Light-emitting device

Abstract

To provide an electronic device having high light extraction efficiency or light trapping effect.SOLUTION: An electronic device has a first layer and a second layer between a first electrode and a second electrode, and the first layer between the first electrode and the second layer, the first layer has a first organic compound and a first substance, the refractive index of the thin film of the first organic compound is 1 or more and 1.75 or less, the first substance has electron-accepting properties, and the second layer has a function of emitting or absorbing light.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] One aspect of the present invention relates to a novel electronic device. The present invention relates to an electronic device using the same, or a light-emitting device, an electronic device, and Regarding lighting devices.

[0002] Note that one aspect of the present invention is not limited to the above technical fields. The present invention relates to a process, a machine, a manufacturing method, In particular, one aspect of the present invention relates to a composition of matter. , electronic devices, semiconductor devices, light-emitting devices, display devices, lighting devices, light-emitting elements, and their manufacture It concerns the method. [Background technology]

[0003] Electroluminescence (EL) using organic compounds Electronic devices such as light-emitting elements (organic electroluminescence elements) and organic solar cells that use The basic structure of these electronic devices is a pair of electrodes sandwiched between two organic compounds. A semiconductor layer containing

[0004] Such electronic devices are lightweight, flexible, and highly designable. Coating processes are possible, etc. Since it has various advantages, research and development of it is being actively carried out. Therefore, when used as display pixels, they have high visibility and do not require a backlight. These advantages make the film suitable for use as a flat panel display element.

[0005] Such electronic devices mainly have an organic semiconductor layer formed by thinning organic compounds. Since the organic compound and layer structure have a significant effect on the organic semiconductor element, The selection of the layer structure is important. In addition, the organic solar cell and the organic electroluminescence element emit light. In electronic devices that absorb light, structures with high light extraction efficiency and light trapping effect are important. It is essential.

[0006] Various methods have been proposed to improve the light extraction efficiency of organic EL elements. For example, Patent Document 1 The light extraction efficiency is improved by creating an uneven shape in part of the electrodes and EL layer. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2013-033706 A Summary of the Invention [Problem to be solved by the invention]

[0008] In light-emitting devices such as organic EL devices, the light extraction efficiency can be improved by using a substrate. There are ways to adjust the refractive index between the plate and the electrode and / or between the electrode and the EL layer. However, when a layer for adjusting the refractive index is introduced into an organic EL device, the process becomes complicated. Therefore, there is a need to develop a layer and layer structure that can control the refractive index while retaining the function of an EL layer. In addition, there is a demand for the development of layers and layer structures with high light trapping effects in organic solar cells. It is being considered.

[0009] In view of the above-mentioned problems, one aspect of the present invention is to provide an electronic device having high light extraction efficiency. Another object of the present invention is to provide an electronic device including a layer having a low refractive index. Another object of the present invention is to provide an electronic device having a low driving voltage. Another object of one embodiment of the present invention is to provide an electronic device with reduced power consumption. Another object of the present invention is to provide a highly reliable electronic device. Another object of the present invention is to provide an electronic device with high light emission efficiency. Another object of the present invention is to provide a novel electronic device. Another object of the present invention is to provide an electronic device having a high light trapping effect. Another object of the present invention is to provide a novel semiconductor device. The objective of the project is to provide

[0010] Note that the above description of the object does not preclude the existence of other objects. However, it is not necessary to solve all of these problems. Problems other than those mentioned above may be solved by the description of the specification, etc. It is obvious from the description of the specification that other problems can be extracted. . [Means for solving the problem]

[0011] One embodiment of the present invention is a semiconductor device having a first layer and a second layer between a first electrode and a second electrode. The first layer is disposed between the electrode and the second layer, and the first layer contains a first organic compound and a first substance. The thin film of the first organic compound has a refractive index of 1 or more and 1.75 or less, and the first material is an electron The first layer is an electronic device that has the function of receiving light and the second layer has the function of emitting or absorbing light. .

[0012] In addition, another embodiment of the present invention is a semiconductor device having a first layer between a first electrode and a second electrode, The layer has a first organic compound and a first material, the first organic compound being in contact with a first backbone and an electron donating The first skeleton is a tetraarylmethane skeleton or a tetraarylsilane skeleton. It is an electronic device.

[0013] In the above-mentioned structure, the refractive index of the first layer is preferably 1 or more and 1.75 or less. This can improve the light extraction efficiency and light trapping effect of the electronic device.

[0014] In the above structure, the compound having a tetraarylmethane skeleton and a tetraarylsilane skeleton is Each of the aryl groups is independently a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. It is more preferable that the aryl group is a substituted or unsubstituted phenyl group. By using this structure, it is possible to obtain an organic compound having a low refractive index and good carrier transport properties. The aryl groups or phenyl groups may be bonded to each other to form a ring.

[0015] In the above structure, the electron donating skeleton is a pyrrole skeleton, an aromatic amine skeleton, an acridine skeleton, It is preferable that the compound contains either one of an azepine skeleton and an azepine skeleton. The driving voltage of the child device can be reduced.

[0016] In the above-mentioned structure, the glass transition point (Tg) of the first organic compound is 100° C. or higher. By adopting this configuration, an electronic device having excellent heat resistance can be obtained.

[0017] In the above structure, the refractive index of the first layer is preferably lower than the refractive index of the second layer. This configuration can improve the light extraction efficiency and light trapping effect of electronic devices. can.

[0018] In another aspect of the present invention, a first layer, a second layer, and a second layer are provided between a first electrode and a second electrode. The first layer is disposed between the first electrode and the second layer, and the third layer is disposed between the first layer and the third layer. The first layer has a first organic compound and a first substance, and the second layer has a first organic compound and a first substance. The refractive index of the thin film of the material is 1 or more and 1.75 or less, the first material has an electron accepting property, and the third The layers have the function of emitting or absorbing light, and the refractive index of the first layer is lower than the refractive index of the second layer. The refractive index of the first layer is lower than the refractive index of the third layer.

[0019] In the above-mentioned structure, it is preferable that the first organic compound has an electron donating property. By doing so, it is possible to obtain an electronic device having good carrier transport properties.

[0020] In the above structure, it is preferable that the first layer and the second layer are in contact with each other, and the second layer and the third layer are in contact with each other. It is more preferable that the layers are in contact with each other. By adopting such a configuration, the refractive index difference between the layers can be suppressed. This can improve the light extraction efficiency and light trapping effect of electronic devices.

[0021] In the above structure, the refractive index of the first layer is preferably lower than the refractive index of the first electrode. This configuration can improve the light extraction efficiency and light trapping effect of electronic devices. can.

[0022] In the above-mentioned structure, the volume ratio of the first substance in the first layer is a first organic compound. With this configuration, the electronic device This can improve the light extraction efficiency and light trapping effect of the semiconductor laser.

[0023] In the above structure, the first substance is titanium oxide, vanadium oxide, or tantalum oxide. oxide, molybdenum oxide, tungsten oxide, rhenium oxide, ruthenium oxide, chromium oxide It is preferable that the oxide contains any one of aluminum oxide, zirconium oxide, hafnium oxide, and silver oxide. By adopting this structure, it is possible to obtain an electronic device having a good carrier transport property.

[0024] In the above configuration, the first substance is 7,7,8,8-tetracyanoquinodimethane (abbreviated Name: TCNQ), 7,7,8,8-tetracyano-2,3,5,6-tetrafluoro- Nodimethane (abbreviation: F4TCNQ) and 1,3,4,5,7,8-hexafluorotetrafluoroethylene It is preferable that the compound is any one of cyano-naphthoquinodimethane (abbreviation: F6TCNNQ). With this structure, an electronic device having good carrier transport properties can be obtained.

[0025] In the above-mentioned configuration, it is preferable that the electronic device is an organic EL element or a solar cell. .

[0026] Another embodiment of the present invention is a light-emitting element having the above structure and at least one housing or a touch sensor. Another embodiment of the present invention is an electronic device having any of the above-described structures. A lighting device having a device and at least one of a housing, a connection terminal, and a protective cover. Further, one embodiment of the present invention is not only a light-emitting device having an electronic device, but also a light-emitting device having a light-emitting device. Therefore, the term "light-emitting device" in this specification includes electronic devices that display images. It also refers to a light source (including lighting equipment). C (Flexible Printed Circuit), TCP (Tape Car) Display module with a printer package attached, and a printed circuit board at the end of the TCP. Display module with a wiring board or electronic device with COG (Chip On Glass) A display module in which an IC (integrated circuit) is directly mounted by the assembling method is also an embodiment of the present invention. It is. Effect of the Invention

[0027] According to one embodiment of the present invention, an electronic device with high light extraction efficiency can be provided. According to one aspect of the present invention, an electronic device including a layer having a low refractive index can be provided. Alternatively, according to one embodiment of the present invention, an electronic device with a low driving voltage can be provided. According to one embodiment of the present invention, an electronic device with reduced power consumption can be provided. According to one embodiment of the present invention, a highly reliable electronic device can be provided. According to one embodiment of the present invention, an electronic device with high light emission efficiency can be provided. Alternatively, according to one aspect of the present invention, a novel electronic device can be provided. Alternatively, an electronic device having a high light trapping effect can be provided according to one embodiment of the present invention. According to one embodiment of the present invention, a novel semiconductor device can be provided. can.

[0028] Note that the description of these effects does not preclude the existence of other effects. It is not necessary to have all of these effects. Effects other than these are described in the specification. The disclosure of the specification, drawings, claims, etc. is self-evident, and the disclosure of the specification, drawings, claims, etc. is self-evident. From this, it is possible to extract other effects. [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 is a schematic cross-sectional view of an electronic device according to one embodiment of the present invention. [Diagram 2] 1A and 1B are a schematic cross-sectional view and a diagram illustrating an optical path length of a light-emitting element of one embodiment of the present invention. [Diagram 3] 1A and 1B are schematic cross-sectional views of a light-emitting element of one embodiment of the present invention and a diagram illustrating the correlation between energy levels of a light-emitting layer. [Figure 4] 1A and 1B are schematic cross-sectional views of a light-emitting element of one embodiment of the present invention and a diagram illustrating the correlation between energy levels of a light-emitting layer. [Diagram 5] FIG. 1 is a conceptual diagram of an active matrix light-emitting device according to one embodiment of the present invention. [Figure 6] FIG. 1 is a conceptual diagram of an active matrix light-emitting device according to one embodiment of the present invention. [Figure 7] FIG. 1 is a conceptual diagram of an active matrix light-emitting device according to one embodiment of the present invention. [Figure 8] 1 is a schematic diagram of an electronic device according to one embodiment of the present invention. [Figure 9] 1 is a schematic diagram of an electronic device according to one embodiment of the present invention. [Figure 10] 1 illustrates a lighting device according to one embodiment of the present invention. [Figure 11] 1 illustrates a lighting device according to one embodiment of the present invention. [Figure 12] FIG. 4 is a diagram for explaining refractive index in the embodiment. [Figure 13] FIG. 13 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 14] FIG. 13 is a graph showing current density-voltage characteristics of a light-emitting element in the example. [Figure 15] FIG. 13 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Figure 16] FIG. 4 is a diagram illustrating an emission spectrum in the example. [Figure 17] FIG. 2 is a graph showing the external quantum efficiency vs. chromaticity x characteristics of a light-emitting element according to an embodiment. [Figure 18] FIG. 13 is a diagram illustrating the relationship between the external quantum efficiency and the volume ratio of MoO3 in the embodiment. [Figure 19]FIG. 4 is a diagram for explaining refractive index in the embodiment. [Figure 20] FIG. 13 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 21] FIG. 13 is a graph showing current density-voltage characteristics of a light-emitting element in the example. [Figure 22] FIG. 13 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Figure 23] FIG. 4 is a diagram illustrating an emission spectrum in the example. [Figure 24] FIG. 2 is a graph showing the external quantum efficiency vs. chromaticity x characteristics of a light-emitting element according to an embodiment. [Diagram 25] FIG. 4 is a diagram for explaining refractive index in the embodiment. [Figure 26] FIG. 13 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 27] FIG. 13 is a graph showing current density-voltage characteristics of a light-emitting element in the example. [Figure 28] FIG. 13 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Figure 29] FIG. 4 is a diagram illustrating an emission spectrum in the example. [Diagram 30] FIG. 11 is a diagram for explaining reliability test results according to the embodiment. [Diagram 31] FIG. 2 is a graph showing the external quantum efficiency vs. chromaticity x characteristics of a light-emitting element according to an embodiment. [Diagram 32] FIG. 2 is a graph for explaining the external quantum efficiency-y chromaticity characteristics of a light-emitting element according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Hereinafter, the embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the above description, and the embodiments and details thereof are not limited to those described above without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the embodiments described below. The terms of the present disclosure are not to be construed as being limited to the content.

[0031] In addition, the position, size, range, etc. of each component shown in the drawings are not necessarily shown in order to facilitate understanding. The actual position, size, range, etc. may not be shown. The present invention is not necessarily limited to the position, size, range, etc. disclosed in the drawings, etc.

[0032] In addition, in this specification, ordinal numbers such as 1st, 2nd, etc. are used for convenience. In some cases, the order of steps or layers may not be indicated. For example, "first" may be replaced with "second" or " " can be appropriately replaced with "the third" etc. The ordinal numbers used to identify an aspect of the present invention may not match those used in the present invention. be.

[0033] In addition, in this specification and the like, when explaining the configuration of the invention using drawings, The reference numerals may be commonly used among different drawings.

[0034] 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:

[0035] In addition, the refractive index n is divided into n Ordinary, which is the refractive index of ordinary rays, and n Ordinary, which is the refractive index of extraordinary rays. There are two types of n: n Extraordinary, which is the average of the two, and n average, which is the average of the two. In this specification, when the term "refractive index" is used, if anisotropy analysis is not performed, n If anisotropic analysis is performed, it may be read as n Ordinary. Also, anisotropy is the relationship between n Ordinary and n Extraordinary. It is expressed as the difference between n Ordinary and n Extraordinary. The sum of the nary values ​​divided by 3 is n average.

[0036] 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.

[0037] (Embodiment 1) In this embodiment, an electronic device according to one embodiment of the present invention will be described below with reference to FIG. do.

[0038] <Electronic device configuration example 1> The electronic device 50 has a pair of electrodes (electrodes 11 and 12) between a pair of substrates (substrate 10 and substrate 15). The organic semiconductor layer 20 has at least a carrier transporting layer. The organic semiconductor layer 20 has a conductive layer 30 and a functional layer 40. The organic semiconductor layer 20 may have a plurality of functional layers. stomach.

[0039] The functional layer 40 of the electronic device 50 preferably has a function of absorbing or emitting light. When light generated in the functional layer 40 is extracted from the side 1, the light that passes through the substrate 10 is guided to the electrode 11 and The electrons pass through the carrier transport layer 30 and the organic semiconductor layer 20 from the electrode 11 side. When light that enters the substrate 10 is absorbed by the functional layer 40, the light that passes through the substrate 10 is absorbed by the electrode 11 and the capacitor 12. The light generated in the functional layer 40 passes through the rear transport layer 30. In order for the functional layer 40 to efficiently absorb light, the electrode 11 and the carrier transport layer 30 It is preferable that the light attenuated in the

[0040] However, in the electronic device 50, a decay mode called an evanescent mode occurs. It is known that light is attenuated in the organic semiconductor layer 20 due to the above-mentioned reasons. In the case where light is generated, the light generated in the functional layer 40 is converted into an electron when passing through or being reflected by the electrode 11. Damping occurs due to spring mode.

[0041] It is known that if a layer with a low refractive index exists in the layer through which light passes, the amount of light that is attenuated decreases. In FIG. 1, a layer with a low refractive index is used for the carrier transport layer 30, so that the It is possible to suppress the attenuation of light.

[0042] However, in many cases, the carrier transport layer 30 has poor carrier transport or carrier injection properties. Therefore, the carrier transport layer 30 is a material having a carrier accepting property or a carrier donating property. The carrier-accepting or carrier-donating substance is often a material with a high refractive index. Therefore, the refractive index of the carrier transport layer 30 becomes high. In addition, it is difficult to obtain a layer with a low refractive index. When the donor substance is an organic compound, the organic compound has a structure such as a cyclohexane skeleton. It is known that the refractive index decreases when a saturated cyclic compound is included, but there is a problem with heat resistance. I did.

[0043] Here, the present inventors have mixed an organic compound with a low refractive index into the carrier transport layer 30. Therefore, even if a substance having a high refractive index and electron-accepting property is used, it is possible to obtain a material having a high refractive index while having a carrier transport property. Furthermore, it was found that a layer with a low refractive index could be fabricated using a tetraarylmethane skeleton or a tetraarylmethane skeleton. The carrier is an organic compound having either one of the arylsilane skeletons and an electron donating group. By mixing the material into the transport layer 30, even if a material having a high refractive index and electron-accepting property is used, It was found that a layer having a low refractive index while having carrier transport properties can be prepared. The compound also had excellent heat resistance.

[0044] The refractive index of the organic compound having a low refractive index is preferably 1 or more and 1.75 or less, and more preferably Preferably, the ratio is 1 or more and 1.73 or less, and more preferably 1.70 or less. In this way, a good electronic device with reduced light attenuation can be obtained.

[0045] Either one of the tetraarylmethane skeleton or the tetraarylsilane skeleton and an electron The refractive index of the organic compound having a child-donating group is preferably 1 or more and 1.75 or less, and more preferably Preferably, it is 1 or more and 1.73 or less, and more preferably, it is 1.70 or less. Thus, an electronic device with reduced light attenuation and good light extraction efficiency can be obtained.

[0046] <Electronic device configuration example 2> A light-emitting element, which is an example of an electronic device according to one embodiment of the present invention, will be described below with reference to FIG. The following is an explanation.

[0047] FIG. 2A is a schematic cross-sectional view of a light-emitting element 150 of one embodiment of the present invention.

[0048] The light emitting device 150 includes a substrate 200 and a substrate 210. The light-emitting device has a pair of electrodes (electrode 101 and electrode 102) and an EL element provided between the pair of electrodes. The EL layer 100 includes at least a light-emitting layer 130.

[0049] The EL layer 100 shown in FIG. 2A includes a hole injection layer 111, a hole injection layer 112, a light emitting layer 130, and a cathode. It has functional layers such as a hole transport layer 112 , an electron transport layer 118 , and an electron injection layer 119 .

[0050] In this embodiment, of the pair of electrodes, the electrode 101 is an anode, and the electrode 10 Although the description will be given assuming that 2 is a cathode, the configuration of the light emitting element 150 is not limited to this. Electrode 101 is a cathode, electrode 102 is an anode, and the layers between the electrodes are stacked in the reverse order. That is, from the anode side, a hole injection layer 111, a hole transport layer 112, and a light emitting layer The layer 130, the electron transport layer 118, and the electron injecting layer 119 may be stacked in this order.

[0051] In this embodiment, in FIG. 2(A), the electrode 101 (anode) side is the light extraction side. However, the configuration of the light emitting element 150 is not limited to this. Alternatively, the light may be collected from both the electrodes 101 and 102. It's okay to put it out.

[0052] The configuration of the EL layer 100 is not limited to the configuration shown in FIG. 2(A). 130, which includes a hole injection layer 111, a hole transport layer 112, an electron transport layer 118, and an electron injection layer 130. The layer 119 may or may not be present. or reducing the barrier for injection of electrons; improving the transportability of holes or electrons; Inhibits the transport of the fluorine-containing compound, suppresses the quenching phenomenon caused by the electrode, suppresses exciton diffusion, and The functional layers may each have a function of being able to It may be a single layer or a laminate of multiple layers.

[0053] FIG. 2(B) is a schematic cross-sectional view showing an example of the light-emitting layer 130 shown in FIG. The light-emitting layer 130 shown in FIG. 1B may include a guest material 131 and a host material 132. .

[0054] In order to efficiently emit light from the light emitting element 150, the light extraction efficiency of the light emitting element 150 must be high. However, as mentioned above, the organic EL element is in the evanescent mode. It is known that the attenuation mode reduces the light extraction efficiency. For example, in the light-emitting element 1 In the case of 50, when light generated in the light-emitting layer 130 passes through or is reflected by the electrode 101, It is attenuated by evanescent modes.

[0055] In order to reduce the attenuation of light due to the evanescent mode, the light emitting layer 130 and the electrode 101 One method is to increase the thickness of the layers between the positive hole injection layer 111 and the positive hole transport layer 112, for example. However, this configuration may cause problems such as an increase in driving voltage and a rise in manufacturing costs. .

[0056] Here, in the light emitting element 150, the light generated in the light emitting layer 130 is extracted to the outside. If a layer with a low refractive index exists before the light generated in the light-emitting layer 130 passes through the substrate 200, the light It is known that the extraction efficiency is improved.

[0057] Before the light generated in the light-emitting layer 130 is extracted to the outside, the hole injection layer 111 and the hole transport layer 112 are 112, the electrode 101 and the substrate 200. The refractive index of the transport layer 112 is preferably low. It is preferable that the refractive index is low.

[0058] However, in many cases, the hole injection layer 111 has an electron accepting property in order to obtain hole injection properties. The substance that has electron-donating properties is mixed with an organic compound that has electron-accepting properties. Since many materials have a high refractive index, the hole injection layer 111 has a high refractive index. It has been difficult to obtain a layer having a low refractive index while having hole injection properties. When the electron donating substance is an organic compound, the organic compound has a cyclohexane skeleton in its structure. It is known that the refractive index decreases when saturated cyclic compounds such as cyclic rings are included, but the heat resistance is improved. There was a problem.

[0059] Here, the present inventors have found that by using an organic compound with a low refractive index for the hole injection layer 111, Even if a substance having a high refractive index and electron-accepting property is used, it is possible to obtain a material having a low refractive index while having hole-injecting properties. Furthermore, the present inventors have found that a thin layer can be fabricated by using a tetraarylmethane skeleton. or tetraarylsilane skeleton and an electron donating group. By mixing an organic compound having a high refractive index and electron-accepting property into the hole injection layer 111, It has been found that a layer having a low refractive index and carrier transport properties can be fabricated even if a material having such a refractive index is used. Furthermore, it was found that the organic compound has excellent heat resistance. The transition temperature (Tg) is preferably 100° C. or higher.

[0060] The refractive index of the organic compound having a low refractive index is preferably 1 or more and 1.75 or less, and more preferably Preferably, the ratio is 1 or more and 1.73 or less, and more preferably 1.70 or less. As a result, a light emitting device with good light extraction efficiency can be obtained.

[0061] Either one of the tetraarylmethane skeleton or the tetraarylsilane skeleton and an electron The organic compound having a child-donating group preferably has a refractive index of 1 or more and 1.75 or less, and more preferably Preferably, it is 1 or more and 1.73 or less, and more preferably, it is 1.70 or less. Thus, a light emitting element with good light extraction efficiency can be obtained.

[0062] As described above, the presence of a layer with a low refractive index between the light emitting layer 130 and the substrate 200 improves the light extraction efficiency. However, by introducing a layer with a low refractive index in addition to the hole injection layer 111 and the hole transport layer 112, However, this increases the number of layers to be fabricated, making the fabrication process of the light-emitting device more complicated. In one embodiment of the present invention, a layer having a low refractive index and hole injection properties is produced. Therefore, it is possible to use the conventional manufacturing process, i.e., while maintaining the number of layers to be manufactured. This can improve the light extraction efficiency of the light emitting device.

[0063] Similarly, in one aspect of the present invention, a tetraarylmethane skeleton or a tetraarylsilyl group is By using an organic compound having either one of the orchid skeletons and an electron donating group, It is possible to fabricate layers with low refractive index and hole injection properties, which is advantageous over conventional fabrication processes. The light extraction efficiency of the light emitting device can be improved by using a process, i.e., without increasing the number of layers to be fabricated. The rate can be improved.

[0064] Another embodiment of the present invention relates to an EL layer between an anode and a cathode. This technique can be combined with other light extraction enhancing techniques such as OLED.

[0065] In addition, one embodiment of the present invention uses an organic compound having an electron donating property as an organic compound having a low refractive index. By adopting such a configuration, the refractive index of the hole injection layer 111 is reduced. Since the hole injection characteristics can be improved while maintaining the light extraction efficiency, It is possible to provide a light-emitting element having a low voltage. It is more preferable that the compound has a tetraarylsilane skeleton.

[0066] In addition, the refractive index of the hole injection layer 111 is preferably lower than the refractive index of the light emitting layer 130. This can reduce attenuation of light emitted from the light emitting layer 130 due to evanescent waves. In addition, the refractive index of the hole injection layer 111 is lower than that of the hole transport layer 112. It is more preferable that the refractive index of the hole transport layer 112 is lower than that of the light emitting layer 130. This reduces the refractive index difference between the light emitting layer 130 and the hole injection layer 111. Furthermore, the light extraction efficiency can be improved.

[0067] In order to suppress the waveguide mode of the EL layer, the layer through which the light generated in the light-emitting layer 130 passes is Therefore, the light emitting layer 130 being in contact with the electrode 101 is preferable. This is a preferable configuration when considering the output efficiency, but this configuration has the effect of carrier balance. In some cases, the light emission efficiency of the light emitting layer 130 may decrease due to the influence of the plasmon effect. The hole injection layer 111 and the hole transport layer 112 are layers necessary for the EL layer to function efficiently. Therefore, it is preferable that the hole injection layer 111 and the hole transport layer 112 are in contact with each other. More preferably, the transmittance layer 112 and the light-emitting layer 130 are in contact with each other.

[0068] In addition, it is preferable that the refractive index of the hole injection layer 111 is lower than that of the electrode 101. By this, the relationship between the refractive index n HIL of the hole injection layer 111 and the refractive index n cat. of the electrode 101 is Since the relationship is n cat. / n HIL>1, light is guided from the hole injection layer 111 to the electrode 101. It is possible to suppress total reflection when passing through. In other words, it is possible to suppress the guided mode. In addition, the attenuation of light due to evanescent modes caused by reflection can be suppressed. Cut.

[0069] The refractive index of the hole injection layer 111 is preferably 1 or more and 1.80 or less. is 1 or more and 1.78 or less, more preferably 1 or more and 1.75 or less. Thus, good light extraction efficiency can be obtained.

