Light-emitting devices

Abstract

To provide an electronic device with high light extraction efficiency or light confinement effect.SOLUTION: An electronic device includes a first layer and a second layer between a first electrode and a second electrode. The first layer is located between the first electrode and the second layer. The first layer has a first organic compound and a first substance. The refractive index of a thin film of the first organic compound is between 1 and 1.75. The first substance has an electron-accepting property. The second layer has a light emitting or absorbing function.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, a light-emitting device, an electronic device, and Regarding lighting devices.

[0002] It should be noted that one aspect of the present invention is not limited to the above-mentioned technical fields. The present invention relates to a process, a machine, a manufacture, or 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 Regarding the method. [Background technology]

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

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

[0005] Such electronic devices are mainly formed with an organic semiconductor layer made of a thin film of organic compounds. Since the organic compound and layer structure have a significant effect on the organic semiconductor device, The selection of the layer structure is important. Furthermore, in organic solar cells and organic EL devices, In electronic devices that absorb light, structures with high light extraction efficiency and light confinement effect are important. It is essential.

[0006] Various methods have been proposed to improve the light extraction efficiency of organic EL elements. The light extraction efficiency is improved by creating an uneven shape on parts of the electrodes and EL layer. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-033706 Summary of the Invention [Problem to be solved by the invention]

[0008] In light-emitting devices such as organic EL devices, the substrate is used as a method for improving the light extraction efficiency. 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, in organic solar cells, the development of layers and layer structures with high light trapping effects is required. It is being considered.

[0009] In view of the above-described 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 with 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 one embodiment of the present invention is to provide a highly reliable electronic device. Another object of one embodiment of the present invention is to provide an electronic device with high light-emitting efficiency. Another object of the present invention is to provide a novel electronic device. Another object of the present invention is to provide an electron device having a high light trapping effect. Another object of one embodiment of the present invention is to provide a novel semiconductor device. The goal 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 can 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 aspect 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 refractive index of the thin film of the first organic compound is 1 or more and 1.75 or less, and the first substance is an electron The first layer has a light-receiving function, and the second layer has a light-emitting or light-absorbing function. .

[0012] 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 having 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 confinement effect of the electronic device.

[0014] In the above structure, the compound having a tetraarylmethane skeleton and a tetraarylsilane skeleton is The aryl groups are each 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 acridinyl skeleton, or the like. It is preferable that the compound contains either one of an amine skeleton and an azepine skeleton. The drive voltage of the child device can be reduced.

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

[0017] In the above configuration, 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 confinement effect of electronic devices. can.

[0018] In addition, another aspect of the present invention is a method for manufacturing a semiconductor device including a first layer, a second layer, and a second electrode between a first electrode and a second electrode. The first electrode has a third layer, and the first layer is disposed between the first electrode and the second 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 electron accepting properties, and the third material 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 structure, the first organic compound preferably has electron donating properties. By doing so, an electronic device with good carrier transport properties can be obtained.

[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 difference in refractive index between the layers can be suppressed. This can improve the light extraction efficiency and light confinement 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 confinement effect of electronic devices. can.

[0022] In the above structure, the volume ratio of the first substance in the first layer is With this configuration, it is preferable that the ratio is 0.01 or more and 0.3 or less. This can improve the light extraction efficiency and light confinement effect of the semiconductor laser.

[0023] In the above structure, the first substance may be titanium oxide, vanadium oxide, or tantalum oxide. oxides, molybdenum oxides, tungsten oxides, rhenium oxides, ruthenium oxides, chromium oxides It is preferred that the oxide contains any one of aluminum oxide, zirconium oxide, hafnium oxide, and silver oxide. By adopting this structure, an electronic device with good carrier transport properties can be obtained.

[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 one of cyano-naphthoquinodimethane (abbreviation: F6TCNNQ). With this structure, an electronic device with good carrier transport properties can be obtained.

[0025] In the above 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 a housing or a touch sensor. Another embodiment of the present invention is an electronic device having at least one 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. Furthermore, 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 light-emitting device in this specification includes an image display device. 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. is. [Effects 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 with 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-emitting efficiency can be provided. Alternatively, one aspect of the present invention provides a novel electronic device. Alternatively, an embodiment of the present invention provides an electronic device with a high optical trapping effect. Alternatively, one embodiment of the present invention can provide a novel semiconductor device. can.

[0028] The description of these effects does not preclude the existence of other effects. It is not necessary to have all of these effects. Effects other than these may be included in the description. It is obvious from the description of the specification, drawings, claims, etc. From this, it is possible to extract other effects. [Brief explanation of the drawings]

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

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

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

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

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

[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] The refractive index n is divided into two parts: n Ordinary, which is the refractive index for ordinary rays, and n Ordinary, which is the refractive index for extraordinary rays. There are two values, n Extraordinary, and n average, which is the average of both. In this specification, when simply referring to "refractive index," if anisotropy analysis is not performed, n If anisotropic analysis is performed, it can be read as n Ordinary. Also, anisotropy is the relationship between n Ordinary and n Extraordinary. It is expressed as the difference between the value of n Ordinary multiplied by two and the value of 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 transport 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 passing through the substrate 10 is incident on the electrode 11 and the The electrons pass through the carrier transport layer 30 and the organic semiconductor layer 20 from the electrode 11 side. When light that has entered the substrate 10 is absorbed by the functional layer 40, the light that has passed through the substrate 10 is absorbed by the electrode 11 and the capacitor. The light generated in the functional layer 40 passes through the rear transport layer 30. Alternatively, 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 less 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. For example, When light is generated in the functional layer 40, the light passes through or is reflected by the electrode 11. It is damped by the 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 made of a material having carrier acceptance or carrier donation properties. 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 has been difficult to obtain a layer with a low refractive index. When the donor substance is an organic compound, the organic compound may have a structure such as a cyclohexane skeleton. It is known that the refractive index decreases when a saturated cyclic compound is contained, but there is a problem with heat resistance. It was.

[0043] Here, the present inventors have discovered that by mixing 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 maintaining a carrier transport property. Furthermore, we found that it is possible to fabricate a layer with a low refractive index. 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 produced. The compound was also found to have 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, it is 1 or more and 1.73 or less, and more preferably 1.70 or less. Therefore, a good electronic device with reduced light attenuation can be obtained.

[0045] Either 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 1.70 or less. Thus, an electronic device can be obtained that has reduced light attenuation and good light extraction efficiency.

[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. 2. 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 has a substrate 200 and a substrate 210. The 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 hole injection layer 113. 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, electrode 101 is an anode, and 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. , the electrode 101 is a cathode, the electrode 102 is an anode, and the layers between the electrodes are stacked in the reverse order. That is, from the anode side, 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 injection 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 electrode 101 and the electrode 102 (cathode). 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), and at least the light-emitting layer 130, which includes a hole injection layer 111, a hole transport layer 112, an electron transport layer 118, and an electron injection layer The EL layer 100 may or may not have the layer 119. or reducing the electron injection barrier, improving hole or electron transportability, inhibiting the transport of the electrons, suppressing the quenching phenomenon caused by the electrodes, suppressing exciton diffusion, The functional layers may each have a function of: It may be a single layer or a laminate of multiple layers.

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

[0054] In order to efficiently obtain 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. 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 However, there is a method for increasing the thickness of the layers between the hole injection layer 111 and the hole transport layer 112. However, this configuration may cause problems such as an increase in the 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, it passes through the hole injection layer 111 and the hole transport layer 112. 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 of the film 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 having electron-donating properties is mixed with an organic compound having electron-accepting properties. Since many materials have a high refractive index, the refractive index of the hole injection layer 111 becomes high. It has been difficult to obtain a layer with a low refractive index while having hole injection properties. When the electron donating substance is an organic compound, the structure of the organic compound contains a cyclohexane skeleton. It is known that the refractive index decreases when saturated cyclic compounds such as cyclic compounds are included, but the heat resistance is also 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 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 properties 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 when a material having a low refractive index is used. Furthermore, it was found that the organic compound also 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, it 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 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 1.70 or less. Thus, a light emitting device 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, if a layer with a low refractive index is introduced in addition to the hole injection layer 111 and the hole transport layer 112, If this is the case, the number of layers to be fabricated increases, 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 prepared. Therefore, it is possible to use a 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 tetraarylsilane By using an organic compound having either one of the orchid skeletons and an electron-donating group, It is possible to fabricate a layer with a 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 can be combined with other light extraction enhancement techniques such as

[0065] Another embodiment of the present invention is to use 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 can be reduced. Since the hole injection characteristics can be improved while maintaining good light extraction efficiency, The organic compound having a tetraarylmethane skeleton can provide a light-emitting element with 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 the 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 difference in refractive index 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 desirable configuration when considering the output efficiency, but this configuration has the effect of carrier balance. The luminous efficiency of the light-emitting layer 130 may be reduced 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 light-emitting 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, that is, it is possible to suppress the guided mode. It is also possible to suppress the attenuation of light due to evanescent modes caused by reflection. 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. Therefore, good light extraction efficiency can be obtained.

[0070] In addition, the hole injection layer 111 contains an organic compound having electron donating properties and an organic compound having electron accepting properties. 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 properties is It is preferable that the volume ratio of the substance to the organic compound is 0.01 or more and 0.3 or less. 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 with a low refractive index as the material, a hole injection layer 111 with a low refractive index can be formed. The present inventors have found that it is possible to prepare

[0072] The attenuation of light due to the evanescent waves described above 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 can suppress the attenuation of light due to the incident wave, 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. It 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 with a low refractive index for the hole injection layer 111. The refractive index of a molecule is expressed by the Lorentz-Lorenz equation (Equation (1)) shown below.

[0075]

number

[0076] By transforming formula (1), formula (2) can be obtained.

[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 Avogadro's number, M is molecular weight, V0 is molar volume, and [R] is atomic refraction.

[0079] From equation (2), in order to reduce the refractive index n, it is sufficient to reduce φ, and from equation (1), To reduce φ, we need to reduce the atomic refraction [R]. In other words, we need to reduce the refractive index n. 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 that the atomic refraction [R] is small. Furthermore, it is preferable that the hole injection layer 111 has hole injection properties. Therefore, the organic compound used in the hole injection layer 111 further contains a compound having a structure in the molecule, such as an aromatic compound. It is more preferable that the organic compound has π-conjugation and electron-donating property. By doing so, 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 containing fluorine, such as a fluoro group or a trifluoromethyl group, or a cyclo Hexyl group and bonds via aromatic rings 3 The conjugation between aromatic rings, represented by hybrid orbitals, is broken. In addition, organic compounds with non-alternant hydrocarbons tend to have smaller 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 includes an aromatic amine skeleton, a pyrrole skeleton, a thiophene skeleton, and the like. Organic compounds with a methyl group, t-butyl group, or isopropyl group 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: Tetraarylmethane skeleton represented by formula (100), tetraarylmethane skeleton represented by general formula (101) Examples 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. In addition, it can be easily formed by vacuum deposition. Since it can easily form a thin film, it can be used suitably for 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 ring skeleton and a π-electron-rich heteroaromatic ring 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, The ring having a pyridine skeleton or an acridine skeleton may have a substituent. Examples of the alkyl group include alkyl groups having 1 to 6 carbon atoms and cycloalkyl groups having 3 to 6 carbon atoms. A group, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms may also 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. butyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, n-hexyl groups, etc. Also, cycloalkyl groups having 3 to 6 carbon atoms can be mentioned. Specific examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, and a cyclopentyl group. and cyclohexyl groups. 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 have two or more phenyl groups, the phenyl groups are bonded to each other to form a spirofluorene skeleton. In the case of unsubstituted hydroxyl groups, it is difficult to synthesize them and the cost of raw materials is low. It is advantageous.

