Light emitting element

Abstract

To provide a light-emitting element with low driving voltage and high reliability.SOLUTION: A light-emitting element includes an electron injection layer between a cathode and a light-emitting layer. The electron injection layer is a mixed film of transition metal and an organic compound with an unshared electron pair. The transition metal atom and the organic compound form SOMO.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] One embodiment of the present invention relates to a light-emitting element having a novel electron-injection layer. The present invention relates to a display device, an electronic device, and a lighting device having the same.

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

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

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

[0005] In general, in order to reduce the driving voltage of a light-emitting element, an electron injection layer is provided between the cathode and the light-emitting layer. The electron injection layer is formed by ionizing lithium (Li) or calcium to reduce the electron injection barrier with the cathode. Alkali metals and alkaline earth metals, such as Ca, have a small work function. Metals and their compounds are used (for example, Patent Document 1).

[0006] In addition, when the above-mentioned light-emitting element is used in a light-emitting device, each sub-pixel in a pixel has a different a method of providing an EL layer having a function of emitting light of different colors (hereinafter referred to as a color-by-color method); A common EL layer having a function of, for example, providing white light to the sub-pixels in the pixel is provided, and A method of providing color filters that transmit light of different colors (hereinafter referred to as color filters) There is a method called the filter method.

[0007] The advantage of the color filter method is that the EL layer can be shared among all sub-pixels. In comparison with the separate coating method, the loss of EL layer material is small, and the process required for forming the EL layer is also reduced. This allows light-emitting devices to be manufactured at low cost and with high productivity. Next, in the color-by-color method, the EL layer materials of each subpixel are mixed with each other. To prevent this, a margin is required between each sub-pixel, but in the color filter method, this margin is not sufficient. Therefore, it is necessary to realize a light emitting device with higher pixel density and higher resolution.

[0008] The above light-emitting elements can emit a variety of colors depending on the type of light-emitting material contained in the EL layer. When considering application to lighting devices, it is necessary to have white or a similar color of light. There is a demand for highly efficient light-emitting devices that can achieve this. Considering this, there is a demand for a highly efficient light-emitting device that emits light with high color purity. Light emitting elements used in these devices are required to have low power consumption.

[0009] In order to improve the light emission efficiency of the light emitting element, it is necessary to improve the light extraction efficiency from the light emitting device. In order to improve the light extraction efficiency from the light-emitting element, it is important to The device uses a micro-optical resonator (microcavity) structure that utilizes the resonance effect of light between the Methods for increasing the light intensity at a long distance have been proposed (see, for example, Patent Document 2).

[0010] In addition, as a light-emitting element that emits white light, an element in which a charge generating layer is provided between multiple EL layers ( A new type of element, called a tandem element, has been proposed.

[0011] Regarding such light-emitting devices, in order to improve the device characteristics, improvements in the device structure and material development have been carried out. There is a lot of activity going on. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] JP 2001-102175 A [Patent Document 2] JP 2015-130319 A Summary of the Invention [Problem to be solved by the invention]

[0013] Metals with low work functions and their compounds are highly reactive with oxygen and water, making them difficult to handle. In addition, when such metals or compounds are used in light-emitting devices, they are affected by oxygen and water, and the light emission of the light-emitting device is reduced. This may result in a decrease in efficiency, an increase in drive voltage, or a decrease in reliability. There is a need to develop an electron injection layer that is less susceptible to the effects of oxygen and water and has a small electron injection barrier with the cathode. It is being considered.

[0014] In addition, the electron injection layer adjacent to the charge generation layer of the tandem element is required to have high electron injection properties. Therefore, the electron injection layer is preferably made of an alkali metal such as lithium or cesium or a compound thereof. However, the metals, such as alkaline earth metals and calcium, and their compounds are used. When the metal and the compound are used in the electron injection layer, the metal is dispersed in the electron transport layer, and crosstalk occurs. This may be a cause of problems.

[0015] In view of the above-described problems, one embodiment of the present invention is to provide a light-emitting element having a low driving voltage. Another object of one embodiment of the present invention is to provide a light-emitting element having high moisture resistance. Another object of one embodiment of the present invention is to provide a light-emitting element having high oxidation resistance. Another object of one embodiment of the present invention is to provide a light-emitting element with reduced power consumption. Another object of one embodiment of the present invention is to provide a light-emitting element with high reliability. Another object of one embodiment of the present invention is to provide a novel light-emitting element. An object of one embodiment of the present invention is to provide a novel semiconductor device. An object of one embodiment of the present invention is to provide a light-emitting element in which the occurrence of crosstalk is suppressed. Another object of one embodiment of the present invention is to provide a light-emitting element that emits light with high color purity. Let us assume that.

[0016] Another embodiment of the present invention is an electronic device or a lighting device which has high moisture resistance and which uses the light-emitting element. Another object of the present invention is to provide a light emitting device using the light emitting element. Another object of the present invention is to provide a light-emitting device with reduced power consumption. It is an object of the present invention to provide a light emitting device having a long life using the light emitting element.

[0017] Note that the above description of the object does not preclude the existence of other objects. It is not necessary to solve all of these problems. Problems other than those mentioned above can be solved by the description of the specification, etc. It is obvious from the description of the specification, etc. that other problems can be extracted. do. [Means for solving the problem]

[0018] One embodiment of the present invention has a light-emitting layer between an anode and a cathode, and a first layer between the light-emitting layer and the cathode. The first layer has a first organic compound having an unshared electron pair and a transition metal. Organic compounds and transition metals have SOMO (Single Occupied Molecular Orbital) It is a light-emitting element that forms a circular orbital.

[0019] Another embodiment of the present invention is a light-emitting device having a first light-emitting unit and a second light-emitting unit between an anode and a cathode. a first layer between the first light-emitting unit and the second light-emitting unit; the layer includes a first organic compound and a transition metal, the first organic compound having an unshared electron pair, The first organic compound and the transition metal form a SOMO, which is a light-emitting element.

[0020] Another embodiment of the present invention is a light-emitting device having a first light-emitting unit and a second light-emitting unit between an anode and a cathode. a first layer and a charge generating layer between the first light-emitting unit and the second light-emitting unit; The charge generating layer and the first layer are provided in contact with each other, and the first layer is a first organic compound and a first transition metal, the first organic compound having an unshared electron pair, and the first transition metal form a SOMO, making it a light-emitting device.

[0021] In the above-mentioned structure, it is preferable that the first organic compound has an electron-deficient heteroaromatic ring. The first organic compound has at least one of a pyridine ring, a diazine ring, and a triazine ring. and more preferably.

[0022] In the above-mentioned structure, the number of carbon atoms constituting the first organic compound is 25 or more and 100 or less. It is preferable to do so.

[0023] In the above structure, the first organic compound does not have a 1,10-phenanthroline skeleton. Very preferable.

[0024] In the above-mentioned structure, the LUMO (Lowest Unoccupied Molecular Orbital) of the first organic compound is t Unoccupied Molecular Orbital) level is -3.6 eV It is preferable that the refractive index is not less than −2.3 eV.

[0025] In the above-mentioned structure, the transition metal is a metal of Group 5, 7, 9 or 1 in the periodic table. It is preferred that the transition metal belongs to Group 1. It is more preferred that the transition metal belongs to Group 11, and Ag It is even more preferable that:

[0026] In the above-mentioned structure, a second layer is further provided between the cathode and the first layer, and the second layer is an electron It is preferred to include a second organic compound having a deficient heteroaromatic ring.

[0027] In the above structure, the LUMO level of the second organic compound is lower than the SOMO level. preferable.

[0028] In the above structure, the light-emitting element preferably does not contain an alkali metal or an alkaline earth metal. It is nice.

[0029] In the above-mentioned configuration, the molar ratio of the metal to the first organic compound in the first layer is 0. It is preferable that it be greater than .2 and less than 0.8.

[0030] In the above configuration, it is preferable that the cathode contains the same material as the metal of the first layer. It is preferable that the light-emitting layer contains a first organic compound.

[0031] Another embodiment of the present invention is a display device having any of the above structures and a housing or a touch sensor. Another embodiment of the present invention is an electronic device having the above-described structure. The present invention also provides a lighting device having an element and at least one of a housing and a touch sensor. One embodiment of the present invention is not limited to a light-emitting device having a light-emitting element, but also includes an electrical device having a light-emitting device. Therefore, the light-emitting device in this specification includes an image display device, Refers to a light source (including lighting equipment). Also, a light emitting element is connected to a connector, such as an FPC (Flexible Printed Circuit). ble Printed Circuit) or TCP (Tape Carrier The display module has a printed wiring board attached to the TCP. The display module is mounted on the substrate, or the light emitting element is made of COG (Chip On Glass) type. A display module in which an IC (integrated circuit) is directly mounted by the above method is also one embodiment of the present invention. Effect of the Invention

[0032] According to one embodiment of the present invention, a light-emitting element with low driving voltage can be provided. According to one embodiment of the present invention, a light-emitting element having high moisture resistance can be provided. In this manner, a light-emitting element having high oxidation resistance can be provided. In this way, a light-emitting element with reduced power consumption can be provided. In addition, according to one embodiment of the present invention, a novel light-emitting element having high reliability can be provided. According to one embodiment of the present invention, a novel semiconductor device can be provided. In addition, according to one embodiment of the present invention, the occurrence of crosstalk is suppressed. According to one embodiment of the present invention, a light-emitting element having high color purity can be provided. It is possible to provide a light emitting element exhibiting the above properties.

[0033] According to one embodiment of the present invention, an electronic device and a lighting device which have high moisture resistance and which use the light-emitting element can be provided. According to one embodiment of the present invention, a light emitting device to which the light emitting element is applied can be provided. According to one embodiment of the present invention, a light-emitting device having reduced power consumption can be provided. It is possible to provide a long-life light-emitting device using the element.

[0034] Note that the description of these effects does not preclude the existence of other effects. It is not necessary to have all of these effects. Effects other than these are described in the specification. The disclosure of the specification, drawings, claims, etc. is self-evident, and the disclosure of the specification, drawings, claims, etc. is self-evident. From this, it is possible to extract other effects. [Brief description of the drawings]

[0035] [Figure 1] 1A and 1B are a cross-sectional schematic diagram illustrating a light-emitting element of one embodiment of the present invention and a diagram illustrating the correlation between energy levels of an electron-injection layer. [Diagram 2]1 is a schematic cross-sectional view illustrating a light-emitting element of one embodiment of the present invention. [Diagram 3] 1 is a schematic cross-sectional view illustrating a light-emitting element of one embodiment of the present invention. [Figure 4] 1A and 1B are a top view and a cross-sectional schematic diagram illustrating a display device of one embodiment of the present invention. [Diagram 5] 1A and 1B are schematic cross-sectional views illustrating a display device according to one embodiment of the present invention. [Figure 6] 1A and 1B are schematic cross-sectional views illustrating a display device according to one embodiment of the present invention. [Figure 7] FIG. 1 is a cross-sectional view illustrating an example of a transistor. [Figure 8] 1A to 1C illustrate electronic devices of one embodiment of the present invention. [Figure 9] FIG. 1 is a perspective view illustrating a display device according to one embodiment of the present invention. [Figure 10] 1A to 1C are diagrams illustrating a lighting device according to one embodiment of the present invention. [Figure 11] 1A to 1C are diagrams illustrating a lighting device according to one embodiment of the present invention. [Figure 12] 1 is a schematic cross-sectional view illustrating a light-emitting element according to an embodiment. [Figure 13] FIG. 13 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 14] FIG. 13 is a graph showing current density-voltage characteristics of a light-emitting element in the example. [Figure 15] FIG. 13 is a graph showing power efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 16] FIG. 13 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Figure 17] FIG. 2 is a graph showing electroluminescence spectra of light-emitting elements according to an embodiment of the present invention. [Figure 18] FIG. 4 is a diagram illustrating the absorption spectrum of a thin film in an example. [Figure 19] FIG. 4 is a diagram illustrating the absorption spectrum of a thin film in an example. [Figure 20] FIG. 4 is a diagram illustrating the absorption spectrum of a thin film in an example. [Figure 21] FIG. 13 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 22] FIG. 13 is a graph showing current-voltage characteristics of a light-emitting element in the embodiment. [Figure 23] FIG. 13 is a graph showing power efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 24] FIG. 13 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Diagram 25] FIG. 2 is a graph showing electroluminescence spectra of light-emitting elements according to an embodiment of the present invention. [Figure 26] FIG. 4 is a diagram illustrating the absorption spectrum of a thin film in an example. [Figure 27] FIG. 13 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 28] FIG. 13 is a graph showing current density-voltage characteristics of a light-emitting element in the example. [Figure 29] FIG. 13 is a graph showing power efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Diagram 30] FIG. 13 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Diagram 31] FIG. 2 is a graph showing electroluminescence spectra of light-emitting elements according to an embodiment of the present invention. [Diagram 32] FIG. 13 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Diagram 33] FIG. 13 is a graph showing current-voltage characteristics of a light-emitting element in the embodiment. [Diagram 34] FIG. 13 is a graph showing power efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Diagram 35] FIG. 13 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Diagram 36] FIG. 2 is a graph showing electroluminescence spectra of light-emitting elements according to an embodiment of the present invention. [Figure 37] 1 is a schematic cross-sectional view illustrating a light-emitting element according to an embodiment. [Figure 38] FIG. 13 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 39] FIG. 13 is a graph showing current density-voltage characteristics of a light-emitting element in the example. [Diagram 40]FIG. 13 is a graph showing power efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Diagram 41] FIG. 13 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Diagram 42] FIG. 2 is a graph showing electroluminescence spectra of light-emitting elements according to an embodiment of the present invention. [Diagram 43] 11A to 11C are diagrams illustrating the results of a driving life test of a light-emitting element according to an example. [Diagram 44] 11A to 11C are diagrams illustrating the results of a driving life test of a light-emitting element according to an example. [Diagram 45] 11A to 11C are diagrams illustrating the results of a driving life test of a light-emitting element according to an example. [Diagram 46] FIG. 13 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 47] FIG. 13 is a graph showing current-voltage characteristics of a light-emitting element in the embodiment. [Figure 48] FIG. 2 is a graph showing electroluminescence spectra of light-emitting elements according to an embodiment of the present invention. [Figure 49] 1 is a schematic cross-sectional view illustrating a light-emitting element of one embodiment of the present invention. [Figure 50] 1 is a schematic cross-sectional view illustrating a light-emitting element of one embodiment of the present invention. [Figure 51] 1 is a schematic cross-sectional view illustrating a light-emitting element according to an embodiment. [Figure 52] 1 is an enlarged photograph of a light-emitting element according to an embodiment. [Figure 53] 6A and 6B are diagrams for explaining the relationship between brightness and distance from adjacent pixels in the embodiment. [Figure 54] 1 is a schematic cross-sectional view illustrating a light-emitting element according to an embodiment. [Figure 55] FIG. 13 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 56] FIG. 13 is a graph showing current density-voltage characteristics of a light-emitting element in the example. [Figure 57] FIG. 13 is a graph showing power efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 58] FIG. 13 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Figure 59]FIG. 2 is a graph showing electroluminescence spectra of light-emitting elements according to an embodiment of the present invention. [Figure 60] FIG. 13 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 61] FIG. 13 is a graph showing current density-voltage characteristics of a light-emitting element in the example. [Figure 62] FIG. 13 is a graph showing power efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 63] FIG. 13 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Figure 64] FIG. 2 is a graph showing electroluminescence spectra of light-emitting elements according to an embodiment of the present invention. [Figure 65] FIG. 13 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 66] FIG. 13 is a graph showing current density-voltage characteristics of a light-emitting element in the example. [Figure 67] FIG. 13 is a graph showing power efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 68] FIG. 13 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Figure 69] FIG. 2 is a graph showing electroluminescence spectra of light-emitting elements according to an embodiment of the present invention. [Figure 70] 1 is a schematic cross-sectional view illustrating a light-emitting element according to an embodiment. [Figure 71] FIG. 13 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 72] FIG. 13 is a graph showing current-voltage characteristics of a light-emitting element in the embodiment. [Figure 73] FIG. 13 is a graph showing power efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 74] FIG. 13 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Figure 75] FIG. 2 is a graph showing electroluminescence spectra of light-emitting elements according to an embodiment of the present invention. [Figure 76] FIG. 13 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 77] FIG. 13 is a graph showing current-voltage characteristics of a light-emitting element in the embodiment. [Figure 78] FIG. 13 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Figure 79] FIG. 2 is a graph showing electroluminescence spectra of light-emitting elements according to an embodiment of the present invention. [Figure 80] FIG. 13 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 81] FIG. 13 is a graph showing current-voltage characteristics of a light-emitting element in the embodiment. [Figure 82] FIG. 13 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Figure 83] FIG. 2 is a graph showing electroluminescence spectra of light-emitting elements according to an embodiment of the present invention. [Figure 84] FIG. 13 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 85] FIG. 13 is a graph showing current-voltage characteristics of a light-emitting element in the embodiment. [Figure 86] FIG. 13 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Figure 87] FIG. 2 is a graph showing electroluminescence spectra of light-emitting elements according to an embodiment of the present invention. [Figure 88] FIG. 4 is a diagram illustrating the relationship between the LUMO level of an organic compound and the emission area ratio after a constant temperature and humidity storage test in an example. [Figure 89] 1 is a schematic cross-sectional view illustrating a light-emitting element according to an embodiment. [Figure 90] FIG. 13 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 91] FIG. 13 is a graph showing current-voltage characteristics of a light-emitting element in the embodiment. [Figure 92] FIG. 13 is a graph showing power efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 93] FIG. 2 is a graph showing electroluminescence spectra of light-emitting elements according to an embodiment of the present invention. [Figure 94] FIG. 13 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 95] FIG. 13 is a graph showing current-voltage characteristics of a light-emitting element in the embodiment. [Figure 96] FIG. 13 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Figure 97] FIG. 2 is a graph showing electroluminescence spectra of light-emitting elements according to an embodiment of the present invention. [Figure 98] FIG. 13 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 99] FIG. 13 is a graph showing current-voltage characteristics of a light-emitting element in the embodiment. [Figure 100] FIG. 13 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Figure 101] FIG. 2 is a graph showing electroluminescence spectra of light-emitting elements according to an embodiment of the present invention. [Figure 102] FIG. 13 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Figure 103] FIG. 13 is a graph showing current-voltage characteristics of a light-emitting element in the embodiment. [Figure 104] FIG. 13 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Figure 105] FIG. 2 is a graph showing electroluminescence spectra of light-emitting elements according to an embodiment of the present invention. [Fig. 106] 11A to 11C are diagrams illustrating the results of a driving life test of a light-emitting element according to an example. [Figure 107] FIG. 1 is a diagram illustrating the results of ESR (Electron Spin Resonance) measurements according to an embodiment. [Figure 108] FIG. 13 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element in the embodiment. [Fig. 109] FIG. 13 is a graph showing current-voltage characteristics of a light-emitting element in the embodiment. [Figure 110] FIG. 13 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an embodiment. [Figure 111] FIG. 2 is a graph showing electroluminescence spectra of light-emitting elements according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] Hereinafter, the embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the above description, and the embodiments and details thereof are not limited to those described above without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the embodiments described below. The terms of the present disclosure are not to be construed as being limited to the content.

[0037] In addition, the position, size, range, etc. of each component shown in the drawings are not necessarily shown in order to facilitate understanding. The actual position, size, range, etc. may not be shown. The present invention is not necessarily limited to the position, size, range, etc. disclosed in the drawings, etc.

[0038] In addition, in this specification, ordinal numbers such as 1st, 2nd, etc. are used for convenience. In some cases, the order of steps or layers may not be indicated. For example, "first" may be replaced with "second" or " " can be appropriately replaced with "the third" etc. The ordinal numbers used to identify an aspect of the present invention may not match those used in the present invention. be.

[0039] In addition, in this specification and the like, when explaining the configuration of the invention using drawings, The reference numerals are used commonly among different drawings.

[0040] 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:

[0041] (Embodiment 1) In this embodiment, a light-emitting element of one embodiment of the present invention will be described below with reference to FIG.

[0042] <Configuration example 1 of light-emitting element> FIG. 1A is a schematic cross-sectional view of a light-emitting element 150 of one embodiment of the present invention.

[0043] The light emitting element 150 has a pair of electrodes (electrode 101 and electrode 102). The EL layer 100 includes at least a light-emitting layer 140 and an electron-emitting layer 142. It has an injection layer 130 .

[0044] In addition, the EL layer 100 shown in FIG. 1(A) includes a positive electrode in addition to the light-emitting layer 140 and the electron injection layer 130. It has functional layers such as a hole injection layer 111, a hole transport layer 112, and an electron transport layer 118.

[0045] In this embodiment, of the pair of electrodes, the electrode 101 is an anode, and the electrode 10 Although the description will be given assuming that 2 is a cathode, the configuration of the light emitting element 150 is not limited to this. Electrode 101 is a cathode, electrode 102 is an anode, and the layers between the electrodes are stacked in the reverse order. That is, from the anode side, a hole injection layer 111, a hole transport layer 112, and a light emitting layer The layer 140, the electron transport layer 118, and the electron injection layer 130 may be stacked in this order.

[0046] The configuration of the EL layer 100 is not limited to the configuration shown in FIG. 1(A). 140 and an electron injection layer 130, and 118, each of which may or may not be present.

[0047] In addition, in the EL layer between the pair of electrodes, each layer may be formed according to its function. That is, the EL layer between the pair of electrodes is not limited to a material that reduces the injection barrier for holes or electrons. , improve the transportability of holes or electrons, inhibit the transportability of holes or electrons, or It may be configured to have a layer having a function of suppressing the quenching phenomenon due to the .

[0048] The light-emitting layer 140 preferably contains a host material and a guest material (light-emitting material). stomach.

[0049] In addition, as the host material, a material having a function of transporting holes (hole transport property) is used. and materials that have the function of transporting electrons (electron transport properties) (electron transporting materials). It is preferable to use either one or both of them. Fees may also be used.

[0050] In addition, when the host material is a combination of an electron transporting material and a hole transporting material, The carrier balance can be easily controlled by the mixture ratio of the two. The electron transport material:hole transport material ratio is preferably in the range of 1:9 to 9:1 (weight ratio). By having this configuration, the carrier balance can be easily controlled. The rear recombination region can also be easily controlled.

[0051] In addition, a light-emitting compound may be used as the guest material. is a substance that can emit fluorescence (hereinafter referred to as a fluorescent compound) or phosphorescence. It is preferable that the material be a substance capable of emitting phosphorescence (hereinafter also referred to as a phosphorescent compound).

[0052] In order to reduce the driving voltage of the light-emitting device, electron injection between the light-emitting layer 140 and the electrode 102 is required. Therefore, an electron injection layer is provided between the light-emitting layer 140 and the electrode 102. In the conventional light-emitting device, the electron injection layer 130 has a work function. Metallic materials containing alkali metals and alkaline earth metals with small atomic numbers are used. However, metal materials with small work functions are highly reactive with oxygen and water, so when used in light-emitting devices, The light emission efficiency decreases, the driving voltage increases, the element life decreases, and shrinkage (at the edge of the light-emitting part) occurs. This may cause non-light-emitting areas, leading to deterioration of the characteristics and reliability of the light-emitting element. In other words, metal materials with a small work function can be a cause of element degradation. In order to suppress the deterioration of the characteristics and reliability of the light-emitting element, the light-emitting element should be made of alkali metal and It is preferred that the catalyst is free of alkaline earth metals.

[0053] On the other hand, metals with a large work function have low reactivity with oxygen and water, but are used for the electron injection layer 130. In this case, an electron injection barrier is formed between the electrode 102, and the driving voltage of the light-emitting element increases. Furthermore, there is a problem that the luminous efficiency decreases.

[0054] Here, the present inventors have discovered that the interaction between a compound having an unshared electron pair and a transition metal leads to A composite material of a compound that forms a SOMO and a transition metal is prepared. By using it in the electron injection layer, the electron injection barrier between the electron injection layer and the cathode is reduced and moisture resistance is improved. It has been found that an excellent light-emitting device can be obtained.

[0055] SOMO is formed by the interaction of a compound with an unshared electron pair with a transition metal. For this reason, it is preferable that the total number of electrons in the compound and the transition metal is an odd number. If the compound has an even electron count, the transition metal is preferably from an odd group in the periodic table. Also, if the compound has an odd number of electrons, the transition metal is an even-numbered group in the periodic table. It is preferable to do so.

[0056] In addition, compounds with unshared electron pairs include organic compounds that have the function of transporting electrons. Also preferred is an organic compound that functions as an electron acceptor for the transition metal.

[0057] Therefore, the light-emitting element of one embodiment of the present invention is a composite of an organic compound having an unshared electron pair and a transition metal. The material is used in an electron injection layer of a light-emitting device.

[0058] Transition metals have low reactivity with water and oxygen, so when used in light-emitting elements, they have a small work function. There is little risk of element deterioration due to water or oxygen, which is a concern when using metal. One embodiment can provide a light-emitting element with excellent moisture resistance and oxidation resistance.

[0059] FIG. 1B is a schematic diagram of an electron-injection layer 130 in a light-emitting element of one embodiment of the present invention. The electron injection layer 130 includes a compound 131 and a transition metal 132 having an unshared electron pair.

[0060] FIG. 1C shows an energy distribution in the electron-injection layer 130 of a light-emitting element according to one embodiment of the present invention. The diagram shows that when transition metal 132 is mixed with compound 131, compound 131 undergoes a transition By interacting with the atom of metal 132, a SOMO is formed. In this case, compound 13 The HOMO (Highest Occ Molecular Orbital) formed by the interaction of 1 with the transition metal atom 132 The superimposed molecular orbital levels are the H levels of the original compound 131. It is preferable that the OMO level is the same as that of the compound 131. In the case of using the compound 131, the HOMO level of the compound 131 is low, and the hole is injected into the compound 131. Therefore, the compound 131 and the transition metal 132 atoms interact to form If the HOMO level of the electron-injecting layer is equivalent to that of the original compound 131, Since the hole injection barrier between the electron injection layer 130 and the electrode 102 is large, This is preferable because holes are less likely to escape to 102, and the carrier balance in the light-emitting element can be improved. In this specification, HOMO refers to the molecular orbital with the highest energy that is filled with electrons. Point the way.

[0061] Since the SOMO is an orbital that has only one electron, when a voltage is applied to the light-emitting element 150, S The electrons in the OMO become carriers in the light-emitting element and are transported to the electron transport layer 118 and the light-emitting layer 140. In addition, electrons can be easily injected from the electrode 102 into the electron injection layer 130. That is, the electron injection layer 130 has a combination of materials that form a SOMO. Therefore, electrons can be easily injected from the electrode 102 into the EL layer 100. It is preferable that the O level is lower than the LUMO level of compound 131. The LUMO level of compound 31 is preferably high. Specifically, the LUMO level of compound 131 is - The LUMO level is preferably 3.6 eV or more and -2.3 eV or less. When an organic compound is mixed with a transition metal, the SOMO level formed by the interaction is suitable for electron injection. This reduces the electron injection barrier between the electron injection layer 130 and the electrode 102. It is possible.

[0062] The HOMO and LUMO levels of organic compounds are generally measured by CV (cyclic voltammetry). It is estimated by photoelectron spectroscopy, optical absorption spectroscopy, inverse photoelectron spectroscopy, etc. When comparing values ​​between different compounds, it is recommended to use values ​​estimated from the same measurement. preferable.

[0063] Here, the above-mentioned transition metal preferably belongs to any one of Groups 5, 7, 9, and 11. Among these odd-numbered transition metals, the metals that have one electron (unpaired electron) in the outermost orbit are is particularly preferred because it easily forms a SOMO with compound 131.

[0064] <Quantum chemical calculation of SOMO levels in the interaction between transition metal 132 and compound 131> Get a quote > Here, in order for compound 131 and transition metal 132 to form a SOMO, compound 131 must be Therefore, organic compounds need to interact with various transition metal atoms. Stabilization energy in the case of interaction and the interaction of organic compounds with transition metal atoms The SOMO levels formed when the nuclei were bonded were estimated by quantum chemical calculations. The results are shown in Table 1. The organic compound having an unshared electron pair was the 2,9- Bis(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation The name NBPhen was used.

[0065] [ka]

[0066] [Table 1]

[0067] The quantum chemical calculation program used was Gaussian09. The experiment was carried out using a high-performance computer (ICE X, manufactured by SGI). The ground state of the element, the ground state of the transition metal, and the ground state of the composite material of the organic compound and the transition metal The most stable structure in the bottom state was calculated using density functional theory (DFT). 311G(d,p) and LanL2DZ were used, and B3LYP was used as the functional. Next, the total energy of the composite material of the organic compound and the transition metal and the total energy of the organic compound alone are calculated. The stabilization energy was calculated from the difference between the sum of the total energy of the transition metal and the transition metal element. That is, (stabilization energy) = (total energy of the composite material of the organic compound and the transition metal) - (Total energy of organic compound alone) - (Total energy of transition metal alone). The total energy of FT is the potential energy, the electrostatic energy between electrons, and the kinetic energy of electrons. It is expressed as the sum of the exchange-correlation energy, which includes all the complex interactions between electrons, and the electron-electron energy. DF In T, the exchange function is expressed by the one-electron potential functional (function of a function) expressed by the electron density. The calculations are highly accurate because the relevant interactions are approximated.