[0070] In addition, the hole injection layer 111 is made of an organic compound having an electron donating property and an organic compound having an electron accepting property. It is preferable to mix the materials. By using this structure, it is possible to obtain good hole injection characteristics. can.

[0071] Here, the mixing ratio of the organic compound and the substance having electron accepting property is The volume ratio of the substance to the organic compound is preferably 0.01 to 0.3. By using this structure, even if a substance with a high refractive index is used as the substance having electron accepting properties, the organic compound By using an organic compound having a low refractive index as the material, a hole injection layer 111 having a low refractive index can be formed. The present inventors have found that it is possible to prepare

[0072] The above-mentioned attenuation of light by evanescent waves can also occur in light incident on electronic devices. For example, when the electronic device according to one embodiment of the present invention is applied to a solar cell, evanescence This suppresses the attenuation of light due to the incident light, improving the light trapping effect of the solar cell. Therefore, the electronic device according to one aspect of the present invention can be suitably used in a solar cell. In this case, the functional layer 40 in the electronic device 50 shown in FIG. The term may be read as a layer, a light absorbing layer, or a photovoltaic layer.

[0073] <Organic Compound Used in Hole Injection Layer 111> Here, organic compounds that can be suitably used for the hole injection layer 111 will be described.

[0074] It is preferable to use an organic compound having a small refractive index for the hole injection layer 111. The refractive index of an electron is expressed by the Lorentz-Lorenz equation (Equation (1)) shown below.

[0075]

number

[0076] By transforming equation (1), we obtain equation (2).

[0077]

number

[0078] In formula (1) and formula (2), n is the refractive index, α is the polarizability, N is the number of molecules in a unit volume, and ρ is the density. degrees, N A is the Avogadro's number, M is the molecular weight, V0 is the molar volume, and [R] is the atomic refraction.

[0079] From equation (2), in order to reduce the refractive index n, it is necessary to reduce φ. From equation (1), In order to reduce φ, the atomic refraction [R] should be reduced. In other words, the refractive index n should be reduced. To reduce this, it is necessary to select an organic compound that has a small atomic refraction [R].

[0080] The above formula is for polymers, so when applied to low molecular weight compounds, the calculated value may differ. Although some deviations are expected, the general trend is considered to be similar. The organic compound used in the injection layer 111 is selected so as to have a small atomic refraction [R]. It is preferable that the hole injection layer 111 has a hole injection property. Therefore, the organic compound used in the hole injection layer 111 should further contain a compound having a molecular weight of 100 or more, such as an aromatic compound. It is more preferable that the organic compound has π-conjugation and electron donating property. By this, it is possible to prepare a hole injection layer 111 having a low refractive index and excellent hole injection properties. do.

[0081] The atomic refraction [R] is a substituent that contains fluorine, such as a fluoro group or a trifluoromethyl group, or a cycloalkyl group. Hexyl group and aromatic ring-mediated bonds have sp 3 The conjugation between aromatic rings, represented by hybrid orbitals, is broken. In addition, the molecular weight of organic compounds with non-alternant hydrocarbons tends to be small. Since the conjugated system does not extend throughout the molecule, the atomic refraction [R] tends to be small. Therefore, the organic compound used in the hole injection layer 111 is an organic compound having the above-mentioned substituents or bonds. is preferred.

[0082] The organic compound used in the hole injection layer 111 may have an aromatic amine skeleton, a pyrrole skeleton, a thiophene skeleton, or the like. Organic compounds with a cyclic skeleton and bulky groups such as methyl, t-butyl, and isopropyl groups An organic compound having an aromatic ring with a substituent can also be suitably used. They tend to have a π-conjugated system in the molecule and also have a low refractive index.

[0083] An example of a structure in which the conjugation between aromatic rings is broken in the bond via the aromatic ring is the following general structure: A tetraarylmethane skeleton represented by formula (100), a tetraarylmethane skeleton represented by general formula (101) Examples of the skeleton include an arylsilane skeleton and a cyclohexyl skeleton. The tetraarylsilane skeleton has a low refractive index and is more heat resistant than the cyclohexyl skeleton. Therefore, it can be suitably used for the hole injection layer 111. Since thin films can be easily formed, it can be used favorably in electronic devices such as organic electroluminescence (EL). can.

[0084] [ka]

[0085] In addition, the organic compound used in the hole injection layer 111 preferably has electron donating properties. Examples of the skeleton having such a property include aromatic amino groups represented by the following general formulas (200) to (220). Examples of the general formulas (210) to (213) include a cyclic heteroaromatic skeleton and a π-electron-rich heteroaromatic skeleton. X represents oxygen or sulfur.

[0086] [ka]

[0087] The aromatic amine skeleton (specifically, for example, a triarylamine skeleton), π-electron excess Heteroaromatic ring skeleton (specifically, for example, furan skeleton, thiophene skeleton, pyrrole skeleton, azelate skeleton, etc.) The ring having a pyridine skeleton or an acridine skeleton may have a substituent. Examples of the alkyl group include an alkyl group having 1 to 6 carbon atoms and a cycloalkyl group having 3 to 6 carbon atoms. Alternatively, a substituted or unsubstituted aryl group having 6 to 12 carbon atoms may be selected. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethylene group, and an ethylene group. ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-hexyl group, etc. Also, cycloalkyl groups having 3 to 6 carbon atoms can be mentioned. Specific examples of the aryl group include a cyclopropyl group, a cyclobutyl group, and a cyclopentyl group. In addition, aryl groups having 6 to 12 carbon atoms, such as aryl groups and cyclohexyl groups, can be given. Specific examples of the alkyl group include a phenyl group, a naphthyl group, and a biphenyl group. The above-mentioned substituents may be bonded to each other to form a ring. For example, the carbon atom at the 9th position of the fluorene skeleton may have two phenyl groups as substituents. When the phenyl groups are bonded to each other, a spirofluorene skeleton is formed. In the case of unsubstituted aryl groups, the ease of synthesis and the cost of raw materials are not so high. It is advantageous.

[0088] The electron-donating skeleton is, as described above, an aromatic amine skeleton, a pyrrole skeleton, an azepi skeleton, The skeleton is preferably an odd-numbered ring skeleton such as an aryl skeleton or an acridine skeleton. The atomic refraction [R] is also low, so by having these skeletons in the molecule, It is possible to obtain an organic compound having excellent donating properties and a low refractive index.

[0089] Also, Ar 1 ~Ar 8 each independently represents an aryl group having 6 to 13 carbon atoms or is an aromatic amine skeleton or a π-electron permeable compound represented by the above general formulas (200) to (220). The aryl group may have a substituent, and the substituents may be mutually selected from the group consisting of aryl, aryl, aryl, aryl and heteroaromatic skeletons. They may be bonded to form a ring. Examples of such a ring include a ring at the 9-position of a fluorenyl group. The carbon has two phenyl groups as substituents, and the phenyl groups are bonded to each other to form In the case where a spirofluorene skeleton is formed, for example, Specific examples of the aryl group include a phenyl group, a naphthalenyl group, and a fluorenyl group. In addition, when the aryl group has a substituent, the substituent and Examples of the alkyl group include an alkyl group having 1 to 6 carbon atoms and a cycloalkyl group having 3 to 6 carbon atoms. Alternatively, an aryl group having 6 to 12 carbon atoms may be selected. Specific examples of alkyl groups having a prime number of 6 include methyl, ethyl, propyl, and isopropyl groups. Examples include isopropyl, butyl, isobutyl, tert-butyl, and n-hexyl groups. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include: For example, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, etc. Examples of the aryl group having 6 to 12 carbon atoms include Specific examples include a phenyl group and a naphthyl group.

[0090] Also, Ar 1 ~Ar 8 The aryl group represented by the following structural formula can be used as an example of the aryl group represented by the following structural formula: However, the groups that can be used as the aryl group are not limited to these. do not have.

[0091] [ka]

[0092] Also, Ar 1 ~Ar8 When is an aryl group, the aryl group may be substituted or unsubstituted. Substituents with a relatively small extent of π-conjugated system, such as aryl groups having 6 to 13 carbon atoms It is preferable that the π-conjugated system is a substituted or unsubstituted phenyl group, and it is more preferable that the π-conjugated system is a substituted or unsubstituted phenyl group. Small substituents tend to have small atomic refractions [R]. On the other hand, aryl groups such as alkenes have small π-conjugated systems. Organic compounds are not suitable for electronic devices because of their poor carrier transport properties. An aryl group having 6 to 13 carbon atoms, particularly a phenyl group, having a carrier transporting property. In particular, organic compounds with small π-conjugated systems are preferable as organic compounds for use in the hole injection layer 111 . Moreover, an odd-numbered ring substituent is preferred because it has a small atomic refraction [R].

[0093] In addition, in the general formulas (200) to (220), R 1 ~R 11 are each independently hydrogen an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, and a propyl group. butyl, isobutyl, tert-butyl, n-hexyl Examples of the cycloalkyl group having 3 to 6 carbon atoms include Specifically, for example, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, Examples of the aryl group having 6 to 13 carbon atoms include an aryl group having 6 to 13 carbon atoms, and the like. Specific examples of the alkyl group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorenyl group. Furthermore, the above-mentioned aryl group and phenyl group may have a substituent. The substituents may be bonded to each other to form a ring. an alkyl group having 3 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a cycloalkyl group having 6 carbon atoms An aryl group having from 1 to 6 carbon atoms can also be selected. Specific examples of the group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a bromo group, and the like. Examples of the alkyl group include butyl, isobutyl, tert-butyl, and n-hexyl groups. Specific examples of the cycloalkyl group having 3 to 6 carbon atoms include cycloalkyl groups such as: Examples of the aryl group include propyl, cyclobutyl, cyclopentyl, and cyclohexyl groups. Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a naphthalene group, and the like. Specific examples include a butyl group and a biphenyl group.

[0094] Also, R 1 ~R 11 The hydrogen, alkyl group or aryl group represented by the following formula (I) is, for example, Groups represented by structural formulas (R-1) to (R-27) can be used. The groups that can be used as the alkyl or aryl group are not limited to these.

[0095] [ka]

[0096] In addition, in the general formulas (200) to (220), Ar 9 ~Ar 13 is a carbon number of 6 to 10 carbons represents an arylene group of the formula 13, which may have a substituent, and which is They may be bonded to each other to form a ring. Examples of such rings include the fluorenyl group. The carbon atom at position 9 has two phenyl groups as substituents, and these phenyl groups are bonded together to form Therefore, a spirofluorene skeleton may be formed. Examples of the arylene group of 13 include a phenylene group, a naphthalenediyl group, and a biphenylene group. Specific examples of the arylene group include an arylene group and a fluorenediyl group. When the group has a substituent, the substituent is an alkyl group having 1 to 6 carbon atoms, Cycloalkyl groups having 3 to 6 carbon atoms or aryl groups having 6 to 12 carbon atoms are also usable. Specific examples of the alkyl group having 1 to 6 carbon atoms include , methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert Examples of the alkyl group include t-butyl and n-hexyl groups. Specific examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, cyclopentyl, cyclohexyl, and the like. Examples of aryl groups having a prime number of 12 include phenyl groups, naphthyl groups, and biphenyl groups. The following can be given as a specific example.

[0097] Also, Ar 9 ~Ar 13 The arylene group represented by the following structural formula (Ar-1 Groups represented by Ar 2) to (Ar-25) can be used. 9 ~Ar 1 3 The groups that can be used as are not limited to these.

[0098] [ka]

[0099] As described above, the organic compound used in the hole injection layer 111 has a tetraarylmethane skeleton or It is preferable that the organic compound has a tetraarylsilane skeleton and electron donating properties. An example of the compound is 9-(4-t-butylphenyl)-3,4-ditrityl-9H- Carbazole (abbreviation: CzC), 9-(4-t-butylphenyl)-3,4-diphenyl Nylsilyl-9H-carbazole (abbreviation: CzSi), 4,4,8,8,-12,12- Hexa-p-tolyl-4H-8H-12H-12C-aza-dibenzo[cd,mn]pi FATPA, 4,4'-bis(dibenzo-azepin-1-yl)-biphenyl Nyl (abbreviation: BazBP), 4,4'-bis(dihydro-dibenzo-azepin-1-yl )-biphenyl (abbreviation: HBazBP), 4,4'-(diphenylmethylene)bis(N, N-Diphenylamine) (abbreviation: TCBPA), 4,4'-(diphenylsilanediyl) Bis(N,N-diphenylamine) (abbreviation: TSBPA) and others. These structures The formula is shown below. The tetraarylmethane skeleton or the tetraarylsilane skeleton and The organic compounds having electron donating properties are not limited to the above. The structural formulas of these compounds are shown below.

[0100] [ka]

[0101] Note that a low-molecular-weight organic compound can be suitably used for the electronic device according to one embodiment of the present invention. By using a low molecular weight organic compound, all layers included in the EL layer 100 can be vacuum-insulated. Since the film can be formed by vapor deposition, the manufacturing process can be simplified.

[0102] <Improvement of light extraction efficiency by adjusting the optical path length> In addition, in the electronic device according to one embodiment of the present invention, the optical path length is controlled, thereby The light extraction efficiency can be improved. It can extract long-range light efficiently.

[0103] For example, in order to efficiently extract light of a desired wavelength (wavelength: λ) from the light emitting layer 130, In addition, light of a desired wavelength of the light emitting layer 130 is obtained from the interface between the electrode 101 and the hole injection layer 111. The optical distance to the light emitting region 134 is (2m'-1)λ / 4 (where m' is a natural number). It is preferable to adjust the light-emitting region so that the light-emitting region is in the vicinity of the light-emitting layer 13. 0 represents the recombination region of holes and electrons.

[0104] By performing such optical adjustments, the attenuation of light due to evanescent modes is reduced. Therefore, the efficiency of extracting light from the light emitting layer 130 can be improved.

[0105] In addition, the interface between the substrate 200 and the electrode 101 and the region of the light emitting layer 130 from which light of a desired wavelength can be obtained ( The optical distance to the light emitting region 134) is adjusted to be close to mλ / 2 (where m is a natural number). By performing such optical adjustment, it is possible to obtain a high-quality image by using the evanescent mode. Since the attenuation of light due to the light emitting layer 130 can be reduced, the light extraction efficiency from the light emitting layer 130 can be improved. It is possible.

[0106] In order to perform the above optical adjustment, the thickness of the hole injection layer 111 or the hole transport layer 112 is adjusted. However, when the refractive index of the hole injection layer 111 is high, the optical path length tends to be long. Therefore, it may be difficult to adjust the optical path length, or the thickness of the hole injection layer 111 may increase, resulting in an increase in the driving voltage. However, in one embodiment of the present invention, the hole injection layer 111 has a low refractive index. Therefore, it is easy to control the optical path length and the film thickness can be made thin. Not only has the light extraction efficiency from 130 been improved, but the fabrication process of the light-emitting device has also been simplified and A light emitting element having a driving voltage can be realized.

[0107] The above-mentioned attenuation of light by evanescent waves can also occur in light incident on electronic devices. For example, when the electronic device according to one embodiment of the present invention is applied to a solar cell, evanescence This suppresses the attenuation of light due to the incident light, and therefore enhances the light trapping effect of the organic solar cell. Therefore, the electronic device according to one aspect of the present invention is suitable for a solar cell. In this case, the functional layer 40 in the electronic device 50 shown in FIG. It can be interpreted as active layer.

[0108] In addition, in the above-mentioned structure, the optical path length of the light emitting element is adjusted to the desired wavelength λ, thereby efficiently controlling the light. We have explained the structure for extracting the light efficiently, and will explain an example of applying this to a solar cell using Figure 1. The pair of electrodes is arranged so that the optical path length is different from the wavelength λ′ of the light incident on the electronic device 50. It is preferable to adjust the thickness of the organic semiconductor layer 20 between the electrodes in FIG. With this configuration, the light incident on the electronic device 50 is efficiently guided through the electronic device 50. Furthermore, in the electronic device according to one embodiment of the present invention, This suppresses the attenuation of light caused by the incident light, resulting in a more efficient light trapping effect. can be obtained.

[0109] <Material> Next, components of a light-emitting element, which is an example of an electronic device according to one embodiment of the present invention, will be described in detail. The following provides an explanation of this.

[0110] <Light-emitting layer> The light-emitting layer 130 includes at least a host material 131 and a guest material 132. As described later, the host material 131 is preferably an organic compound 131_1 and an organic In the light-emitting layer 130, the host material 131 may have a weight ratio of The guest material 132 is present in the host material 131 in the most amount. When 132 is a fluorescent compound, the host material 131 (organic compound 131_1) of the light-emitting layer 130 and the organic compound 131_2) is a guest material of the light-emitting layer 130 (guest material 13 2) is preferably higher than the S1 level. In addition, when the guest material 132 is a phosphorescent compound, In this case, the host material 131 of the light-emitting layer 130 (organic compound 131_1 and organic compound 131_2) The T1 level of the guest material 132 in the light-emitting layer 130 is higher than the T1 level of the guest material 132 in the light-emitting layer 130. It is preferred.

[0111] The organic compound 131_1 is a heteroaromatic skeleton having 1 to 20 carbon atoms and containing two or more nitrogen atoms. In particular, compounds having a pyrimidine skeleton and a triazine skeleton are preferred. As the organic compound 131_1, a material having a higher electron transporting property than a hole transporting property (electron A 1×10 -6 cm 2 / Vs or higher electron mobility It is preferable that the material be one having such a property.

[0112] Specifically, for example, 4,6-bis[3-(phenanthren-9-yl)phenyl]pyridine 4,6mPnP2Pm, 4,6-bis[3-(4-dibenzothienyl) phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-( 9H-Carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm) Heterocyclic compounds with diazine skeletons such as 2-{4-[3-(N-phenyl-9H- Carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl Phenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2-{3-[3-(phenyl Zo[b]naphtho[1,2-d]furan-8-yl)phenyl]phenyl}-4,6-difluoro phenyl-1,3,5-triazine (abbreviation: mBnfBPTzn), 2,4,6-tris( Biphenyl-3-yl)-1,3,5-triazine (abbreviation: T2T), 2,4,6-tri S[3'-(pyridin-3-yl)-biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPyTz), 9-[4-(3,5-diphenyl-1H-1,2,4- riazol-1-yl)]phenyl-9H-carbazole (abbreviation: CzTAZ(1H)) Heterocyclic compounds having a triazine skeleton, a pyrimidine skeleton, or a triazole skeleton such as In addition, the heterocyclic compound having the above skeleton has an electron transporting property. The materials mentioned here have a high valence of 1×10 -6 cm 2 / V It is a material that has an electron mobility of 1.5 or more. Note that it is a material that has a higher electron transporting property than a hole transporting property. If desired, materials other than those mentioned above may be used.

[0113] In addition, organic compounds 131_1 include pyridine derivatives, pyrazine derivatives, and pyridazine derivatives. Conductors, bipyridine derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, phenane Compounds such as thoroline derivatives and purine derivatives can also be used. The object is 1×10 -6 cm 2 It is preferable that the material has an electron mobility of .beta. / Vs or more.

[0114] Specifically, for example, bathophenanthroline (abbreviation: BPhen), bathocuproine ( Heterocyclic compounds with pyridine skeletons such as 2-[3-(dibenzothiophene) 2mDBTPD Bq-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]quinoxa Phosphorus (abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H-carbazo (2CzPDBq- III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h] Quinoxaline (abbreviation: 7mDBTPDBq-II) and 6-[3-(dibenzothiophene 6m-4-phenyl)dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDB q-II), 2-[3-(3,9'-bi-9H-carbazol-9-yl)phenyl]di Benzo[f,h]quinoxaline (abbreviation: 2mCzCzPDBq) and other pyrazine skeletons Heteroaromatic ring compounds and 3,5-bis[3-(9H-carbazol-9-yl)phenyl 1,3,5-tri[3-(3-pyridyl)phenyl]pyridine (abbreviation: 35DCzPPy), Heterocyclic compounds with a pyridine skeleton, such as [phenyl]benzene (abbreviation: TmPyPB), are also used. In addition, poly(2,5-pyridinediyl) (abbreviation: PPy), poly[( 9,9-Dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl) )] (abbreviation: PF-Py), poly[(9,9-dioctylfluorene-2,7-diyl) -co-(2,2'-bipyridine-6,6'-diyl)] (abbreviation: PF-BPy) It is also possible to use a polymer compound having a higher electron transporting property than a hole transporting property. If desired, materials other than those mentioned above may be used.

[0115] The organic compound 131_2 is a heteroaromatic skeleton having 1 to 20 carbon atoms and containing two or more nitrogen atoms. It is preferable that the structure is a nitrogen-containing five-membered heterocyclic skeleton. For example, an imidazole skeleton is Examples of organic compounds include those with a triazole skeleton and a tetrazole skeleton. As the material 2, a material having a higher hole transporting property than that of an electron (hole transporting material) can be used. , 1×10 -6 cm 2 It is preferable that the material has a hole mobility of .DELTA..times ... The hole transporting material may be a polymer compound.

[0116] Specifically, for example, 3-(4-biphenylyl)-4-phenyl-5-(4-tert- butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 9-[4-(4,5- Diphenyl-4H-1,2,4-triazol-3-yl)phenyl]-9H-carbazo CzTAZ1, 2,2',2''-(1,3,5-benzenetriyl) Tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(diphenyl Benzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole ( Abbreviated name: mDBTBIm-II) etc. can be used.

[0117] As the organic compound 131_2, other nitrogen-containing heterocyclic five-membered ring skeleton or tertiary amine skeleton Compounds having a pyrrole skeleton or an aromatic alkyl group can also be preferably used. Examples include indole derivatives, carbazole derivatives, triarylamine skeletons. The organic compound 131_2 is a compound that has a hole rather than an electron. A material with high transport properties (hole transport material) of 1×10 -6 cm 2 / Vs It is preferable that the hole transport material is a polymer having a hole mobility of at least 100 nm. It may be a compound.

[0118] As the material having high hole transport properties, specifically, aromatic amine compounds include N, N'-Di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DT DPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenyla N,N'-bis{4-[bis(3-methylphenyl) {N,N'-diphenyl-(1,1'-biphenyl)-4,4' -diamine (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylamino [phenyl]-N-phenylamino]benzene (abbreviation: DPA3B), etc. .

[0119] 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) , 4,4'-bis(9-carbazolyl)-2,2'-dimethyl-biphenyl (abbreviation: dm CBP) and the like.

[0120] Another example of a carbazole derivative is 4,4'-di(N-carbazolyl)biphene. Nyl (abbreviation: CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzoyl Zene (abbreviation: TCPB), 9-[4-(10-phenyl-9-anthryl)phenyl]- 9H-Carbazolyl (abbreviation: CzPA), 1,4-bis[4-(N-carbazolyl)phenyl] nyl)-2,3,5,6-tetraphenylbenzene and the like can be used.

[0121] Also, N,N-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl ]-9H-Carbazole-3-amine (abbreviation: CzA1PA), 4-(10-phenyl- 9-Anthryl)triphenylamine (abbreviation: DPhPA), 4-(9H-carbazole -9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl] PCAPA, N,9-diphenyl -N-{4-[4-(10-phenyl-9-anthryl)phenyl]phenyl}-9H- Carbazole-3-amine (abbreviation: PCAPBA), N,9-diphenyl-N-(9,1 0-Diphenyl-2-anthryl)-9H-carbazole-3-amine (abbreviation: 2PCA PA), 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9 H-Carbazole (abbreviation: PCzPA), 3,6-diphenyl-9-[4-(10-phenyl N, N,N',N',N'',N'',N''',N'''-Octaphenyldibenzo[g, p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), 1,1-bis- (4-bis(4-methylphenyl)-amino-phenyl)-cyclohexane (abbreviation: T APC) can be used.

[0122] In addition, poly(N-vinylcarbazole) (abbreviation: PVK) and poly(4-vinyltriphenylphosphine) nylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenyl Amino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide]( abbreviation: PTPDMA), poly[N,N'-bis(4-butylphenyl)-N,N'-bis Polymer compounds such as Poly(phenyl)benzidine (abbreviation: Poly-TPD) can also be used. can.

[0123] Furthermore, examples of materials with high hole transport properties include 4,4'-bis[N-(1-naphthalene) N,N'-phenylamino]biphenyl (abbreviation: NPB or α-NPD) Bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4, 4'-diamine (abbreviation: TPD), 4,4',4''-tris(carbazol-9-yl) ) triphenylamine (abbreviation: TCTA), 4,4',4''-tris[N-(1-naphthalene 1'-TNATA, 4,4 ',4''-Tris(N,N-diphenylamino)triphenylamine (abbreviation: TDAT A) 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino] Triphenylamine (abbreviation: MTDATA), 4,4'-bis[N-(spiro-9,9' -bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4 -Phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylphosphine 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 DFLADFL, 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 (abbreviation: 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-carbazone 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] 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 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 PCPPn, 3,3'-bis(9- phenyl-9H-carbazole) (abbreviation: PCCP), 1,3-bis(N-carbazolyl )benzene (abbreviation: mCP), 3,6-bis(3,5-diphenylphenyl)-9-phenyl Nylcarbazole (abbreviation: CzTP), 3,6-di(9H-carbazol-9-yl)- 9-Phenyl-9H-carbazole (abbreviation: PhCzGI), 2,8-di(9H-carbazole) amine compounds such as carbazole-9-yl-dibenzothiophene (abbreviation: Cz2DBT), Among the above-mentioned compounds, a pyrrole skeleton, an aromatic Compounds having an aromatic amine skeleton are preferred because they are stable and have good reliability. The compound having the formula (I) has high hole transporting properties and contributes to reducing the driving voltage.

