Light-emitting device

Abstract

To provide a light-emitting element with high light extraction efficiency.SOLUTION: A light-emitting element includes a light-emitting layer between a pair of electrodes. Between the light-emitting layer and an anode or between the light-emitting layer and a cathode, a low light refractive index layer containing an organic compound and an inorganic compound is provided. The refractive index of the low light refractive index layer is 1.80 or less at the wavelength of light extracted from the light-emitting layer.SELECTED DRAWING: Figure 35

Description

[Technical Field]

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

[0002] It should be noted that one aspect of the present invention is not limited to the above-mentioned technical fields. The present invention relates to a process, a machine, a manufacture, or a manufacturing method. In particular, one aspect of the present invention relates to a composition of matter. The present invention relates to a semiconductor device, a light emitting device, a display device, a lighting device, a light emitting element, and a method for manufacturing these. [Background technology]

[0003] Electroluminescence (EL) using organic compounds The practical application of light-emitting elements (organic EL elements) that utilize the The basic structure is that a semiconductor layer containing an organic compound is sandwiched between a pair of electrodes.

[0004] Such light-emitting elements have various advantages, such as being lightweight, flexible, highly designable, and being able to be processed by coating. Because of the various advantages, research and development of light-emitting devices is actively progressing. Therefore, when used as display pixels, they have high visibility and do not require a backlight. These advantages make it suitable for use as a flat panel display element.

[0005] Such light-emitting devices are mainly made of organic compounds, and an organic semiconductor layer is formed therein. Since the organic compound and layer structure have a significant effect on the light-emitting element, Furthermore, for light-emitting devices, a structure with high light extraction efficiency is important. .

[0006] Various methods have been proposed to improve the light extraction efficiency of organic EL elements. The light extraction efficiency is improved by creating an uneven shape on parts of the electrodes and EL layer. In addition, in Patent Document 2, a low refractive index layer and a high refractive index layer are provided on the outside of the electrode, which improves the light extraction efficiency. It improves the rate.

[0007] One of the problems that often arises with organic EL devices is low light extraction efficiency. In particular, attenuation due to reflection caused by differences in refractive index is a major factor that reduces the efficiency of the device. To reduce this effect, a layer made of a low refractive index material is placed inside the EL layer. A configuration for forming the above has been proposed (see, for example, Non-Patent Document 1). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-33706 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-270225 [Non-Patent Document 1] J.-J. Kim, Adv, Mater. 28, 4920(2016) Summary of the Invention [Problem to be solved by the invention]

[0009] In the light-emitting element, as described above, a method for improving the light extraction efficiency is to However, there are many methods for providing a low refractive index layer on the substrate. Many of the materials have low carrier transport properties, and when a low refractive index layer is provided between a pair of electrodes, the light-emitting element In addition, when a low refractive index layer is provided on the outside of the electrode, However, there is a problem that the manufacturing process becomes complicated. Therefore, we have developed a method that can be manufactured easily and improves light extraction efficiency. There is a need to develop a layer structure that can achieve this.

[0010] In view of the above-described problems, an object of one embodiment of the present invention is to provide a light-emitting element with high light extraction efficiency. Another object of one embodiment of the present invention is to provide a light-emitting element including a low refractive index layer. Another object of one embodiment of the present invention is to provide a light-emitting element with low driving voltage. 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 highly reliable light-emitting element. Another object of one embodiment of the present invention is to provide a light-emitting element with high emission efficiency. Another object of one embodiment of the present invention is to provide a novel light-emitting element. An object of one embodiment of the present invention is to provide a novel electronic device. An object of the present invention is to provide a novel lighting device.

[0011] Note that the above description of the object does not preclude the existence of other objects. However, it is not necessary to solve all of these problems. Problems other than those mentioned above can be solved by the description of the specification, etc. It is obvious from the description of the specification that other problems can be extracted. . [Means for solving the problem]

[0012] One embodiment of the present invention is a light-emitting element having a first electrode, a second electrode, a light-emitting layer, and an organic layer. The light-emitting element has a first electrode and a second electrode between the light-emitting layer and the first layer, and the second electrode is The organic layer is provided between the first electrode and the organic layer, and the organic layer is provided in contact with the second electrode. The first electrode has a function of reflecting light, and the second electrode has a function of reflecting light and a function of transmitting light. The light emitting layer emits light with a peak wavelength λ, and the first layer emits light from the interface of the light emitting layer on the first electrode side. The optical distance from the light emitting layer to the second electrode side interface is within λ / 2, or the optical distance from the light emitting layer to the second electrode side interface is within λ / 2, and the refractive index of the first layer is 1.80 or less.

[0013] Another aspect of the present invention is a light-emitting device having a first electrode, a second electrode, a light-emitting layer, and an organic layer. The light-emitting element has a light-emitting layer and a first layer between a first electrode and a second electrode, The second electrode is provided between the first electrode and the organic layer, and the organic layer is provided in contact with the second electrode. The first electrode has a function of reflecting light, and the second electrode has a function of reflecting light and transmitting light. The first layer has a function of providing a first electric field to the light-emitting layer, and the light-emitting layer emits light having a peak wavelength λ. The optical distance from the electrode side interface is within λ / 2, or the light from the second electrode side interface of the light-emitting layer The first layer is provided in a region where the optical path length is within λ / 2, and the first layer has a first organic compound. The compound has a refractive index of 1.80 or less.

[0014] Another embodiment of the present invention is a light-emitting device including a first electrode, a second electrode, a third electrode, a light-emitting layer, and and an organic layer, and the light-emitting layer and the first electrode are disposed between the first electrode and the second electrode. The second electrode is provided between the first electrode and the organic layer, and the organic layer is connected to the second electrode. The first electrode and the third electrode are in contact with each other, and the first electrode has a function of reflecting light. The second electrode has a function of reflecting light and a function of transmitting light, and transmits light having a peak wavelength λ The first layer has an optical distance of λ / 2 or less from the interface of the light-emitting layer on the first electrode side. the light-emitting layer is provided in a region or a region whose optical distance from the interface on the second electrode side of the light-emitting layer is within λ / 2, A region from either the first electrode side interface or the second electrode side interface of the light-emitting layer to the third electrode. The optical path length is in the range of λ / 4±50 nm, and the first electrode side interface of the light-emitting layer or the second electrode The optical distance from either side interface to the first electrode is in the range of 3λ / 4±50 nm. The light-emitting device has a refractive index of the first layer of 1.80 or less.

[0015] Another embodiment of the present invention is a light-emitting device including a first electrode, a second electrode, a third electrode, a light-emitting layer, and and an organic layer, and the light-emitting layer and the first electrode are disposed between the first electrode and the second electrode. The second electrode is provided between the first electrode and the organic layer, and the organic layer is connected to the second electrode. The first electrode and the third electrode are in contact with each other, and the first electrode has a function of reflecting light. The second electrode has a function of reflecting light and a function of transmitting light, and transmits light having a peak wavelength λ The first layer has an optical distance of λ / 2 or less from the interface of the light-emitting layer on the first electrode side. the light-emitting layer is provided in a region or a region whose optical distance from the interface on the second electrode side of the light-emitting layer is within λ / 2, A region from either the first electrode side interface or the second electrode side interface of the light-emitting layer to the third electrode. The optical path length is in the range of λ / 4±50 nm, and the first electrode side interface of the light-emitting layer or the second electrode The optical distance from either side interface to the first electrode is in the range of 3λ / 4±50 nm. The first layer includes a first organic compound, and the refractive index of the first organic compound is 1.80 or less. It is a light-emitting element.

[0016] In the above structure, the first layer preferably has a thickness of 5 nm or more.

[0017] In the above configuration, it is preferable that the first electrode is an anode and the second electrode is a cathode. .

[0018] In the above structure, the refractive index of the first layer is preferably lower than the refractive index of the third electrode. stomach.

[0019] In the above structure, the third electrode preferably has optical transparency.

[0020] In the above structure, the first organic compound preferably has electron donating properties.

[0021] In the above structure, the refractive index of the first layer is preferably lower than the refractive index of the light-emitting layer.

[0022] Another embodiment of the present invention is a light-emitting device including an anode, a cathode, and an EL layer. The EL layer is located between the cathode and the organic compound. The EL layer contains an organic compound and an inorganic compound. It is a light-emitting element in which at least a part of the light-emitting element exists in a microcrystalline state.

[0023] Alternatively, another embodiment of the present invention is a light-emitting layer in the above structure, in which the EL layer has a light-emitting layer and the light-emitting layer is in a microcrystalline state. The inorganic compound present as a light-emitting element is present between the light-emitting layer and the cathode.

[0024] Alternatively, in the above structure, another embodiment of the present invention is a light-emitting diode (LED) device, wherein the EL layer includes an electron-transporting layer. The electron transport layer is located between the light emitting layer and the cathode, and is made of inorganic compounds that exist in a microcrystalline state. The light-emitting element is present in the layer.

[0025] Alternatively, another embodiment of the present invention is a compound having the above structure, wherein the compound is present in a microcrystalline state. A light emitting element is in contact with the cathode.

[0026] Alternatively, another embodiment of the present invention includes an anode, a cathode, and an EL layer. The EL layer has an emitting layer, and the EL layer has an organic compound between the emitting layer and the cathode. The light-emitting device has a low refractive index layer containing an inorganic compound and an inorganic compound.

[0027] Alternatively, in the above structure, another embodiment of the present invention is a method for manufacturing a semiconductor device, wherein the inorganic compound is an alkali metal fluoride. The light-emitting element is a fluoride of an alkaline earth metal or an alkaline earth metal.

[0028] Alternatively, in the above structure, another embodiment of the present invention is a method for manufacturing a semiconductor device, wherein the refractive index of the low refractive index layer is The wavelength of the extracted light is 1.70 or less.

[0029] Alternatively, another embodiment of the present invention is a light-emitting diode (LED) having the above structure, wherein the EL layer further includes an electron-transport layer, The electron transport layer is located between the light emitting layer and the cathode, and at least a part of the low refractive index layer is an electron transport layer. It is a light-emitting element that plays the role of a layer.

[0030] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the low refractive index layer is an electron transport layer. It is an element.

[0031] Alternatively, in the above structure, another embodiment of the present invention is a structure in which the EL layer is provided between the light-emitting layer and the anode. The light-emitting element has a low refractive index layer.

[0032] Alternatively, in the above structure, another embodiment of the present invention is such that the EL layer has a layer between the light-emitting layer and the anode, The low refractive index layer includes a first material, a second material, and a third material, and the first material is fluorine. the second substance is an organic compound having a hole transporting property, and the third substance is The second substance is a light-emitting element that exhibits electron accepting properties.

[0033] Alternatively, in the above structure, another embodiment of the present invention is a semiconductor device in which the first substance is a fluoride of an alkali metal. The light-emitting element is a fluoride of an alkaline earth metal or an alkyl fluoride.

[0034] Alternatively, another embodiment of the present invention is a semiconductor device having the above structure, wherein the first substance is an alkaline earth metal. It is a light-emitting element that is a fluoride.

[0035] Alternatively, in the above structure, another embodiment of the present invention is a semiconductor device in which the first substance is lithium fluoride, fluorine, or the like. The light-emitting element is either calcium fluoride or magnesium fluoride.

[0036] Alternatively, in the above structure, another embodiment of the present invention is a semiconductor device in which the third substance is a transition metal oxide, an elemental Oxides of metals belonging to groups 4 to 8 of the periodic table and organic compounds with electron-withdrawing groups The light-emitting device is one or more of the compounds.

[0037] Alternatively, in the above structure, another embodiment of the present invention is a semiconductor device in which the third substance is titanium oxide, vanadium oxide, or the like. tungsten oxide, rhenium oxide, tantalum oxide, molybdenum oxide, tungsten oxide, rhenium oxide , ruthenium oxide, chromium oxide, zirconium oxide, hafnium oxide, silver oxide , 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane, chloro Ranyl, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexyl Triphenylene, 1,3,4,5,7,8-hexafluorotetracyano-naphtho Quinodimethane, α,α',α''-1,2,3-cyclopropanetriylidenetris[4 -cyano-2,3,5,6-tetrafluorobenzeneacetonitrile] Alternatively, the light emitting element may be of a plurality of types.

[0038] Alternatively, in the above structure, another embodiment of the present invention is a semiconductor device in which the third substance is molybdenum oxide. It is a light-emitting element.

[0039] Alternatively, another embodiment of the present invention may be a compound having the above structure, wherein the second substance is a π-electron-rich heteroaromatic compound. The light-emitting element is an aromatic compound or an aromatic amine compound.

[0040] Alternatively, in another embodiment of the present invention, in the above structure, the HOMO level of the second substance is −5. The light-emitting element has a luminance of 7 eV or more.

[0041] Alternatively, in another embodiment of the present invention, in the above structure, the HOMO level of the second substance is −5. The light-emitting element has a luminance of 5 eV or more.

[0042] Alternatively, in another embodiment of the present invention, in the above structure, the refractive index of the low refractive index layer is 1.70 or less. It is a light-emitting element.

[0043] Alternatively, in the above structure, another embodiment of the present invention is a method for manufacturing a semiconductor device, comprising: forming a light-emitting layer between the light-emitting layer and the low-refractive-index layer; The light-emitting element has a hole transport layer, and the hole transport layer contains an organic compound having a hole transport property.

[0044] Alternatively, in the above structure, another embodiment of the present invention is a light-emitting diode (ELD) layer having a hole-injection layer in contact with an anode. the hole injection layer includes a first hole injection layer and a second hole injection layer, and the first hole injection layer The first hole injection layer is a low refractive index layer, and the second hole injection layer is a low refractive index layer. The hole injection layer includes a fourth substance and a fifth substance, and the fourth substance is an organic compound having a hole transporting property. The fifth substance is a compound, and the fourth substance is a light-emitting element that exhibits acceptor properties. do.

[0045] Alternatively, in another embodiment of the present invention, in the above structure, the fifth substance and the third substance are the same. It is a light emitting element.

[0046] Alternatively, another embodiment of the present invention includes an anode, a cathode, and an EL layer. The EL layer is located between the electrode and the organic compound and contains an inorganic compound. The inorganic compound is an alkali metal compound. The EL layer is an energy dispersive layer. When analyzed by X-ray analysis, there are areas where the number of fluorine atoms is greater than the number of nitrogen atoms. It is a light-emitting element.