[0068] As shown in Table 1, the transition metals in the above composite material are manganese (Mn), which is a transition metal in Group 7; Cobalt (Co), a transition metal in group 11, copper (Cu), and silver (Ag When gold (Au) is used, the stabilization energy is negative. When an organic compound with a pair of electrons (in this case NBPhen) is mixed with a transition metal, the organic compound The fact that an object that interacts with a transition metal atom is more stable than an object that does not interact with the transition metal atom That is, from Table 1, when a transition metal and an organic compound having an unshared electron pair are mixed, When the organic compound is reacted with the transition metal, the organic compound interacts with the transition metal, and a composite material of the organic compound and the transition metal is stabilized. In addition, the HOMO and LUMO energies in Table 1 and Table 2 described later are The -levels are calculated values ​​and may differ from the measured values.

[0069] In addition, the organic compound interacts with a transition metal to form a SOMO. MO is an orbital derived from the unpaired electrons of metals, but it is also distributed in the orbitals of organic compounds. This indicates that the electron orbitals of the transition metal and the organic compound interact with each other. The SOMO levels are shown in Table 1. When using a composite material of transition metal 132, a higher SOMO level is advantageous for electron injection. Therefore, the transition metal 132 that interacts with the compound 131 is preferably an electron injecting metal. Cu and A, which have the same SOMO level as Li, are widely used materials for the layer. In one embodiment of the present invention, g, Co, and Mn can be particularly suitably used.

[0070] In addition, compound 131 interacts with the transition metal 132 to form a SOMO, which allows electron injection. An unpaired electron is formed in the layer 130. Therefore, the formation of the SOMO can be confirmed by electron spin resonance (E In addition, electron injection from the electrode 102 into the light-emitting layer 140 can be observed. To achieve this, the spin density due to the SOMO must be less than 1×10 16 spins / cm 3 More than 5×10 is preferable. 16 spins / cm 3 More preferably, 1×10 17 s pins / cm 3 The above is even more preferable.

[0071] On the other hand, when considering the manufacturing process of a light-emitting device, the EL layer of the light-emitting device, especially the electron injection layer and the cathode, are generally The electrode is often formed by vacuum deposition. It is preferable to use a material that can be vapor-deposited, that is, a material that has a low melting point. Since the melting points of the elements in the seventh and ninth groups are lower than those of the elements in the ninth and ninth groups, they are suitable for use in vacuum deposition. Among the group 11 elements, Ag is particularly preferable because it has a low melting point. This method is preferred because it allows transition metal atoms and organic compounds to be mixed easily. I wish.

[0072] Ag and Cu can also be used as cathode materials. By using the same material for 02, the light-emitting element can be easily fabricated, which is preferable. In addition, by using the same material for the electron injection layer 130 and the electrode 102, The adhesion between the injection layer 130 and the electrode 102 can be increased, improving the reliability of the light-emitting device. In addition, the manufacturing cost of the light emitting device can be reduced.

[0073] Next, when Ag is used as the transition metal 132, compound 131 is obtained, which has an unshared electron pair. The interaction between compound 131 and Ag atoms in various organic compounds The stabilization energy and SOMO level in the case of The results are shown in Table 2. The organic compounds used and their abbreviations are shown below. The calculation method is the same as that used for the calculations in Table 1.

[0074] [ka]

[0075] [Table 2]

[0076] From Table 2, various organic compounds with unshared electron pairs are mixed with transition metals (Ag in this case). In this case, the stabilization energy is negative, so the transition occurs with organic compounds that have unshared electron pairs. It is clear that metal composites are stabilized through interactions.

[0077] When compound 131 interacts with transition metal 132, the transition metal 132 acts as an electron donor. In this case, compound 131 is preferably an electron acceptor. It is preferable that the compound 131 has an electron-deficient heteroaromatic ring. Because it is easy to receive, it has a small stabilization energy when interacting with transition metal 132 atoms. In addition, compounds having an electron-deficient heteroaromatic ring have good electron transport properties. Therefore, when used in an electron injection layer, the driving voltage of a light-emitting device can be reduced. Preferred as item 131.

[0078] The electron-deficient heteroaromatic ring is preferably a nitrogen-containing heteroaromatic ring, and is preferably a pyridine ring or a diazine ring. (pyrimidine ring, pyrazine ring, pyridazine ring), or triazine ring These rings are more preferably excellent in electrochemical stability, and therefore can be used to form a highly reliable light-emitting device. In addition, since the electron transport properties are excellent, the driving voltage of the light-emitting element can be reduced. The compound having an electron-deficient heteroaromatic ring can be It may be a metal complex.

[0079] In addition, when an organic compound is used as the compound 131, the number of carbon atoms is 25 or more and 100 or less. By setting the carbon number in this range, it is possible to obtain an organic compound with excellent sublimation properties. This makes it possible to suppress the thermal decomposition of organic compounds during vacuum deposition, resulting in good material usage. Furthermore, it is preferable that the glass transition point (Tg) is 100° C. or higher. By using an organic compound having such a Tg in the EL layer, a light-emitting element having excellent heat resistance can be obtained. It can be said that:

[0080] From Tables 1 and 2, NBPhen, diquinoxalino[2,3-a:2',3'-c]phenyl HATNA (abbreviation: HATNA), 2,4,6-tris[3'-(pyridin-3-yl)biphenyl] [phenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz) is a compound that is The stabilization energy when interacting with Ag atoms is smaller than that of the compounds The heterocycles of the compound have multiple conjugated double bonds arranged in the order of NCCN. The presence of such a binding site allows the compound 131 and the transition metal 132 to interact with each other. When the two interact with each other, a chelate ring is formed (compound 131 interacts with transition metal 132, Therefore, compound 131 can be used as a transition metal 132 atom. When coordinated to a molecule, the formation of a chelate ring is preferred because the stabilization energy is reduced.

[0081] In addition, the molar ratio of the transition metal 132 to the compound 131 is preferably It is preferably 0.1 or more and 10 or less, more preferably 0.2 or more and 2 or less, and more preferably 0.2 It is more preferable that the ratio of the transition metal 132 and the compound 1 is 0.8 or less. By mixing 31, it is possible to provide a light emitting device having good electron injection properties. If the molar ratio of the transition metal 132 to the mixture 131 is smaller than the above ratio, The amount of compound 131 that interacts with the transition metal 132 to form a SOMO is small, so electron injection is difficult. In addition, if the molar ratio of the transition metal 132 is higher than the above ratio, In this case, the transmittance of the electron injection layer 130 decreases, and the light emitting efficiency of the light emitting device may decrease. be.

[0082] The thickness of the electron injection layer 130 is preferably 3 nm or more, and more preferably 5 nm or more. By adopting this composition, a composite material in which the transition metal 132 and the compound 131 are mixed is obtained. The electron injection layer 130 can function satisfactorily. Preferably, the thickness is 20 nm or less, more preferably, 10 nm or less. This reduces the effect of light absorption by the electron injection layer 130, resulting in a light-emitting element with high luminous efficiency. A child can be provided.

[0083] Next, we used iron (Fe), an even-numbered transition metal, as transition metal 132, and synthesized copper (Cu) as compound 131. Compound 131 and transition metal 13 in the case of using phthalocyanine (abbreviation: CuPc) The stabilization energy and SOMO level of the interaction between 2 and 2 are estimated by quantum chemical calculations. The results are shown in Table 3. The quantum chemical calculation method was the same as that in Table 1. The calculation method is the same as that used for the calculation of the

[0084] [Table 3]

[0085] Copper phthalocyanine has an odd number of electrons and has SO From Table 3, copper phthalocyanine is an organic compound with an unshared electron pair. When anthracene is used, it can be mixed with an even-numbered transition metal (Fe in this case) to stabilize the ene. In other words, the energy of an organic compound with an unshared electron pair and a transition metal atom is negative. It can be seen that the interaction between these two stabilizes the structure.

[0086] In addition, the interaction between copper phthalocyanine and Fe results in a complex of copper phthalocyanine and Fe. The SOMO of the material is formed. The energy level of the SOMO is the same as that of the HOM of copper phthalocyanine. The LUMO level is located between the O level and the LUMO level. Therefore, the composite material is used as the electron injection layer 130. By using such a compound, a light-emitting element having excellent electron injection properties can be provided.

[0087] <Light-emitting element configuration example 2> Next, a configuration example different from that of the light emitting element 150 shown in FIG. 1 will be described with reference to FIGS. 2(A) and 2(B). The following is an explanation of this.

[0088] FIG. 2 is a schematic cross-sectional view illustrating a light-emitting device according to one embodiment of the present invention. In B), the parts having the same functions as those in FIG. 1 are marked with the same hatch pattern. In addition, parts having similar functions are given similar reference symbols. , detailed description of which may be omitted.

[0089] The light-emitting element 152 shown in FIG. 2A has a pair of electrodes (electrode 101 and electrode 102). The EL layer 105 is disposed between the pair of electrodes. The semiconductor device further includes a buffer layer 117. The buffer layer 117 is provided between the electron injection layer 130 and the electrode 102 .

[0090] The EL layer 105 shown in FIG. 2A includes a hole injection layer 111, a positive hole injection layer 112, a positive hole injection layer 113, a positive hole injection layer 114, a positive hole injection layer 115, a positive hole injection layer 116, a positive hole injection layer 117, a positive hole injection layer 118, a positive hole injection layer 119 ... It has functional layers such as a hole transport layer 112 and an electron transport layer 118 .

[0091] By providing a buffer layer 117 between the electrode 102 and the electron transport layer 118, the electron transport The probability that the layer 118, the electron injection layer 130, the light emitting layer 140, etc. come into contact with oxygen and moisture is reduced. Therefore, it is expected that the moisture resistance and oxidation resistance of the light-emitting element will be improved.

[0092] In one embodiment of the present invention, the electron injection layer 130 is a composite material of the above-mentioned compound 131 and a transition metal 132. The buffer layer 117 is made of an organic compound having an electron-deficient heteroaromatic ring. As mentioned above, the deficient heteroaromatic ring has excellent electron transport properties, which reduces the driving voltage of the light-emitting device. It is possible.

[0093] By sandwiching the buffer layer 117 between the electron injection layer 130 and the electrode 102, the electrode 102 This is preferable because it can reduce the energy barrier between the electron injection layer 130 and the The thickness of the buffer layer is preferably 1 nm or more and 20 nm or less. It is possible to reduce the electron injection barrier while maintaining good electron transport properties.

[0094] In addition, the LUMO level of the organic compound used in the buffer layer 117 is formed in the electron injection layer 130. It is preferable that the SOMO level is lower than the SOMO level of the electron injection. This is preferable because it makes it possible to reduce the electron injection barrier between the injection layer 130 and the electrode 102 .

[0095] The composite material of the transition metal 132 and the compound 131 having an unshared electron pair is thin. More specifically, it can be used as an electron injection layer in a thin-film solar cell. It can be suitably used.

[0096] <Configuration example 3 of light-emitting element> The light-emitting element 154 shown in FIG. 2B has a pair of electrodes (electrode 101 and electrode 102). The EL layer 107 is provided between the pair of electrodes. The charge generating layer 160 is also included. 160 is provided between the electron injection layer 130 and the electrode 102 .

[0097] The EL layer 107 shown in FIG. 2B includes a hole injection layer 111, a hole injection layer 112, a light emitting layer 140, and a cathode. It has functional layers such as a hole transport layer 112 and an electron transport layer 118 .

[0098] By providing a charge generating layer 160 between the electrode 102 and the electron transport layer 118, the electron transport The amount of oxygen and moisture that penetrates into the layer 118, the electron injection layer 130, the light-emitting layer 140, etc. is reduced. This is expected to improve the moisture resistance and oxidation resistance of the light-emitting device.

[0099] As described above, when the charge generating layer 160 has a structure including a hole transporting material and an electron accepting material, In this case, the electron injection layer 130 is made of a metal having a small work function, such as an alkali metal or an alkaline earth metal. When a metal material is used, the electron-accepting property of the charge generating layer 160 can be obtained from the material used for the electron injection layer 130. Since the material extracts electrons, near the interface between the charge generation layer 160 and the electron injection layer 130 A depletion layer occurs. This can cause the driving voltage to increase. In order to suppress the depletion layer, In the present embodiment, a layer having a function of transferring electrons is provided between the electron injection layer 130 and the charge generation layer 160. It was necessary to do so.

[0100] On the other hand, in the light-emitting element of one embodiment of the present invention, the electron-injection layer 130 has a transition metal and an unshared electron pair. By using a composite material with a compound having the above-mentioned property, the charge generating layer 160 can be made to have a high electron-accepting property. Therefore, the charge generation can be prevented without generating the depletion layer. Since the layer 160 can be provided, the number of layers can be reduced, and a light-emitting element having a low driving voltage can be manufactured. Cut.

[0101] The thickness of the charge generating layer 160 is not particularly limited and can be adjusted appropriately. For example, By adjusting the film thickness from the light-emitting layer 140 to the electrode 102, The light emitted from the charge generating layer 160 can be efficiently extracted to the outside of the light emitting device. By adjusting the film thickness, the light extraction efficiency can be improved.

[0102] In addition, it is preferable that the charge generating layer 160 and the electrode 102 are provided in contact with each other. Since the electron injection barrier between the electrode 102 and the EL layer 107 can be suppressed, the driving of the light emitting element can be improved. In addition, the charge generation layer 160 and the electron injection layer 130 are in contact with each other. As described above, in one embodiment of the present invention, the charge generating layer 160 and the electron injection layer Even when the light emitting element 130 is in contact with the substrate 130, a light emitting element with a low driving voltage can be fabricated. As a result, the number of stacked EL layers 107 can be reduced.

[0103] In addition, the electron-accepting material of the charge generating layer 160 is preferably a transition metal oxide. Examples of the transition metal oxide include titanium oxide and vanadium oxide. , tantalum oxide, molybdenum oxide, tungsten oxide, rhenium oxide, ruthenium Examples of the oxides include aluminum oxide, chromium oxide, zirconium oxide, hafnium oxide, and silver oxide. In particular, molybdenum oxide is preferred because it is stable in the air, has low hygroscopicity, and is inexpensive. By using the transition metal oxide, the electron injection barrier with the electrode 102 can be reduced. Therefore, in one embodiment of the present invention, the electron injection layer 130 has a transition metal element. The charge generating layer 160 is a light emitting element having a transition metal element. The electron-accepting material contained in 0 is not limited to the above-mentioned compounds.

[0104] The charge generating layer 160 may have a hole transporting material having a pyrrole skeleton, a thiophene skeleton, or the like. It is preferable to use an organic compound containing either a furan skeleton or an aromatic amine skeleton. Since the organic compound having such a skeleton has a high hole transporting property, it is preferable to use the organic compound in the charge generating layer 160. As a result, the driving voltage of the light-emitting element can be reduced. The transport material is not limited to the above-mentioned compounds.

[0105] <Configuration Example 4 of Light-Emitting Element> Next, a light emitting element 150 shown in FIG. 1 and a light emitting element 152 and a light emitting element 154 shown in FIG. A configuration example will be described below with reference to FIG.

[0106] FIG. 49 is a schematic cross-sectional view of the light emitting element 2250a and the light emitting element 2250b.

[0107] The light emitting element 2250a and the light emitting element 2250b are formed by forming an electrode 2101 and an electrode The electrode 2102, the electrode 2103, and the electrode 2104 are also included. 102, between electrode 2102 and electrode 2103, and between electrode 2102 and electrode 210 Between at least the light-emitting unit 2106 and the light-emitting unit 2108 and the electron injection layer 2104, 130. In addition, a power supply is provided between the light emitting unit 2106 and the light emitting unit 2108. A charge generating layer 2115 is provided. The light emitting unit 2106 and the light emitting unit 2108 are , may be of the same configuration or of different configurations.

[0108] The charge generating layer 2115 sandwiched between the light emitting unit 2106 and the light emitting unit 2108 is, for example, For example, when a voltage is applied between the electrodes 2101 and 2102, electrons are generated in one of the light-emitting units. For example, in FIG. 49, A voltage is applied so that the potential of the electrode 2102 is higher than the potential of the electrode 2101. When the charge generation layer 2115 is turned on, the charge generation layer 2115 injects electrons into the light-emitting unit 2106, Holes are injected into 108 .

[0109] The light-emitting unit 2106 includes, for example, a hole injection layer 2111, a hole transport layer 2112, The light-emitting unit 2108 includes, for example, an emissive layer 2140 and an electron-transporting layer 2113. For example, a hole injection layer 2116, a hole transport layer 2117, a light emitting layer 2170, and an electron transport layer 211 18 and an electron injection layer 2119.

[0110] Here, as shown in FIG. 49, the electron injection layer 2130 is adjacent to the electron transport layer 2113 and It is preferably provided between the light-emitting unit 2108 and the electron transport layer 2113. The generating layer 2115 is adjacent to the electron injection layer 2130 and is in contact with the light-emitting unit 2115. It is preferable that the light emitting unit 2108 is provided between the light emitting unit 2108 and the light emitting unit 2109. 106.

[0111] In the example of the configuration of the light-emitting element, the electrodes 2101, 2103, and 2104 are The electrode 2102 will be described as an anode and the electrode 2103 as a cathode. The configuration of 250b is not limited to this. The electrode 2104 is a cathode, the electrode 2102 is an anode, and the layers between the electrodes are stacked in the reverse order. That is, the light-emitting unit 2106 may be formed by stacking the hole injection layer 211 from the anode side. 1, a hole transport layer 2112, a light emitting layer 2140, an electron transport layer 2113, and an electron injection layer 2114. The light-emitting unit 2108 is formed by stacking the layers 130 and 130 in the order shown in FIG. a light-emitting layer 2116, a hole-transporting layer 2117, a light-emitting layer 2170, an electron-transporting layer 2118, and The child injection layer 2119 may be laminated in this order.

[0112] The light emitting element 2250a and the light emitting element 2250b may have the structure shown in FIG. At least the light-emitting layer 2140, the light-emitting layer 2170, the charge generating layer 2115, and The electron injection layer 2130 is provided, and the hole injection layer 2111, the hole injection layer 2116, and the hole transport layer 21 12, hole transport layer 2117, electron transport layer 2113, electron transport layer 2118, electron injection layer 21 Each of the 19 may or may not have each of them.

[0113] Furthermore, a layer may be formed between the pair of electrodes according to its function, and is not limited thereto. That is, between the pair of electrodes, a hole or electron injection barrier is provided to reduce the hole or electron injection barrier. Improve transportability, inhibit hole or electron transportability, or suppress quenching by electrodes The structure may include a layer having a function of controlling or enabling the same.

[0114] In the case of the light-emitting unit 2108, the surface of the light-emitting unit on the anode side is the charge generating layer 211. When the charge generating layer 2115 is in contact with the light emitting unit 2108, the charge generating layer 2115 functions as a hole injection layer for the light emitting unit 2108. Since the light-emitting unit may also have a hole injection layer, the light-emitting unit may not need to have a hole injection layer. There are cases.

[0115] In addition, in FIG. 49, a light emitting element having two light emitting units has been described. The same can be applied to a light-emitting element in which three or more light-emitting units are stacked. As shown in the light-emitting element 2250a and the light-emitting element 2250b, a plurality of light-emitting elements are disposed between a pair of electrodes. By separating the light units with charge generating layers, high brightness can be achieved while keeping the current density low. It is possible to realize a light-emitting element that can emit light and has a long life. It is possible to achieve this.

[0116] In the light-emitting element 2250a, the electrodes 2101, 2103, and 2104 are The electrode 2102 has a function of reflecting visible light, and the electrode 2103 has a function of transmitting visible light. In the optical element 2250b, the electrodes 2101, 2103, and 2104 are The electrode 2102 has a function of transmitting visible light, and the electrode 2102 has a function of reflecting visible light.

[0117] Therefore, the light emitted by the light-emitting element 2250a is emitted to the outside through the electrode 2102. Light emitted by the light emitting element 2250b passes through the electrodes 2101, 2103, and 2104. However, one embodiment of the present invention is not limited thereto. Alternatively, the light emitting element may extract light both above and below the substrate 2200.

[0118] The electrode 2101 includes a conductive layer 2101a and a conductive layer 2101b in contact with the conductive layer 2101a. The electrode 2103 includes a conductive layer 2103a and a conductive layer 2103b. The electrode 2104 includes a conductive layer 2104a and a conductive layer 2103b. and a conductive layer 2104b in contact with the upper surface of 2104a.

[0119] The conductive layer 2101b, the conductive layer 2103b, and the conductive layer 2104b have a function of transmitting visible light. In addition, in the light-emitting element 2250a, the conductive layer 2101a, the conductive layer 2103a, The conductive layer 2104a has a function of reflecting visible light. In the above, the conductive layer 2101a, the conductive layer 2103a, and the conductive layer 2104a transmit visible light. It has the function of

[0120] A light emitting element 2250a shown in FIG. 49(A) and a light emitting element 2250b shown in FIG. 49(B) 2101 and 2102, and the area 2222B sandwiched between the electrodes 2101 and 2102, and the area 2222B sandwiched between the electrodes 2102 and 2102 103 and the region 2222G sandwiched between the electrode 2102 and the electrode 2104 A partition 2145 is provided between the regions 2222R and 2222R. The partition 2145 has insulating properties. Wall 2145 covers the ends of electrodes 2101, 2103, and 2104. By providing the partition wall 2145, the substrate 2200 in each region has an overlapping opening. It is possible to separate each of the electrodes into islands.

[0121] In FIG. 49, the hole injection layer 2111, the hole injection layer 2116, the hole transport layer 21 12, hole transport layer 2117, light emitting layer 2140, light emitting layer 2170, electron transport layer 2113, The electron transport layer 2118, the electron injection layer 2119, the charge generation layer 2115, and the electrode 2102 are each Although the example shows a common arrangement without being separated in each region, They may be provided separately.

[0122] In the light-emitting element 2250a and the light-emitting element 2250b according to one embodiment of the present invention, the region 222 Between the pair of electrodes (electrode 2101 and electrode 2102) in region 2222B, and between the pair of electrodes ( Between the pair of electrodes (electrodes 2102 and 2103) in the region 2222R, By applying a voltage between the cathode and the electrode 2104, electrons are injected from the cathode to the electron injection layer 2. 119, and holes are injected from the anode into the hole injection layer 2111, Also, electrons are injected from the charge generation layer 2115 into the electron injection layer 2130, and a charge Holes are injected from the generating layer 2115 into the hole injection layer 2116. The recombination of the trapped carriers (electrons and holes) forms excitons. In the light-emitting layer 2140 and the light-emitting layer 2170 having the material, carriers (electrons and holes) are regenerated. When the electrons combine and an exciton is formed, the light-emitting materials in the light-emitting layers 2140 and 2170 This results in an excited state, and light is emitted from the light-emitting material.

[0123] The light-emitting layer 2140 and the light-emitting layer 2170 may be purple, blue, blue-green, green, yellow-green, yellow, or yellow. Any one or more selected from the group consisting of luminescent materials that emit orange, orange, or red light It is preferable that the compound has the following structure:

[0124] The light-emitting layer 2140 and the light-emitting layer 2170 may be configured as a stack of two layers. The light-emitting layer of the layer is made of a first compound and a second compound, which have the function of exhibiting different colors. By using different types of luminescent materials, multiple lights can be emitted simultaneously. The light emitted by the optical layer 2140 and the light emitting layer 2170 is white or a color close to white. It is preferable to select the light-emitting material used for each light-emitting layer in such a manner that the light-emitting material is uniform.

[0125] The light-emitting layer 2140 and the light-emitting layer 2170 may have a structure in which three or more layers are laminated. However, layers that do not contain light-emitting materials may also be included.

[0126] In addition, the light emitting element 2250a and the light emitting element 2250b are arranged in the regions 2222B and 2222 222G, and the light emitted from the region 2222R is extracted from the optical element 222 4B, optical element 2224G, and optical element 2224R. The light emitted from the region is emitted to the outside of the light emitting element through each optical element. The light emitted from 2222B is emitted through optical element 2224B and is reflected from region 2222G. The light emitted from the region 2222R is emitted through the optical element 2224G. is emitted through optical element 2224R.

[0127] In addition, the optical elements 2224B, 2224G, and 2224R receive incident light. The optical element 22 has a function of selectively transmitting light of a specific color from the light that is received. The light emitted from the region 2222B through the region 24B is blue light. The light emitted from the region 2222G via the optical element 2224G is green light. The light emitted from the region 2222R via the optical element 2224R is red. It becomes a light that exhibits the following.

[0128] In addition, in FIG. 49(A)(B), the light emitted from each region through each optical element is Blue (B) light, green (G) light, and red (R) light, respectively. The light emitting element 2250a shown in FIG. The light-emitting element 2250b shown in FIG. 49(B) is a bottom emitter. It is a cushion type light emitting element.

[0129] In addition, a light-shielding layer 2223 is provided between each optical element. It should be noted that the light shielding layer 2223 is not provided. In addition, the optical element 2224B, the optical element 2224G, or the optical element 2224R Any one or more of the optical elements 2224B and 2224C may be omitted. By not providing the element 2224G or the optical element 2224R, the light emitted from the light emitting element Therefore, the light extraction efficiency can be improved.

[0130] The charge generating layer 2115 is made of a material having a hole transporting property and an electron acceptor. or electron-transporting materials to which electron donors (donors) have been added. , can be formed.

[0131] In order to reduce the driving voltage of the light-emitting element, the charge generating layer 2115 to the electron transport layer The electron injection barrier to the charge generation layer 2113 is reduced, and the electrons generated in the charge generation layer 2115 are transported to the electron transport layer It is preferable that the charge generation layer 211 be configured to smoothly inject and transport the charge into the charge generation layer 2113. It is preferable to provide an electron injection layer 2130 between the electron transport layer 2113 and the electron injection layer 2115. Since the layer 2119 and the electron injection layer 2130 are required to have high electron injection properties, Alkali metals such as lithium (Li) and cesium (Cs) and their compounds, calcium Alkaline earth metals such as Ca (Ca) and their compounds are used. When this compound is used in the electron injection layer 2130, for example, as shown in FIG. When a voltage is applied between the electrode 2102 and the region 2222G to pass a current through the region 2222G, the electron injection layer 21 30 and the electron transport layer 2113, the region 2222B and the region 2222G adjacent thereto. A current also flows through the region 2222R, and not only does the region 2222G emit light, but the adjacent region A phenomenon called crosstalk occurs in which light is emitted from the regions 2222B and 2222R. In FIG. 50, the area 2222G, the area 2222R, and the area 2222G may be The current flowing through 2B is represented by a solid arrow.

[0132] When crosstalk occurs in the light-emitting element in this way, the desired region (e.g., region 2222 G), as well as other regions (e.g., regions 2222B and 2222R). Since light is emitted from the light emitting element 2250a and the light emitting element 2250b, The color purity and the emission intensity may decrease.

[0133] The crosstalk occurs when the electron injection layer 2115 and the electron transport layer 2113 are sandwiched between the electron generation layer 2115 and the electron transport layer 2113. The alkali metal, alkaline earth metal, or compound thereof used in 130 is an electron transport layer 2 The conductivity of the electron transport layer 2113 (especially the conductivity in the direction perpendicular to the voltage application direction) is increased. One of the reasons for this is that the electrical conductivity of the material is improved. When these compounds are used in the electron injection layer 2130, the metal with the small atomic number becomes an electron transporter. Therefore, in order to suppress crosstalk, the electron injection It is preferred that layer 2130 be free of alkali metals and alkaline earth metals. The implant layer 2130 does not include alkali metals, alkaline earth metals, or compounds thereof. In this case, the barrier for electron injection from the charge generating layer 2115 to the electron transport layer 2113 becomes high, so that the electron This makes it difficult for electrons to be injected into the electron transport layer 2113, which may increase the driving voltage of the light-emitting element or The light efficiency may decrease.

[0134] Therefore, the driving voltage of the light emitting element can be reduced, the light emitting efficiency can be improved, and crosstalk can be suppressed. In order to achieve this, it is necessary to use a metal that has excellent electron injection properties and is difficult to diffuse for the electron injection layer 2130. As a metal that is difficult to diffuse and is used for the electron injection layer 2130, gold having a large atomic radius is preferable. Metals with large atomic weights are also preferred.

[0135] On the other hand, metals with large atomic radii or large atomic weights are difficult to diffuse, but they are difficult to disperse in the electron injection layer 2. When used in the present invention, the charge generating layer 2115 and the electron transport layer 2113 form an electron injection barrier between the charge generating layer 2115 and the electron transport layer 2113. As a result, the driving voltage of the light emitting element may become high and the light emitting efficiency may decrease.

[0136] Here, the present inventors have discovered a compound having a SOMO-forming combination with a transition metal. The material may be used in the electron injection layer 2130 adjacent to the charge generation layer 2115 to provide electron injection properties. It has been found that a light emitting device having excellent light emission and suppressed crosstalk can be obtained.

[0137] Therefore, the light-emitting element of one embodiment of the present invention has a plurality of light-emitting units. A composite material of an organic compound having a shared electron pair and a transition metal is placed between the light-emitting unit. This is a light emitting element used in the injection layer 2130.

[0138] Transition metals have large atomic weights and are less likely to diffuse in organic compounds, so crosstalk is suppressed. A light emitting element can be provided.