[0124] In the light-emitting layer 130, the guest material 132 is not particularly limited, but may be a fluorescent material. The compounds include anthracene derivatives, tetracene derivatives, chrysene derivatives, phenanthrene derivatives, pyrene derivatives, perylene derivatives, stilbene derivatives, acridone derivatives, chlo Marine derivatives, phenoxazine derivatives, phenothiazine derivatives, etc. are preferred. For example, The following materials can be used:

[0125] Specifically, 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2 ,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl -9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2 BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoro 1,6-Pyrene-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn) , N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H -fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMem FLPAPrn), N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl )phenyl]-N,N'-bis(4-tert-butylphenyl)pyrene-1,6-diazo 1,6tBu-FLPAPrn, N,N'-diphenyl-N,N'-bis(1,6tBu-FLPAPrn) [4-(9-phenyl-9H-fluoren-9-yl)phenyl]-3,8-dicyclohexyl Xylpyrene-1,6-diamine (abbreviation: ch-1,6FLPAPrn), N,N'-biphenyl S[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbe YGA2S, 4-(9H-carbazol-9-yl) -4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA) , 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-anthracene N,9-diphenyl-N-[4- (10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation Name: PCAPA), Perylene, 2,5,8,11-tetra(tert-butyl)perylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl- 9H-Carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), N,N' '-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene) Bis[N,N',N'-triphenyl-1,4-phenylenediamine] (abbreviation: DPAB PA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl] phenyl]-9H-carbazol-3-amine (abbreviation: 2PCAPPA), N-[4-(9 ,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1 ,4-Phenylenediamine (abbreviation: 2DPAPPA), N,N,N',N',N'',N '',N''',N'''-Octaphenyldibenzo[g,p]chrysene-2,7,10 ,15-Tetraamine (abbreviation: DBC1), Coumarin 30, N-(9,10-diphenyl -2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2 PCAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthracene aryl]-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPh A), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl -1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(1,1 '-biphenyl-2-yl)-2-anthryl]-N,N',N'-triphenyl-1, 4-Phenylenediamine (abbreviation: 2DPABPhA), 9,10-bis(1,1'-biphenyl) phenyl-2-yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N- Phenylanthracene-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenyl Dianthracene-9-amine (abbreviation: DPhAPhA), Coumarin 6, Coumarin 545T , N,N'-diphenylquinacridone (abbreviation: DPQd), rubrene, 2,8-di-te rt-Butyl-5,11-bis(4-tert-butylphenyl)-6,12-diphenyl Tetrathracene (abbreviation: TBRb), Nile Red, 5,12-bis(1,1'-biphenyl) 2-(2-(2-phenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), [4-(Dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-yl 2-(2-methyl-6-[2-(2,3-dimethylphenyl)propanedinitrile (abbreviation: DCM1), ,6,7-Tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl ]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N ',N'-Tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methyl phenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: p -mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl 2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl )Ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI) , 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3, 6,7-Tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl] -4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2, 6-Bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-yl 2-{2,6-bis[2-(8- Methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H -benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}p Dopanedinitrile (abbreviation: BisDCJTM), 5,10,15,20-tetraphenyl Bisbenzo[5,6]indeno[1,2,3-cd:1',2',3'-lm]perylene , etc.

[0126] The guest material 132 (phosphorescent compound) is an iridium, rhodium, or platinum-based Organometallic complexes or metal complexes are included, among which organic iridium complexes, e.g. iridium The orthometalated ligand is preferably a 4H-triazolium complex. 1H-triazole ligands, 1H-triazole ligands, imidazole ligands, pyridine ligands, pyrimidine ligands Examples of the ligands include quinolinone, pyrazine, and isoquinoline. Examples of the platinum complex include a platinum complex having a porphyrin ligand.

[0127] 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-tris( riazolate)iridium(III) (abbreviation: Ir(Mptz)3), tris[4-(3- Biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]i Iridium(III) (abbreviation: Ir(iPrptz-3b)3), tris[3-(5-biphenyl] (phenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]irid Ir(III) (abbreviation: Ir(iPr5btz)3), a 4H-triazole skeleton and organometallic iridium complexes having tris[3-methyl-1-(2-methylphenyl) -5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: Ir (Mptz1-mp)3), tris(1-methyl-5-phenyl-3-propyl-1H- 1,2,4-Triazolate)iridium(III) (abbreviation: Ir(Prptz1-Me) 3) and fac-triazole-based organometallic iridium complexes. S[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole] Iridium(III) (abbreviation: Ir(iPrpmi)3), tris[3-(2,6-dimethyl phenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(I II) (abbreviation: Ir(dmpimpt-Me)3), tris{2-[1-(4-cyano- 2,6-Diisobutylphenyl)-1H-benzimidazol-2-yl-κN3 ]Fe iridium(III) (abbreviation: Ir(pbi-diBuCNp)3) We have developed organometallic iridium complexes with imidazole skeletons and bis[2-(4',6'-difluorophenyl)phenyl] (fluorophenyl)pyridinato-N,C 2’ ]Iridium(III) tetrakis(1-pyra 2-(4',6'-difluorophenyl) bis[2-(4',6'-difluorophenyl) Pyridinate-N,C 2’ ]Iridium(III) picolinate (abbreviation: FIrpic), Bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C 2 ’}Iridium(III) picolinate (abbreviation: Ir(CF3ppy)2(pic)), Bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ]iridium( III) Having an electron-withdrawing group such as acetylacetonate (abbreviation: FIr(acac)) An example of the organometallic iridium complex is a phenylpyridine derivative having the above-mentioned structure as a ligand. Among them, 4H-triazole skeleton, 1H-triazole skeleton and imidazole skeleton are Organometallic iridium complexes with nitrogen-containing five-membered heterocyclic skeletons have high triplet excitation energies. It is particularly preferred because it has a high luminous efficiency and is excellent in reliability and luminous efficiency.

[0128] In addition, examples of substances having a green or yellow emission peak include tris(4-methylphenyl) Ir(mppm)3, Tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: I r(tBuppm)3), (acetylacetonato)bis(6-methyl-4-phenylpyridine Iridium(III) (abbreviation: Ir(mppm)2(acac)), (acetylacetonate ruacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium( III) (abbreviation: Ir(tBuppm)2(acac)), (acetylacetonato)bis [4-(2-norbornyl)-6-phenylpyrimidinato]iridium(III) (abbreviation Ir(nbppm)2(acac)), (acetylacetonato)bis[5-methyl-6 -(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: Ir(mpmppm)2(acac)), (acetylacetonato)bis{4,6-dimethyl 2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN 3 ]Phenyl- {κC}iridium(III) (abbreviation: Ir(dmppm-dmp)2(acac)), ( Acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III)( Abbreviation: Ir(dppm)2(acac) (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazine) Iridium(III) (abbreviation: Ir(mppr-Me)2(acac)), (acetylacetonate arylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinate)irid Pyrazine skeleton such as Ir(III) (abbreviation: Ir(mppr-iPr)2(acac)) Organometallic iridium complexes and tris(2-phenylpyridinato-N,C 2’ ) Iridium(III) (abbreviation: Ir(ppy)3), bis(2-phenylpyridinato-N ,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(ppy)2(ac ac)), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: Ir(bzq)2(acac)), tris(benzo[h]quinolinato)iridium Ir(III) (abbreviation: Ir(bzq)3), tris(2-phenylquinolinato-N,C 2 ’ ) Iridium(III) (abbreviation: Ir(pq)3), bis(2-phenylquinolinato- N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(pq)2(ac Organometallic iridium complexes with pyridine skeletons such as bis(2,4-difluorophenyl) and Venyl-1,3-oxazolato-N,C 2’ ) Iridium(III) acetylacetoner Ir(dpo)2(acac)), bis{2-[4'-(perfluorophenyl (phenyl)pyridinato-N,C 2’}Iridium(III) acetylacetonate( Abbreviation: Ir(p-PF-ph)2(acac)), bis(2-phenylbenzothiazol -N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(bt)2(a In addition to organometallic iridium complexes such as tris(acetylacetonato)(monophenyl) Anthroline) terbium(III) (abbreviation: Tb(acac)3(Phen)) Among the above, the organometallic iridium complexes having a pyrimidine skeleton are Dium complexes are particularly preferred because they are remarkably excellent in reliability and luminous efficiency.

[0129] Examples of substances having a yellow or red emission peak include diisobutyryl Methanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(II I) (abbreviation: Ir(5mdppm)2(dibm)), bis[4,6-bis(3-methyl Phenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: Ir (5mdppm)2(dpm)), bis[4,6-di(naphthalene-1-yl)pyrimidinyl] Nato](dipivaloylmethanato)iridium(III) (abbreviation: Ir(d1npm)2( Organometallic iridium complexes with pyrimidine skeletons such as (acetylacetamide) Iridium(III) r(tppr)2(acac)), bis(2,3,5-triphenylpyrazine)(dipyridine) Valoylmethanato)iridium(III) (abbreviation: Ir(tppr)2(dpm)), ( Acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]i Ir(Fdpq)2(acac) and other pyrazine-based compounds Organometallic iridium complexes and tris(1-phenylisoquinolinato-N,C 2’ ) Iridium(III) (abbreviation: Ir(piq)3), bis(1-phenylisoquinolinato -N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(piq)2( In addition to organometallic iridium complexes with pyridine skeletons such as acac), 2,3,7, 8,12,13,17,18-Octaethyl-21H,23H-porphyrin platinum(II) ) (abbreviation: PtOEP) and tris(1,3-diphenyl-1,3-propanediol). Dopanedionato)(monophenanthroline)europium(III)(abbreviation:Eu(DB 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 with pyrimidine skeletons are Organometallic iridium complexes having the above structure are particularly preferred because they are extremely reliable and have excellent luminous efficiency. In addition, organometallic iridium complexes with pyrazine skeletons can emit red light with good chromaticity. can be done.

[0130] The light-emitting material contained in the light-emitting layer 130 is a material capable of converting triplet excitation energy into light emission. As a material capable of converting the triplet excitation energy into light emission, a phosphorescent material is preferable. In addition to the thermally activated delayed fluorescence compounds, Therefore, phosphorescence The term "thermally activated delayed fluorescent material" may be read as "thermally activated delayed fluorescent material." Thermally activated delayed fluorescent materials are materials that have triplet and singlet excited energy levels. The difference between the triplet excited state and the singlet excited state is small, and reverse intersystem crossing transfers energy from the triplet excited state to the singlet excited state. Therefore, it is possible to convert the triplet excited state into a small amount of thermal energy. Therefore, upconversion (reverse intersystem crossing) to a singlet excited state is possible. In addition, thermally activated delayed fluorescence can be efficiently obtained. The conditions for this are the energies of the triplet excited energy level and the singlet excited energy level. The difference is preferably greater than 0 eV and not greater than 0.2 eV, and more preferably greater than 0 eV and not greater than 0 The optical density is 0.1 eV or less.

[0131] When the thermally activated delayed fluorescent material is composed of one kind of material, for example, the following material is used: It is possible.

[0132] First, fullerene and its derivatives, acridine derivatives such as proflavine, and eosin are listed. In addition, magnesium (Mg), zinc (Zn), cadmium (Cd), tin (S n), platinum (Pt), indium (In), or palladium (Pd) Examples of the metal-containing porphyrin include protoporphyrin. Porphyrin-tin fluoride complex (SnF2(Proto IX)), mesoporphyrin-fluoride Tin complex (SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (Sn F2 (Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride Complex (SnF2(Copro III-4Me)), Octaethylporphyrin-fluoride Tin complex (SnF2(OEP)), etioporphyrin-tin fluoride complex (SnF2(E tio I)), octaethylporphyrin-platinum chloride complex (PtCl2OEP), etc. Can be obtained.

[0133] In addition, as a thermally activated delayed fluorescent material composed of one kind of material, π-electron-rich heteroaromatic Heterocyclic compounds having an aromatic ring and a π-electron deficient heteroaromatic ring can also be used. is 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3- a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol PC CzPTzn), 2-[4-(10H-phenoxazin-10-yl)phenyl]-4, 6-Diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5- Phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl PPZ-3TPT, 3-(9,9-dimethyl- 9H-Acridine-10-yl)-9H-xanthen-9-one (Abbreviation: ACRXTN) , bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10'H-spiro[acridine -9,9'-anthracene]-10'-one (abbreviation: ACRSA), etc. Since the heterocyclic compound has a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring, Among them, a skeleton having a π-electron-deficient heteroaromatic ring is preferable because it has high transport properties and hole transport properties. Among them, diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton) or triazine skeleton The azine skeleton is preferred because it is stable and reliable. Among the skeletons that have this structure, the acridine skeleton, the phenoxazine skeleton, the thiophene skeleton, and the furan skeleton are Since the pyrrole skeleton and the pyrrole skeleton are stable and reliable, any one of these skeletons can be used. It is preferable that the pyrrole skeleton has one or more of the following: skeleton, carbazole skeleton, and 3-(9-phenyl-9H-carbazol-3-yl)- In addition, a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring are particularly preferable. The substance in which the heteroaromatic ring is directly bonded to the π-electron-rich heteroaromatic ring exhibits the donor property of the π-electron-deficient heteroaromatic ring. The acceptor properties of the heteroaromatic rings are both strong, and the energy levels of the singlet excited state and triplet excited state are This is particularly preferred since the difference between the energy level of the excited state and the energy level of the excited state is small.

[0134] In addition, in the light-emitting layer 130, materials other than the host material 131 and the guest material 132 are It is acceptable to have one.

[0135] The material that can be used for the light-emitting layer 130 is not particularly limited, but examples thereof include anthracene, Helicene derivatives, phenanthrene derivatives, pyrene derivatives, chrysene derivatives, dibenzo[g, p]chrysene derivatives and other condensed polycyclic aromatic compounds. Phenylanthracene (abbreviation: DPAnth), 6,12-dimethoxy-5,11-diphenyl Nilcrysene, 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: D PPA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 2-tert -Butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 9, 9'-Bianthryl (abbreviation: BANT), 9,9'-(stilbene-3,3'-diyl) Diphenanthrene (abbreviation: DPNS), 9,9'-(stilbene-4,4'-diyl)di Phenanthrene (abbreviation: DPNS2), 1,3,5-tri(1-pyrenyl)benzene (abbreviation Among these and other known substances, the above A singlet or triplet excited energy level higher than the excited energy level of the guest material 132 One or more substances having an excitation energy level may be selected and used.

[0136] In addition, a compound having a heteroaromatic skeleton, such as an oxadiazole derivative, may be used as the light-emitting layer 1. 30. Specifically, for example, 2-(4-biphenylyl)-5-(4 -tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD) and 1 ,3-Bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazole- 2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-o 4,5-Diphenyl-2-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 4'-Bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs) and the like heterocyclic compounds.

[0137] In addition, metal complexes having heterocycles (e.g., zinc and aluminum-based metal complexes) emit light. For example, quinoline ligands, benzoquinoline ligands, oxo Examples of such metal complexes include those having a thazole ligand or a thiazole ligand. For example, tris(8-quinolinolato)aluminum(III) (abbreviation: Alq), tris Bis(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq3), BeBq2 ), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum ( III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq) Metal complexes having a quinoline skeleton or a benzoquinoline skeleton, such as: In addition, bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnP BO), bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnB Metal complexes with oxazole or thiazole ligands such as TZ are also used. It is possible.

[0138] The light-emitting layer 130 may be formed of two or more layers. When the light-emitting layer 130 is formed by laminating the first light-emitting layer and the second light-emitting layer in this order from the hole transport layer side, A substance having a hole transporting property is used as a host material for the first light-emitting layer, and a substance having a hole transporting property is used as a host material for the second light-emitting layer. In addition, a structure in which a substance having an electron transporting property is used as the first light-emitting layer and the second light-emitting layer is also available. The light-emitting materials in the light-emitting layer and the light-emitting layer may be the same or different materials, and the light-emitting layers may emit the same color light. Even if the material has a function of emitting light, it may have a function of emitting light of different colors. The two light-emitting layers may each contain light-emitting materials that emit light of different colors. By using each of these layers, multiple lights can be obtained simultaneously. It is preferable to select a light-emitting material for each light-emitting layer so that the light emitted from the light-emitting layer becomes white.

[0139] The light-emitting layer 130 can be formed by a deposition method (including a vacuum deposition method), an ink-jet method, a coating method, a grating method, or the like. It can be formed by a method such as rabia printing. In addition to the above-mentioned materials, quantum dots, etc. Even if the inorganic compound or polymer compound (oligomer, dendrimer, polymer, etc.) good.

[0140] <Hole injection layer> The hole injection layer 111 is configured to inject holes from one of the pair of electrodes (electrode 101 or electrode 102). It has a function of promoting hole injection by reducing the injection barrier, and has, for example, electron accepting properties Formed from transition metal oxides, phthalocyanine derivatives, aromatic amines, heteropolyacids, etc. The transition metal oxides include titanium oxide, vanadium oxide, tantalum oxide, Molybdenum oxide, Tungsten oxide, Rhenium oxide, Ruthenium oxide, Chromic acid Examples of the transition metal oxide include zirconium oxide, hafnium oxide, and silver oxide. The oxide has excellent electron-accepting properties and can be easily formed into a film by vacuum deposition or wet deposition. As the phthalocyanine derivative, phthalocyanine and metal phthalocyanine are preferable. Aromatic amines include benzidine derivatives and phenylenediamine derivatives. Polymer compounds such as polythiophene and polyaniline can also be used. For example, the self-doped polythiophene poly(ethylenedioxythiophene ) / poly(styrenesulfonic acid) are typical examples. , phosphomolybdic acid, phosphotungstic acid, silicomolybdic acid, silicotungstic acid, etc. Heteropolyacids and polymer compounds can be easily formed into films by a wet method. This is preferable.

[0141] The hole injection layer 111 is made of the above-mentioned low refractive index hole transport material and the above-mentioned electron transport material. It is preferable to use a layer having a composite material that exhibits receptivity. By this, it is possible to form a layer having a low refractive index while having hole injection / transport properties. As organic materials having a high solubility, TCNQ, F4TCNQ, and F6TCNNQ are preferably used. In addition, a layer containing a material exhibiting electron accepting properties and a layer containing a material having hole transporting properties can be stacked. Charges can be exchanged between these materials in a steady state or in the presence of an electric field. It is possible. Organic materials that exhibit electron-accepting properties include the above-mentioned TCNQ, F4TCNQ, and F6 In addition to TCNNQ, quinodimethane derivatives, chloranil derivatives, hexaazatriphenyl Examples of organic acceptors include chloranil, 2, 3,6,7,10,11-Hexacyano-1,4,5,8,9,12-hexaazatrif Compounds with electron-withdrawing groups (halogen groups or cyano groups) such as phenylene (abbreviation: HAT-CN) Also, transition metals such as titanium, vanadium, tantalum, molybdenum, tantalum, etc. , rhenium, ruthenium, chromium, zirconium, hafnium, silver, etc. with oxygen Specifically, titanium oxide, vanadium oxide, tantalum oxide, etc. Ru oxide, molybdenum oxide, tungsten oxide, rhenium oxide, ruthenium oxide , Chromium oxide, Zirconium oxide, Hafnium oxide, Silver oxide, Phosphomolybdic acid , molybdenum bronze, tungsten bronze, etc. Among them, molybdenum oxide is Among these, it is preferred because it is stable, has low hygroscopicity, and is easy to handle.

[0142] As described above, the hole-transporting material having a low refractive index used in the hole-injection layer 111 is an sp3 Organic compounds with structures in which the conjugation between aromatic rings is broken, such as the bond, and those with bulky substituents Organic compounds having aromatic rings that can be used preferably include those having a structure in which the conjugation between aromatic rings is broken. Examples of the skeleton having such a structure include the above-mentioned tetraarylmethane skeleton and tetraarylsilane skeleton. However, on the other hand, such compounds tend to have poor carrier transport properties. On the other hand, the above-mentioned transition metal and oxygen are not suitable for the hole injection layer. Although the single substance containing ZnO has a very high effect of enhancing hole injection properties, it has a problem of having a high refractive index. However, the above-mentioned transition metal and oxygen-containing materials are considered to be materials that exhibit electron-accepting properties. When used in combination with a hole transport material having a low refractive index for the hole injection layer 111, It was found that the refractive index of 11 can be kept low while ensuring hole injection and transport properties. In other words, this configuration cancels out the disadvantages of both and only brings out the advantages. This is because the electron-accepting properties of materials containing transition metal oxides are high, and the addition of a small amount of them allows for hole injection. This is thought to be due to the fact that it is possible to ensure safety.

[0143] As the hole transporting material, a material having a higher hole transporting property than an electron transporting property can be used. ×10 -6 cm 2 It is preferable that the material has a hole mobility of .lambda. / Vs or more. As described above, the hole transport material preferably has a refractive index of 1 or more and 1.75 or less. It is preferably 1 or more and 1.73 or less, and more preferably 1 or more and 1.70 or less. Specifically, the aromatic amines listed as examples of hole transport materials that can be used in the light-emitting layer 130 are carbazole derivatives, aromatic hydrocarbons, stilbene derivatives, etc. can be used. However, it is particularly preferred that the aromatic ring has a heteroaromatic skeleton containing two or more nitrogen atoms and having 1 to 20 carbon atoms. In addition, the hole transport material may be a polymer compound. good.

[0144] Other examples of hole transport materials include aromatic hydrocarbons, such as 2-tert -Butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 2- tert-Butyl-9,10-di(1-naphthyl)anthracene, 9,10-bis(3, 5-Diphenylphenyl)anthracene (abbreviation: DPPA), 2-tert-butyl-9 ,10-Bis(4-phenylphenyl)anthracene (abbreviation: t-BuDBA), 9,1 0-Di(2-naphthyl)anthracene (abbreviation: DNA), 9,10-diphenylanthracene 2-tert-butylanthracene (abbreviation: DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAn th), 9,10-bis(4-methyl-1-naphthyl)anthracene (abbreviation: DMNA) , 2-tert-butyl-9,10-bis[2-(1-naphthyl)phenyl]anthracene 9,10-bis[2-(1-naphthyl)phenyl]anthracene, 2,3,6,7- Tetramethyl-9,10-di(1-naphthyl)anthracene, 2,3,6,7-tetramethyl 9,10-di(2-naphthyl)anthracene, 9,9'-bianthryl, 10,1 0'-Diphenyl-9,9'-bianthryl, 10,10'-bis(2-phenylphenyl) 10,10'-bis[(2,3,4,5,6-pentafluorophenyl) phenyl)phenyl]-9,9'-bianthryl, anthracene, tetracene, rubrene, perylene, 2,5,8,11-tetra(tert-butyl)perylene, etc. In addition, pentacene, coronene, etc. can also be used. -6 cm 2 / Vs or more, and an aromatic hydrocarbon having 14 to 42 carbon atoms. It is more preferable to use

[0145] The aromatic hydrocarbon may have a vinyl skeleton. Examples of aromatic hydrocarbons include 4,4'-bis(2,2-diphenylvinyl)biphenyl. (abbreviation: DPVBi), 9,10-bis[4-(2,2-diphenylvinyl)phenyl] anthracene (abbreviation: DPVPA), etc.

[0146] Also, 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]fluor phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), 4,4',4''-(phenyl) (1,3,5-phenyl-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), 1,3,5-Tri(dibenzothiophen-4-yl)benzene (abbreviation: DBT3P-II ), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)fluor 4-[4-(9-phenyl)dibenzothiophene (abbreviation: DBTFLP-III), [6-phenyl-9H-fluoren-9-yl]phenyldibenzothiophene (abbreviation :DBTFLP-IV), 4-[3-(triphenylen-2-yl)phenyl]dibenzo Thiophene compounds such as thiophene (abbreviation: mDBTPTp-II), furan compounds, An orene compound, a triphenylene compound, a phenanthrene compound, etc. can be used. Among the above-mentioned compounds, pyrrole skeleton, furan skeleton, thiophene skeleton, aromatic amine skeleton, Compounds having this structure are stable and reliable, and are therefore preferred. The material has a high hole transporting property and contributes to reducing the driving voltage.

[0147] <Hole transport layer> The hole transport layer 112 is a layer containing a hole transporting material. The hole transporting layer 112 is connected to the hole injection layer 111. The HOM of the hole injection layer 111 has a function of transporting the injected holes to the light emitting layer 130. O(Highest Occupied Molecular Orbital) It is preferable for the HOMO level to be the same as or close to the HOMO level (also called occupied orbital level).

[0148] Also, 1×10 -6 cm 2It is preferable that the material has a hole mobility of at least 1 / Vs. However, other substances may be used as long as they have a higher hole transporting property than an electron transporting property. The layer containing a substance having a high hole transporting property may be a single layer or a double layer of the above substance. More than one layer may be laminated.

[0149] ≪Electron transport layer≫ The electron transport layer 118 is connected to the other of the pair of electrodes (electrode 101 or The material has a function of transporting electrons injected from the electrode 102 to the light-emitting layer 130. A material with a higher electron transport capacity than holes can be used as the -6 cm 2 It is preferable that the material has an electron mobility of 100 / Vs or more. As materials with electron transport properties, π-electron-deficient compounds such as nitrogen-containing heteroaromatic compounds are Heteroaromatics and metal complexes can be used. Specifically, the light-emitting layer 130 can be The pyridine derivatives, bipyridine derivatives, and pyrimidine derivatives mentioned above as electron transport materials that can Derivatives, triazine derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, phenazine derivatives Intralin derivatives, triazole derivatives, benzimidazole derivatives, oxadiazole Derivatives thereof include those having a heteroaromatic skeleton having 1 to 20 carbon atoms and containing two or more nitrogen atoms. In particular, compounds having a pyrimidine skeleton and a triazine skeleton are preferred. Also, 1×10 -6 cm 2 It is preferable that the material has an electron mobility of 0.1 V or more. In addition, any other substance than the above may be used as the electron transporting substance as long as it has a higher electron transporting property than the hole transporting property. The electron transport layer 118 may be formed not only as a single layer, but also as the above-mentioned material. Two or more layers of the material may be laminated.

[0150] Also included are metal complexes having heterocycles, such as quinoline ligands and benzoquinoline ligands. Metal complexes having oxazole, thiazole or thiol ligands are also included. Specifically, for example, tris(8-quinolinolato)aluminum(III) (abbreviation: A lq), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Al mq3), bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation :BeBq2), Bis(2-methyl-8-quinolinolato)(4-phenylphenolato)a Aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Metal complexes having a quinoline or benzoquinoline skeleton, such as Znq In addition, bis[2-(2-benzoxazolyl)phenolato]zinc(II) ( Abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phenolato]zinc(II)( Metal complexes with oxazole or thiazole ligands such as ZnBTZ Also, the following can be used.