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

[0089] Also, Ar 1 ~Ar 8 are each independently an aryl group having 6 to 13 carbon atoms or is an aromatic amine skeleton or a π-electron permeant represented by the above general formulas (200) to (220). The aryl group may have a substituent, and the substituents may be substituted with each other. 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 atom has two phenyl groups as substituents, and the phenyl groups are bonded together to form In this case, a spirofluorene skeleton is formed. 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 thereof include alkyl groups having 1 to 6 carbon atoms and cycloalkyl groups having 3 to 6 carbon atoms. Alternatively, an aryl group having 6 to 12 carbon atoms can be selected. Specific examples of alkyl groups having a prime number of 6 include methyl, ethyl, propyl, and propyl 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, for example: 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 systems, such as aryl groups with 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, functional groups with small π-conjugated systems such as alkenes Organic compounds are not suitable for electronic devices because they have poor carrier transport properties. An aryl group having 6 to 13 carbon atoms, particularly a phenyl group, which has carrier transport properties An organic compound with a small π-conjugated system is preferable as the organic compound used for 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 cycloalkyl groups having 3 to 6 carbon atoms include: Specifically, for example, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohex ... Examples of the aryl group having 6 to 13 carbon atoms include a hydroxyl group 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 12 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 bromine group, and the like. Examples of the alkyl group include butyl, isobutyl, tert-butyl, and n-hexyl groups. Specific examples of cycloalkyl groups having 3 to 6 carbon atoms include cycloalkyl groups such as: Examples include a propyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a naphthalene group, and a phenyl group. 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 compound having 6 to 10 carbon atoms. represents an arylene group of the number 13, and the arylene group may have a substituent, and the substituent is They may be bonded to each other to form a ring. Examples of such rings include the ring of a fluorenyl group. The carbon atom at position 9 has two phenyl groups as substituents, and the phenyl groups are bonded together to form a Therefore, a spirofluorene skeleton may be formed. Examples of the arylene group of 13 include a phenylene group, a naphthalenediyl group, and a biphenyl group. Specific examples include an arylene group, a fluorenediyl group, and the like. When the group has a substituent, the substituent is an alkyl group having 1 to 6 carbon atoms, a carbon atom, A cycloalkyl group having 3 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms is also preferred. Specific examples of alkyl groups having 1 to 6 carbon atoms include: , methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group 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 group, cyclohexyl group, etc. Examples of aryl groups with a prime number of 12 include phenyl, naphthyl, 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 applied. 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-ditriphenyl CzSi, 4,4,8,8,-12,12- Hexa-p-tolyl-4H-8H-12H-12C-aza-dibenzo[cd,mn]pi FATPA, 4,4'-bis(dibenzoazepin-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 are listed. The formula is shown below. The tetraarylmethane skeleton or the tetraarylsilane skeleton and The organic compounds having electron donating properties are not limited to these. The structural formulas of these compounds are shown below.

[0100] [ka]

[0101] Note that a low-molecular-weight organic compound can be suitably used in an 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 aspect of the present invention, by controlling the optical path length, it is possible to further The 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) obtained from the light emitting layer 130, 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). ) in the vicinity of the light-emitting layer 13. 0 indicates the recombination region of holes and electrons.

[0104] By performing such optical adjustment, the attenuation of light due to evanescent modes is reduced. Therefore, the light extraction efficiency 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 ( 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 This can reduce the attenuation of light due to the light emitting layer 130, thereby improving the light extraction efficiency from the light emitting layer 130. It is possible.

[0106] In order to perform the 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 improved from 130, but the fabrication process for light-emitting devices has also been simplified and A light emitting element having a driving voltage can be realized.

[0107] The attenuation of light due to the evanescent waves described above 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 an 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, but we will explain an example of applying this to a solar cell using Figure 1. A pair of light beams are 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 film thickness between the electrodes by adjusting the film thickness of the organic semiconductor layer 20 in FIG. With this configuration, the light incident on the electronic device 50 can be efficiently guided through the electronic device 50. Furthermore, in the electronic device according to one aspect of the present invention, This allows for suppression of light attenuation due to the incident wave, resulting in a more efficient light trapping effect. can be obtained.

[0109] <Material> Next, the 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 is 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 will be described later, the host material 131 is preferably a mixture of an organic compound 131_1 and an organic In the light-emitting layer 130, the host material 131 may contain a compound 131_2. The guest material 132 is dispersed in the host material 131. 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 the guest material of the light-emitting layer 130 (guest material 13 2) is preferably higher than the S1 level of the guest material 132. In this case, the host material 131 (organic compound 131_1 and organic compound 131_2) of the light-emitting layer 130 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 preferable.

[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 transporting property) is preferably used. A material with electron transport properties (1×10 -6 cm 2 / Vs or higher electron mobility It is preferable that the material be a material that can be used in the present invention.

[0112] Specifically, for example, 4,6-bis[3-(phenanthrene-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) 4,6-diphenyl-2,3-dihydro-2,4 ... Phenyl-1,3,5-triazine (abbreviation: mBnfBPTzn), 2,4,6-tris( Biphenyl-3-yl)-1,3,5-triazine (abbreviation: T2T), 2,4,6-tri Bis[3'-(pyridin-3-yl)-biphenyl-3-yl]-1,3,5-triazine (Abbreviation: TmPPPyTz), 9-[4-(3,5-diphenyl-1H-1,2,4-thiazolinone] 9H-carbazole (abbreviation: CzTAZ(1H)) Heterocyclic compounds having a triazine skeleton, a pyrimidine skeleton, or a triazole skeleton such as Moreover, heterocyclic compounds having such a skeleton have electron transport properties. The materials mentioned here have a high conductivity of 1×10 -6 cm 2 / V It is a substance that has an electron mobility of 1000 s or more. It is a substance that has a higher electron transporting property than a hole transporting property. If necessary, 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 thiazolinone derivatives and purine derivatives can also be used. The thing is 1 x 10 -6 cm 2 It is preferable that the material has an electron mobility of 1 / Vs or more.

[0114] Specifically, for example, bathophenanthroline (abbreviated as BPhen), bathocuproine ( Heterocyclic compounds with a pyridine skeleton, such as 2-[3-(dibenzothiophene) phen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 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 (9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq- III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h] Quinoxaline (abbreviation: 7mDBTPDBq-II) and 6-[3-(dibenzothiophene) (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), etc. Heteroaromatic 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 compound has a nitrogen-containing heterocyclic five-membered skeleton. For example, an imidazole skeleton Examples include the triazole skeleton and the tetrazole skeleton. As 2, a material having a higher hole transporting property than electron transporting property (hole transporting material) can be used. , 1×10 -6 cm 2 It is preferable that the material has a hole mobility of .gtoreq.Vs. 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)trimethylol Tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(di benzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole ( Abbreviated as 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 suitably used. Examples include indole derivatives, carbazole derivatives, triarylamine skeletons, etc. 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) can be used, and the -6 cm 2 / Vs It is preferable that the hole transport material is a polymer having a hole mobility of at least 1000 .mu.m. It may also be a compound.

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

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

[0121] Also, N,N-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl] ]-9H-carbazol-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] Phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), N,9-diphenyl -N-{4-[4-(10-phenyl-9-anthryl)phenyl]phenyl}-9H- Carbazol-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-(9-anthryl)phenyl]-9H-carbazole (abbreviation: DPCzPA), 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-vinyltriphenyl ether) Nylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenyl amino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide]( abbreviation: PTPDMA), poly[N,N'-bis(4-butylphenyl)-N,N'-bis Polymer compounds such as [(phenyl)benzidine] (abbreviation: Poly-TPD) can also be used. can.

[0123] Furthermore, examples of materials with high hole transport properties include 4,4'-bis[N-(1-naphthyl)-2-methyl-2-propanol]. N,N'-(phenyl)-N-phenylamino]biphenyl (abbreviation: NPB or α-NPD) Bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4, 4'-diamine (abbreviation: TPD), 4,4',4''-tris(carbazol-9-yl) ) triphenylamine (abbreviation: TCTA), 4,4',4''-tris[N-(1-naphthyl) 4,4-Triphenylamine (abbreviation: 1'-TNATA) ',4''-Tris(N,N-diphenylamino)triphenylamine (abbreviation: TDAT A), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino] Triphenylamine (abbreviation: MTDATA), 4,4'-bis[N-(spiro-9,9' -bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4 -phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenyl Nylamine (abbreviation: mBPAFLP), N-(9,9-dimethyl-9H-fluorene-2 -yl)-N-{9,9-dimethyl-2-[N'-phenyl-N'-(9,9-dimethyl -9H-fluoren-2-yl)amino]-9H-fluoren-7-yl}phenylamino N-(9,9-dimethyl-2-diphenylamino-9H- Fluoren-7-yl)diphenylamine (abbreviation: DPNF), 2-[N-(4-diphenyl) N-phenylaminophenyl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: DPASF), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl) Triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9- Phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1B) P), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl) Triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''- (9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCBN BB), 4-phenyldiphenyl-(9-phenyl-9H-carbazol-3-yl)a amine (abbreviation: PCA1BP), N,N'-bis(9-phenylcarbazol-3-yl) -N,N'-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N,N', N''-triphenyl-N,N',N''-tris(9-phenylcarbazole-3-yl) N-(4-biphenyl)benzene-1,3,5-triamine (abbreviation: PCA3B) -N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-chlor PCBiF, N-(1,1'-biphenyl-4-yl) -N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-di Methyl-9H-fluoren-2-amine (abbreviation: PCBBiF), 9,9-dimethyl-N -phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl] Fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl -9H-carbazol-3-yl)phenyl]spiro-9,9'-bifluorene-2-a PCBASF, 2-[N-(9-phenylcarbazol-3-yl)-N -phenylamino]spiro-9,9'-bifluorene (abbreviation: PCASF), 2,7-bi Spiro-9,9'-[N-(4-diphenylaminophenyl)-N-phenylamino]spiro Bifluorene (abbreviation: DPA2SF), N-[4-(9H-carbazol-9-yl)fluorene] N,N'-phenyl]-N-(4-phenyl)phenylaniline (abbreviation: YGA1BP), Bis[4-(carbazol-9-yl)phenyl]-N,N'-diphenyl-9,9-di Aromatic amine compounds such as methylfluorene-2,7-diamine (abbreviation: YGA2F) Also, 3-[4-(1-naphthyl)-phenyl]-9-phenyl can be used. -9H-carbazole (abbreviation: PCPN), 3-[4-(9-phenanthryl)-phenyl 3,3'-bis(9- phenyl-9H-carbazole) (abbreviation: PCCP), 1,3-bis(N-carbazolyl ) benzene (abbreviation: mCP), 3,6-bis(3,5-diphenylphenyl)-9-phenyl 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 benzothiazolinone (Cz2DBT), Among the compounds mentioned above, those having a pyrrole skeleton, an aromatic Compounds having an aromatic amine skeleton are preferred because they are stable and highly reliable. The compound having the formula (I) has high hole transporting properties and contributes to reducing the driving voltage.