[0139] In addition, the organic compound having the unshared electron pair is responsible for transporting electrons, and therefore is required to have at least a π-conjugated In this case, an atom having a π electron (Pz orbital) is preferably Atoms that have pairs or are bonded to (adjacent to) atoms that have π electrons (Pz orbitals) It is preferable that the unshared electron pair is present.

[0140] Here, the composite material of the transition metal 132 and the compound 131 shown in FIG. 1 is used for the electron injection layer 2130. When the HOMO level of compound 131 interacts with the transition metal atom 132, is preferably the same as the HOMO level of the original compound 131. When using an organic compound with electron transport function, the HOMO approximation of compound 131 is Therefore, compound 131 and transition metal 13 The HOMO level formed by the interaction of 2 is the same as that of the original compound 131. etc., the hole injection barrier between the electron injection layer 2130 and the charge generation layer 2115 is large. Therefore, holes are less likely to escape from the electron injection layer 2130 to the charge generation layer 2115, and This is preferable because it can improve the carrier balance.

[0141] In addition, when the above-mentioned composite material is used for the electron injection layer 2119 and the electron injection layer 2130, SO Since MO is an orbital having only one electron, light emitting element 2250a and light emitting element 2250 When a voltage is applied to b, the electrons in the SOMO become carriers in the light-emitting device, and the electron transport layer 21 13 and the light-emitting layer 2140. Also, the electrons are transported from the charge generating layer 2115 to the electron injection layer 21 In other words, the electron injection layer 2130 is a SOMO. By having a combination of materials that form Electrons can be easily injected into compound 06. Also, the SOMO level is Therefore, the LUMO level of compound 131 is high. Specifically, the LUMO level of the compound 131 is preferably −3.6 eV or higher and −2.3 eV or lower. It is preferable that the LUMO level is 5 or less. Then, the SOMO level formed by the interaction becomes a level suitable for electron injection, The electron injection barrier between the electron injection layer 2130 and the charge generation layer 2115 can be reduced.

[0142] Compound 131 and transition metal 132 interact to form SOMO, which allows the electron injection layer 13 An unpaired electron is formed at 0. Therefore, the formation of SOMO can be observed by ESR. In order to improve the electron injection from the charge generating layer 2115 to the light emitting layer 2140, , the spin density due to SOMO is 1×10 16 spins / cm 3 The above is preferable, 5×10 16 spins / cm 3 More preferably, 1×10 17 spins / cm 3 The above is more preferable. In order to suppress crosstalk, the shift caused by SOMO is Pin density is 5 x 10 17 spins / cm 3 The following is preferred:

[0143] <Components of light-emitting element> Next, the components of the light-emitting element shown in FIGS. 1, 2, 49, and 50 will be described in detail below. Provide an explanation.

[0144] ≪Electron injection layer≫ The electron injection layer 130, the electron injection layer 2130, and the electron injection layer 2119 have a high electron injection property. The layer is preferably a composite material of the above-mentioned transition metal and an organic compound having an unshared electron pair. In addition, the electron injection layer 130, the electron injection layer 2130 and the electron injection layer The organic compound used in 2119 is preferably a material with excellent electron transport properties. Specifically, for example, the following metal complexes and heteroaromatic compounds can be used.

[0145] The electron injection layer 130, the electron injection layer 2130, and the electron injection layer 2119 each contain a quinoline ligand. , benzoquinoline, oxazole, or thiazole ligands Complexes, pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, triazine derivatives, oxazine Examples of the diazole derivatives include diazole derivatives, triazole derivatives, and phenanthroline derivatives. Specifically, Alq3, Almq3, BeBq2, BAlq, bis(8-quinolinolato)thio Lead(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc (II) (abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phenolato]zinc (II) (abbreviation: ZnBTZ) and other metal complexes can be used. Biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazo PBD, 1,3-bis[5-(p-tert-butylphenyl)-1,3, 4-Oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-furan phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole ( Abbreviation: CO11), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-bu 3-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 4-(4-ethylphenyl)-5-(4-biphenylyl)-1,2,4 -Triazole (abbreviation: p-EtTAZ), 4,4'-bis(5-methylbenzoxazo 2,2',2''-(1,3,5-phenyl-2-yl)stilbene (abbreviation: BzOs), 1-phenyl-1H-benzimidazole (TPBI) ), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzyl Heterocyclization of azole skeleton such as benzimidazole (abbreviation: mDBTBIm-II) Compounds such as 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]ky Noxalin (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophene- 4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBT BPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3- yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3 ,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quino Xaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophene-4-yl) 7mDBTPDBq-II and 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quino Xaline (abbreviation: 6mDBTPDBq-II), 4,6-bis[3-(phenanthrene- 9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3- (4-Dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II ), 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation : 4,6mCzP2Pm), 4-{3-[3'-(9H-carbazol-9-yl)]biphenyl Phenyl-3-yl}benzofuro[3,2-d]pyrimidine (abbreviation: 4mCzBPBfp Heterocyclic compounds with diazine skeletons such as 2-{4-[3-(N-phenyl-9 H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6- Diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2,4,6-tris [3'-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation Name: TmPPyTz), 2,4,6-tris(2-pyridyl)-1,3,5-triazinyl Heterocyclic compounds with triazine skeletons such as 2Py3Tzn (abbreviation: 2Py3Tzn) and 3,5-bis(3,5-diphenylphosphine) 35DCzPP y), 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyP B), Bathocuproine (abbreviation: BCP), 2,9-bis(naphthalene-2-yl)-4 , 7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen) and other pyridines Among the above, heterocyclic compounds having a diazine skeleton and a triazine skeleton are preferred. Heterocyclic compounds having a pyridine skeleton and heterocyclic compounds having a pyridine skeleton have good reliability. In particular, compounds having a diazine (pyrimidine or pyrazine) skeleton and a triazine skeleton are preferred. The heterocyclic compounds have high electron transport properties and contribute to reducing the driving voltage. 1×10 -6 cm 2 / Vs or more. Any other substance having a high electron transporting property may be used for the electron injection layer 130 and the electron injection layer 213. 0 and the electron injection layer 2119.

[0146] <Hole injection layer> The hole injection layer 111 and the hole injection layer 2111 are one of a pair of electrodes (electrode 101 or electrode The hole injection layer 2116 from the electrode 102, electrode 2101 or electrode 2102 is a charge generating layer. It has the function of promoting hole injection by reducing the hole injection barrier from 2115. For example, the material may be a transition metal oxide, a phthalocyanine derivative, or an aromatic amine. Examples of transition metal oxides include molybdenum oxide, vanadium oxide, and ruthenium oxide. , tungsten oxide, manganese oxide, etc. Phthalocyanine derivatives include Examples of the aromatic amine include phthalocyanine and metal phthalocyanine. Examples include phenylenediamine derivatives and polythiophenes. Polymers such as phosphorus can also be used, for example self-doped polythiophene. Poly(ethylenedioxythiophene) / poly(styrenesulfonic acid) are representative examples. Here is an example.

[0147] The hole injection layer 111, the hole injection layer 2111, and the hole injection layer 2116 are made of a hole transport material. Alternatively, a layer having a composite material of a material and a material exhibiting electron accepting properties thereto may be used. Alternatively, a laminate of a layer containing a material exhibiting electron accepting properties and a layer containing a material having hole transporting properties may be used. Charge can be exchanged between these materials in a steady state or in the presence of an electric field. Materials that exhibit electron-accepting properties include quinodimethane derivatives, chloranil derivatives, and hexaazane. Examples of organic acceptors include triphenylene derivatives. 7,8,8-Tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4 -TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5, Electron-withdrawing groups (halo groups) such as 8,9,12-hexaazatriphenylene (abbreviation: HAT-CN) In addition, transition metal oxides, such as those of Group 4 to Oxides of group 8 metals can be used. Specifically, vanadium oxide, niobium oxide, oxide Tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, rhodium oxide Among them, molybdenum oxide is stable in the air, has low hygroscopicity, and is easy to handle. It is preferable because it is easy to use.

[0148] As the hole transporting material, a material having a higher hole transporting property than an electron transporting property can be used. ×10 -6 cm 2 It is preferable that the material has a hole mobility of 1 / Vs or more. The aromatic amines and carbenes mentioned as examples of hole transport materials that can be used in the light-emitting layer 140 are Bazole derivatives, aromatic hydrocarbons, stilbene derivatives, etc. can be used. The hole transporting material may be a polymer compound.

[0149] Other examples of hole transport materials include aromatic hydrocarbons, such as 2-tert -Butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 2- tert-Butyl-9,10-di(1-naphthyl)anthracene, 9,10-bis(3, 5-Diphenylphenyl)anthracene (abbreviation: DPPA), 2-tert-butyl-9 ,10-Bis(4-phenylphenyl)anthracene (abbreviation: t-BuDBA), 9,1 0-Di(2-naphthyl)anthracene (abbreviation: DNA), 9,10-diphenylanthracene 2-tert-butylanthracene (abbreviation: DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAn th), 9,10-bis(4-methyl-1-naphthyl)anthracene (abbreviation: DMNA) , 2-tert-butyl-9,10-bis[2-(1-naphthyl)phenyl]anthracene 9,10-bis[2-(1-naphthyl)phenyl]anthracene, 2,3,6,7- Tetramethyl-9,10-di(1-naphthyl)anthracene, 2,3,6,7-tetramethyl 9,10-di(2-naphthyl)anthracene, 9,9'-bianthryl, 10,1 0'-Diphenyl-9,9'-bianthryl, 10,10'-bis(2-phenylphenyl) 10,10'-bis[(2,3,4,5,6-pentafluorophenyl) phenyl)phenyl]-9,9'-bianthryl, anthracene, tetracene, rubrene, perylene, 2,5,8,11-tetra(tert-butyl)perylene, etc. In addition, pentacene, coronene, etc. can also be used. -6 cm 2 / Vs or more, and an aromatic hydrocarbon having 14 to 42 carbon atoms. It is more preferable to use

[0150] 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.

[0151] Also, 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]fluor phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), 4,4',4''-(phenyl) (1,3,5-phenyl-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), 1,3,5-Tri(dibenzothiophen-4-yl)benzene (abbreviation: DBT3P-II ), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)fluor 4-[4-(9-phenyl)dibenzothiophene (abbreviation: DBTFLP-III), [6-phenyl-9H-fluoren-9-yl]phenyldibenzothiophene (abbreviation :DBTFLP-IV), 4-[3-(triphenylen-2-yl)phenyl]dibenzo Thiophene compounds such as thiophene (abbreviation: mDBTPTp-II), furan compounds, An orene compound, a triphenylene compound, a phenanthrene compound, etc. can be used. Among the above-mentioned compounds, pyrrole skeleton, furan skeleton, thiophene skeleton, aromatic amine skeleton, Compounds having this structure are stable and reliable, and are therefore preferred. The material has a high hole transporting property and contributes to reducing the driving voltage.

[0152] <Hole transport layer> The hole transport layer 112, the hole transport layer 2112, and the hole transport layer 2117 contain a hole transport material. The hole injection layers 111, 2111 and 2116 are made of the same material. The hole transport layer 112, the hole transport layer 2112 and the hole transport layer 2112 may be used. 117 are holes injected from the hole injection layer 111, the hole injection layer 2111, and the hole injection layer 2116, respectively. The hole transport layer 140 has a function of transporting the injected holes to the light emitting layer 2140 and the light emitting layer 2170. do.

[0153] At this time, the LUMO level of the acceptor material of the hole injection layer 111 and the LUMO level of the light emitting layer 14 A hole transporting material having a HOMO level between the HOMO level of the material having 0 and the HOMO level of the material having 1 is called a hole transporting material. It is preferable to use it for the transport layer 112. Similarly, the acceptor of the hole injection layer 2111 between the LUMO level of the material and the HOMO level of the material of the light-emitting layer 2140 It is preferable to use a hole transporting material having an O level for the hole transporting layer 2112. The hole transport layer 112, the hole transport layer 2112, and the hole transport layer 2117 may be a single layer or a bilayer. In this case, the hole injection layer 111 side to the light emitting layer 140 side, the hole injection layer From the hole injection layer 2111 side to the light emitting layer 2140 side, and from the hole injection layer 2116 side to the light emitting layer 2170 side, It is preferable to stack the hole transporting materials in order of decreasing MO level. 2. When the hole transport layer 2112 and the hole transport layer 2117 are laminated in two or more layers, the hole transport layer 2112 and the hole transport layer 2117 can be smoothly transported. In order to transport the hole, the difference in the HOMO levels of the hole transport materials used is preferably 0e V or more and 0.5 eV or less, more preferably 0 eV or more and 0.3 eV or less, more preferably 0 e V or more and 0.2 eV or less.

[0154] Examples of materials having hole transport properties include 4,4'-bis[N-(1-naphthyl)- N-phenylamino]biphenyl (abbreviation: NPB), 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: BSPB), 4-phenyl-4'-(9-phenyl Fluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3 '-(9-Phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP) ), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenyl PCBA1BP, 4,4'-diphenyl-4''-(9-phenyl- 9H-Carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4- (1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenyl PCBANB, 4,4'-di(1-naphthyl)-4''-(9-phenyl) PCBNBB, 9H-carbazol-3-yl)triphenylamine ,9-Dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3- yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[ 4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9'-bi Compounds with an aromatic amine skeleton, such as fluorene-2-amine (PCBASF) 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N- Carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl) 3,3'-bis(9-phenyl- 9H-carbazole (abbreviation: PCCP) and other compounds with a carbazole skeleton, ,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene)(abbreviation Name: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-ful oren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4 -[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzyl Compounds with a thiophene skeleton, such as dibenzothiophene (abbreviation: DBTFLP-IV), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation :DBF3P-II), 4-{3-[3-(9-phenyl-9H-fluoren-9-yl )phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II) Among the above, compounds having an aromatic amine skeleton are preferred. Compounds having a carbazole skeleton have good reliability and high hole transport properties. This is also preferable because it contributes to reducing the driving voltage. Among these substances, a hole transporting material may be used.

[0155] Furthermore, as a material with high hole transport properties, for example, 3-[4-(1-naphthyl)-phenyl PCPN, 3-[4-(9-phenanyl)-9-phenyl-9H-carbazole PCPPn), 4 -Phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine PCBA1BP, 4,4'-di(1-naphthyl)-4''-(9-phenyl -9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), 4- Phenyldiphenyl-(9-phenyl-9H-carbazol-3-yl)amine (abbreviation: P CA1BP), 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP ), N-[4-(9H-carbazol-9-yl)phenyl]-N-(4-phenyl)phenyl Phenylaniline (abbreviation: YGA1BP), 1,3,5-tri(dibenzothiophene-4- yl)-benzene (abbreviation: DBT3P-II), 4,4',4''-(benzene-1,3 ,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), 4-phenyl- 4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP) ), 4-[3-(triphenylene-2-yl)phenyl]dibenzothiophene (abbreviation: m DBTPTp-II), 4,4'-bis[N-(1-naphthyl)-N-phenylamino] Biphenyl (abbreviation: NPB or α-NPD) and N,N'-bis(3-methylphenyl) -N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TP D), 4,4',4''-tris(carbazol-9-yl)triphenylamine (abbreviation TCTA), 4,4',4''-tris(N,N-diphenylamino)triphenyla MIN (abbreviation: TDATA), 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( Compounds with aromatic amine skeletons such as 3-[N-(9-phenylcarbamoyl)phenyl]- carbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: P CzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenyl] phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N-(1 -naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazol Other examples include 4,4'-di(N-carbazole) and 4,4'-di(N-carbazole). 1,3,5-Tris[4-(N-carbazolyl)biphenyl (abbreviation: CBP), Carbazole compounds such as phenyl]benzene (TCPB), amine compounds, diphenyl Thiophene compounds, dibenzofuran compounds, fluorene compounds, triphenylene compounds The substances listed here are mainly 1×10 -6 cm 2 / Vs or higher. However, the transport of holes is higher than that of electrons. Other substances may be used as long as they have high resistance.

[0156] In addition, the compounds usable for the hole transport layer can be used as the hole injection layer. is also good.

[0157] <Charge generation layer> The charge generating layer 160 and the charge generating layer 2115 are formed by disposing an acyl group which is an electron acceptor to a hole transport material. Even in the case where a scepter-like substance is added, the electron transport material contains a donor that is an electron donor. The structure may be one in which a viscoelastic material is added. Also, both of these structures may be laminated. good.

[0158] The charge generating layer 160 and the charge generating layer 2115 are formed of a composite of an organic compound and an acceptor material. When a material is included, the composite material includes the composite material that can be used for the hole injection layer 111 described above. The organic compounds include aromatic amine compounds, carbazole compounds, Aromatic hydrocarbons, polymer compounds (oligomers, dendrimers, polymers, etc.), etc. As the organic compound, a compound having a hole mobility of 1×10 -6 c m 2 It is preferable to use a material with a Vs of 100 / Vs or more. However, it is preferable to use a material with a Vs of 100 / Vs or more that transports holes rather than electrons. Other substances may be used as long as they have a high acceptor property. The composite material has excellent carrier injection and transport properties, making it suitable for low-voltage operation and low-current operation. In addition, the surface of the light-emitting unit on the anode side is the charge generating layer 160 and When the charge generating layer 160 and the charge generating layer 2115 are in contact with each other, the charge generating layer 160 and the charge generating layer 2115 Since it can also play the role of a hole injection layer or a hole transport layer of the light-emitting unit, The knit may have no hole injection layer or hole transport layer.

[0159] The charge generating layer 160 and the charge generating layer 2115 are made of an organic compound and an acceptor material. The laminated structure is formed by combining layers containing the composite material and layers made of other materials. For example, a layer including a composite material of an organic compound and an acceptor substance and a layer including an electron donor A compound selected from the above substances is combined with a layer containing a compound having high electron transport properties. Also, a layer including a composite material of an organic compound and an acceptor substance and a transparent conductive layer may be formed. The conductive layer may be formed in combination with a layer including a conductive film.

[0160] From the viewpoint of light extraction efficiency, the charge generating layer 160 and the charge generating layer 2115 are preferably made of a material that is resistant to visible light. Specifically, the charge generating layer 160 and the charge generating layer 2115 are transparent to visible light. It is preferable that the charge generating layer 160 and the charge generating layer 2115 is a pair of electrodes (electrode 2101, electrode 2102, electrode 2103, and electrode 210 4) It works even with a lower conductivity than that of

[0161] The charge generating layer 160 and the charge generating layer 2115 are formed using the above-mentioned materials. In this case, an increase in driving voltage when light-emitting layers are stacked can be suppressed.

[0162] <Light-emitting layer> The light-emitting layer 140, the light-emitting layer 2140, and the light-emitting layer 2170 are purple, blue, blue-green, green, yellow, A light-emitting material having a function of exhibiting at least one of green, yellow, orange, and red light emission. In addition, the light-emitting layer 140, the light-emitting layer 2140, and the light-emitting layer 2170 each contain a light-emitting material. The host material includes one or both of an electron transporting material and a hole transporting material. will be done.

[0163] In addition, as light-emitting materials, there are light-emitting substances that can convert singlet excitation energy into light emission and triplet excitation substances that can convert singlet excitation energy into light emission. A luminescent material capable of converting excitation energy into luminescence can be used. The active substances include the following:

[0164] Luminescent substances that can convert singlet excitation energy into light emission include fluorescent substances (fluorescent The fluorescent compound is not particularly limited, but may be an anthracene derivative. Conductors, tetracene derivatives, chrysene derivatives, phenanthrene derivatives, pyrene derivatives, peri ene derivatives, stilbene derivatives, acridone derivatives, coumarin derivatives, phenoxazine derivatives Conductors, phenothiazine derivatives, etc. are preferred, and for example, the following substances can be used.

[0165] Specifically, 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2 ,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl -9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2 BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoro 1,6-Pyrene-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn) , N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H -fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMem FLPAPrn), N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl )phenyl]-N,N'-bis(4-tert-butylphenyl)-pyrene-1,6-di Amine (abbreviation: 1,6tBu-FLPAPrn), N,N'-diphenyl-N,N'-biphenyl 4-(9-phenyl-9H-fluoren-9-yl)phenyl]-3,8-dicyclo[4-(9-phenyl-9H-fluoren-9-yl)phenyl] Hexylpyrene-1,6-diamine (abbreviation: ch-1,6FLPAPrn), N,N'- (Pyrene-1,6-diyl)bis[(6,N-diphenylbenzo[b]naphtho[1,2- d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), N,N'-bis[ 4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene 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-anthryl) )triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(1 0-Phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), Perylene, 2,5,8,11-Tetra(tert-butyl)perylene (abbreviation Name: 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: DPABPA ), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl N-[4-(9,1 0-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-2,7,10,1 5-Tetraamine (abbreviation: DBC1), Coumarin 30, N-(9,10-diphenyl-2 -anthryl)-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PC APA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthryl ]-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPhA) , 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 -N-[4-(9H-carbazol-9-yl)phenyl]-N-phenyl 2-Anthracenamine (abbreviation: 2YGABPhA), N,N,9-triphenylamine Diphenyl ether-9-amine (abbreviation: DPhAPhA), Coumarin 6, Coumarin 545T, N ,N'-Diphenylquinacridone (abbreviation: DPQd), Rubrene, 2,8-di-tert -Butyl-5,11-bis(4-tert-butylphenyl)-6,12-diphenyl Thracene (abbreviation: TBRb), Nile Red, 5,12-bis(1,1'-biphenyl- 4-yl)-6,11-diphenyltetracene (abbreviation: BPT), 2-(2-{2-[4 -(Dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-ylidene ) propanedinitrile (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3,6 ,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-methylphenyl) phenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: pm PhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl- 2,3,6,7-Tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl) Thenyl]-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]-4 H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2,6- Bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methan 1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzyl 4H-pyran-4-ylidene)propane BisDCJTM, 5,10,15,20-tetraphenylbis Benzo[5,6]indeno[1,2,3-cd:1',2',3'-lm]perylene, etc. Some examples include:

[0166] In addition, examples of luminescent substances that can convert triplet excitation energy into luminescence include phosphorescent substances. Phosphorescent compounds include iridium, rhodium, Porphyrins, platinum-based organometallic complexes, and metal complexes are also examples. Examples of such complexes include platinum complexes and organic iridium complexes having ligands, and among these, organic iridium complexes and For example, iridium orthometal complexes are preferred. H-triazole ligand, 1H-triazole ligand, imidazole ligand, pyridine ligand Ligands include pyrimidine ligands, pyrazine ligands, and isoquinoline ligands. In this case, the phosphorescent compound is a triplet MLCT (Metal to Ligand Ch) It has an absorption band of the Arrhenius Array Transfer transition.

[0167] Examples of substances having a blue or green emission peak include tris{2-[5-(2 -methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazo 3-yl-κN 2 ]phenyl-κC}iridium(III) (abbreviation: Ir(mpp tz-dmp)3), tris(5-methyl-3,4-diphenyl-4H-1,2,4-tris( riazolate)iridium(III) (abbreviation: Ir(Mptz)3), tris[4-(3- Biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]i Iridium(III) (abbreviation: Ir(iPrptz-3b)3), tris[3-(5-biphenyl] (phenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]irid Ir(III) (abbreviation: Ir(iPr5btz)3), a 4H-triazole skeleton and organometallic iridium complexes having tris[3-methyl-1-(2-methylphenyl) -5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: Ir (Mptz1-mp)3), tris(1-methyl-5-phenyl-3-propyl-1H- 1,2,4-Triazolate)iridium(III) (abbreviation: Ir(Prptz1-Me) 3) and fac-triazole-based organometallic iridium complexes. S[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole] Iridium(III) (abbreviation: Ir(iPrpmi)3), tris[3-(2,6-dimethyl phenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(I II) Imidazole skeleton-containing compounds such as Ir(dmpimpt-Me)3 Organic metal iridium complexes and bis[2-(4',6'-difluorophenyl)pyridinato N,C 2’ ]Iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation: FI r6), Bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ]Ili Dium(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis (Trifluoromethyl)phenyl]pyridinato-N,C 2’}Iridium(III) pico Ir(CF3ppy)2(pic) (fluorophenyl)pyridinato-N,C 2’ ]Iridium(III) acetylacetonate (abbreviation: FIr(acac)) Among the above, 4H-triazole is an organometallic iridium complex. Nitrogen-containing five-membered heterocyclic skeletons such as 1H-triazole skeleton and imidazole skeleton The organometallic iridium complex has high triplet excitation energy and is highly reliable and has excellent luminescence efficiency. It is particularly preferred because it is also excellent in

[0168] In addition, examples of substances having a green or yellow emission peak include tris(4-methylphenyl) Ir(mppm)3, Tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: I r(tBuppm)3), (acetylacetonato)bis(6-methyl-4-phenylpyridine Iridium(III) (abbreviation: Ir(mppm)2(acac)), (acetylacetonate ruacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium( III) (abbreviation: Ir(tBuppm)2(acac)), (acetylacetonato)bis [4-(2-norbornyl)-6-phenylpyrimidinato]iridium(III) (abbreviation Ir(nbppm)2(acac)), (acetylacetonato)bis[5-methyl-6 -(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: Ir(mpmppm)2(acac)), (acetylacetonato)bis{4,6-dimethyl 2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN3]phenyl- {κC}iridium(III) (abbreviation: Ir(dmppm-dmp)2(acac)), ( Acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III)( Abbreviation: Ir(dppm)2(acac) (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazine) Iridium(III) (abbreviation: Ir(mppr-Me)2(acac)), (acetylacetonate ruacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinate)irid Pyrazine skeleton such as Ir(III) (abbreviation: Ir(mppr-iPr)2(acac)) Organometallic iridium complexes and tris(2-phenylpyridinato-N,C 2’ ) Iridium(III) (abbreviation: Ir(ppy)3), bis(2-phenylpyridinato-N ,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(ppy)2(ac ac)), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: Ir(bzq)2(acac)), tris(benzo[h]quinolinato)iridium Ir(III) (abbreviation: Ir(bzq)3), tris(2-phenylquinolinato-N,C 2 ’ ) Iridium(III) (abbreviation: Ir(pq)3), bis(2-phenylquinolinato- N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(pq)2(ac Organometallic iridium complexes with pyridine skeletons such as bis(2,4-difluorophenyl) and Venyl-1,3-oxazolato-N,C 2’ ) Iridium(III) acetylacetoner Ir(dpo)2(acac)), bis{2-[4'-(perfluorophenyl (phenyl)pyridinato-N,C 2’}Iridium(III) acetylacetonate ( Abbreviation: Ir(p-PF-ph)2(acac)), bis(2-phenylbenzothiazol -N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(bt)2(a In addition to organometallic iridium complexes such as tris(acetylacetonato)(monophenyl) Anthroline) terbium(III) (abbreviation: Tb(acac)3(Phen)) Among the above, the organometallic iridium complexes having a pyrimidine skeleton are Dium complexes are particularly preferred because they are remarkably excellent in reliability and luminous efficiency.

[0169] Examples of substances having a yellow or red emission peak include diisobutyryl Methanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(II I) (abbreviation: Ir(5mdppm)2(dibm)), bis[4,6-bis(3-methyl Phenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: Ir (5mdppm)2(dpm)), bis[4,6-di(naphthalene-1-yl)pyrimidinyl] Nato](dipivaloylmethanato)iridium(III) (abbreviation: Ir(d1npm)2( Organometallic iridium complexes with pyrimidine skeletons such as (acetylacetamide) Iridium(III) r(tppr)2(acac)), bis(2,3,5-triphenylpyrazine)(dipyridine) Valoylmethanato)iridium(III) (abbreviation: Ir(tppr)2(dpm)), ( Acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]i Ir(Fdpq)2(acac) and other pyrazine-based compounds Organometallic iridium complexes and tris(1-phenylisoquinolinato-N,C 2’ ) Iridium(III) (abbreviation: Ir(piq)3), bis(1-phenylisoquinolinato -N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(piq)2( In addition to organometallic iridium complexes with pyridine skeletons such as acac), 2,3,7, 8,12,13,17,18-Octaethyl-21H,23H-porphyrin platinum(II) ) (abbreviation: PtOEP) and tris(1,3-diphenyl-1,3-propanediol). (Eu(DB))(monophenanthroline)europium(III) M) 3(Phen)), tris[1-(2-thenoyl)-3,3,3-trifluoroacetate [Tonato](monophenanthroline)europium(III) (abbreviation: Eu(TTA)3( Among the above, rare earth metal complexes such as pyrimidine skeletons are Organometallic iridium complexes having the above structure are particularly preferred because they are extremely reliable and have excellent luminous efficiency. In addition, organometallic iridium complexes with pyrazine skeletons can emit red light with good chromaticity. can be done.

[0170] In addition to phosphorescent compounds, other materials that can convert triplet excitation energy into light include: Thermally activated delayed fluorescence Therefore, they are called phosphorescent compounds. The part may be read as a thermally activated delayed fluorescent compound. The difference between the singlet and triplet excited energy levels of the photoactive compound is small. It has the function of converting triplet excitation energy to singlet excitation energy by reverse intersystem crossing. Therefore, a small amount of thermal energy can convert the triplet excited state to a singlet excited state. It is possible to upconvert (reverse intersystem crossing) the singlet excited state, and efficiently emit light (fluorescence) from the singlet excited state. The conditions for efficient thermally activated delayed fluorescence are The difference between the excited energy level and the triplet excited energy level is preferably greater than 0 eV. 0.3 eV or less, more preferably greater than 0 eV and less than 0.2 eV, and even more preferably 0 eV or more and 0.1 eV or less.