[0151] In addition, a layer for controlling the movement of electron carriers is provided between the electron transport layer 118 and the light emitting layer 130. This is a material having a high electron transporting property and a material having a high electron trapping property. A layer in which a small amount of Zn is added, which suppresses the movement of electron carriers, thereby reducing carrier dispersion. This structure allows the electron transport property of the electron transport material to be adjusted. Problems that occur when the hole transporting property of the hole transporting material is significantly higher than that of the hole transporting material (e.g., shortening of device life). It is highly effective in suppressing

[0152] ≪Electron injection layer≫ The electron injection layer 119 promotes electron injection by reducing the electron injection barrier from the electrode 102. For example, Group 1 metals, Group 2 metals, or their oxides and halides In addition, the above-mentioned electron transporting material and the corresponding electron A composite material of a material exhibiting electron donating properties can also be used. Examples of the metal include Group 1 metals, Group 2 metals, and oxides thereof. Lithium fluoride (LiF), sodium fluoride (NaF), and cesium fluoride (CsF ), calcium fluoride (CaF2), lithium oxide (LiO x ) and other alkaline gold Metals, alkaline earth metals, or compounds thereof can be used. A rare earth metal compound such as fluorine (ErF3) can be used. An electride may be used for 119. The electride may be, for example, calcium. Examples include a material in which electrons are highly concentrated in a mixed oxide of aluminum and ruthenium. The injection layer 119 may be made of a material that can be used in the electron transport layer 118 .

[0153] In addition, the electron injection layer 119 is made of a composite material obtained by mixing an organic compound and an electron donor. Such composite materials may be made by adding electrons to an organic compound via an electron donor. In this case, the organic compound is It is preferable that the material has excellent transport properties for the generated electrons. Specifically, for example, the above-mentioned The material constituting the electron transport layer 118 (metal complex, heteroaromatic compound, etc.) can be used. The electron donor may be any substance that exhibits electron donating properties to organic compounds. For the metal, alkali metals, alkaline earth metals and rare earth metals are preferred, and lithium, sodium , cesium, magnesium, calcium, erbium, ytterbium, etc. In addition, alkali metal oxides and alkaline earth metal oxides are preferred, and lithium oxide, calcium oxide, etc. Examples of the oxides include magnesium oxide, barium oxide, etc. A base can also be used. In addition, organic compounds such as tetrathiafulvalene (TTF) can be used. You can also use things.

[0154] The above-mentioned light-emitting layer, hole injection layer, hole transport layer, electron transport layer, and electron injection layer are These methods include deposition (including vacuum deposition), inkjet, coating, and gravure printing. The light-emitting layer, the hole-injecting layer, the hole-transporting layer, the electron In addition to the above-mentioned materials, the transport layer and the electron injection layer may be made of inorganic compounds such as quantum dots or high molecular weight compounds. A polymer compound (oligomer, dendrimer, polymer, etc.) may also be used.

[0155] ≪Quantum dots≫ Quantum dots are semiconductor nanocrystals with sizes ranging from a few nm to a few tens of nm, and are on the order of 1×10 3 Individual to 1×10 6 Quantum dots are composed of about 100 atoms. The energy of quantum dots depends on their size. Therefore, even if quantum dots are made of the same material, the emission wavelengths change depending on the size. Therefore, by changing the size of the quantum dots used, light emission can be easily The wavelength can be changed.

[0156] In addition, quantum dots have a narrow emission spectrum peak width, so they can emit light with good color purity. Furthermore, the theoretical internal quantum efficiency of quantum dots is said to be nearly 100%. This is much higher than the 25% of organic compounds that emit fluorescent light, and the 15% of organic compounds that emit phosphorescent light. This means that quantum dots can be used as light-emitting materials. In addition, quantum dots, which are inorganic materials, can be used to obtain light-emitting devices with high luminous efficiency. Since the intrinsic stability is also excellent, a light-emitting device that is preferable in terms of life can be obtained. This can be done.

[0157] The materials that make up quantum dots include elements from Group 14, Group 15, Group 16, and Compounds consisting of several Group 14 elements, and compounds consisting of elements belonging to Groups 4 to 14 and Group 16 elements Compounds, compounds of Group 2 elements and Group 16 elements, compounds of Group 13 elements and Group 15 elements , compounds of Group 13 and Group 17 elements, compounds of Group 14 and Group 15 elements, Compounds of group 11 and group 17 elements, iron oxides, titanium oxides, chalcogenide spinel Examples of the semiconductor clusters include:

[0158] Specifically, cadmium selenide, cadmium sulfide, cadmium telluride, and sulfur selenide Lead, zinc oxide, zinc sulfide, zinc telluride, mercury sulfide, mercury selenide, mercury telluride, arsenide Indium, indium phosphide, gallium arsenide, gallium phosphide, indium nitride, nitride Gallium, indium antimonide, gallium antimonide, aluminum phosphide, arsenide Aluminum, Aluminum antimonide, Lead selenide, Lead telluride, Lead sulfide, Lead selenide Indium, indium telluride, indium sulfide, gallium selenide, arsenic sulfide, selenium arsenic nitride, arsenic telluride, antimony sulfide, antimony selenide, antimony telluride, Bismuth sulfide, bismuth selenide, bismuth telluride, silicon, silicon carbide, germanium Aluminum, tin, selenium, tellurium, boron, carbon, phosphorus, boron nitride, boron phosphide, boron arsenide , aluminum nitride, aluminum sulfide, barium sulfide, barium selenide, barium telluride Lithium, Calcium Sulfide, Calcium Selenide, Calcium Telluride, Beryllium Sulfide, Beryllium selenide, Beryllium telluride, Magnesium sulfide, Magnesium selenide, Germanium sulfide, Germanium selenide, Germanium telluride, Tin sulfide, Tin selenide , tin telluride, lead oxide, copper fluoride, copper chloride, copper bromide, copper iodide, copper oxide, copper selenide, acid Nickel oxide, cobalt oxide, cobalt sulfide, iron oxide, iron sulfide, manganese oxide, molyb sulfide tantalum oxide, titanium oxide, zirconium oxide, vanadium oxide, tungsten oxide, tantalum oxide Aluminum, silicon nitride, germanium nitride, aluminum oxide, barium titanate, selenium and zinc Compounds of lead and cadmium, compounds of indium, arsenic and phosphorus, compounds of cadmium, selenium and sulfur Compounds of cadmium, selenium and tellurium, compounds of indium, gallium and arsenic , compounds of indium, gallium and selenium, compounds of indium, selenium and sulfur, compounds of copper and indium Examples of the compounds include indium and sulfur compounds, and combinations of these. In addition, the composition is expressed in any ratio, so-called alloy type quantum dots can be used. For example, alloy quantum dots of cadmium, selenium, and sulfur can be fabricated by changing the ratio of the elements. This is one of the effective methods to obtain blue light emission because the emission wavelength can be changed by It is one.

[0159] Quantum dot structures include core type, core-shell type, and core-multishell type. Either of these can be used, but it is also advisable to cover the core with another inorganic material with a wider band gap. By forming a shell of material, defects and dangling bonds on the nanocrystal surface can be eliminated. This greatly improves the quantum efficiency of light emission, It is preferable to use core-shell or core-multishell quantum dots. Examples of materials include zinc sulfide and zinc oxide.

[0160] In addition, quantum dots have a high proportion of surface atoms, making them highly reactive and less prone to aggregation. Therefore, a protective agent or a protective group is attached to the surface of the quantum dots. It is preferable that the protecting agent is attached or the protecting group is provided. It is possible to prevent aggregation and increase solubility in solvents. It is also possible to reduce reactivity and electrically It is also possible to improve stability. Examples of the protecting agent (or protecting group) include poliovirus. Polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene Polyoxyethylene alkyl ethers such as ethylene oleyl ether, tripropyl phosphatase phosphine, tributylphosphine, trihexylphosphine, trioctylphosphine, etc. Trialkylphosphines, polyoxyethylene n-octylphenyl ether, polyoxyethylene Polyoxyethylene alkylphenyl ethers such as oxyethylene n-nonylphenyl ether amine, tri(n-hexyl)amine, tri(n-octyl)amine, tri(n-decyl)amine ) tertiary amines such as amine, tripropylphosphine oxide, tributylphosphine Oxide, trihexylphosphine oxide, trioctylphosphine oxide, tridecylphosphine oxide Organic phosphorus compounds such as silylphosphine oxide, polyethylene glycol dilaurate, polyethylene glycol diesters such as polyethylene glycol distearate, Organic nitrogen compounds such as pyridine, lutidine, collidine, quinolines, and other nitrogen-containing aromatic compounds , hexylamine, octylamine, decylamine, dodecylamine, tetradecylamine aminoalkanes such as dibutylsulfide, hexadecylamine, and octadecylamine; dialkyl sulfides such as dimethyl sulfoxide and dibutyl sulfoxide; organic sulfur compounds such as alkyl sulfoxides, sulfur-containing aromatic compounds such as thiophene, palmitic acid compounds, etc. Higher fatty acids such as acetic acid, stearic acid, and oleic acid, alcohols, sorbitan fatty acid esters, esters, fatty acid modified polyesters, tertiary amine modified polyurethanes, polyethylene Examples of such compounds include amines.

[0161] As quantum dots become smaller, their band gaps become larger, so the desired wavelengths can be obtained. The size of the crystal is adjusted accordingly to obtain long-range light. As a result, the emission of quantum dots is shifted to the blue side, i.e., to the higher energy side. By changing the size of the filter, wavelengths in the ultraviolet, visible, and infrared regions of the spectrum can be obtained. The emission wavelength can be tuned over a range of wavelengths. The size (diameter) of the quantum dot is Generally, the range of 0.5 nm to 20 nm, preferably 1 nm to 10 nm, is used. The narrower the size distribution of quantum dots, the narrower the emission spectrum becomes. In addition, the shape of the quantum dots is not particularly limited, and The shape may be a sphere, a rod, a disk, or any other shape. Since the rods have the ability to emit directional light, quantum rods can be used as light-emitting materials. This makes it possible to obtain a light emitting element having better external quantum efficiency.

[0162] In most cases, organic EL devices are made by dispersing a light-emitting material in a host material. The host material is one of the most important materials for the luminescence. The material must have a singlet or triplet excited energy level. In particular, when a blue phosphorescent material is used as the light-emitting material, triplet excitation energy of 100 or more is required. A host material that has a high level and is excellent in terms of lifetime is required, and its development is extremely difficult. Here, the quantum dots are used to form a light-emitting layer without using a host material. Therefore, from the viewpoint of life span, this light-emitting element is also favorable. When the light-emitting layer is formed only from quantum dots, the quantum dots are core- A shell structure (including a core-multishell structure) is preferred.

[0163] When quantum dots are used as the light-emitting material of the light-emitting layer, the thickness of the light-emitting layer is 3 nm to 100 nm. m, preferably 10 nm to 100 nm, and the content of quantum dots in the light-emitting layer is 1 to 1 00% by volume. However, it is preferable to form the light-emitting layer only from quantum dots. In the case where the quantum dots are dispersed in a host as a light-emitting material to form a light-emitting layer, the host material The quantum dots are dispersed in a suitable liquid medium, or the host material and the quantum dots are dissolved or mixed in a suitable liquid medium. Disperse and apply wet processes (spin coating, casting, die coating, blade coating, etc.) Coating method, roll coating method, inkjet method, printing method, spray coating method, curtain coating The phosphorescent material may be formed by a method such as the Langmuir-Blodgett method. For the light-emitting layer using the above, in addition to the wet process, a vacuum deposition method can also be suitably used. This can be done.

[0164] Examples of liquid media used in wet processes include methyl ethyl ketone, cyclohexane, etc. Ketones such as xanone, fatty acid esters such as ethyl acetate, halogens such as dichlorobenzene Hydrocarbons, aromatics such as toluene, xylene, mesitylene, and cyclohexylbenzene Hydrocarbons, aliphatic hydrocarbons such as cyclohexane, decalin, and dodecane, dimethylformamide, etc. Organic solvents such as dichloromethane (DMF) and dimethyl sulfoxide (DMSO) can be used. Cut.

[0165] The electrode 101 and the electrode 102 function as an anode or a cathode of the light-emitting element. The electrode 101 and the electrode 102 may be made of a metal, an alloy, a conductive compound, or a mixture or laminate of these. It can be formed using the above.

[0166] One of the electrodes 101 and 102 is made of a conductive material that has a function of reflecting light. The conductive material is preferably aluminum (Al) or a composite material containing Al. Examples of alloys containing Al include Al and L (L is titanium (Ti), neodymium (Nd)). (representing one or more of Nd, Ni, and La) Examples of the alloy include an alloy containing Al and Ti, or an alloy containing Al, Ni and La. Aluminum has low resistance and high light reflectance. Since aluminum is abundant and inexpensive, the manufacturing cost of light-emitting elements using aluminum is low. In addition, silver (Ag) or Ag and N (N is yttrium ( Y), Nd, Magnesium (Mg), Ytterbium (Yb), Al, Ti, Gallium ( Ga), zinc (Zn), indium (In), tungsten (W), manganese (Mn), Tin (Sn), iron (Fe), Ni, copper (Cu), palladium (Pd), iridium (Ir ), or an alloy containing gold (Au), etc. Examples of alloys that can be used include alloys containing silver, palladium, and copper, alloys containing silver and copper, and alloys containing silver and magnesium. Alloys containing nesium, alloys containing silver and nickel, alloys containing silver and gold, and silver and ytterbium Other examples include alloys containing tungsten, chromium (Cr), molybdenum (Mo ), copper, titanium, and other transition metals can be used.

[0167] The light emitted from the light-emitting layer is emitted through one or both of the electrodes 101 and 102. Therefore, at least one of the electrodes 101 and 102 is transparent to light. It is preferable that the conductive material is a material having a permeability function. The visible light transmittance is 40% or more and 100% or less, preferably 60% or more and 100% or less, The resistivity is 1×10 -2 Examples include conductive materials with a resistance of Ω·cm or less.

[0168] In addition, the electrodes 101 and 102 have a function of transmitting light and a function of reflecting light. The conductive material may be formed of a conductive material having a visible light reflectance of 20 or more. % or more and 80% or less, preferably 40% or more and 70% or less, and the resistivity is 1×10 -2 Conductive materials with a capacitance of Ω·cm or less include conductive metals, alloys, and conductive materials. The insulating layer can be formed by using one or more of the following compounds: Indium Tin Oxide (ITO), silicon or silicon oxide Indium tin oxide (ITSO), indium oxide-zinc oxide (Indium um Zinc Oxide), titanium-containing indium tin oxide, indium Metals such as indium oxide containing titanium oxide, tungsten oxide, and zinc oxide Oxides can be used. In addition, the thickness of the oxide is preferably within a range of 1 nm to 30 nm. A metal thin film having a thickness of 1 μm or less can be used. Examples of metals include Ag, Alloys such as Ag and Al, Ag and Mg, Ag and Au, and Ag and Yb can be used.

[0169] In this specification and the like, a material having a function of transmitting light is a material having a function of transmitting visible light. Any material having the above and having electrical conductivity may be used, and examples thereof include ITO. In addition to oxide conductors, oxide semiconductors and organic conductors containing organic substances are also included. The organic conductor containing the electron donor is, for example, a mixture of an organic compound and an electron donor. Examples of such materials include composite materials made by mixing organic compounds and electron acceptors. Alternatively, an inorganic carbon-based material such as graphene may be used. The rate is preferably 1×10 5 Ω cm or less, more preferably 1×10 4 Ω cm The following is the result.

[0170] In addition, by laminating a plurality of the above materials, one or both of the electrodes 101 and 102 can be formed. may form both.

[0171] In order to improve the light extraction efficiency, the electrode is in contact with the light transmitting electrode. A material having a higher refractive index than the electrode may be used. As long as the material has the function of providing the above, it may be a material that is conductive or not. For example, in addition to the oxide conductors described above, oxide semiconductors and organic materials can be used. The organic material may be, for example, a light-emitting layer, a hole-injecting layer, a hole-transporting layer, an electron-transporting layer, or an electron The materials listed for the electron injection layer are also available. Inorganic carbon-based materials and metals that are light-transmitting are also available. A thin film may also be used, and multiple layers of several nanometers to several tens of nanometers may be laminated.

[0172] When the electrode 101 or the electrode 102 functions as a cathode, the work function is small. (3.8 eV or less) materials. For example, Elements in the group (alkali metals such as lithium, sodium, and cesium, calcium, strontium, etc.) Alkaline earth metals such as rontium, magnesium, etc.), alloys containing these elements (e.g., Rare earth metals such as Ag and Mg, Al and Li, europium (Eu), Yb, etc. An alloy containing a metal, such as an alloy containing aluminum or silver, can be used.

[0173] In addition, when the electrode 101 or the electrode 102 is used as an anode, the electrode having a large work function (4. 0 eV or more) materials are preferably used.

[0174] The electrodes 101 and 102 are made of a conductive material having a function of reflecting light and a conductive material having a function of transmitting light. In this case, the electrode 101 and the electrode 102 may be laminated with a conductive material having a permeability function. 02 can resonate light of a desired wavelength from each light-emitting layer and intensify the light of the desired wavelength. This is preferable because it has a function of adjusting the optical path length so that the optical path length can be adjusted.

[0175] The electrode 101 and the electrode 102 are formed by a method such as sputtering, vapor deposition, printing, or coating. , MBE (Molecular Beam Epitaxy) method, CVD method, pulse laser The deposition method, ALD (Atomic Layer Deposition) method, etc. are used appropriately. It is possible.

[0176] <Substrate> In addition, the light-emitting element according to one embodiment of the present invention is provided on a substrate made of glass, plastic, or the like. Regarding the order of fabrication on the substrate, the layers may be stacked in order from the electrode 101 side. They may be laminated in order from the pole 102 side.

[0177] The substrate on which the light-emitting element according to one embodiment of the present invention can be formed is, for example, glass or quartz. A flexible substrate may be used. The substrate is a flexible substrate, such as polycarbonate. Examples of suitable substrates include plastic substrates made of polyacrylates and polyarylates. Inorganic deposition films and the like can also be used. Any other material may be used as long as it functions as a support in the development. Anything that has the function of protecting the optical elements and the light elements may be used.

[0178] For example, in the present invention, a light emitting element can be formed using various substrates. The type of the substrate is not particularly limited. An example of the substrate is a semiconductor substrate (e.g., a single crystal substrate or silicon substrate), SOI substrate, glass substrate, quartz substrate, plastic substrate, metal Substrate, stainless steel substrate, substrate with stainless steel foil, tungsten substrate, substrate with tungsten foil, flexible substrate, laminated film, fibrous Examples of glass substrates include barium phosphide-based paper or base films. Examples include borosilicate glass, aluminoborosilicate glass, and soda-lime glass. Examples of the functional substrate, laminate film, base film, etc. are as follows. For example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), Representative examples include polyethersulfone (PES) and polytetrafluoroethylene (PTFE). For example, plastics such as acrylic resins are used. Examples include polypropylene, polyester, polyvinyl fluoride, or polyvinyl chloride. Examples include polyamide, polyimide, aramid, epoxy, and inorganic. Examples include machine-deposited films and papers.

[0179] In addition, a flexible substrate may be used as the substrate, and the light emitting element may be formed directly on the flexible substrate. Alternatively, a release layer may be provided between the substrate and the light-emitting element. After a part or all of a chip is completed, it is separated from the board and used to transfer it to another board. In this case, the light-emitting element can be transferred onto a substrate having poor heat resistance or a flexible substrate. The above-mentioned peeling layer has a laminated structure of inorganic films, for example, a tungsten film and a silicon oxide film. or a structure in which a resin film such as polyimide is formed on a substrate.

[0180] That is, a light emitting element is formed using a certain substrate, and then the light emitting element is transferred to another substrate. The light emitting element may be disposed on another substrate. In addition to the above mentioned substrates, cellophane substrates, stone substrates, wood substrates, fabric substrates (natural fibers (silk, cotton, Hemp), synthetic fibers (nylon, polyurethane, polyester) or regenerated fibers (acetate (including cellulose, cupra, rayon, recycled polyester, etc.), leather substrate, rubber substrate, etc. By using these substrates, light-emitting elements that are not easily broken and have high heat resistance can be produced. The light emitting element may be a small light emitting element, a light emitting element that is lighter in weight, or a light emitting element that is thinner.

[0181] Also, for example, a field effect transistor (FET) is formed on the above-mentioned substrate, and the FET and The light emitting element 150 may be fabricated on the electrically connected electrodes. In this way, an active matrix display device that controls the driving of the light emitting element 150 can be manufactured.

[0182] The components of a solar cell, which is an example of an electronic device according to one embodiment of the present invention, will be described below. Do the following.

[0183] The materials that can be used in the light-emitting element described above can be used in the solar cell. The carrier transport layer of the pond is made of the hole transport material and the electron transport material described above, and the photovoltaic layer is made of The above-mentioned hole transport material, electron transport material, light emitting material, silicon, CH3NH3PbI Perovskite crystals such as those shown in Fig. 3 can be used. In addition, regarding the substrate and electrodes, The above-mentioned materials that can be used for the light-emitting element can also be used.

[0184] The structure shown in this embodiment mode can be used in appropriate combination with other embodiment modes. Cut.

[0185] (Embodiment 2) In this embodiment mode, a light-emitting element having a different structure from that of the light-emitting element shown in Embodiment 1 is used. The light emitting mechanism of the light emitting device will be described below with reference to FIGS. 3 and 4, the same reference numerals as those in FIG. 2(A) denote the same parts having the same functions. In some cases, the symbols are omitted and hatched patterns are used. Also, parts with similar functions are indicated by Similar reference symbols are used and detailed descriptions thereof may be omitted.

[0186] <Configuration example 1 of light-emitting element> FIG. 3A is a schematic cross-sectional view of a light-emitting element 250. FIG.

[0187] The light-emitting element 250 shown in FIG. 3A has a pair of electrodes (electrodes 101 and 102) between which , a plurality of light-emitting units (in FIG. 3A, light-emitting unit 106 and light-emitting unit 1 In the light-emitting element 250, the electrode 101 functions as an anode, and the electrode The following description will be given assuming that 102 functions as a cathode, but the configuration of the light-emitting element 250 is as follows: The opposite is also fine.

[0188] In the light-emitting element 250 shown in FIG. 3A, the light-emitting unit 106 and the light-emitting unit 108 are stacked on top of each other, and a charge is provided between the light-emitting unit 106 and the light-emitting unit 108. The light-emitting unit 106 and the light-emitting unit 108 have the same structure. The configuration may be different.

[0189] The light emitting element 250 includes a light emitting layer 120 and a light emitting layer 170. In addition to the light-emitting layer 170, the knit 106 includes a hole injection layer 111, a hole transport layer 112, an electron transport The light-emitting unit 108 also includes an emissive layer 120. In addition to the above, a hole injection layer 116, a hole transport layer 117, an electron transport layer 118, and an electron injection layer 11 Has 9.

[0190] The charge generating layer 115 is formed by adding an acceptor material, which is an electron acceptor, to a hole transporting material. Even if the structure is such that the electron transport material is a material having a donor property, the structure may be such that the donor property is added to the electron transport material. In addition, both of these configurations may be laminated.

[0191] When the charge generating layer 115 contains a composite material of an organic compound and an acceptor substance, As the composite material, the composite material which can be used for the hole-injection layer 111 shown in Embodiment 1 is used. The organic compounds include aromatic amine compounds, carbazole compounds, aromatic carbon compounds, etc. Various compounds such as hydrogen and polymer compounds (oligomers, dendrimers, polymers, etc.) are used. As an organic compound, a hole mobility of 1×10 -6 cm 2 / Vs However, it is preferable to use a substance having a higher hole transporting property than an electron transporting property. Other materials may be used as long as they are compatible with the organic compound and the acceptor material. The material has excellent carrier injection and transport properties, enabling low-voltage and low-current operation. In addition, the anode side surface of the light-emitting unit is in contact with the charge generating layer 115. In this case, the charge generating layer 115 also serves as a hole injection layer or a hole transport layer for the light emitting unit. Therefore, the light-emitting unit does not need to have a hole injection layer or a hole transport layer. Alternatively, when the cathode side surface of the light-emitting unit is in contact with the charge generating layer 115, The charge generating layer 115 also serves as an electron injection layer or an electron transport layer for the light emitting unit. Therefore, the light-emitting unit does not have an electron injection layer or an electron transport layer. is also good.

[0192] The charge generating layer 115 may be a layer including a composite material of an organic compound and an acceptor substance. For example, the organic EL element may be formed as a laminated structure in which layers made of the organic material are combined. A layer including a composite material of a compound and an acceptor material, and a layer including a compound selected from an electron donor material. The compound may be combined with a compound having a high electron transporting property to form a layer. A layer including a composite material of an organic compound and an acceptor substance and a layer including a transparent conductive film are combined. It may be formed by combining the above.

[0193] The charge generating layer 115 sandwiched between the light emitting unit 106 and the light emitting unit 108 is When a voltage is applied between the electrode 101 and the electrode 102, electrons are injected into one of the light-emitting units, It is sufficient if the hole is injected 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, The charge generating layer 115 injects electrons into the light-emitting unit 106 and holes into the light-emitting unit 108. Enter.

[0194] From the viewpoint of light extraction efficiency, the charge generating layer 115 is required to be transparent to visible light (specifically, It is preferable that the charge generating layer 115 has a visible light transmittance of 40% or more. In addition, the charge generating layer 115 has a lower electrical conductivity than the pair of electrodes (the electrodes 101 and 102). But it still works.

[0195] When the charge generating layer 115 is formed using the above-mentioned material, the light emitting layer is laminated. In this case, the increase in the driving voltage can be suppressed.

[0196] In addition, in FIG. 3A, a light-emitting element having two light-emitting units has been described. However, the same can be applied to light-emitting devices in which three or more light-emitting units are stacked. As shown in the light-emitting element 250, a plurality of light-emitting units are disposed between a pair of electrodes. By separating the layers, it is possible to achieve high brightness light emission while keeping the current density low. A light-emitting element having a long life and low power consumption can be realized. .