[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, Marine derivatives, phenoxazine derivatives, phenothiazine derivatives, etc. are preferred, and examples thereof include the following: 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 (9-phenyl)pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn) , N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H -fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMem FLPAPrn), N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl )phenyl]-N,N'-bis(4-tert-butylphenyl)pyrene-1,6-diazo amine (abbreviation: 1,6tBu-FLPAPrn), N,N'-diphenyl-N,N'-bis [4-(9-phenyl-9H-fluoren-9-yl)phenyl]-3,8-dicyclohexyl Xylpyrene-1,6-diamine (abbreviation: ch-1,6FLPAPrn), N,N'-biphenyl bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbe 4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl) -4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA) , 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-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) (9H-carbazol-9-yl)phenyl)-N-[4-(9H-carbazol-9-yl)phenyl]-N- Phenylanthracene-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenyl Dianthracen-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-[(2,3-dimethyl- ... ,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 iridium, rhodium, or platinum-based Organometallic complexes or metal complexes are mentioned, among which organic iridium complexes, e.g., iridium The orthometalated ammonium complex is preferred. The orthometalated ligand is 4H-triazolium. 1H-triazole ligands, 1H-triazole ligands, imidazole ligands, pyridine ligands, pyrimidine ligands Examples of the metal complexes include quinazine, pyrazine, and isoquinoline ligands. 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-trimethyl- Triazolato)iridium(III) (abbreviation: Ir(Mptz)3), tris[4-(3- Biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]i Iridium(III) (abbreviation: Ir(iPrptz-3b)3), tris[3-(5-biphenyl] (phenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]irid Ir(III) (abbreviated as Ir(iPr5btz)3), a 4H-triazole skeleton and organometallic iridium complexes with tris[3-methyl-1-(2-methylphenyl) -5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: Ir (Mptz1-mp)3), tris(1-methyl-5-phenyl-3-propyl-1H- 1,2,4-Triazolate)iridium(III) (abbreviation: Ir(Prtz1-Me) 3) and fac-triazole-based organometallic iridium complexes. S[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole] 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) Organometallic iridium complexes with various imidazole structures and bis[2-(4',6'-difluoromethyl)-2-(4-phenyl ... (fluorophenyl)pyridinato-N,C 2’ ]iridium(III) tetrakis(1-pyra 2-(4',6'-difluorophenyl) bis[2-(4',6'-difluorophenyl) benzoate (abbreviation: FIr6) Pyridinato-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) Electron-withdrawing groups such as acetylacetonate (abbreviation: FIr(acac)) Organometallic iridium complexes having phenylpyridine derivatives as ligands are also included. Among them, 4H-triazole skeleton, 1H-triazole skeleton and imidazole skeleton Organometallic iridium complexes with such nitrogen-containing five-membered heterocyclic skeletons have high triplet excitation energies. It is particularly preferred because it has a high energy density, is highly reliable, and has excellent luminous efficiency.

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

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

[0130] The light-emitting material contained in the light-emitting layer 130 is a material capable of converting triplet excitation energy into light. The material capable of converting triplet excitation energy into luminescence is preferably a phosphorescent material. In addition to the thermally activated delayed fluorescence compounds, Therefore, phosphorescence The term "thermally activated delayed fluorescent compound" may be read as "thermally activated delayed fluorescent material." A thermally activated delayed fluorescent material is a material that has a triplet excitation energy level and a singlet excitation energy level. The difference between the triplet and singlet excited states is small, and reverse intersystem crossing allows the energy to be transferred from the triplet excited state to the singlet excited state. Therefore, the triplet excited state can be converted into a small amount of thermal energy. Therefore, upconversion (reverse intersystem crossing) from the singlet excited state is possible. Furthermore, 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, more preferably greater than 0 eV and not greater than 0 The most notable features are that the energy density is less than 0.1 eV.

[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. It 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]carbazole-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol {4,6-diphenyl-1,3,5-triazine (PC CzPTzn), 2-[4-(10H-phenoxazin-10-yl)phenyl]-4, 6-Diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5- Phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl PPZ-3TPT, 3-(9,9-dimethyl- 9H-Acridine-10-yl)-9H-xanthen-9-one (Abbreviation: ACRXTN) , bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10'H-spiro[acridine -9,9'-anthracene]-10'-one (abbreviation: ACRSA), etc. The heterocyclic compounds have a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring, Among them, a skeleton having a π-electron-deficient heteroaromatic ring is preferred. Among them, diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton) or triazine skeleton The azine skeleton is preferred because it is stable and reliable. Among the skeletons that have such structures, acridine skeleton, phenoxazine skeleton, thiophene skeleton, and furan skeleton are Since the pyrrole skeleton and the pyrrole skeleton are stable and reliable, any of the skeletons can be used. It is preferable that the pyrrole skeleton has one or more of the following. skeleton, a carbazole skeleton, and 3-(9-phenyl-9H-carbazol-3-yl)- A 9H-carbazole skeleton is particularly preferred. The materials in which the π-electron-rich heteroaromatic ring is directly bonded to the π-electron-deficient heteroaromatic ring exhibit the donor property of the π-electron-rich 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 preferable because 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 may have.

[0135] The material that can be used for the light-emitting layer 130 is not particularly limited, but examples thereof include anthracene, Helical derivatives, phenanthrene derivatives, pyrene derivatives, chrysene derivatives, dibenzo[g, p] chrysene derivatives and other condensed polycyclic aromatic compounds, specifically 9,10-diphenyl 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-mentioned Singlet excited energy level 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, for example, 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 4,4-Hexadiazol-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, oxalyl ligands, Examples of such metal complexes include those having a thiazole ligand or a thiazole ligand. For example, tris(8-quinolinolato)aluminum(III) (abbreviation: Alq), tris(8-quinolinolato)aluminum(III) Bis(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq3), Bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq2 ), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum ( III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq) and 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 composed of two or more layers. When the light-emitting layer 130 is formed by laminating the first light-emitting layer and the second light-emitting layer in this order from the hole transport layer side, a substance having hole transport properties is used as a host material for the first light-emitting layer, and a substance having hole transport properties is used as a host material for the second light-emitting layer In addition, a structure in which a substance having an electron transporting property is used as the first light-emitting layer and the second light-emitting layer is also available. The light-emitting materials in the optical layer and the optical layer may be the same or different materials, and they may emit light of the same color. Even if the material has a function of emitting light, it may have a function of emitting light of different colors. The two light-emitting layers may contain light-emitting materials that emit light of different colors. By using each of these layers, multiple light emissions can be obtained simultaneously. It is preferable to select a light-emitting material for each light-emitting layer so that the resulting light emitted will be white.

[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 rabbet printing. In addition to the above-mentioned materials, quantum dots and the like can also be used. Even if the inorganic compound or polymer compound (oligomer, dendrimer, polymer, etc.) good.

[0140] <Hole injection layer> The hole injection layer 111 is formed by injecting holes from one of the pair of electrodes (electrode 101 or electrode 102). It has the function of promoting hole injection by reducing the injection barrier, and has, for example, electron-accepting properties Formed from transition metal oxides, phthalocyanine derivatives, aromatic amines, heteropolyacids, etc. Examples of 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 oxides of zirconium, hafnium, and silver. The oxide has excellent electron-accepting properties and can be easily formed into a film by vacuum deposition or wet method. As the phthalocyanine derivative, phthalocyanine and metal phthalocyanine are preferred. 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(styrene sulfonic 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 a material having a low refractive index and a hole transporting property, such as that described above, and an electron transporting property, such as that described above. It is preferable to use a layer having a composite material of materials that exhibit receptivity. By doing so, it is possible to form a layer that has hole injection and transport properties and also has a low refractive index. As the organic material having the resistance, 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 under the presence of an electric field. The organic materials that exhibit electron-accepting properties are 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 containing electron-withdrawing groups (halogen groups or cyano groups) such as phenylene (abbreviation: HAT-CN) Also, transition metals such as titanium, vanadium, tantalum, molybdenum, ruthenium, rhenium, ruthenium, chromium, zirconium, hafnium, silver, etc. with oxygen Specifically, titanium oxide, vanadium oxide, tantalum oxide, etc. 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 transport 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 those with a bond, and those with bulky substituents An organic compound having an aromatic ring having such a structure in which the conjugation between aromatic rings is broken can be preferably used. Examples of the skeleton having such a structure include the above-mentioned tetraarylmethane skeleton and tetraarylsilane skeleton. However, 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. The substance itself is highly effective in increasing hole injection properties, but has the problem of a high refractive index. However, the above-mentioned transition metal and oxygen-containing materials are used as electron-accepting materials. 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 also ensuring hole injection and transport properties. In other words, this configuration cancels out the disadvantages of both and only shows the advantages. This is because the electron-accepting properties of materials containing transition metal oxides are high, and even a small amount of addition can inject holes. This is thought to be due to the fact that it allows for security.

[0143] As the hole transporting material, a material having a higher hole transporting property than an electron transporting property can be used. x10 -6 cm 2 It is preferable that the material has a hole mobility of .gtoreq. / Vs. 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 hole transport materials that can be used in the light-emitting layer 130 are It is possible to use carbazole derivatives, aromatic hydrocarbons, stilbene derivatives, etc. However, it is particularly preferred that the compound 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)-9,9'-bianthryl, (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]fluoren phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), 4,4',4''-(benzyl) (benzophenone-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)fluorene phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl [(9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation :DBTFLP-IV), 4-[3-(triphenylen-2-yl)phenyl]dibenzo Thiophene compounds such as thiophene (abbreviation: mDBTPTp-II), furan compounds, Examples of compounds that can be used include olefin compounds, triphenylene compounds, and phenanthrene compounds. Among the compounds mentioned above, those with pyrrole skeleton, furan skeleton, thiophene skeleton, and aromatic amine skeleton are Compounds having such a skeleton are preferred because they are stable and reliable. The material has a high hole transporting property and also contributes to reducing the driving voltage.

[0147] <Hole transport layer> The hole transport layer 112 is a layer containing a hole transport material. The hole transporting layer 112 can be formed by the hole injection layer 111. 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 that the HOMO level is 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 1 / Vs or more. However, other substances may be used as long as they have a higher hole transporting property than electron transporting property. The layer containing a substance with a high hole transporting property may be a single layer or a double layer of the above substance. More than one layer may be stacked.

[0149] ≪Electron transport layer≫ The electron transport layer 118 is connected to the other of the pair of electrodes (electrode 101 or electrode 102) via the electron injection layer 119. The electron transport material has the function of transporting electrons injected from the electrode 102 to the light-emitting layer 130. As the material, a material with higher electron transportability than holes can be used, and the -6 cm 2 It is preferable that the material has an electron mobility of 1 / Vs or more. As materials (materials with electron transport properties), π-electron deficient materials such as nitrogen-containing heteroaromatic compounds are Heteroaromatics and metal complexes can be used. The pyridine derivatives, bipyridine derivatives, and pyrimidine derivatives listed as electron transport materials that can Derivatives, triazine derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, phenazine Intramolecular derivatives, triazole derivatives, benzimidazole derivatives, oxadiazole derivatives, which have a heteroaromatic skeleton containing two or more nitrogen atoms and 1 to 20 carbon 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 1 / Vs or more. It is preferable that a substance other than the above-mentioned substances has a higher electron transporting property than a 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] Further, metal complexes having heterocycles are also exemplified, for example, quinoline ligands, benzoquinoline Metal complexes with oxazole, thiazole, or thiazole ligands are also suitable. Specifically, for example, tris(8-quinolinolato)aluminum(III) (abbreviation: A lq), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Al mq3), bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation :BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)a Aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Metal complexes having a quinoline skeleton or a benzoquinoline skeleton, such as Znq, In addition, bis[2-(2-benzoxazolyl)phenolato]zinc(II)( Abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phenolato]zinc(II) ( Metal complexes with oxazole or thiazole ligands, such as ZnBTZ 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 method of adding a material with high electron transporting properties to a material with high electron trapping properties. A layer containing a small amount of Such a configuration allows the electron transporting property of the electron transporting material to be properly 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., shortened device life). It is highly effective in suppressing the following:

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

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

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

[0155] ≪Quantum dots≫ Quantum dots are semiconductor nanocrystals with a size of several nanometers to several tens of nanometers, and are 1×10 3 Individual to 1×10 6 Quantum dots are composed of about 100 atoms. Therefore, even if quantum dots are made of the same material, the emission wavelengths vary 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 peak width in the emission spectrum, which allows for emission of light with good color purity. Furthermore, the theoretical internal quantum efficiency of quantum dots is said to be nearly 100%. This is significantly more than 25% of organic compounds that exhibit fluorescence, and 25% of organic compounds that exhibit phosphorescence. This means that quantum dots can be used as light-emitting materials. This allows for the production of light-emitting devices with high luminous efficiency. Since the inherent 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 complexes. 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 elements and Group 17 elements, compounds of Group 14 elements and Group 15 elements, Compounds of group 11 elements and group 17 elements, iron oxides, titanium oxides, chalcogenide spines Examples of suitable materials include semiconductor clusters.

