potential of Ir(ppz)3 was 0.45 V and the reduction potential was -3.17 V. In addition, the HOMO level of Ir(ppz)3 calculated from CV measurements was -5.39e V, and the LUMO level was -1.77 eV. From this, Ir(ppz)3 has a high It was found to have a HOMO level.

[0340] As described above, the LUMO level of the second organic compound, 4,6mCzP2Pm, is The LUMO level is lower than that of the organic compound Ir(ppz)3, which is the second organic compound The HOMO level of 4,6mCzP2Pm is the same as that of the first organic compound, Ir(ppz)3. Therefore, when this compound is used in the light-emitting layer as in the light-emitting element 2, The electrons and holes injected from the pair of electrodes are efficiently transported to the 4,6mCzP 2Pm (second organic compound) and Ir(ppz)3 (first organic compound), respectively. 4,6mCzP2Pm (the second organic compound) and Ir(ppz)3 (the first organic compound) ) can form an exciplex.

[0341] In addition, the difference between the LUMO level of 4,6mCzP2Pm and the HOMO level of Ir(ppz)3 This value is 2.51 eV, which is the same as the value of the electroluminescence spectrum of the light-emitting element 2 shown in FIG. This roughly matches the emission energy (2.31 eV) calculated from the peak wavelength. Therefore, the electroluminescence spectrum of the light-emitting element 2 is 4,6mCzP2Pm and Ir(ppz) The light emission is based on the exciplex formed in step 3. The exciplex has two levels, S1 and T1. Since the difference in levels is small, the emission energy is the same as the energy of the S1 and T1 levels of the exciplex. It can be considered as a neutron (2.31 eV).

[0342] In addition, the excitation energy of the exciplex formed by 4,6mCzP2Pm and Ir(ppz)3 The energy level is the energy difference between the LUMO level and the HOMO level of 4,6mCzP2Pm (3. Therefore, by forming the exciplex, a light-emitting element with a low driving voltage can be obtained. You can get a child.

[0343] <Absorption spectrum of compound> Next, the measurement results of the absorption spectrum of Ir(ppz)3 are shown in FIG.

[0344] To measure the absorption spectrum, a dichloromethane solution containing Ir(ppz)3 was The absorption spectrum was measured using a quartz cell. A spectrophotometer (V550 model, manufactured by JASCO Corporation) was used. The absorption spectra of the quartz cell and the solvent were subtracted from the absorption spectra of the quartz cell. The atmosphere was very friendly.

[0345] As shown in Figure 30, the lowest energy side of the absorption spectrum of Ir(ppz)3 The absorption edge (long wavelength side) is around 370 nm. Also, from the absorption spectrum data, The absorption edge was determined and the transition energy was estimated assuming a direct transition. The transition energy was calculated to be 3.27 eV. Ir(ppz)3 is a phosphorescent compound. Therefore, the absorption band on the lowest energy side is an absorption band based on the transition to the triplet excited state. Therefore, the T1 level of Ir(ppz)3 is calculated to be 3.27 eV from the absorption edge.

[0346] From the above measurement results, the T1 level (2.70 eV) of 4,6mCzP2Pm is pz)3 (3.27 eV) and the T1 level of 4,6mCzP2Pm (2 0.70 eV) is the T1 of the exciplex formed by 4,6mCzP2Pm and Ir(ppz)3 The LUMO level of 4,6mCzP2Pm is larger than that of Ir (p pz)3 HOMO level difference (2.51 eV) is larger than that. The exciplex formed by 2Pm and Ir(ppz)3 can emit light efficiently.

[0347] In addition, when the emission spectrum of Ir(ppz)3 was measured at room temperature, In Non-Patent Document 1, the luminescence quantum yield of Ir(ppz)3 is It is reported that the solubility of Ir(ppz)3 is less than 1% at room temperature. It is clear that the material does not emit light.

[0348] On the other hand, the light-emitting element 2 is an exciplex formed by 4,6mCzP2Pm and Ir(ppz)3. It is a light-emitting device that emits light derived from the above, and exhibits high external quantum efficiency of over 20%. The reason why the external quantum efficiency of the light-emitting element 2 is high is that in the light-emitting element 2, Originates from singlet excitons generated by the recombination of injected carriers (holes and electrons) In addition to luminescence, luminescence from triplet excitons or reverse intersystem crossing in exciplexes can occur. This is because light emission originates from singlet excitons generated from triplet excitons. That is, in one embodiment of the present invention, a compound having a low luminescence quantum yield of less than 1% is used. Even if the above is the case, a light emitting element having high luminous efficiency can be obtained.

[0349] 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 with low driving voltage and low power consumption can be provided. do. [Example]

[0350] In this example, a manufacturing example of a light-emitting element according to one embodiment of the present invention will be described. The optical element configuration is the same as that shown in Figure 1. The details of the element structure are shown in Table 5. The structures and abbreviations of the compounds are shown below. The structures and abbreviations of other compounds can be found in the previous examples. good.

[0351] [ka]

[0352] [Table 5]

[0353] <Fabrication of Light-Emitting Devices 3 to 6> The methods for fabricating the light-emitting elements 3 to 6 in this example are described below. The elements 3 to 6 are the same as the light-emitting element 1 shown above, except for the light-emitting layer 130 and the electron-transporting layer 118. Only the formation process was different, and the other processes were the same as those for the light-emitting element 1.