[0171] When the thermally activated delayed fluorescent compound is composed of one kind of material, for example, the following material is used: It can be used.

[0172] First, fullerene and its derivatives, acridine derivatives such as proflavine, and eosin are listed. In addition, magnesium (Mg), zinc (Zn), cadmium (Cd), tin (S n), platinum (Pt), indium (In), or palladium (Pd) Examples of the metal-containing porphyrin include protoporphyrin. Porphyrin-tin fluoride complex (SnF2(Proto IX)), mesoporphyrin-fluoride Tin complex (SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (Sn F2 (Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride Complex (SnF2(Copro III-4Me)), Octaethylporphyrin-fluoride Tin complex (SnF2(OEP)), etioporphyrin-tin fluoride complex (SnF2(E tio I)), octaethylporphyrin-platinum chloride complex (PtCl2OEP), etc. Can be obtained.

[0173] In addition, as a thermally activated delayed fluorescent compound composed of one kind of material, a π-electron-rich complex Heterocyclic compounds having a heteroaromatic skeleton and a π-electron deficient heteroaromatic skeleton can also be used. Specifically, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindoline) PIC -TRZ), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H -Carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2-[4-(10H-phenoxazin-10-yl)phenyl nyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3- [4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4, 5-Diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9 -Dimethyl-9H-acridin-10-yl)-9H-xanthen-9-one (abbreviation: A CRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl 10-phenyl-10H,10'H-spiro[phenyl]sulfone (abbreviation: DMAC-DPS) [Acridine-9,9'-anthracene]-10'-one (abbreviation: ACRSA) The heterocyclic compound has a π-electron rich heteroaromatic skeleton and a π-electron deficient heteroaromatic skeleton. Since the π-electron deficient complex has a high electron transporting property and hole transporting property, it is preferable. Among the aromatic skeletons, the diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton) or triazine skeleton is preferred because it is stable and has good reliability. Among the heteroaromatic skeletons, the acridine skeleton, the phenoxazine skeleton, the phenothiazine skeleton, The furan skeleton, the thiophene skeleton, and the pyrrole skeleton are stable and reliable. It is preferable that the compound has one or more selected from the group consisting of pyrrole and pyrrole. The skeleton includes an indole skeleton, a carbazole skeleton, and a 9-phenyl-3,3'-biphenyl skeleton. 9H-carbazole skeleton is particularly preferred. The substance in which the heteroaromatic skeleton is directly bonded to the π-deficient heteroaromatic skeleton exhibits the donor property of the π-electron-rich heteroaromatic skeleton. The acceptor properties of the π-electron-deficient heteroaromatic skeleton are both strong, and the singlet excited energy level This is particularly preferred because the difference between the triplet excitation energy level and the triplet excitation energy level becomes small.

[0174] In addition, materials that exhibit thermally activated delayed fluorescence can be independently converted from a triplet excited state to a single excited state by reverse intersystem crossing. The material may be capable of generating a doublet excited state, or may be an exciplex (or The material may be made of multiple materials that form a single layer (also called an exciplex).

[0175] The host materials used in the light-emitting layer 140, the light-emitting layer 2140, and the light-emitting layer 2170 are , a hole transporting material and an electron transporting material can be used.

[0176] The host material of the light-emitting layer may be any of the following: For example, tris(8-quinolinolato)aluminum(III) (abbreviation: Alq3), Tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq3), Bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq 2) 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: ZnPB O), bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBT Z), 2-(4-biphenylyl)-5-(4-tert-butylphenyl )-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-ter t-Butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: O XD-7), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butyl) phenyl)-1,2,4-triazole (abbreviation: TAZ), 2,2',2''-(1,3, 5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: T PBI), Bathocuproine (abbreviation: BCP), 9-[4-(5-phenyl-1,3,4 -Oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11) Which heterocyclic compound, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl 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-phenyl Examples of aromatic amine compounds include aromatic amine compounds such as phenylamino]biphenyl (abbreviation: BSPB). Anthracene derivatives, phenanthrene derivatives, pyrene derivatives, chrysene derivatives, dibenzo [g,p]Chrysene derivatives and other condensed polycyclic aromatic compounds are included. -Diphenylanthracene (abbreviation: DPAnth), N,N-diphenyl-9-[4-( 10-Phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation : CzA1PA), 4-(10-phenyl-9-anthryl)triphenylamine (abbreviation :DPhPA), YGAPA, PCAPA, N,9-diphenyl-N-{4-[4-(1 0-Phenyl-9-anthryl)phenyl]phenyl}-9H-carbazole-3-amine PCAPBA, 2PCAPA, 6,12-dimethoxy-5,11-diphenyl Luchrysene, DBC1, 9-[4-(10-phenyl-9-anthracenyl)phenyl] -9H-Carbazole (abbreviation: CzPA), 3,6-diphenyl-9-[4-(10-phenyl (phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: DPCzPA), ,10-Bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 9,1 0-Di(2-naphthyl)anthracene (abbreviation: DNA), 2-tert-butyl-9,1 0-Di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 9,9'-bianthri BANT, 9,9'-(stilbene-3,3'-diyl)diphenanthrene (abbreviation: DPNS), 9,9'-(stilbene-4,4'-diyl)diphenanthrene ( DPNS2), 1,3,5-tri(1-pyrenyl)benzene (TPB3), etc. Among these and various other substances, the energy gap of the light-emitting material is One or more materials with an energy gap larger than the In addition, when the light-emitting material is a phosphorescent compound, the host material may be a All that is required is to select a substance whose triplet excitation energy is greater than the triplet excitation energy.

[0177] In addition, when multiple materials are used as the host material of the light-emitting layer, two types of materials that form an exciplex are In this case, it is preferable to use a combination of various carrier transport materials. However, in order to efficiently form an exciplex, it is necessary to use an electron transporting material and a positive Combining with a hole transporting material is particularly preferred.

[0178] This is because an exciplex is formed by combining an electron transport material and a hole transport material. When the host material is used, the mixing ratio of the electron transport material and the hole transport material is adjusted. This makes it easy to optimize the carrier balance between holes and electrons in the light-emitting layer. By optimizing the carrier balance of holes and electrons in the light-emitting layer, By suppressing the bias of the area where recombination occurs, As a result, the reliability of the light-emitting element can be improved.

[0179] Electron transport materials include metal complexes containing zinc or aluminum, and nitrogen-containing heteroaromatic compounds. A π-electron deficient heteroaromatic compound such as the compound Bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq 2) 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: ZnPB O), bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBT Z) and 2-(4-biphenylyl)-5-(4-tert-butylphenyl) 3-(4-biphenylyl)-4-oxadiazole (abbreviation: PBD), -Phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation :TAZ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxo Sadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl- 1,3,4-Oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: C O11), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl -1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophene- 4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBI Heterocyclic compounds with azole skeletons such as 2-[3-(dibenzothiophene)m-II] and 2mDBTPDBq -II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibe Benzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9 H-Carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (Abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H-carbazole -9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-II I) 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quino Xaline (abbreviation: 7mDBTPDBq-II) and 6-[3-(dibenzothiophene -4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq- II), 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation : 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pi Rimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carba 4,6mCzP2Pm, 4-{3- [3'-(9H-carbazol-9-yl)]biphenyl-3-yl}benzofuro[3, 2-d]pyrimidine (abbreviation: 4mCzBPBfpm) and other heterocycles with a diazine skeleton Compounds such as 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H- Carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine ( Abbreviation: PCCzPTzn), 2,4,6-tris[3'-(pyridin-3-yl)biphenyl] Nyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz), 2,4,6- Tris(2-pyridyl)-1,3,5-triazine (abbreviation: 2Py3Tzn) and other triazines Heterocyclic compounds with azine skeletons and 3,5-bis[3-(9H-carbazole-9-yl] 1,3,5-tri[3-(phenyl)phenyl]pyridine (abbreviation: 35DCzPPy), Heterocycles with pyridine skeletons such as [lysyl]phenylbenzene (abbreviation: TmPyPB) Among the above, heterocyclic compounds having a diazine skeleton and a triazine skeleton are Compounds having a pyridine skeleton and heterocyclic compounds having a pyridine skeleton are preferred because of their high reliability. Heterocyclic compounds with azine (pyrimidine and pyrazine) and triazine skeletons have electrons It has high transportability and also contributes to reducing the driving voltage.

[0180] As hole transport materials, π-electron-rich heteroaromatic compounds (e.g., carbazole derivatives and indium arsenide derivatives) are used. 2-[Dole derivatives] or aromatic amines can be suitably used. N-(9-phenylcarbazol-3-yl)-N-phenylamino]spiro-9,9' -Bifluorene (abbreviation: PCASF), 4,4',4''-tris[N-(1-naphthyl )-N-phenylamino]triphenylamine (abbreviation: 1'-TNATA), 2,7-biphenylamine 9,9'-[N-(4-diphenylaminophenyl)-N-phenylamino]spiro Bifluorene (abbreviation: DPA2SF), N,N'-bis(9-phenylcarbazole-3 -yl)-N,N'-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N -(9,9-Dimethyl-2-diphenylamino-9H-fluoren-7-yl)diphenyl Diphenylamine (abbreviation:DPNF), N,N',N''-triphenyl-N,N',N''-triphenyl Tris(9-phenylcarbazol-3-yl)benzene-1,3,5-triamine (abbreviation :PCA3B), 2-[N-(9-phenylcarbazol-3-yl)-N-phenyla amino]spiro-9,9'-bifluorene (abbreviation: PCASF), 2-[N-(4-diphenyl N-phenylaminophenyl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: DPASF), N,N'-bis[4-(carbazol-9-yl)phenyl]-N,N' -Diphenyl-9,9-dimethylfluorene-2,7-diamine (abbreviation: YGA2F), 4,4'-Bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NP B) N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl] phenyl]-4,4'-diamine (abbreviation: TPD), 4,4'-bis[N-(4-diphenyl N-phenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), 4,4' -Bis[N-(spiro-9,9'-bifluoren-2-yl)-N-phenylamino]bi Phenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluorene-9-yl) 4-phenyl-3'-(9-phenyl)triphenylamine (abbreviation: BPAFLP) Fluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), N-(9,9- Dimethyl-9H-fluoren-2-yl)-N-{9,9-dimethyl-2-[N'-phenyl N-(9,9-dimethyl-9H-fluoren-2-yl)amino]-9H-fluorenyl Oren-7-yl}phenylamine (abbreviation: DFLADFL), 3-[N-(9-phenyl [N-phenylamino]-9-phenylcarbazole (abbreviation :PCzPCA1), 3-[N-(4-diphenylaminophenyl)-N-phenylamine No]-9-phenylcarbazole (abbreviation: PCzDPA1), 3,6-bis[N-(4- Diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation PCzDPA2), N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl {N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviation :DNTPD), 3,6-bis[N-(4-diphenylaminophenyl)-N-(1-na 3,6-bis(phenyl)amino]-9-phenylcarbazole (abbreviation: PCzTPN2), [N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenyl Carbazole (abbreviation: PCzPCA2), 4-phenyl-4'-(9-phenyl-9H- Carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-di Phenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine PCBBi1BP, 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)triphenyl PCBNBB, 3-[N-(1-naphthyl)-N-(9-phenylcarbamoyl) carbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1) , 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole- 3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N -[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9' -Bifluorene-2-amine (abbreviation: PCBASF), N-(4-biphenyl)-N-( 9,9-Dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-carbazole -3-amine (abbreviation: PCBiF), N-(1,1'-biphenyl-4-yl)-N-[ 4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl- Aromatic amine skeleton such as 9H-fluorene-2-amine (abbreviation: PCBBiF) Compounds such as 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di (N-Carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenyl phenyl)-9-phenylcarbazole (abbreviation: CzTP), 9-phenyl-9H-3- (9-phenyl-9H-carbazol-3-yl)carbazole (abbreviation: PCCP), etc. Compounds with a carbazole skeleton such as 4,4',4''-(benzene-1,3,5-triphenylphosphine) 2,8-diphenyl)tri(dibenzothiophene) (abbreviation: DBT3P-II) -4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene Fluorene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluorene- 9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV) Compounds with thiophene skeletons such as 4,4',4''-(benzene-1,3,5- triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), 4-{3-[3-(9 -phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation :mmDBFFLBi-II) and other compounds having a furan skeleton. Among them, compounds with aromatic amine skeletons and compounds with carbazole skeletons have high reliability. In addition, the hole transporting property is high, and this contributes to reducing the driving voltage, which is preferable.

[0181] The combination of the host material that forms the exciplex is not limited to the above-mentioned compounds. It is a combination that can transport carriers without being disturbed and can form an exciplex. The emission of the exciplex occurs in the absorption band on the longest wavelength side of the absorption spectrum of the luminescent material (luminescent material (absorption corresponding to the transition from the singlet ground state to the singlet excited state of Other materials may also be used.

[0182] Furthermore, a thermally activated delayed fluorescent material may be used as the host material for the light-emitting layer.

[0183] In addition, the electron transport material used in the light emitting layer is the same as the electron transport material used in the electron injection layer. This allows the light-emitting element to be easily manufactured, and the light-emitting element can be easily manufactured. The manufacturing costs of the optical element can be reduced.

[0184] ≪Electron transport layer≫ The electron transport layer 118, the electron transport layer 2113, and the electron transport layer 2118 have a high electron transporting property. The electron transport layer 118, the electron transport layer 2113, and the electron transport layer 2118 are layers containing a substance. is a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand. Metal complexes having ligands, oxadiazole derivatives, triazole derivatives, phenanthro Examples of such derivatives include phosphorus derivatives, pyridine derivatives, and bipyridine derivatives. Compounds that can be used in the electron injection layer 130, the electron injection layer 2130, and the electron injection layer 2119 The metal complexes and heteroaromatic compounds exemplified above can be used. If the material has a high transporting property, the material other than the above can be used for the electron transport layer 118 and the electron transport layer 2113. and may be used as the electron-transporting layer 2118 .

[0185] In addition, the electron transport layer 118, the electron transport layer 2113, and the electron transport layer 2118 are each a single layer. In addition, two or more layers made of the above substances may be laminated.

[0186] In addition, between the electron transport layer 118 and the light emitting layer 140, between the electron transport layer 2113 and the light emitting layer 2140, A layer for controlling the movement of electron carriers is provided between the electron transport layer 2118 and the light emitting layer 2170. This is a material having a high electron transporting property and a material having a high electron trapping property. A layer in which a small amount of Zn is added, which suppresses the movement of electron carriers, thereby reducing carrier dispersion. This structure prevents electrons from penetrating the light-emitting layer. This is highly effective in suppressing problems caused by the above-mentioned problems (such as a decrease in element life).

[0187] In addition, the electron transporting material used in the electron transport layer is the same as the electron transporting material used in the electron injection layer. The electron transporting material used in the electron transport layer may be the same as that used in the light emitting layer. The same material as the electron transport material used in the present invention can be used. This allows the steps to be easily performed, thereby reducing the manufacturing cost of the light-emitting device.

[0188] The above-mentioned hole injection layer, hole transport layer, light emitting layer, electron transport layer, and electron injection layer are These methods include deposition (including vacuum deposition), inkjet, coating, and gravure printing. The hole injection layer, the hole transport layer, the light emitting layer, the electron In addition to the above-mentioned materials, the transport layer and the electron injection layer may be made of inorganic compounds such as quantum dots, or Polymeric compounds (oligomers, dendrimers, polymers, etc.) may also be used.

[0189] The quantum dots are classified into colloidal quantum dots, alloy quantum dots, and core-shell quantum dots. In addition, a group 2 and a group 16, a group 13 and a group 14, and a core type quantum dot may be used. Contains element groups 15, 13 and 17, 11 and 17, or 14 and 15 Quantum dots may also be used. Alternatively, cadmium (Cd), selenium (Se), zinc (Zn ), sulfur (S), phosphorus (P), indium (In), tellurium (Te), lead (Pb), gallium (Ga), Quantum dots containing elements such as Ga, Arsenic, and Aluminum are used. It's fine.

[0190] Examples of liquid media used in wet processes include methyl ethyl ketone, cyclohexane, etc. Ketones such as xanone, fatty acid esters such as ethyl acetate, halogens such as dichlorobenzene Hydrocarbons, aromatics such as toluene, xylene, mesitylene, and cyclohexylbenzene Hydrocarbons, aliphatic hydrocarbons such as cyclohexane, decalin, and dodecane, dimethylformamide, etc. Organic solvents such as dichloromethane (DMF) and dimethyl sulfoxide (DMSO) can be used. Cut.

[0191] Examples of polymer compounds that can be used in the light-emitting layer include poly[2-methoxy]phenylene. [MeH] -PPV), polyphenylenes such as poly(2,5-dioctyl-1,4-phenylenevinylene), Poly(9,9-di-n-octylfluorenyl-2,7 -diyl) (abbreviation: PF8), poly[(9,9-di-n-octylfluorenyl-2,7 -diyl)-alt-(benzo[2,1,3]thiadiazole-4,8-diyl)](abbreviation Name: F8BT), poly[(9,9-di-n-octylfluorenyl-2,7-diyl)- alt-(2,2'-bithiophene-5,5'-diyl)] (abbreviated as F8T2), poly[( 9,9-Dioctyl-2,7-Divinylenefluorenylene)-alt-(9,10-An thracene)], poly[(9,9-dihexylfluorene-2,7-diyl)-alt-( Polyfluorene derivatives such as poly(3-hexyl) Polyalkylthiophenes (P) such as silthiophene-2,5-diyl (abbreviation: P3HT) AT) derivatives, polyphenylene derivatives, etc. Poly(9-vinylcarbazole) (abbreviation: PVK), Poly(2-vinylnaphthalene), Ri[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (abbreviation: PTA A) or other polymer compound may be doped with a light-emitting low-molecular compound and used in the light-emitting layer. As the light-emitting low molecular weight compound, the fluorescent compounds listed above can be used.

[0192] Electrode 101, electrode 102, electrode 2101, electrode 2102, electrode 2103 and electrode 210 The electrode 101, the electrode 102, and the electrode 4 function as an anode or a cathode of the light-emitting element. 2101, electrode 2102, electrode 2103 and electrode 2104 are made of a metal, an alloy, a conductive compound, etc. and mixtures or laminates thereof.

[0193] Electrode 101 or electrode 102, electrode 2101, electrode 2103 and electrode 2104 or One of the poles 2102 is made of a conductive material having a function of reflecting light. The conductive material is preferably aluminum (Al) or an alloy containing Al. The alloys containing Al are Al and L (L is titanium (Ti), neodymium (Nd)). , nickel (Ni), and lanthanum (La) Examples include alloys containing Al and Ti, or Al, Ni and La. Aluminum has low resistance and high light reflectivity. Aluminum is abundant in the earth's crust. Since aluminum is abundant and inexpensive, the manufacturing cost of light-emitting elements can be reduced by using aluminum. In addition, silver (Ag) is suitable for use as an electrode material because of its high light reflectance. Ag is a group 11 transition metal, and can be used in the electron injection method according to one embodiment of the present invention. When Ag is used as the cathode of a light-emitting device using Ag as the injection layer, the adhesion between the electrode and the electron injection layer is improved. It is preferable because it improves the solubility of the material. Or Ag and N (N is yttrium (Y), Nd, magnesium Mg, Yb, Al, Ti, Gallium (Ga), Zinc (Zn) , indium (In), tungsten (W), manganese (Mn), tin (Sn), iron (F e), Ni, copper (Cu), palladium (Pd), iridium (Ir), or gold (Au) As an alloy containing silver, for example, For example, an alloy containing silver, palladium and copper, an alloy containing silver and copper, an alloy containing silver and magnesium, Examples include alloys containing silver and nickel, alloys containing silver and gold, and alloys containing silver and ytterbium. Other metals include tungsten, chromium (Cr), molybdenum (Mo), copper, and titanium. A transition metal can be used.

[0194] The light emitted from the light-emitting layer is emitted from one or both of the electrodes 101 and 102, 2101, through one or both of electrodes 2103 and 2104 or electrode 2102 Therefore, at least one of the electrodes 101 and 102, the electrode 210 1. At least one of the electrodes 2103 and 2104 or the electrode 2102 is a light-transmitting It is preferable that the conductive material is a material having a function of transmitting visible light. The transmittance of the film is 40% or more and 100% or less, preferably 60% or more and 100% or less, and has a resistivity of 1×10 -2 Examples include conductive materials with a resistance of Ω·cm or less.

[0195] In addition, the electrodes 101, 102, 2101, 2102, 2103, and 2104 is made of a conductive material that has the function of transmitting light and the function of reflecting light. The conductive material may preferably have a visible light reflectance of 20% or more and 80% or less. The resistivity is 1×10 -2 Conductivity below Ω·cm For example, conductive metals, alloys, conductive compounds, etc. can be used alone or in combination. It can be formed by using several kinds of materials. Specifically, for example, indium tin oxide (Ind Indium tin oxide (ITO), a compound containing silicon or silicon oxide ITSO, Indium Zinc Oxide e) Indium-tin oxide containing titanium, indium-titanium oxide, titanium oxide Metal oxides such as indium oxide with tin and zinc oxide can be used. In addition, a thin metal film that transmits light (preferably, a thickness of 1 nm to 30 nm) is used. Examples of metals that can be used include Ag, Ag and Al, Ag and Mg, Alloys of Ag and Au, Ag and Yb, etc. can be used.

[0196] The conductive layer 2101b, the conductive layer 2103b, and the conductive layer 2104b have the above-mentioned light transmitting function. It is preferable that the conductive layer 2101a and the conductive layer 2102 are made of a conductive material having a function. The conductive layer 2104a is made of the conductive material having the above-mentioned light reflecting function and the light transmitting function. A conductive material having a function of transmitting and reflecting light, It is preferably formed from a material.

[0197] In this specification and the like, a material having a function of transmitting light is a material having a function of transmitting visible light. Any material having the above and having electrical conductivity may be used, and examples thereof include ITO. In addition to oxide conductors, oxide semiconductors and organic conductors containing organic substances are also included. The organic conductor containing the electron donor is, for example, a mixture of an organic compound and an electron donor. Examples of such materials include composite materials made by mixing organic compounds and electron acceptors. Alternatively, an inorganic carbon-based material such as graphene may be used. The rate is preferably 1×10 5 Ω cm or less, more preferably 1×10 4 Ω cm The following is the result.

[0198] In addition, by laminating a plurality of the above materials, one or both of the electrodes 101 and 102 can be formed. Both electrodes 2101, 2103, and either electrode 2104 or electrode 2102 are Either or both may be formed.

[0199] In order to improve the light extraction efficiency, the electrode is in contact with the light transmitting electrode. A material having a higher refractive index than the electrode may be used. As long as the material has the function of providing the above, it may be a material that is conductive or not. For example, in addition to the oxide conductors described above, oxide semiconductors and organic materials can be used. The organic material may be, for example, a light-emitting layer, a hole-injecting layer, a hole-transporting layer, an electron-transporting layer, or an electron The materials listed for the electron injection layer are also available. Inorganic carbon-based materials and metals that are light-transmitting are also available. A thin film may also be used, and multiple layers of several nanometers to several tens of nanometers may be laminated.

[0200] When the electrode 101 or the electrode 102 functions as a cathode, the work function is small. (3.8 eV or less) material. When either electrode 2104 or electrode 2102 functions as a cathode, It is preferable to have materials with a small function (3.8 eV or less).

[0201] In addition, when the electrode 101 or the electrode 102 is used as an anode, the electrode having a large work function (4. 0 eV or more) material is preferably used. When either the electrode 2104 or the electrode 2102 is used as an anode, It is preferable to use a material having a refractive index of 4.0 eV or more.

[0202] The electrodes 101 and 102 are made of a conductive material having a function of reflecting light and a conductive material having a function of transmitting light. In this case, the electrode 101 and the electrode 102 may be laminated with a conductive material having a permeability function. 02 can resonate light of a desired wavelength from each light-emitting layer and intensify the light of the desired wavelength. In this way, the electrode 2 can have a function of adjusting the optical distance. 101, either the electrode 2103 and the electrode 2104 or the electrode 2102 reflects light. It can also be used as a laminate of a conductive material having a function of transmitting light and a conductive material having a function of transmitting light. In this case, the electrodes 2101, 2102, 2103, and 2104 are The light of the desired wavelength from the optical layer is resonated so that the light of the desired wavelength can be intensified. This is preferable because it has the function of adjusting the distance.

[0203] Electrode 101, electrode 102, electrode 2101, electrode 2102, electrode 2103 and electrode 210 The deposition methods of 4 are sputtering, deposition, printing, coating, MBE (Molecular Beam Epitaxy) and Ar Beam Epitaxy, CVD, Pulsed Laser Deposition, ALD (Ato A method such as a multi-layer deposition (MLD) method can be used as appropriate.

[0204] <Microcavity structure> In the light-emitting element according to one embodiment of the present invention, for example, the electrode 2101 shown in FIG. The electrode 2101 is formed of a conductive material having a function of transmitting light and reflecting light. The micro-optical resonator (microcavity) is made of a conductive material that has the function of reflecting light. By adopting this structure, light emitted from the light-emitting layer 2140 or the light-emitting layer 2170 is reflected by the gap between the two electrodes. This causes resonance and increases the intensity of light of a desired wavelength emitted from the electrode 2102. can be done.

[0205] Here, the case where light is extracted from the electrode 2102 side (cathode side) will be described. It is also possible to adopt a configuration in which light is extracted from the electrode 2101 side (anode side). The electrode 2101 is made of a conductive material having a function of reflecting and transmitting light. The light emitting element 11 may be formed of a conductive material having a reflecting function.

[0206] The light emitted from the light emitting layer 2140 and the light emitting layer 2170 is guided by a pair of electrodes (for example, electrodes 2101 and electrode 2102). The electrode is formed at a position where the intensity of light of a desired wavelength is increased. The optical distance from the reflective area of ​​2101 to the luminous area of ​​the luminous layer 2170 and the reflective area of ​​the electrode 2102 are By adjusting the optical distance from the illuminating region to the light emitting region of the light emitting layer 2170, It is possible to increase the intensity of light of a desired wavelength among the light emitted from 2170. The optical distance from the reflecting area of ​​the electrode 2101 to the light emitting area of ​​the light emitting layer 2140 and the By adjusting the optical distance from the reflection area to the light emitting area of ​​the light emitting layer 2140, the light emission It is possible to increase the intensity of light of a desired wavelength among the light emitted from the layer 2140. That is, a light emitting element in which a plurality of light emitting layers (here, light emitting layer 2140 and light emitting layer 2170) are laminated. In this case, it is preferable to optimize the optical distances of the light emitting layer 2140 and the light emitting layer 2170. I wish.

[0207] For example, in order to amplify light of a desired wavelength (wavelength: λ) obtained from the light emitting layer 2140, The region where light of a desired wavelength of the light emitting layer 2140 can be obtained from the reflection region of the electrode 2101 (light emitting region ) and the light of the desired wavelength of the light emitting layer 2140 is obtained from the reflective area of ​​the electrode 2102. and the optical distance to the area (light emitting area) where the light is emitted, are (2m'-1)λ / 4 (where, It is preferable to adjust the light-emitting region so that it is close to m′ (m is a natural number). 2 shows the recombination region of holes and electrons in light-emitting layer 2140.

[0208] By performing such optical adjustment, the emission spectrum obtained from the light emitting layer 2140 can be narrowed. It is possible to obtain light having good color purity.

[0209] <Substrate> In addition, the light-emitting element according to one embodiment of the present invention is provided on a substrate made of glass, plastic, or the like. Regarding the order of fabrication on the substrate, the layers may be stacked in order from the electrode 101 side. The light emitting element 2250a and the light emitting element 2250b may be laminated in order from the electrode 102 side. In this case, the electrodes 2101, 2102, and 2103 may be stacked in this order. The layers may be laminated in order from the two sides.

[0210] The substrate on which the light-emitting element according to one embodiment of the present invention can be formed is, for example, glass or quartz. A flexible substrate may be used. The substrate is a flexible substrate, such as polycarbonate. Examples of the substrate include plastic substrates made of polyacrylate and polyarylate. In addition, a film made by vapor deposition may be used in the manufacturing process of the light-emitting element and the optical element. Any other material may be used as long as it functions as a support in the light-emitting device. Anything that has the function of protecting the element and the optical element may be used.

[0211] For example, in the present invention, a light emitting element can be formed using various substrates. The type of the substrate is not particularly limited. An example of the substrate is a semiconductor substrate (e.g., a single crystal substrate or silicon substrate), SOI substrate, glass substrate, quartz substrate, plastic substrate, metal Substrate, stainless steel substrate, substrate with stainless steel foil, tungsten substrate, substrate with tungsten foil, flexible substrate, laminated film, fibrous These include cellulose nanofibers (CNF), paper, and base films that contain the above materials. Examples of glass substrates include barium borosilicate glass, aluminoborosilicate glass, or Soda lime glass, etc. Flexible substrates, laminated films, base films, etc. Examples include polyethylene terephthalate (PET), poly Polyethylene naphthalate (PEN), polyethersulfone (PES), polytetrafluoroethylene Examples of plastics include PTFE (polytetrafluoroethylene). Resins such as acrylic resins are also available. Examples include polypropylene, polyester, and polypropylene. Examples include polyvinyl fluoride, polyvinyl chloride, etc., or polyamide, Examples include polyimide, aramid, epoxy, inorganic vapor deposition film, and paper.