[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, 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 Sulfur dioxide, 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 vanadium oxide, tungsten oxide, tantalum oxide, titanium oxide, zirconium 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 thereof. In addition, alloy quantum dots, whose compositions are expressed in any ratio, may be used. For example, alloy quantum dots of cadmium, selenium, and sulfur can be obtained 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 possible to cover the core with another inorganic compound with a wider band gap. By forming a shell of material, defects and dangling bonds on the nanocrystal surface can be eliminated. This significantly 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 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 can prevent aggregation and increase solubility in solvents. It can also reduce reactivity and improve electrical conductivity. It is also possible to improve stability. Examples of protecting agents (or protecting groups) include polio Polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene Polyoxyethylene alkyl ethers such as ethylene oleyl ether, tripropyl phosphite phosphine, tributylphosphine, trihexylphosphine, trioctylphosphine, etc. Trialkylphosphines, polyoxyethylene n-octylphenyl ether, polyoxyethylene Polyoxyethylene alkylphenyl ethers such as oxyethylene n-nonylphenyl ether esters, 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 nitrogen-containing aromatic compounds such as pyridine, lutidine, collidine, and quinolines , hexylamine, octylamine, decylamine, dodecylamine, tetradecylamine aminoalkanes such as dibutylsulfone, 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, palmitoyl 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 terephthalate Examples include amines.

[0161] As quantum dots become smaller, their band gaps become larger, so they can emit the desired wavelengths. The size of the crystal is adjusted accordingly to obtain long-range light. As a result, the emission of quantum dots shifts 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 size (diameter) of quantum dots can be adjusted over a range of wavelengths. The range of 0.5 nm to 20 nm, preferably 1 nm to 10 nm, is usually used. The narrower the size distribution of quantum dots, the narrower the emission spectrum. The quantum dots can be formed in any shape, and can have excellent color purity. The quantum dots may be spherical, rod-shaped, disc-shaped, or have other shapes. Since the rods have the function of emitting directional light, quantum rods can be used as light-emitting materials. This makes it possible to obtain a light emitting device with 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 more than just a light-emitting material; it also has a high luminous efficiency. 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 A host material with a high level and excellent 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, in this respect, it is a preferable light-emitting element from the viewpoint of life span. 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 However, it is preferable to form the light-emitting layer only from quantum dots. When forming a light-emitting layer in which the quantum dots are dispersed in a host as a light-emitting material, the host material Alternatively, the host material and the quantum dots are dissolved or dispersed in a suitable liquid medium. Disperse and apply wet processes (spin coating, casting, die coating, blade coating) 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 ion beam splitting method or 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, and the like. Ketones such as xanone, fatty acid esters such as ethyl acetate, halogens such as dichlorobenzene aromatic hydrocarbons, toluene, xylene, mesitylene, cyclohexylbenzene, etc. Hydrocarbons, aliphatic hydrocarbons such as cyclohexane, decalin, and dodecane, dimethylformamide Organic solvents such as dimethyl amide (DMF) and dimethyl sulfoxide (DMSO) can be used. Cut.

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

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

[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 formed of a conductive material having a permeability function. The transmittance of visible light is 40% or more and 100% or less, preferably 60% or more and 100% or less, or The resistivity is 1×10 -2 Examples include conductive materials with a resistance of Ω·cm or less.

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

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

[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. Any material that has the function of providing the desired electrical conductivity may be used. For example, in addition to the oxide conductors described above, oxide semiconductors and organic materials can be used. The organic material may be, for example, a light-emitting layer, a hole injection layer, a hole transport layer, an electron transport layer, or an electron transport layer. The materials exemplified for the electron injection layer are also usable. Inorganic carbon materials and metals that are light-transmitting are also usable. A thin film can also be used, and multiple layers of several nanometers to several tens of nanometers may be stacked.

[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, materials in Group 1 or 2 of the Periodic Table of Elements. Elements belonging to the group (alkali metals such as lithium, sodium, and cesium, calcium, strontium, etc.) Alkaline earth metals such as rontium, magnesium, etc.), alloys containing these elements (e.g., Rare earth metals such as Ag and Mg, Al and Li), europium (Eu), Yb, etc. An alloy containing a metal, such as an alloy containing aluminum or silver, can be used.

[0173] Furthermore, when the electrode 101 or the electrode 102 is used as an anode, a material having a large work function (4. It is preferable to use a material having a refractive index of 0 eV or more.

[0174] The electrodes 101 and 102 are made of a conductive material that reflects light and a light-transmitting material. In this case, the electrode 101 and the electrode 102 may be laminated with a conductive material having a permeability function. O2 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 the function of adjusting the optical distance so that the optical path can be adjusted.

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

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

[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. Alternatively, a flexible substrate may be used. The substrate is a flexible substrate, such as polycarbonate. Examples of suitable substrates include plastic substrates made of vinyl acetate and polyarylate. Inorganic vapor deposition films can also be used. Any other material may be used as long as it functions as a support in the development. Anything that has the function of protecting the optical element and the optical device may be used.

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

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

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

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

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

[0184] As described above, 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 The light emitting mechanism of the light emitting element will be described below with reference to FIGS. 3 and 4, the parts having the same functions as those shown in FIG. 2(A) are denoted by the same reference numerals. In some cases, the hatch pattern is used and the symbols are omitted. Also, parts with similar functions are indicated by The same reference numerals are used and detailed descriptions thereof may be omitted.

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

[0187] The light-emitting element 250 shown in FIG. 3A has a pair of electrodes (electrodes 101 and 102) between them. , a plurality of light-emitting units (in FIG. 3A, light-emitting unit 106 and light-emitting unit 1 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 addition, in the light-emitting element 250 shown in FIG. 3(A), the light-emitting unit 106 and the light-emitting unit 108 are stacked, and a charge is generated 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 has 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 layer 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 It has 9.

[0190] The charge generation layer 115 is formed by adding an acceptor material, which is an electron acceptor, to a hole transport material. Even if the electron transport material is an electron donor, a donor material may be added to the electron transport material. Alternatively, both of these structures may be stacked.

[0191] When the charge generation layer 115 contains a composite material of an organic compound and an acceptor substance, the The composite material that can be used for the hole-injection layer 111 shown in Embodiment 1 is used as the composite material. The organic compounds include aromatic amine compounds, carbazole compounds, aromatic carbonized compounds, and the like. Various compounds such as hydrogen and polymer compounds (oligomers, dendrimers, polymers, etc.) are used. As for organic compounds, those with a hole mobility of 1×10 -6 cm 2 / Vs However, 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 carrier transport properties, allowing for low voltage and low current operation. In addition, the anode side of the light-emitting unit is in contact with the charge generating layer 115. In this case, the charge generation 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 generation 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 generation layer 115 may be a layer containing a composite material of an organic compound and an acceptor substance, or another layer containing a compound of an organic compound and an acceptor substance. For example, the organic EL element may be formed as a laminated structure in which layers made of the organic EL element are combined. A layer including a composite material of a compound and an acceptor substance and a layer including a compound selected from electron donor substances. The compound may be formed by combining a layer containing the compound with a compound having a high electron transporting property. A layer containing a composite material of an organic compound and an acceptor substance and a layer containing a transparent conductive film are combined. It may be formed by combining the above.

[0193] The charge generating layer 115 sandwiched between the light emitting unit 106 and the light emitting unit 108 When a voltage is applied between the electrode 101 and the electrode 102, electrons are injected into one of the light-emitting units, It is sufficient if the hole is injected into the other light-emitting unit. For example, in FIG. 3(A), When a voltage is applied so that the potential of electrode 101 is higher than the potential of electrode 102, The charge generating layer 115 injects electrons into the light-emitting unit 106 and holes into the light-emitting unit 108. Enter.

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

[0195] By forming the charge generating layer 115 using the above-mentioned materials, when a light emitting layer is laminated, In this case, the increase in the driving voltage can be suppressed.

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

[0197] In each of the above configurations, the light emitting units 106 and 108 are 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 emitting luminance with a small current value, which is preferable. It is also preferable that the light emitting units 106 and 108 emit light of different colors. When the light-emitting element 250 has a guest material having the function of emitting light in multiple colors, the light-emitting element 250 emits light in multiple colors. In this case, either one or both of the light-emitting layer 120 and the light-emitting layer 170 By using a plurality of light-emitting materials with different emission wavelengths, the light emitted by the light-emitting element 250 The spectrum is composed 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 emitted. The guest material is selected to produce a high white emission, or an emission having at least red, green, and blue colors. It is preferable to select a

[0199] In addition, in the case of a light-emitting element in which three or more light-emitting units are stacked, the The guest materials may emit light of the same color or different colors. In the case where a plurality of light-emitting units are included, the emitted colors of the light emitted by the plurality of light-emitting units are Compared to other colors, high luminance can be obtained 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 light-emitting units having fluorescent materials of the same color are used, and one light-emitting unit having a different luminescent color from the fluorescent material 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 phosphorescent light-emitting unit, blue It contains two light-emitting units containing color fluorescent materials and one light-emitting unit containing yellow phosphorescent material. Two layers of light-emitting elements or light-emitting units containing blue fluorescent material and two layers of red phosphorescent material and green phosphorescent material a light-emitting device having one light-emitting layer unit containing a blue fluorescent material, two light-emitting layers containing a red fluorescent material, and 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 emitted efficiently.

[0201] In addition, at least one of the light-emitting layer 120 and the light-emitting layer 170 is further divided into layers, Each divided layer 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 hole transport properties is used as the host material of the first light-emitting layer, and a material having hole transport properties 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 contained in the light-emitting layer and the second light-emitting layer may be the same material or different materials. 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 the 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 that is composed of three primary colors or four or more luminescent 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] Furthermore, the light-emitting layer 120 of the light-emitting unit 108 is formed by adding a guest The guest material 121 is a fluorescent material. , as explained below.

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

[0205] The charge injected from the pair of electrodes (electrode 101 and electrode 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 large amounts compared to the material 121, the generation of excitons The excited state of the host material 122 is formed. ) pair.

[0206] When the excited state of the formed host material 122 is a singlet excited state, the host material 12 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, the singlet excited state in the guest material 121 is Once formed, the guest material 121 quickly emits light. For this purpose, it is preferable that the guest material 121 has a high fluorescence quantum yield. In 1, the same applies when carriers recombine and the resulting excited state is a singlet excited state. is.

[0208] Next, when carrier recombination forms a triplet excited state of the host material 122, 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: The T1 level of the host material 122 is lower than the T1 level of the guest material 121. 3C shows this case, but the T1 level of the host material 122 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) Triplets generated by carrier recombination are generated by Excitons interact with each other, transferring excitation energy and exchanging spin angular momentum. As a result, the S1 level (S FH ) has an energy of 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 FH from a lower energy guest material121 S1 level (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] 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] Furthermore, 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 Figure 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 light into energy. 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 the guest material 121, and the guest material 121 is transferred to the guest material 121, thereby producing fluorescence. 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 preferable.

[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 It is preferable that the weight ratio of the guest material 121 is low. When the guest material 121 is added, the weight ratio of the guest material 121 is preferably greater than 0 and equal to or less than 0.05. By doing so, the probability of carrier recombination in the guest material 121 can be reduced. In addition, the T level (T FH ) to the T1 level (T FG ) This can reduce the probability of energy transfer to

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

[0217] <Configuration example 2 of light-emitting element> 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 (in FIG. 4(A), light-emitting elements) are disposed between the electrodes 101 and 102. The light unit 106 and the light-emitting unit 110 are included. At least one light-emitting unit 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. 4(A), the light-emitting unit 106 and the light-emitting unit The light-emitting unit 106 and the light-emitting unit 110 are stacked together, 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 in the light-emitting unit 106. It's nice.