[0047] Alternatively, another embodiment of the present invention is a semiconductor device having the above structure, in which the number of fluorine atoms is 3 times the number of nitrogen atoms. It is a light-emitting element with a luminance of more than 1000 uV.

[0048] Alternatively, another embodiment of the present invention is a light-emitting layer having the above structure, wherein the EL layer has a light-emitting layer containing fluorine. The part where the number of atoms is greater than the number of nitrogen atoms is located between the light-emitting layer and the cathode. .

[0049] Alternatively, another embodiment of the present invention is a light-emitting device having the above structure, wherein the EL layer further includes an electron-transporting layer. The electron transport layer is located between the light emitting layer and the cathode, and has a greater number of fluorine atoms than nitrogen atoms. The light-emitting element is located in the electron transport layer.

[0050] Alternatively, another embodiment of the present invention includes an anode, a cathode, and an EL layer. The EL layer is located between the electrode and the light-emitting layer, and has a light-emitting layer and an electron transport layer. The electron transport layer is located between the electrode and the cathode and contains organic and inorganic compounds. The material is an alkali metal fluoride or an alkaline earth metal fluoride, and is used in the electron transport layer. The concentration of the inorganic compound in the light-emitting element is 50 vol % or more.

[0051] Alternatively, in the above structure, another embodiment of the present invention is a method for manufacturing a semiconductor device comprising: The concentration of the luminescent material is 50 vol % or more and less than 95 vol %.

[0052] Another embodiment of the present invention is a method for manufacturing a semiconductor device according to the above structure, wherein the organic compound has an electron-transporting property. It is a light-emitting element that is an organic compound.

[0053] Another embodiment of the present invention is a compound having the above structure, wherein the organic compound is a π-electron-deficient heteroaromatic compound. It is a light-emitting element that belongs to the ZnO group.

[0054] Another embodiment of the present invention is a compound having the above structure, wherein the organic compound has a bipyridine skeleton. The light-emitting element is an organic compound.

[0055] Another embodiment of the present invention is a compound having the above structure, wherein the organic compound has a phenanthroline skeleton. The light-emitting element is an organic compound having the above structure.

[0056] Alternatively, in the above structure, another embodiment of the present invention is a compound in which the organic compound is 2,9-bis(naphthalene). phthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline, a luminescent dye He is a child.

[0057] Alternatively, another embodiment of the present invention is a semiconductor device having the above structure, wherein the inorganic compound is lithium fluoride, fluorine, or the like. The light-emitting element is either calcium fluoride or magnesium fluoride.

[0058] Another embodiment of the present invention is a light-emitting element and a sensor, an operation button, a speaker, or a light-emitting device. is an electronic device having a microphone and

[0059] Another embodiment of the present invention is a semiconductor device including the above light-emitting element and a transistor or a substrate. It is a light-emitting device.

[0060] Another embodiment of the present invention is a lighting device including the above light-emitting element and a housing.

[0061] Alternatively, another aspect of the present invention is a crystallized alkali metal salt or a crystallized alkali metal salt. The material contains a salt of an earth metal and an organic compound.

[0062] Alternatively, another aspect of the present invention is a crystallized alkali metal fluoride or a crystallized alkali metal fluoride. The material contains a fluoride of an alkaline earth metal and an organic compound.

[0063] Another embodiment of the present invention is a material having the above structure, wherein the organic compound is bipyridine. It is a material that is an organic compound with a skeleton.

[0064] Another embodiment of the present invention is a material having the above structure, wherein the organic compound is a phenanthroline. The material is an organic compound having a thoroline skeleton.

[0065] Another embodiment of the present invention is a material having the above structure, wherein the organic compound is a 2,9- Bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline It is a material that

[0066] Another embodiment of the present invention is a material having the above structure, wherein the material is a crystallized alkali metal. Fluorides of alkaline earth metals or crystallized fluorides of alkaline earth metals are The material is one of calcium and magnesium fluoride.

[0067] Another embodiment of the present invention is a material for a light-emitting element that includes any of the above materials.

[0068] Another aspect of the present invention is a film containing the above-described material.

[0069] Another embodiment of the present invention is a light-emitting element including a layer made of any of the above materials.

[0070] Another embodiment of the present invention is a light-emitting element having the above structure and a housing or a touch sensor. Another embodiment of the present invention is an electronic device having at least one of the above-described structures. The lighting device includes an element and at least one of a housing, a connection terminal, and a protective cover. Furthermore, one embodiment of the present invention is not only a light-emitting device having a light-emitting element, but also an electronic device having a light-emitting device. Therefore, the light-emitting device in this specification includes image display devices, It also refers to a light source (including lighting equipment). exible Printed Circuit), TCP (Tape Carrier) The display module has a printed wiring board attached to the TCP. Display module with a built-in LED or COG (Chip On Glass) type light emitting element A display module in which an IC (integrated circuit) is directly mounted by the method is also one aspect of the present invention. [Effects of the Invention]

[0071] One embodiment of the present invention can provide a light-emitting element with high light extraction efficiency. In one embodiment of the present invention, a light-emitting element including a low refractive index layer can be provided. In one embodiment of the present invention, a light-emitting element with low driving voltage can be provided. According to one embodiment of the present invention, a light-emitting element with reduced power consumption can be provided. In addition, in one embodiment of the present invention, a light-emitting element having high light-emitting efficiency can be provided. Alternatively, in one embodiment of the present invention, a novel light-emitting element can be provided. Alternatively, one aspect of the present invention is to provide a novel electronic device. Another embodiment of the present invention can provide a novel lighting device.

[0072] The description of these effects does not preclude the existence of other effects. It is not necessary to have all of these effects. Effects other than these may be included in the description. It is obvious from the description of the specification, drawings, claims, etc. From this, it is possible to extract other effects. [Brief explanation of the drawings]

[0073] [Figure 1] 1A and 1B are schematic cross-sectional views of a light-emitting element of one embodiment of the present invention and a diagram illustrating an optical path length. [Figure 2] 1A and 1B are schematic cross-sectional views of a light-emitting element of one embodiment of the present invention and a diagram illustrating an optical path length. [Figure 3] 1A and 1B are schematic cross-sectional views of a light-emitting element of one embodiment of the present invention and a diagram illustrating an optical path length. [Figure 4] 1A and 1B are schematic cross-sectional views of light-emitting elements according to embodiments of the present invention and diagrams illustrating correlations between energy levels of light-emitting layers. [Figure 5] 1A and 1B are schematic cross-sectional views of light-emitting elements according to embodiments of the present invention and diagrams illustrating correlations between energy levels of light-emitting layers. [Figure 6] FIG. 1 is a conceptual diagram of an active matrix light-emitting device according to one embodiment of the present invention. [Figure 7] FIG. 1 is a conceptual diagram of an active matrix light-emitting device according to one embodiment of the present invention. [Figure 8] FIG. 1 is a conceptual diagram of an active matrix light-emitting device according to one embodiment of the present invention. [Figure 9] 1 is a schematic diagram of an electronic device according to one embodiment of the present invention. [Figure 10] 1 is a schematic diagram of an electronic device according to one embodiment of the present invention. [Figure 11] FIG. 1 illustrates a lighting device according to one embodiment of the present invention. [Figure 12] FIG. 1 illustrates a lighting device according to one embodiment of the present invention. [Figure 13] FIG. 4 is a diagram illustrating refractive indexes according to an embodiment. [Figure 14] FIG. 10 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 15] FIG. 10 is a graph showing current density-voltage characteristics of a light-emitting element according to an example. [Figure 16] FIG. 10 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 17] FIG. 10 is a diagram illustrating an emission spectrum according to an example. [Figure 18] 10A and 10B are graphs illustrating the relationship between the external quantum efficiency and the peak wavelength of a light-emitting element according to an example. [Figure 19] 10A and 10B are graphs illustrating the relationship between the external quantum efficiency and the peak wavelength of a light-emitting element according to an example. [Figure 20] FIG. 10 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 21] FIG. 10 is a graph showing current density-voltage characteristics of a light-emitting element according to an example. [Figure 22] FIG. 10 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 23] FIG. 10 is a diagram illustrating an emission spectrum according to an example. [Figure 24] FIG. 10 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 25] FIG. 10 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 26] FIG. 10 is a diagram illustrating an emission spectrum according to an example. [Figure 27] FIG. 10 is a graph showing current efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 28] FIG. 10 is a graph showing current density-voltage characteristics of a light-emitting element according to an example. [Figure 29] FIG. 10 is a graph showing external quantum efficiency vs. luminance characteristics of a light-emitting element according to an example. [Figure 30] FIG. 10 is a diagram illustrating an emission spectrum according to an example. [Figure 31] FIG. 1 is a diagram illustrating an NMR chart of a compound according to a reference example. [Figure 32] FIG. 1 is a diagram illustrating an NMR chart of a compound according to a reference example. [Figure 33] FIG. 1 is a diagram illustrating an NMR chart of a compound according to a reference example. [Figure 34] FIG. 1 is a diagram illustrating an NMR chart of a compound according to a reference example. [Figure 35] 1A and 1B are schematic diagrams of light-emitting elements according to one embodiment of the present invention. [Figure 36] FIG. 1 shows the refractive index of a film containing BPhen and lithium fluoride. [Figure 37] Graph showing the relationship between LiF ratio and external quantum efficiency. [Figure 38] A graph showing the relationship between LiF ratio and current at 3V. [Figure 39] FIG. 1 shows EDX spectrum data. [Figure 40] Selected-area electron diffraction analysis of BPhen and LiF mixed films. [Figure 41] Selected area electron diffraction analysis results of BPhen and CaF2 mixed film. [Figure 42] High-magnification TEM image of a BPhen and CaF2 mixed film. [Figure 43] IR measurement results of BPhen and LiF mixed film. [Figure 44] Relationship between the mixing ratio and absorbance of BPhen and LiF mixed films. [Figure 45] 1 is a schematic diagram of a light-emitting element according to one embodiment of the present invention. [Figure 46] FIG. 1 is a conceptual diagram of a passive matrix light-emitting device according to one embodiment of the present invention. [Figure 47] FIG. 1 illustrates a lighting device according to one embodiment of the present invention. [Figure 48] 1A and 1B illustrate electronic devices according to one embodiment of the present invention. [Figure 49] 1A and 1B illustrate electronic devices according to one embodiment of the present invention. [Figure 50] FIG. 1 illustrates a lighting device according to one embodiment of the present invention. [Figure 51] FIG. 1 illustrates a lighting device according to one embodiment of the present invention. [Figure 52] 1A and 1B illustrate an in-vehicle display device and a lighting device according to one embodiment of the present invention. [Figure 53] 1A and 1B illustrate electronic devices according to one embodiment of the present invention. [Figure 54] 1A and 1B illustrate electronic devices according to one embodiment of the present invention. [Figure 55] FIG. 10 is a graph showing luminance-current density characteristics of light-emitting elements 22 to 29 according to an example. [Figure 56] FIG. 10 is a graph showing current efficiency vs. luminance characteristics of light-emitting elements 22 to 29 according to the examples. [Figure 57] FIG. 10 is a graph showing luminance-voltage characteristics of light-emitting elements 22 to 29 according to an example. [Figure 58] FIG. 10 is a graph showing current-voltage characteristics of light-emitting elements 22 to 29 according to the example. [Figure 59] FIG. 10 is a graph showing external quantum efficiency-luminance characteristics of light-emitting elements 22 to 29 according to an example. [Figure 60] FIG. 10 is a graph showing emission spectra of light-emitting elements 22 to 26 according to an example. [Figure 61] FIG. 10 is a graph showing luminance-current density characteristics of light-emitting elements 30 to 36 according to the example. [Figure 62] FIG. 10 is a graph showing current efficiency vs. luminance characteristics of light-emitting elements 30 to 36 according to the example. [Figure 63] FIG. 10 is a graph showing luminance-voltage characteristics of light-emitting elements 30 to 36 according to the example. [Figure 64] 10 is a graph showing current-voltage characteristics of light-emitting elements 30 to 36 according to an example. [Figure 65] FIG. 10 is a graph showing external quantum efficiency vs. luminance characteristics of light-emitting elements 30 to 36 according to the example. [Figure 66] FIG. 2 is a graph showing emission spectra of light-emitting elements 30 to 36 according to an example. [Figure 67] FIG. 10 is a graph showing luminance-current density characteristics of light-emitting elements 37 to 44 according to an example. [Figure 68] FIG. 10 is a graph showing current efficiency-luminance characteristics of light-emitting elements 37 to 44 according to the examples. [Figure 69] FIG. 10 is a graph showing the luminance-voltage characteristics of light-emitting elements 37 to 44 according to an example. [Figure 70] FIG. 10 is a graph showing current-voltage characteristics of light-emitting elements 37 to 44 according to the example. [Figure 71] FIG. 10 is a graph showing external quantum efficiency-luminance characteristics of light-emitting elements 37 to 44 according to an example. [Figure 72] FIG. 10 is a graph showing the emission spectra of light-emitting elements 37 to 44 according to an example. [Figure 73] FIG. 10 is a graph showing luminance-current density characteristics of light-emitting elements 45 to 48 according to an example. [Figure 74] FIG. 10 is a graph showing current efficiency-luminance characteristics of light-emitting elements 45 to 48 according to the example. [Figure 75] FIG. 10 is a graph showing luminance-voltage characteristics of light-emitting elements 45 to 48 according to an example. [Figure 76] FIG. 10 is a graph showing current-voltage characteristics of light-emitting elements 45 to 48 according to the example. [Figure 77] FIG. 10 is a graph showing external quantum efficiency-luminance characteristics of light-emitting elements 45 to 48 according to an example. [Figure 78] FIG. 10 is a graph showing emission spectra of light-emitting elements 45 to 48 according to an example. [Figure 79] FIG. 10 is a graph showing the luminance-current density characteristics of light-emitting elements 49, 50, 51, and 52 according to examples. [Figure 80] FIG. 10 is a graph showing current efficiency-luminance characteristics of light-emitting elements 49, 50, 51, and 52 according to examples. [Figure 81] FIG. 10 is a graph showing the luminance-voltage characteristics of light-emitting elements 49, 50, 51, and 52 according to the examples. [Figure 82] FIG. 10 is a graph showing current-voltage characteristics of light-emitting elements 49, 50, 51, and 52 according to the examples. [Figure 83] FIG. 10 is a graph showing external quantum efficiency-luminance characteristics of light-emitting elements 49, 50, 51, and 52 according to examples. [Figure 84] FIG. 10 is a diagram showing emission spectra of light-emitting elements 49, 50, 51, and 52 according to the examples. [Figure 85] FIG. 10 is a graph showing luminance-current density characteristics of light-emitting elements 53 to 56 according to an example. [Figure 86] FIG. 10 is a graph showing current efficiency vs. luminance characteristics of light-emitting elements 53 to 56 in accordance with the examples. [Figure 87] FIG. 10 is a graph showing luminance-voltage characteristics of light-emitting elements 53 to 56 according to an example. [Figure 88] FIG. 10 is a graph showing current-voltage characteristics of light-emitting elements 53 to 56 according to the example. [Figure 89] FIG. 10 is a graph showing external quantum efficiency vs. luminance characteristics of light-emitting elements 53 to 56 according to an example. [Figure 90] FIG. 10 is a graph showing emission spectra of light-emitting elements 53 to 56 according to an example. [Figure 91] FIG. 10 is a graph showing the viewing angle dependence of light-emitting elements 53 to 56 according to an example. [Figure 92] FIG. 10 is a graph showing normalized luminance-time change characteristics of light-emitting elements 53 to 56 according to an example. [Figure 93] FIG. 10 is a graph showing the external quantum efficiency-luminance characteristics of the light-emitting element 57 according to the example. [Figure 94] FIG. 10 is a diagram illustrating the results of ESR measurements according to the embodiment. [Figure 95]FIG. 10 is a diagram illustrating the results of absorbance measurement according to the example. DETAILED DESCRIPTION OF THE INVENTION