[0212] In addition, a flexible substrate may be used as the substrate, and the light emitting element may be formed directly on the flexible substrate. Alternatively, a release layer may be provided between the substrate and the light-emitting element. After a part or all of a chip is completed, it is separated from the board and used to transfer it to another board. In this case, the light-emitting element can be transferred onto a substrate having poor heat resistance or a flexible substrate. The above-mentioned peeling layer has a laminated structure of inorganic films, for example, a tungsten film and a silicon oxide film. or a structure in which a resin film such as polyimide is formed on a substrate.

[0213] That is, a light emitting element is formed using a certain substrate, and then the light emitting element is transferred to another substrate. The light emitting element may be disposed on another substrate. In addition to the above mentioned substrates, cellophane substrates, stone substrates, wood substrates, fabric substrates (natural fibers (silk, cotton, Hemp), synthetic fibers (nylon, polyurethane, polyester) or regenerated fibers (acetate (including cellulose, cupra, rayon, recycled polyester, etc.), leather substrate, rubber substrate, etc. By using these substrates, light-emitting elements that are not easily broken and have high heat resistance can be produced. The light emitting element may be a small light emitting element, a light emitting element that is lighter in weight, or a light emitting element that is thinner.

[0214] Also, for example, a field effect transistor (FET) is formed on the above-mentioned substrate, and the FET and The light emitting element 150, the light emitting element 2250a, and the light emitting element 2250 are electrically connected to the electrodes. In this way, an active layer for controlling the driving of a light-emitting element by a FET may be fabricated. A matrix type display device can be manufactured.

[0215] In addition, the substrate 2220 on which the optical element is formed can be any of the substrates listed above. Cut.

[0216] ≪Light blocking layer≫ The light-shielding layer 2223 has a function of suppressing reflection of external light. The light-shielding layer 22 has a function of preventing the color mixture of light emitted from adjacent light-emitting elements. 23 includes metals, resins containing black pigments, carbon black, metal oxides, and multiple gold For example, a composite oxide containing a solid solution of metal oxides can be used.

[0217] <Optical elements> The optical elements 2224B, 2224G, and 2224R receive the incident light. For example, the optical element 2224B has a function of selectively transmitting light of a specific color. The light emitted from the region 2222B through the optical element 2 is blue light. The light emitted from the region 2222G via the region 224G is green light. The light emitted from the region 2222R via the optical element 2224R is red. Become light.

[0218] The optical elements 2224R, 2224G, and 2224B may include, for example, Color layers (also called color filters), bandpass filters, multilayer filters, etc. can be applied. In addition, a color conversion element can be applied to the optical element. It is an optical element that converts the wavelength of the light into light with a longer wavelength than the wavelength of the light. The use of quantum dots makes it possible to improve the color of the display device. Reproducibility can be improved.

[0219] In addition, other light may be projected onto the optical elements 2224R, 2224G, and 2224B. One or more optical elements may be stacked. Examples of other optical elements include a circular polarizing plate and The circular polarizing plate is used to prevent light from being emitted from the light emitting element of the display device. When the light is reflected from the outside of the display device, the light is reflected inside the display device. In addition, by providing an anti-reflection film, the display device This can weaken the external light reflected by the surface of the display device. It can be clearly observed.

[0220] ≪Bulkhead≫ The partition wall 2145 may be formed using an inorganic or organic material as long as it has insulating properties. The inorganic material may be silicon oxide, silicon oxynitride, silicon nitride oxide, or nitride. Examples of the organic material include silicon, aluminum oxide, and aluminum nitride. For example, photosensitive resin materials such as acrylic resin and polyimide resin can be used.

[0221] The silicon oxynitride film is a film whose composition contains more oxygen than nitrogen. Preferably, oxygen is 55 atomic % or more and 65 atomic % or less, and nitrogen is 1 atomic % or more and 20 atomic % or less. Silicon is 25 atomic % or more and 35 atomic % or less, and hydrogen is 0.1 atomic % or more and 10 atomic % or less. The silicon nitride oxide film is a film that contains more nitrogen than oxygen as its composition. It refers to a film with a high content of nitrogen, preferably 55 atomic % to 65 atomic % and 1 % to 20 atomic %, silicon is 25 atomic % to 35 atomic %, hydrogen is 0.1 atomic % This refers to a film containing this element in a concentration range of 10 atomic % or more.

[0222] The structure shown in this embodiment mode can be used in appropriate combination with other embodiment modes. Cut.

[0223] (Embodiment 2) In this embodiment mode, a light-emitting element having a different structure from that of the light-emitting element shown in Embodiment 1 is used. The light emitting mechanism of the light emitting device will be described below with reference to FIG. In this case, the parts having the same functions as those shown in FIG. 1(A) are indicated with the same hatch pattern. In addition, parts having similar functions are given similar reference symbols. , detailed description of which may be omitted.

[0224] <Configuration Example 5 of Light-Emitting Element> FIG. 3 is a schematic cross-sectional view of the light emitting element 250 and the light emitting element 252. As shown in FIG.

[0225] The light emitting element 250 and the light emitting element 252 shown in FIGS. 3A and 3B each include a pair of electrodes (electrodes 3A and 3B, a plurality of light-emitting units (101 and electrode 102) are disposed between the light-emitting units ( The light emitting element 250 and the light emitting unit 106 and the light emitting unit 108 are also included. In the optical element 252, the electrode 101 functions as an anode and the electrode 102 functions as a cathode. However, the following description will be given assuming that the light emitting element 250 has the opposite configuration.

[0226] In addition, in the light-emitting element 250 and the light-emitting element 252 shown in FIGS. The unit 106 and the light-emitting unit 108 are laminated. A charge generating layer 115 is provided between the light emitting unit 106 and the light emitting unit 108. The optical units 108 may be of the same or different construction.

[0227] The light emitting element 250 and the light emitting element 252 each have a light emitting layer 140 and a light emitting layer 170. In addition to the light-emitting layer 170, the light-emitting unit 106 also includes a hole injection layer 111, a hole transport The light-emitting unit 10 also includes a layer 112, an electron transport layer 113, and an electron injection layer 114. In addition to the light-emitting layer 140, the pixel element 8 includes a hole injection layer 116, a hole transport layer 119, an electron transport layer 118, and an electron injection layer 130.

[0228] The electron injection layer 114 and the electron injection layer 130 are formed of the same material as described in the first embodiment. A composite material of an organic compound having an electron pair can be preferably used. In this way, a light-emitting element having excellent moisture resistance, good reliability, and a low driving voltage can be provided. As shown in FIG. 3B, a light-emitting element 252 is formed by combining an electron injection layer 130 and an electrode 1. A charge generating layer 160 may be provided between the first and second electrodes 02. This structure provides further moisture resistance and acid resistance. It is possible to provide a device having excellent chemical properties.

[0229] As described above, the charge generating layer 115 and the charge generating layer 160 are formed of a hole transport material and an electron acceptor. Even if an acceptor substance is added to the electron transport material, the electron donor A donor substance may be added to the structure. Also, both of these structures may be laminated. By adopting this structure, a light-emitting element having excellent moisture resistance can be easily manufactured. do.

[0230] In the light-emitting element according to one embodiment of the present invention, the charge generation layer 115 and the charge generation layer 160 are For example, the charge generating layer 115 and the charge generating layer 160 may be made of the same material. The acceptor material may be the same as the hole transport material. This is preferable because a light-emitting device having excellent light-emitting properties can be easily fabricated.

[0231] The charge generating layer 115 sandwiched between the light emitting unit 106 and the light emitting unit 108 is When a voltage is applied between the electrode 101 and the electrode 102, electrons are injected into one of the light-emitting units, It is sufficient if the hole is injected into the other light-emitting unit. For example, as shown in FIG. 3(A) and (B), A voltage is applied so that the potential of electrode 101 is higher than the potential of electrode 102. When the charge generating layer 115 is turned on, the charge generating layer 115 injects electrons into the light-emitting unit 106 and the charge generating layer 115 injects electrons into the light-emitting unit 108. Holes are injected into the

[0232] In addition, in FIG. 3(A) and (B), a light-emitting element having two light-emitting units is shown. However, the same applies to a light emitting device in which three or more light emitting units are stacked. As shown in the light-emitting element 250, a plurality of light-emitting units are disposed between a pair of electrodes. By separating the charge generating layers, it is possible to achieve high brightness emission while keeping the current density low. Furthermore, it is possible to realize a light emitting element having a longer life. This can be done.

[0233] 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. The guest unit 106 and the light-emitting unit 108 have the same color light emission properties. When the material is included, the light emitting element 250 and the light emitting element 252 can emit light with high luminance at a small current value. In addition, the light-emitting unit 106 and the light-emitting unit 108 are When the light-emitting element 250 has guest materials each having a function of emitting light of a different color, In this case, the light-emitting layer 140 and the light-emitting layer 170 are preferably light-emitting elements that emit light in multiple colors. By using multiple light-emitting materials with different emission wavelengths for either or both of the The emission spectrum of the light emitting element 250 is a composite of emissions having different emission peaks. Therefore, the emission spectrum has at least two maxima.

[0234] The above-mentioned structure is also suitable for obtaining white light emission. By making the lights complementary to each other, white light can be obtained. The design is such that the resulting white light has a high light emission, or at least light emission having red, green and blue colors. It is preferable to select a material that is

[0235] In addition, in the case of a light-emitting element having three or more stacked light-emitting units, the The emission colors of the guest materials may be the same or different. In the case where a plurality of light-emitting units that emit light are included, the emission colors of the plurality of light-emitting units are as follows: Compared to other colors, it is possible to obtain high luminance with a small current value. The composition can be suitably used for adjusting the luminous color. This is suitable when using a guest material that exhibits a luminescent color. For example, In this case, two layers of light-emitting units having fluorescent compounds of the same color are arranged, and a layer of a light-emitting unit having a different fluorescent compound is arranged. By forming a light-emitting unit having a phosphorescent compound that emits a luminescent color into a single layer, it is possible to achieve both fluorescent and phosphorescent emission. The light emission intensity can be adjusted by changing the number of light emitting units. The strength can be adjusted.

[0236] In the case of a light-emitting device having two layers of such fluorescent light-emitting units and one layer of a phosphorescent light-emitting unit, Two layers of light-emitting units containing color fluorescent compounds and one layer of light-emitting units containing yellow phosphorescent compounds A light-emitting element containing a blue fluorescent compound or a light-emitting unit containing a red phosphorescent compound. and a light-emitting device having one light-emitting layer unit containing a green phosphorescent compound, and a blue fluorescent compound The light-emitting unit is composed of two layers of a red phosphorescent compound, a yellow phosphorescent compound, and a green phosphorescent compound. In the case of a light-emitting element having one light-emitting layer unit containing I wish.

[0237] In addition, at least one of the light-emitting layer 140 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 a hole transporting property is used as the host material of the first light-emitting layer, and a material having a hole transporting property is used as the host material of the second light-emitting layer. In this case, a material having an electron transporting property is used as the host material. The light-emitting material in the light-emitting layer and the second light-emitting layer may be the same or different. Even if a material has a function of emitting light of the same color, it is preferable that the material has a function of emitting light of different colors. The material may be a material having the following function: By using a material with a structure that has three primary colors or four or more colors, it is possible to obtain white light with high color rendering. It is also possible.

[0238] The light-emitting unit 106, the light-emitting unit 108, and the charge generating layer 115 are formed by deposition ( (including vacuum deposition), inkjet printing, coating, gravure printing, etc. can be done.

[0239] Note that the structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. There can be.

[0240] (Embodiment 3) In this embodiment, a light-emitting device using the light-emitting element shown in Embodiments 1 and 2 is An example will be described below with reference to FIGS.

[0241] FIG. 4(A) is a top view showing a light-emitting device, and FIG. 4(B) is a cross-sectional view of FIG. 4(A) along lines AB and CD. This light emitting device is a cross-sectional view of a light emitting element. The illustrated driving circuit section (source side driving circuit) 601, pixel section 602, and driving circuit section (gate side The driver circuit 603 is a sealing substrate 604, a desiccant 625, and a shielding circuit 605. The inside surrounded by the sealing material 605 is a space 607 .

[0242] The lead wiring 608 is connected to the source side driver circuit 601 and the gate side driver circuit 603. The wiring is for transmitting the signals to be input, and the FPC (flexible printed circuit board) is the external input terminal. Video signal, clock signal, start signal, reset signal, etc. from the 609 Although only the FPC is shown here, the FPC has a printed wiring board. Even if a printed wiring board (PWB) is installed, The light emitting device in this specification includes not only the light emitting device itself but also an FPC or This includes the state where the PWB is installed.

[0243] Next, a cross-sectional structure of the light emitting device will be described with reference to FIG. A driving circuit section and a pixel section are formed on the source side driving circuit section. A circuit 601 and one pixel in a pixel portion 602 are shown.

[0244] The source side driver circuit 601 includes an n-channel TFT 623 and a p-channel TFT 624. The driver circuit is a combination of various CMOS circuits, It may be formed of a MOS circuit or an NMOS circuit. This shows a driver integrated type with a driver circuit formed on the board, but this is not necessarily required. Alternatively, it may be formed externally.

[0245] The pixel section 602 includes a switching TFT 611, a current control TFT 612 and its drain. The pixel includes a first electrode 613 electrically connected to the input. An insulator 614 is formed so as to cover the end of the electrode 613. The insulating layer can be formed by using a photosensitive resin film having a mold.

[0246] In order to improve the coverage of the film formed on the insulator 614, the insulator 614 is The upper end or the lower end is formed to have a curved surface. For example, When photosensitive acrylic is used as the material, it is possible to make only the upper end of the insulator 614 curved. The radius of curvature of the curved surface is preferably 0.2 μm or more and 0.3 μm or less. The border 614 may be either a negative or positive photosensitive material.

[0247] An EL layer 616 and a second electrode 617 are formed on the first electrode 613. Here, the material used for the first electrode 613 functioning as an anode is a material having a work function of It is desirable to use a material with a large capacitance. For example, an ITO film or an indium tin oxide film containing silicon. Indium tin oxide film, indium oxide film containing 2wt% to 20wt% zinc oxide, nitride In addition to single-layer films such as titanium film, chromium film, tungsten film, Zn film, and Pt film, titanium nitride film and Lamination with a film mainly composed of aluminum, titanium nitride film and a film mainly composed of aluminum A three-layer structure of a titanium nitride film and a silicon nitride film can be used. The resistance of the anode is low, good ohmic contact can be achieved, and the anode can function as well. This can be done.

[0248] The EL layer 616 is formed by deposition using a deposition mask, inkjet printing, or spin coating. The EL layer 616 can be formed by various methods such as the above. The polymer may be a polymer compound (including an oligomer or a dendrimer).

[0249] Furthermore, a material for a second electrode 617 formed on the EL layer 616 and functioning as a cathode It is preferable to use a material having a small work function (such as Al) for the EL layer 61. In the case where the light generated in 6 is transmitted through the second electrode 617, the second electrode 617 is A thin metal film and a transparent conductive film (ITO, 2wt% to 20wt% zinc oxide) Indium oxide containing silicon, indium tin oxide containing silicon, zinc oxide (ZnO, etc.) It is preferable to use a laminate of the above.

[0250] The first electrode 613, the EL layer 616, and the second electrode 617 form a light-emitting element 618. The light emitting element 618 is a light emitting element having the configurations of the first and second embodiments. It is preferable that the pixel portion is formed with a plurality of light emitting elements. In the light emitting device of the embodiment, a light emitting device having the configuration described in the first and second embodiments is The light-emitting element may include both a light-emitting element and a light-emitting element having other configurations.

[0251] Furthermore, the sealing substrate 604 is bonded to the element substrate 610 with a sealant 605, A light emitting element is disposed in a space 607 surrounded by a child substrate 610, a sealing substrate 604, and a sealant 605. 618. The space 607 is filled with a filler. In addition to cases where inert gas (nitrogen, argon, etc.) is filled, resin, desiccant, or its Sometimes it is filled with both.

[0252] It is preferable to use epoxy resin or glass frit for the sealing material 605. It is desirable that these materials are as impermeable to moisture and oxygen as possible. Materials used for the sealing substrate 604 include glass substrates, quartz substrates, and FRP (Fiber Reinforced Plastics). reinforced plastics), PVF (polyvinyl fluoride), polyester A plastic substrate made of, for example, polyester or acrylic can be used.

[0253] As described above, a light emitting device using the light emitting elements described in the first and second embodiments can be obtained.

[0254] <Light-emitting device configuration example 1> FIG. 5 shows an example of a light-emitting device in which a light-emitting element that emits white light is formed and a color layer (color filter) is formed. An example of a light emitting device in which a GaN-GaN filter is formed is shown.

[0255] FIG. 5A shows a substrate 1001, an insulating base film 1002, a gate insulating film 1003, and a gate electrode. 1006, 1007, 1008, a first interlayer insulating film 1020, a second interlayer insulating film 1021 , a peripheral portion 1042, a pixel portion 1040, a driving circuit portion 1041, and a first electrode 102 of a light-emitting element. 4W, 1024R, 1024G, 1024B, partition wall 1026, EL layer 1028, light-emitting element 10, a second electrode 1029, a sealing substrate 1031, a sealant 1032, and the like are shown.

[0256] In addition, in FIG. 5(A) and FIG. 5(B), colored layers (red colored layer 1034R, green colored layer 10 34G, and a blue colored layer 1034B) are provided on a transparent substrate 1033. A black matrix 1035 may be further provided. The transparent base material 1033 is aligned and fixed to the substrate 1001. The color layers are covered with an overcoat layer 1036. In FIG. The light-emitting layer emits light to the outside without passing through the colored layers, and the light-emitting layer emits light to the outside by passing through the colored layers of each color. The light that does not pass through the colored layer is white, and the light that passes through the colored layer is red, blue, or green. This allows images to be displayed using four color pixels.

[0257] In FIG. 5B, a red colored layer 1034R, a green colored layer 1034G, and a blue colored layer 103 An example in which 4B is formed between the gate insulating film 1003 and the first interlayer insulating film 1020 is shown. As shown in FIG. 5B, the colored layer may be provided between the substrate 1001 and the sealing substrate 1031. stomach.

[0258] In the light emitting device described above, the light is taken in toward the substrate 1001 on which the TFT is formed. The light emitting device has a bottom emission structure, but the light is taken in from the sealing substrate 1031 side. The light emitting device may have a top emission structure.

[0259] <Configuration Example 2 of Light Emitting Device> A cross-sectional view of a top-emission type light-emitting device is shown in FIG. A connection electrode that connects the TFT and the anode of the light-emitting element can be formed. The process is the same as that of the bottom emission type light emitting device until the third interlayer is formed. An insulating film 1037 is formed to cover the electrode 1022. This insulating film serves to flatten the surface. The third interlayer insulating film 1037 may be made of the same material as the second interlayer insulating film 1021. It may also be formed using a variety of other materials.

[0260] Here, the first lower electrodes 1025W, 1025R, 1025G, and 1025B of the light-emitting element are The anode is assumed to be the anode, but it can also be the cathode. In the case of an optical device, the lower electrodes 1025W, 1025R, 1025G, and 1025B are reflective electrodes. The second electrode 1029 has a function of reflecting light and a function of transmitting light. In addition, the second electrode 1029 and the lower electrodes 1025W and 1025 A microcavity structure is applied between R, 1025G, and 1025B to amplify light of a specific wavelength. The EL layer 1028 has a structure as described in the second embodiment. The device has a structure capable of emitting white light.

[0261] In FIG. 5(A), FIG. 5(B), and FIG. 6, 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.

[0262] In the top emission structure shown in Figure 6, the colored layers (red colored layer 1034R, green colored layer The sealing can be performed by using a sealing substrate 1031 provided with a blue colored layer 1034G and a blue colored layer 1034B. The sealing substrate 1031 has a black layer (black matrix) between the pixels. A coloring layer (a red coloring layer 1034R, a green coloring layer 1035R, etc.) 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. .

[0263] In addition, although an example of full-color display using four colors, red, green, blue, and white, is shown here, the present invention is not limited to this. Alternatively, full color display may be performed using three colors, red, green, and blue. Alternatively, full color display may be performed using four colors, red, green, blue, and yellow. A full color display may be performed.

[0264] As described above, a light emitting device using the light emitting elements described in the first and second embodiments can be obtained.

[0265] Note that this embodiment mode can be appropriately combined with other embodiment modes.

[0266] (Embodiment 4) In this embodiment, a transistor that can be used in a display device according to one embodiment of the present invention will be described. The data will be described with reference to FIG.

[0267] The transistor shown in FIG. 7(A) is a so-called bottom gate channel etch structure transistor. The transistor is a transistor having a conductive layer 43 functioning as a gate electrode over a substrate 411. 1, an insulating layer 434 functioning as a gate insulating layer, a semiconductor layer 432, a source electrode, and The semiconductor device further includes a pair of conductive layers 433a and 433b which function as a drain electrode. A portion of the conductive layer 432 overlapping with the conductive layer 431 functions as a channel formation region. The conductive layer 432 is connected to the conductive layer 433a and the conductive layer 433b.

[0268] In addition, the transistor shown in FIG. The pair of impurity semiconductor layers 435 is a semiconductor layer 432 and a conductive layer. The conductive layer 433a is provided between the semiconductor layer 432 and the conductive layer 433b. The impurity semiconductor layer 432 and the conductive layer 435 are provided in contact with each other. 3a or the conductive layer 433b.

[0269] The semiconductor layer 432 can be made of, for example, a semiconductor containing silicon. Examples of semiconductors that can be used include hydrogenated amorphous silicon, microcrystalline silicon, and polycrystalline silicon. In particular, when hydrogenated amorphous silicon is used, The display device according to one embodiment of the present invention is preferably a display device having a field effect transistor. Even in transistors that use amorphous silicon, which has a relatively low mobility, It is possible to display the

[0270] Alternatively, an organic material may be used for the semiconductor layer 432. The above-mentioned electron transporting materials and hole transporting materials can be used. Polymer compounds such as poly-paraphenylene vinylene and polydiacetylene can also be used. However, the organic matter is not limited to this.

[0271] The impurity semiconductor film constituting the impurity semiconductor layer 435 is doped with an impurity element that imparts one conductivity type. When the transistor is an n-channel type, one conductivity type is As an example of a semiconductor doped with an impurity element, silicon doped with P or As is Alternatively, when the transistor is a p-channel type, one conductivity type is given. It is possible to add an impurity element such as B, but the transistor is an n-channel The impurity semiconductor layer may be formed of an amorphous semiconductor. Alternatively, the impurity semiconductor layer 43 may be formed using a crystalline semiconductor such as a microcrystalline semiconductor. 5. A composite material comprising the transition metal shown in the first embodiment and an organic compound having an unshared electron pair. can be preferably used.

[0272] The transistor shown in FIG. 7B has a semiconductor layer 432 and an impurity semiconductor layer 435 between them. The body layer 437 is

[0273] The semiconductor layer 437 may be formed of a semiconductor film similar to that of the semiconductor layer 432. The impurity semiconductor layer 437 is formed by etching the semiconductor layer 432 when the impurity semiconductor layer 435 is etched. The insulating layer can function as an etching stopper to prevent the insulating layer from being lost due to etching. In addition, in FIG. 7A, an example in which the semiconductor layer 437 is separated into left and right sides is shown. A part of the conductor layer 437 may cover a channel formation region of the semiconductor layer 432 .

[0274] The semiconductor layer 437 may contain a lower concentration of impurities than the impurity semiconductor layer 435. This allows the semiconductor layer 437 to be treated as a lightly doped drain (LDD). ) region, which reduces hot carrier degradation when the transistor is operated. It is possible to suppress the degradation.

[0275] In the transistor shown in FIG. 7C, an insulating layer 48 is provided over a channel formation region of a semiconductor layer 432. The insulating layer 484 is provided to prevent etching during etching of the impurity semiconductor layer 435. It acts as a stopper.

[0276] The transistor shown in FIG. 7D has a semiconductor layer 432p instead of the semiconductor layer 432. The semiconductor layer 432p includes a semiconductor film having high crystallinity. This allows the transistor to have high field-effect mobility. It is possible.

[0277] In the transistor shown in FIG. 7E, a semiconductor layer 432 is formed in a channel formation region of the semiconductor layer 432. For example, the transistor shown in FIG. It is formed by irradiating a region with laser light or the like to crystallize it locally. This makes it possible to realize a transistor with high field effect mobility.

[0278] The transistor shown in FIG. 7F has a structure similar to that of the semiconductor layer 432 of the transistor shown in FIG. A crystalline semiconductor layer 432p is provided in a channel formation region.

[0279] The transistor shown in FIG. 7G has a structure similar to that of the semiconductor layer 432 of the transistor shown in FIG. A crystalline semiconductor layer 432p is provided in a channel formation region.

[0280] The components included in the transistor will be described in detail below.

[0281] The transistor includes a conductive layer functioning as a gate electrode, a semiconductor layer functioning as a source electrode, and a A conductive layer serving as a drain electrode and an insulating layer serving as a gate insulating layer are provided. and an edge layer.

[0282] Note that the structure of a transistor included in a display device of one embodiment of the present invention is not particularly limited. For example, a planar type transistor or a staggered type transistor may be used. Alternatively, the transistor may be a top-gate type or a bottom-gate type. Alternatively, gate electrodes may be provided above and below the channel. It may be possible to do so.

[0283] The crystallinity of the semiconductor material used in the transistor is not particularly limited. A semiconductor having crystallinity (microcrystalline semiconductor, polycrystalline semiconductor, single crystal semiconductor, or semiconductor with partially crystalline regions) If a semiconductor having crystallinity is used, the This is preferable because it is possible to suppress deterioration of the resistor characteristics.

[0284] The semiconductor in which the transistor channel is formed can be, for example, silicon. As the silicon, it is particularly preferable to use amorphous silicon. By using silicon, transistors can be formed on large substrates with good yield, and it has excellent mass productivity. can be.

[0285] In addition, silicon having crystallinity such as microcrystalline silicon, polycrystalline silicon, and single crystal silicon In particular, polycrystalline silicon can be formed at a lower temperature than single crystal silicon. It also has higher field effect mobility and higher reliability than amorphous silicon.

[0286] The bottom-gate transistor described in this embodiment can reduce the manufacturing process. In addition, the use of amorphous silicon at this time is preferable because it is less expensive than polycrystalline silicon. Since it can be formed at low temperatures, it is suitable for use as a material for wiring and electrodes below the semiconductor layer, and as a material for substrates. This allows the use of materials with low thermal conductivity, which broadens the range of material choices. For example, In this case, a glass substrate having a very large area can be preferably used. Since the impurity region of a transistor can be easily formed in a self-aligned manner, the variation in characteristics can be reduced. In this case, it is preferable to use polycrystalline silicon or single crystal silicon. It may be appropriate to use

[0287] <Substrate> There is no particular restriction on the material of the substrate 411, but it should be strong enough to withstand the subsequent heat treatment. For example, glass substrates, ceramic substrates, quartz substrates, and sa A fire substrate or the like may be used as the substrate 411. Also, a material such as silicon or silicon carbide may be used. Single crystal semiconductor substrates, polycrystalline semiconductor substrates, compound semiconductors such as silicon germanium, etc. It is also possible to use a substrate, an SOI substrate, or the like, on which a semiconductor element is provided. The substrate 411 may be a glass substrate. If you have 6th generation (1500mm x 1850mm), 7th generation (1870mm x 220 0mm), 8th generation (2200mm x 2400mm), 9th generation (2400mm x 280 By using large area substrates such as 10th generation (2950mm x 3400mm) and 10th generation (2950mm x 3400mm), By using such a large-area substrate, a large display device can be manufactured. This is preferable because it can reduce costs.

[0288] In addition, a flexible substrate is used as the substrate 411, and the transistor is directly formed on the flexible substrate. Alternatively, a peeling layer may be provided between the substrate 411 and the transistor. The peeling layer is used to separate the transistor from the substrate 411 after the transistor is partially or completely completed thereon. The transistor can be separated from the substrate and transferred to another substrate. It can be transferred to substrates with poor mechanical properties or flexible substrates.

[0289] <Conductive layer> Materials that can be used for the gate, source, and drain of a transistor include aluminum. Minium, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, Examples include metals such as silver, tantalum, or tungsten, or alloys that contain these metals as their main components. In addition, films containing these materials can be used as a single layer or a laminate structure. For example, a single layer structure of an aluminum film containing silicon, an aluminum film on a titanium film, Two-layer structure with a tungsten film on top of an aluminum film; copper-magnesium film on top of a tungsten film A two-layer structure in which a copper film is laminated on a sodium-aluminum alloy film, and a copper film is laminated on a titanium film Two-layer structure, a two-layer structure in which a copper film is laminated on a tungsten film, a titanium film or a titanium nitride film An aluminum film or a copper film is laminated on top of the aluminum film, and a titanium film or a nitride film is further laminated on top of the aluminum film. A three-layer structure that forms a titanium oxide film, a molybdenum film or a molybdenum nitride film, and a layer An aluminum film or a copper film is laminated on the substrate, and a molybdenum film or a molybdenum nitride film is further laminated on the aluminum film or a copper film. In addition, oxides such as indium oxide, tin oxide, and zinc oxide are used. Also, when copper containing manganese is used, it is possible to control the shape by etching. This is preferable because it increases the efficiency.