[0220] The light emitting element 252 also 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 layer The light-emitting unit 110 also includes a light-emitting layer 140. In addition to the above, a hole injection layer 116, a hole transport layer 117, an electron transport layer 118, and an electron injection layer 11 It has 9.

[0221] At least one of the multiple units has the same configuration as that shown in the first embodiment. By applying this configuration, a light-emitting device with 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 the guest material 141 and the organic compound 142_2. The following description will be given assuming that 1 is a phosphorescent material.

[0223] <Light Emitting Mechanism of 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 contained 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 is acceptable as long as one of the compounds has a hole transporting property. It is more preferable that the other is a compound having electron transport properties.

[0226] The organic compound 142_1, the organic compound 142_2, and the guest material in the light-emitting layer 140 The correlation of the energy level with 141 is shown in Figure 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 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] One of the organic compounds 142_1 and 142_2 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 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 formation of an excited state in the host material 142. The driving voltage of the element can be reduced.

[0230] And the S of the exciplex PE and T PE The energy of both the guest material 141 (phosphorescent material) The electrons are then transferred to the T1 level of the corresponding cation (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 to the S1 level (S PE ) and T1 level (T PE )mosquito The T1 level (T PG ) can transfer energy to

[0232] In addition, 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 T1 levels (T PH1 and T PH2 ) or It is preferable that the organic compound 142_1 and the organic compound 142_2 are smaller than the organic compound 142_1. Compound 142_2) is less likely to quench the triplet excitation energy of the exciplex. Energy transfer from the exciplex to the guest material 141 occurs efficiently.

[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 is higher than the other, and the LUMO level of one 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 hole transporting properties and organic compound 142_1 has electron transporting properties, organic compound 1 The HOMO level of 42_2 is preferably 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_2 are 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, it is 0.05 eV or more, more preferably 0.1 eV or more, and even more preferably Preferably, it is 0.2 eV or more.

[0234] In addition, the combination of organic compound 142_1 and organic compound 142_2 has hole transport properties. When a compound having electron transport properties is used in combination with a compound having electron transport properties, the mixing ratio Specifically, the carrier balance can be easily controlled by using a material having hole transport properties. The weight ratio of the compound having electron transport properties to the compound having electron transport properties 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] The above-described routes E3 to E5 are referred to as ExTET (Ex It is sometimes called plex-triplet energy transfer. In other words, the light-emitting layer 140 transfers the excitation energy from the exciplex to the guest material 141. In this case, it is not necessarily T PE From S PE High efficiency of reverse intersystem crossing is required No, S PE The quantum yield of light emission from the material does not need to be high, so a wide range of materials can be selected. It becomes possible.

[0237] Furthermore, the light emitted from the light-emitting layer 170 has a peak at a shorter wavelength than the light emitted from the light-emitting layer 140. It is preferable that the light-emitting element has a structure including a phosphorescent material that emits light of a short wavelength. Therefore, by using fluorescent light for short wavelengths, A light-emitting element with little deterioration in luminance can be provided.

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

[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 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 122 is higher than the S1 level of the fluorescent material 121. It is preferable that the T1 level is lower than the T1 level of the source 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 compounds shown in the first embodiment are 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), metal complexes such as 2-(4-biphenylyl)-5-(4-tert- butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5 -(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene OXD-7, 3-(4-biphenylyl)-4-phenyl-5-(4-te rt-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 2,2',2' '-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazoline) TPBI), bathophenanthroline (BPhen), bathocuproline BCP, 9-[4-(5-phenyl-1,3,4-oxadiazole-2- Heterocyclic compounds such as 4,4-phenyl-9H-carbazole (abbreviation: CO11), '-Bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as NPB) is α-NPD), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1 ,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4'-bis[N-( spiro-9,9'-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation Aromatic amine compounds such as benzophenone (BSPB) are also suitable. Nanthrene derivatives, pyrene derivatives, chrysene derivatives, dibenzo[g,p]chrysene derivatives Condensed polycyclic aromatic compounds such as 9,10-diphenylanthracene are specifically exemplified. (abbreviation: DPAnth), N,N-diphenyl-9-[4-(10-phenyl-9-anthracene] tolyl)phenyl]-9H-carbazol-3-amine (abbreviation: CzA1PA), 4-( 10-phenyl-9-anthryl)triphenylamine (abbreviation: DPhPA), 4-(9 H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)tripheny YGAPA, N,9-diphenyl-N-[4-(10-phenyl-9 -anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), N ,9-diphenyl-N-{4-[4-(10-phenyl-9-anthryl)phenyl]phenyl {phenyl}-9H-carbazol-3-amine (abbreviation: PCAPBA), N,9-diphenyl N-(9,10-diphenyl-2-anthryl)-9H-carbazol-3-amine (abbreviation: 2PCAPA), 6,12-dimethoxy-5,11-diphenylchrysene, N, N,N',N',N'',N'',N''',N'''-octaphenyldibenzo[g, p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), 9-[4-(1 0-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: CzPA), 3,6-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H -carbazole (abbreviation: DPCzPA), 9,10-bis(3,5-diphenylphenyl) ) anthracene (abbreviation: DPPA), 9,10-di(2-naphthyl)anthracene (abbreviation: :DNA), 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation :t-BuDNA), 9,9'-bianthryl (abbreviation: BANT), 9,9'-(styryl) 9,9'-(stilbene-3,3'-diyl)diphenanthrene (abbreviation: DPNS), 3,3',3''-(phenyl-4,4'-diyl)diphenanthrene (abbreviation: DPNS2), Benzene-1,3,5-triyl)tripylene (abbreviation: TPB3) In addition, from among these and known substances, the energy gap of the guest material 121 can be If one or more materials with a larger energy gap than 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 hole transport properties is used as a host material for the first light-emitting layer, and a substance having hole transport properties is used as a host material for the second light-emitting layer For example, a substance having an electron transport property is used as the light emitting element.

[0243] In the light-emitting layer 120, the host material 122 is composed of one kind of compound. Alternatively, the light-emitting layer 120 may be made up of a single compound or a plurality of compounds. The layer may contain materials other than the host material 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 host material 142 (phosphorescent material) of the light-emitting layer 140 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 It is preferable that the level is higher than 1.

[0245] Organic compounds 142_1 include zinc and aluminum metal complexes, as well as oxadiazo derivatives, triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzyl Dibenzoquinoxaline derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, pyrimidin 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 that can form an exciplex with the organic compound 142_1. Specifically, the electron transport material and the hole transport material shown in Embodiment 1 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 formed exciplex is the triplet MLCT( Metal to Ligand Charge Transfer (MLC) 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 material 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 absorption band of the singlet state. Preferably it is a band.

[0247] As the guest material 141 (phosphorescent material), an organic compound of iridium, rhodium, or platinum is used. Metal complexes, or metal complexes, among which organic iridium complexes, e.g., iridium The orthometalated complex is preferably a 4H-triazole. Ligand, 1H-triazole ligand, imidazole ligand, pyridine ligand, pyrimidine The metal complexes include a pyrazine ligand, an isoquinoline ligand, and the like. Examples 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. The material capable of converting triplet excitation energy into luminescence is a phosphorescent material. 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 triplet excited states by reverse intersystem crossing. The material may be capable of generating a doublet excited state, or may be an exciplex (or It may be made up of multiple materials that form a composite (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 compounds of the same type. In this case, the compound forming the above-mentioned exciplex is The combination of compounds that readily accept electrons and compounds that readily accept holes is It is particularly preferred to use

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

[0253] In addition, the light emission colors of the light emitting materials contained in the light emitting layers 120, 140, and 170 are There is no limitation, and they may be the same or different. The light emitted from each is mixed. For example, if the colors of the two lights are complementary to each other, The element can provide 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. It is preferable that:

[0254] The light-emitting units 106, 108, 110, and the charge generating The layer 115 can be formed by a deposition method (including a vacuum deposition method), an inkjet method, a coating method, a gravure printing method, etc. It can be formed by the method described above.

[0255] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. You can be there.

[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) taken along lines AB and CD. This light emitting device is a cross-sectional view of a light emitting element. The illustrated drive circuit section (source side drive circuit) 601, pixel section 602, drive circuit section (gate side The driving circuit 603 is also included. 604 is a sealing substrate, 625 is a desiccant, and 605 is a shielding material. 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 signals, and the FPC (flexible printed circuit board) is the external input terminal. Video signal, clock signal, start signal, reset signal, etc. from the input circuit 609 Although only the FPC is shown here, this 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. The driving circuit section and the pixel section are formed in the pixel 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 drive circuit is a CMOS circuit that combines various CMOS circuits, P It may be formed of a MOS circuit or an NMOS circuit. Although this shows a driver integrated type in which the driver circuit is formed on the board, this is not necessarily required. It can also 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 first An insulator 614 is formed to cover the end of the electrode 613. It can be formed by using a photosensitive resin film of a mold.

[0261] In addition, in order to improve the coverage of the film formed on the insulator 614, The upper end or the lower end of the insulator 614 is formed to have a curved surface. 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 border material 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 large material, for example, an ITO film or an indium-silicon-containing film. 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 aluminum-based film stack, titanium nitride film and aluminum-based film stack A three-layer structure of a titanium nitride film and a titanium oxide film can be used. The resistance as an anode is low, good ohmic contact can be achieved, and the anode functions as well. It is possible.

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

[0264] Furthermore, a material used for the 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 their alloys or compounds) 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 formed with a thin film. The metal thin film and the transparent conductive film (ITO, an oxide 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 present embodiment, a light emitting device having the configuration described in the first and second embodiments is used. 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 sealing material 605. A light emitting element is disposed in a space 607 surrounded by a sub-substrate 610, a sealing substrate 604, and a sealing material 605. 618 is provided. The space 607 is filled with a filler. In addition to cases where inert gas (nitrogen, argon, etc.) is filled, resin or 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 be 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 polyethylene or acrylic can be used.

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

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

[0270] FIG. 6A shows a substrate 1001, an underlying insulating film 1002, a gate insulating film 1003, and a gate electrode. 1006, 1007, 1008, a first interlayer insulating film 1020, and 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 the light-emitting element. 4W, 1024R, 1024G, 1024B, partition 1026, EL layer 1028, light-emitting element 10, a second electrode 1029, a sealing substrate 1031, a sealing material 1032, and the like are shown.

[0271] 6(A) and 6(B) show colored layers (red colored layer 1034R, green colored layer 10 34G, blue colored layer 1034B) is provided on the transparent substrate 1033. A black matrix 1035 may be further provided. The transparent substrate 1033 is aligned and fixed to the substrate 1001. The color layer is covered with an overcoat layer 1036. In FIG. 6(A), the light The light-emitting layer emits light to the outside without passing through the colored layer, and the light-emitting layer emits light to the outside by passing through the colored layer 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 expressed using four color pixels.

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

[0273] In the light emitting device described above, 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 connecting electrode that connects the TFT and the anode of the light-emitting element can be formed. The process is the same as that for 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 plays a role of planarization. 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] The first lower electrodes 1025W, 1025R, 1025G, and 1025B of the light-emitting element are Although the anode is used, it can also be the cathode. In the case of an optical device, the bottom 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. It is preferable that 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 Figures 6(A), 6(B), and 7, the EL layer configuration that can obtain 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 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) positioned between the pixels. A coloring layer (red coloring layer 1034R, 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] Although an example of full-color display using four colors, red, green, blue, and white, is shown here, there is no particular limitation. 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, the 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 combined with other embodiment modes as appropriate.