[0074] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the above description, and the embodiments and details thereof may be modified without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the embodiments described below. The terms and conditions of the present invention are not to be construed as being limited to the content.

[0075] In addition, the position, size, range, etc. of each component shown in the drawings etc. are not necessarily shown in order to facilitate understanding. It may not represent the actual position, size, range, etc. Therefore, the disclosed invention The position, size, range, etc. are not necessarily limited to those disclosed in the drawings, etc.

[0076] In addition, in this specification, ordinal numbers such as 1st, 2nd, etc. are used for convenience, In some cases, the order of processes or layers may not be indicated. For example, "first" may be replaced with "second" or " can be appropriately replaced with "third" etc. The ordinal numbers used to identify an aspect of the present invention may not match. be.

[0077] In addition, in this specification and the like, when explaining the configuration of the invention using drawings, the same The reference numerals may be commonly used even among different drawings.

[0078] 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

[0079] The refractive index n is divided into two parts: n Ordinary, which is the refractive index for ordinary rays, and n Ordinary, which is the refractive index for extraordinary rays. n Extra-ordinary and n average are In this specification, when simply referring to "refractive index," if anisotropy analysis is not performed, n If anisotropic analysis is performed, average may be read as n Ordinary. Also, anisotropy is n Ordinary and n Extra-ordinary. It is expressed as the difference between the value obtained by doubling the value of n Ordinary and the value obtained by multiplying n Extra-ordinary. The sum of the dinary values ​​divided by 3 is n average.

[0080] In this specification and the like, room temperature refers to a temperature in the range of 0°C or higher and 40°C or lower.

[0081] (Embodiment 1) In this embodiment, a light-emitting element of one embodiment of the present invention will be described below with reference to FIG.

[0082] FIG. 1A is a schematic cross-sectional view of a light-emitting element 150 of one embodiment of the present invention.

[0083] The light emitting element 150 has a pair of electrodes (electrode 101 and electrode 102), and The EL layer 100 includes at least a light-emitting layer 130 and a low refractive index layer. The organic EL element has a cap layer 145 on the side opposite to the EL layer, which is in contact with the electrode 102. do.

[0084] In FIG. 1A, the low refractive index layer 160 is provided between the light emitting layer 130 and the electrode 101. However, the configuration of the light emitting element 150 is not limited to this. A low refractive index layer 160 may be provided between the light emitting layer 130 and the electrode 102 .

[0085] The refractive index of the low refractive index layer 160 is preferably 1.80 or less, more preferably 1.75 or less. More preferably, it is 1.70 or less.

[0086] 2A, the EL layer 100 includes a hole injection layer 111, The device has functional layers such as a hole transport layer 112, an electron transport layer 118, and an electron injection layer 119. At least one of the hole transport layer 111, the hole transport layer 112, the electron transport layer 118, and the electron injection layer 119 It is preferable that one of them also has the properties of the low refractive index layer 160. In FIG. 2B shows a configuration having the characteristics of the low refractive index layer 160 and the electron injection layer 161. Reference numeral 119 denotes a structure having the properties of the low refractive index layer 160 as well.

[0087] In this embodiment, the electrode 101 has a function of reflecting light, and the electrode 10 2 will be described as an electrode having a function of reflecting light and a function of transmitting light. The configuration of the electrode 101 is not limited to this. The electrode 101 may be configured as an electrode having a light transmitting function, and the electrode 102 may be configured as an electrode having a light reflecting function. No.

[0088] In this embodiment, of the pair of electrodes, electrode 101 is an anode, and electrode 10 Although the description will be given assuming that 2 is a cathode, the configuration of the light emitting element 150 is not limited to this. , the electrode 101 is a cathode, the electrode 102 is an anode, and the layers between the electrodes are stacked in the reverse order. That is, from the anode side, a hole injection layer 111, a hole transport layer 112, and a light emitting layer The layer 130, the electron transport layer 118, and the electron injection layer 119 may be stacked in this order.

[0089] In this embodiment, the arrows shown in FIGS. 1(A), 1(B) and 2(A), 2(B) The direction of the light emitting element 150, that is, the electrode 102 (cathode) side, will be described as the light extraction side. In other words, the light extraction side is the electrode 101 (anode) side. Alternatively, light may be extracted from both the electrode 101 and the electrode 102. When the electrode 101 is used, a cap layer 145 is formed on the opposite side of the EL layer in contact with the electrode 101. When light is extracted from both the electrode 101 and the electrode 102, it is preferable to form the electrode 101 It is preferable to form a cap layer 145 so as to contact the electrode 102 and the electrode 103, respectively.

[0090] The configuration of the EL layer 100 is not limited to the configuration shown in FIG. 1(A), and at least the light-emitting layer 130, and the hole injection layer 111, the hole transport layer 112, the electron transport layer 118, The EL layer 119 and the electron injection layer 119 may or may not be included. 00 reduces the hole or electron injection barrier, improves the hole or electron transport property, Inhibits hole or electron transport, suppresses quenching by electrodes, and inhibits exciton diffusion. It is also possible to have a configuration having a functional layer having a function such as suppressing or being able to suppress the Each layer may be a single layer or may be a laminate of multiple layers.

[0091] <Microcavity structure> In the light-emitting element of one embodiment of the present invention, the electrode 101 has a function of reflecting light. The electrode 102 has a function of reflecting light and a function of transmitting light. By forming the electrode 102 and the EL layer 100 into a micro-optical resonator (microcavity) structure, The light emitted from the light-emitting layer 130 included in the EL layer 100 is resonated between the two electrodes. The light emitted from 102 can be strengthened.

[0092] Specifically, for the peak wavelength λ of light obtained from the light emitting layer 130, The distance between the electrodes 102 is adjusted to be close to mλ / 2 (where m is a natural number). It is also preferable that the distance between the electrodes is within the range of ±50 nm from the ideal distance (mλ / 2). It is preferable that the difference is in the range of ±20 nm, and more preferable that the difference is in the range of ±20 nm. The effect of the cavity can be obtained efficiently.

[0093] In order to amplify the desired light (peak wavelength: λ) obtained from the light emitting layer 130, The optical distance from 101 to the region (light-emitting region) of the light-emitting layer where desired light is obtained, and the electrode 102 and the optical distance from the light emitting layer 130 to the region (light emitting region) where desired light is obtained. It is preferable to adjust it to be close to (2m'-1)λ / 4 (where m' is a natural number). In addition, the optical distance is within the range of ±50 nm from the ideal distance (2 m'-1)λ / 4. It is preferable that the difference is in the range of ±20 nm. In this specification, the light-emitting region is a region where light is emitted. 1A shows the recombination region of holes and electrons in the light-emitting layer 130. 130 shows a case where a light emitting region exists near the center of the image.

[0094] By performing such optical adjustment, the spectrum of a specific monochromatic light obtained from the light-emitting layer 130 can be adjusted. This narrows the line width of the light source, thereby enabling light emission with good color purity to be obtained.

[0095] In order to efficiently obtain light from the light emitting element 150, the light extraction efficiency of the light emitting element 150 must be Here, a low refractive index layer is provided between the light-reflecting layer and the EL layer. It is known that the light extraction efficiency can be improved by providing a low refractive index layer. Many of the materials that can be used for this purpose have low conductivity, and when used in the EL layer, they inhibit conductivity. In this case, the electrode 101 is provided on the opposite side of the EL layer. This increases the number of steps and increases the manufacturing cost.

[0096] Here, the present inventors have placed a light-emitting layer 130 and a low refractive index layer between a pair of electrodes (electrodes 101 and 102). When the refractive index layer 160 is provided and the peak wavelength of the light emitted from the light-emitting layer 130 is λ, As shown in FIG. 1, the low refractive index layer 160 is positioned in a region where the optical distance from the light emitting layer 130 is 0 nm or more and λ / 2 or less. and a cap layer 145 is provided in contact with the electrode 102 on the light extraction side. It has been found that a light-emitting device with improved light extraction efficiency can be provided through a simple manufacturing process.

[0097] The low refractive index layer 160 is provided in a region where the optical distance from the light emitting layer 130 is 0 nm or more and λ / 2 or less. This provides a light extraction effect due to the microcavity structure and introduces a low refractive index layer 160. This is preferable because it is possible to efficiently obtain the light extraction effect. By providing a low refractive index layer 160 on the electrode 101, the electrode 102, or the electrode 103 described later, It is possible to suppress the attenuation of light due to the evanescent mode that occurs near 103. In addition, this configuration prevents the thickness of the EL layer 100 from increasing, thereby reducing the driving voltage. In addition, by adopting this configuration, the electrode 1 having the function of reflecting light from the light-emitting layer can be formed. Since the optical path to the emitting layer can be shortened, the guided mode of the light obtained from the emitting layer Furthermore, the low refractive index layer 160 can be located at an optical distance from the light emitting layer 130. It is more preferable that the distance is set within λ / 4.

[0098] As shown in FIG. 2(A), a low refractive index layer 160 is provided between the anode and the light-emitting layer 130. , the optical path length between the anode side interface of the light emitting layer 130 and the light emitting layer 130 side interface of the low refractive index layer 160 is 0n It is preferable that the optical path length is 0 nm or more and λ / 4 or less. By adopting this configuration, the optical design (the design of the film thickness of each layer of the EL layer 100) This can be easily achieved.

[0099] 2B, a low refractive index layer 160 is formed between the cathode and the light-emitting layer 130. The cathode side interface of the light-emitting layer 130 and the low refractive index layer 160 are provided between the cathode side interface of the light-emitting layer 130 and the low refractive index layer 160. It is preferable that the optical path length is 0 nm or more and λ / 2 or less. More preferably, the optical path length is 0 nm or more and λ / 4 or less. By adopting this configuration, optical design can be facilitated.

[0100] The refractive index of the low refractive index layer 160 is preferably 1.80 or less. The ratio is preferably 0.75 or less, and more preferably 1.70 or less. Therefore, a light emitting element with high efficiency can be provided.

[0101] In addition, it is preferable that the refractive index of the low refractive index layer 160 is lower than the refractive index of the light emitting layer 130. By doing so, attenuation due to the waveguide mode can be suppressed, and the light extraction efficiency can be improved.

[0102] In addition, the hole injection layer 111, the hole transport layer 112, the electron transport layer 118, and the electron injection layer 119 At least one of the refractive indexes is preferably low. In the present invention, a hole injection layer 111, a hole transport layer 112, an electron transport layer 118 and an electron injection layer 119 are It is preferable that at least one of the layers 19 also functions as the low refractive index layer 160. By this, the low refractive index layer 160 can be formed on the EL layer 10 while maintaining the number of manufacturing steps of the conventional light emitting element. Since it can be introduced into the SiO2, it is possible to easily provide a light-emitting device with high light extraction efficiency. can.

[0103] In addition, the hole injection layer 111, the hole transport layer 112, the electron transport layer 118, and the electron injection layer 119 When at least one of them also functions as the low refractive index layer 160, The thickness of the layer is preferably 5 nm or more. A layer having the function of a low refractive index layer is fabricated while maintaining the hole injection property (in the case of the injection layer 111). It is possible.

[0104] In addition, by providing a cap layer 145 on the side opposite to the EL layer 100 in contact with the electrode on the light extraction side, In the light emitting element 150, the electrode 102 is By providing the cap layer 145 so that the refractive index at the interface between the electrode 102 and air is The difference can be reduced, improving the light extraction efficiency. The thickness is preferably 30 nm or less and more preferably 90 nm or less. This allows the cap layer 145 to have good film quality. It is preferable to use a material having a light reflecting function, such as ITO. Electrodes that have the function of transmitting light must be thin, so the film quality is often insufficient. In this case, when a conductive material is used for the cap layer 145, the conductivity may be deteriorated. This improves light extraction efficiency while ensuring electrical conductivity and improving the yield of light-emitting device fabrication. In addition, an organic compound can be suitably used for the cap layer 145. In particular, organic compounds with low absorption in the visible light region can be preferably used. The organic compound used in the L layer 100 can be used as the cap layer 145, so that the EL The cap layer 145 can be formed in the same deposition apparatus or chamber as the layer 100. A cap layer 145 can be deposited thereon.