[0197] In each of the above configurations, the guest used for the light-emitting unit 106 and the light-emitting unit 108 The light emitting colors of the light emitting materials may be the same or different. A guest material having a function of emitting light of the same color in the light emitting unit 106 and the light emitting unit 108. In this case, the light emitting element 250 becomes a light emitting element that exhibits high light emission luminance with a small current value, which is preferable. In addition, the light emitting units 106 and 108 emit light of different colors. When the light-emitting device 250 has a guest material having the function of emitting light of multiple colors, the light-emitting device 250 emits light of multiple colors. In this case, either or both of the light-emitting layer 120 and the light-emitting layer 170 are preferably By using a plurality of light-emitting materials having different emission wavelengths, the light emitted by the light-emitting element 250 The spectrum is a composite of light with different emission peaks, so there are at least two The emission spectrum has a maximum value of

[0198] The above-mentioned configuration is also suitable for obtaining white light emission. By making the colors complementary to each other, white light can be obtained. The guest material is selected so as to have a high white emission or at least an emission having red, green and blue colors. It is preferable to select a fee.

[0199] In addition, in the case of a light-emitting element having three or more stacked light-emitting units, the The emission colors of the guest materials may be the same or different. In the case where a plurality of light-emitting units that emit light are included, the emission colors of the plurality of light-emitting units are as follows: Compared to other colors, it is possible to obtain high luminance with a small current value. The composition can be suitably used to adjust the luminous color. This is suitable when using a guest material that exhibits a luminescent color. For example, In this case, two layers of light-emitting units having fluorescent materials of the same color are used, and one layer of light-emitting units having a different luminescent color from the fluorescent materials is used. By forming a light-emitting unit having a phosphorescent material that exhibits fluorescence and phosphorescence in a single layer, the intensity of the fluorescence and phosphorescence can be enhanced. In other words, the intensity of the emitted color can be adjusted by changing the number of light-emitting units. It is Noh.

[0200] In the case of a light-emitting device having two layers of such fluorescent light-emitting units and one layer of a phosphorescent light-emitting unit, It contains two layers of light-emitting units containing color fluorescent materials and one layer of light-emitting unit containing yellow phosphorescent material. A light-emitting element or a light-emitting unit containing a blue fluorescent material is layered, and a red phosphorescent material and a green phosphorescent material are layered. a light-emitting device having one light-emitting layer unit containing a blue fluorescent material, two light-emitting units containing a red fluorescent material, A light-emitting device having one light-emitting layer unit including a phosphorescent material, a yellow phosphorescent material, and a green phosphorescent material. This is preferable because white light can be efficiently emitted.

[0201] In addition, at least one of the light-emitting layer 120 and the light-emitting layer 170 is further divided into layers, Each of the divided layers may contain a different light-emitting material. Alternatively, at least one of the light-emitting layers 170 may be composed of two or more layers. For example, the first light-emitting layer and the second light-emitting layer can be laminated in this order from the hole transport layer side to form the light-emitting layer. In this case, a material having a hole transporting property is used as the host material of the first light-emitting layer, and a material having a hole transporting property is used as the host material of the second light-emitting layer. In this case, a material having an electron transporting property is used as the host material. The light-emitting material in the light-emitting layer and the second light-emitting layer may be the same or different. Even if a material has the function of emitting light of the same color, it may have the function of emitting light of different colors. A plurality of light-emitting materials each having a function of emitting light of a different color may be used. By using this configuration, it is possible to obtain white light with high color rendering properties consisting of the three primary colors or four or more colors. It is also possible.

[0202] At least one of the multiple units has the structure shown in the first embodiment. By applying this structure, a light-emitting device with good light extraction efficiency and reduced driving voltage is provided. It can be provided.

[0203] As shown in FIG. 3B, the light-emitting layer 120 of the light-emitting unit 108 is The light-emitting device includes a guest material 121 and a host material 122. The guest material 121 is a fluorescent material. , as explained below.

[0204] <Light Emitting Mechanism of the Light Emitting Layer 120> The light emitting mechanism of the light emitting layer 120 will be described below.

[0205] The charge injected from a pair of electrodes (electrodes 101 and 102) or the charge generating layer 115 The electrons and holes recombine in the light-emitting layer 120 to generate excitons. Since the host material 122 is present in a large amount compared to the material 121, the generation of excitons causes The excited state of the host material 122 is formed. Note that the excitons are carriers (electrons and holes). ) pair.

[0206] When the excited state of the formed host material 122 is a singlet excited state, the host material 12 The singlet excitation energy is transferred from the S1 level of 2 to the S1 level of the guest material 121. As a result, the singlet excited state of the guest material 121 is formed.

[0207] Since the guest material 121 is a fluorescent material, a singlet excited state occurs in the guest material 121. When the guest material 121 is formed, it quickly emits light. For this purpose, it is preferable that the guest material 121 has a high fluorescence quantum yield. In the case of 1, the same applies when the carriers recombine and the excited state generated is a singlet excited state. It is.

[0208] Next, when the triplet excited state of the host material 122 is formed by carrier recombination, In this case, the energy levels of the host material 122 and the guest material 121 are The correlation between the positions is shown in Figure 3(C). The notations and symbols in Figure 3(C) are as follows: In addition, the T1 level of the host material 122 is lower than the T1 level of the guest material 121. Since this is preferable, FIG. 3C illustrates this case. may be higher than the T1 level of the guest material 121.

[0209] Guest(121): Guest material 121 (fluorescent material) ·Host(122): Host material 122 ·S FG : S1 level of guest material 121 (fluorescent material) T FG : T1 level of guest material 121 (fluorescent material) ·S FH : S1 level of the host material 122 T FH : T1 level of the host material 122

[0210] As shown in Figure 3(C), triplet-triplet annihilation (TTA) The triplet generated by carrier recombination is Excitons interact with each other, transferring excitation energy and exchanging spin angular momentum. As a result, the S1 level (S FH ) energy A reaction occurs in which the host material 122 is converted into a singlet exciton (see Figure 3(C) TTA). The singlet excitation energy of is S FH From the lower energy guest material 121 The S1 level of (S FG ) (see Route E1 in Figure 3(C)), and the guest A singlet excited state of the material 121 is formed, and the guest material 121 emits light.

[0211] In addition, when the density of triplet excitons in the light-emitting layer 120 is sufficiently high (for example, 1×10 12 cm -3 In the above, the deactivation of a single triplet exciton is ignored, and the deactivation of two adjacent triplet excitons is considered. Only the reaction by the child can be considered.

[0212] In addition, when carriers recombine in the guest material 121 to form a triplet excited state, However, the triplet excited state of the guest material 121 is thermally deactivated, making it difficult to utilize it for light emission. However, the T1 level (T FH ) is the T1 equivalent of guest material 121 Place(T FG ), the triplet excitation energy of guest material 121 is lower than that of guest material 1 21 T1 levels (T FG ) to the T1 level (T FH ) Energy transfer (see route E2 in Fig. 3(C)) and then used for TTA.

[0213] That is, the host material 122 converts triplet excitation energy into singlet excitation energy by TTA. It is preferable that the light-emitting layer 120 has a function of converting the generated energy into the light-emitting layer 120. A portion of the triplet excitation energy is converted to singlet excitation energy by TTA in the host material 122. The singlet excitation energy is converted into singlet energy, and the singlet excitation energy is transferred to the guest material 121, thereby producing a fluorescent To achieve this, the S1 level (S FH ) is the S1 level (S FG ) is preferable. The T1 level (T FH ) is the T1 level (T FG ) lower It is preferred.

[0214] In particular, the T1 level (T FG ) is the T1 level of the host material 122 ( T FH ), the weight ratio of the host material 122 to the guest material 121 is In particular, it is preferable that the weight ratio of the guest material 121 is low. The weight ratio of the guest material 121 at this time is preferably greater than 0 and less than or equal to 0.05. This can reduce the probability of carrier recombination in the guest material 121. In addition, the T1 level (T FH ) to the T1 level of the guest material 121 (T FG ) This can reduce the probability of energy transfer to the

[0215] The host material 122 may be composed of a single compound or a plurality of compounds. It may be formed.

[0216] In addition, the light-emitting units 106 and 108 have guest materials that emit light of different colors. In this case, the emission from the light-emitting layer 120 has a peak in the shorter wavelength side than the emission from the light-emitting layer 170. It is preferable to use a material having a high triplet excitation energy level. The light-emitting element used in this study tends to have a tendency to deteriorate in luminance quickly. By using TA, it is possible to provide a light-emitting element with little deterioration in luminance.

[0217] <Light-emitting element configuration example 2> FIG. 4A is a schematic cross-sectional view of the light emitting element 252. FIG.

[0218] The light emitting element 252 shown in FIG. 4A has a pair of electrodes, similar to the light emitting element 250 shown above. A plurality of light-emitting units (light-emitting elements in FIG. 4A) are disposed between the electrodes 101 and 102. At least one of the light-emitting units is The light-emitting unit 106 and the light-emitting unit 110 have the same structure as the EL layer 100. may be of the same or different configurations.

[0219] In addition, in the light-emitting element 252 shown in FIG. 4A, the light-emitting unit 106 and the light-emitting unit The light-emitting unit 106 and the light-emitting unit 110 are laminated, and a charge generating layer is formed between the light-emitting unit 106 and the light-emitting unit 110. For example, the EL layer 100 is preferably used for the light-emitting unit 106. It is nice.

[0220] The light emitting element 252 includes a light emitting layer 140 and a light emitting layer 170. In addition to the light-emitting layer 170, the knit 106 includes a hole injection layer 111, a hole transport layer 112, an electron transport The light-emitting unit 110 also includes an emissive 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 Has 9.

[0221] In addition, at least one of the multiple units is By applying the above configuration, a light-emitting device having good light extraction efficiency and reduced driving voltage can be obtained. can be provided.

[0222] The light-emitting layer 140 of the light-emitting unit 110 is composed of a guest material 1 as shown in FIG. The host material 142 includes an organic compound 142_ The light-emitting layer 140 includes a guest material 141 and an organic compound 142_2. 1 is a phosphorescent material, which will be described below.

[0223] <Light Emitting Mechanism of the Light Emitting Layer 140> Next, the light emitting mechanism of the light emitting layer 140 will be described below.

[0224] The organic compound 142_1 and the organic compound 142_2 in the light-emitting layer 140 form an exciplex. Form.

[0225] The combination of organic compound 142_1 and organic compound 142_2 forms an exciplex with each other. Any combination that can form a hole transporting compound is acceptable. It is more preferable that the other is a compound having an electron transporting property.

[0226] The organic compound 142_1, the organic compound 142_2, and the guest material in the light-emitting layer 140 The correlation between the energy levels of 141 and 142 is shown in FIG. 4(C). The symbols and symbols are as follows:

[0227] Guest(141): Guest material 141 (phosphorescent material) ·Host(142_1): Organic compound 142_1 (host material) ·Host(142_2): Organic compound 142_2 (host material) T PG :T1 level of guest material 141 (phosphorescent material) ·S PH1 : S1 level of organic compound 142_1 (host material) T PH1 :T1 level of organic compound 142_1 (host material) ·S PH2 : S1 level of organic compound 142_2 (host material) T PH2 :T1 level of organic compound 142_2 (host material) ·S PE : S1 level of the exciplex T PE :T1 level of the exciplex

[0228] The organic compound 142_1 and the organic compound 142_2 form an exciplex, and the S 1 level (S PE ) and T1 level (T PE ) are adjacent energies (Figure 4(C) See route E3).

[0229] Organic compound 142_1 and organic compound 142_2 are such that one receives a hole and the other receives an electron. Alternatively, when one of the two is excited, it quickly forms an exciplex. Therefore, the exciplex in the light-emitting layer 140 Most of the excited molecules exist as exciplexes. The excited energy levels of the exciplexes (S PE Also is T PE ) is a host material (organic compound 142_1 and organic compound 142_2) that forms an exciplex. 42_2) S1 level (S PH1 and S PH2 ) and therefore has a lower excitation energy. This allows the host material 142 to form an excited state with the electrons. The driving voltage of the element can be reduced.

[0230] And the S of the exciplex PE and T PE The energy of both of the guest materials 141 (phosphorescent material The electrons are then transferred to the T1 level of the corresponding doped electrons (see routes E4 and E5 in Figure 4(C)).

[0231] In addition, the T1 level of the exciplex (T PE ) is the T1 level (T PG )twist By doing so, the singlet excitation energy and and triplet excitation energy in the S1 level (S PE ) and T1 level (T PE )mosquito The T1 level (T PG ) energy can be transferred to

[0232] In order to efficiently transfer excitation energy from the exciplex to the guest material 141, , the T1 level of the exciplex (T PE) are each organic compound that forms an exciplex (organic compound 14 2_1 and organic compound 142_2) T1 level (T PH1 and T PH2 ) or As a result, each of the organic compounds (organic compound 142_1 and organic Compound 142_2) is less likely to quench the triplet excitation energy of the exciplex. As a result, energy transfer occurs efficiently from the exciplex to the guest material 141.

[0233] In addition, the organic compound 142_1 and the organic compound 142_2 efficiently form an exciplex. In order to achieve this, the HOMO level of one of the organic compounds 142_1 and 142_2 must be The HOMO level of one is higher than the LUMO level of the other, and the LUMO level of the other is higher than the LUMO level of the other. For example, the organic compound 142_1 has a hole transporting property, and the organic compound 142_2 has a hole transporting property. When the organic compound 142_1 has electron transport properties, the HOMO level of the organic compound 142_2 It is preferable that the LUMO level of the organic compound 142_1 is higher than the HOMO level of the organic compound 142_2. It is preferable that the LUMO level of the organic compound 142_2 is higher than that of the organic compound 142_3. When organic compound 142 has a hole transporting property and organic compound 142_1 has an electron transporting property, organic compound 1 It is preferable that the HOMO level of 42_2 is higher than the HOMO level of the organic compound 142_1. , the LUMO level of organic compound 142_2 is higher than the LUMO level of organic compound 142_1. Specifically, it is preferable that the HOMO level of the organic compound 142_1 and the HOMO level of the organic compound 142 The energy difference between the HOMO level of _2 is preferably 0.05 eV or more, and more preferably The electron transport potential is preferably 0.1 eV or more, and more preferably 0.2 eV or more. The energy difference between the LUMO level of organic compound 142_1 and the LUMO level of organic compound 142_2 is , preferably 0.05 eV or more, more preferably 0.1 eV or more, and even more preferably It is preferably 0.2 eV or more.

[0234] In addition, the combination of organic compound 142_1 and organic compound 142_2 has hole transport properties. In the case of a combination of a compound having a property of electron transport and a compound having a property of electron transport, the mixing ratio Specifically, the carrier balance can be easily controlled by using a hole transporting material. The weight ratio of the compound having an electron transporting property to the compound having an electron transporting property is preferably in the range of 1:9 to 9:1. In addition, by having this configuration, the carrier balance can be easily controlled. In addition, the carrier recombination region can be easily controlled.

[0235] By configuring the light-emitting layer 140 as described above, the guest material 141 (phosphorescent material ) can be efficiently obtained.

[0236] In addition, the process of the above-mentioned route E3 to E5 is referred to as ExTET (Ex It is sometimes called plex-triplet energy transfer. In other words, the light-emitting layer 140 is configured to transmit the excitation energy from the exciplex to the guest material 141. In this case, the T PE From S PE High efficiency of reverse intersystem crossing is required Instead, S PE Since the quantum yield of light emitted from the It becomes possible.

[0237] In addition, the emission from the light-emitting layer 170 has an emission peak on the shorter wavelength side than the emission from the light-emitting layer 140. It is preferable that the light-emitting element has a phosphorescent material that emits light of a short wavelength. Therefore, by using fluorescent light for short wavelengths, It is possible to provide a light emitting element with little deterioration in luminance.

[0238] <Examples of materials that can be used for the light-emitting layer> Next, materials that can be used for the light-emitting layers 120, 140, and 170 will be described. The following explains each of these.

[0239] <Materials that can be used for the light-emitting layer 120> In the light-emitting layer 120, the host material 122 is present in the largest amount by weight, and the guest material 121 is The fluorescent material is dispersed in the host material 122. The S1 level of the host material 122 is The S1 level of the host material 121 (fluorescent material) is higher than the T1 level of the host material 122. It is preferable that the T1 level is lower than the T1 level of the photoresist material 121 (fluorescent material).

[0240] In the light-emitting layer 120, the guest material 121 is not particularly limited, but may be anthracene. Derivatives, tetracene derivatives, chrysene derivatives, phenanthrene derivatives, pyrene derivatives, Rylene derivatives, stilbene derivatives, acridone derivatives, coumarin derivatives, phenoxazine Derivatives, phenothiazine derivatives, etc. are preferred, and the fluorescent compound shown in the first embodiment is preferred. It can be used appropriately.

[0241] In addition, materials that can be used as the host material 122 in the light-emitting layer 120 include: Although there is no particular limitation, for example, tris(8-quinolinolato)aluminum(III) (abbreviation : Alq), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq3), bis(10-hydroxybenzo[h]quinolinato)beryllium(II)( Abbreviation: BeBq2), Bis(2-methyl-8-quinolinolato)(4-phenylphenolato) ) Aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II)( Abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phenolato]zinc(II)( abbreviation: ZnBTZ), and other metal complexes, such as 2-(4-biphenylyl)-5-(4-tert- butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5 -(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene Zene (abbreviation: OXD-7), 3-(4-biphenylyl)-4-phenyl-5-(4-tetraphenyl) 2,2',2' rt-Butylphenyl)-1,2,4-triazole (abbreviation: TAZ) '-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazo TPBI, bathophenanthroline (BPhen), bathocuproline BCP, 9-[4-(5-phenyl-1,3,4-oxadiazole-2- Heterocyclic compounds such as 4,4-phenyl-9H-carbazole (abbreviation: CO11), '-Bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB or is α-NPD), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1 ,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4'-bis[N-( Spiro-9,9'-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation Aromatic amine compounds such as bis(phenylene phosphate phosphate) and bis(phenylene phosphate phosphate). Nanthrene derivatives, pyrene derivatives, chrysene derivatives, dibenzo[g,p]chrysene derivatives Condensed polycyclic aromatic compounds such as 9,10-diphenylanthracene are specifically exemplified. (abbreviation: DPAnth), N,N-diphenyl-9-[4-(10-phenyl-9-anth tolyl)phenyl]-9H-carbazol-3-amine (abbreviation: CzA1PA), 4-( 10-phenyl-9-anthryl)triphenylamine (abbreviation: DPhPA), 4-(9 H-Carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenyl YGAPA, N,9-diphenyl-N-[4-(10-phenyl-9 -anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), ,9-diphenyl-N-{4-[4-(10-phenyl-9-anthryl)phenyl]furan N,9-diphenyl}-9H-carbazol-3-amine (abbreviation: PCAPBA), N-(9,10-diphenyl-2-anthryl)-9H-carbazol-3-amine (abbreviation: 2PCAPA), 6,12-dimethoxy-5,11-diphenylchrysene, N, N,N',N',N'',N'',N''',N'''-Octaphenyldibenzo[g, p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), 9-[4-(1 0-Phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: CzPA), 3,6-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H -Carbazole (abbreviation: DPCzPA), 9,10-bis(3,5-diphenylphenyl )anthracene (abbreviation: DPPA), 9,10-di(2-naphthyl)anthracene (abbreviation: :DNA), 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation :t-BuDNA), 9,9'-Bianthryl (abbreviation: BANT), 9,9'-(styryl Ben-3,3'-diyl)diphenanthrene (abbreviation: DPNS), 9,9'-(stilbe 3,3',3''-(phenyl-4,4'-diyl)diphenanthrene (abbreviation: DPNS2), Benzene-1,3,5-triyl)tripylene (abbreviation: TPB3) In addition, among these and known substances, the energy gap of the guest material 121 can be By selecting and using one or more materials with an energy gap larger than that of the good.

[0242] The light-emitting layer 120 may be composed of two or more layers. When the light-emitting layer 120 is formed by laminating the first light-emitting layer and the second light-emitting layer in this order from the hole transport layer side, A substance having a hole transporting property is used as a host material for the first light-emitting layer, and a substance having a hole transporting property is used as a host material for the second light-emitting layer. For example, a substance having an electron transport property is used as the insulating film.

[0243] In the light-emitting layer 120, the host material 122 is composed of a single compound. Alternatively, the light-emitting layer 120 may be made of a single compound or a plurality of compounds. The layer may contain materials other than the host material 122 and the guest material 121 .

[0244] <Materials that can be used for the light-emitting layer 140> In the light-emitting layer 140, the host material 142 is present in the largest amount by weight, and the guest material 141 The phosphorescent material is dispersed in the host material 142. The T1 level of the organic compound 142_1 and the organic compound 142_2 is the T A level higher than 1 is preferred.

[0245] Organic compounds 142_1 include zinc and aluminum metal complexes, as well as oxadiazo derivatives, triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzyl derivatives, Dibenzothiophene derivatives, dibenzofuran derivatives, pyrimidine derivatives, triazine derivatives, pyridine derivatives, bipyridine derivatives, phenanthroline derivatives Other examples include aromatic amines and carbazole derivatives. Specifically, the electron transporting material and the hole transporting material shown in Embodiment 1 are used. It is possible.

[0246] The organic compound 142_2 is a compound capable of forming an exciplex with the organic compound 142_1. Specifically, the electron transport material and the hole transport material shown in the first embodiment are preferably used in combination. In this case, the organic compound 142_1 and the organic compound 142_2 can be used. The emission peak of the exciplex formed is the triplet MLCT ( Metal to Ligand Charge Transfer (MTC) transition absorption band Specifically, organic compound 142_1 and organic compound 142_2 are selected so that they overlap with the absorption band on the longest wavelength side. It is preferable to select the object 142_2 and the guest material 141 (phosphorescent material). As a result, a light-emitting element with dramatically improved luminous efficiency can be obtained. In addition, when a thermally activated delayed fluorescent material is used, the absorption band on the longest wavelength side is the singlet absorption band. It is preferable that the thickness is 100 μm.

[0247] The guest material 141 (phosphorescent material) is an iridium, rhodium, or platinum-based organic Metal complexes, particularly organic iridium complexes, such as iridium The ortho-metal complex is preferably a 4H-triazole. Ligand, 1H-triazole ligand, imidazole ligand, pyridine ligand, pyrimidine Ligands include pyrazine ligands, isoquinoline ligands, and the like. Examples of the platinum complex include a platinum complex having a porphyrin ligand. The materials exemplified as the guest material 132 shown in 1 can be used.

[0248] The light-emitting material contained in the light-emitting layer 140 is a material capable of converting triplet excitation energy into light emission. As a material capable of converting the triplet excitation energy into light emission, a phosphorescent material is In addition to the above, thermally activated delayed fluorescent materials are also included. In other words, it may be interpreted as a thermally activated delayed fluorescent material.

[0249] In addition, materials that exhibit thermally activated delayed fluorescence can be independently converted from a triplet excited state to a single excited state by reverse intersystem crossing. The material may be capable of generating a doublet excited state, or may be an exciplex (or The material may be made of multiple materials that form a single layer (also called an exciplex).

[0250] When the thermally activated delayed fluorescent material is composed of one kind of material, specifically, The thermally activated delayed fluorescent material shown in 1 can be used.

[0251] In addition, when a thermally activated delayed fluorescent material is used as a host material, two types of exciplexes are formed. It is preferable to use a combination of the above-mentioned compounds. The combination of compounds that accept electrons and compounds that accept holes is called It is particularly preferred to use

[0252] <Materials that can be used for the light-emitting layer 170> The material that can be used for the light-emitting layer 170 is the same as that used for the light-emitting layer shown in the embodiment 1. By using a material that can achieve this, a light-emitting device with high luminous efficiency can be fabricated. It is possible.

[0253] In addition, the emission colors of the light-emitting materials contained in the light-emitting layers 120, 140, and 170 are There is no limitation, and each may be the same or different. The light emitted from each is mixed. For example, if the two emission colors are complementary to each other, The light-emitting layer 120 can emit white light. The emission peak wavelength of the luminescent material contained in the luminescent layer 170 is shorter than that of the luminescent material contained in the luminescent layer 170. is preferred.

[0254] The light-emitting unit 106, the light-emitting unit 108, the light-emitting unit 110, and the charge generating The layer 115 can be formed by deposition (including vacuum deposition), inkjet printing, coating, gravure printing, etc. The method can be formed as follows.

[0255] The configuration described in this embodiment mode may be used in appropriate combination with the configurations described in other embodiments. There can be.

[0256] (Embodiment 3) FIG. 5(A) is a top view showing a light-emitting device, and FIG. 5(B) is a cross-sectional view of FIG. 5(A) along lines AB and CD. This light emitting device is a cross-sectional view of a light emitting element. The illustrated driving circuit section (source side driving circuit) 601, pixel section 602, and driving circuit section (gate side The driver circuit 603 is a sealing substrate 604, a desiccant 625, and a shielding material 605. The inside surrounded by the sealing material 605 is a space 607 .

[0257] The lead wiring 608 is connected to the source side driver circuit 601 and the gate side driver circuit 603. The wiring is for transmitting the signals to be input, and the FPC (flexible printed circuit board) is the external input terminal. Video signal, clock signal, start signal, reset signal, etc. from the 609 Although only the FPC is shown here, the FPC has a printed wiring board. Even if a printed wiring board (PWB) is installed, The light emitting device in this specification includes not only the light emitting device itself but also an FPC or This includes the state where the PWB is installed.

[0258] Next, a cross-sectional structure of the light emitting device will be described with reference to FIG. A driving circuit section and a pixel section are formed on the source side driving circuit section. A circuit 601 and one pixel in a pixel portion 602 are shown.

[0259] The source side driver circuit 601 includes an n-channel TFT 623 and a p-channel TFT 624. The driver circuit is a combination of various CMOS circuits, It may be formed of a MOS circuit or an NMOS circuit. This shows a driver integrated type with a driver circuit formed on the board, but this is not necessarily required. Alternatively, it may be formed externally.

[0260] The pixel section 602 includes a switching TFT 611, a current control TFT 612 and its drain. The pixel includes a first electrode 613 electrically connected to the input. An insulator 614 is formed so as to cover the end of the electrode 613. The insulating layer can be formed by using a photosensitive resin film having a mold.