[0281] (Fourth embodiment) 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 EL, which has a flat surface and good luminous efficiency. Furthermore, according to one embodiment of the present invention, a highly reliable electronic device can be manufactured. In addition, according to one embodiment of the present invention, a flexible electronic device can be manufactured. Therefore, 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. Personal computers, computer monitors, digital cameras, digital video cameras Cameras, digital photo frames, mobile phones, portable game consoles, personal digital assistants, sound reproduction Examples include large gaming machines such as pachinko machines.

[0284] Furthermore, 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 in a child book terminal or the like.

[0285] The mobile 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)) as shown in Fig. 8(B). This makes it highly portable when you carry it around, and the large display area makes it easy to see when you use it. Excellent recognition.

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

[0288] The light-emitting device manufactured according to one embodiment of the present invention can be used in the display portion 903. This allows the production of portable information terminals with a high yield.

[0289] The display unit 903 can display 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 follows.

[0290] When the mobile information terminal 900 is unfolded, the display portion 903 is held in a greatly 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 held by the housing 901 and the other parts. Pixels are arranged continuously from 902 to 903, enabling a curved display.

[0291] The display unit 903 functions as a touch panel and can be operated with a finger or a stylus. can.

[0292] The display unit 903 is preferably configured as a single flexible display. This allows for continuous, uninterrupted display between the housing 901 and the housing 902. It should be noted that the housing 901 and the housing 902 each have a display. You may do so.

[0293] The hinge portion 905 is a part 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 between 90 degrees and 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 part 905 has a locking mechanism, the display part 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 a ridge 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 can send and receive data over computer networks.

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

[0298] The light-emitting device manufactured according to one embodiment of the present invention can be used in the display portion 912. This allows the production of 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 entering text, can be performed by touching the display 912 with a finger or a stylus. It can be done.

[0300] In addition, by operating the operation button 913, the power can be turned on and off, and the display on the display unit 912 can be changed. For example, you can change the type of image displayed from the main screen of 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 installed inside the portable information terminal 910. By providing this, the orientation (portrait or landscape) of the mobile information terminal 910 can be determined and the screen of the display unit 912 can be displayed. The display orientation can be automatically switched. The input is made by touching the display 912, operating the operation button 913, or by voice input using the microphone 916. It can also be done by 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. It has multiple functions. Specifically, it can be used as a smartphone. The information terminal 910 can be used for, for example, mobile phone calls, e-mails, viewing and creating documents, playing music, and watching videos. 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, operation buttons 923, a shutter, and a 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 in 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.

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

[0307] The camera 920 can be equipped with a strobe device, a 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, an operation key 9005 (power switch or operation switch switch), connection terminal 9006, sensor 9007 (force, displacement, position, speed, acceleration, angle Speed, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, Includes the ability to measure voltage, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared. It has a microphone 9008, etc.

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

[0310] The electronic devices shown in Figures 9(A) to 9(E) can have various functions. Functions for displaying various information (still images, videos, text images, etc.) on the display, touch panel function Functions such as displaying calendars, dates, or times, and various software (programs) ) to control processing, wireless communication function, and various computer It has the function of connecting to a data network, and the function of transmitting or receiving various data using wireless communication. The function to be performed, read 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 also 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 a terminal for mobile phone, e-mail, document viewing and creation, It can be used for various applications such as music playback, internet communication, and computer games. The display surface of the display unit 9001 is curved, and the curved The portable information terminal 9200 can display information along the display surface. For example, it is possible to use a wireless headset with short-distance wireless communication. By communicating with each other, hands-free conversation is also possible. 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 using 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] 9(C) to 9(E) are perspective views showing a foldable mobile information terminal 9202. 9C is a perspective view of the mobile information terminal 9202 in an unfolded state, and FIG. 9D is a perspective view of the mobile information terminal 9202 in an unfolded state. 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 wide and has no distortion, making it easy to see the display. 9001 is supported by three housings 9000 connected by hinges 9055. The two housings 9000 are bent via the hinge 9055, thereby forming a portable information terminal 9 202 can be reversibly transformed from an unfolded state to a folded state. 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, Therefore, a highly reliable lighting device with good luminous efficiency can be manufactured.

[0318] By fabricating the light-emitting element of one embodiment of the present invention over a flexible substrate, it is possible to fabricate a light-emitting element having a curved surface. It is possible to realize electronic devices and lighting devices having light-emitting regions.

[0319] Furthermore, 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 the multifunction terminal 3500, and FIG. 10(B) shows a perspective view of the multifunction terminal 3500. 3 shows a perspective view of the other side of the multifunction terminal 3500. The multifunction terminal 3500 has a housing 350 2 incorporates a display unit 3504, a camera 3506, a light 3508, etc. The light emitting device of the embodiment can be used for lighting 3508.

[0321] The light source 3508 functions as a surface light source when the light-emitting device of one embodiment of the present invention is used. 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 flashes, and the camera 3506 The lighting 3508 has a function as a surface light source, so it can capture images in a 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. 9(A) to 9(C). As with the electronic device shown in FIG.

[0323] In addition, inside the housing 3502, a speaker, a sensor (force, displacement, position, velocity, acceleration, angle Speed, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, Includes functions to measure voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays The multifunction terminal 3500 may include a voice recorder, a microphone, etc. By providing a detection device having a sensor that detects tilt, 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. You can make it so that it switches.

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

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

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

[0327] The Light 3600 can emit light in any direction, so it can be used to target, for example, thugs. It can be used to scare off predators with light or light and sound. The device may be provided with a camera such as a still camera, thereby providing a function for taking pictures.

[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 the above structure, a lighting device 8502 having a curved light-emitting area can be formed. The light-emitting element shown in this embodiment mode has a thin film shape, and the housing can be designed with a high degree of freedom. Therefore, it is possible to create lighting devices with various elaborate designs. A large lighting device 8503 may be provided on the wall. A touch sensor may be provided in 503 to turn the power on or off.

[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 allows the lighting device to function as furniture.

[0330] In this manner, a lighting device and an electronic device can be obtained by applying the light-emitting device of one embodiment of the present invention. 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 mode may be used in appropriate combination with structures described in other embodiments. You can be there. [Example]

[0332] Example 1 In this example, a fabrication 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 explained. A cross-sectional view of the device structure fabricated 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 light-emitting element 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 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 hole injection properties, so 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, which has a high refractive index, as an electron donating material. 111 is expected to have a high refractive index. However, as shown in FIG. 12, the hole injection layer 1 The refractive index of the film in which MoO3 (11) was added to each organic compound was 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, a material with a high refractive index can be used as an electron donor. It was found that a hole injection layer 111 with a low refractive index could be obtained even if a material other than SiO 2 was used.

[0340] 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 Extraordinary was small. That is, the mixed film of MoO3, which is an electron-accepting material, and organic compounds has different properties compared to organic compound films. It was found that the axiality decreased.

[0341] <Fabrication of light-emitting element> <Fabrication of Comparative Light-Emitting Elements 1 to 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)- ... (DBT3P-II) and MoO3 in a weight ratio of (DBT The ratio of 3P-II:MoO3 was 2:0.5 and the thickness was 1 nm. The value of x1 differs depending on the light-emitting element, and the value of x1 for each light-emitting element is 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 vapor deposition was carried out so that

[0344] Next, a light-emitting layer 130(1) was formed on the hole transport layer 112 using a mixture of 4,6mCzP2Pm and P CCP and Ir(pbi-diBuCNp)3 (a mixture of fac isomers and mers in a ratio of 3:2) The weight ratio (4,6mCzP2Pm:PCCP:Ir(pbi-diBuCNp)3) is 0. Co-evaporation was carried out to a thickness of 20 nm in a ratio of 5:0.5:0.1, followed by CVD. The optical layer 130(2) is made of a material having a weight ratio of (4.6mCzP2Pm:PCCP:Ir(pbi-d The ratio of iBuCNp3) 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 film was deposited on the light-emitting layer 130(2) as the first electron transport layer 118(1). P2Pm was co-deposited to a thickness of 20 nm. On the second electron transport layer 118(1), bathophenanthroline (abbreviated as BPhe) was deposited. 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, in a glove box with a nitrogen atmosphere, the device is sealed using an organic EL sealing material. By fixing the glass substrate for the organic material to the glass substrate on which the organic material was formed, comparative light-emitting element 1 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 a glass substrate for sealing is attached to the substrate. 365nm ultraviolet light at 6J / 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, and 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 depositing 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 x 2 nm. The value of x2 differs for each 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 process for forming the comparative light-emitting element 1 to the comparative light-emitting element 2. The same procedure was carried out as for element 4.

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

[0353] <Light-emitting element characteristics> Next, the comparative light-emitting elements 1 to 4 and the light-emitting elements 5 to 1 fabricated above were The characteristics of 2 were measured. The luminance and CIE chromaticity were measured using a color luminance meter (Topcon, BM A multichannel spectrometer (Hamamatsu Photonics) was used to measure the electroluminescence spectrum. The measurement of each light-emitting element was carried out in an atmosphere maintained at room temperature (23°C). It was conducted in a humid atmosphere.

[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 Figure 13. The external quantum efficiency The brightness characteristics are shown in Figure 15. The external quantum efficiency values ​​shown in Figure 15 are corrected for viewing angles. The external quantum efficiency is measured from the front of the light-emitting element, not from the hole injection 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 the light-emitting element 1 is an element using TAPC. All of the parts have the same element structure.

[0355] As can be seen from 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 SiO2-based SiO2 nanotubes had good hole injection properties.

[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 100 A and the external quantum efficiency exceeded 30%. In addition, organic compounds with low refractive indexes, dmCBP and TAPC, were used for the hole injection layer 111. Light-emitting devices 5 and 9 are comparative light-emitting devices using DBT3P-II, a material with a high refractive index. It showed higher efficiency than Photonic Device 1.

[0357] Furthermore, the comparative light-emitting element 1, the light-emitting element 5, and the light-emitting element 9 were each supplied with a current of 25 mA / cm 2 Current at a current density of The emission spectra when the comparative light-emitting element 1 and the light-emitting element 2 were flowed are shown in FIG. 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 elements 1 to 4 and the light-emitting elements 5 to 12 cd / m 2 The device characteristics in the vicinity are shown in Table 4. The external quantum efficiency shown in Table 4 is corrected for viewing angle. The external quantum efficiency after the test is shown.

[0359] [Table 4]

[0360] From the above results, it can be seen that the comparative light-emitting elements 1 to 4 and 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> Using the values ​​of each element shown in Table 4, the organic materials used in each hole injection layer 111 are shown in FIG. 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 ​​of elements 5 to 8 are shown in the "TAPC" curve data, and the values ​​of elements 9 to 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, the thickness of the hole injection layer 111 may be different depending on the type of the active material. 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 elements using the same light-emitting material, the optical path length from the light-emitting region of each light-emitting element 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, it can be said that 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 can be seen from 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. This is because the external quantum efficiency is higher when the wavelength is smaller. 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 could be obtained while maintaining the above.

[0365] <Volume ratio of electron donor material to electron acceptor material 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 compounds listed above.

[0366] [ka]

[0367] [Table 5]

[0368] [Table 6]

[0369] <Fabrication of Light-Emitting Elements 13 to 18> The fabrication processes of the light-emitting elements 13 to 18 are the same as those 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 elements 1 to 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 thickness of the film was adjusted to 40 nm so that the ratio of BT3P-II:MoO3 was 3-y:y. The value of y differs depending on the light-emitting element, and the value of y for each light-emitting element is 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, a light-emitting layer 130(1) was formed on the hole transport layer 112 using a mixture of 4,6mCzP2Pm and P CCP and Ir(tBuppm) 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 4.6mCzP2Pm: PCCP:Ir(tBuppm)3) is 0.8:0.2:0.075, and The co-deposition was carried out so that the thickness became 20 nm. In 2), Ir(tBuppm)3 is the guest material that exhibits phosphorescence.