[0105] 3, an electrode 101 is formed in contact with the EL layer 100. It is preferable to introduce the electrode 103. The electrode 101 has a function of reflecting light. In some cases, materials with reactive surfaces, such as Al or Cu, are used. The surface may be altered by exposure to the atmosphere during the manufacturing process or after the manufacturing process. By fabricating the electrode 103, the deterioration can be suppressed. It is preferable that the material contains indium (In) and tin (Sn). For example, ITO and In addition, it is possible to use thiazol-2-yl acetate (ITSO) as an electrode with a high refractive index. It is also preferable to employ a tongue.

[0106] In the light-emitting element of one embodiment of the present invention, a low refractive index layer is formed between the light-emitting layer 130 and the third electrode 103. Here, the refractive index of the third electrode is the same as that of the layer in contact with the third electrode (hole When the refractive index of the light emitting layer is higher than that of the injection layer 111, the light emitted from the light emitting layer is incident on the third electrode. When the light is reflected at the interface of the layers, it is a fixed-end reflection, so the phase of the reflected light is Therefore, the phase of the microcapacitor between the electrodes 103 and 102 is shifted by π compared to the phase of the light received from the electrodes 103 and 102. In order to form a vitreous structure and improve the light extraction efficiency, the light emitting layer 130 and the electrode 103 The optical distance is preferably in the range of λ / 4±50 nm. The light emitted from the light emitting layer 130 and the light reflected by the electrode 103 can be strengthened. The optical distance between the electrode 103 and the film thickness (λ / 4) is preferably within the range of ±50 nm. It is more preferable that the difference is in the range of ±20 nm. The benefits of this technology can be obtained efficiently.

[0107] Therefore, the hole injection layer 111 in contact with the third electrode 103 also functions as the low refractive index layer 160. By adjusting the optical path length, the effect of the microcavity can be efficiently obtained. Moreover, this configuration is preferable because it allows light emission in the evanescent mode. This is preferable because it can also suppress attenuation of the

[0108] Furthermore, the light emitted from the light-emitting layer 130 and transmitted through the electrode 103 is reflected by the electrode 101. A microcavity structure is formed between the electrode 103 and the electrode 102 to improve the light extraction efficiency. To achieve this, the optical distance (d) between the light-emitting layer 130 and the electrode 103 must be within ±50 nm of the value that satisfies the following formula: It is preferable that the range is .

[0109]

number

[0110] In the light-emitting element according to one embodiment of the present invention, the hole injection layer 111 may function as the low refractive index layer 160. That is, the hole injection layer 111 has a low refractive index (refractive index of 1.80 or less). In order to obtain hole injection properties, the hole injection layer 111 preferably has a thickness of 100 nm to 1100 nm. To achieve this, a substance having electron-accepting properties is mixed with an organic compound having electron-donating properties. The change in hole injection property due to the change in the film thickness is small. By this, the carrier balance of the EL layer is maintained and the electrodes 101 and 103 emit light. Optical adjustment between layers can be easily performed.

[0111] Furthermore, by using an organic compound with a low refractive index for the hole injection layer 111, Even if a substance having electron-accepting properties is used, a layer having hole-injecting properties and a low refractive index can be fabricated. In addition, by using an organic compound with a low refractive index for the hole injection layer 111, the characteristics of the light emitting element can be improved. The light-emitting layer and the layers around the light-emitting layer (light-emitting layer 130, hole transport layer 112) have a particularly large effect on the The light extraction efficiency can be improved even if a material with a low refractive index is not used for the electron transport layer 118). In other words, the selection of organic compounds that can be used in the light-emitting layer and the layers around the light-emitting layer can be improved. That is, the refractive index of the hole injection layer 111 can be reduced, or By using an organic compound with a low refractive index for the hole injection layer 111, the characteristics of the EL layer can be improved. The light extraction efficiency and the effect of the microcavity can be improved while maintaining the above.

[0112] Here, the mixing ratio of the organic compound having electron donating property and the substance having electron accepting property is as follows: The volume ratio of the substance having electron acceptability to the organic compound is 0.01 or more and 0.3 or less. By adopting this configuration, it is possible to use a substance with a high refractive index as the substance having electron accepting properties. Even if the organic compound has a low refractive index, the positive electrode having a low refractive index can be obtained by using an organic compound having a low refractive index. A hole injection layer 111 can be fabricated.

[0113] Furthermore, it is preferable that the refractive index of the organic compound having electron donating properties is 1.80 or less. It is preferably 1.75 or less, and more preferably 1.70 or less. In this way, the hole injection layer 111 can be formed with a low refractive index.

[0114] <Organic compounds with low refractive index and carrier transport properties>

[0115] The layers included in the EL layer (hole injection layer 111, hole transport layer 112, electron transport layer 118 and electron injection layer 119) The interlayer 119 is required to have carrier (electron or hole) transport properties. In the light-emitting device of the embodiment, the low refractive index layer contains a compound having a low refractive index and a carrier transport property. Organic compounds are preferably used.

[0116] The refractive index of a polymer is expressed by the Lorentz-Lorentz equation (Equation (2)) shown below. do.

[0117]

number

[0118] By transforming formula (2), formula (3) can be obtained.

[0119]

number

[0120] In formulas (2) and (3), n is the refractive index, α is the polarizability, N is the number of molecules in a unit volume, and ρ is the density. degrees, N A is Avogadro's number, M is molecular weight, V0 is molar volume, and [R] is atomic refraction.

[0121] From equation (3), in order to reduce the refractive index n, it is sufficient to reduce φ, and from equation (2), To reduce φ, we need to reduce the atomic refraction [R]. In other words, we need to reduce the refractive index n. To reduce this, it is necessary to select an organic compound that has a small atomic refraction [R].

[0122] The above formula is for polymers, so when applied to low molecular weight compounds, the calculated value may differ. Although some discrepancies are expected, the general trend is considered to be similar. The organic compound used in the refractive index layer is selected so that the atomic refraction [R] is small. Furthermore, organic compounds having a π-conjugated system in the molecule have good carrier transport properties. Since the low refractive index layer needs to have carrier transport properties, the organic compound used in the low refractive index layer The material is preferably an organic compound having a small atomic refraction [R] and a π-conjugated system in the molecule. stomach.

[0123] The atomic refraction [R] is a substituent containing fluorine, such as a fluoro group or a trifluoromethyl group, or a cyclo Hexyl group and bonds via aromatic rings 3 The conjugation between aromatic rings, represented by hybrid orbitals, is broken. Therefore, the organic compound used in the low refractive index layer tends to be small. The substance is preferably an organic compound having the above-mentioned substituents or bonds.

[0124] The organic compounds used in the low refractive index layer include those with an aromatic amine skeleton, a pyrrole skeleton, and a fluorene skeleton. and bulky substituents such as methyl, t-butyl, and isopropyl groups. Organic compounds having an aromatic ring having the following structure can also be suitably used. They tend to have a π-conjugated system and a low refractive index.

[0125] <Material> Next, components of a light-emitting element according to one embodiment of the present invention will be described in detail below.

[0126] <Light-emitting layer> As shown in FIG. 1C, the light-emitting layer 130 includes at least a host material 131, and It is preferable that the host material 131 contains a guest material 132. The host material 131 contains an organic compound 131_1. In the light-emitting layer 130, the host material 131 may contain an organic compound 131_2. The guest material 132 is present in the largest amount by weight, and is dispersed in the host material 131. When the host material 132 is a fluorescent compound, the host material 131 (organic compound 132) of the light-emitting layer 130 The S1 level of the guest material (guest 31_1 and organic compound 131_2) of the light-emitting layer 130 It is preferable that the S1 level of the guest material 132 is higher than the S1 level of the guest material 132. In the case of the compound, the host material 131 of the light-emitting layer 130 (organic compound 131_1 and organic compound 131_2) The T1 level of the guest material (guest material 132) in the light-emitting layer 130 is higher than the T1 level of the guest material (guest material 132) in the light-emitting layer 130. It is preferable that the value is higher than that.

[0127] The organic compound 131_1 is a heteroaromatic skeleton having 1 to 20 carbon atoms and containing two or more nitrogen atoms. It is preferable that the compound has a pyrimidine skeleton and a triazine skeleton. As the organic compound 131_1, a material having a higher electron transporting property than a hole transporting property (electron transporting property) is used. Materials) can be used, 1 x 10 -6 cm 2 Materials with electron mobility of ≥ 1000 V It is preferable that there is.

[0128] Specifically, for example, 4,6-bis[3-(phenanthrene-9-yl)phenyl]pyridine 4,6mPnP2Pm, 4,6-bis[3-(4-dibenzothienyl) phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-( 9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm) Heterocyclic compounds with diazine skeletons such as 2-{4-[3-(N-phenyl-9H- (carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl Phenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2-{3-[3-(phenyl) 4,6-diphenyl-2,3-dihydro-2,4 ... Phenyl-1,3,5-triazine (abbreviation: mBnfBPTzn), 2,4,6-tris( Biphenyl-3-yl)-1,3,5-triazine (abbreviation: T2T), 2,4,6-tri Bis[3'-(pyridin-3-yl)-biphenyl-3-yl]-1,3,5-triazine (Abbreviation: TmPPPyTz), 9-[4-(3,5-diphenyl-1H-1,2,4-thiazolinone] 9H-carbazole (abbreviation: CzTAZ(1H)) Heterocyclic compounds having a triazine skeleton, a pyrimidine skeleton, or a triazole skeleton such as Moreover, heterocyclic compounds having such a skeleton have electron transport properties. The materials mentioned here have a high conductivity of 1×10 -6 cm 2 / V It is a substance that has an electron mobility of 1000 s or more. It is a substance that has a higher electron transporting property than a hole transporting property. If necessary, materials other than those mentioned above may be used.

[0129] In addition, organic compounds 131_1 include pyridine derivatives, pyrazine derivatives, and pyridazine derivatives. Conductors, bipyridine derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, phenane Compounds such as thiazolinone derivatives and purine derivatives can also be suitably used. 1x10 -6 cm 2 It is preferable that the material has an electron mobility of .gtoreq.Vs. stomach.

[0130] Specifically, for example, bathophenanthroline (abbreviation: BPhen), 2,9-bis(naphthalene) NBP Heterocyclic compounds with a pyridine skeleton, such as hen and bathocuproine (BCP) and 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxa Sarin (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophene-4- 2mDBTBP DBq-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]quinoxa Phosphorus (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl) phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), and , 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxa Phosphorus (abbreviation: 6mDBTPDBq-II), 2-[3-(3,9'-bi-9H-carbazo (2mCzCzPD)dibenzo[f,h]quinoxaline (abbreviation: 2mCzCzPD) Heteroaromatic compounds with pyrazine skeletons such as 3,5-bis[3-(9H-carbonyl)-2-(methylphenyl)-2-(2- ... 1,3,5-(2-pyridyl)-2-phenyl]pyridine (abbreviation: 35DCzPPy) Pyridines such as tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB) Heterocyclic compounds having a skeleton can also be used. ) (abbreviation: PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co -(pyridine-3,5-diyl)] (abbreviation: PF-Py), poly[(9,9-dioctyl fluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] It is also possible to use a polymer compound such as PF-BPy. Any substance other than those mentioned above may be used as long as it has a high electron transporting property.

[0131] The organic compound 131_2 is a heteroaromatic skeleton containing two or more nitrogen atoms and having 1 to 20 carbon atoms. In particular, a nitrogen-containing five-membered heterocyclic skeleton is preferred. For example, an imidazole skeleton , triazole skeleton, and tetrazole skeleton. As the material, a material having a higher hole transporting property than an electron transporting property (hole transporting material) can be used. 1×10 -6 cm 2 It is preferable that the material has a hole mobility of .gtoreq. / Vs. The hole transporting material may be a polymer compound.

[0132] Specifically, for example, 3-(4-biphenylyl)-4-phenyl-5-(4-tert- butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 9-[4-(4,5- Diphenyl-4H-1,2,4-triazol-3-yl)phenyl]-9H-carbazo CzTAZ1, 2,2',2''-(1,3,5-benzenetriyl)trimethylol Tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(di benzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole ( Abbreviated as mDBTBIm-II) etc. can be used.

[0133] As the organic compound 131_2, other nitrogen-containing five-membered heterocyclic skeleton or tertiary amine skeleton Compounds having a pyrrole skeleton or an aromatic alkyl group can also be suitably used. Examples include indole derivatives, carbazole derivatives, triarylamine skeletons, etc. The organic compound 131_2 is a compound that has a hole rather than an electron. A material with high transport properties (hole transport material) can be used, and the -6 cm 2 / Vs It is preferable that the hole transport material is a polymer having a hole mobility of at least 1000 .mu.m. It may also be a compound.

[0134] As the material having high hole transporting properties, specifically, aromatic amine compounds such as N, N'-Di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviated as DT DPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenyla N,N'-bis[4-[bis(3-methylphenyl) {N,N'-diphenyl-(1,1'-biphenyl)-4,4' -diamine (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylamino) [phenyl]-N-phenylamino]benzene (abbreviation: DPA3B), etc. .

[0135] Specific examples of carbazole derivatives include 3-[N-(4-diphenylamino phenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA1 ), 3,6-bis[N-(4-diphenylaminophenyl)-N-phenylamino]-9 -phenylcarbazole (abbreviation: PCzDPA2), 3,6-bis[N-(4-diphenyl [N-(1-naphthyl)amino]-9-phenylcarbazole (abbreviation :PCzTPN2), 3-[N-(9-phenylcarbazol-3-yl)-N-phenyl 3,6-bis[N- (9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazol PCzPCA2, 3-[N-(1-naphthyl)-N-(9-phenylcarbazone] [carbazol-3-yl]amino]-9-phenylcarbazole (abbreviation: PCzPCN1) , 4,4'-bis(9-carbazolyl)-2,2'-dimethyl-biphenyl (abbreviation: dm CBP) and the like.

[0136] Other carbazole derivatives include 4,4'-di(N-carbazolyl)biphene. Nyl (abbreviation: CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzoyl Zene (abbreviation: TCPB), 9-[4-(10-phenyl-9-anthryl)phenyl]- 9H-Carbazole (abbreviation: CzPA), 7-[4-(10-phenyl-9-anthryl )phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA)1, 4-Bis[4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene Zeng et al. can be used.