[0290] In addition, a light-transmitting material that can be used for the gate, source, and drain of a transistor is The conductive materials that can be used are indium oxide, indium tin oxide, and indium zinc oxide. , zinc oxide, zinc oxide doped with gallium, or other conductive oxides, or graphene. Or gold, silver, platinum, magnesium, nickel, tungsten, chromium Metallic materials such as molybdenum, iron, cobalt, copper, palladium, or titanium, or the metals An alloy material containing the metal can be used. Alternatively, a nitride of the metal material (e.g., nitride Titanium) may be used. Metal materials, alloy materials (or their nitrides) may be used. In the case where the conductive layer is a conductive layer, the conductive layer may be thin enough to have light-transmitting properties. For example, a silver-magnesium alloy and indium tin oxide can be used. It is preferable to use a laminated film or the like because it is possible to increase the electrical conductivity. Conductive layers such as various wirings and electrodes constituting the display device, and conductive layers (pixel electrodes and common electrodes) of the display device It can also be used as a conductive layer that functions as an electrode.

[0291] <Insulating layer> Examples of insulating materials that can be used for each insulating layer include resins such as acrylic and epoxy. In addition to resins with siloxane bonds such as silicone and silicone, silicon oxide, silicon oxynitride, Inorganic insulating materials such as silicon nitride oxide, silicon nitride, and aluminum oxide are used. It is also possible.

[0292] Insulating films with low water permeability include those containing nitrogen and silicon, such as silicon nitride film and silicon oxynitride film. Examples of the film include a film containing nitrogen and aluminum, such as an aluminum nitride film. Alternatively, a silicon nitride film, a silicon oxynitride film, an aluminum oxide film, or the like may be used.

[0293] Note that various films such as a conductive film, an insulating film, and a semiconductor film included in the transistor described in this embodiment are Various films are deposited by sputtering, chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PE) and It can be formed using chemical vapor deposition (CVD), vacuum evaporation, or pulsed laser deposition (PLD). However, the present invention is not limited to these, and examples of the method include coating method, printing method, and thermal CVD (Chemical Vapor Deposition). Vapor Deposition (ALD) or Atomic Layer Deposition (ALD) As an example of a thermal CVD method, MO CVD(Metal Organic Chemical Vapor Deposit) A conductive film, an insulating film, a semiconductor film, or the like may be formed by using a deposition method or the like.

[0294] (Embodiment 5) In this embodiment, an electronic device according to one embodiment of the present invention will be described.

[0295] One embodiment of the present invention is a light-emitting element using an organic electroluminescence (EL), which has a flat surface and has good luminous efficiency. In addition, according to one embodiment of the present invention, a light-emitting device having a curved surface can be manufactured. Efficient and reliable electronic devices can be created.

[0296] Examples of electronic devices include television sets, desktop or notebook PCs, etc. Computers, monitors for computers, digital cameras, digital video cameras Cameras, digital photo frames, mobile phones, portable game consoles, personal digital assistants, audio playback Examples of such devices include large gaming machines such as pachinko machines.

[0297] A portable information terminal 900 shown in FIGS. 8A and 8B includes a housing 901, a housing 902, a display unit 90 3, and a hinge portion 905.

[0298] The housing 901 and the housing 902 are connected by a hinge portion 905. The mobile information terminal 900 includes: It can be unfolded from the folded state (FIG. 8(A)) to the state shown in FIG. 8(B). This makes it highly portable when you carry it around, and when you use it, the large display area makes it easy to see. Excellent recognition.

[0299] The portable information terminal 900 has a housing 901 and a housing 902 connected by a hinge portion 905. A flexible display unit 903 is provided.

[0300] A light-emitting device manufactured according to one embodiment of the present invention can be used for the display portion 903. This makes it possible to manufacture portable information terminals with a high yield.

[0301] The display unit 903 is capable of displaying at least one of document information, still images, and moving images. When document information is displayed on the display unit, the portable information terminal 900 is used as an electronic book terminal. It can be used as such.

[0302] When the portable information terminal 900 is unfolded, the display portion 903 is held in a largely curved state. For example, the radius of curvature is 1 mm or more and 50 mm or less, preferably 5 mm or more and 30 mm or less. The display unit 903 is supported by the housing 901 and the cover 902. Pixels are continuously arranged from 902 to 902, enabling a curved display.

[0303] The display unit 903 functions as a touch panel and can be operated by a finger, a stylus, etc. can.

[0304] It is preferable that the display unit 903 is composed of one flexible display. This makes it possible to perform continuous display without interruption between the housing 901 and the housing 902. In addition, a display may be provided in each of the housings 901 and 902. You may do so.

[0305] The hinge portion 905 is a portion that connects the housing 901 and the housing 902 when the mobile information terminal 900 is unfolded. It is preferable to have a locking mechanism to prevent the angle from becoming larger than a predetermined angle. For example, the angle at which the door will lock (will not open any further) must be greater than 90 degrees and less than 180 degrees. Typically, the angle is 90 degrees, 120 degrees, 135 degrees, 150 degrees, or 17 degrees. 5 degrees, etc. This improves the convenience, safety, and Reliability can be improved.

[0306] If the hinge portion 905 has a locking mechanism, the display portion 903 can be opened without applying excessive force. Therefore, it is possible to prevent the display unit 903 from being damaged. It can be achieved.

[0307] The housing 901 and the housing 902 are provided with a power button, an operation button, an external connection port, a speaker, a microphone, and the like. It may have an indentation or the like.

[0308] A wireless communication module is provided in either the housing 901 or the housing 902. Internet, LAN (Local Area Network), Wi-Fi (registered trademark ) and the like.

[0309] A portable information terminal 910 shown in FIG. 8C includes a housing 911, a display unit 912, and an operation button 913. , an external connection port 914, a speaker 915, a microphone 916, a camera 917, etc.

[0310] A light-emitting device manufactured according to one embodiment of the present invention can be used for the display portion 912. This makes it possible to manufacture portable information terminals with a high yield.

[0311] The mobile information terminal 910 has a touch sensor on the display unit 912. All operations, such as inputting characters, can be performed by touching the display 912 with a finger or a stylus. It can be done.

[0312] In addition, the operation button 913 is operated to turn the power on and off, and to display on the display unit 912. For example, you can change the type of image displayed on the main screen from the email composition screen. You can switch to the menu screen.

[0313] In addition, a detection device such as a gyro sensor or an acceleration sensor is provided inside the portable information terminal 910. By providing the above, the orientation of the mobile information terminal 910 (vertical or horizontal) can be determined and the screen of the display unit 912 can be adjusted. The display orientation can be switched automatically. The screen orientation can also be switched by The input is made by touching the display unit 912, by operating the operation button 913, or by inputting voice using the microphone 916. It can also be performed by using force or the like.

[0314] The mobile information terminal 910 is, for example, one or more devices selected from a telephone, a notebook, an information viewing device, etc. Or it has multiple functions. Specifically, it can be used as a smartphone. The information terminal 910 is, for example, a mobile phone, an e-mail, a document viewing and creation, a music playback, a video It can run various applications such as playback, internet communication, and games. do.

[0315] The camera 920 shown in FIG. 8D includes a housing 921, a display unit 922, an operation button 923, and a shutter. The camera 920 also has a detachable lens 926. It is attached.

[0316] The light-emitting device manufactured according to one embodiment of the present invention can be used for the display portion 922. This makes it possible to create a camera with low power consumption.

[0317] Here, the camera 920 and the lens 926 can be removed from the housing 921 and replaced. However, the lens 926 and the housing 921 may be integrated together.

[0318] The camera 920 captures still or moving images by pressing the shutter button 924. In addition, the display unit 922 has a function as a touch panel. It is also possible to capture an image by touching the

[0319] The camera 920 can be equipped with a strobe device, viewfinder, etc. Alternatively, these may be incorporated into the housing 921.

[0320] 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.

[0321] The mobile information terminal 9200 shown in FIG. 9A is capable of performing a variety of functions, including mobile phone, e-mail, document viewing and creation, It can be used for various applications such as music playback, internet communication, and computer games. In addition, the display surface of the display unit 9001 is curved, and the curved The portable information terminal 9200 can display information on the display surface. For example, it is possible to use a wireless headset to perform short-distance wireless communication. By communicating with each other, you can talk hands-free. 200 has a connection terminal 9006 and can directly exchange data with other information terminals via a connector. It is also possible to charge the battery via the connection terminal 9006. The charging operation may be performed by wireless power supply without going through the connection terminal 9006.

[0322] 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)).

[0323] 9(C) to (E) are perspective views showing a foldable portable information terminal 9202. FIG. 9C is a perspective view of the portable information terminal 9202 in an unfolded state, and FIG. The portable information terminal 9202 is in the process of changing from one of the unfolded state and the folded state to the other. 9(E) is a perspective view of the portable information terminal 9202 in a folded state. be.

[0324] The portable information terminal 9202 is highly portable when folded, and has a seam when unfolded. The display area of ​​the portable information terminal 9202 is large and has excellent visibility. 9001 is supported by three housings 9000 connected by hinges 9055 . The two housings 9000 are bent via the hinge 9055, so that the portable information terminal 9 202 can be reversibly transformed from an unfolded state to a folded state. For example, The portable information terminal 9202 can be bent with a radius of curvature of 1 mm or more and 150 mm or less.

[0325] This embodiment mode can be combined with other embodiment modes as appropriate.

[0326] (Embodiment 6) In this embodiment, an example in which the light-emitting element of one embodiment of the present invention is applied to various lighting devices will be described. 10 and 11. By using a light-emitting element which is one embodiment of the present invention, Thus, a highly reliable lighting device with good luminous efficiency can be manufactured.

[0327] The light-emitting element of one embodiment of the present invention can be fabricated over a flexible substrate to have a curved surface. It is possible to realize electronic devices and lighting devices having a light-emitting region.

[0328] In addition, a light-emitting device using a light-emitting element according to one embodiment of the present invention can be used for automobile lighting. For example, lighting can be installed on the windshield, ceiling, etc.

[0329] FIG. 10(A) shows a perspective view of one side of a multifunction terminal 3500, and FIG. 3 shows a perspective view of the other side of the multi-function terminal 3500. 2 incorporates a display unit 3504, a camera 3506, and lighting 3508. The light emitting device of the embodiment can be used for lighting 3508.

[0330] The light emitting device according to one embodiment of the present invention is used for the light source 3508, and the light source 3508 functions as a surface light source. Therefore, unlike point light sources such as LEDs, light with little directionality can be obtained. For example, when the lighting 3508 and the camera 3506 are used in combination, the lighting 3508 is turned on. The camera 3506 can capture the image by turning the light on or off. Because it functions as a surface light source, it is possible to take photos that look like they were taken under natural light. Cut.

[0331] The multifunction terminal 3500 shown in FIGS. 10(A) and 10(B) is similar to the multifunction terminal 3500 shown in FIGS. 9(A) to 9(C). As with the electronic device shown in FIG.

[0332] In addition, inside the housing 3502, a speaker, a sensor (force, displacement, position, speed, acceleration, angle Speed, rotation speed, distance, light, liquid, magnetism, temperature, chemicals, sound, time, hardness, electric field, current, Includes functions to measure voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays The multifunction terminal 3500 may have a built-in speaker, a microphone, etc. By providing a detection device having a sensor that detects the inclination, such as a gyro or acceleration sensor, The screen display of the display unit 3504 is automatically adjusted by determining the orientation (portrait or landscape) of the functional terminal 3500. It is possible to make it switchable.

[0333] The display unit 3504 can also function as an image sensor. By touching the palm or fingers to the sensor 504 and capturing an image of the palm print, fingerprint, or the like, personal authentication can be performed. In addition, the display unit 3504 may be provided with a backlight that emits near-infrared light or a sensor that emits near-infrared light. If a light source for imaging is used, finger veins, palm veins, etc. can also be imaged. The light-emitting device according to one embodiment of the present invention may be applied to the above-mentioned embodiment 04.

[0334] FIG. 10C shows a perspective view of a security light 3600. The light 3600 is The housing 3602 has a light 3608 on the outside, and the housing 3602 is equipped with a speaker 3610 and the like. The light-emitting element of one embodiment of the present invention can be used for the lighting 3608.

[0335] Light 3600 may, for example, be a device that grasps, holds, or holds light 3608. The inside of the housing 3602 is provided with a light 3600. The light emitting device may be provided with an electronic circuit that can control the light emitting method. Alternatively, the circuit may be such that light can be emitted intermittently multiple times, or the light emission current value may be controlled. The circuit may be configured so that the amount of light emitted can be adjusted by adjusting the amount of light emitted from the light source 3608. At the same time, a circuit may be incorporated to output a loud alarm sound from the speaker 3610. stomach.

[0336] The Light 3600 can emit light in any direction, so it can be used to target, for example, thugs. The Light 3600 can also be equipped with a digital sensor to scare off predators. It may also be equipped with a camera such as a still camera, or a function having a shooting function.

[0337] FIG. 11 shows an example in which the light-emitting element is used as an indoor lighting device 8501. Since the surface area can be increased, a large-area lighting device can be formed. By using a housing having such a curved light-emitting area, a lighting device 8502 can be formed. The light-emitting element shown in this embodiment mode has a thin film shape, and the design of the housing has a high degree of freedom. Therefore, it is possible to form lighting devices with various elaborate designs. A large lighting device 8503 may be provided on the wall. A touch sensor may be provided in 503 to turn the power on or off.

[0338] In addition, by using light-emitting elements on the surface of the table, it has the function of a table. The lighting device 8504 can be used as a lighting device. This makes it possible to provide a lighting device that also functions as furniture.

[0339] In this manner, a lighting device and an electronic device can be obtained by using the light-emitting device of one embodiment of the present invention. Note that the lighting devices and electronic devices to which the present invention can be applied are the same as those described in this embodiment. The present invention can be applied to electronic devices in a wide range of fields.

[0340] The structure described in this embodiment may be used in appropriate combination with structures described in other embodiments. There can be. EXAMPLES

[0341] In this example, light-emitting elements 2 to 4 which are light-emitting elements of one embodiment of the present invention and A comparative example of the fabrication of a comparative light-emitting element 1 is shown. The details of the element structure are shown in FIG. 12 and Table 4. The chemical formula is shown below. For the structures and abbreviations of other compounds, please refer to the first embodiment. Just pour some drinks.

[0342] [ka]

[0343] [Table 4]

[0344] In addition, the LUMO levels of the organic compounds used in the electron injection layers 130 of the light-emitting elements 2 to 4 was calculated by cyclic voltammetry (CV) measurements.

[0345] The measurement device used was an electrochemical analyzer (manufactured by BAS Co., Ltd., model number: ALS model). The solution used in the CV measurements was dehydrated dimethyl ether. Dimethylformamide (DMF) (Aldrich Co., Ltd., 99.8%, Catalog No. 227 05-6) was used as the supporting electrolyte, tetra-n-butylammonium perchlorate (nB u4NClO4) (Tokyo Chemical Industry Co., Ltd., catalog number: T0836) was added at 100 mmol / The measurement target was then dissolved in water to a concentration of 2 mmol / L. The working electrode was a platinum electrode (PT E platinum electrode) as an auxiliary electrode, and a platinum electrode (B.A.S. Co., Ltd., VC-3 P t counter electrode (5 cm)) and Ag / Ag as the reference electrode. + Electrode (B.A.E. The measurements were performed at room temperature (20°C). The scan speed during CV measurement was kept constant at 0.1 V / sec. The oxidation potential Ea [V] and reduction potential Ec [V] against the reference electrode were measured. is the midpoint potential of the oxidation-reduction wave, and Ec is the midpoint potential of the reduction-oxidation wave. The potential energy of the reference electrode used in this example relative to the vacuum level is -4.94 eV. Therefore, the HOMO level [eV] = -4.94-Ea, and the LUMO level From the formula, HOMO level and LUMO level are respectively This can be requested.

[0346] From the above measurements, the LUMO of NBPhen is -2.83 eV, and the LUMO of Alq3 is -2. The LUMO of 2mDBTBPDBq-II was calculated to be 80 eV, and the LUMO of 2mDBTBPDBq-II was calculated to be -2.94 eV.

[0347] <Fabrication of light-emitting element> The method for producing the light-emitting element produced in this example is described below. The light-emitting element 2 uses LiF, a Li compound that is commonly used in The light-emitting element 4 is an embodiment of the present invention, in which an organic compound having an unshared electron pair is used in an electron injection layer. This is a light-emitting element that uses a composite material of transition metals.

[0348] <Preparation of comparative light-emitting element 1> An ITSO film was formed as an electrode 101 on a substrate 210 to a thickness of 70 nm. The electrode area of ​​the electrode 101 is 4 mm 2 (2mm x 2mm).

[0349] Next, a hole injection layer 111 made of DBT3P-II and molybdenum oxide ( MoO3) in a weight ratio (DBT3P-II:MoO3) of 1:0.5, The layers were co-evaporated to a thickness of 65 nm.

[0350] Next, as the hole transport layer 112 on the hole injection layer 111, BPAFLP was deposited to a thickness of 20 nm. The deposition was carried out as follows.

[0351] Next, on the hole transport layer 112, 2mDBTBPDBq-II and P CBBiF and bis{4,6-dimethyl-2-[5-(2,6-dimethylphenyl)-3- (3,5-dimethylphenyl)-2-pyrazinyl-κN]phenyl-κC}(2,2', 6,6'-Tetramethyl-3,5-heptanedionato-κ 2 O,O') Iridium(II I) (abbreviation: Ir(dmdppr-dmp)2(dpm)) and the weight ratio (2mDBTB PDBq-II:PCBBiF:Ir(dmdppr-dmp)2(dpm)) is 0.7 The mixture was co-evaporated to a thickness of 40 nm in a ratio of 5:0.25:0.06. In the light-emitting layer 140, 2mDBTBPDBq-II and PCBBiF are host materials. and Ir(dmdppr-dmp)2(dpm) is the guest material (phosphorescent compound). do.

[0352] Next, 2mDBTBPDBq-II was added as the electron transport layer 118(1) on the light-emitting layer 140. was evaporated to a thickness of 25 nm.

[0353] Next, NBPhen was deposited to a thickness of 118(1) as the electron transport layer 118(2). The deposition was carried out so that the thickness was 20 nm.

[0354] On the electron transport layer 118(2), lithium fluoride (LiF) is deposited as an electron injection layer 130. The deposition was carried out so that the thickness was 1 nm.

[0355] Next, on the electron injection layer 130, aluminum (Al) was deposited to a thickness of 20 The deposition was carried out so as to obtain a thickness of 0 nm.

[0356] Next, without sealing, the device was heat-treated in air at 80°C for 1 hour. Optical element 1 was obtained.

[0357] <Fabrication of light-emitting element 2> The light-emitting element 2 was fabricated in the same manner as the comparative light-emitting element 1 described above, except that the electron transport layer 118(2) and the electron injection layer 118(3) were The only difference is the process of forming the insulating layer 130, and the other processes are the same as those of the comparative light-emitting element 1. did.

[0358] As the electron transport layer 118(2) of the light-emitting element 2, NBPhe was deposited on the electron transport layer 118(1). n was evaporated to a thickness of 10 nm.

[0359] On the electron transport layer 118(2), an electron injection layer 130 was formed by depositing NBPhen and Ag in a weight ratio of ( NBPhen:Ag) was co-evaporated at a ratio of 1:0.38 to a thickness of 10 nm.

[0360] <Fabrication of Light-emitting Device 3 and Light-emitting Device 4> The light-emitting element 3 and the light-emitting element 4 were fabricated by the same process as that of the light-emitting element 2 described above, and the formation of the electron injection layer 130. The manufacturing method was the same as that for the light-emitting element 2, except for the manufacturing process.

[0361] <Fabrication of Light-emitting Device 3> The electron injection layer 130 was formed on the electron transport layer 118(2) of the light-emitting element 3 by using Alq3 and Ag. The Alq3:Ag weight ratio was 1:0.48 and the thickness was 10 nm. .

[0362] <Fabrication of Light-emitting Device 4> On the electron transport layer 118(2) of the light-emitting element 4, 2mDBTBPD was used as the electron injection layer 130. Bq-II and Ag were mixed in a weight ratio of 1:0.40 (2mDBTBPDBq-II:Ag), and The film was co-evaporated to a thickness of 10 nm.

[0363] <Characteristics of light-emitting element> Next, the element characteristics of the comparative light-emitting element 1 and the light-emitting elements 2 to 4 prepared above were measured. A color luminance meter (Topcon, BM-5A) was used to measure luminance and CIE chromaticity. The electroluminescence spectrum was measured using a multichannel spectrometer (Hamamatsu Photonics, PMA- 11) was used.

[0364] FIG. 13 shows the current efficiency vs. luminance characteristics of the fabricated comparative light-emitting element 1 and light-emitting elements 2 to 4. The current density-voltage characteristics are shown in Fig. 14, the power efficiency-luminance characteristics in Fig. 15, and the external quantum efficiency-luminance characteristics in Fig. 16. The characteristics are shown in Figure 16. The measurements of each light-emitting element were performed at room temperature (in an atmosphere maintained at 23°C). ) was applied to each light-emitting device. 2 The electric field when a current is passed with a current density of The emission spectrum is shown in Figure 17. The measurement was carried out at room temperature.

[0365] Also, 1000cd / m 2 Comparative light-emitting element 1 and light-emitting element 2 to The device characteristics of 4 are shown in Table 5.

[0366] [Table 5]

[0367] As shown in FIG. 16 and Table 5, the comparative light-emitting element 1 and the light-emitting elements 2 to 4 each have The external quantum efficiency exceeded 20%, and the luminous efficiency was high. As shown in Figs. The comparative light-emitting element 1 and the light-emitting elements 2 to 4 all have high current efficiency and power efficiency. In particular, the comparative light-emitting element 1, the light-emitting element 2, and the light-emitting element 4 exhibited external quantum efficiencies of 25%. In addition, the light-emitting element 2 and the light-emitting element according to one embodiment of the present invention 4 is equivalent to the comparative light-emitting element 1, which uses LiF, a material commonly used for the electron injection layer. showed high efficiency.

[0368] As shown in FIG. 14, the comparative light-emitting element 1 and the light-emitting elements 2 to 4 have good current In particular, the light-emitting element 2 had current density-voltage characteristics equivalent to those of the comparative light-emitting element 1. The composite of NBPhen and Ag has excellent electron injection properties. I understand.

[0369] As shown in FIG. 17, the electric field emission of the comparative light-emitting element 1 and the light-emitting elements 2 to 4 is The peak wavelength of the optical spectrum is around 619 nm, and the full width at half maximum is 58 nm. m, red light emission was observed. From the obtained electroluminescence spectrum, the guest material I It was found that the emission was from r(dmdppr-dmp)2(dpm).

[0370] <Evaluation of Reliability of Light-Emitting Device> Next, the comparative light-emitting element 1 and the light-emitting elements 2 to 4 were subjected to a constant temperature and humidity storage test. Since each light-emitting element is not sealed, the cathode and EL layer are exposed to the atmosphere of the test environment. Generally, when moisture gets into a light-emitting element, dark spots (areas inside the light-emitting section) appear. The non-light-emitting area at the edge of the light-emitting part) or shrinkage (non-light-emitting area at the edge of the light-emitting part) occurs. This adversely affects the reliability of the element. The reliability against moisture can be evaluated.

[0371] The comparative light-emitting element 1 and the light-emitting elements 2 to 4 were each exposed to light at a temperature of 65° C. and a humidity of 95%. After leaving them in a thermostatic chamber for 48 hours, the light emission state of each light-emitting element was investigated. Ta.

[0372] The luminous state was evaluated by estimating the ratio of the luminous area before and after the constant temperature and humidity storage test. The results are shown in Table 6.

[0373] [Table 6]

[0374] In Table 6, the luminous area ratio (%) = luminous area after constant temperature and humidity storage test / luminous area before constant temperature and humidity test From Table 6, the ratio of LiF, an alkali metal compound, used in the electron injection layer is Light-emitting elements 2 to 4, which are light-emitting elements according to one embodiment of the present invention, are used instead of the comparative light-emitting element 1. In other words, the light-emitting element according to one embodiment of the present invention has a large light-emitting area ratio. In contrast, light-emitting devices that use materials with small work functions, such as alkali metals, in the electron injection layer have higher resistance to ultraviolet radiation. This is because materials with a small work function have high reactivity with water and low radiative release. This is because moisture enters the inside of the optical element. Since transition metals that are poorly reactive with water are used, moisture is less likely to penetrate into the inside of the light-emitting element. Therefore, a light emitting element having high moisture resistance can be realized.

[0375] <Absorption spectrum of composite material of organic compound and transition metal> Next, a thin film of the composite material of the organic compound and Ag used in the electron injection layer of the light-emitting elements 2 to 4 was The absorption spectrum of the Ag thin film and the organic compound thin film were also measured. The results are shown in Figures 18 to 20. Thin film of a composite material of an organic compound and Ag The organic compound was deposited on a quartz substrate with a molar ratio (organic compound:Ag) of 1:1 and a thickness of 50 nm. The organic compound thin film was formed by vacuum deposition on a quartz substrate. The Ag thin film was formed by vacuum deposition to a thickness of 50 nm. The Ag thin film was formed by vacuum deposition to a thickness of 2 nm. The amount of Ag in the organic compound-Ag composite thin film with a thickness of 50 nm is The amount of Ag in the sample is approximately the same as that of Ag in the sample. A spectrophotometer (U4100, manufactured by Electoron Technologies) was used.

[0376] 18 to 20, the Ag thin film emits surface plasmons specific to metal thin films at around 450 nm. On the other hand, the surface plasmon peak was observed from the composite material of the organic compound and Ag. Surface plasmons are observed in very small (nano) structures such as thin metal films and metal nanoparticles. Therefore, in the organic compound-Ag composite, Therefore, Ag is not an aggregate of Ag atoms such as Ag thin films or Ag nanoparticles, but exists as Ag atoms. This suggests that the molecules exist in a state where they interact with organic compounds. In the mixed film, the organic compound and the transition metal Ag interact with each other. It can be said that this is the state in which

[0377] As described above, the light-emitting element of one embodiment of the present invention has excellent electron injection properties and therefore requires low driving voltage. In addition, since a material with a low work function is not used, the light-emitting element has high light-emitting efficiency. The structure shown in this embodiment may be appropriately combined with other embodiments and embodiment modes. They can be used in combination. EXAMPLES

[0378] In this example, a light-emitting element 6 which is a light-emitting element of one embodiment of the present invention and a comparative light-emitting element An example of the fabrication of element 5 is shown in FIG. 12, which shows a schematic cross-sectional view of the light-emitting element fabricated in this example. The details are shown in Table 7. The structures and abbreviations of the compounds used are shown below. For the structures and abbreviations of other compounds, the above examples and embodiments may be referred to.

[0379] [ka]

[0380] [Table 7]

[0381] In addition, the LUMO level of 4mCzBPBfpm used in the electron injection layer 130 of the light-emitting element 6 was The calculation was performed by cyclic voltammetry (CV) measurement. The measurement method was the same as in Example 1. I did it in a way.

[0382] As a result, the LUMO of 4mCzBPBfpm is -2.83 eV, and the LUMO of Alq3 is - The calculated value was 2.97 eV.

[0383] <Fabrication of light-emitting element> A method for fabricating the light-emitting element in this embodiment will be described below. The comparative light-emitting element 5 has a single layer, and LiF, a Li compound that is generally used in the electron injection layer. The light-emitting element 6 is an embodiment of the present invention, in which a non-shared electron The light-emitting element is a composite material of an organic compound having a pair and a transition metal. Light-emitting device using an organic compound having a pyrimidine ring as an organic compound having a shared electron pair Here is an example:

[0384] <Preparation of Comparative Light-Emitting Element 5> An ITSO film was formed as an electrode 101 on a substrate 210 to a thickness of 70 nm. The electrode area of ​​the electrode 101 is 4 mm 2 (2mm x 2mm).

[0385] Next, DBT3P-II and MoO3 were laminated on the electrode 101 as the hole injection layer 111. The ratio of the amount of DBT3P-II to MoO3 was 1:0.5, and the thickness was 70 nm. The mixture was co-evaporated so as to obtain a

[0386] Next, as the hole transport layer 112 on the hole injection layer 111, BPAFLP was deposited to a thickness of 20 nm. The deposition was carried out as follows.

[0387] Next, 4mCzBPBfpm and PCBBi were deposited on the hole transport layer 112 as the light emitting layer 140. F and Ir(dmdppr-dmp)2(dpm) and the weight ratio (4mCzBPBfpm: PCBBiF:Ir(dmdppr-dmp)2(dpm)) is 0.75:0.25:0 The luminescent layer 140 was co-deposited to a thickness of 40 nm. In this study, 4mCzBPBfpm and PCBBiF are the host materials, and Ir(dmdp pr-dmp)2(dpm) is the guest material (phosphorescent compound).

[0388] Next, 4mCzBPBfpm was deposited on the light-emitting layer 140 to form the electron transport layer 118 with a thickness of 40 The deposition was carried out so as to give a thickness of nm.

[0389] On the electron transport layer 118, an electron injection layer 130 was formed by depositing lithium fluoride (LiF) to a thickness of 1 The deposition was carried out so as to give a thickness of nm.

[0390] Next, on the electron injection layer 130, aluminum (Al) was deposited to a thickness of 20 The deposition was carried out so as to obtain a thickness of 0 nm.