[0354] The light-emitting layer 130 of the light-emitting element 3 is made of 4,6mCzP2Pm and Ir(ppz)3. The weight ratio (4,6mCzP2Pm:Ir(ppz)3) was 1:0.1, and the thickness In the light-emitting layer 130, Ir(ppz)3 was first deposited by co-evaporation to a thickness of 40 nm. The first organic compound is 4,6mCzP2Pm, and the second organic compound is 4,6mCzP2Pm. 30, as an electron transport layer 118, 4,6mCzP2Pm was deposited to a thickness of 20 nm. and BPhen were deposited sequentially to a thickness of 10 nm.

[0355] The light-emitting layer 130 of the light-emitting element 4 is made of 9,9'-[pyrimidine-4,6-diylbis(bis(pyrimidine)] phenyl-3,3'-diyl)]bis(9H-carbazole) (abbreviation: 4,6mCzBP 2Pm) and Ir(ppz)3 in a weight ratio of 4,6mCzBP2Pm:Ir(ppz) 3) were co-deposited in a ratio of 1:0.1 to a thickness of 40 nm. In 30, Ir(ppz)3 is the first organic compound and 4,6mCzBP2Pm is Next, on the light-emitting layer 130, a layer of 4,6 m CzBP2Pm was mixed to a thickness of 20 nm and BPhen to a thickness of 10 nm. The layers were deposited sequentially.

[0356] The light-emitting layer 130 of the light-emitting element 5 is made of 5-methyl-4,6-bis[3-(9H-carbazo (5Me-4,6mCzP2Pm) and I r(ppz)3 and the weight ratio (5Me-4,6mCzP2Pm:Ir(ppz)3) is 1 The light-emitting layer 130 was co-deposited so that the thickness of the layer was 40 nm. In this study, Ir(ppz)3 was the first organic compound and 5Me-4,6mCzP2Pm was the second. Next, on the light-emitting layer 130, an electron transport layer 118 was formed using an organic compound of 5Me-4 ,6mCzP2Pm to a thickness of 20 nm, and BPhen to a thickness of 10 nm. The deposition was carried out sequentially so as to

[0357] The light-emitting layer 130 of the light-emitting element 6 is made of 4,4'-bis[3-(9H-carbazole-9- Ir (ppz)3, the weight ratio (4,4'mCzP2BPy:Ir(ppz)3) was 1:0. The light-emitting layer 130 was co-deposited to a thickness of 40 nm. Ir(ppz)3 is the first organic compound, and 4,4'mCzP2BPy is the second organic compound. Next, on the light-emitting layer 130, 4,4'mCzP2B Py was evaporated to a thickness of 20 nm, and then BPhen was evaporated to a thickness of 10 nm. I arrived.

[0358] <Light-emitting element characteristics> Next, the characteristics of the fabricated light-emitting elements 3 to 6 were measured. This is the same as Example 1.

[0359] FIG. 31 shows the luminance-current density characteristics of the light-emitting elements 3 to 6, and FIG. 32 shows the luminance-voltage characteristics of the light-emitting elements 3 to 6. The current efficiency vs. luminance characteristics are shown in Figure 33, the power efficiency vs. luminance characteristics in Figure 34, and the external quantum efficiency vs. luminance characteristics in Figure 35. The respective light-emitting elements 3 to 6 were subjected to a current of 2.5 mA / cm². m 2 The electroluminescence spectra when a current was passed through the electrodes at a current density of 1000 s is shown in FIG. Measurements were performed at room temperature (23°C).

[0360] Also, 1000cd / m 2 Table 6 shows the element characteristics of Light-emitting Elements 3 to 6 in the vicinity.

[0361] [Table 6]

[0362] As shown in FIG. 36, the electroluminescence spectra of light-emitting elements 3, 4, 5, and 6 showed peak wavelengths of 526 nm, 521 nm, 517 nm, and 50 8 nm, respectively, and full widths at half maximum of 95 nm, 96 nm, 100 nm, and 94 nm, indicating yellow emission. Although Ir(ppz)3 used in light-emitting elements 3 to 6 is known to emit blue light at low temperatures, the emission derived from Ir(ppz)3 was not measured.

[0363] Also, as shown in FIGS. 31 to 35 and Table 6, the light-emitting element 3 is driven at a low driving voltage, and the driving voltage is low in the order of light-emitting elements 3, 4, 5, and 6. Moreover, the light-emitting element 3 exhibits high luminous efficiency (current efficiency, power efficiency, and external quantum efficiency), and the luminous efficiency is high in the order of light-emitting elements 3, 4, 5, and 6.

[0364] <CV measurement results> Next, the electrochemical properties (oxidation reaction properties and reduction reaction properties) of the above compounds were measured by cyclic voltammetry (CV). The measurement method is the same as in Example 1. Also, the measurement results of 4,6mCzP2Pm and Ir(ppz)3 may be referred to the previous examples.

[0365] As a result of the CV measurement, the oxidation potential of 4,6mCzBP2Pm was 0.95 V and the reduction potential was -2. 14 V. Also, the HOMO level of 4,6mCzBP2Pm calculated from the CV measurement was -5.89 eV, and the LUMO level was -2.80 eV. From this, it was found that 4,6mCz BP2Pm has a low LUMO level.

[0366] As a result of CV measurement, the oxidation potential of 5Me-4,6mCzP2Pm was 0.97 V and the reduction potential was The H of 5Me-4,6mCzP2Pm calculated from the CV measurement was -2.22V. The OMO level was -5.91 eV and the LUMO level was -2.73 eV. 5Me-4,6mCzP2Pm was found to have a low-lying LUMO level.