[0137] Also, N,N-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl] ]-9H-carbazol-3-amine (abbreviation: CzA1PA), 4-(10-phenyl- 9-Anthryl)triphenylamine (abbreviation: DPhPA), 4-(9H-carbazole -9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl] Phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), N,9-diphenyl -N-{4-[4-(10-phenyl-9-anthryl)phenyl]phenyl}-9H- Carbazol-3-amine (abbreviation: PCAPBA), N,9-diphenyl-N-(9,1 0-Diphenyl-2-anthryl)-9H-carbazol-3-amine (abbreviation: 2PCA) PA), 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9 H-carbazole (abbreviation: PCzPA), 3,6-diphenyl-9-[4-(10-phenyl) N-(9-anthryl)phenyl]-9H-carbazole (abbreviation: DPCzPA), N,N',N',N'',N'',N''',N'''-octaphenyldibenzo[g, p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), etc. can be done.

[0138] In addition, poly(N-vinylcarbazole) (abbreviation: PVK) and poly(4-vinyltriphenyl ether) Nylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenyl amino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide]( abbreviation: PTPDMA), poly[N,N'-bis(4-butylphenyl)-N,N'-bis Polymer compounds such as [(phenyl)benzidine] (abbreviation: Poly-TPD) can also be used. can.

[0139] Furthermore, examples of materials with high hole transport properties include 4,4'-bis[N-(1-naphthyl)-2-methyl-2-propanol]. N,N'-(phenyl)-N-phenylamino]biphenyl (abbreviation: NPB or α-NPD) Bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4, 4'-diamine (abbreviation: TPD), 4,4',4''-tris(carbazol-9-yl) ) triphenylamine (abbreviation: TCTA), 4,4',4''-tris[N-(1-naphthyl) 4,4-Triphenylamine (abbreviation: 1'-TNATA) ',4''-Tris(N,N-diphenylamino)triphenylamine (abbreviation: TDAT A), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino] Triphenylamine (abbreviation: MTDATA), 4,4'-bis[N-(spiro-9,9' -bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4 -phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenyl Nylamine (abbreviation: mBPAFLP), N-(9,9-dimethyl-9H-fluorene-2 -yl)-N-{9,9-dimethyl-2-[N'-phenyl-N'-(9,9-dimethyl -9H-fluoren-2-yl)amino]-9H-fluoren-7-yl}phenylamino N-(9,9-dimethyl-2-diphenylamino-9H- Fluoren-7-yl)diphenylamine (abbreviation: DPNF), 2-[N-(4-diphenyl) N-phenylaminophenyl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: DPASF), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl) Triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9- Phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1B) P), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl) Triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''- (9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCBN BB), 4-phenyldiphenyl-(9-phenyl-9H-carbazol-3-yl)a amine (abbreviation: PCA1BP), N,N'-bis(9-phenylcarbazol-3-yl) -N,N'-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N,N', N''-triphenyl-N,N',N''-tris(9-phenylcarbazole-3-yl) N-(4-biphenyl)benzene-1,3,5-triamine (abbreviation: PCA3B) -N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-chlor PCBiF, N-(1,1'-biphenyl-4-yl) -N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-di Methyl-9H-fluoren-2-amine (abbreviation: PCBBiF), 9,9-dimethyl-N -phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl] Fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl -9H-carbazol-3-yl)phenyl]spiro-9,9'-bifluorene-2-a PCBASF, 2-[N-(9-phenylcarbazol-3-yl)-N -phenylamino]spiro-9,9'-bifluorene (abbreviation: PCASF), 2,7-bi Spiro-9,9'-[N-(4-diphenylaminophenyl)-N-phenylamino]spiro Bifluorene (abbreviation: DPA2SF), N-[4-(9H-carbazol-9-yl)fluorene] N,N'-phenyl]-N-(4-phenyl)phenylaniline (abbreviation: YGA1BP), Bis[4-(carbazol-9-yl)phenyl]-N,N'-diphenyl-9,9-di Aromatic amine compounds such as methylfluorene-2,7-diamine (abbreviation: YGA2F) Also, 3-[4-(1-naphthyl)-phenyl]-9-phenyl can be used. -9H-carbazole (abbreviation: PCPN), 3-[4-(9-phenanthryl)-phenyl 3,3'-bis(9- phenyl-9H-carbazole) (abbreviation: PCCP), 1,3-bis(N-carbazolyl ) benzene (abbreviation: mCP), 3,6-bis(3,5-diphenylphenyl)-9-phenyl Nylcarbazole (abbreviation: CzTP), 3,6-di(9H-carbazol-9-yl)- 9-phenyl-9H-carbazole (abbreviation: PhCzGI), 2,8-di(9H-carbazole) amine compounds such as benzothiazolinone (Cz2DBT), Among the compounds mentioned above, those having a pyrrole skeleton, an aromatic Compounds having an aromatic amine skeleton are preferred because they are stable and highly reliable. The compound having the formula (I) has high hole transporting properties and contributes to reducing the driving voltage.

[0140] In the light-emitting layer 130, the guest material 132 is not particularly limited, but may be a fluorescent material. The compounds include anthracene derivatives, tetracene derivatives, chrysene derivatives, phenanthrene derivatives, pyrene derivatives, perylene derivatives, stilbene derivatives, acridone derivatives, Marine derivatives, phenoxazine derivatives, phenothiazine derivatives, etc. are preferred, and examples thereof include the following: The following materials can be used:

[0141] Specifically, 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2 ,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl -9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2 BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoro (9-phenyl)pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn) , N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H -fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMem FLPAPrn), N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl )phenyl]-N,N'-bis(4-tert-butylphenyl)pyrene-1,6-diazo amine (abbreviation: 1,6tBu-FLPAPrn), N,N'-bis[4-(9-phenyl- 9H-fluoren-9-yl)phenyl]-N,N'-diphenyl-3,8-dicyclohexyl Xylpyrene-1,6-diamine (abbreviation: ch-1,6FLPAPrn), N,N'-biphenyl bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbe 4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl) -4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA) , 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-anthracene) N,9-diphenyl-N-[4- (10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation Name: PCAPA), Perylene, 2,5,8,11-tetra(tert-butyl)perylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl- 9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), N,N' '-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene) Bis[N,N',N'-triphenyl-1,4-phenylenediamine] (abbreviation: DPAB PA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl] phenyl]-9H-carbazol-3-amine (abbreviation: 2PCAPPA), N-[4-(9 ,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1 ,4-Phenylenediamine (abbreviation: 2DPAPPA), N,N,N',N',N'',N '',N''',N'''-Octaphenyldibenzo[g,p]chrysene-2,7,10 ,15-tetraamine (abbreviation: DBC1), Coumarin 30, N-(9,10-diphenyl -2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2 PCAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthracene] aryl]-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPh A), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl -1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(1,1 '-biphenyl-2-yl)-2-anthryl]-N,N',N'-triphenyl-1, 4-Phenylenediamine (abbreviation: 2DPABPhA), 9,10-bis(1,1'-biphenyl) (9H-carbazol-9-yl)phenyl)-N-[4-(9H-carbazol-9-yl)phenyl]-N- Phenylanthracene-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenyl Dianthracen-9-amine (abbreviation: DPhAPhA), Coumarin 6, Coumarin 545T , N,N'-diphenylquinacridone (abbreviation: DPQd), rubrene, 2,8-di-te rt-Butyl-5,11-bis(4-tert-butylphenyl)-6,12-diphenyl Tetrathracene (abbreviation: TBRb), Nile Red, 5,12-bis(1,1'-biphenyl) 2-(2-(2-phenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), [4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-yl 2-(2-methyl-6-[(2,3-dimethyl- ... ,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl ]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N ',N'-Tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methyl phenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: p -mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl 2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl )ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI) , 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3, 6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl] -4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2, 6-Bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-yl 2-(2,6-bis[2-(8- Methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H -benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}p Dopanedinitrile (abbreviation: BisDCJTM), 5,10,15,20-tetraphenyl Bisbenzo[5,6]indeno[1,2,3-cd:1',2',3'-lm]perylene , etc.

[0142] The guest material 132 (phosphorescent compound) is iridium, rhodium, or platinum-based Organometallic complexes or metal complexes are mentioned, among which organic iridium complexes, e.g., iridium The orthometalated ammonium complex is preferred. The orthometalated ligand is 4H-triazolium. 1H-triazole ligands, 1H-triazole ligands, imidazole ligands, pyridine ligands, pyrimidine ligands Examples of the metal complexes include quinazine, pyrazine, and isoquinoline ligands. Examples of the platinum complex include a platinum complex having a porphyrin ligand.

[0143] Examples of substances having a blue or green emission peak include tris{2-[5-(2 -methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazo 3-yl-κN 2 ]phenyl-κC}iridium(III) (abbreviation: Ir(mpp tz-dmp)3), tris(5-methyl-3,4-diphenyl-4H-1,2,4-trimethyl- Triazolato)iridium(III) (abbreviation: Ir(Mptz)3), tris[4-(3- Biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]i Iridium(III) (abbreviation: Ir(iPrptz-3b)3), tris[3-(5-biphenyl] (phenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]irid Ir(III) (abbreviated as Ir(iPr5btz)3), a 4H-triazole skeleton and organometallic iridium complexes with tris[3-methyl-1-(2-methylphenyl) -5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: Ir (Mptz1-mp)3), tris(1-methyl-5-phenyl-3-propyl-1H- 1,2,4-Triazolate)iridium(III) (abbreviation: Ir(Prtz1-Me) 3) and fac-triazole-based organometallic iridium complexes. S[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]isopropyl Iridium(III) (abbreviation: Ir(iPrpmi)3), tris[3-(2,6-dimethyl phenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(I II) (Abbreviation: Ir(dmpimpt-Me)3)tris{2-[1-(4-cyano-2 ,6-diisobutylphenyl)-1H-benzimidazol-2-yl-κN 3 ]Feni Iridium(III) (abbreviated as Ir(pbi-diBuCNp)3) Organometallic iridium complexes with imidazole skeletons and bis[2-(4',6'-difluoromethyl]-2-(4-fluoromethyl) ... (O-phenyl)pyridinato-N,C 2’ ]iridium(III) tetrakis(1-pyrazoline) aryl)borate (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl)pi Lysinato-N,C 2’ ] Iridium(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C 2’ } Iridium(III) picolinate (abbreviation: Ir(CF3ppy)2(pic)), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ]Iridium (I II) Electron-withdrawing groups such as acetylacetonate (abbreviation: FIr(acac)) An example is an organometallic iridium complex having a phenylpyridine derivative as a ligand. Among them, 4H-triazole skeleton, 1H-triazole skeleton and imidazole skeleton are Organometallic iridium complexes with such nitrogen-containing five-membered heterocyclic skeletons have high triplet excitation energies. It is particularly preferable because it has excellent reliability and luminous efficiency.

[0144] Furthermore, examples of substances having a green or yellow emission peak include tris(4-methylphenyl) Ir(mppm)3, Tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: I r(tBuppm)3), (acetylacetonato)bis(6-methyl-4-phenylpyridine) Iridium(III) (abbreviation: Ir(mppm)2(acac)), (acetylacetonate ruacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium( III) (Abbreviation: Ir(tBuppm)2(acac)), (acetylacetonato)bis [4-(2-norbornyl)-6-phenylpyrimidinato]iridium(III) (abbreviation : Ir(nbppm)2(acac)), (acetylacetonato)bis[5-methyl-6 -(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: Ir(mpmppm)2(acac)), (acetylacetonato)bis{4,6-dimethyl 2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN 3 ]phenyl- κC}iridium(III) (abbreviation: Ir(dmppm-dmp)2(acac)), ( acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III)( Organometallic iridium compounds with pyrimidine skeletons, such as Ir(dppm)2(acac) complexes and (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazine Iridium(III) (abbreviation: Ir(mppr-Me)2(acac)), (acetyl arylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridide Pyrazine skeletons such as Ir(III) (abbreviation: Ir(mppr-iPr)2(acac)) Organometallic iridium complexes and tris(2-phenylpyridinato-N,C 2’ ) Iridium(III) (abbreviation: Ir(ppy)3), bis(2-phenylpyridinato-N ,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(ppy)2(ac ac)), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: Ir(bzq)2(acac)), tris(benzo[h]quinolinato)iridium Ir(III) (abbreviation: Ir(bzq)3), tris(2-phenylquinolinato-N,C 2 ’ ) Iridium(III) (abbreviation: Ir(pq)3), bis(2-phenylquinolinato- N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(pq)2(ac Organometallic iridium complexes with pyridine skeletons such as bis(2,4-difluoromethyl) Phenyl-1,3-oxazolato-N,C 2’ ) Iridium(III) acetylacetoner Ir(dpo)2(acac)), bis{2-[4'-(perfluorophenyl) (phenyl)pyridinato-N,C 2’}Iridium(III) acetylacetonate( Abbreviation: Ir(p-PF-ph)2(acac)), bis(2-phenylbenzothiazol- -N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(bt)2(a In addition to organometallic iridium complexes such as tris(acetylacetonato)(monophenyl) Anthroline) terbium(III) (abbreviation: Tb(acac)3(Phen)) Among the above, organometallic iridium complexes having a pyrimidine skeleton are Dium complexes are particularly preferred because they are remarkably excellent in reliability and luminous efficiency.