[0261] In order to improve the coverage of the film formed on the insulator 614, the insulator 614 is The upper end or the lower end is formed to have a curved surface. For example, When photosensitive acrylic is used as the material, it is possible to make only the upper end of the insulator 614 curved. The radius of curvature of the curved surface is preferably 0.2 μm or more and 0.3 μm or less. Either a negative photosensitive material or a positive photosensitive material may be used as the substrate 614. can be done.

[0262] An EL layer 616 and a second electrode 617 are formed on the first electrode 613. Here, the material used for the first electrode 613 functioning as an anode is a material having a work function of It is desirable to use a material with a large capacitance. For example, an ITO film or an indium tin oxide film containing silicon. Indium tin oxide film, indium oxide film containing 2wt% to 20wt% zinc oxide, nitride In addition to single-layer films such as titanium film, chromium film, tungsten film, Zn film, and Pt film, titanium nitride film and a film mainly composed of aluminum; A three-layer structure of a titanium nitride film and a titanium oxide film can be used. It has low resistance as an anode, provides good ohmic contact, and also functions as an anode. It is possible.

[0263] The EL layer 616 is formed by deposition using a deposition mask, inkjet printing, or spin coating. The EL layer 616 can be formed by various methods such as the above. The polymer may be a polymer compound (including an oligomer or a dendrimer).

[0264] Furthermore, a material for a second electrode 617 formed on the EL layer 616 and functioning as a cathode As the material, materials with a small work function (Al, Mg, Li, Ca, or alloys or compounds of these) It is preferable to use a material such as MgAg, MgIn, or AlLi. When the generated light is transmitted through the second electrode 617, the second electrode 617 is made thin. A thin metal film and a transparent conductive film (ITO, an oxide film containing 2 wt% to 20 wt% zinc oxide) Indium tin oxide, silicon-containing indium tin oxide, zinc oxide (ZnO, etc.) It is better to use.

[0265] The first electrode 613, the EL layer 616, and the second electrode 617 form a light-emitting element 618. The light emitting element 618 is a light emitting element having the configurations of the first and second embodiments. It is preferable that the pixel portion is formed with a plurality of light emitting elements. In the light emitting device of the embodiment, a light emitting device having the configuration described in the first and second embodiments is The light-emitting element may include both a light-emitting element and a light-emitting element having other configurations.

[0266] Furthermore, the sealing substrate 604 is bonded to the element substrate 610 with a sealant 605, A light emitting element is disposed in a space 607 surrounded by a child substrate 610, a sealing substrate 604, and a sealant 605. 618. The space 607 is filled with a filler. In addition to inert gas (nitrogen, argon, etc.) being filled, resin, desiccant or its Sometimes it is filled with both.

[0267] It is preferable to use epoxy resin or glass frit for the sealing material 605. It is desirable that these materials are as impermeable to moisture and oxygen as possible. Materials used for the sealing substrate 604 include glass substrates, quartz substrates, and FRP (Fiber Reinforced Plastics). reinforced plastics), PVF (polyvinyl fluoride), polyester A plastic substrate made of, for example, polyester or acrylic can be used.

[0268] As described above, a light emitting device using the light emitting elements described in the first and second embodiments can be obtained.

[0269] <Light-emitting device configuration example 1> FIG. 6 shows an example of a light-emitting device in which a light-emitting element that emits white light is formed and a color layer (color filter) is formed. An example of a light emitting device in which a GaN-GaN filter is formed is shown.

[0270] FIG. 6A shows a substrate 1001, an insulating base film 1002, a gate insulating film 1003, and a gate electrode. 1006, 1007, 1008, a first interlayer insulating film 1020, a second interlayer insulating film 1021 , a peripheral portion 1042, a pixel portion 1040, a driving circuit portion 1041, and a first electrode 102 of a light-emitting element. 4W, 1024R, 1024G, 1024B, partition wall 1026, EL layer 1028, light-emitting element 10, a second electrode 1029, a sealing substrate 1031, a sealant 1032, and the like are shown.

[0271] In addition, in FIG. 6(A) and FIG. 6(B), colored layers (red colored layer 1034R, green colored layer 10 34G, and a blue colored layer 1034B) are provided on a transparent substrate 1033. A black matrix 1035 may be further provided. The transparent base material 1033 is aligned and fixed to the substrate 1001. The color layers are covered with an overcoat layer 1036. In FIG. The light-emitting layer emits light to the outside without passing through the colored layers, and the light-emitting layer emits light to the outside by passing through the colored layers of each color. The light that does not pass through the colored layer is white, and the light that passes through the colored layer is red, blue, or green. This allows images to be displayed using four color pixels.

[0272] In FIG. 6B, a red colored layer 1034R, a green colored layer 1034G, and a blue colored layer 103 An example in which 4B is formed between the gate insulating film 1003 and the first interlayer insulating film 1020 is shown. As shown in FIG. 6B, the colored layer may be provided between the substrate 1001 and the sealing substrate 1031. stomach.

[0273] In the light emitting device described above, the light is taken in toward the substrate 1001 on which the TFT is formed. The light emitting device has a bottom emission structure, but the light is taken in from the sealing substrate 1031 side. The light emitting device may have a top emission structure.

[0274] <Configuration Example 2 of Light Emitting Device> A cross-sectional view of a top-emission type light-emitting device is shown in FIG. A connection electrode that connects the TFT and the anode of the light-emitting element can be formed. The process is the same as that of the bottom emission type light emitting device until the third interlayer is formed. An insulating film 1037 is formed to cover the electrode 1022. This insulating film serves to flatten the surface. The third interlayer insulating film 1037 may be made of the same material as the second interlayer insulating film 1021 or other materials. The substrate can be formed using a variety of materials.

[0275] Here, the first lower electrodes 1025W, 1025R, 1025G, and 1025B of the light-emitting element are The anode is assumed to be the anode, but it can also be the cathode. In the case of an optical device, the lower electrodes 1025W, 1025R, 1025G, and 1025B are reflective electrodes. The second electrode 1029 has a function of reflecting light and a function of transmitting light. In addition, the second electrode 1029 and the lower electrode 1025W, 102 A microcavity structure is applied between 5R, 1025G, and 1025B to filter light of a specific wavelength. The EL layer 1028 has the same structure as that described in the second embodiment. The device has such a configuration that white light can be emitted.

[0276] In FIG. 6(A), FIG. 6(B), and FIG. 7, the EL layer configuration for obtaining white light emission is as follows: This can be achieved by using multiple light-emitting layers or multiple light-emitting units. However, the configuration for obtaining white light emission is not limited to these.

[0277] In the top emission structure shown in Figure 7, the colored layers (red colored layer 1034R, green colored layer The sealing can be performed by using a sealing substrate 1031 provided with a blue colored layer 1034G and a blue colored layer 1034B. The sealing substrate 1031 has a black layer (black matrix) between the pixels. A coloring layer (a red coloring layer 1034R, a green coloring layer 1035) may be provided. 034G, blue colored layer 1034B) and black layer (black matrix) are overcoated The sealing substrate 1031 may be covered with a transparent layer. .

[0278] In addition, although an example of full-color display using four colors, red, green, blue, and white, is shown here, the present invention is not limited to this. Alternatively, full color display may be performed using three colors, red, green, and blue. Alternatively, full color display may be performed using four colors, red, green, blue, and yellow. A full color display may be performed.

[0279] As described above, a light emitting device using the light emitting elements described in the first and second embodiments can be obtained.

[0280] Note that this embodiment mode can be appropriately combined with other embodiment modes.

[0281] (Embodiment 4) In this embodiment, an electronic device according to one embodiment of the present invention will be described.

[0282] One embodiment of the present invention is a light-emitting element using an organic electroluminescence (EL), which has a flat surface and has good luminous efficiency. In addition, according to one embodiment of the present invention, a light-emitting device having a curved surface can be manufactured. In addition, according to one embodiment of the present invention, a flexible electronic device can be manufactured. Thus, it is possible to manufacture highly reliable electronic devices having excellent light-emitting efficiency.

[0283] Examples of electronic devices include television sets, desktop or notebook PCs, etc. Computers, monitors for computers, digital cameras, digital video cameras Cameras, digital photo frames, mobile phones, portable game consoles, personal digital assistants, audio playback Examples of such devices include large gaming machines such as pachinko machines.

[0284] In addition, the light-emitting device of one embodiment of the present invention can achieve high visibility regardless of the intensity of external light. Therefore, portable electronic devices, wearable electronic devices, and It can be suitably used for child book terminals and the like.

[0285] A portable information terminal 900 shown in FIGS. 8A and 8B includes a housing 901, a housing 902, a display unit 90 3, and a hinge portion 905.

[0286] The housing 901 and the housing 902 are connected by a hinge portion 905. The mobile information terminal 900 includes: It can be unfolded from the folded state (FIG. 8(A)) to the state shown in FIG. 8(B). This makes it highly portable when you carry it around, and when you use it, the large display area makes it easy to see. Excellent recognition.

[0287] The portable information terminal 900 has a housing 901 and a housing 902 connected by a hinge portion 905. A flexible display unit 903 is provided.

[0288] A light-emitting device manufactured according to one embodiment of the present invention can be used for the display portion 903. This makes it possible to manufacture portable information terminals with a high yield.

[0289] The display unit 903 is capable of displaying at least one of document information, still images, and moving images. When document information is displayed on the display unit, the portable information terminal 900 is used as an electronic book terminal. It can be used as such.

[0290] When the portable information terminal 900 is unfolded, the display portion 903 is held in a largely curved state. For example, the radius of curvature is 1 mm or more and 50 mm or less, preferably 5 mm or more and 30 mm or less. The display unit 903 is supported by the housing 901 and the cover 902. Pixels are continuously arranged from 902 to 902, enabling a curved display.

[0291] The display unit 903 functions as a touch panel and can be operated by a finger, a stylus, etc. can.

[0292] It is preferable that the display unit 903 is composed of one flexible display. This makes it possible to perform continuous display without interruption between the housing 901 and the housing 902. In addition, a display may be provided in each of the housings 901 and 902. You may do so.

[0293] The hinge portion 905 is a portion that connects the housing 901 and the housing 902 when the mobile information terminal 900 is unfolded. It is preferable to have a locking mechanism to prevent the angle from becoming larger than a predetermined angle. For example, the angle at which the door will lock (will not open any further) must be greater than 90 degrees and less than 180 degrees. Typically, the angle is 90 degrees, 120 degrees, 135 degrees, 150 degrees, or 17 degrees. 5 degrees, etc. This improves the convenience, safety, and Reliability can be improved.

[0294] If the hinge portion 905 has a locking mechanism, the display portion 903 can be opened without applying excessive force. Therefore, it is possible to prevent the display unit 903 from being damaged. It can be achieved.

[0295] The housing 901 and the housing 902 are provided with a power button, an operation button, an external connection port, a speaker, a microphone, and the like. It may have an indentation or the like.

[0296] A wireless communication module is provided in either the housing 901 or the housing 902. Internet, LAN (Local Area Network), Wi-Fi (registered trademark ) and the like.

[0297] A portable information terminal 910 shown in FIG. 8C includes a housing 911, a display unit 912, and an operation button 913. , an external connection port 914, a speaker 915, a microphone 916, a camera 917, etc.

[0298] A light-emitting device manufactured according to one embodiment of the present invention can be used for the display portion 912. This makes it possible to manufacture portable information terminals with a high yield.

[0299] The mobile information terminal 910 has a touch sensor on the display unit 912. All operations, such as inputting characters, can be performed by touching the display 912 with a finger or a stylus. It can be done.

[0300] In addition, the operation button 913 is operated to turn the power on and off, and to display on the display unit 912. For example, you can change the type of image displayed on the main screen from the email composition screen. You can switch to the menu screen.

[0301] In addition, a detection device such as a gyro sensor or an acceleration sensor is provided inside the portable information terminal 910. By providing the above, the orientation of the mobile information terminal 910 (vertical or horizontal) can be determined and the screen of the display unit 912 can be adjusted. The display orientation can be switched automatically. The screen orientation can also be switched by The input is made by touching the display unit 912, by operating the operation button 913, or by inputting voice using the microphone 916. It can also be performed by using force or the like.

[0302] The mobile information terminal 910 is, for example, one or more devices selected from a telephone, a notebook, an information viewing device, etc. Or it has multiple functions. Specifically, it can be used as a smartphone. The information terminal 910 is, for example, a mobile phone, an e-mail, a document viewing and creation, a music playback, a video It can run various applications such as playback, internet communication, and games. do.

[0303] The camera 920 shown in FIG. 8D includes a housing 921, a display unit 922, an operation button 923, and a shutter. The camera 920 also has a detachable lens 926. It is attached.

[0304] The light-emitting device manufactured according to one embodiment of the present invention can be used for the display portion 922. This allows the camera to be manufactured with a high yield.

[0305] Here, the camera 920 and the lens 926 can be removed from the housing 921 and replaced. However, the lens 926 and the housing 921 may be integrated together.

[0306] The camera 920 captures still or moving images by pressing the shutter button 924. In addition, the display unit 922 has a function as a touch panel. It is also possible to capture an image by touching the

[0307] The camera 920 can be equipped with a strobe device, viewfinder, etc. Alternatively, these may be incorporated into the housing 921.

[0308] 9A to 9E are diagrams showing electronic devices. These electronic devices are housed in a housing 9000. , a display unit 9001, a speaker 9003, and operation keys 9005 (power switches or operation switches switch), connection terminal 9006, sensor 9007 (force, displacement, position, speed, acceleration, angle Speed, rotation speed, distance, light, liquid, magnetism, temperature, chemicals, sound, time, hardness, electric field, current, Includes the ability to measure voltage, power, radiation, flow, humidity, gradient, vibration, odor or infrared. The device is equipped with a microphone 9008, etc.

[0309] A light-emitting device manufactured according to one embodiment of the present invention can be suitably used for the display portion 9001. This allows electronic devices to be manufactured with high yields.

[0310] The electronic devices shown in FIGS. 9A to 9E can have various functions. Functions for displaying various information (still images, videos, text images, etc.) on the display unit, touch panel function Functions such as displaying calendars, dates, or times, and various software (programs) ) to control processing, wireless communication function, and wireless communication function to connect various computers The function to connect to a data network, and the function to transmit or receive various data using wireless communication functions. The function to be performed, read out the program or data recorded on the recording medium and display it on the display unit The electronic devices shown in FIGS. 9(A) to 9(E) can have the following functions. The functions are not limited to these, and other functions may be included.

[0311] FIG. 9A shows a wristwatch-type portable information terminal 9200, and FIG. 9B shows a wristwatch-type portable information terminal 9201 are perspective views showing the same.

[0312] The mobile information terminal 9200 shown in FIG. 9A is capable of performing a variety of functions, including mobile phone, e-mail, document viewing and creation, It can be used for various applications such as music playback, internet communication, and computer games. In addition, the display surface of the display unit 9001 is curved, and the curved The portable information terminal 9200 can display information on the display surface. For example, it is possible to use a wireless headset to perform short-distance wireless communication. By communicating with each other, you can talk hands-free. 200 has a connection terminal 9006 and can directly exchange data with other information terminals via a connector. It is also possible to charge the battery via the connection terminal 9006. The charging operation may be performed by wireless power supply without going through the connection terminal 9006.

[0313] The portable information terminal 9201 shown in FIG. 9B is different from the portable information terminal shown in FIG. The display surface of the display unit 9001 is not curved. It has a non-rectangular shape (a circular shape in FIG. 9(B)).

[0314] 9C to 9E are perspective views showing a foldable portable information terminal 9202. FIG. 9C is a perspective view of the portable information terminal 9202 in an unfolded state, and FIG. The portable information terminal 9202 is in the process of changing from one of the unfolded state and the folded state to the other. 9(E) is a perspective view of the portable information terminal 9202 in a folded state. be.

[0315] The portable information terminal 9202 is highly portable when folded, and has a seam when unfolded. The display area of ​​the portable information terminal 9202 is large and has excellent visibility. 9001 is supported by three housings 9000 connected by hinges 9055 . The two housings 9000 are bent via the hinge 9055, so that the portable information terminal 9 202 can be reversibly transformed from an unfolded state to a folded state. For example, The portable information terminal 9202 can be bent with a radius of curvature of 1 mm or more and 150 mm or less.

[0316] This embodiment mode can be combined with other embodiment modes as appropriate.

[0317] (Embodiment 5) In this embodiment, an example in which the light-emitting element of one embodiment of the present invention is applied to various lighting devices will be described. 10 and 11. By using a light-emitting element which is one embodiment of the present invention, Thus, a highly reliable lighting device with good luminous efficiency can be manufactured.

[0318] The light-emitting element of one embodiment of the present invention can be fabricated over a flexible substrate to have a curved surface. It is possible to realize electronic devices and lighting devices having a light-emitting region.

[0319] In addition, a light-emitting device using a light-emitting element according to one embodiment of the present invention can be used for automobile lighting. For example, lighting can be installed on the windshield, ceiling, etc.

[0320] FIG. 10(A) shows a perspective view of one side of a multifunction terminal 3500, and FIG. 3 shows a perspective view of the other side of the multi-function terminal 3500. 2 incorporates a display unit 3504, a camera 3506, and lighting 3508. The light emitting device of the embodiment can be used for lighting 3508.

[0321] The light emitting device according to one embodiment of the present invention is used for the light source 3508, and the light source 3508 functions as a surface light source. Therefore, point light sources such as LEDs (Light Emitting Diodes) Unlike the above, light with less directivity can be obtained. For example, When used in combination, the light 3508 is turned on or blinks, and the camera 3506 The lighting 3508 has a function as a surface light source, so it can capture images of natural You can take photos that look like they were taken under light.

[0322] The multifunction terminal 3500 shown in FIGS. 10(A) and 10(B) is the same as the multifunction terminal 3500 shown in FIGS. As with the electronic device shown in FIG.

[0323] In addition, inside the housing 3502, a speaker, a sensor (force, displacement, position, speed, acceleration, angle Speed, rotation speed, distance, light, liquid, magnetism, temperature, chemicals, sound, time, hardness, electric field, current, Includes functions to measure voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays The multifunction terminal 3500 may have a built-in speaker, a microphone, etc. By providing a detection device having a sensor that detects the inclination, such as a gyro or acceleration sensor, The screen display of the display unit 3504 is automatically adjusted by determining the orientation (portrait or landscape) of the functional terminal 3500. It is possible to make it switchable.

[0324] The display unit 3504 can also function as an image sensor. By touching the palm or fingers to the sensor 504 and capturing an image of the palm print, fingerprint, or the like, personal authentication can be performed. In addition, the display unit 3504 may be provided with a backlight that emits near-infrared light or a sensor that emits near-infrared light. If a light source for imaging is used, finger veins, palm veins, etc. can also be imaged. The light-emitting device according to one embodiment of the present invention may be applied to the above-mentioned embodiment 04.

[0325] FIG. 10C shows a perspective view of a security light 3600. The light 3600 is The housing 3602 has a light 3608 on the outside, and the housing 3602 is equipped with a speaker 3610 and the like. The light-emitting element of one embodiment of the present invention can be used for the lighting 3608.

[0326] Light 3600 may, for example, be a device that grasps, holds, or holds light 3608. The inside of the housing 3602 is provided with a light 3600. The light emitting device may be provided with an electronic circuit that can control the light emitting method. Alternatively, the circuit may be such that light can be emitted intermittently multiple times, or the light emission current value may be controlled. The circuit may be configured so that the amount of light emitted can be adjusted by adjusting the amount of light emitted from the light source 3608. At the same time, a circuit may be incorporated to output a loud alarm sound from the speaker 3610. stomach.

[0327] The Light 3600 can emit light in any direction, so it can be used to target, for example, thugs. The Light 3600 can also be equipped with a digital sensor to scare off predators. The device may be provided with a camera such as a still camera, thereby providing a function for photographing images.

[0328] FIG. 11 shows an example in which the light-emitting element is used as an indoor lighting device 8501. Since the surface area can be increased, a large-area lighting device can be formed. By using a housing having such a curved light-emitting area, a lighting device 8502 can be formed. The light-emitting element shown in this embodiment mode has a thin film shape, and the design of the housing has a high degree of freedom. Therefore, it is possible to form lighting devices with various elaborate designs. A large lighting device 8503 may be provided on the wall. A touch sensor may be provided in 503 to turn the power on or off.

[0329] In addition, by using light-emitting elements on the surface of the table, it has the function of a table. The lighting device 8504 can be used as a lighting device. This makes it possible to provide a lighting device that also functions as furniture.

[0330] In this manner, a lighting device and an electronic device can be obtained by using the light-emitting device of one embodiment of the present invention. Note that the lighting devices and electronic devices to which the present invention can be applied are the same as those described in this embodiment. The present invention can be applied to electronic devices in a wide range of fields.

[0331] The structure described in this embodiment may be used in appropriate combination with structures described in other embodiments. There can be. EXAMPLES

[0332] Example 1 In this example, a manufacturing example of a light-emitting element, which is one type of electronic device according to one embodiment of the present invention, and The characteristics of the light-emitting element will be described. In addition, the refractive index and The refractive index of the hole injection layer will be described. A cross-sectional view of the device structure produced in this example is shown in FIG. The details of the device structure are shown in Table 1. The structures and abbreviations of the compounds used are listed below. Shown below.

[0333] [ka]

[0334] [Table 1]

[0335] [Table 2]

[0336] [Table 3]

[0337] <Refractive index measurement> Comparative light-emitting element 1 to comparative light-emitting element 4, light-emitting element 5 to light-emitting element 8, and light-emitting element 9 to The organic compound used in the hole injection layer 111 of the element 12 and the refractive index of the hole injection layer 111 were measured. The refractive index was measured using a rotating compensator type multi-angle high-speed spectroscopic ellipsometer ( The measurement was performed at room temperature using a quartz substrate. The normal and extraordinary values ​​were measured, and The verage was calculated.

[0338] The results of measuring the refractive index of each film using light with a wavelength of 532 nm are shown in Figure 12. DBT3P-II used in the light-emitting element 1 to the comparative light-emitting element 4 has the highest refractive index. It was found that the dmCBP used in the light-emitting elements 5 to 8 was n Ordinary It was found that the organic compound has a low refractive index of 1.75 or less. The TAPC used in the light-emitting device 12 has an n Ordinary of 1.70 or less. It was found to be an organic compound with a low refractive index.

[0339] In addition, the hole injection layer 111 is required to have a hole injection property, and therefore, it is preferable that the layer contains an electron donating material. It is preferable that the hole injection layer of each light-emitting element uses MoO3 having a high refractive index as an electron donor material. 111 is expected to have a high refractive index. However, as shown in FIG. The refractive index of the film in which MoO3, which is 11, is added to each organic compound is It was found that the refractive index of the hole injection layer 111 was slightly higher than that of the material. By using an organic compound with a low refractive index, the electron donating material can be made to have a high refractive index. It was found that a hole injection layer 111 with a low refractive index could be obtained by using

[0340] In addition, as shown in FIG. 12, the hole injection layer 111 of each light emitting element has a thickness of n It was found that the difference between Ordinary and n Extraordinary was small. That is, the mixed film of the electron-accepting material MoO3 and organic compounds has different properties compared to the organic compound film. It was found that the directional property decreased.

[0341] <Fabrication of light-emitting element> <Fabrication of Comparative Light-Emitting Element 1 to Comparative Light-Emitting Element 4> 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). The refractive index (n Ordinary) of the film for light with a wavelength of 532 nm is 2.07.

[0342] Next, 1,3,5-tri-(4-dibenzothiophene) was deposited on the electrode 101 as a hole injection layer 111. DBT3P-II) and MoO3 were mixed in a weight ratio of (DBT The ratio of 3P-II:MoO3 was 2:0.5 and the thickness was x1 nm. The value of x1 differs for each light-emitting element. The values ​​are shown in Table 2.

[0343] Next, a hole transport layer 112 was formed on the hole injection layer 111 by depositing PCCP to a thickness of 20 nm. The deposition was carried out so that

[0344] Next, on the hole transport layer 112, a light emitting layer 130(1) was formed by CCP and Ir(pbi-diBuCNp)3 (a mixture of fac isomer and mer isomer = 3:2) The weight ratio (4,6mCzP2Pm:PCCP:Ir(pbi-diBuCNp)3) is 0. The mixture was evaporated in a ratio of 5:0.5:0.1 to a thickness of 20 nm, and then evaporatively deposited. The optical layer 130(2) is made of a material having a weight ratio of (4.6mCzP2Pm:PCCP:Ir(pbi-d The ratio of iBuCNp)3) is 0.8:0.2:0.1 and the thickness is 20 nm. In the light-emitting layer 130(1) and the light-emitting layer 130(2), Ir( pbi-diBuCNp)3 is the guest material that exhibits phosphorescence.

[0345] Next, a 4.6mCz P2Pm was co-deposited to a thickness of 20 nm. As a second electron transport layer 118(2), bathophenanthroline (abbreviation: BPhe n) was evaporated to a film thickness of 10 nm.

[0346] Next, a lithium fluoride ( LiF) was evaporated to a thickness of 1 nm.

[0347] 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.

[0348] Next, the device is sealed using an organic EL sealing material in a nitrogen atmosphere glove box. The glass substrate for the organic material was fixed to the glass substrate on which the organic material was formed, and the comparative light-emitting element 1 was formed. Specifically, the organic material on the glass substrate on which the organic material was formed was sealed. A sealing material is applied around the substrate, and the substrate and a glass substrate for sealing are attached to each other. 365 nm ultraviolet light at 6 J / cm 2 The film was irradiated with light and then heat-treated at 80°C for 1 hour. Thus, comparative light-emitting elements 1 to 4 were obtained.

[0349] <Fabrication of Light-Emitting Elements 5 to 8> The manufacturing process of the light-emitting elements 5 to 8 is the same as the manufacturing process of the comparative light-emitting elements 1 to 4. The only difference is the manufacturing process of the hole injection layer 111. The other processes are the same as those of the comparative light-emitting element 1 to the comparative light-emitting element 2. The same procedure was followed for child 4.

[0350] On the electrode 101, a hole injection layer 111(1) was formed by dissolving dmCBP and MoO3 in a weight ratio of ( The ratio of dmCBP:MoO3 was 2:0.5 and the thickness was 35 nm. Then, DBT3P-II and MoO3 were mixed in a weight ratio of (DBT3P-II:MoO 3) were co-deposited in a ratio of 2:0.5 to a thickness of x2 nm. The value of x2 varies depending on the light-emitting element, and the value of x2 for each light-emitting element is shown in Table 3. .