[0367] The CV measurement showed that the oxidation potential of 4,4'mCzP2BPy was 1.00 V and the reduction potential was -2 The HOMO level of 4,4'mCzP2BPy calculated from the CV measurement was 0.29V. The LUMO level was -5.94 eV and the LUMO level was -2.66 eV. mCzP2BPy was found to have a low-lying LUMO level.

[0368] As described above, the second organic compounds 4,6mCzP2Pm and 4,6mCzBP2P The LUMO levels of m, 5Me-4,6mCzP2Pm, and 4,4'mCzP2BPy are The LUMO level of the first organic compound, Ir(ppz)3, is lower than that of the second organic compound. 4,6mCzP2Pm, 4,6mCzBP2Pm, 5Me-4,6mCzP2Pm, The HOMO levels of 4,4'mCzP2BPy and 4,4'mCzP2BPy are the same as those of the first organic compound, Ir(ppz )3. Therefore, as in the light-emitting elements 3 to 6, When these compounds are used, electrons and holes, which are carriers injected from a pair of electrodes, However, the second organic compound (4,6mCzP2Pm, 4,6mCzBP2Pm, 5M e-4,6mCzP2Pm, or 4,4'mCzP2BPy) and the first organic compound (I r(ppz)3), and the second organic compound (4,6mCzP2Pm, 4, 6mCzBP2Pm, 5Me-4,6mCzP2Pm, or 4,4'mCzP2BPy ) and the first organic compound (Ir(ppz)3) can form an exciplex.

[0369] In addition, the second organic compound (4,6mCzP2Pm, 4,6mCzBP2Pm, 5Me- 4,6mCzP2Pm or 4,4'mCzP2BPy) and the first organic compound (Ir( The exciplex formed with the second organic compound (4,6mCzP2Pm, 4, 6mCzBP2Pm, 5Me-4,6mCzP2Pm, or 4,4'mCzP2BPy ) and the HOMO level in the first organic compound (Ir(ppz)3). This results in an exciplex.

[0370] The energy of the LUMO level of 4,6mCzBP2Pm and the HOMO level of Ir(ppz)3 The energy difference is 2.59 eV. This value is the same as the electroluminescence spectrum of the light-emitting element 4 shown in FIG. This roughly coincides with the emission energy (2.38 eV) calculated from the peak wavelength of the torus. From this, the electroluminescence spectrum of the light-emitting element 4 is The emission is based on the exciplex formed by the reaction of ppz3. Since the difference between the S1 and T1 levels is small, the emission energy is The energy of 4,6mCzBP2Pm can be considered as 2.38 eV. The excited energy level of the exciplex formed with Ir(ppz)3 is 4,6mCzBP2P The energy difference between the LUMO level and the HOMO level of m (3.09 eV) is smaller than that. Therefore, by forming the exciplex, a light-emitting element with low driving voltage can be obtained.

[0371] In addition, the LUMO level of 5Me-4,6mCzP2Pm and the HOMO level of Ir(ppz)3 The energy difference between the potential is 2.66 eV. This value is the same as the potential of the light-emitting element 5 shown in FIG. The emission energy (2.40 eV) is roughly the same as that calculated from the peak wavelength of the field emission spectrum. From this, it can be seen that the electroluminescence spectrum of the light-emitting element 5 is It can be said that this emission is based on the exciplex formed by P2Pm and Ir(ppz)3. Since the difference between the S1 and T1 levels of an exciplex is small, the emission energy is The energy of the 5Me level can be considered to be the energy of the 1 level and the T1 level (2.40 eV). Excitation energy levels of the exciplex formed by -4,6mCzP2Pm and Ir(ppz)3 is the energy difference between the LUMO level and the HOMO level of 5Me-4,6mCzP2Pm (3 Therefore, by forming this exciplex, light emission with low driving voltage can be achieved. The element can be obtained.

[0372] In addition, the LUMO level of 4,4'mCzP2BPy and the HOMO level of Ir(ppz)3 The energy difference between these two is 2.73 eV. This value is the same as the electric field emission of the light-emitting element 6 shown in FIG. This roughly coincides with the emission energy (2.44 eV) calculated from the peak wavelength of the optical spectrum. From this, it can be seen that the electroluminescence spectrum of the light-emitting element 6 is The emission is based on the exciplex formed by Ir(ppz)3 and Ir(ppz). Since the difference between the S1 and T1 levels is small, the emission energy is and T1 level energy (2.44 eV). The excited energy level of the exciplex formed by P2BPy and Ir(ppz)3 is 4,4' Since the energy difference (3.28 eV) between the LUMO level and the HOMO level of mCzP2BPy is smaller, a light-emitting device with a low driving voltage can be obtained by forming the excimer.

[0373] Note that the compound used in the light-emitting device 3 is the same as the light-emitting device 2 shown in Example 2. That is, the electroluminescence spectrum of the light-emitting device 3 can be said to be emission based on the excimer formed by 4,6mCzP_{2}Pm and Ir(ppz)_{3}. Also, the emission energy can be regarded as the energy of the S1 level and the

[0374] <Measurement of the T1 level> Next, in order to obtain the T1 level of the compound used in the light-emitting layer 130, thin films of 4,6mCzBP_{2}Pm, 5Me-4,6mCzP_{2}Pm, and 4,4’mCzP _{2}BPy were respectively formed on a quartz substrate by vacuum evaporation, and the emission spectra of the thin films were measured at a low temperature (10 K). The

[0375] measurement method is the same as that in Example 1. The time-resolved spectra measured at low temperatures of 4,6mCzBP_{2}Pm, 5Me-4,6mCzP_{2}Pm, and 4,4’mCzP_{2}BPy are shown in FIGS. 37, 38, and 39, respectively.