[0372] <Light-emitting element characteristics> 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 10,000 cd / m 2 External quantum efficiency in the vicinity of the hole injection layer 111 Figure 18 shows the relationship between the volume ratio of MoO3 and the electron donating property. For materials in the region greater than 0 and less than 0.3, the external quantum efficiency is high at 24% to 26%. The efficiency is shown, but it can be seen that the efficiency drops in the region above 0.3. In the region where the volume ratio of MoO3 is greater than 0.3, the electron-accepting material (M oO3), the refractive index of the hole injection layer 111 is increased, and therefore the light extraction efficiency is improved. On the other hand, when the volume ratio of MoO3 is greater than 0 and less than 0.3, In the lower region, the influence of the electron-accepting material (MoO3) with a large refractive index is small, and the refractive index is The refractive index of the electron donating material is smaller than that of the electron accepting material (MoO3). This strongly influences the refractive index of 1, suggesting good light extraction efficiency. 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. [Example]

[0374] In this example, a light-emitting element different from that in Example 1 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. 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 layer 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 ) is an organic compound with a low refractive index, n Ordinary, of 1.75 or less. In addition, the 4,4'-[bis(9-phenyl Fluoren-9-yl)]-triphenylamine (abbreviation: FLP2A) is an Ordin It was found that the organic compound has a low refractive index with an ary of 1.75 or less.

[0381] Furthermore, 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. and the hole injection layer 111 of the comparative light-emitting element 19 to the comparative light-emitting element 22 is 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 elements 19 to 22 is the same as that of the comparative light-emitting elements 1 to 22. The manufacturing process of the device 4 differs from that of the device 1 only in the manufacturing process of the hole injection layer 111 and the light emitting layer 130, and the other processes are comparable. The same procedure was carried out as for the 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 depending on the light-emitting element. The values ​​are shown in Table 8.

[0384] Next, a light-emitting layer 130(1) was formed on the hole transport layer 112 using a mixture of 4,6mCzP2Pm and P CCP and Ir(ppy) 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 only difference between the manufacturing process of the comparative light-emitting element 19 and the manufacturing process of the comparative light-emitting element 20 is the manufacturing process of the hole injection layer 111. 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 ( The ratio of mCzFLP:MoO3 was 2:0.5 and the thickness was 35 nm. DBT3P-II and MoO3 were co-evaporated, and then the weight ratio of DBT3P-II:Mo O3) was co-deposited at a ratio of 2:0.5 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 Devices 27 to 30> The fabrication process of the light-emitting elements 27 to 30 is the same as that of the comparative light-emitting elements 19 to 22. The only difference between the manufacturing process of the comparative light-emitting element 19 and the manufacturing process of the comparative light-emitting element 20 is the manufacturing process of the hole injection layer 111. 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 mixing FLP2A and MoO3 in a weight ratio of (F Co-evaporation was carried out to a thickness of 35 nm with a ratio of 2:0.5 (LP2A:MoO3). Then, DBT3P-II and MoO3 were mixed in a weight ratio (DBT3P-II:MoO3 ) was co-deposited to a thickness of 2 nm. The value of z2 differs depending on the light-emitting element, and the value of z2 for each light-emitting element is shown in Table 9.

[0389] <Light-emitting element characteristics> Next, the comparative light-emitting elements 19 to 22 and the light-emitting elements 23 to 26 were fabricated. The characteristics of the element 30 were measured in the same manner as in Example 1.

[0390] Among the light-emitting devices fabricated, the current efficiencies of comparative light-emitting device 19, light-emitting device 23, and light-emitting device 27 were The efficiency-luminance characteristics are shown in Figure 20. The current density-voltage characteristics are shown in Figure 21. The external quantum efficiency vs. luminance characteristics are shown in Figure 22. The external quantum efficiency values ​​shown in Figure 22 are corrected for viewing angles. The external quantum efficiency is measured from the front of the light-emitting element, without any measurement. The comparative light-emitting element 19 uses DBT3P-II as the 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. The elements have the same structure except for the injection layer 111 .

[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 similar current density-voltage characteristics. Therefore, similarly to Example 1, the hole injection layer 111 was found to have refractive index It was found that even when an organic compound with a low ionic strength was used, it 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, a material with a high refractive index. The efficiency was higher than that of the comparative light-emitting element 19 used.

[0393] Furthermore, the comparative light-emitting element 19, the light-emitting element 23, and the light-emitting element 27 were tested 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 around 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, it can be seen that the comparative light-emitting elements 19 to 22 and the light-emitting element The light-emitting elements 23 to 30 have good driving voltage and luminous efficiency regardless of the structure of the hole injection layer 111. It can be seen that it shows the rate.

[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 The relationship between chromaticity x and external quantum efficiency is shown in Figure 24. The data shows the values ​​of comparative light-emitting elements 19 to 22, and the data of the curve of "mCzFLP". The values ​​of light emitting element 23 to light emitting element 26 are shown in the curve data of "FLP2A", and the values ​​of light emitting element 24 are shown in the curve data of "FLP2B". The values ​​of light-emitting elements 27 to 30 were used, respectively.

[0398] As can be seen from FIG. 19, the organic compounds used in the hole injection layer 111 are DBT3P-II>mCzFLP>F 24, the refractive index increases in the order of LP2A. 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-extraction 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 could be obtained while maintaining the above. [Example]

[0400] Example 1 In this example, a fabrication 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 explained. A cross-sectional view of the device structure fabricated 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 The structures and abbreviations may be found in the above-described embodiments and examples.

[0401] [Table 11]

[0402] [Table 12]

[0403] [Table 13]

[0404] [Table 14]

[0405] <Refractive index measurement> Comparative light-emitting elements 31 to 34, light-emitting elements 35 to 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 50 and Comparative Light-Emitting Elements 31 to 34 , light-emitting elements 35 to 38, light-emitting elements 39 to 42, light-emitting elements 43 to 44, The refractive index 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 CzC used in 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 comparative light-emitting elements 47 to 50 UGH-2 (abbreviated as UGH-2) has a refractive index of 1.70 or less for all n Ordinary values. It was found to be a very low level of organic compounds.

[0407] In addition, the hole injection layer 111 is required to have hole injection properties, so 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, which has a high refractive index, as an electron donating material. 25, the hole injection layer 111 of each light-emitting element is expected to have a high refractive index. The refractive index of the film in which MoO3 (11) was added to each organic compound was 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] 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 Extraordinary was small. That is, the mixed film of MoO3, an electron donating material, and organic compounds has different properties compared to organic compound films. It was found that the axiality decreased.

[0409] In addition, Cz, which is an organic compound used in the hole injection layer 111 of the light-emitting elements 39 to 42, Si and the organic compounds 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 the same refractive index as each organic compound, The hole injection layer 111 of the comparative light-emitting elements 1 to 4 is composed of DBT3P-II and MoO3 It is expected that the refractive index will be lower than that of the mixed film.

[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)- ... (DBT3P-II) and MoO3 in a weight ratio of (DBT The ratio of 3P-II:MoO3 was 2:0.5 and the thickness was 3 nm. The value of x3 differs depending on the light-emitting element, and the value of x3 for each light-emitting element is 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 vapor deposition was carried out so that

[0413] Next, a light-emitting layer 130(1) was formed on the hole transport layer 112 using a mixture of 4,6mCzP2Pm and P CCP and Ir(ppy) 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 film was deposited on the light-emitting layer 130(2) as the first electron transport layer 118(1). P2Pm was co-deposited to a thickness of 20 nm. On the second electron transport layer 118(1), bathophenanthroline (abbreviated as BPhe) was deposited. 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, in a glove box with a nitrogen atmosphere, the device is sealed using an organic EL sealing material. By fixing the glass substrate for the organic material to the glass substrate on which the organic material was formed, comparative light-emitting element 3 Specifically, the organic layer 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 bonded together. 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. 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 hole injection layer 111 The other steps were performed in the same manner as in the comparative light-emitting elements 31 to 34. The details of the preparation method are as shown in Tables 11 to 14, so the details of the preparation method are omitted here.

[0419] <Light-emitting element characteristics> Next, the comparative light-emitting elements 31 to 34, the light-emitting elements 35 to 38, and the light-emitting elements 39 to 40 were fabricated. The characteristics of the light-emitting element 46 and the comparative light-emitting elements 47 to 50 were measured. I did the same.

[0420] Among the light-emitting elements fabricated, comparative light-emitting element 31, light-emitting element 35, light-emitting element 39, and light-emitting element FIG. 26 shows the current efficiency-luminance characteristics of the light-emitting element 43 and the comparative light-emitting element 47. The voltage characteristics are shown in Figure 27. The external quantum efficiency-luminance characteristics are shown in Figure 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 Table 1. 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 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 exceeding 90 cd / A and a high external It was found that the hole injection layer 11 had a high quantum efficiency. 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 refractive indices The efficiency was higher than that of the comparative light-emitting device 31, which uses DBT3P-II, a material with high luminous efficiency. This is because the hole injection layer 111 is made of an organic compound with a low refractive index, which allows the hole to be injected into the evanescent wave. This suggests that light attenuation due to the ion beam is suppressed.

[0422] 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 comparative light-emitting element 47 had the same excellent current density-voltage characteristics. is a current density − 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 the molecule does not have an electron-donating group. Therefore, even if a material with a low refractive index is used for the hole injection layer 111, good hole injection characteristics can be 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 to 47 2 The emission spectrum when a current is 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 Comparative Light-Emitting Device 47 has a peak at around 518 nm. It was found that this was due to the emission of Ir(ppy)3, a guest material contained in 130. It was.

[0424] In addition, comparative light-emitting elements 31 to 34, light-emitting elements 35 to 46, and comparative light-emitting elements 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, it can be seen that 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 the same structure as the light-emitting elements 111 It can be seen 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. 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 was better than that of the light-emitting element 47. In particular, the reliability of the light-emitting element 43 was good. As described above, the comparative light-emitting element 31, the light-emitting element 35, the light-emitting element 39, and the light-emitting element 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 element. 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 in FIG. 31, the organic materials used in each hole injection layer 111 were The relationship between chromaticity x and external quantum efficiency is shown in Figure 31. The data for 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 used for 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 for light emitting elements 43 to 46. The data of the curve "UGH-2" is the values ​​of the comparative light-emitting element 47 to the comparative light-emitting element 50. were used, respectively.

[0429] As can be seen from 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 exceeding 80, CzC, CzSi, FATPA, UGH-2 It is an organic compound with a low refractive index of 1.70 or less. An organic compound having a lower refractive index than the light-emitting element used in the hole injection layer 111 It was found that the light-emitting device using the evanescent device has a higher external quantum efficiency. This is because the attenuation of light due to the diffused 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, hole injection characteristics can be improved. It was found that a light-emitting element having good light extraction efficiency and good reliability could be obtained while maintaining the properties. It was. [Example]

[0431] Example 1 In this example, a fabrication 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 explained. A cross-sectional view of the device structure fabricated in this example is shown in FIG. The details of the device structure are shown in Tables 16 and 17. The structures of the compounds used are abbreviated. The names of the organic compounds are shown below. For other organic compounds, please 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 an organic It is composed only of mechanical compounds.

[0432] [ka]

[0433] [Table 16]

[0434] [Table 17]

[0435] <Refractive index measurement> Comparative light-emitting elements 51 to 54, comparative light-emitting elements 55 to 58, Refractive index of the hole injection layer 111 of the light-emitting elements 59 to 62 and the light-emitting elements 63 to 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'-tetramethylbenzoate used in the comparative light-emitting elements 51 to 54 was β-TNB and p-dopant (analysis) The mixed film of NP (purchased from Kobo Co., Ltd.) and the NP used in Comparative Light-Emitting Devices 55 to 58 The mixed film of B and p-dopant has a high refractive index, which is greater than 1.75. On the other hand, it was found that 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 was found to be lower than 1.75. .