[0351] <Fabrication of Light-Emitting Elements 9 to 12> The fabrication process of the light-emitting elements 9 to 12 was the same as that of the comparative light-emitting elements 1 to 4. The only difference between the process and the process for forming the hole injection layer 111 is the same as that of the comparative light-emitting element 1 to the comparative light-emitting element 2. The same procedure was carried out as for element 4.

[0352] A hole injection layer 111(1) was formed on the electrode 101 by mixing TAPC and MoO3 in a weight ratio of (T Co-evaporation was performed so that the ratio of APC:MoO3 was 2:0.5 and the thickness was 35 nm. Then, DBT3P-II and MoO3 were mixed in a weight ratio of (DBT3P-II:MoO3) The mixture was co-deposited so that the ratio was 2:0.5 and the thickness was x2 nm. The value differs for each light-emitting element, and the value of x2 for each light-emitting element is shown in Table 3.

[0353] <Characteristics of light-emitting element> Next, the comparative light-emitting elements 1 to 4 and the light-emitting elements 5 to 1 The characteristics of the 2 were measured. The luminance and CIE chromaticity were measured using a color luminance meter (Topcon, BM A multichannel spectrometer (Hamamatsu Photonics Co., Ltd.) was used to measure the electroluminescence spectrum. The measurements of each light-emitting element were performed in an atmosphere maintained at room temperature (23°C). The experiment was conducted in an atmospheric condition.

[0354] Among the light-emitting devices fabricated, the current efficiency-luminance of comparative light-emitting device 1, light-emitting device 5, and light-emitting device 9 was compared. The current density-voltage characteristics are shown in Fig. 13. The external quantum efficiency The brightness characteristics are shown in Figure 15. Note that the external quantum efficiency values ​​shown in Figure 15 are corrected for viewing angles. The external quantum efficiency is measured from the front direction of the light-emitting element, not from the hole injection direction. As the organic compound of the insulating layer 111, the comparative light-emitting element 1 contains DBT3P-II, and the light-emitting element 5 contains d The light-emitting element 9 is an element using mCBP and TAPC, respectively. All of the above sections have the same element structure.

[0355] As shown in FIG. 14, the comparative light-emitting element 1, the light-emitting element 5, and the light-emitting element 9 have equivalent current density-voltage characteristics. Therefore, it was found that the hole injection layer 111 was formed using an organic compound with a low refractive index. It was also found that the ZnO-based SiO2 ...

[0356] 13 and 15, the comparative light-emitting element 1, the light-emitting element 5, and the light-emitting element 9 have a luminance of 100 cd / It was found that the current efficiency exceeded 1 A and the external quantum efficiency exceeded 30%. In addition, organic compounds with low refractive index, dmCBP and TAPC, were used for the hole injection layer 111. The light-emitting elements 5 and 9 used for comparison were made of DBT3P-II, a material with a high refractive index. It showed higher efficiency than Photonic Device 1.

[0357] In addition, the comparative light-emitting element 1, the light-emitting element 5, and the light-emitting element 9 were each subjected to a current of 25 mA / cm 2 Current at current density of FIG. 16 shows the emission spectrum when the comparative light-emitting element 1 and the light-emitting element 2 were passed through the light-emitting element. The emission spectra of the optical element 5 and the light emitting element 9 have peaks around 515 nm and 550 nm. The guest material contained in the light-emitting layer 130 is Ir(pbi-diBuCNp). It was found that this was due to the emission of 3.

[0358] In addition, 1000 of the comparative light-emitting element 1 to the comparative light-emitting element 4 and the light-emitting element 5 to the light-emitting element 12 cd / m 2 The external quantum efficiency shown in Table 4 is corrected for the viewing angle. The external quantum efficiency after the above-mentioned measurement is shown.

[0359] [Table 4]

[0360] From the above results, the comparative light-emitting elements 1 to 4 and the light-emitting element 5 fabricated in this example The light-emitting element 12 exhibits good driving voltage and luminous efficiency regardless of the structure of the hole injection layer 111. It is clear that this is the case.

[0361] <Relationship between refractive index of hole injection layer 111 and external quantum efficiency> FIG. 17 shows the results of the organic material used in each hole injection layer 111 using the values ​​of each element shown in Table 4. The relationship between chromaticity x and external quantum efficiency is shown in Figure 17. The values ​​of the comparative light-emitting element 1 to the comparative light-emitting element 4 are shown in the curve data of "dmCBP". The values ​​for element 5 to element 8 are shown in the "TAPC" curve data, and the values ​​for element 9 to element 8 are shown in the "TAPC" curve data. The values ​​of Comparative Light-Emitting Element 1 to Comparative Light-Emitting Element 4 and Light-Emitting Element 5 were used. In the light-emitting elements 5 to 12, even if the thickness of the hole injection layer 111 is the same, Since the refractive index differs depending on the organic compound, the optical path length from the light-emitting region of each light-emitting element to the substrate is When the optical path length changes, the external quantum efficiency also changes, so the refraction of the hole injection layer 111 When evaluating the relationship between the efficiency and external quantum efficiency, it is necessary to adjust the optical path length for each light-emitting device. It is difficult to finely adjust the thickness of the EL layer during the fabrication of the light-emitting device.

[0362] In light-emitting devices using the same light-emitting material, the optical path length from the light-emitting region of each light-emitting device to the substrate is If they are different, the emission spectrum and chromaticity obtained from the light-emitting element will also differ. When the same chromaticity is obtained from each light-emitting element, the emission spectrum extracted from each light-emitting element is In other words, if the same chromaticity is obtained from each light-emitting element, Therefore, the optical path length from the light-emitting region of each light-emitting element to the substrate is the same. By considering the relationship between the efficiency and the chromaticity x or chromaticity y, the refractive index of the hole injection layer 111 and the external quantum Efficiency relationships can be evaluated.

[0363] As shown in FIG. 12, the organic compounds used in the hole injection layer 111 are DBT3P-II>dmCBP>TA 17, the refractive index of the organic compound used in the hole injection layer 111 is low, that of the organic compound is low, and that of the organic compound is high. This is because the external quantum efficiency is higher for the evanescent mode. This is because attenuation is reduced and light extraction efficiency is improved.

[0364] As described above, by using an organic compound with a low refractive index for the hole injection layer 111, the hole injection characteristics It was found that a light emitting device having good light extraction efficiency while maintaining the above properties could be obtained.

[0365] <Volume ratio of electron donor and electron acceptor in the hole injection layer 111 and external quantum efficiency Relationship > Here, the electron-accepting material (MoO3) for the electron-donating material in the hole injection layer 111 The relationship between the volume ratio of MoO3 (hereinafter referred to as the volume ratio of MoO3) and the external quantum efficiency was investigated. The details of the device structure are shown in Table 5. The structures and abbreviations of the compounds used are shown below. For other organic compounds, see the above-mentioned compounds.

[0366] [ka]

[0367] [Table 5]

[0368] [Table 6]

[0369] <Fabrication of Light-emitting Elements 13 to 18> The fabrication process of the light-emitting elements 13 to 18 is the same as that of the comparative light-emitting elements 1 to 4. The only differences were the manufacturing process of the hole injection layer 111 and the light-emitting layer 130, and the other processes were the same as those of the comparative light-emitting element. The same procedure was carried out for the light-emitting element 1 to the comparative light-emitting element 4.

[0370] On the electrode 101, a hole injection layer 111 was formed by mixing DBT3P-II and MoO3 in a weight ratio (D The ratio of BT3P-II:MoO3 was 3-y:y and the thickness was 40 nm. The value of y differs for each light-emitting element. The values ​​are shown in Table 6. Table 6 also shows the results of converting the weight ratio into the volume ratio of MoO3. show.

[0371] Next, on the hole transport layer 112, a light emitting layer 130(1) was formed by CCP and Ir(tBuppm)3 were mixed in a weight ratio of (4,6mCzP2Pm:PCCP:Ir(t Buppm)3) is 0.5:0.5:0.075 and the thickness is 20 nm. Then, as the light-emitting layer 130(2), a layer of PCCP:Ir(tBuppm)3) is 0.8:0.2:0.075, and The co-deposition was performed so that the thickness became 20 nm. In 2), Ir(tBuppm)3 is the guest material that exhibits phosphorescence.

[0372] <Characteristics of light-emitting element> Next, the luminance-external quantum efficiency characteristics of the light-emitting elements 13 to 18 fabricated above were measured. The measurements were carried out as described above.

[0373] Figure 18 shows the 10,000cd / m 2 External quantum efficiency near the hole injection layer 111 The relationship between the volume ratio of MoO3 and the electron donating ability is shown in Fig. 18. In the region greater than 0 and less than 0.3 for the material, the external quantum efficiency is high at 24% to 26%. The efficiency is shown in Fig. 1, but it can be seen that the efficiency decreases in the region larger than 0.3. In the region where the volume ratio of MoO3 is greater than 0.3, the electron-accepting material with a large refractive index (M oO3), the refractive index of the hole injection layer 111 is large, so the light extraction efficiency is On the other hand, when the volume ratio of MoO3 is greater than 0 and less than 0.3, In the lower region, the effect of the electron-accepting material (MoO3) with a large refractive index is small, and the refractive index is The refractive index of the electron donor material is smaller than that of the electron acceptor material (MoO3). This strongly influences the refractive index of 1, suggesting that the light extraction efficiency is good. That is, when the volume ratio of MoO3 in the hole injection layer 111 is greater than 0 and is equal to or less than 0.3, By using this, a light emitting device with good light extraction efficiency can be fabricated. EXAMPLES

[0374] In this embodiment, a light-emitting element different from that in the first embodiment is used as an electronic device according to one aspect of the present invention. A manufacturing example of the light-emitting element and characteristics of the light-emitting element will be described. The refractive index of the organic compound and the refractive index of the hole injection layer are explained. Also, the details of the element structure are shown. The structures and abbreviations of the compounds used are shown below. For other organic compounds, Please refer to Example 1 above.

[0375] [ka]

[0376] [Table 7]

[0377] [Table 8]

[0378] [Table 9]

[0379] <Refractive index measurement> Comparative light-emitting element 19 to comparative light-emitting element 22, light-emitting element 23 to light-emitting element 26, and light-emitting element 2 The refractive indexes of the organic compounds used in the hole injection layers 111 of the light-emitting elements 7 to 30 were measured. The measurement was carried out in the same manner as in Example 1.

[0380] The results of measuring the refractive index of each film using light with a wavelength of 532 nm are shown in Figure 19. DBT3P-II used in the light-emitting element 19 to the comparative light-emitting element 22 has the highest refractive index. It was found that the 9-[3-(9-phenyl -9H-fluoren-9-yl)phenyl]-9H-carbazole (abbreviation: mCzFLP It has been found that the n Ordinary is 1.75 or less, which is a low refractive index organic compound. In addition, the 4,4'-[bis(9-phenyl Fluoren-9-yl)]-triphenylamine (abbreviation: FLP2A) is an It was found that the organic compound had a low refractive index with an ary of 1.75 or less.

[0381] In addition, from the results of Example 1, the hole injection layer 111 of the light-emitting elements 23 to 30, The mixed films of mCzFLP or FLP2A and MoO3 have similar refractive index to the respective organic compounds. The hole injection layer 111 of the comparative light-emitting element 19 to the comparative light-emitting element 22 has a DBT3P It is expected that the refractive index will be lower than that of the mixed film of -II and MoO3.

[0382] <Fabrication of light-emitting element> <Fabrication of Comparative Light-Emitting Elements 19 to 22> The manufacturing process of the comparative light-emitting element 19 to the comparative light-emitting element 22 is the same as that of the comparative light-emitting element 1 to the comparative light-emitting element 22. The manufacturing process of the semiconductor device 4 differs from that of the semiconductor device 4 only in the manufacturing process of the hole injection layer 111 and the light emitting layer 130. The same procedure was carried out for comparative light-emitting elements 1 to 4.

[0383] On the electrode 101, a hole injection layer 111 was formed by dissolving DBT3P-II and MoO3 in a weight ratio of ( The ratio of DBT3P-II:MoO3 was 2:0.5 and the thickness was 1 nm. The value of z1 differs for each light-emitting element. The values ​​are shown in Table 8.

[0384] Next, on the hole transport layer 112, a light emitting layer 130(1) was formed by CCP and Ir(ppy)3 were mixed in a weight ratio of 4,6mCzP2Pm:PCCP:Ir(ppy) 3) were co-evaporated to a thickness of 20 nm in a ratio of 0.5:0.5:0.1. Then, as the light-emitting layer 130(2), a mixture of 4.6mCzP2Pm:PCCP:Ir( ppy)3) to be 0.8:0.2:0.1 and the thickness to be 20 nm In the light-emitting layer 130(1) and the light-emitting layer 130(2), Ir(ppy ) 3 is a guest material that exhibits phosphorescence.

[0385] <Fabrication of Light-emitting Elements 23 to 26> The manufacturing process of the light-emitting elements 23 to 26 is the same as that of the comparative light-emitting elements 19 to 22. The manufacturing process of the light-emitting element 11 is different from that of the light-emitting element 19. The same procedure was carried out as for the comparative light-emitting element 22.

[0386] On the electrode 101, a hole injection layer 111(1) was formed by dissolving mCzFLP and MoO3 in a weight ratio of ( The ratio of mCzFLP:MoO3 was 2:0.5 and the thickness was 35 nm. Then, DBT3P-II and MoO3 were co-evaporated in a weight ratio of (DBT3P-II:Mo O3) was co-evaporated to a thickness of 2 nm. The value of z2 differs for each light-emitting element, and the value of z2 for each light-emitting element is shown in Table 9. do.

[0387] <Fabrication of Light-emitting Elements 27 to 30> The manufacturing process of the light-emitting elements 27 to 30 is the same as that of the comparative light-emitting elements 19 to 22. The manufacturing process of the light-emitting element 11 is different from that of the light-emitting element 19. The same procedure was carried out as for the comparative light-emitting element 22.

[0388] On the electrode 101, a hole injection layer 111(1) was formed by dissolving FLP2A and MoO3 in a weight ratio of (F The ratio of LP2A:MoO3 was 2:0.5 and the thickness was 35 nm. Then, DBT3P-II and MoO3 were mixed in a weight ratio (DBT3P-II:MoO3 The mixture was co-deposited so that the ratio of the metals was 2:0.5 and the thickness was z2 nm. The value of z2 differs for each light-emitting element, and is shown in Table 9.

[0389] <Characteristics of light-emitting element> Next, the comparative light-emitting elements 19 to 22 and the light-emitting elements 23 to The characteristics of the element 30 were measured. The measurements were carried out in the same manner as in Example 1.

[0390] Among the light-emitting devices fabricated, the current efficiencies of the comparative light-emitting device 19, the light-emitting device 23, and the light-emitting device 27 were The efficiency-luminance characteristics are shown in FIG. 20. The current density-voltage characteristics are shown in FIG. 21. The external quantum efficiency vs. luminance characteristics are shown in Figure 22. Note that the external quantum efficiency values ​​shown in Figure 22 are corrected for viewing angles. The external quantum efficiency is measured from the front direction of the light emitting element, without any measurement. The comparative light-emitting element 19 uses DBT3P-II as an organic compound in the hole injection layer 111, The light-emitting element 23 is an element using mCzFLP, and the light-emitting element 27 is an element using FLP2A. All parts other than the injection layer 111 have the same device structure.

[0391] As can be seen from FIG. 21, the comparative light-emitting element 19, the light-emitting element 23, and the light-emitting element 27 have equivalent current density-voltage characteristics. Therefore, similarly to Example 1, the hole injection layer 111 had a refractive index of 1.0 μm. It was found that even an organic compound having a low molecular weight had good hole injection properties.

[0392] 20 and 22, the comparative light-emitting element 19, the light-emitting element 23, and the light-emitting element 27 are 100 It has been found that it has a high current efficiency of around cd / A and a high external quantum efficiency of over 25%. In addition, mCzFLP and FLP2A, which are organic compounds with low refractive index, were used as the hole injection layer 1. The light-emitting element 23 and the light-emitting element 27 used in the device 11 are made of DBT3P-II, which is a material with a high refractive index. The efficiency was higher than that of the comparative light-emitting element 19 used.

[0393] In addition, the comparative light-emitting element 19, the light-emitting element 23, and the light-emitting element 27 were each rated at 25 mA / cm 2 At a current density of The emission spectrum when a current was applied is shown in FIG. 23. As shown in FIG. 23, the comparative light-emitting element 1 The emission spectra of the light-emitting elements 23 and 27 have a peak at about 518 nm. This is due to the emission of Ir(ppy)3, which is a guest material contained in the light-emitting layer 130. It was found that...

[0394] In addition, one of the comparative light-emitting elements 19 to 22 and the light-emitting elements 23 to 30 000cd / m 2 The device characteristics in this region are shown in Table 10.

[0395] [Table 10]

[0396] From the above results, the comparative light-emitting elements 19 to 22 and the light-emitting element The light-emitting devices 23 to 30 have good driving voltage and light-emitting efficiency regardless of the structure of the hole injection layer 111. It can be seen that it shows the ratio.

[0397] <Relationship between refractive index of hole injection layer 111 and external quantum efficiency> Using the values ​​of each element shown in Table 10 in FIG. 24, the organic materials used in each hole injection layer 111 were The relationship between chromaticity x and external quantum efficiency is shown in Figure 24. The data shows the values ​​of the comparative light-emitting elements 19 to 22, and the data of the curve of "mCzFLP". The data of the curve of "FLP2A" is the value of the light emitting element 23 to the light emitting element 26. The values ​​of luminous elements 27 to 30 were used, respectively.

[0398] As shown in FIG. 19, the organic compounds used in the hole injection layer 111 are DBT3P-II>mCzFLP>F As shown in FIG. 24, the refractive index of the hole injection layer 111 is higher in the order of LP, LP2, and A. It was found that the lower the refractive index of the organic compound, the higher the external quantum efficiency. This is because the attenuation of light due to the light-extracting mode is reduced, improving the light extraction efficiency.

[0399] As described above, by using an organic compound with a low refractive index for the hole injection layer 111, the hole injection characteristics It was found that a light emitting device having good light extraction efficiency while maintaining the above properties could be obtained. EXAMPLES

[0400] Example 1 In this example, a manufacturing example of a light-emitting element, which is one type of electronic device according to one embodiment of the present invention, and The characteristics of the light-emitting element will be described. In addition, the refractive index and The refractive index of the hole injection layer will be described. A cross-sectional view of the device structure produced in this example is shown in FIG. The details of the device structure are shown in Tables 11 to 14. The structures of the compounds used are shown in Tables 11 to 14. The structures and abbreviations may be found in the above-mentioned embodiments and examples.

[0401] [Table 11]

[0402] [Table 12]

[0403] [Table 13]

[0404] [Table 14]

[0405] <Refractive index measurement> Comparative light-emitting element 31 to comparative light-emitting element 34, light-emitting element 35 to light-emitting element 38, and light-emitting element 39 to light-emitting element 42, light-emitting element 43 to light-emitting element 46, and comparative light-emitting element 47 to comparative light-emitting element Organic Compound Used in the Hole Injection Layer 111 of No. 50 and Comparative Light-Emitting Element 31 to Comparative Light-Emitting Element 34 , light-emitting element 35 to light-emitting element 38, light-emitting element 39 to light-emitting element 42, light-emitting element 43 to light-emitting element 44, The refraction of the hole injection layer 111 used in the optical element 46 and the comparative light-emitting elements 47 to 50 The refractive index was measured in the same manner as in Example 1.

[0406] The results of measuring the refractive index of each film using light with a wavelength of 532 nm are shown in Figure 25. DBT3P-II used in the light-emitting element 31 to the comparative light-emitting element 34 has the highest refractive index. It was found that the CzC used in the light-emitting elements 35 to 38 and the light-emitting elements 39 to CzSi used in the light-emitting element 42, FATPA used in the light-emitting elements 43 to 46, The 1,4-di(triphenylsilyl)benzene used in the comparative light-emitting elements 47 to 50 UGH-2 (abbreviation: UGH-2) has a refractive index of 1.70 or less for all n Ordinary It was found that the organic compounds were very low in

[0407] In addition, the hole injection layer 111 is required to have a hole injection property, and therefore, it is preferable that the layer contains an electron donating material. It is preferable that the hole injection layer of each light-emitting element uses MoO3 having a high refractive index as an electron donor material. 111 is expected to have a high refractive index. However, as shown in FIG. The refractive index of the film in which MoO3, which is 11, is added to each organic compound is It was found that the refractive index of the hole injection layer 111 was slightly higher than that of the material. By using a material with low refractive index and electron donating property, It was found that a hole injection layer 111 with a low refractive index can be obtained even if a material with a high refractive index is mixed.

[0408] In addition, as shown in FIG. 25, the hole injection layer 111 of each light emitting element has a thickness of n It was found that the difference between Ordinary and n Extraordinary was small. That is, the mixed film of the electron donating material MoO3 and organic compounds has different properties compared to the organic compound film. It was found that the directional property decreased.

[0409] In addition, the organic compound Cz Si and the organic compound used in the hole injection layer 111 of the comparative light-emitting elements 47 to 50 The mixed film of UGH-2 and MoO3 has a refractive index similar to that of each organic compound, The hole injection layer 111 of the comparative light-emitting element 1 to the comparative light-emitting element 4 is composed of DBT3P-II and MoO3 It is expected that the refractive index will be lower than that of the mixed film of .

[0410] <Fabrication of light-emitting element> <Fabrication of Comparative Light-Emitting Elements 31 to 34> 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).

[0411] Next, 1,3,5-tri-(4-dibenzothiophene) was deposited on the electrode 101 as a hole injection layer 111. DBT3P-II) and MoO3 were mixed in a weight ratio of (DBT The ratio of 3P-II:MoO3 was 2:0.5 and the thickness was x3 nm. The value of x3 differs for each light-emitting element. The values ​​are shown in Table 13.

[0412] Next, a hole transport layer 112 was formed on the hole injection layer 111 by depositing PCCP to a thickness of 20 nm. The deposition was carried out so that

[0413] Next, on the hole transport layer 112, a light emitting layer 130(1) was formed by CCP and Ir(ppy)3 were mixed in a weight ratio of 4,6mCzP2Pm:PCCP:Ir(ppy) 3) were co-evaporated to a thickness of 20 nm in a ratio of 0.5:0.5:0.1. Then, as the light-emitting layer 130(2), a mixture of 4.6mCzP2Pm:PCCP:Ir( ppy)3) to be 0.8:0.2:0.1 and the thickness to be 20 nm In the light-emitting layer 130(1) and the light-emitting layer 130(2), Ir(ppy ) 3 is a guest material that exhibits phosphorescence.

[0414] Next, a 4.6mCz P2Pm was co-deposited to a thickness of 20 nm. As a second electron transport layer 118(2), bathophenanthroline (abbreviation: BPhe n) was evaporated to a film thickness of 10 nm.

[0415] Next, a lithium fluoride ( LiF) was evaporated to a thickness of 1 nm.

[0416] 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.

[0417] Next, the device is sealed using an organic EL sealing material in a nitrogen atmosphere glove box. The glass substrate for the organic material was fixed to the glass substrate on which the organic material was formed, and the comparative light-emitting element 3 was formed. Specifically, the organic material was formed on a glass substrate. A sealing material is applied around the substrate, and the substrate and a glass substrate for sealing are attached to each other. 6 J / cm of ultraviolet light with a wavelength of 365 nm 2 The film was irradiated with light and then heat-treated at 80°C for 1 hour. Through this process, comparative light-emitting elements 31 to 34 were obtained.

[0418] <Fabrication of Light-emitting Elements 35 to 46 and Comparative Light-emitting Elements 47 to 50> The processes for fabricating the light-emitting elements 35 to 46 and the comparative light-emitting elements 47 to 50 are as follows: The steps of fabricating the comparative light-emitting elements 31 to 34 and the step of fabricating the hole injection layer 111 The other steps were performed in the same manner as in the comparative light-emitting element 31 to the comparative light-emitting element 34. The details of the preparation method are as shown in Tables 11 to 14, so the details of the preparation method are omitted.

[0419] <Characteristics of light-emitting element> Next, the comparative light-emitting elements 31 to 34, the light-emitting elements 35 to The characteristics of the light-emitting element 46 and the comparative light-emitting elements 47 to 50 were measured. Did the same.

[0420] Among the light-emitting devices thus fabricated, comparative light-emitting device 31, light-emitting device 35, light-emitting device 39, and light-emitting device FIG. 26 shows current efficiency vs. luminance characteristics of the light-emitting element 43 and the comparative light-emitting element 47. The voltage characteristics are shown in Fig. 27. The external quantum efficiency-luminance characteristics are shown in Fig. 28. The external quantum efficiency values ​​shown are not corrected for viewing angles and are measured from the front of the light-emitting element. The external quantum efficiency is shown in FIG. The element 31 is DBT3P-II, the light-emitting element 35 is CzC, the light-emitting element 39 is CzSi, The optical element 43 is an element using FATPA, and the comparative light emitting element 47 is an element using UGH-2. All the parts other than the hole injection layer 111 have the same device structure.

[0421] 26 and 28, the comparative light-emitting element 31, the light-emitting element 35, the light-emitting element 39, and the light-emitting element 43 The comparative light-emitting element 47 has a high current efficiency of more than 90 cd / A and a high external It was found that the quantum efficiency was high. In addition, the organic compound with a low refractive index was used as the hole injection layer 11. The light-emitting element 35, the light-emitting element 39, the light-emitting element 43, and the comparative light-emitting element 47 used in Example 1 have a refractive index of The efficiency was higher than that of the comparative light-emitting device 31, which uses DBT3P-II, a material with high optical properties. This is because the hole injection layer 111 is made of an organic compound with a small refractive index, This suggests that the attenuation of light due to the ion beam is suppressed.