[0376] From the results of the measured emission spectra, the wavelength of the peak on the shortest wavelength side (including the shoulder) of the phosphorescence component of the emission spectrum of 4,6mCzBP_{2}Pm was 452 nm. Also, the peak on the shortest wavelength side (including the shoulder) of the phosphorescence component of the The wavelength of the shortest wavelength peak (including the shoulder) of the phosphorescent component of the emission spectrum is 447 nm.

[0377] Therefore, from the above peak wavelength, the T1 level of 4,6mCzBP2Pm is 2.74 eV The T1 level of 5Me-4,6mCzP2Pm is 2.78 eV, and the T1 level of 4,4'mC The T1 level of zP2BPy was calculated to be 2.77 eV.

[0378] From the above measurement results, the T1 level (2.74 eV) of 4,6mCzBP2Pm is The T1 level of 4,6mCzBP2Pm is smaller than the T1 level of ppz3 (3.27 eV). (2.74 eV) is the exciplex formed by 4,6mCzBP2Pm and Ir(ppz)3 The T1 level (2.38 eV) of 4,6mCzBP2Pm is higher than that of 4,6mCzBP2Pm, and the LUMO level of 4,6mCzBP2Pm is higher than that of 4,6mCzBP2Pm. This is larger than the difference (2.59 eV) between the HOMO level of Ir(ppz)3. The exciplex formed by mCzBP2Pm and Ir(ppz)3 can emit light efficiently. Cut.

[0379] In addition, the T1 level (2.78 eV) of 5Me-4,6mCzP2Pm is Ir(ppz) The T1 level of 5Me-4,6mCzP2Pm ( 2.78 eV) is the excitation formed by 5Me-4,6mCzP2Pm and Ir(ppz)3 The T1 level of the complex (2.40 eV) is larger than that of the 5Me-4,6mCzP2Pm. The difference between the HOMO level of Ir(ppz)3 and the HOMO level of Ir(ppz)3 (2.66 eV) is larger than that. Therefore, the exciplex formed by 5Me-4,6mCzP2Pm and Ir(ppz)3 is efficiently It can emit light.

[0380] In addition, the T1 level (2.77 eV) of 4,4'mCzP2BPy is The T1 level (3.27 eV) is smaller than that of 4,4'mCzP2BPy (2.77 eV). eV) is the T1 level of the exciplex formed by 4,4'mCzP2BPy and Ir(ppz)3. The LUMO level of 4,4'mCzP2BPy is higher than that of Ir(p pz)3 HOMO level difference (2.73 eV). The triplet excitation energy of the exciplex formed by CzP2BPy and Ir(ppz)3 is 4 ,4'mCzP2BPyT1 level, and the exciplex emits efficiently. In addition, it is difficult to emit light on the short wavelength side of the electroluminescence spectrum of the light-emitting element 6 shown in FIG. The wavelength of the rising edge corresponds to the T1 level (2.77 eV) of 4,4'mCzP2BPy. This wavelength is shorter than the wavelength (448 nm). This allows the exciplex to emit light efficiently. In this case, the T1 level of the compound that forms the exciplex is on the short wavelength side of the emission spectrum of the exciplex. It is preferable that the energy is higher than the energy converted from the wavelength of the rising edge.

[0381] In addition, from the above results, it was found that the lower T1 level of the first organic compound and the second organic compound and the T1 level of the exciplex formed by the first organic compound and the second organic compound. The larger the energy difference, the more preferable. Specifically, The lower T1 level is the exciplex formed by the first organic compound and the second organic compound. It is preferable that the T1 level is 0.35 eV or more higher. The T1 level of one of the first organic compound and the second organic compound, which has a lower T1 level, is The difference in energy between the lower LUMO level and the upper HOMO level of the second organic compound is The larger the energy difference, the more preferable. Specifically, The T1 level of one of the first and second organic compounds is lower than the T1 level of the other of the first and second organic compounds. The difference between the lower LUMO level and the upper HOMO level must be at least 0.1 eV larger. This can be said to be desirable.

[0382] When the emission spectrum of Ir(ppz)3 was measured at room temperature, In Non-Patent Document 1, the luminescence quantum yield of Ir(ppz)3 is It is reported that the solubility of Ir(ppz)3 is less than 1% at room temperature. It is clear that the material does not emit light.

[0383] On the other hand, the light-emitting elements 3 to 6 contain the second organic compound (4,6mCzP2Pm, 4, 6mCzBP2Pm, 5Me-4,6mCzP2Pm, or 4,4'mCzP2BPy ) and the first organic compound (Ir(ppz)3) The reason why light is emitted from the light-emitting elements 3 to 6 is that the pair of electrodes The electrons originate from singlet excitons generated by the recombination of injected carriers (holes and electrons). In addition to the emission from triplet excitons, there is also emission from reverse intersystem crossing in exciplexes. This is because light emission originating from singlet excitons generated from triplet excitons is obtained. That is, according to one embodiment of the present invention, even when a compound having a low luminescence quantum yield of less than 1% is used, Even if the amount of the fluorine-containing compound is small, a light-emitting element having high luminous efficiency can be obtained.

[0384] 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 with low driving voltage and low power consumption can be provided. do. [Example]

[0385] In this example, a manufacturing example of a light-emitting element according to one embodiment of the present invention will be described. The optical element configuration is the same as that shown in Figure 1. The details of the element structure are shown in Table 7. The structures and abbreviations of the compounds are shown below. For the structures and abbreviations of other compounds, please refer to Example 2. That's fine.