[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, a hole injection layer 111 was formed on the electrode 101 by depositing 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, PCBBiF was deposited on the hole injection layer 111 to a thickness of 1 nm as the hole transport layer 112. The value of z1 differs depending on the light-emitting element. The z1 values ​​are shown in Table 17.

[0441] Next, 2mDBTBPDBq-II was deposited on the hole transport layer 112 as the light emitting layer 130(1). 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. 06 and a thickness of 20 nm, followed by co-evaporation of the light-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 the guest material that exhibits phosphorescence.

[0442] Next, 2mDBTB was deposited on the light-emitting layer 130(2) as the first electron transport layer 118(1). PDBq-II was co-deposited to a thickness of 20 nm. 18(1) as a second electron transport layer 118(2), and NBPhen) 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, in a glove box with a nitrogen atmosphere, the device is sealed using an organic EL sealing material. By fixing the glass substrate for the organic material to the glass substrate on which the organic material was formed, comparative light-emitting element 5 Specifically, the organic layer 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 bonded together. 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. 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 elements 55 to 58 and the light-emitting elements 59 to 66 is as follows: The steps of fabricating the comparative light-emitting elements 51 to 54 and the hole injection layer 111 The other steps were the same as those for the comparative light-emitting elements 51 to 54. The details of the preparation method are as shown in Tables 16 and 17, so the details of the preparation method are omitted here.

[0447] <Light-emitting element characteristics> Next, the comparative light-emitting elements 51 to 58 and the light-emitting elements 59 to 60 were fabricated. 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 are shown in Table 19. 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 luminous efficiency regardless of the structure of the hole injection layer 111. It can be seen that it shows the rate.

[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 materials 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 ​​of light emitting element 62 are shown in the "TAPC" curve data. A value of 66 was used.

[0451] From Table 18, when β-TNB and NPB are 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 exhibits 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 improved.

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

[0453] <Step 1: Synthesis of 4-amino-3,5-diisobutylbenzonitrile> 4-Amino-3,5-dichlorobenzonitrile 52g (280mmol), isobutyl benzoate 125g (1226mmol) of uronic acid, 260g (1226mmol) of potassium phosphate tripotassium , 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (S-phos ) 5.4 g (13.1 mmol) and 1500 mL of toluene in a 3000 mL 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 m) of tris(dibenzylideneacetone)dipalladium(0) was added. mol) was added and stirred at 130°C for 12 hours under a nitrogen stream. Add cellulose and use Celite (Wako Pure Chemical Industries, Ltd., Catalog No.: 531-16855) Florisil (Wako Pure Chemical Industries, Ltd., Catalog No.: 540-00135) / Al oxide The resulting filtrate was concentrated to give an oily solution. The resulting 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 a yield of 1.5g. The yellow oil obtained by nuclear magnetic resonance (NMR) was 4-amino-3,5 The synthesis scheme for step 1 is shown below. This is 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 resulting solution was extracted with chloroform to obtain a crude product. The product was purified by chromatography using a developing solvent of hexane:ethyl acetate = 7:1. The obtained fraction was concentrated to give an orange solid. Hexane was added to the obtained solid. The resulting mixture was filtered under suction to give 16 g of a yellow solid in a yield of 35%. The resulting yellow solid was 4-[N-(2-nitrophenyl)amino]-3,5-diisobutyl The synthesis scheme of step 2 is shown in formula (a-2) below. 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, ethanol 780 mL of tin chloride (I) was added to a 2000 mL three-neck flask and stirred. 57 g (0.3 mol) of I) 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 stirred at room temperature for 16 hours. The resulting precipitate was removed by suction filtration, washed with chloroform, and The filtrate was extracted with chloroform. Concentration gave 20 g of a white solid in 100% yield. The white solid was 4-[N-(2-aminophenyl)amino]-3,5-diisobutylbenzoyl The synthesis scheme of step 3 is shown in formula (a-3) below.

[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 benzalkonium chloride, 200 mL of acetonitrile, 6.4 g (60.0 mmol) of aldehyde was placed in a 1000 mL recovery flask and heated to 100°C. The mixture was stirred for 1 hour, and 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 filtered through a Celite / Florisil / acid filter. The resulting solution was filtered by suction through a filter aid layered with aluminum chloride and aluminum fluoride. 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 target 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 (a -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-phenylindole (Synthesized in Step 4) Hpbi-diBuCNp (1.8g) mol), tris(acetylacetonato)iridium(III) 0.43 g (0.88 m mol) 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 formula (a-5) below.

[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 isomer and me It was found that a mixture of r-isomers was obtained. 1 From H-NMR, the fac isomer 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 [Explanation of symbols]

[0464] 10: substrate, 11: electrode, 12: electrode, 15: substrate, 20: organic semiconductor layer, 30: carrier 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 organic compound, 142_1: organic compound, 142_2: organic compound, 150: 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: Drive circuit section, 1042: Peripheral section, 3054: display unit, 3500: multifunction 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 first layer, a hole transport 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 tetraarylmethane skeleton or a tetraarylsilane skeleton; the hole transport layer is located between the first layer and the light-emitting layer; the hole transport layer contains a second organic compound having a pyrrole skeleton, A light-emitting device, wherein the refractive index of the first organic compound when formed into a thin film is lower than the refractive index of the second organic compound when formed into a thin film at a wavelength of 532 nm.

2. A light-emitting device comprising a first layer, a hole transport 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 contains a first organic compound having an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms, and a tetraarylmethane skeleton or a tetraarylsilane skeleton; the hole transport layer is located between the first layer and the light-emitting layer; the hole transport layer contains a second organic compound having a pyrrole skeleton, A light-emitting device, wherein the refractive index of the first organic compound when formed into a thin film is lower than the refractive index of the second organic compound when formed into a thin film at a wavelength of 532 nm.

3. A light-emitting device comprising a first layer, a hole transport 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 tert-butyl group and a tetraarylmethane skeleton or a tetraarylsilane skeleton; the hole transport layer is located between the first layer and the light-emitting layer; the hole transport layer contains a second organic compound having a pyrrole skeleton, A light-emitting device, wherein the refractive index of the first organic compound when formed into a thin film is lower than the refractive index of the second organic compound when formed into a thin film at a wavelength of 532 nm.

4. A light-emitting device comprising a first layer, a hole transport 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 tetraarylmethane skeleton or a tetraarylsilane skeleton; the hole transport layer is located between the first layer and the light-emitting layer; the hole transport layer includes a second organic compound that is a carbazole derivative; A light-emitting device, wherein the refractive index of the first organic compound when formed into a thin film is lower than the refractive index of the second organic compound when formed into a thin film at a wavelength of 532 nm.

5. A light-emitting device comprising a first layer, a hole transport 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 contains a first organic compound having an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms, and a tetraarylmethane skeleton or a tetraarylsilane skeleton; the hole transport layer is located between the first layer and the light-emitting layer; the hole transport layer includes a second organic compound that is a carbazole derivative; A light-emitting device, wherein the refractive index of the first organic compound when formed into a thin film is lower than the refractive index of the second organic compound when formed into a thin film at a wavelength of 532 nm.

6. A light-emitting device comprising a first layer, a hole transport 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 tert-butyl group and a tetraarylmethane skeleton or a tetraarylsilane skeleton; the hole transport layer is located between the first layer and the light-emitting layer; the hole transport layer includes a second organic compound that is a carbazole derivative; A light-emitting device, wherein the refractive index of the first organic compound when formed into a thin film is lower than the refractive index of the second organic compound when formed into a thin film at a wavelength of 532 nm.

7. In any one of claims 1 to 6, The light-emitting device, wherein the first layer includes a first material having at least one of a halogen group and a cyano group.

8. In claim 7, A light-emitting device, wherein the ordinary refractive index at a wavelength of 532 nm of a thin film obtained by mixing the first organic compound and the first substance is lower than the ordinary refractive index at a wavelength of 532 nm of a thin film obtained by forming the second organic compound.

9. a first layer, a hole transport 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 tetraarylmethane skeleton or a tetraarylsilane skeleton; the hole transport layer is located between the first layer and the light-emitting layer; the hole transport layer contains a second organic compound having a pyrrole skeleton, A light-emitting device, wherein the refractive index of the first organic compound when formed into a thin film is lower than the refractive index of the second organic compound when formed into a thin film at a wavelength of 633 nm.

10. A light-emitting device comprising a first layer, a hole transport 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 contains a first organic compound having an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms, and a tetraarylmethane skeleton or a tetraarylsilane skeleton; the hole transport layer is located between the first layer and the light-emitting layer; the hole transport layer contains a second organic compound having a pyrrole skeleton, A light-emitting device, wherein the refractive index of the first organic compound when formed into a thin film is lower than the refractive index of the second organic compound when formed into a thin film at a wavelength of 633 nm.

11. A light-emitting device comprising a first layer, a hole transport 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 tert-butyl group and a tetraarylmethane skeleton or a tetraarylsilane skeleton; the hole transport layer is located between the first layer and the light-emitting layer; the hole transport layer contains a second organic compound having a pyrrole skeleton, A light-emitting device, wherein the refractive index of the first organic compound when formed into a thin film is lower than the refractive index of the second organic compound when formed into a thin film at a wavelength of 633 nm.

12. a first layer, a hole transport 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 tetraarylmethane skeleton or a tetraarylsilane skeleton; the hole transport layer is located between the first layer and the light-emitting layer; the hole transport layer includes a second organic compound that is a carbazole derivative; A light-emitting device, wherein the refractive index of the first organic compound when formed into a thin film is lower than the refractive index of the second organic compound when formed into a thin film at a wavelength of 633 nm.

13. A light-emitting device comprising a first layer, a hole transport 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 contains a first organic compound having an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms, and a tetraarylmethane skeleton or a tetraarylsilane skeleton; the hole transport layer is located between the first layer and the light-emitting layer; the hole transport layer includes a second organic compound that is a carbazole derivative; A light-emitting device, wherein the refractive index of the first organic compound when formed into a thin film is lower than the refractive index of the second organic compound when formed into a thin film at a wavelength of 633 nm.

14. A light-emitting device comprising a first layer, a hole transport 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 tert-butyl group and a tetraarylmethane skeleton or a tetraarylsilane skeleton; the hole transport layer is located between the first layer and the light-emitting layer; the hole transport layer includes a second organic compound that is a carbazole derivative; A light-emitting device, wherein the refractive index of the first organic compound when formed into a thin film is lower than the refractive index of the second organic compound when formed into a thin film at a wavelength of 633 nm.

15. In any one of claims 9 to 14, The light-emitting device, wherein the first layer includes a first material having at least one of a halogen group and a cyano group.

16. In claim 15, A light-emitting device, wherein the ordinary refractive index at a wavelength of 633 nm of a thin film obtained by mixing the first organic compound and the first substance is lower than the ordinary refractive index at a wavelength of 633 nm of a thin film obtained by forming the second organic compound.

17. In any one of claims 1 to 16, a light-emitting device, wherein the aryl groups in the tetraarylmethane skeleton and the tetraarylsilane skeleton are each independently a substituted or unsubstituted aryl group having 6 to 13 carbon atoms (the aryl groups may be bonded to each other to form a ring).

18. In any one of claims 1 to 17, The tetraarylmethane skeleton includes a fluorene skeleton having two phenyl groups as substituents on the carbon atom at the 9-position, or a spirofluorene skeleton.

19. In any one of claims 2, 5, 10, and 13, the alkyl group is at least one of a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, and an n-hexyl group; The light-emitting device, wherein the cycloalkyl group is at least one of a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group.

20. In any one of claims 1 to 19, The second organic compound has an aromatic amine skeleton.

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