[0391] Next, without sealing, the device was heat-treated in air at 80°C for 1 hour. Optical element 5 was obtained.

[0392] <Fabrication of light-emitting element 6> The light-emitting element 6 was fabricated in the same manner as the comparative light-emitting element 5 described above, except that the electron transport layer 118 and the electron injection layer 1 The only difference was the formation process of 30, and the other processes were the same as those of the comparative light-emitting element 5.

[0393] As the electron transport layer 118 of the light-emitting element 6, 4mCzBPBfpm was deposited on the light-emitting layer 140 to a thickness of The deposition was carried out so that the thickness was 25 nm.

[0394] On the electron transport layer 118, an electron injection layer 130 was formed by depositing 4mCzBPBfpm and Ag in a weight ratio. (4mCzBPBfpm:Ag) was co-evaporated to 1:0.22 and the thickness was 15 nm. I arrived.

[0395] <Characteristics of light-emitting element> Next, the element characteristics of the comparative light-emitting element 5 and the light-emitting element 6 prepared above were measured. The same procedure was followed as in Example 1 described above.

[0396] FIG. 21 shows the current efficiency-luminance characteristics of the fabricated comparative light-emitting element 5 and light-emitting element 6. The characteristics are shown in Fig. 22, the power efficiency vs. luminance characteristics in Fig. 23, and the external quantum efficiency vs. luminance characteristics in Fig. 24. Each light-emitting element was supplied with 2.5 mA / cm 2 The electric field when a current is passed with a current density of The emission spectrum is shown in FIG.

[0397] Also, 1000cd / m 2 The element characteristics of the comparative light-emitting element 5 and the light-emitting element 6 in the vicinity Shown in Table 8.

[0398] [Table 8]

[0399] As shown in FIG. 22, compared with the comparative light-emitting element 5, the light-emitting element 6 has a better current density-voltage This is a device that uses the host material of the light-emitting layer as an electron transport layer, and When the structure is such that the electron injection layer is in contact with the light-transmitting layer, the It was shown that the light-emitting element according to one embodiment of the present invention has a better electron injection property than the light-emitting element according to one embodiment of the present invention. is.

[0400] As shown in FIGS. 21, 23, and 24 and Table 8, the light-emitting element 6 is better than the comparative light-emitting element 5. showed good luminous efficiency (current efficiency, power efficiency, and external quantum efficiency). As shown above, the light-emitting element 6 has a better electron injection property than the comparative light-emitting element 5, and thus the carrier dispersion This indicates that the performance is good.

[0401] As shown in FIG. 25, the electroluminescence spectra of the comparative light-emitting element 5 and the light-emitting element 6 are The peak wavelengths are all around 616 nm, and the full width at half maximum is all 53 nm. The obtained electroluminescence spectrum showed that the guest material Ir(dmdpp It was found that the emission was from r-dmp)2 (dpm).

[0402] Next, the driving life test was performed on the comparative light-emitting element 5 and the light-emitting element 6. The results are shown in Figure 43. The driving life test was performed at a current density of 25 mA / cm 2 To The light emitting elements were continuously driven under the condition of a constant current density.

[0403] As shown in FIG. 43, the light-emitting element 6 has a longer driving life than the comparative light-emitting element 5. , and showed excellent operating life.

[0404] That is, the light-emitting element having the electron-injection layer of one embodiment of the present invention exhibits excellent driving lifetime. It was a success.

[0405] <Absorption spectrum of composite material of organic compound and transition metal> Next, the absorption spectra of the composite material of 4mCzBPBfpm and Ag used in the electron injection layer of the light-emitting device 6 were The spectrum was measured. The results are shown in Figure 26. The sample preparation method and measurement method were as described above. The same procedure as in Example 1 was carried out.

[0406] As shown in Figure 26, the Ag thin film has a surface plasmon peak at around 450 nm, which is characteristic of thin metal films. On the other hand, as in Example 1, the composite material of 4mCzBPBfpm and Ag did not show the corresponding No surface plasmon peak was observed. Therefore, the composite of 4mCzBPBfpm and Ag The material is in a state where 4mCzBPBfpm and Ag interact in a thin film. I can say.

[0407] As described above, the light-emitting element of one embodiment of the present invention has a light-emitting layer in an electron-injection layer and an electron-transport layer. The same material as the host material is used, and it is also suitable for use in devices in which the electron injection layer and the electron transport layer are adjacent to each other. It was also found that a material having a pyrimidine ring can be suitably used. It has been found that the configuration shown in this embodiment can be appropriately combined with other embodiments and embodiments. It can be used in combination. EXAMPLES

[0408] In this example, light-emitting elements 8 to 10 which are light-emitting elements according to one embodiment of the present invention and their comparison FIG. 1 shows a schematic cross-sectional view of a light-emitting element fabricated in this example. The details of the device structure are shown in Table 12 and Table 9. The structures of the compounds used in this example are shown in Table 12 and Table 9, respectively. For the abbreviations and the like, the above examples and embodiments can be referred to.

[0409] [Table 9]

[0410] In addition, the LUMO standard of the organic compound used in the electron injection layer 130 of the light-emitting element 9 and the light-emitting element 10 is The potential was calculated by cyclic voltammetry (CV) measurement. The measurement method was the same as in Example 1. was carried out in a similar manner.

[0411] As a result, the LUMO of 2Py3Tzn is -3.15 eV, and the LUMO of TmPPPyTz is The calculated value was -3.00 eV.

[0412] <Fabrication of light-emitting element> The method for producing the light-emitting device in this example is described below. The light-emitting device is a light-emitting device using Li20, a Li compound that is commonly used in light-emitting devices. The light-emitting element 10 is an embodiment of the present invention, In this embodiment, a light-emitting element is formed by using a composite material of a metal and a transition metal. A light-emitting element using an organic compound having a triazine ring as the organic compound will be exemplified.

[0413] <Preparation of Comparative Light-Emitting Element 7> The comparative light-emitting element 7 was fabricated in the same manner as the comparative light-emitting element 1 described above, except for the electron transport layer 118 and the electron injection layer. The only difference was the process of forming the layer 130, and the other processes were the same as those of the comparative light-emitting element 1. Ta.

[0414] On the light-emitting layer 140, 2mDBTBPDBq-II was deposited to a thickness of 1.0 μm on the electron transport layer 118(1). Then, NBPhen was evaporated to a thickness of 20 nm as the electron transport layer 118(2). Next, an electron injection layer 130 was deposited on the electron transport layer 118(2). Li2O was evaporated to a thickness of 0.2 nm.

[0415] <Fabrication of Light-Emitting Elements 8 to 10> The light-emitting elements 8 to 10 were fabricated in the same manner as the comparative light-emitting element 7 described above, except that the electron transport layer 118 (2) and the process for forming the electron injection layer 130 are different. The other processes are the same as those of the comparative light-emitting element 7. The same manufacturing method was used.

[0416] <Fabrication of Light-emitting Device 8> The electron transport layer 118(2) of the light-emitting element 8 was formed by disposing NBPhe on the electron transport layer 118(1). n was evaporated to a thickness of 15 nm.

[0417] On the electron transport layer 118(2), an electron injection layer 130 was formed by depositing NBPhen and Ag in a weight ratio of ( NBPhen:Ag) was co-evaporated at a ratio of 1:0.19 to a thickness of 5 nm.

[0418] <Fabrication of Light-emitting Device 9> The electron transport layer 118(2) of the light-emitting element 9 was formed by disposing NBPhe on the electron transport layer 118(1). NBP was then deposited to a thickness of 10 nm as the electron transport layer 118(3). The weight ratio of hen and Ag (NBPhen:Ag) is 1:0.19, and the thickness is 5 nm. The mixture was co-evaporated as shown below.

[0419] On the electron transport layer 118(3), an electron injection layer 130 is formed by depositing 2Py3Tzn and Ag by weight. The ratio (2Py3Tzn:Ag) was 1:0.35 and the thickness was 5 nm. .

[0420] <Fabrication of Light-Emitting Element 10> As the electron transport layer 118(2) of the light-emitting element 10, NBPh was deposited on the electron transport layer 118(1). en was evaporated to a thickness of 15 nm.

[0421] On the electron transport layer 118(2), an electron injection layer 130 was formed by depositing TmPPPyTz and Ag by weight. The ratio (TmPPPyTz:Ag) was 1:0.15 and the thickness was 5 nm. Ta.

[0422] <Characteristics of light-emitting element> Next, the device characteristics of the comparative light-emitting element 7 and the light-emitting elements 8 to 10 prepared above were measured. The measurement method was the same as in Example 1 described above.

[0423] FIG. 2 shows the current efficiency-luminance characteristics of the comparative light-emitting element 7 and the light-emitting elements 8 to 10. 7, current density-voltage characteristics are shown in Fig. 28, power efficiency-luminance characteristics are shown in Fig. 29, and external quantum efficiency- The luminance characteristics are shown in FIG. 30. Each light-emitting element was supplied with a current of 2.5 mA / cm 2 At a current density of FIG. 31 shows the electroluminescence spectrum when a current was applied.

[0424] Also, 1000cd / m 2 Comparative light-emitting element 7 and light-emitting element 8 to The device characteristics of 10 are shown in Table 10.

[0425] [Table 10]

[0426] As shown in FIG. 30 and Table 10, the comparative light-emitting element 7 and the light-emitting elements 8 to 10 are All of them showed high luminous efficiency with an external quantum efficiency of more than 25%. As shown in FIG. 1, the current efficiency and power efficiency were also high. Light-emitting devices 8 to 10 are comparatively light-emitting devices using Li2O, which is a material commonly used for the electron injection layer. The efficiency was as high as that of the comparative light-emitting device 7.

[0427] As shown in FIG. 28, the comparative light-emitting element 7 and the light-emitting elements 8 to 10 have good electrical conductivity. The current density-voltage characteristics are shown. is equivalent to that of comparative light-emitting element 7, which uses Li2O, a material commonly used for the electron injection layer. It was found that the compound had an electron injection property of 100%.

[0428] 31, the comparative light-emitting element 7 and the light-emitting elements 8 to 10 are The peak wavelength of the emission spectrum is around 616 nm, and the full width at half maximum is 53 The obtained electroluminescence spectrum showed that the guest material It can be seen that the emission is from Ir(dmdppr-dmp)2(dpm).

[0429] Next, a driving life test was performed on the comparative light-emitting element 7 and the light-emitting elements 8 to 10. The measurement results of the life test are shown in FIG. 44. The driving life test was performed by setting the current density of each light-emitting element to 2 5mA / cm 2 The current density was set to 0.5 V, and each light-emitting element was continuously driven under a constant current density condition.

[0430] As shown in FIG. 44, the light-emitting elements 8 to 10 have driving lives equivalent to that of the comparative light-emitting element 7. Showed life.

[0431] For the above reasons, an organic compound having a triazine ring is also suitable for the light-emitting element of one embodiment of the present invention. It has been found that the configuration shown in this embodiment can be used in other embodiments and It can be used in appropriate combination with the embodiment. EXAMPLES

[0432] In this example, light-emitting elements 12 to 14, which are light-emitting elements of one embodiment of the present invention, and A fabrication example of a comparative light-emitting element 11 for comparison is shown below. The diagram is shown in FIG. 12, and the details of the element structure are shown in Table 11. The structures of the compounds used are The structures and abbreviations of other compounds are shown below. Just take into consideration the form.

[0433] [ka]

[0434] [Table 11]

[0435] In addition, the LUMO of HATNA used in the electron injection layer 130 of the light-emitting element 13 and the light-emitting element 14 The level was calculated by cyclic voltammetry (CV) measurement. The measurement method was the same as in Example 1. was carried out in a similar manner.

[0436] As a result, the LUMO of HATNA was calculated to be -3.50 eV.

[0437] <Preparation of Comparative Light-Emitting Element 11> The comparative light-emitting element 11 was fabricated in the same manner as the comparative light-emitting element 1 described above, except that the electron transport layer 118 and the electron injection layer The only difference is the process of forming the insulating layer 130, and the other processes are the same as those of the comparative light-emitting element 1. did.

[0438] The comparative light-emitting element 11 had an electron transport layer 118(1) formed of 2mDBTBPDBq-II. The deposition was carried out so as to give a thickness of 20 nm.

[0439] Next, NBPhen was deposited to a thickness of 118(1) as the electron transport layer 118(2). The comparative light-emitting element 11 had a thickness of 15 nm on the electron transport layer 118(2). In this case, the electron injection layer 130 was not provided.

[0440] <Fabrication of light-emitting element 12> The light-emitting element 12 was fabricated in the same manner as the comparative light-emitting element 11 described above, except for the steps of forming the electron injection layer 130. The fabrication method was the same as that for the comparative light-emitting element 11 except for the above steps.

[0441] As the electron injection layer 130 of the light emitting element 12, NBPhen and Ag was added to the mixture in a weight ratio (NBPhen:Ag) of 1:0.19 and a thickness of 5 nm. It was evaporated.

[0442] <Fabrication of Light-Emitting Element 13> The light-emitting element 13 was fabricated in the same manner as the comparative light-emitting element 11 described above, except that the electron transport layer 118(2) and the The only difference is the process of forming the electron injection layer 130, and the other processes are the same as those of the comparative light-emitting element 11. The method was as follows.

[0443] As the electron transport layer 118(2) of the light emitting element 13, NBPh was deposited on the electron transport layer 118(1). en was evaporated to a thickness of 10 nm.

[0444] On the electron transport layer 118(2), an electron injection layer 130 was formed by depositing NBPhen and Ag in a weight ratio of ( NBPhen:Ag) was co-deposited at 1:0.19 to a thickness of 5 nm. The weight ratio of HATNA and Ag (HATNA:Ag) was 1:0.28, and the thickness was 5 nm. The mixture was co-evaporated so that

[0445] <Fabrication of light-emitting element 14> The light emitting device 14 is a light emitting device in which a buffer layer 117 is further formed on the light emitting device 13 shown above. The other steps were the same as those for the light-emitting element 13.

[0446] On the electron injection layer 130, HAT-CN was evaporated to a thickness of 5 nm as the buffer layer 117.

[0447] <Characteristics of light-emitting element> Next, the element characteristics of the comparative light-emitting element 11 and the light-emitting elements 12 to 14 prepared above were evaluated. The measurement method was the same as in Example 1 described above.

[0448] The current efficiency-luminance characteristics of the fabricated comparative light-emitting element 11 and the light-emitting elements 12 to 14 were Fig. 32 shows the current-voltage characteristics, Fig. 33 shows the power efficiency-luminance characteristics, and Fig. 34 shows the external quantum efficiency- The luminance characteristics are shown in FIG. 35. Each light-emitting element was supplied with a current of 2.5 mA / cm 2 At a current density of FIG. 36 shows the electroluminescence spectrum when a current was applied.

[0449] Also, 1000cd / m 2 The comparative light-emitting element 11, the light-emitting element 12, and the light-emitting element The device characteristics of element 14 are shown in Table 12.

[0450] [Table 12]

[0451] As shown in FIG. 35 and Table 12, the light-emitting elements 12 to 14 all exhibited an external quantum efficiency of 1.0 μm. As shown in Fig. 32 and Fig. 34, the current efficiency and the On the other hand, the comparative light-emitting element 11, which does not have the electron injection layer 130, exhibited a low power efficiency. This is because the inclusion of the electron-injection layer of one embodiment of the present invention increases the emission efficiency of the light-emitting element. It is shown that the carrier balance is good. Since the efficiency of the light-emitting device 14 was similar to that of the light-emitting device 12, it is considered that HATNA has an unshared electron pair. It was found that the organic compound can be suitably used as a cathode and an electron injection layer. The light-emitting element 14 in which a buffer layer was laminated between the light-emitting element 12 and the light-emitting element 14 also exhibited characteristics similar to those of the light-emitting element 12.

[0452] In addition, as shown in FIG. 33, the light-emitting elements 12 to 14 exhibit excellent current-voltage characteristics. In addition, the current-voltage characteristics of both are equivalent, so it is possible to distinguish between HATNA and transition metals. The composite material was found to have good properties as an electron injection layer. The light-emitting device 14 in which a buffer layer was laminated between the interlayers also exhibited characteristics similar to those of the light-emitting device 12. On the other hand, the comparative light-emitting element 11, which does not have the electron injection layer 130, has a high driving voltage. By including the electron-injection layer of one embodiment of the present invention, the electron-injection property of the light-emitting element is improved. This shows that.

[0453] As shown in FIG. 36, the comparative light-emitting element 11, the light-emitting element 12, the light-emitting element 13, and the light-emitting element The peak wavelength of the electroluminescence spectrum of each of the 14 is around 618 nm, and the full width at half maximum is Both of them emitted red light at 58 nm. It was found that the emission was from the photoluminescence material Ir(dmdppr-dmp)2(dpm). Ta.

[0454] As described above, in the light-emitting element of one embodiment of the present invention, a compound having a plurality of ring structures such as HATNA can be used. Therefore, an organic compound having conjugated double bonds in the order of NCCN can be preferably used. In addition, it was found that the organic light-emitting element having an unshared electron pair, which is one embodiment of the present invention, A light emitting device with a buffer layer laminated between an electron injection layer made of a composite material of a compound and a transition metal and a cathode. The present invention also provides a light-emitting element with high light-emitting efficiency, reduced driving voltage, and low power consumption. It is possible.

[0455] <Evaluation of Reliability of Light-Emitting Device> Next, the comparative light-emitting element 11 and the light-emitting elements 12 to 14 were subjected to an operation life test. The measurement results of the driving life test are shown in FIG. 45. The driving life test was performed by changing the current density of each light-emitting element. 25mA / cm 2 The current density was set to 0.5 V, and each light-emitting element was continuously driven under a constant current density condition.

[0456] As shown in FIG. 45, the light-emitting elements 12 to 14 have better driving characteristics than the comparative light-emitting element 11. Furthermore, the light-emitting elements 13 and 14 exhibited better dynamic life than the light-emitting element 12. From this, it can be seen that the light-emitting element having the electron-injection layer according to one embodiment of the present invention has a high reliability. It was shown that the light emitting device was excellent.

[0457] Next, a constant temperature and humidity storage test was carried out on the light-emitting elements 13 and 14. Since no insulation was performed, the cathode and EL layer were exposed to the atmosphere of the test environment. be.

[0458] The light emitting element 13 and the light emitting element 14 were kept constant at a temperature of 65° C. and a humidity of 95%, respectively. After leaving them in the thermostatic chamber for 48 hours, the light emission state of each light emitting element was examined. The same as in Example 1. Table 13 shows the evaluation results.

[0459] [Table 13]

[0460] The ratio of the light-emitting area before and after the constant temperature and humidity storage test was estimated. The light-emitting area ratios of 14 and 15 were 83% and 67%, respectively. The light-emitting device was shown to have excellent moisture resistance.

[0461] The configuration shown in this embodiment may be used in appropriate combination with other embodiments and modes. can be done. EXAMPLES

[0462] In this example, light-emitting elements 16 to 18, which are light-emitting elements according to one embodiment of the present invention, and A comparative example of the fabrication of the comparative light-emitting element 15 is shown below. The schematic diagram is shown in FIG. 37, and the details of the element structure are shown in Table 14. The element structure shown in this example is a cathode. The EL layer is placed on the anode, which is called reverse stacking (the structure where the EL layer is placed on the anode is called forward stacking). The structures and abbreviations of the organic compounds used in this embodiment are the same as those in the previous embodiment. Please refer to embodiment 1 for further details.

[0463] [Table 14]

[0464] <Preparation of Comparative Light-Emitting Element 15> An ITSO film was formed as an electrode 101 on a substrate 210 to a thickness of 70 nm. The electrode area of ​​the electrode 101 is 4 mm 2 (2mm x 2mm).

[0465] Next, as the electron injection layer 130, NBPhen was deposited on the electrode 101 to a thickness of 5 nm. Then, Li2O was evaporated to a thickness of 0.2 nm.

[0466] Next, NBPhen was evaporated to a thickness of 30 nm on the electron injection layer 130 as the electron transport layer 118(1). Subsequently, 2mDBTBPDBq-II was deposited to a thickness of 3 μm for the electron transport layer 118(2). The deposition was carried out so that the thickness was 0 nm.

[0467] Next, 2mDBTBPDBq-II was added as the light-emitting layer 140 on the electron transport layer 118(2). , PCBBiF, Ir(dmdppr-dmp)2(dpm), and BTBPDBq-II:PCBBiF:Ir(dmdppr-dmp)2(dpm)) The mixture was co-evaporated to a thickness of 40 nm in a ratio of 0.75:0.25:0.06. In the light-emitting layer 140, 2mDBTBPDBq-II and PCBBiF were The guest material is Ir(dmdppr-dmp)2(dpm), and the guest material is a phosphorescent compound. ).

[0468] Next, as the hole transport layer 112 on the light emitting layer 140, BPAFLP was deposited to a thickness of 20 nm. It was evaporated like this.

[0469] Next, a hole injection layer 111 was formed on the hole transport layer 112 by depositing DBT3P-II and MoO3. The weight ratio (DBT3P-II:MoO3) was 1:0.5 and the thickness was 25 The deposition was carried out by co-evaporation so as to give a thickness of 1 nm.

[0470] Next, on the hole injection layer 111, aluminum (Al) was deposited to a thickness of 20 The deposition was carried out so as to obtain a thickness of 0 nm.

[0471] Next, without sealing, the device was heat-treated in air at 80°C for 1 hour. Element 13 was obtained.

[0472] <Fabrication of Light-Emitting Elements 16 to 18> Light-emitting elements 16 to 18 were fabricated by the same method as the comparative light-emitting element 15 described above, except that the electron injection layer 1 The only difference is the process of forming the electron transport layer 118(1) and the comparative light-emitting device. The preparation method was the same as that of 15.

[0473] <Fabrication of Light-Emitting Element 16> On the electrode 101, NBPhen and Ag were deposited in a weight ratio to form the electron injection layer 130 of the light emitting element 16. The layers were co-evaporated at a ratio of (NBPhen:Ag) of 1:0.19 to a thickness of 5 nm.

[0474] On the electron injection layer 130, NBPhen was evaporated to a thickness of 30 nm as the electron transport layer 118(1). .

[0475] <Fabrication of Light-Emitting Element 17> On the electrode 101, 2Py3Tzn and Ag were deposited by weight as the electron injection layer 130 of the light emitting element 17. The ratio (2Py3Tzn:Ag) was 1:0.35 and the thickness was 5 nm. Next, NBPhen and Ag were mixed in a weight ratio (NBPhen:Ag) of 1:0.19, and The film was co-evaporated to a thickness of 5 nm.

[0476] On the electron injection layer 130, NBPhen was evaporated to a thickness of 25 nm as the electron transport layer 118(1). .

[0477] <Fabrication of Light-Emitting Element 18> On the electrode 101, TmPPPyTz and Ag are laminated as the electron injection layer 130 of the light emitting element 18. Co-evaporation was performed with a ratio of TmPPyTz:Ag of 1:0.15 and a thickness of 5 nm. Next, NBPhen and Ag were mixed in a weight ratio (NBPhen:Ag) of 1:0.19. The deposition was carried out to a thickness of 5 nm.

[0478] On the electron injection layer 130, NBPhen was evaporated to a thickness of 25 nm as the electron transport layer 118(1). .

[0479] <Characteristics of light-emitting element> Next, the element characteristics of the comparative light-emitting element 15 and the light-emitting elements 16 to 18 fabricated above were evaluated. The measurement method was the same as in Example 1 described above.

[0480] The current efficiency-luminance characteristics of the fabricated comparative light-emitting element 15 and the light-emitting elements 16 to 18 were Fig. 38 shows the current density-voltage characteristics, Fig. 39 shows the power efficiency-luminance characteristics, and Fig. 40 shows the external quantum efficiency The efficiency-luminance characteristics are shown in FIG. 2 Current density FIG. 42 shows the electroluminescence spectrum when a current was passed through the material at 35° C.

[0481] Also, 1000cd / m 2 The comparative light-emitting element 15 and the light-emitting element 16 are in the vicinity of the The device characteristics of device 18 are shown in Table 15.

[0482] [Table 15]

[0483] As shown in FIG. 41 and Table 15, the comparative light-emitting element 15 and the light-emitting elements 16 to 18 Both of the devices exhibited extremely high external quantum efficiency exceeding 25%. As shown in FIG. 1, the current efficiency and power efficiency were also high. Since the efficiency of the light-emitting element 18 was similar to that of the comparative light-emitting element 15, it is considered that the light-emitting element 18 is an embodiment of the present invention. It was found that good luminous efficiency could be obtained by applying the element to an inverse stack element.

[0484] As shown in FIG. 39, the comparative light-emitting element 15 and the light-emitting elements 16 to 18 are excellent. The current density-voltage characteristics were also similar. Therefore, when the light-emitting element according to one embodiment of the present invention is used as an inverted stack element, a good current density-voltage characteristics were found to be obtained.

[0485] As shown in FIG. 42, the comparative light-emitting element 15 and the light-emitting elements 16 to 18 are The peak wavelengths of the electroluminescence spectra are all around 619 nm, and the full width at half maximum is The obtained electroluminescence spectrum showed that the guest material It can be seen that the emission is from Ir(dmdppr-dmp)2(dpm).

[0486] As described above, the light-emitting element which is one embodiment of the present invention can also be used as an inverted stack element. The configuration shown in the embodiment can be used in appropriate combination with other embodiments and modes. EXAMPLES

[0487] In this example, a manufacturing example of a light-emitting element 19 that is a light-emitting element of one embodiment of the present invention will be described. The cross-sectional schematic diagram of the light-emitting device fabricated in this example is the same as that in Figure 12. The details of the device structure are shown in Table 16. For the structures and abbreviations of the organic compounds used in this embodiment, please refer to the first embodiment. Just pour some drinks.

[0488] [Table 16]

[0489] <Fabrication of Light-emitting Device 19> A method for manufacturing the light-emitting element manufactured in this embodiment will be described below.

[0490] An electrode 101 made of an alloy of silver, palladium and copper (Ag-Pd-Cu, A 100 nm thick SiOx film was then formed on the SiOx substrate, followed by a 100 nm thick ITSO film. The electrode 101 had an area of ​​4 mm 2 (2mm x 2m m).

[0491] Next, a hole injection layer 111 made of DBT3P-II and molybdenum oxide ( MoO3) in a weight ratio (DBT3P-II:MoO3) of 1:0.5, The layers were co-evaporated to a thickness of 65 nm.

[0492] Next, as the hole transport layer 112 on the hole injection layer 111, BPAFLP was deposited to a thickness of 20 nm. The deposition was carried out as follows.

[0493] Next, on the hole transport layer 112, 2mDBTBPDBq-II and P CBBiF and Ir(dmdppr-dmp)2(dpm) in a weight ratio of (2mDBTBP DBq-II:PCBBiF:Ir(dmdppr-dmp)2(dpm)) is 0.75 The mixture was co-deposited in an amount of 0.25:0.06 and in a thickness of 40 nm. In the light-emitting layer 140, 2mDBTBPDBq-II and PCBBiF are host materials. and Ir(dmdppr-dmp)2(dpm) is the guest material (phosphorescent compound). .

[0494] Next, 2mDBTBPDBq-II was added as the electron transport layer 118(1) on the light-emitting layer 140. was evaporated to a thickness of 25 nm.

[0495] Next, NBPhen was deposited to a thickness of 118(1) as the electron transport layer 118(2). The deposition was carried out so that the thickness became 15 nm.

[0496] Next, NBPhen and Ag were laminated on the electron transport layer 118(2) as the electron injection layer 130. The deposition was carried out at a ratio (NBPhen:Ag) of 1:0.19 and a thickness of 5 nm. .

[0497] Next, on the electron injection layer 130, Ag was deposited to a thickness of 25 nm as the electrode 102. Then, DBT3P-II was evaporated to a thickness of 70 nm.

[0498] Next, without sealing, the device was heat-treated in air at 80°C for 1 hour. I had 19 children.

[0499] <Characteristics of light-emitting element> Next, the device characteristics of the light-emitting device 19 thus fabricated were measured. The measurement method was the same as that of the embodiment described above. Same as 1.

[0500] The current efficiency-luminance characteristics of the fabricated light-emitting device 19 are shown in FIG. 46, and the current-voltage characteristics are shown in FIG. The light emitting element 19 is also supplied with 2.5 mA / cm 2 The electric field when a current is passed with a current density of The emission spectrum is shown in Figure 48. The measurement was carried out at room temperature.

[0501] Also, 1000cd / m 2 Table 17 shows the element characteristics of the light-emitting element 19 in the vicinity.

[0502] [Table 17]

[0503] As shown in FIG. 48, the peak wavelength of the electroluminescence spectrum of the light-emitting element 19 is 616 nm. The resulting electroluminescence spectrum showed red light emission with a full width at half maximum of 24 nm. The emission is from the guest material Ir(dmdppr-dmp)2(dpm). I understand.

[0504] In addition, as shown in FIG. 46 and Table 17, the light-emitting element 19 emits deep red light, but The current efficiency exceeded 96 cd / A, demonstrating excellent efficiency.

[0505] In addition, as shown in FIG. 47, the light-emitting element 19 exhibited good current-voltage characteristics. It was found that the composite material of BPhen and Ag has good electron injection properties. Therefore, the metal used in the electron injection layer 130 and the metal used in the cathode electrode 102 are the same. Light emitting devices having metals have been shown to have good properties.