[0386] [ka]

[0387] [Table 7]

[0388] <Fabrication of Light-Emitting Devices 7 and 8> The method for fabricating the light-emitting elements 7 and 8 in this example will be described below. The light-emitting element 8 differs from the light-emitting element 1 described above only in the process of forming the light-emitting layer 130. The steps were the same as those for the light-emitting element 1.

[0389] The light-emitting layer 130 of the light-emitting element 7 is made of 4,6mCzP2Pm and fac-tris(1-furan). Phenyl-3-methylbenzimidazolin-2-ylidene-C,C 2 ') Iridium (II I) (abbreviation: fac-Ir(pmb)3) and a weight ratio of (4,6mCzP2Pm:fac -Ir(pmb)3) was co-evaporated to a thickness of 40 nm. In the light-emitting layer 130, fac-Ir(pmb)3 is the first organic compound, 4,6mCzP2Pm is the second organic compound.

[0390] The light-emitting layer 130 of the light-emitting element 8 is made of 4,6mCzP2Pm and mer-tris(1-furan). Phenyl-3-methylbenzimidazolin-2-ylidene-C,C 2 ') Iridium (II I) (abbreviation: mer-Ir(pmb)3) and a weight ratio of (4.6mCzP2Pm:mer -Ir(pmb)3) was co-evaporated to a thickness of 40 nm. In the light-emitting layer 130, mer-Ir(pmb)3 is the first organic compound, 4,6mCzP2Pm is the second organic compound.

[0391] <Light-emitting element characteristics> Next, the characteristics of the fabricated light-emitting elements 7 and 8 were measured. This is the same as Example 1.

[0392] The luminance-current density characteristics of the light-emitting elements 7 and 8 are shown in FIG. 40, and the luminance-voltage characteristics are shown in FIG. 41. The current efficiency vs. luminance characteristics are shown in Figure 42, the power efficiency vs. luminance characteristics in Figure 43, and the external quantum efficiency vs. luminance characteristics in Figure 44. The respective light-emitting elements 7 and 8 have the same luminance characteristics as those of the light-emitting elements 7 and 8, respectively. mA / cm 2 The electroluminescence spectrum when a current was passed at a current density of 1000 kJ / s is shown in FIG. Measurement of each light-emitting device was carried out at room temperature (in an atmosphere maintained at 23°C).

[0393] Also, 1000 cd / m 2 The device characteristics of the light-emitting elements 7 and 8 in the vicinity are shown in Table 8. Shown below.

[0394] [Table 8]

[0395] As shown in FIG. 45, the electroluminescence spectra of the light-emitting element 7 and the light-emitting element 8 have peak wavelengths of 536 nm and 551 nm, respectively, and the full width at half maximum is 106 nm and 109 nm, showing broad yellow light emission. Note that fac-Ir(p mb)3 and mer-Ir(pmb)3 used in the light-emitting element 7 and the light-emitting element 8 are compounds that emit blue light as shown later However, no emission derived from fac-Ir(pmb)3 and mer-Ir(pmb)3 was observed from the light-emitting elements 7 and 8. from which

[0396] Also, as shown in FIGS. 40 to 44 and Table 8, the light-emitting element 7 and the light-emitting element 8 are driven at a low driving voltage. Further, the light-emitting element 7 and the light-emitting element 8 exhibit high luminous efficiency (current efficiency , power efficiency, and external quantum efficiency). Therefore, the light-emitting element of one aspect of the present invention having the first organic compound (fac -Ir(pmb)3 or mer-Ir(pmb)3) and the second organic compound (4,6m CzP2Pm) has a low driving voltage, high luminous efficiency , and low power consumption.

[0397] <CV measurement results> Next, the electrochemical properties (oxidation reaction properties and reduction reaction properties) of the above compounds were measured by cyclic voltammetry (CV) measurement. The measurement method is the same as that in Example 1 .

[0398] As a result of the CV measurement, the oxidation potential of fac-Ir(pmb)3 was 0.55 V. Also, the HOMO level of fac-Ir(pmb)3 calculated from the CV measurement was -5.49 eV This indicates that fac-Ir(pmb)3 has a high HOMO level. The oxidation potential of mer-Ir(pmb)3 was 0.38 V. The HOMO level of mer-Ir(pmb)3 calculated from the measurement was -5.32 eV. This indicates that mer-Ir(pmb)3 has a high HOMO level. The reduction potentials of fac-Ir(pmb)3 and mer-Ir(pmb)3 are low and clear. Since no reduction peak was observed, it was confirmed that fac-Ir(pmb)3 and mer-Ir( pmb)3 is predicted to have a high LUMO level.

[0399] As described above, the LUMO level of the second organic compound, 4,6mCzP2Pm, is The LUMO of the organic compounds fac-Ir(pmb)3 and mer-Ir(pmb)3 The HOMO level of the second organic compound, 4,6mCzP2Pm, is lower than that of the first The HOMO states of the organic compounds fac-Ir(pmb)3 and mer-Ir(pmb)3 Therefore, as in the light-emitting devices 7 and 8, when these compounds are added to the light-emitting layer, When a semiconductor device is used, electrons and holes, which are carriers injected from a pair of electrodes, are efficiently transported to the second The first organic compound (4,6mCzP2Pm) and the second organic compound (fac-Ir(pmb)3 or mer-Ir(pmb)3), respectively, and a second organic compound (4,6mC zP2Pm) and the first organic compound (fac-Ir(pmb)3 or mer-Ir(pm b) It can form an exciplex with 3).