[0145] Furthermore, examples of substances having a yellow or red emission peak include (diisobutyryl) Methanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(II I) (abbreviation: Ir(5mdppm)2(dibm)), bis[4,6-bis(3-methyl [phenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: Ir (5mdppm)2(dpm)), bis[4,6-di(naphthalen-1-yl)pyrimidinyl] Nato](dipivaloylmethanato)iridium(III) (abbreviation: Ir(d1npm)2( Organometallic iridium complexes with pyrimidine skeletons, such as (acetylacetonyl acetone) Iridium(III) (abbreviation: I r(tppr)2(acac)), bis(2,3,5-triphenylpyrazinate)(dipyr Valoylmethanato)iridium(III) (abbreviation: Ir(tppr)2(dpm)), ( Acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]i Ir(Fdpq)2(acac) and other pyrazine-based compounds Organometallic iridium complexes and tris(1-phenylisoquinolinato-N,C 2’ ) Iridium(III) (abbreviation: Ir(piq)3), bis(1-phenylisoquinolinato) -N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(piq)2( In addition to organometallic iridium complexes with pyridine skeletons such as acac), 2,3,7, 8,12,13,17,18-Octaethyl-21H,23H-porphyrin platinum(II) ) (abbreviation: PtOEP) and tris(1,3-diphenyl-1,3-propanediol). Eu(DB)(propanedionato)(monophenanthroline)europium(III) M)3(Phen)), tris[1-(2-thenoyl)-3,3,3-trifluoroacetate [Tonato](monophenanthroline)europium(III) (abbreviation: Eu(TTA)3( Among the above, rare earth metal complexes such as pyrimidine skeletons are Organometallic iridium complexes having the above structure are particularly preferred because they are remarkably excellent in reliability and luminous efficiency. In addition, organometallic iridium complexes with a pyrazine skeleton can emit red light with good chromaticity. can be done.

[0146] The light-emitting material contained in the light-emitting layer 130 is a material capable of converting triplet excitation energy into light. The material capable of converting triplet excitation energy into luminescence is preferably a phosphorescent material. In addition to the thermally activated delayed fluorescence compounds, Therefore, phosphorescence The term "thermally activated delayed fluorescent compound" may be read as "thermally activated delayed fluorescent material." A thermally activated delayed fluorescent material is a material that has a triplet excitation energy level and a singlet excitation energy level. The difference between the triplet and singlet excited states is small, and reverse intersystem crossing allows the energy to be transferred from the triplet excited state to the singlet excited state. Therefore, the triplet excited state can be converted into a small amount of thermal energy. Therefore, upconversion (reverse intersystem crossing) from the singlet excited state is possible. Furthermore, thermally activated delayed fluorescence can be efficiently obtained. The conditions for this are the energies of the triplet and singlet excited energy levels. The difference is preferably greater than 0 eV and not greater than 0.2 eV, more preferably greater than 0 eV and not greater than 0 The most notable features are that the energy density is less than 0.1 eV.

[0147] When the thermally activated delayed fluorescent material is composed of one kind of material, for example, the following material is used: It is possible.

[0148] First, fullerene and its derivatives, acridine derivatives such as proflavine, and eosin are listed. In addition, magnesium (Mg), zinc (Zn), cadmium (Cd), tin (S n), platinum (Pt), indium (In), or palladium (Pd) Examples of the metal-containing porphyrin include protoporphyrin. Porphyrin-tin fluoride complex (SnF2(Proto IX)), mesoporphyrin-fluoride Tin complex (SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (Sn F2 (Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride Complex (SnF2(Copro III-4Me)), Octaethylporphyrin-Fluoride Tin complex (SnF2(OEP)), etioporphyrin-tin fluoride complex (SnF2(E tio I)), octaethylporphyrin-platinum chloride complex (PtCl2OEP), etc. It can be obtained.

[0149] In addition, as a thermally activated delayed fluorescent material composed of one kind of material, π-electron-rich heteroaromatic Heterocyclic compounds having an aromatic ring and a π-electron-deficient heteroaromatic ring can also be used. is 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3- a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol {4,6-diphenyl-1,3,5-triazine (PC CzPTzn), 2-[4-(10H-phenoxazin-10-yl)phenyl]-4, 6-Diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5- Phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl PPZ-3TPT, 3-(9,9-dimethyl- 9H-Acridine-10-yl)-9H-xanthen-9-one (Abbreviation: ACRXTN) , bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10'H-spiro[acridine -9,9'-anthracene]-10'-one (abbreviation: ACRSA), etc. The heterocyclic compounds have a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring, Among them, a skeleton having a π-electron-deficient heteroaromatic ring is preferred. Among them, diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton) or triazine skeleton The azine skeleton is preferred because it is stable and reliable. Among the skeletons that have such structures, acridine skeleton, phenoxazine skeleton, thiophene skeleton, and furan skeleton are Since the pyrrole skeleton and the pyrrole skeleton are stable and reliable, any of the skeletons can be used. It is preferable that the pyrrole skeleton has one or more of the following. skeleton, a carbazole skeleton, and 3-(9-phenyl-9H-carbazol-3-yl)- A 9H-carbazole skeleton is particularly preferred. The substance in which the π-electron-rich heteroaromatic ring is directly bonded to the π-electron-deficient heteroaromatic ring exhibits the donor property of the π-electron-rich heteroaromatic ring. The acceptor properties of the heteroaromatic rings are both strong, and the energy levels of the singlet excited state and triplet excited state are This is particularly preferable because the difference between the energy level of the excited state and the energy level of the excited state is small.

[0150] In addition, in the light-emitting layer 130, materials other than the host material 131 and the guest material 132 are It may have.

[0151] The material that can be used for the light-emitting layer 130 is not particularly limited, but examples thereof include anthracene, Helical derivatives, phenanthrene derivatives, pyrene derivatives, chrysene derivatives, dibenzo[g, p] chrysene derivatives and other condensed polycyclic aromatic compounds, specifically 9,10-diphenyl Phenylanthracene (abbreviation: DPAnth), 6,12-dimethoxy-5,11-diphenyl Nilcrysene, 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: D PPA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 2-tert -butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 9, 9'-Bianthryl (abbreviation: BANT), 9,9'-(stilbene-3,3'-diyl) Diphenanthrene (abbreviation: DPNS), 9,9'-(stilbene-4,4'-diyl)di Phenanthrene (abbreviation: DPNS2), 1,3,5-tri(1-pyrenyl)benzene (abbreviation Among these and other known substances, the above-mentioned Singlet or triplet excited energy levels higher than the excited energy level of the guest material 132 One or more substances having an excitation energy level may be selected and used.

[0152] In addition, for example, a compound having a heteroaromatic skeleton such as an oxadiazole derivative may be used as the light-emitting layer 1. 30. Specifically, for example, 2-(4-biphenylyl)-5-(4 -tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD) and 1 ,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazole- 2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-o 4,9H-(2-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 4'-Bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOS) and the like heterocyclic compounds.

[0153] In addition, metal complexes having heterocycles (e.g., zinc and aluminum-based metal complexes) emit light. For example, quinoline ligands, benzoquinoline ligands, oxalyl ligands, Examples include metal complexes having a thazole ligand or a thiazole ligand. For example, tris(8-quinolinolato)aluminum(III) (abbreviation: Alq), tris(8-quinolinolato)aluminum(III) Bis(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq3), Bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq2 ), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum ( III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq) and metal complexes having a quinoline skeleton or a benzoquinoline skeleton, such as: In addition, bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnP BO), bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnB Metal complexes with oxazole or thiazole ligands such as TZ are also used. It is possible.

[0154] The light-emitting layer 130 may be composed of two or more layers. When the light-emitting layer 130 is formed by laminating the first light-emitting layer and the second light-emitting layer in this order from the hole transport layer side, a substance having hole transport properties is used as a host material for the first light-emitting layer, and a substance having hole transport properties is used as a host material for the second light-emitting layer In addition, a structure in which a substance having an electron transporting property is used as the first light-emitting layer and the second light-emitting layer is also available. The light-emitting materials in the optical layer and the optical layer may be the same or different materials, and they may emit light of the same color. Even if the material has a function of emitting light, it may have a function of emitting light of different colors. The two light-emitting layers may contain light-emitting materials that emit light of different colors. By using each of these layers, multiple light emissions can be obtained simultaneously. It is preferable to select a light-emitting material for each light-emitting layer so that the resulting light emitted will be white.

[0155] The light-emitting layer 130 can be formed by a deposition method (including a vacuum deposition method), an ink-jet method, a coating method, a grating method, or the like. It can be formed by a method such as rabbet printing. In addition to the above-mentioned materials, quantum dots and the like can also be used. Even if the inorganic compound or polymer compound (oligomer, dendrimer, polymer, etc.) good.

[0156] <Hole injection layer> The hole injection layer 111 is formed by injecting holes from one of the pair of electrodes (electrode 101 or electrode 102). It has the function of promoting hole injection by reducing the injection barrier, and has, for example, electron donating properties Formed from transition metal oxides, phthalocyanine derivatives, aromatic amines, heteropolyacids, etc. Examples of transition metal oxides include titanium oxide, vanadium oxide, tantalum oxide, Molybdenum oxide, tungsten oxide, rhenium oxide, ruthenium oxide, chromic acid Examples of the transition metal oxide include oxides of zirconium, hafnium, and silver. The oxide has excellent electron-accepting properties and can be easily formed into a film by vacuum deposition or wet method. As the phthalocyanine derivative, phthalocyanine and metal phthalocyanine are preferred. Aromatic amines include benzidine derivatives and phenylenediamine derivatives. Polymer compounds such as polythiophene and polyaniline can also be used. For example, the self-doped polythiophene poly(ethylenedioxythiophene ) / poly(styrene sulfonic acid) are typical examples. , phosphomolybdic acid, phosphotungstic acid, silicomolybdic acid, silicotungstic acid, etc. Heteropolyacids and polymer compounds can be easily formed into films by a wet method. This is preferable.

[0157] The hole injection layer 111 may be formed by using a substituent, skeleton, or the like that reduces the atomic refraction [R] as described above. a composite material of a hole transporting material having a hole transporting property or a chemical bond thereto and the above-mentioned material exhibiting electron accepting property; By using such a structure, it is possible to obtain a layer having hole injection and transport properties. As an organic material having electron-accepting properties, a layer with a low refractive index can be formed. ,7,8,8-Tetracyanoquinodimethane (abbreviation: TCNQ), 7,7,8,8-tetra Cyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ), 1, 3,4,5,7,8-Hexafluorocyano-naphthoquinodimethane (abbreviation: F6TCNN) Q) can be preferably used. A stack of layers containing the material may be used. The organic materials that exhibit electron-accepting properties include the above-mentioned TCNQ, In addition to F4TCNQ and F6TCNNQ, quinodimethane derivatives, chloranil derivatives, and hexafluorobenzoates Examples of organic acceptors include sazatriphenylene derivatives. , chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12 -Hexaazatriphenylene (abbreviation: HAT-CN) and other electron-withdrawing groups (halogen groups and sialic acid groups) Radialene derivatives with electron-withdrawing groups include is preferred because it has a very high electron-accepting property, and specifically, α,α',α''-1,2,3- Chlopropanetriylidenetris[4-cyano-2,3,5,6-tetrafluorobenzene acetonitrile], α,α',α''-1,2,3-cyclopropanetriylidenetri bis[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetate nitrile], α,α',α''-1,2,3-cyclopropanetriylidenetris[2 , 3,4,5,6-pentafluorobenzeneacetonitrile]. Transition metals, such as titanium, vanadium, tantalum, molybdenum, tungsten, rhenium Uses substances containing oxygen, such as ruthenium, chromium, zirconium, hafnium, and silver. Specifically, titanium oxide, vanadium oxide, tantalum oxide, molybdenum oxide, Density oxide, Tungsten oxide, Rhenium oxide, Ruthenium oxide, Chromium oxide, Zirconium oxide, hafnium oxide, silver oxide, phosphomolybdic acid, molybdenum bromide Among them, molybdenum oxide is stable in the atmosphere. It is preferred because it has low hygroscopicity and is easy to handle.

[0158] As described above, the hole transport material having a low refractive index used in the hole injection layer 111 is sp 3 Organic compounds with structures that break the conjugation between aromatic rings, such as bonds, and bulky substituents An organic compound having an aromatic ring with a substituent can be preferably used. Such compounds tend to have poor carrier transport properties and have been conventionally unsuitable for hole injection layers. On the other hand, the above-mentioned simple substance containing a transition metal and oxygen has the effect of increasing hole injection. However, the refractive index is high. Oxygen-containing materials are used as electron-accepting materials in combination with hole-transporting materials with low refractive index. When the compound is used in the hole injection layer 111, the hole injection can be performed while keeping the refractive index of the hole injection layer 111 low. In other words, this configuration eliminates the disadvantages of both. These materials can cancel each other out and only the benefits can be realized. This is thought to be due to the high electron-accepting properties of the substance, and the ability to inject holes can be ensured by adding a small amount. .

[0159] As the hole transporting material, a material having a higher hole transporting property than an electron transporting property can be used. x10 -6 cm 2 It is preferable that the material has a hole mobility of .gtoreq. / Vs. As described above, the hole transport material preferably has a refractive index of 1 or more and 1.75 or less. It is preferably 1 or more and 1.73 or less, and more preferably 1 or more and 1.70 or less. Specifically, the aromatic amines listed as hole transport materials that can be used in the light-emitting layer 130 are It is possible to use carbazole derivatives, aromatic hydrocarbons, stilbene derivatives, etc. However, it is particularly preferred that the compound has a heteroaromatic skeleton containing two or more nitrogen atoms and having 1 to 20 carbon atoms. A nitrogen-containing five-membered heterocyclic skeleton is preferred. The hole transport material may also be a polymer compound. stomach.

[0160] Other examples of hole transport materials include aromatic hydrocarbons, such as 2-tert -butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 2- tert-Butyl-9,10-di(1-naphthyl)anthracene, 9,10-bis(3, 5-diphenylphenyl)anthracene (abbreviation: DPPA), 2-tert-butyl-9 ,10-bis(4-phenylphenyl)anthracene (abbreviation: t-BuDBA), 9,1 0-Di(2-naphthyl)anthracene (abbreviation: DNA), 9,10-diphenylanthracene 2-tert-butylanthracene (abbreviation: DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAn th), 9,10-bis(4-methyl-1-naphthyl)anthracene (abbreviation: DMNA) , 2-tert-butyl-9,10-bis[2-(1-naphthyl)phenyl]anthracene 9,10-bis[2-(1-naphthyl)phenyl]anthracene, 2,3,6,7- Tetramethyl-9,10-di(1-naphthyl)anthracene, 2,3,6,7-tetramethyl 9,10-di(2-naphthyl)anthracene, 9,9'-bianthryl, 10,1 0'-Diphenyl-9,9'-bianthryl, 10,10'-bis(2-phenylphenyl) 10,10'-bis[(2,3,4,5,6-pentafluorophenyl)-9,9'-bianthryl, (phenyl)phenyl]-9,9'-bianthryl, anthracene, tetracene, rubrene, perylene, 2,5,8,11-tetra(tert-butyl)perylene, etc. In addition, pentacene, coronene, etc. can also be used. -6 cm 2 / Vs or more, and an aromatic hydrocarbon having 14 to 42 carbon atoms. It is more preferable to use

[0161] 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.