[0506] The configuration shown in this embodiment can be used in appropriate combination with other embodiments and mode of implementation. . EXAMPLES

[0507] In this embodiment, a passive 326 ppi monitor was used to evaluate crosstalk. The panel has RGB pixels arranged in stripes, with a pixel size of 78 μm. The subpixel (each RGB pixel) is 26μm×78μm, and the aperture ratio is 65.7 %.

[0508] Light-emitting element 20, which is a light-emitting element of one embodiment of the present invention, and comparative light-emitting element 21, which is a comparison thereof. A fabrication example is shown. A schematic cross-sectional view of the light-emitting device fabricated in this example is shown in FIG. The results are shown in Tables 18 and 19. In FIG. 51, the area 2622R is a red pixel, and the area 2622G is a The region 2622B represents a green pixel, and the region 2622C represents a blue pixel. The pixel has three colors: red (R), green (G), and blue (B). The light-emitting device fabricated in this example has multiple pixels arranged in the order of R pixels, G pixels, and B pixels. The structures and abbreviations of the compounds used are shown below. For the structures and abbreviations of other compounds, For details, the above examples and embodiments should be referred to.

[0509] [ka]

[0510] [Table 18]

[0511] [Table 19]

[0512] <Fabrication of light-emitting element> A method for manufacturing the light-emitting element manufactured in this embodiment will be described below. The light-emitting element 20 is an embodiment of the present invention. The electron injection layer between the two light-emitting units is an organic compound having an unshared electron pair. The comparative light-emitting element 21 is a light-emitting element using a mixed film of a compound and a transition metal. This is a light-emitting element that uses lithium oxide (Li2O), a commonly used Li compound.

[0513] <Fabrication of light-emitting element 20> On the substrate 2650, an electrode 2661, an electrode 2663, and an electrode 2664 are formed of aluminum ( The Al)-nickel (Ni)-lanthanum (La) alloy film was formed to a thickness of 200 nm. Next, a titanium (Ti) film was formed to a thickness of 6 nm, and then heated at 300°C for 1 hour. Then, the ITSO film was formed so that the R pixel was 80 nm thick and the G pixel was 40 nm thick. did.

[0514] Next, a hole injection layer 2631 is formed on the electrodes 2661, 2663, and 2664. T3P-II and molybdenum oxide (MoO3) were mixed in a weight ratio of (DBT3P-II:MoO 3) were co-deposited in an amount of 1:0.5 to a thickness of 13 nm.

[0515] Next, a hole transport layer 2632 was formed on the hole injection layer 2631 using PCPPn to a thickness of 20 nm. The vapor deposition was carried out so that

[0516] Next, on the hole transport layer 2632, a light emitting layer 2644 was formed by adding cgDBCzPA and 1.6 mM emFLPAPrn is mixed with cgDBCzPA:1,6mMemFLPAPrn at a weight ratio of 1 The light-emitting layer 2 was co-deposited so that the thickness of the light-emitting layer 2 was 30 nm. In 644, cgDBCzPA is the host material and 1,6mMemFLPAPrn is the guest material (fluorescent compound).

[0517] Next, cgDBCzPA was deposited to a thickness of 100 μm on the light-emitting layer 2644 as the electron transport layer 2633(1). The deposition was carried out so that the thickness became 5 nm.

[0518] Next, NBPhen was deposited on the electron transport layer 2633(1) as the electron transport layer 2633(2). The deposition was carried out to a thickness of 10 nm.

[0519] On the electron transport layer 2633(2), an electron injection layer 2634 was formed by depositing NBPhen and Ag by weight. The layers were co-evaporated to a ratio (NBPhen:Ag) of 1:0.19 and a thickness of 5 nm.

[0520] Next, a charge generation layer 2635 was formed on the electron injection layer 2634 using DBT3P-II and MoO 3. The weight ratio (DBT3P-II:MoO3) is 1:0.5, and the thickness is The film was co-evaporated to a thickness of 13 nm.

[0521] Next, a hole transport layer 2637 made of BPAFLP was formed on the charge generating layer 2635 to a thickness of 20 nm. The deposition was carried out so that the thickness became m.

[0522] Next, 2mDBTBPDBq-II and , PCBBiF and Ir(tBuppm)2(acac) in a weight ratio of (2mDBTBPD Bq-II:PCBBiF:Ir(tBuppm)2(acac)) is 0.7:0.3: The mixture was co-evaporated so that the concentration of the ZnO in the SiO2 layer was 0.06 and the thickness of the SiO2 layer was 20 nm. TBPDBq-II, PCBBiF, and Ir(dmdppr-dmp)2(dpm), Weight ratio (2mDBTBPDBq-II:PCBBiF:Ir(dmdppr-dmp) 2(dpm)) to be 0.8:0.2:0.06 and the thickness to be 20 nm. In the light-emitting layer 2646, 2mDBTBPDBq-II and PC BBiF is the host material, and Ir(dmdppr-dmp)2(dpm) and Ir(t Buppm)2(acac) is the guest material (phosphorescent compound).

[0523] Next, 2mDBTBPDBq- II was evaporated to a thickness of 15 nm.

[0524] Next, NBPhen was deposited on the electron transport layer 2638(1) as the electron transport layer 2638(2). The deposition was carried out to a thickness of 15 nm.

[0525] An electron injection layer 2639 is formed on the electron transport layer 2638(2) by depositing Li2O to a thickness of 0.2 nm. The deposition was carried out so that the thickness became m.

[0526] Next, on the electron injection layer 2639, an electrode 2662 made of Ag was formed to a thickness of 20 nm. Then, DBT3P-II was evaporated to a thickness of 70 nm.

[0527] Next, the device is sealed using an organic EL sealant in a nitrogen atmosphere glove box. The substrate 2652 for forming the light-emitting element is fixed to the substrate 2650 on which the organic compound is formed. Specifically, a sealant was applied to the periphery of the substrate 2652, and the substrate 265 was sealed. 2 and the substrate 2650 on which the organic compound is formed are bonded together, and ultraviolet light with a wavelength of 365 nm is irradiated. J / cm 2 The light-emitting element 20 was obtained by the above steps. .

[0528] <Preparation of Comparative Light-Emitting Element 21> The comparative light-emitting element 21 was fabricated in the same manner as the light-emitting element 20 described above, except that the electron transport layer 2633(2) and The only difference is the process of forming the electron injection layer 2634, and the other processes are the same as those of the light-emitting element 20. The method was as follows.

[0529] The electron transport layer 2633(2) of the comparative light-emitting element 21 was made of NBPhen having a thickness of 15 nm. Next, Li2O was deposited to a thickness of 0.2 nm as the electron injection layer 2634. Then, CuPc was evaporated to a thickness of 1 nm.

[0530] <Observation of crosstalk of each light-emitting element> The state of crosstalk in the light-emitting element 20 and the comparative light-emitting element 21 was evaluated. The results are shown in Fig. 52. Fig. 52(A) shows an image when the blue pixel of the light-emitting element 20 is caused to emit light. FIG. 52(B) is an enlarged photograph of the comparative light-emitting element 21 when the blue pixel is illuminated. The left side of the blue pixel indicated by the arrow in Figure 52(A) and (B) is an enlarged photograph of the pixel at the time of the observation. The blue pixels on the side (including the pixels indicated by the arrows) are receiving current, but the red pixels, green pixels, No current flows to the pixels to the right of the blue pixel indicated by the arrow.

[0531] 52(A) and 52(B), the comparative light-emitting element 21 is a green pixel adjacent to a blue pixel through which a current is passed. On the other hand, in comparison with the comparative light-emitting element 21, the light-emitting element It can be seen that in 20, the emission of the adjacent green and red pixels is suppressed. The element 21 uses Li2O, an alkali metal compound, in the electron transport layer adjacent to the charge generating layer. Therefore, Li is easily diffused in the electron transport layer, and the current flowing to the blue pixel that emits light is Crosstalk occurs because the electrons flow through the electron transport layer to the adjacent green and red pixels. On the other hand, the light-emitting element 20 according to one embodiment of the present invention uses a transition metal in the electron transport layer. Therefore, the metal is less likely to diffuse, and crosstalk can be suppressed.

[0532] Next, the emission intensity due to crosstalk of the pixels adjacent to the emitted blue pixel is The results are shown in Figure 53. The data shown in Figure 52 shows the brightness of red light emission extracted for red pixels from the data. The horizontal axis is the distance from the blue pixel indicated by the arrow in Figure 52 to the red pixel on the right side. The units of the vertical and horizontal axes are arbitrary. That is, the light-emitting element 20 has a lower emission intensity than the comparative light-emitting element 21. It was found that the distance over which crosstalk occurred was short.

[0533] From the above, it has been demonstrated that the light-emitting element according to one embodiment of the present invention is effective in suppressing crosstalk. It was. EXAMPLES

[0534] Light-emitting element 22, which is a light-emitting element of one embodiment of the present invention, and comparative light-emitting element 23, which is a comparison thereof. A fabrication example is shown in FIG. 54, which shows a schematic cross-sectional view of the light-emitting device fabricated in this example, and FIG. The structures and abbreviations of the organic compounds used in this example are shown in Table 20. For details, refer to the examples and the first embodiment.

[0535] <Fabrication of light-emitting element> The method for fabricating the light-emitting element in this embodiment is described below. The electron injection layer between the two light-emitting units is an organic compound having an unshared electron pair. The comparative light-emitting element 23 is a light-emitting element using a mixed film of a compound and a transition metal. This is a light-emitting device that uses Li2O, a commonly used Li compound.

[0536] [Table 20]

[0537] <Fabrication of light-emitting element 22> An ITSO film is formed as an electrode 3642 on a substrate 3650 to a thickness of 70 nm. The electrode area is 4 mm2 (2mm x 2mm).

[0538] Next, on the electrode 3642, DBT3P-II, MoO3, and The weight ratio (DBT3P-II:MoO3) was set to 1:0.5 and the thickness was set to 10 The mixture was co-evaporated to give a thickness of m.

[0539] Next, a hole transport layer 3632 was formed on the hole injection layer 3631 by depositing PCPPn to a thickness of 10 nm. The vapor deposition was carried out so that

[0540] Next, on the hole transport layer 3632, a light emitting layer 3644 was formed by dissolving cgDBCzPA and 1.6 mM emFLPAPrn is mixed with cgDBCzPA:1,6mMemFLPAPrn at a weight ratio of 1 The light-emitting layer 3 was co-deposited so that the thickness of the light-emitting layer 3 was 25 nm. In 644, cgDBCzPA is the host material and 1,6mMemFLPAPrn is the guest material (fluorescent compound).

[0541] Next, cgDBCzPA was deposited to a thickness on the light-emitting layer 3644 as the electron transport layer 3633(1). The deposition was carried out so that the thickness was 5 nm.

[0542] Next, NBPhen was deposited on the electron transport layer 3633(1) as the electron transport layer 3633(2). The deposition was carried out to a thickness of 10 nm.

[0543] On the electron transport layer 3633(2), an electron injection layer 3634 was formed by depositing NBPhen and Ag by weight. The layers were co-evaporated to a ratio (NBPhen:Ag) of 1:0.19 and a thickness of 5 nm.

[0544] Next, DBT3P-II and MoO were deposited on the electron injection layer 3634 as the charge generation layer 3635. 3. The weight ratio (DBT3P-II:MoO3) is 1:0.5, and the thickness is The film was co-evaporated to a thickness of 30 nm.

[0545] Next, a hole transport layer 3637 made of BPAFLP was formed on the charge generation layer 3635 to a thickness of 20 nm. The deposition was carried out so that the thickness became m.

[0546] Next, 2mDBTBPDBq-II and , PCBBiF and Ir(tBuppm)2(acac) in a weight ratio of (2mDBTBPD Bq-II:PCBBiF:Ir(tBuppm)2(acac)) is 0.7:0.3: The mixture was co-evaporated so that the concentration of the ZnO in the SiO2 layer was 0.06 and the thickness of the SiO2 layer was 20 nm. TBPDBq-II, PCBBiF, and Ir(dmdppr-dmp)2(dpm), Weight ratio (2mDBTBPDBq-II:PCBBiF:Ir(dmdppr-dmp) 2(dpm)) to be 0.8:0.2:0.06 and the thickness to be 20 nm. In the light-emitting layer 3646, 2mDBTBPDBq-II and PC BBiF is the host material, and Ir(dmdppr-dmp)2(dpm) and Ir(t Buppm)2(acac) is the guest material (phosphorescent compound).

[0547] Next, 2mDBTBPDBq- II was evaporated to a thickness of 15 nm.

[0548] Next, NBPhen was deposited on the electron transport layer 3638(1) as the electron transport layer 3638(2). The deposition was carried out to a thickness of 10 nm.

[0549] On the electron transport layer 3638(2), an electron injection layer 3639 was formed by depositing NBPhen and Ag by weight. The layers were co-evaporated to a ratio (NBPhen:Ag) of 1:0.19 and a thickness of 5 nm.

[0550] Next, on the electron injection layer 3639, an electrode 3641 is formed by depositing Al to a thickness of 200 nm. It was evaporated like this.

[0551] Next, the device is sealed using an organic EL sealant in a nitrogen atmosphere glove box. A substrate 3652 for forming the light-emitting element is fixed to the substrate 3650 on which the organic compound is formed. Specifically, a sealant was applied to the periphery of the substrate 3652, and the substrate 365 was sealed. 2 and a substrate 3650 on which an organic compound film is formed are bonded together, and ultraviolet light with a wavelength of 365 nm is applied. 6J / cm 2 The light-emitting element 22 was obtained by the above steps. Ta.

[0552] <Preparation of Comparative Light-Emitting Element 23> The comparative light-emitting element 23 was fabricated in the same manner as the light-emitting element 22 described above, except that the electron transport layer 3633(2) and the Only the steps of forming the electron injection layer 3634, the electron transport layer 3638(2), and the electron injection layer 3639 are performed. The other steps were the same as those for the light emitting element 22.

[0553] The electron transport layer 3633(2) of the comparative light-emitting element 23 was formed on the electron transport layer 3633(1). NBPhen was evaporated to a thickness of 15 nm.

[0554] On the electron transport layer 3633(2), an electron injection layer 3634 was formed by depositing Li2O to a thickness of 0.2 nm. Then, CuPc was evaporated to a thickness of 1 nm.

[0555] As the electron transport layer 3638(2), NBPhen was deposited on the electron transport layer 3638(1) to a thickness of 100 nm. The deposition was carried out so that the thickness became 15 nm.

[0556] An electron injection layer 3639 was formed on the electron transport layer 3638(2) with a thickness of 1 nm using LiF. The deposition was carried out so that

[0557] <Measurement of each light-emitting element> The device characteristics of the fabricated light-emitting element 22 and the comparative light-emitting element 23 were measured. Luminance and CI The E chromaticity was measured using a color luminance meter (Topcon, BM-5A) and the electroluminescence spectrum A multichannel spectrometer (PMA-11, manufactured by Hamamatsu Photonics KK) was used for the measurement.

[0558] FIG. 55 shows the current efficiency-luminance characteristics of the fabricated light-emitting element 22 and the comparative light-emitting element 23. The voltage characteristics are shown in Fig. 56, the power efficiency-luminance characteristics are shown in Fig. 57, and the external quantum efficiency-luminance characteristics are shown in Fig. The measurements of each light-emitting device were carried out at room temperature (an atmosphere maintained at 23°C). In addition, each light-emitting element is supplied with 2.5mA / cm 2 The electroluminescence spectrum when a current is applied at a current density of The torque is shown in Figure 59. The measurements were carried out at room temperature.

[0559] Also, 1000cd / m 2 The element characteristics of the light-emitting element 22 and the comparative light-emitting element 23 in the vicinity The properties are shown in Table 21.

[0560] [Table 21]

[0561] As shown in FIG. 58 and Table 21, both the light-emitting element 22 and the comparative light-emitting element 23 have an external As shown in Figures 55 and 57, the current efficiency was 30%. The light-emitting element 22 also exhibited high efficiency and power efficiency. The light-emitting element 23 and the comparative light-emitting element 24 showed comparable light-emitting efficiency. The device 22 is a comparative example using Li2O and LiF, which are materials commonly used for the electron injection layer. The efficiency was as high as that of the comparative light emitting device 23.

[0562] As shown in FIG. 56, the light-emitting element 22 and the comparative light-emitting element 23 have a good current density-voltage In addition, the mixed film of NBPhen and Ag has excellent electron injection properties. It was found that...

[0563] As shown in FIG. 59, the electroluminescence spectra of the light-emitting element 22 and the comparative light-emitting element 23 are The peak wavelengths of the light-emitting elements are around 467 nm, 538 nm, and 617 nm. The comparative light-emitting element 23 emits white light having peaks in the wavelength ranges of all three colors: blue, green, and red. In addition, the electroluminescence spectra of the light-emitting element 22 and the comparative light-emitting element 23 were Since the spectra are almost the same, the light-emitting element 22 according to one embodiment of the present invention has The device has excellent electron injection properties equivalent to those of the comparative light-emitting device 23 that uses a commonly used Li compound. I found out that.

[0564] As described above, the light-emitting element according to one embodiment of the present invention can be formed by using a Li Since it has excellent electron injection properties equivalent to those of light-emitting devices using compounds, it has low driving voltage and emits light. A highly efficient light emitting element can be provided. EXAMPLES

[0565] A manufacturing example of light-emitting elements 24 to 26, which are light-emitting elements according to one embodiment of the present invention, will be described. A schematic cross-sectional view of the light-emitting device fabricated in this example is shown in Figure 54, and details of the device structure are shown in Table 22. The structures and abbreviations of the compounds used in this example are the same as those in the previous examples and embodiment 1. Please take the following into consideration.

[0566] [Table 22]

[0567] <Fabrication of light-emitting element 24> An ITSO film is formed as an electrode 3642 on a substrate 3650 to a thickness of 70 nm. The electrode area is 4 mm 2 (2mm x 2mm).

[0568] Next, on the electrode 3642, DBT3P-II, MoO3, and The weight ratio (DBT3P-II:MoO3) was set to 1:0.5, and the thickness was set to 65 nm. The mixture was co-evaporated to give a thickness of m.

[0569] Next, a hole transport layer 3632 is formed on the hole injection layer 3631 by depositing BPAFLP to a thickness of 20 nm. The deposition was carried out so that the thickness became m.

[0570] Next, on the hole transport layer 3632, 2mDBTBPDBq-II and , PCBBiF and Ir(dmdppr-dmp)2(dpm) in a weight ratio of (2mDBT BPDBq-II:PCBBiF:Ir(dmdppr-dmp)2(dpm)) was 0. The layers were co-evaporated to a thickness of 40 nm in an amount of 75:0.25:0.06. In the light-emitting layer 3644, 2mDBTBPDBq-II and PCBBiF are hosts. material, and Ir(dmdppr-dmp)2(dpm) is the guest material (phosphorescent compound). It is.

[0571] Next, 2mDBTBPDBq- II was evaporated to a thickness of 10 nm.

[0572] Next, NBPhen was deposited on the electron transport layer 3633(1) as the electron transport layer 3633(2). The deposition was carried out to a thickness of 15 nm.

[0573] On the electron transport layer 3633(2), an electron injection layer 3634 was formed by depositing NBPhen and Ag by weight. The layers were co-evaporated to a ratio (NBPhen:Ag) of 1:0.19 and a thickness of 5 nm.

[0574] Next, DBT3P-II and MoO were deposited on the electron injection layer 3634 as the charge generation layer 3635. 3. The weight ratio (DBT3P-II:MoO3) is 1:0.5, and the thickness is The film was co-evaporated to a thickness of 80 nm.

[0575] Next, a hole transport layer 3637 made of BPAFLP was formed on the charge generation layer 3635 to a thickness of 20 nm. The deposition was carried out so that the thickness became m.

[0576] Next, 2mDBTBPDBq-II and , PCBBiF and Ir(dmdppr-dmp)2(dpm) in a weight ratio of (2mDBT BPDBq-II:PCBBiF:Ir(dmdppr-dmp)2(dpm)) was 0. The layers were co-evaporated to a thickness of 40 nm in an amount of 75:0.25:0.06. In the light-emitting layer 3646, 2mDBTBPDBq-II and PCBBiF are hosts. material, and Ir(dmdppr-dmp)2(dpm) is the guest material (phosphorescent compound). It is.

[0577] Next, 2mDBTBPDBq- II was evaporated to a thickness of 25 nm.

[0578] Next, NBPhen was deposited on the electron transport layer 3638(1) as the electron transport layer 3638(2). The deposition was carried out to a thickness of 15 nm.

[0579] An electron injection layer 3639 was formed on the electron transport layer 3638(2) using LiF with a thickness of 1 nm. The deposition was carried out so that

[0580] Next, on the electron injection layer 3639, an electrode 3641 is formed by depositing Al to a thickness of 200 nm. It was evaporated like this.

[0581] Next, the device is sealed using an organic EL sealant in a nitrogen atmosphere glove box. A substrate 3652 for forming the light-emitting element is fixed to the substrate 3650 on which the organic compound is formed. Specifically, a sealant was applied to the periphery of the substrate 3652, and the substrate 365 was sealed. 2 and a substrate 3650 on which an organic compound film is formed are bonded together, and ultraviolet light with a wavelength of 365 nm is applied. 6J / cm 2 The light-emitting element 24 was obtained by the above steps. Ta.

[0582] <Fabrication of Light-Emitting Device 25 and Light-Emitting Device 26> The light-emitting elements 25 and 26 were fabricated by the same method as the light-emitting element 24 described above, except that the electron injection layer 363 The only difference was the formation process of the light emitting element 4, and the other processes were the same as those for the light emitting element 24.

[0583] <Fabrication of Light-Emitting Element 25> The light-emitting element 25 has an electron transport layer 3633(2) and an electron injection layer 3634 formed of Alq3 and A g were co-deposited in a weight ratio (Alq3:Ag) of 1:0.24 to a thickness of 5 nm. .

[0584] <Preparation of Light-Emitting Element 26> On the electron transport layer 3633(2) of the light-emitting element 26, 2mDBTB was used as the electron injection layer 3634. The weight ratio of PDBq-II and Ag (2mDBTBPDBq-II:Ag) was 1:0.20 and The layers were co-evaporated to a thickness of 5 nm.

[0585] <Measurement of each light-emitting element> The device characteristics of the fabricated light-emitting elements 24 to 26 were measured. was carried out in a similar manner.

[0586] FIG. 60 shows the current efficiency vs. luminance characteristics of the fabricated light-emitting elements 24 to 26. The voltage characteristics are shown in Figure 61, the power efficiency vs. luminance characteristics in Figure 62, and the external quantum efficiency vs. luminance characteristics in Figure 63. The measurements of each light-emitting element were carried out at room temperature (an atmosphere maintained at 23°C). Each light-emitting element was supplied with 2.5mA / cm 2 Electroluminescence spectrum when a current is applied at a current density of The results are shown in Figure 64. The measurements were carried out at room temperature.

[0587] Also, 1000cd / m 2 The element characteristics of the light emitting elements 24 to 26 in the vicinity Shown in Table 23.

[0588] [Table 23]

[0589] As shown in FIG. 63 and Table 23, the light-emitting elements 24 to 26 all have an external quantum efficiency. As shown in Figures 60 and 62, the current efficiency and the luminous efficiency were high. The power efficiency was also high. In particular, the light-emitting elements 24 and 26 showed high efficiency. Therefore, the light-emitting element according to one embodiment of the present invention has high emission efficiency. can be done.

[0590] In addition, as shown in FIG. 61, the light-emitting elements 24 to 26 have excellent current density-voltage characteristics. In particular, the light-emitting elements 24 and 26 exhibited favorable current density-voltage characteristics. Therefore, composite materials of organic compounds with unshared electron pairs and transition metals have good electron injection properties. I found out that I have it.

[0591] As shown in FIG. 64, the electroluminescence spectra of the light-emitting elements 24 to 26 are The peak wavelengths are all around 619 nm, and the full width at half maximum is around 60 nm. The obtained electroluminescence spectrum showed that the guest material Ir(dmd It was found that the emission was from ppr-dmp)2 (dpm).

[0592] As described above, the light-emitting element of one embodiment of the present invention has excellent electron injection properties and therefore requires low driving voltage. The structure shown in this embodiment is different from other embodiments and embodiment modes. They can be used in appropriate combination. EXAMPLES

[0593] In this example, light-emitting elements 27 to 29 which are light-emitting elements of one embodiment of the present invention and 1 shows an example of fabricating a comparative light-emitting element 30 for comparison. The details of the device structure are shown in Figure 54 and Tables 24 and 25. The structures and abbreviations of the objects may be referred to in the above examples and embodiments.

[0594] [Table 24]

[0595] [Table 25]

[0596] <Fabrication of light-emitting element> The method for fabricating the light-emitting device according to this embodiment is described below. This is a light-emitting device that uses Li2O and LiF, which are Li compounds commonly used in the layer. The light-emitting elements 27 to 29 each have an unshared electron pair in an electron-injection layer, which is one embodiment of the present invention. The light-emitting element 27 is a light-emitting element using a mixed film of an organic compound having the above-mentioned characteristic and a transition metal. In the example of 29, an organic compound having a triazine ring is used as an organic compound having an unshared electron pair. The light emitting device used will be exemplified.

[0597] <Fabrication of Light-Emitting Element 27> The light-emitting element 27 was fabricated by the same process as the light-emitting element 24 described above, except that the electron transport layer 3638 and the electron injection layer 3 Only the process for forming 639 was different, and the other processes were the same as those for the light-emitting element 24.

[0598] On the electron transport layer 3638(1) of the light-emitting element 27, NBP was deposited as the electron transport layer 3638(2). Hen was evaporated to a thickness of 10 nm.

[0599] On the electron transport layer 3638(2), an electron injection layer 3639 was formed by depositing NBPhen and Ag by weight. The layers were co-evaporated to a ratio (NBPhen:Ag) of 1:0.19 and a thickness of 5 nm.

[0600] <Fabrication of Light-emitting Device 28 and Light-emitting Device 29> The light-emitting elements 28 and 29 were fabricated by the same method as the light-emitting element 27 described above, except that the electron transport layer 363 The only difference is the process of forming the electron injection layer 3634. The other processes are the same as those of the light-emitting element 2. The preparation method was the same as in 7.

[0601] <Fabrication of Light-Emitting Element 28> On the electron transport layer 3633(1) of the light-emitting element 28, NBP was deposited as the electron transport layer 3633(2). Hen was evaporated to a thickness of 10 nm.

[0602] On the electron transport layer 3633(2), an electron injection layer 3634 was formed by depositing NBPhen and Ag by weight. The deposition was carried out in such a way that the ratio (NBPhen:Ag) was 1:0.19 and the thickness was 5 nm. The weight ratio of 2Py3Tzn and Ag (2Py3Tzn:Ag) was 1:0.35 and the thickness was The deposition was carried out by co-evaporation so that the thickness became 5 nm.

[0603] <Fabrication of Light-Emitting Element 29> On the electron transport layer 3633(1) of the light-emitting element 29, NBP was deposited as the electron transport layer 3633(2). Hen was evaporated to a thickness of 10 nm.

[0604] On the electron transport layer 3633(2), an electron injection layer 3634 was formed by depositing NBPhen and Ag by weight. The deposition was carried out in such a way that the ratio (NBPhen:Ag) was 1:0.19 and the thickness was 5 nm. The weight ratio of TmPPPyTz and Ag (TmPPPyTz:Ag) was 1:0.15 and The film was co-evaporated to a thickness of 5 nm.

[0605] <Preparation of Comparative Light-Emitting Element 30> The comparative light-emitting element 30 was fabricated in the same manner as the light-emitting element 27 described above, except that the electron transport layer 3633(2) and the The only differences are the formation processes of the electron injection layer 3634, the electron transport layer 3638(2), and the electron injection layer 3639. The other steps were the same as those for the light-emitting element 27.

[0606] The electron transport layer 3633(2) was formed on the electron transport layer 3633(1) of the comparative light-emitting element 30. BPhen was evaporated to a thickness of 20 nm.

[0607] On the electron transport layer 3633(2), an electron injection layer 3634 was formed by depositing Li2O to a thickness of 0.2 nm. The deposition was carried out so that the thickness became m.

[0608] On the electron transport layer 3638(1), NBPhen was depo...

Claims

1. An anode; A cathode; a light-emitting layer between the anode and the cathode; a first layer that forms a SOMO between the light-emitting layer and the cathode; the first layer contains a compound having at least one of a diazine ring or a triazine ring, The light-emitting device, wherein the first layer has a thickness of 3 nm or more and 20 nm or less.

2. In claim 1, A light-emitting device, wherein the host material of the light-emitting layer contains a compound having at least one of a diazine ring or a triazine ring.

3. An anode; A cathode; a first light-emitting unit and a second light-emitting unit between the anode and the cathode; a first layer that forms a SOMO between the first light-emitting unit and the second light-emitting unit; the first layer contains a compound having at least one of a diazine ring or a triazine ring, The light-emitting device, wherein the first layer has a thickness of 3 nm or more and 20 nm or less.

4. In claim 3, A light-emitting element, wherein a host material of the light-emitting layer of the first light-emitting unit includes a compound having at least one of a diazine ring or a triazine ring.

5. In claim 1 or claim 3, The compound has a glass transition temperature of 100° C. or higher.

Images