[0400] In addition, the second organic compound (4,6mCzP2Pm) and the first organic compound (fac-Ir The exciplex formed with Ir(pmb)3 or mer-Ir(pmb)3 is The first organic compound (fac-Ir It becomes an exciplex with a HOMO level in (pmb)3 or mer-Ir(pmb)3). .

[0401] 4,6mThe LUMO level of CzP2Pm and the HOMO level of fac-Ir(pmb)3 The energy difference is 2.61 eV. This value is the same as the electroluminescence of the light-emitting element 7 shown in FIG. This roughly coincides with the emission energy (2.31 eV) calculated from the peak wavelength of the spectrum. From this, it can be seen that the electroluminescence spectrum of the light-emitting element 7 is composed of 4,6mCzP2Pm and f This can be said to be the emission based on the exciplex formed by ac-Ir(pmb)3. Since the difference between the S1 level and the T1 level is small, the emission energy is and the energy of the T1 level (2.31 eV). The excited energy level of the exciplex formed by P2Pm and fac-Ir(pmb)3 is 4 The energy difference between the LUMO and HOMO levels of 6mCzP2Pm (3.01 eV) Therefore, by forming the exciplex, a light-emitting element with a low driving voltage can be obtained. can be done.

[0402] In addition, the LUMO level of 4,6mCzP2Pm and the HOMO level of mer-Ir(pmb)3 The energy difference between the potential is 2.44 eV. This value is the same as the potential of the light-emitting element 8 shown in FIG. The emission energy (2.25 eV) is roughly the same as that calculated from the peak wavelength of the field emission spectrum. From this, it can be seen that the electroluminescence spectrum of the light-emitting element 8 is 4,6mCzP2Pm It can be said that the emission is based on the exciplex formed by mer-Ir(pmb)3 and mer-Ir(pmb). Since the difference between the S1 and T1 levels of an exciplex is small, the emission energy is The energy of the 1 and T1 levels (2.25 eV) can be considered as the energy of the 4,6 Excitation energy levels of the exciplex formed by mCzP2Pm and mer-Ir(pmb)3 is the energy difference between the LUMO level and the HOMO level of 4,6mCzP2Pm (3.01e Therefore, by forming the exciplex, a light-emitting element with a low driving voltage can be obtained. It is possible.

[0403] <Absorption and emission spectra of compounds> Next, the absorption spectra of fac-Ir(pmb)3 and mer-Ir(pmb)3 and The results of measuring the emission spectrum are shown in FIG.

[0404] To measure the absorption and emission spectra, fac-Ir(pmb)3 or A dichloromethane solution containing mer-Ir(pmb)3 was prepared and measured using a quartz cell. The absorption spectrum was measured using an ultraviolet-visible spectrophotometer (JASCO Corporation). From the measured spectrum of the solution, the quartz cell and dichloromethane were used. The absorption spectrum of methyl methacrylate was subtracted. The emission spectrum was measured using a PL-EL spectrometer. The solution was measured using a chromatograph (manufactured by Hamamatsu Photonics). It was conducted in a humid atmosphere.

[0405] As shown in Figure 46, the absorption of fac-Ir(pmb)3 and mer-Ir(pmb)3 The lowest energy (longest wavelength) absorption edge in the spectrum is around 380 nm. In addition, the absorption edge is calculated from the absorption spectrum data, and the transition energy assuming a direct transition is calculated. As a result of estimating the transition energy of fac-Ir(pmb)3 and mer-Ir(pmb)3, The energies were calculated to be 3.20 eV and 3.15 eV. Since mer-Ir(pmb)3 is a phosphorescent compound, the lowest energy absorption band is This absorption band is based on the transition to the triplet excited state. Therefore, fac-Ir(pmb)3 The T1 levels of mer-Ir(pmb)3 are calculated to be 3.20 eV and 3.15 eV. .

[0406] From the above measurement results, the T1 level (2.70 eV) of 4,6mCzP2Pm is fac- The T1 level of 4,6mCzP2Pm is smaller than that of Ir(pmb)3 (3.20 eV). The level (2.70 eV) is formed by 4,6mCzP2Pm and fac-Ir(pmb)3. The T1 level (2.31 eV) of the exciplex is larger than that of the exciplex, and the LUM of 4,6mCzP2Pm This is larger than the difference between the O level and the HOMO level of fac-Ir(pmb)3 (2.61 eV). Therefore, the exciplex formed by 4,6mCzP2Pm and fac-Ir(pmb)3 is effective. It can emit light efficiently.

[0407] In addition, the T1 level (2.70 eV) of 4,6mCzP2Pm is mer-Ir(pmb) It is smaller than the T1 level of 3 (3.15 eV) and the T1 level of 4,6mCzP2Pm (2.70 eV). eV) is the T of the exciplex formed by 4,6mCzP2Pm and mer-Ir(pmb)3 1 level (2.25 eV), and is closer to the LUMO level of 4,6mCzP2Pm than -Ir(pmb)3 HOMO level difference (2.44 eV) is larger. The exciplex formed by 6mCzP2Pm and mer-Ir(pmb)3 emits efficiently. It is possible.