[0422] In addition, as shown in FIG. 27, the comparative light-emitting element 31, the light-emitting element 35, the light-emitting element 39, and the light-emitting element 43 It was found that the light-emitting element 47 had the same excellent current density-voltage characteristics. is compared with the comparative light-emitting element 31, the light-emitting element 35, the light-emitting element 39, and the light-emitting element 43. The voltage characteristics were reduced, and it was found that the hole injection ability was low. This is because UGH-2 has a molecular This is because the molecule does not have an electron-donating group. Therefore, even if a material with a small refractive index is used for the hole injection layer 111, good hole injection characteristics are obtained. It was found that the hole injection layer 111 could be fabricated.

[0423] In addition, the comparative light-emitting element 31, the light-emitting element 35, the light-emitting element 39, the light-emitting element 43, and the comparative light-emitting element 25mA / cm at 47 2 The emission spectrum when a current was applied at a current density of As shown in FIG. 29, the comparative light-emitting element 31, the light-emitting element 35, the light-emitting element 39, the light-emitting element 43, and The emission spectrum of the comparative light-emitting element 47 has a peak at about 518 nm. It was found that this was due to the emission of Ir(ppy)3, a guest material contained in 130. I did.

[0424] In addition, the comparative light-emitting element 31 to the comparative light-emitting element 34, the light-emitting element 35 to the light-emitting element 46, and the comparative light-emitting element Comparative light emitting element 47 to comparative light emitting element 50: 1000 cd / m 2 The device characteristics in the vicinity are shown in Table 1. 5. The external quantum efficiency shown in Table 15 is the external quantum efficiency after viewing angle correction.

[0425] [Table 15]

[0426] From the above results, the comparative light-emitting elements 31 to 34 and the light-emitting element 3 The light-emitting elements 5 to 46 and the comparative light-emitting elements 47 to 50 have a hole injection layer 111 It is clear that, regardless of the structure, good driving voltage and luminous efficiency are exhibited.

[0427] <Reliability of light-emitting elements> Next, the comparative light-emitting element 31, the light-emitting element 35, the light-emitting element 39, the light-emitting element 43, and the comparative light-emitting element A constant current drive test was conducted at 2 mA for the 47. The results are shown in Figure 30. From Figure 30, The reliability of the comparative light-emitting element 31, the light-emitting element 35, the light-emitting element 39, and the light-emitting element 43 was It was found that the reliability of the light-emitting element 43 was better than that of the light-emitting element 47. As described above, the comparative light-emitting element 31, the light-emitting element 35, the light-emitting element 39, The organic compound used in the hole injection layer 111 of the optical element 43 has an electron donating group in the molecule. Therefore, the hole injection property is better than that of UGH-2 used in the comparative light-emitting element 47. Therefore, the better the hole injection property of the hole injection layer 111, the higher the reliability of the light emitting device. In addition, in FIG. 30, the comparative light-emitting element 31 and the light-emitting element 35 The reliability test results of the light-emitting element 39 overlap.

[0428] <Relationship between refractive index of hole injection layer 111 and external quantum efficiency> Using the values ​​of each element shown in Table 15, the organic material used in each hole injection layer 111 is The relationship between chromaticity x and external quantum efficiency is shown in Figure 31. The data shows the values ​​of the comparative light emitting elements 31 to 34, and the data of the curve "CzC" shows the values ​​of the comparative light emitting elements 31 to 34. The values ​​of light emitting element 35 to light emitting element 38 are shown in the data of the "CzSi" curve, and light emitting elements 39 to The value of light-emitting element 42 is shown in the "FATPA" curve data, and light-emitting elements 43 to 46 are shown. The data of the curve of "UGH-2" is the values ​​of the comparative light-emitting element 47 to the comparative light-emitting element 50. were used, respectively.

[0429] As shown in Figure 25, the organic compound DBT3P-II used in the hole injection layer 111 has a refractive index of 1. Although it has a high refractive index of over 80, CzC, CzSi, FATPA, and UGH-2 It is an organic compound with a low refractive index of 1.70 or less. The hole injection layer 111 is formed of an organic compound having a lower refractive index than the light emitting element. It was found that the light-emitting device using the evanescent current has a higher external quantum efficiency. This is because the attenuation of light due to the diffuse emission mode is reduced, improving the light extraction efficiency.

[0430] As described above, the hole injection layer 111 has a tetraarylmethane skeleton or a tetraarylsilane skeleton. By using either one of them and an organic compound having an electron donating group, the hole injection characteristic can be improved. It has been found that a light-emitting element having good light extraction efficiency and good reliability can be obtained while maintaining the excellent light-emitting property. I did. EXAMPLES

[0431] Example 1 In this example, a manufacturing example of a light-emitting element, which is one type of electronic device according to one embodiment of the present invention, and The characteristics of the light-emitting element will be described. In addition, the refractive index and The refractive index of the hole injection layer will be described. A cross-sectional view of the device structure produced in this example is shown in FIG. The details of the device structure are shown in Tables 16 and 17. The structures and abbreviations of the compounds used are shown in Tables 16 and 17. The names of the organic compounds are shown below. For other organic compounds, refer to the previous examples and embodiments. In the light-emitting element shown in this embodiment, a metal oxide is not used for the hole injection layer 111, but a metal oxide is used for the hole injection layer 111. It is composed only of mechanical compounds.

[0432] [ka]

[0433] [Table 16]

[0434] [Table 17]

[0435] <Refractive index measurement> Comparative light-emitting element 51 to comparative light-emitting element 54, comparative light-emitting element 55 to comparative light-emitting element 58, Refractive index of the hole injection layer 111 of the element 59 to the light emitting element 62 and the light emitting element 63 to the light emitting element 66 The refractive index was measured in the same manner as in Example 1. The refractive index (n Ordinary) of each film in light is shown in Table 18.

[0436] [Table 18]

[0437] From Table 18, the N,N,N',N'-tetramethylphenyl ether used in the comparative light-emitting element 51 to the comparative light-emitting element 54 is β-TNB and p-dopant (analysis) The mixed film of NP (purchased from Epson Corporation) and the NP used in the comparative light-emitting element 55 to the comparative light-emitting element 58 The mixed film of B and p-dopant has a high refractive index, which is greater than 1.75. On the other hand, the BPAFLP and p-dop The mixed film of ant and TAPC and p-dopan used in the light-emitting devices 63 to 66 The refractive index of the mixed film of t was found to be lower than 1.75, which is a low refractive index. .

[0438] <Fabrication of light-emitting element> <Fabrication of Comparative Light-Emitting Elements 51 to 54> 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).

[0439] Next, as the hole injection layer 111, β-TNB, a p-dopant, and The weight ratio (β-TNB:p-dopant) was 1:0.01 and the thickness was 6 The film was co-evaporated to a thickness of 0 nm.

[0440] Next, a hole transport layer 112 made of PCBBiF was deposited to a thickness of 1 nm on the hole injection layer 111. The value of z1 differs for each light-emitting element. The value of z1 is shown in Table 17.

[0441] Next, 2mDBTBPDBq-II was added as the light-emitting layer 130(1) on the hole transport layer 112. PCBBiF and Ir(dppm)2(acac) in a weight ratio of (2mDBTBPD Bq-II:PCBBiF:Ir(dppm)2(acac)) is 0.7:0.3:0. Then, the emitting layer 130 (2 ) as the weight ratio (2mDBTBPDBq-II:PCBBiF:Ir(dppm)2( The ratio of acac) was 0.8:0.2:0.06 and the thickness was 20 nm. In the light-emitting layer 130(1) and the light-emitting layer 130(2), Ir(dp pm)2(acac) is a guest material that exhibits phosphorescence.

[0442] Next, on the light-emitting layer 130(2), 2mDBTB was deposited as the first electron transport layer 118(1). PDBq-II was co-deposited to a thickness of 20 nm. 18(1) was coated with 2,9-bis(naphthalene-2- NBPhen) was used as a membrane The deposition was carried out to a thickness of 20 nm.

[0443] Next, a lithium fluoride ( LiF) was evaporated to a thickness of 1 nm.

[0444] 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.

[0445] Next, the device is sealed using an organic EL sealing material in a nitrogen atmosphere glove box. The glass substrate for the comparative light-emitting element 5 was fixed to the glass substrate on which the organic material was formed. Specifically, the organic material was formed on a glass substrate. A sealing material is applied around the substrate, and the substrate and a glass substrate for sealing are attached to each other. 6 J / cm of ultraviolet light with a wavelength of 365 nm 2 The film was irradiated with light and then heat-treated at 80°C for 1 hour. Through this process, comparative light-emitting elements 51 to 54 were obtained.

[0446] <Fabrication of Comparative Light-Emitting Elements 55 to 58 and Light-Emitting Elements 59 to 66> The manufacturing process of the comparative light-emitting element 55 to the comparative light-emitting element 58 and the light-emitting element 59 to the light-emitting element 66 is as follows: The steps of fabricating the comparative light-emitting elements 51 to 54 and the step of fabricating the hole injection layer 111 The other steps were performed in the same manner as in the comparative light-emitting element 51 to the comparative light-emitting element 54. The details of the preparation method are as shown in Tables 16 and 17, so the details of the preparation method are omitted.

[0447] <Characteristics of light-emitting element> Next, the comparative light-emitting elements 51 to 58 and the light-emitting elements 59 to The characteristics of the element 66 were measured. The measurements were carried out in the same manner as in Example 1. 2 Nearby The characteristics of each element in Table 19 are shown. The external quantum efficiency shown in Table 19 is the value before viewing angle correction. The external quantum efficiency is shown.

[0448] [Table 19]

[0449] From the above results, the comparative light-emitting elements 51 to 58 and the light-emitting element The light-emitting elements 59 to 66 have good driving voltage and light-emitting efficiency regardless of the structure of the hole injection layer 111. It can be seen that it shows the ratio.

[0450] <Relationship between refractive index of hole injection layer 111 and external quantum efficiency> Using the values ​​of each element shown in Table 19 in FIG. 32, the organic material used in each hole injection layer 111 The relationship between chromaticity y and external quantum efficiency is shown in Figure 32. The values ​​of the comparative light emitting elements 51 to 54 are shown in the data of the "NPB" curve. The values ​​of the light emitting element 55 to the comparative light emitting element 58 are shown in the data of the curve of "BPAFLP". The values ​​for light emitting element 9 to 62 are shown in the "TAPC" curve data for light emitting element 63 to 62. A value of 66 was used.

[0451] From Table 18, when β-TNB and NPB were used in the hole injection layer 111, The refractive index is high, exceeding 1.75, but when BPAFLP and TAPC are used In this case, the refractive index of the hole injection layer 111 is low, 1.75 or less. When comparing the external quantum efficiency of each light-emitting element with a y chromaticity of around 0.435, the hole injection It was found that the light-emitting device having the layer 111 had a higher external quantum efficiency. At the same chromaticity, the light-emitting element having the hole injection layer 111 with a lower refractive index has better light emission. This is because the attenuation of light due to the evanescent mode is reduced. This is because the light extraction efficiency has been improved.

[0452] (Reference example 1) In this reference example, the synthesis method of Ir(pbi-diBuCNp)3 used in Example 1 is described. I will explain it below.

[0453] <Step 1: Synthesis of 4-amino-3,5-diisobutylbenzonitrile> 4-Amino-3,5-dichlorobenzonitrile 52g (280mmol), isobutyl benzoate Sodium phosphate 125g (1226mmol), potassium phosphate tripotassium phosphate 260g (1226mmol) , 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (S-phos ) 5.4g (13.1mmol) and 1500mL of toluene in a 3000mL three-neck flask. The atmosphere in the flask was replaced with nitrogen, and the mixture was stirred while the pressure in the flask was reduced, and the mixture was degassed. After degassing, 4.8 g (5.2 ml) of tris(dibenzylideneacetone)dipalladium(0) was added. mol) was added and the mixture was stirred at 130° C. for 12 hours under a nitrogen stream. Add cellulose and use Celite (Wako Pure Chemical Industries, Ltd., catalog number: 531-16855) / Florisil (Wako Pure Chemical Industries, Ltd., Catalog number: 540-00135) / Al oxide The mixture was filtered through a filter aid layered in order of thickness, thickness, and thickness of the filter aid. The filtrate was concentrated to give an oily solution. The oily product was purified by silica column chromatography. Toluene was used. The obtained fraction was concentrated to give 61 g of a yellow oily product in yield. The yellow oil obtained was 4-amino-3,5 -diisobutylbenzonitrile. The synthesis scheme for step 1 is shown below. As shown in formula (a-1).

[0454] [ka]

[0455] Step 2: 4-[N-(2-nitrophenyl)amino]-3,5-diisobutylbenzene Synthesis of zonitrile> 30 g of 4-amino-3,5-diisobutylbenzonitrile (131 mmol), cesium carbonate 86g (263mmol), dimethyl sulfoxide (DMSO ) 380mL, 19g (131mmol) of 2-fluoronitrobenzene in 1000mL The mixture was placed in a flask and stirred at 120°C for 20 hours under a nitrogen stream. The liquid was extracted with chloroform to obtain a crude product. The product was purified by chromatography using a 7:1 mixture of hexane and ethyl acetate as the developing solvent. The obtained fraction was concentrated to give an orange solid. Hexane was added to the obtained solid to give an orange solid. The mixture was filtered under suction to give 16 g of a yellow solid in 35% yield. The resulting yellow solid was 4-[N-(2-nitrophenyl)amino]-3,5-diisobutyl It was confirmed that the compound was benzonitrile. The synthesis scheme for step 2 is shown in the following formula (a-2). show.

[0456] [ka]

[0457] <Step 3: 4-[N-(2-aminophenyl)amino]-3,5-diisobutylbenzene Synthesis of zonitrile> 4-[N-(2-nitrophenyl)amino]-3,5-diisobutene synthesized in step 2 21 g (60.0 mmol) of dibenzonitrile, 11 mL (0.6 mol) of water, and ethanol. 780 mL of tin chloride (I) was added to a 2000 mL three-neck flask and stirred. I) 57 g (0.3 mol) was added and stirred at 80° C. for 7.5 hours under a nitrogen stream. After this time, the mixture was poured into 400 mL of 2 M aqueous sodium hydroxide solution and incubated at room temperature for 16 hours. The mixture was stirred. The precipitate was removed by suction filtration, and then washed with chloroform. The filtrate was extracted with chloroform. Concentration gave a white solid, 20 g, in 100% yield. The white solid was 4-[N-(2-aminophenyl)amino]-3,5-diisobutylbenzoyl The synthesis scheme of step 3 is shown in the following formula (a-3).

[0458] [ka]

[0459] <Step 4; 1-(4-cyano-2,6-diisobutylphenyl)-2-phenyl-1 Synthesis of H-benzimidazole (abbreviation: Hpbi-diBuCNp) 4-[N-(2-aminophenyl)amino]-3,5-diisobutene synthesized in step 3 20 g (60.0 mmol) of dibenzonitrile, 200 mL of acetonitrile, Add 6.4 g (60.0 mmol) of aldehyde to a 1000 mL eggplant flask and heat at 100°C for 1 The mixture was stirred for 1 hour. 100 mg (0.60 mmol) of iron(III) chloride was added to the mixture. The mixture was stirred at 100°C for 24 hours. After the specified time had elapsed, the reaction solution was extracted with chloroform. Toluene was added to the oily product, and the mixture was washed with celite / florisil / acid. The mixture was filtered through a filter aid layered with aluminum chloride in order by suction. The filtrate obtained was concentrated. The oily product was purified by silica column chromatography. Toluene was used as the decomposition solvent. The obtained fraction was concentrated to obtain a solid. The product was recrystallized from ethyl acetate / hexane to give the desired white solid (4.3 g, yield: The white solid obtained by nuclear magnetic resonance (NMR) was 1-(4-cyano-2 ,6-diisobutylphenyl)-2-phenyl-1H-benzimidazole (abbreviation: Hp The synthesis scheme of step 4 is shown below. -4).

[0460] [ka]

[0461] Step 5: Tris{2-[1-(4-cyano-2,6-diisobutylphenyl)-1 H-Benzimidazol-2-yl-κN 3 ]phenyl-κC}iridium(III)( Synthesis of Ir(pbi-diBuCNp)3) 1-(4-cyano-2,6-diisobutylphenyl)-2-phenylene synthesized in step 4 Hpbi-diBuCNp 1.8g (4.4mg) mol), tris(acetylacetonato)iridium(III) 0.43 g (0.88 m The resulting mixture was placed in a reaction vessel equipped with a three-way cock and heated at 250°C for 39 hours. Toluene was added to the reaction mixture, and insoluble matter was removed. The obtained filtrate was concentrated to remove the solid. The obtained solid was purified by silica column chromatography (neutral silica). Toluene was used as the developing solvent. The obtained fraction was concentrated to obtain a solid. The solid was recrystallized from ethyl acetate / hexane to give a yellow solid (0.26 g, 21% yield). The synthesis scheme is shown in the following formula (a-5).

[0462] [ka]

[0463] The proton ( 1 H) was measured by nuclear magnetic resonance (NMR). From the measurement results, in this reference example, Ir(pbi-diBuCNp)3 (fac form and me It was found that a mixture of r-isomers was obtained. 1 From H-NMR, the fac form and It was confirmed that the compound was a mixture of mer isomers. The isomer ratio was fac:mer = 3:2. It was found that the proportion of [Explanation of symbols]

[0464] 10: substrate, 11: electrode, 12: electrode, 15: substrate, 20: organic semiconductor layer, 30: carrier A transport layer, 40: functional layer, 50: electronic device, 100: EL layer, 101: electrode, 102 : electrode, 106: light emitting unit, 108: light emitting unit, 110: light emitting unit, 111 : hole injection layer, 112: hole transport layer, 113: electron transport layer, 114: electron injection layer, 115 : charge generation layer, 116: hole injection layer, 117: hole transport layer, 118: electron transport layer, 119 : electron injection layer, 120: light emitting layer, 121: guest material, 122: host material, 130: light emitting layer Optical layer, 131: guest material, 131_1: organic compound, 131_2: organic compound, 132 : host material, 134: light-emitting region, 140: light-emitting layer, 141: guest material, 142: host a light-emitting material, 142_1: an organic compound, 142_2: an organic compound, 150: a light-emitting element, 170 : Light emitting layer, 200: Substrate, 250: Light emitting element, 252: Light emitting element, 601: Source side driving Circuit, 602: pixel section, 603: gate side driving circuit, 604: sealing substrate, 605: seal material, 607: space, 608: wiring, 610: element substrate, 611: switching TFT, 612: Current control TFT, 613: Electrode, 614: Insulator, 616: EL layer, 617: Electrode, 618: Light-emitting element, 623: n-channel TFT, 624: p-channel TFT, 900: portable information terminal, 901: housing, 902: housing, 903: display unit, 905: hinge unit, 910: portable information terminal, 911: housing, 912: display unit, 913: operation button, 91 4: External connection port, 915: Speaker, 916: Microphone, 917: Camera, 920: Camera Camera, 921: Housing, 922: Display, 923: Operation buttons, 924: Shutter button 926: lens; 1001: substrate; 1002: base 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: electrode, 1024G: electrode , 1024R: Electrode, 1024W: Electrode, 1025B: Lower electrode, 1025G: Lower electrode , 1025R: lower electrode, 1025W: lower electrode, 1026: partition wall, 1028: EL layer, 1029: electrode, 1031: sealing substrate, 1032: sealing material, 1033: base material, 1034 B: colored layer, 1034G: colored layer, 1034R: colored layer, 1036: overcoat layer, 1037: interlayer insulating film, 1040: pixel section, 1041: driving circuit section, 1042: peripheral section, 3054: display unit, 3500: multi-function terminal, 3502: housing, 3504: display unit, 350 6: Camera, 3508: Lighting, 3600: Light, 3602: Housing, 3608: Lighting, 3 610: speaker, 8501: lighting device, 8502: lighting device, 8503: lighting device, 8 504: lighting device, 9000: housing, 9001: display unit, 9003: speaker, 9005 : Operation key, 9006: Connection terminal, 9007: Sensor, 9008: Microphone, 90 55: hinge, 9200: mobile information terminal, 9201: mobile information terminal, 9202: mobile information Terminal

Claims

1. A light-emitting device comprising a first layer, a second layer, and a light-emitting layer between a first electrode and a second electrode, the first layer is located between the first electrode and the light-emitting layer; the first layer includes a first organic compound having a pyrrole skeleton and a tetraarylmethane skeleton or a tetraarylsilane skeleton; the second layer is located between the first layer and the light-emitting layer; the second layer includes a second organic compound having a pyrrole skeleton, A light-emitting device, wherein the second organic compound has a higher ordinary refractive index when formed into a thin film than the first organic compound has a higher ordinary refractive index when formed into a thin film.

2. A light-emitting device comprising a first layer, a second layer, and a light-emitting layer between a first electrode and a second electrode, the first layer is located between the first electrode and the light-emitting layer; the first layer includes a first organic compound having a carbazole skeleton and a tetraarylmethane skeleton or a tetraarylsilane skeleton; the second layer is located between the first layer and the light-emitting layer; the second layer includes a second organic compound having a carbazole skeleton, A light-emitting device, wherein the second organic compound has a higher ordinary refractive index when formed into a thin film than the first organic compound has a higher ordinary refractive index when formed into a thin film.

3. A light-emitting device comprising a first layer, a second layer, and a light-emitting layer between a first electrode and a second electrode, the first layer is located between the first electrode and the light-emitting layer; the first layer includes a first organic compound having a pyrrole skeleton and a tetraarylmethane skeleton or a tetraarylsilane skeleton, and a first substance having an electron accepting property; the second layer is located between the first layer and the light-emitting layer; the second layer includes a second organic compound having a pyrrole skeleton, A light-emitting device, wherein the second organic compound has a higher ordinary refractive index when formed into a thin film than the first organic compound has a higher ordinary refractive index when formed into a thin film.

4. A light-emitting device comprising a first layer, a second layer, and a light-emitting layer between a first electrode and a second electrode, the first layer is located between the first electrode and the light-emitting layer; the first layer includes a first organic compound having a carbazole skeleton and a tetraarylmethane skeleton or a tetraarylsilane skeleton, and a first substance having an electron accepting property; the second layer is located between the first layer and the light-emitting layer; the second layer includes a second organic compound having a carbazole skeleton, A light-emitting device, wherein the second organic compound has a higher ordinary refractive index when formed into a thin film than the first organic compound has a higher ordinary refractive index when formed into a thin film.

5. A light-emitting device comprising a first layer, a second layer, and a light-emitting layer between a first electrode and a second electrode, the first layer is located between the first electrode and the light-emitting layer; the first layer includes a first organic compound having a pyrrole skeleton and a tetraarylmethane skeleton or a tetraarylsilane skeleton, and a first substance having at least one of a halogen group and a cyano group; the second layer is located between the first layer and the light-emitting layer; the second layer includes a second organic compound having a pyrrole skeleton, A light-emitting device, wherein the second organic compound has a higher ordinary refractive index when formed into a thin film than the first organic compound has a higher ordinary refractive index when formed into a thin film.

6. A light-emitting device comprising a first layer, a second layer, and a light-emitting layer between a first electrode and a second electrode, the first layer is located between the first electrode and the light-emitting layer; the first layer includes a first organic compound having a carbazole skeleton and a tetraarylmethane skeleton or a tetraarylsilane skeleton, and a first substance having at least one of a halogen group and a cyano group; the second layer is located between the first layer and the light-emitting layer; the second layer includes a second organic compound having a carbazole skeleton, A light-emitting device, wherein the second organic compound has a higher ordinary refractive index when formed into a thin film than the first organic compound has a higher ordinary refractive index when formed into a thin film.

7. A light-emitting device comprising a first layer, a second layer, and a light-emitting layer between a first electrode and a second electrode, the first layer is located between the first electrode and the light-emitting layer; the first layer includes a first organic compound having a pyrrole skeleton and a tetraarylmethane skeleton or a tetraarylsilane skeleton, and a first substance having an electron accepting property; the second layer is located between the first layer and the light-emitting layer; the second layer includes a second organic compound having a pyrrole skeleton, A light-emitting device, wherein the ordinary refractive index of the second organic compound when formed into a thin film is higher than the ordinary refractive index of a thin film formed by mixing the first organic compound and the first substance.

8. A light-emitting device comprising a first layer, a second layer, and a light-emitting layer between a first electrode and a second electrode, the first layer is located between the first electrode and the light-emitting layer; the first layer includes a first organic compound having a carbazole skeleton and a tetraarylmethane skeleton or a tetraarylsilane skeleton, and a first substance having an electron accepting property; the second layer is located between the first layer and the light-emitting layer; the second layer includes a second organic compound having a carbazole skeleton, A light-emitting device, wherein the ordinary refractive index of the second organic compound when formed into a thin film is higher than the ordinary refractive index of a thin film formed by mixing the first organic compound and the first substance.

9. A light-emitting device comprising a first layer, a second layer, and a light-emitting layer between a first electrode and a second electrode, the first layer is located between the first electrode and the light-emitting layer; the first layer includes a first organic compound having a pyrrole skeleton and a tetraarylmethane skeleton or a tetraarylsilane skeleton, and a first substance having at least one of a halogen group and a cyano group; the second layer is located between the first layer and the light-emitting layer; the second layer includes a second organic compound having a pyrrole skeleton, A light-emitting device, wherein the ordinary refractive index of the second organic compound when formed into a thin film is higher than the ordinary refractive index of a thin film formed by mixing the first organic compound and the first substance.

10. A light-emitting device comprising a first layer, a second layer, and a light-emitting layer between a first electrode and a second electrode, the first layer is located between the first electrode and the light-emitting layer; the first layer includes a first organic compound having a carbazole skeleton and a tetraarylmethane skeleton or a tetraarylsilane skeleton, and a first substance having at least one of a halogen group and a cyano group; the second layer is located between the first layer and the light-emitting layer; the second layer includes a second organic compound having a carbazole skeleton, A light-emitting device, wherein the ordinary refractive index of the second organic compound when formed into a thin film is higher than the ordinary refractive index of a thin film formed by mixing the first organic compound and the first substance.

11. In any one of claims 1 to 10, A light-emitting device, wherein the first organic compound and the second organic compound are different compounds.

12. In any one of claims 1 to 11, A light-emitting device, wherein the ordinary refractive index is an ordinary refractive index at a wavelength of 532 nm.

13. In any one of claims 1 to 11, A light-emitting device, wherein the ordinary refractive index is an ordinary refractive index at a wavelength of 633 nm.

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