[0162] Also, 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]fluoren phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), 4,4',4''-(benzyl) (benzophenone-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), 1,3,5-Tri(dibenzothiophen-4-yl)-benzene (abbreviation: DBT3P-I I), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl) phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl 6-phenyldibenzothiophene (abbreviation) Name: DBTFLP-IV), 4-[3-(triphenylen-2-yl)phenyl]dibene Thiophene compounds such as dithiophene (abbreviation: mDBTPTp-II), furan compounds, A fluorene compound, a triphenylene compound, a phenanthrene compound, etc. can be used. Among the compounds mentioned above, those with pyrrole skeleton, furan skeleton, thiophene skeleton, aromatic amine skeleton, Compounds having such a skeleton are preferred because they are stable and highly reliable. The compound has a high hole transporting property and also contributes to a reduction in driving voltage.

[0163] <Hole transport layer> The hole transport layer 112 is a layer containing a hole transport material. The hole transporting layer 112 can be formed by the hole injection layer 111. The HOM of the hole injection layer 111 has a function of transporting the injected holes to the light-emitting layer 130. O(Highest Occupied Molecular Orbital) It is preferable that the HOMO level is the same as or close to the HOMO level (also called occupied orbital level).

[0164] Also, 1×10 -6 cm 2It is preferable that the material has a hole mobility of 1 / Vs or more. However, other substances may be used as long as they have a higher hole transporting property than electron transporting property. The layer containing a substance with a high hole transporting property may be a single layer or a double layer of the above substance. More than one layer may be stacked.

[0165] ≪Electron transport layer≫ The electron transport layer 118 is connected to the other of the pair of electrodes (electrode 101 or electrode 102) via the electron injection layer 119. The electron transport material has the function of transporting electrons injected from the electrode 102 to the light-emitting layer 130. As the material, a material with higher electron transportability than holes can be used, and the -6 cm 2 It is preferable that the material has an electron mobility of 1 / Vs or more. As materials (materials with electron transport properties), π-electron deficient materials such as nitrogen-containing heteroaromatic compounds are Heteroaromatics and metal complexes can be used. The pyridine derivatives, bipyridine derivatives, and pyrimidine derivatives listed as electron transport materials that can Derivatives, triazine derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, phenazine Intramolecular derivatives, triazole derivatives, benzimidazole derivatives, oxadiazole Derivatives include those with a heteroaromatic skeleton containing two or more nitrogen atoms and 1 to 20 carbon atoms. In particular, compounds having a pyrimidine skeleton and a triazine skeleton are preferred. Also, 1×10 -6 cm 2 It is preferable that the material has an electron mobility of 1 / Vs or more. It is to be noted that, as long as a substance has a higher electron transporting property than a hole transporting property, a substance other than those mentioned above can be used as the electron transporting layer. The electron transport layer 118 may be formed not only as a single layer but also as a layer made of the above-mentioned material. Two or more layers may be laminated.

[0166] Further, metal complexes having heterocycles are also exemplified, for example, quinoline ligands, benzoquinoline Metal complexes with oxazole, thiazole, or thiazole ligands are also suitable. Specifically, for example, tris(8-quinolinolato)aluminum(III) (abbreviation: A lq), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Al mq3), bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation :BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)a Aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Metal complexes having a quinoline skeleton or a benzoquinoline skeleton, such as Znq, In addition, bis[2-(2-benzoxazolyl)phenolato]zinc(II)( Abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phenolato]zinc(II) ( Metal complexes with oxazole or thiazole ligands, such as ZnBTZ Also, the following can be used.

[0167] In addition, a layer for controlling the movement of electron carriers is provided between the electron transport layer 118 and the light emitting layer 130. This is a method of adding a material with high electron transporting properties to a material with high electron trapping properties. A layer containing a small amount of Such a configuration allows the electron transporting property of the electron transporting material to be properly adjusted. Problems that occur when the hole transporting property of the hole transporting material is significantly higher than that of the hole transporting material (e.g., shortened device life). It is highly effective in suppressing the following:

[0168] ≪Electron injection layer≫ The electron injection layer 119 promotes electron injection by reducing the electron injection barrier from the electrode 102. For example, Group 1 metals, Group 2 metals, or their oxides and halides In addition, the electron transport material and the corresponding electron transport material can be used. A composite material of a material exhibiting electron donating properties can also be used. Examples include Group 1 metals, Group 2 metals, and oxides thereof. are lithium fluoride (LiF), sodium fluoride (NaF), and cesium fluoride (CsF ), calcium fluoride (CaF2), lithium oxide (LiO x ) and other alkaline gold Metals, alkaline earth metals, or compounds thereof can be used. A rare earth metal compound such as erbium (ErF3) can be used. An electride may be used for 119. The electride may be, for example, calcium. Examples include a material in which electrons are highly concentrated in a mixed oxide of aluminum and silicon. The injection layer 119 may be made of a material that can be used in the electron transport layer 118 .

[0169] The electron injection layer 119 may contain a composite material formed by mixing an organic compound and an electron donor (donor). Such composite materials may be formed by electron donors giving electrons to organic compounds. In this case, the organic compound is It is preferable that the material is excellent in transporting the generated electrons. Specifically, for example, the above-mentioned The material constituting the electron transport layer 118 (metal complex, heteroaromatic compound, etc.) can be used. The electron donor may be any substance that exhibits electron donating properties to organic compounds. For the metal, alkali metals, alkaline earth metals and rare earth metals are preferred, and lithium, sodium , cesium, magnesium, calcium, erbium, ytterbium, etc. In addition, alkali metal oxides and alkaline earth metal oxides are preferred, and lithium oxide, calcium oxide, Examples of oxides include sodium oxide and barium oxide. Lewis oxides such as magnesium oxide are also included. A base can also be used. In addition, organic compounds such as tetrathiafulvalene (TTF) can be used. You can also use objects.

[0170] The above-mentioned light-emitting layer, hole-injection layer, hole-transport layer, electron-transport layer, and electron-injection layer are These methods include vapor deposition (including vacuum deposition), inkjet printing, coating, and gravure printing. The light-emitting layer, the hole-injecting layer, the hole-transporting layer, the electron In addition to the materials mentioned above, inorganic compounds such as quantum dots and high molecular weight compounds can be used for the transport layer and electron injection layer. A polymer compound (oligomer, dendrimer, polymer, etc.) may also be used.

[0171] ≪Quantum dots≫ Quantum dots are semiconductor nanocrystals with sizes ranging from several nanometers to several tens of nanometers, and are 1×10 3 pieces~1× 10 6 Quantum dots are composed of about 100 atoms. Therefore, even quantum dots made of the same material have different emission wavelengths depending on their size. Therefore, by changing the size of the quantum dots used, the emission wavelength can be easily adjusted. can be changed.

[0172] In addition, quantum dots have a narrow peak width in the emission spectrum, which allows for emission of light with good color purity. Furthermore, the theoretical internal quantum efficiency of quantum dots is said to be nearly 100%. This is significantly more than 25% of organic compounds that exhibit fluorescence, and 25% of organic compounds that exhibit phosphorescence. This means that quantum dots can be used as light-emitting materials. This allows for the production of light-emitting devices with high luminous efficiency. Since the inherent stability is also excellent, a light emitting device that is preferable in terms of life can be obtained. This can be done.

[0173] The materials that make up quantum dots include elements from Group 14, Group 15, Group 16, and complexes. Compounds consisting of several Group 14 elements, compounds consisting of elements belonging to Groups 4 to 14 and Group 16 elements compounds of Group 2 elements and Group 16 elements; compounds of Group 13 elements and Group 15 elements; Compounds of Group 13 elements and Group 17 elements, compounds of Group 14 elements and Group 15 elements, Compounds of group 1 and group 17 elements, iron oxides, titanium oxides, chalcogenide spinels Examples include semiconductor clusters.

[0174] Specifically, cadmium selenide, cadmium sulfide, cadmium telluride, and sulfur selenide Lead, zinc oxide, zinc sulfide, zinc telluride, mercury sulfide, mercury selenide, mercury telluride, arsenide Indium, indium phosphide, gallium arsenide, gallium phosphide, indium nitride, nitride Gallium, indium antimonide, gallium antimonide, aluminum phosphide, arsenide Aluminum, aluminum antimonide, lead selenide, lead telluride, lead sulfide, selenide Indium, indium telluride, indium sulfide, gallium selenide, arsenic sulfide, selenium arsenic nitride, arsenic telluride, antimony sulfide, antimony selenide, antimony telluride, Bismuth sulfide, bismuth selenide, bismuth telluride, silicon, silicon carbide, germanium Aluminum, tin, selenium, tellurium, boron, carbon, phosphorus, boron nitride, boron phosphide, boron arsenide , aluminum nitride, aluminum sulfide, barium sulfide, barium selenide, barium telluride Sulfur dioxide, calcium sulfide, calcium selenide, calcium telluride, beryllium sulfide, Beryllium selenide, beryllium telluride, magnesium sulfide, magnesium selenide, Germanium sulfide, germanium selenide, germanium telluride, tin sulfide, tin selenide , tin telluride, lead oxide, copper fluoride, copper chloride, copper bromide, copper iodide, copper oxide, copper selenide, acid Nickel oxide, cobalt oxide, cobalt sulfide, iron oxide, iron sulfide, manganese oxide, molyb sulfide vanadium oxide, tungsten oxide, tantalum oxide, titanium oxide, zirconium oxide Aluminum, silicon nitride, germanium nitride, aluminum oxide, barium titanate, selenium and zinc Compounds of lead and cadmium, compounds of indium, arsenic and phosphorus, compounds of cadmium, selenium and sulfur Compounds of cadmium, selenium and tellurium, compounds of indium, gallium and arsenic , compounds of indium, gallium and selenium, compounds of indium, selenium and sulfur, compounds of copper and indium Examples of the compounds include indium and sulfur compounds, and combinations thereof. In addition, alloy quantum dots, whose compositions are expressed in any ratio, may be used. For example, alloy quantum dots of cadmium, selenium, and sulfur can be obtained by changing the ratio of the elements. This is one of the effective methods to obtain blue light emission, because the emission wavelength can be changed by It is one.

[0175] Quantum dot structures include core type, core-shell type, and core-multishell type. Either of these can be used, but it is also possible to cover the core with another inorganic compound with a wider band gap. By forming a shell of material, defects and dangling bonds on the nanocrystal surface can be eliminated. This significantly improves the quantum efficiency of light emission, It is preferable to use core-shell or core-multishell quantum dots. Examples of materials include zinc sulfide and zinc oxide.

[0176] In addition, quantum dots have a high proportion of surface atoms, making them highly reactive and prone to aggregation. Therefore, a protective agent or a protective group is attached to the surface of the quantum dots. It is preferable that the protecting agent is attached or the protecting group is provided. It can prevent aggregation and increase solubility in solvents. It can also reduce reactivity and improve electrical conductivity. It is also possible to improve stability. Examples of protecting agents (or protecting groups) include polio Polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene Polyoxyethylene alkyl ethers such as ethylene oleyl ether, tripropyl phosphite phosphine, tributylphosphine, trihexylphosphine, trioctylphosphine, etc. Trialkylphosphines, polyoxyethylene n-octylphenyl ether, polyoxyethylene Polyoxyethylene alkylphenyl ethers such as oxyethylene n-nonylphenyl ether esters, tri(n-hexyl)amine, tri(n-octyl)amine, tri(n-decyl)amine ) Tertiary amines such as amine, tripropylphosphine oxide, tributylphosphine oxide, trihexylphosphine oxide, trioctylphosphine oxide, tridecylphosphine oxide Organic phosphorus compounds such as silylphosphine oxide, polyethylene glycol dilaurate, polyethylene glycol diesters such as polyethylene glycol distearate, Organic nitrogen compounds such as nitrogen-containing aromatic compounds such as pyridine, lutidine, collidine, and quinolines , hexylamine, octylamine, decylamine, dodecylamine, tetradecylamine aminoalkanes such as dibutylsulfone, hexadecylamine, and octadecylamine; dialkyl sulfides such as dimethyl sulfoxide and dibutyl sulfoxide; organic sulfur compounds such as alkyl sulfoxides, sulfur-containing aromatic compounds such as thiophene, palmitoyl Higher fatty acids such as acetic acid, stearic acid, and oleic acid, alcohols, sorbitan fatty acid esters esters, fatty acid modified polyesters, tertiary amine modified polyurethanes, polyethylene terephthalate Examples include amines.

[0177] As quantum dots become smaller, their band gaps become larger, so they can emit the desired wavelengths. The size of the crystal is adjusted accordingly to obtain long-range light. As a result, the emission of quantum dots shifts to the blue side, i.e., to the higher energy side. By changing the size of the filter, wavelengths in the ultraviolet, visible, and infrared regions of the spectrum can be obtained. The size (diameter) of quantum dots can be adjusted over a range of wavelengths. The range of 0.5 nm to 20 nm, preferably 1 nm to 10 nm, is usually used. The narrower the size distribution of quantum dots, the narrower the emission spectrum. The quantum dots can be formed in any shape, and can have excellent color purity. The quantum dots may be spherical, rod-shaped, disc-shaped, or have other shapes. Since the rods have the function of emitting directional light, quantum rods can be used as light-emitting materials. This makes it possible to obtain a light emitting device with better external quantum efficiency.

[0178] In most cases, organic EL devices are made by dispersing a light-emitting material in a host material. The host material is more than just a light-emitting material; it also has a high luminous efficiency. The material must have a singlet or triplet excited energy level. In particular, when a blue phosphorescent material is used as the light-emitting material, triplet excitation energy of A host material with a high level and excellent lifetime is required, and its development is extremely difficult. Here, the quantum dots are used to form a light-emitting layer without using a host material. Therefore, in this respect, it is a preferable light-emitting element from the viewpoint of life span. When the light-emitting layer is formed only from quantum dots, the quantum dots are core- A shell structure (including a core-multishell structure) is preferred.