[0408] Furthermore, the light-emitting element 8 has higher efficiency than the light-emitting element 7 and is driven at a lower driving voltage. Therefore, the lower T1 level of the first organic compound and the lower T1 level of the second organic compound and the lower T1 level of the first organic compound are The energy difference between the T1 level of the exciplex formed by the compound and the second organic compound is large. Specifically, the lower T1 of the first organic compound and the second organic compound is preferable. The level is 0 from the T1 level of the exciplex formed by the first organic compound and the second organic compound. It is preferable that the first organic compound and the second organic compound have a larger value than the first organic compound. The T1 level of one of the compounds having a lower T1 level and the T1 level of the first organic compound and the T1 level of the second organic compound The energy difference between the lower LUMO level and the higher HOMO level is large. Specifically, it is preferable that the first organic compound and the second organic compound have a lower T1 level. The other T1 level is the lower LUMO level of the first organic compound and the second organic compound. It is preferable that the difference between the HOMO level and the higher HOMO level is 0.1 eV or more. .

[0409] In addition, Non-Patent Document 1 states that the luminescence quantum yield of fac-Ir(pmb)3 is 37% at room temperature. Therefore, fac-Ir(pmb)3 is suitable as a light-emitting material. It can be seen that the material has a low luminescence quantum yield.

[0410] On the other hand, the light-emitting elements 7 and 8 contain a second organic compound (4,6mCzP2Pm) and a third organic compound (4,6mCzP2Pm). Formed with organic compound 1 (fac-Ir(pmb)3 or mer-Ir(pmb)3) The light-emitting elements 7 and 8 exhibit light emission derived from an exciplex. The reason why the light-emitting elements 7 and 8 have good device characteristics is that the light-emitting elements 7 and 8 are injected from a pair of electrodes. The emission is due to singlet excitons generated by the recombination of injected carriers (holes and electrons). In addition to light, emission from triplet excitons or reverse intersystem crossing in exciplexes This is because light emission originates from singlet excitons generated from triplet excitons. That is, according to one embodiment of the present invention, even when a compound with a low luminescence quantum yield is used, a high luminescence quantum yield can be obtained. A light-emitting element having high luminous efficiency can be obtained.

[0411] 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 with low driving voltage and low power consumption can be provided. do. [Example]

[0412] In this example, a light-emitting element 3, which is a light-emitting element of one embodiment of the present invention, and a comparative light-emitting element 9 were fabricated. Comparative light-emitting element 9 has a triplet structure as a combination for forming an exciplex in the light-emitting layer. A combination of host materials that does not have the function of converting excitation energy into luminescence was used. The structure of the light-emitting device fabricated in this example is the same as that shown in Figure 1. Details of the device structure are shown in Table 9. The structures and abbreviations of the compounds used are shown below. The structures and abbreviations of other compounds are as follows: Please refer to the examples.

[0413] [ka]

[0414] [Table 9]

[0415] <Fabrication of Comparative 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).

[0416] 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 co-deposition was carried out so that the thickness was 40 nm.

[0417] Next, on the hole injection layer 111, 4-phenyl-4'-(9-phenyl-4'-phenyl)- (phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP) The deposition was carried out so that the thickness was nm.

[0418] Next, a light-emitting layer 130 containing 4,6mCzP2Pm and N-(4 -biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl Benzyl-9H-carbazol-3-amine (abbreviation: PCBiF) and The ratio of P2Pm:PCBiF was set to 0.8:0.2 and the thickness was set to 40 nm. was co-evaporated onto

[0419] Next, on the light-emitting layer 130, 4,6mCzP2Pm was deposited to a thickness of 2 0 nm, and 2,9-bis(naphthalen-2-yl)-4,7-diphenyl- 1,10-phenanthroline (abbreviation: NBPhen) was deposited in order to make the thickness 15 nm. Next, LiF was deposited on the electron transport layer 118 to form the electron injection layer 119. The vapor deposition was carried out so that the thickness became m.

[0420] 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.

[0421] Next, in a glove box with a nitrogen atmosphere, a glass substrate for sealing is attached to an organic By using an EL sealant to fix the organic material to the glass substrate, the electrodes and EL Specifically, a sealant was applied around the organic material formed on the glass substrate. The glass substrate and a glass substrate for sealing are bonded together, and ultraviolet light having a wavelength of 365 nm is applied. 6J / cm 2 The light-emitting element was irradiated with light and then heat-treated at 80° C. for 1 hour. obtained.

[0422] <Light-emitting element characteristics> Next, the characteristics of the fabricated light-emitting element 3 and the comparative light-emitting element 9 were measured. is the same as in the first embodiment.

[0423] FIG. 47 shows the external quantum efficiency vs. luminance characteristics of the light-emitting element 3 and the comparative light-emitting element 9. The light emitting element 3 and the comparative light emitting element 9 were each 2.5 mA / cm 2 A current was passed at a current density of The electroluminescence spectrum at this time is shown in Figure 48. The measurements for each light-emitting element were kept at room temperature (23°C). The event was held in a relaxed atmosphere.

[0424] Also, 1000cd / m 2 The element characteristics of the light-emitting element 3 and the comparative light-emitting element 9 in the vicinity Shown in Table 10.

[0425] [Table 10]

[0426] As shown in FIG. 48, the electroluminescence spectra of the light-emitting element 3 and the comparative light-emitting element 9 have peaks The wavelengths are 526 nm and 548 nm, respectively, and the full width at half maximum is 95 nm and 91 nm. As mentioned above, the light emitted from the light-emitting element 3 was 4,6mCzP This is the emission from the exciplex of 2Pm and Ir(ppz)3.

[0427] The emission energy calculated from the peak wavelength of the emission obtained from the comparative light-emitting element 9 is 2.26 eV. This is calculated from CV measurements using the method described in Example 1. The LUMO level of Pm is -2.88 eV and the HOMO level of PCBiF is -5.26 eV. This roughly coincides with the energy difference of 2.38 eV obtained from the comparative light-emitting element 9. The light emission originates from the exciplex formed between 4,6mCzP2Pm and PCBiF in the emissive layer. It can be said to be luminescence.

[0428] 47 and Table 10, the light-emitting element 3 has a higher external quantum efficiency than the comparative light-emitting element 9. This is because the light-emitting element 3 has a compound that forms an exciplex. This is because a compound having a heavy atom is used. Therefore, a high-performance light-emitting element can be provided.

[0429] <Quantum yield measurement of thin films> Next, the mixed film of 4,6mCzP2Pm and Ir(ppz)3 used in the light-emitting layer of light-emitting element 3 The quantum yield was measured. The measurement sample was a quartz substrate coated with 4,6mCzP2Pm and Ir(ppz )3 in a weight ratio (4,6mCzP2Pm:Ir(ppz)3) of 1:0.1 The deposition was carried out in a nitrogen atmosphere glove box to prevent exposure to the atmosphere. The measurement was carried out using an absolute PL quantum yield measurement device (Hamamatsu Photonics C1 1347-01) was used and measured at room temperature.

[0430] As a result, the quantum yield of the mixed film of 4,6mCzP2Pm and Ir(ppz)3 was 64%. Considering that the light extraction efficiency of glass is about 30%, the external quantum efficiency of Light-emitting Device 3 is 19%. From Figure 47, the maximum external quantum efficiency of Light-emitting Device 3 is estimated to be 19. 7%, and the quantum yield measurement results for the mixed film of 4,6mCzP2Pm and Ir(ppz)3 This is in agreement with the estimate of 4,6m The quantum efficiency of the mixed film of CzP2Pm and Ir(ppz)3 is the major factor. Therefore, the generated excitons are not only singlet excitons but also triplet excitons. This is because one of the compounds forming the exciplex has a heavy atom. This is presumably because a compound having a hydroxyl group is used.

[0431] <Transient EL measurement of thin films> Next, transient EL measurements were carried out on the light-emitting element 3 and the comparative light-emitting element 9. The measurements were carried out using picosecond fluorescence lifetime A measurement system (manufactured by Hamamatsu Photonics) was used. To measure the lifetime, a rectangular pulse voltage is applied to the light emitting element, and the decay time is measured from the fall of the voltage. The luminescence was measured by a streak camera with a time resolution. By applying the voltage and integrating the data measured repeatedly, data with a high S / N ratio was obtained. The measurements were carried out at room temperature (300K), with an applied pulse voltage of around 3V and a pulse duration of 1 00μsec, negative bias voltage is -5V, measurement time range is 20μsec for light-emitting element 3, The test was performed under the condition of 50 μsec for comparative light emitting element 9. The results are shown in FIG.

[0432] As can be seen from FIG. 49, the comparative light-emitting element 9 has a large amount of delayed fluorescent components and an extremely long emission lifetime. Although the light-emitting element 3 does not have many delay components, as shown in FIG. 47, the external quantum efficiency is higher than that of the comparative light-emitting element 9. Also, as shown in Figure 49, the emission lifetime is very short. This is because the excitation state This indicates that the luminescent element with such a short luminescence lifetime decays from the luminescent state to the ground state in a short time. Children are preferred because they are more reliable.

[0433] The light-emitting element 3 contains Ir, which is a heavy atom, in the material that forms the exciplex. This is thought to be a different behavior from that of exciplexes and TADF materials using host materials. .

[0434] 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 with high reliability can be provided. [Explanation of symbols]

[0435] 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 Lighting Unit 108 Lighting 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 luminescent layer 130 Light-emitting layer 131 compounds 132 compounds 133 Compound 140 Light-emitting layer 140a Light-emitting layer 140b Light-emitting layer 145 Bulkhead 150 light-emitting elements 200 boards 220 board 221B area 221G area 221R area 222B area 222G area 222R area 223 Light blocking layer 224B Optical Elements 224G Optical Element 224R Optical Element 250 light-emitting elements 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 8000 Display Module 8001 Top cover 8002 Lower cover 8003 FPC 8004 Touch Sensor 8005 FPC 8006 Display device 8009 Frame 8010 Printed Circuit Board 8011 Battery 8501 Lighting equipment 8502 Lighting equipment 8503 Lighting equipment 8504 Lighting equipment 9000 chassis 9001 Display section 9003 Speaker 9005 Operation key 9006 Connection terminal 9007 Sensor 9008 Microphone 9050 Operation button 9051 Information 9052 Information 9053 Information 9054 Information 9055 Hinge 9100 Mobile Information Terminal 9101 Mobile Information Terminal 9102 Mobile Information Terminal 9200 Mobile Information Terminal 9201 Mobile Information Terminal

Claims

[Claim 1] A light-emitting element having a light-emitting layer, the light-emitting layer includes a first organic compound and a second organic compound; a LUMO level of one of the first organic compound and the second organic compound is equal to or higher than a LUMO level of the other of the first organic compound and the second organic compound; a HOMO level of one of the first organic compound and the second organic compound is equal to or higher than a HOMO level of the other of the first organic compound and the second organic compound; the first organic compound and the second organic compound form an exciplex, the first organic compound has a function of not exhibiting fluorescence but being able to exhibit phosphorescence, the first organic compound has a luminescence quantum yield of 0% or more and 40% or less at room temperature; The light-emitting element, wherein the light emitted from the light-emitting layer includes light emitted from the exciplex.

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