[0179] When quantum dots are used as the light-emitting material of the light-emitting layer, the thickness of the light-emitting layer is 3 nm to 100 nm. m, preferably 10 nm to 100 nm, and the content of quantum dots in the light-emitting layer is 1 to 1 However, it is preferable to form the light-emitting layer only from quantum dots. When forming a light-emitting layer in which the quantum dots are dispersed in a host as a light-emitting material, the host material Alternatively, the host material and the quantum dots are dissolved or dispersed in a suitable liquid medium. Disperse and apply wet processes (spin coating, casting, die coating, blade coating) Coating method, roll coating method, inkjet method, printing method, spray coating method, curtain coating The phosphorescent material may be formed by a method such as the ion beam splitting method or the Langmuir-Blodgett method. For the light-emitting layer using the above, in addition to the wet process, a vacuum deposition method can also be suitably used. This can be done.

[0180] Examples of liquid media used in wet processes include methyl ethyl ketone, cyclohexane, and the like. Ketones such as xanone, fatty acid esters such as ethyl acetate, halogens such as dichlorobenzene aromatic hydrocarbons, toluene, xylene, mesitylene, cyclohexylbenzene, etc. Hydrocarbons, aliphatic hydrocarbons such as cyclohexane, decalin, and dodecane, dimethylformamide Organic solvents such as dimethyl amide (DMF) and dimethyl sulfoxide (DMSO) can be used. Cut.

[0181] <Pair of electrodes> The electrode 101 and the electrode 102 function as an anode or a cathode of the light-emitting element. The electrode 101 and the electrode 102 may be made of a metal, an alloy, a conductive compound, or a mixture or laminate thereof. It can be formed using, for example.

[0182] One of the electrodes 101 and 102 is made of a conductive material that has a function of reflecting light. The conductive material is preferably aluminum (Al) or a compound containing Al. Examples of alloys containing Al include Al and L (L is titanium (Ti), neodymium (Ne), etc. (representing one or more of Nd, Ni, and La) Examples of suitable alloys include alloys containing Al and Ti, or alloys containing Al, Ni and La. Aluminum has low resistance and high light reflectivity. Since aluminum is abundant and inexpensive, the cost of manufacturing a light-emitting element using aluminum is reduced. In addition, silver (Ag) or Ag and N (N) can be used in combination with yttrium ( Y), Nd, magnesium (Mg), ytterbium (Yb), Al, Ti, gallium ( Ga), zinc (Zn), indium (In), tungsten (W), manganese (Mn), Tin (Sn), iron (Fe), Ni, copper (Cu), palladium (Pd), iridium (Ir ), or an alloy containing gold (Au), etc. Examples of alloys containing silver include alloys containing silver, palladium, and copper, alloys containing silver and copper, and alloys containing silver and magnesium. Alloys containing nesium, alloys containing silver and nickel, alloys containing silver and gold, silver and ytterbium Other examples include alloys containing W, chromium (Cr), molybdenum (Mo), Cu, A transition metal such as Ti can be used.

[0183] The light emitted from the light-emitting layer is emitted through one or both of the electrodes 101 and 102. Therefore, at least one of the electrodes 101 and 102 is transparent to light. It is preferable that the conductive material is formed of a conductive material having a permeability function. The transmittance of visible light is 40% or more and 100% or less, preferably 60% or more and 100% or less, or The resistivity is 1×10 -2 Examples include conductive materials with a resistance of Ω·cm or less.

[0184] The electrodes 101 and 102 have a function of transmitting light and a function of reflecting light. The conductive material may be formed of a conductive material having a visible light reflectance of 20 or less. % or more and 80% or less, preferably 40% or more and 70% or less, and the resistivity is 1×10 -2 Conductive materials with a resistance of Ω·cm or less include metals, alloys, and conductive materials. The layer can be formed by using one or more of the following compounds. Indium Tin Oxide (ITO), silicon or silicon oxide Indium tin oxide (ITSO), indium oxide-zinc oxide (Indi Indium tin oxide containing titanium, indium tin oxide, Metals such as indium oxide containing titanium oxide, tungsten oxide, and zinc oxide Oxides can be used. In addition, the thickness of the oxide is preferably within a range of 1 nm to 30 nm. A metal thin film having a thickness of 1 μm or less can be used. Examples of metals include Ag, Alloys such as Ag and Al, Ag and Mg, Ag and Au, and Ag and Yb can be used.

[0185] In this specification and the like, a material having a function of transmitting light refers to a material having a function of transmitting visible light. Any material having the above and having electrical conductivity may be used, and examples thereof include ITO. In addition to oxide conductors, oxide semiconductors or organic conductors containing organic materials are also included. The organic conductor may be, for example, a mixture of an organic compound and an electron donor. Examples of such materials include composite materials, and composite materials made by mixing organic compounds and electron acceptors. Alternatively, inorganic carbon materials such as graphene may be used. The ratio is preferably 1 x 10 5 Ω·cm or less, more preferably 1×10 4 Ω cm The following is the result.

[0186] In addition, by laminating a plurality of the above materials, one or both of the electrodes 101 and 102 can be formed. may form both.

[0187] In order to improve the light extraction efficiency, the electrode is in contact with the light-transmitting electrode. A material having a higher refractive index than the electrode may be used. Any material that has the function of providing the desired electrical conductivity may be used. For example, in addition to the oxide conductors described above, oxide semiconductors and organic materials can be used. The organic material may be, for example, a light-emitting layer, a hole-injection layer, a hole-transport layer, an electron-transport layer, or an electron The materials exemplified for the electron injection layer are also usable. Inorganic carbon materials and metals that are light-transmitting are also usable. A thin film can also be used, and multiple layers of several nanometers to several tens of nanometers may be stacked.

[0188] When the electrode 101 or the electrode 102 functions as a cathode, the work function is small. (3.8 eV or less) materials. For example, materials in Group 1 or 2 of the Periodic Table of Elements. Elements belonging to the group (alkali metals such as lithium, sodium, and cesium, calcium, strontium, etc.) Alkaline earth metals such as rontium, magnesium, etc.), alloys containing these elements (e.g., Rare earth metals such as Ag and Mg, Al and Li), europium (Eu), Yb, etc. An alloy containing a metal, such as an alloy containing aluminum or silver, can be used.

[0189] Furthermore, when the electrode 101 or the electrode 102 is used as an anode, a material having a large work function (4. It is preferable to use a material having a refractive index of 0 eV or more.

[0190] The electrodes 101 and 102 are made of a conductive material that reflects light and a light-transmitting material. In this case, the electrode 101 and the electrode 102 may be laminated with a conductive material having a permeability function. O2 can resonate light of a desired wavelength from each light-emitting layer and intensify the light of the desired wavelength. This is preferable because it has the function of adjusting the optical distance so that the optical path can be adjusted.

[0191] The electrode 101 and the electrode 102 can be formed by a sputtering method, a vapor deposition method, a printing method, or a coating method. , MBE (Molecular Beam Epitaxy) method, CVD method, pulse laser The deposition method, ALD (Atomic Layer Deposition) method, etc. are used appropriately. It is possible.

[0192] <Substrate> Furthermore, the light-emitting element according to one embodiment of the present invention may be formed on a substrate made of glass, plastic, or the like. As for the order of fabrication on the substrate, the layers may be stacked in order from the electrode 101 side. They may be stacked in order from the pole 102 side.

[0193] The substrate on which the light-emitting element according to one embodiment of the present invention can be formed is, for example, glass or quartz. Alternatively, a flexible substrate may be used. The substrate is a flexible substrate, such as polycarbonate. Examples of suitable substrates include plastic substrates made of vinyl acetate and polyarylate. Inorganic vapor deposition films can also be used. Any other material may be used as long as it functions as a support in the development. Anything that has the function of protecting the optical element and the optical device may be used.

[0194] For example, in the present invention, a light emitting element can be formed using various substrates. The type of substrate is not particularly limited. An example of the substrate is a semiconductor substrate (e.g., a single crystal substrate or silicon substrate), SOI substrate, glass substrate, quartz substrate, plastic substrate, metal Substrate, stainless steel substrate, substrate with stainless steel foil, tungsten substrate, tungsten foil substrate, flexible substrate, laminated film, fibrous Examples of glass substrates include paper or substrate films containing barium phosphate. Examples include borosilicate glass, aluminoborosilicate glass, and soda-lime glass. Examples of the functional substrate, laminate film, base film, etc. are as follows: For example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), Representative examples include polyethersulfone (PES) and polytetrafluoroethylene (PTFE). For example, there is a plastic material such as acrylic resin. Examples include polypropylene, polyester, polyvinyl fluoride, or polyvinyl chloride. Examples include polyamide, polyimide, aramid, epoxy, and inorganic. Examples include metallized films and papers.

[0195] Alternatively, a flexible substrate may be used as the substrate, and the light emitting element may be formed directly on the flexible substrate. Alternatively, a release layer may be provided between the substrate and the light-emitting element. After a part or all of a device is completed, it is separated from the substrate and used to transfer it to another substrate. In this case, the light-emitting element can be transferred onto a substrate having poor heat resistance or a flexible substrate. The peeling layer may have a laminated structure of inorganic films, such as a tungsten film and a silicon oxide film. or a structure in which a resin film such as polyimide is formed on a substrate, etc., can be used.

[0196] That is, a light emitting element is formed using a certain substrate, and then the light emitting element is transferred to another substrate. The light emitting element may be disposed on another substrate. In addition to the substrates mentioned above, cellophane substrates, stone substrates, wood substrates, fabric substrates (natural fibers (silk, cotton, Hemp), synthetic fibers (nylon, polyurethane, polyester) or regenerated fibers (acetate (including cellulose, cupro, rayon, recycled polyester, etc.), leather substrate, rubber substrate, etc. By using these substrates, it is possible to produce light emitting elements that are durable and highly heat resistant. The light emitting element may be a small, lightweight, or thin light emitting element.

[0197] Furthermore, for example, a field effect transistor (FET) is formed on the above-mentioned substrate, and the FET and The light emitting element 150 may be fabricated on the electrically connected electrodes. In this way, an active matrix display device that controls the driving of the light emitting element 150 can be fabricated.

[0198] The components of a solar cell, which is an example of an electronic device according to one embodiment of the present invention, will be described below. Do the following.

[0199] The materials that can be used for the light-emitting element described above can be used for the solar cell. The carrier transport layer of the pond is made of the hole transport material and electron transport material described above, and the photovoltaic layer is made of The hole transport material, electron transport material, light emitting material, silicon, and CH3NH3PbI Perovskite crystals such as those shown in Figure 3 can be used. The above-mentioned materials that can be used for the light-emitting element can also be used.

[0200] As described above, the structure shown in this embodiment mode can be used in appropriate combination with other embodiment modes. Cut.

[0201] (Embodiment 2) 35A shows a light-emitting element according to one embodiment of the present invention. 10, has a cathode 311 and an EL layer 312 containing an organic compound sandwiched therebetween.

[0202] The EL layer 312 has a light-emitting layer 314 and a first layer 313. The light-emitting layer 314 is a light-emitting element. The light emitting device mainly emits light from the light emitting layer 314. In addition, the first layer 313 is a layer containing an organic compound and an inorganic compound.

[0203] The organic compound in the first layer 313 is preferably an organic compound having an electron transporting property. The inorganic compounds include alkali metal fluorides or alkaline earth metal fluorides. Preferably, it is a layer.

[0204] Here, the refractive index of organic compounds with good carrier transport properties used in organic electronic devices is 1 The refractive index of alkali metal fluorides or alkaline earth metal fluorides is about 0.7. Since the pH is about 1.35, it is possible to distinguish organic compounds from alkali metal fluorides or alkaline earth metal fluorides. The first layer 313 containing fluoride of an organic metal is made of a material used in ordinary light emitting devices. The layer may have a lower refractive index compared to the layer.

[0205] FIG. 36 is a graph showing the refractive index of a mixed film made of BPhen and lithium fluoride. The horizontal axis of the graph is the concentration of BPhen. The plot on the right is the refraction of BPhen itself. The leftmost plot represents the refractive index of lithium fluoride itself. Although there are differences, the refractive index of the film varies depending on the content of lithium fluoride and BPhen. As mentioned above, the fluorides of alkali metals or alkaline earth metals change The first layer 313 containing the above has a refractive index lower than that of a layer using a material used in a normal light-emitting device. It can be seen that this is the layer with a low rate.

[0206] In this manner, according to one embodiment of the present invention, a layer having a low refractive index is provided between the light-emitting layer and the cathode. By providing a layer with a low refractive index inside the light-emitting element, As described above, the light-emitting efficiency of the light-emitting element can be improved. is thought to be due to the suppression of thin film modes and surface plasmon-polariton modes. Therefore, as in one embodiment of the present invention, the first layer 313 having a low refractive index is provided in the light-emitting element. As a result, the light-emitting element of one embodiment of the present invention can have high emission efficiency. .

[0207] The first layer 313 may be formed of an alkali metal fluoride or an alkaline earth metal fluoride. If the fluoride content is greater than 0 vol%, the first layer 313 is composed of only organic compounds. Since the refractive index is lower than when the light emitting element is made of a thin film, the light emitting efficiency of the light emitting element is improved. As mentioned above, the refractive index increases as the content of the fluoride in the first layer 313 increases. The light-emitting efficiency of the light-emitting element is improved because the efficiency of the light-emitting element is reduced. It was found that the efficiency drops significantly when the lithium fluoride content exceeds 95 vol%. (See FIG. 37). Therefore, the alkali metal fluoride or The alkaline earth metal fluoride content is preferably less than 95 vol %.

[0208] The driving voltage is determined by the amount of the alkali metal fluoride or alkali metal in the first layer 313. In the case of a light-emitting element in which the content of earth metal fluorides is 0 vol% or more and less than 50 vol%, the fluorides It is also noted that as the fluoride content increases, the amount of current at the same voltage tends to decrease. In other words, in this concentration range, the driving voltage of the light-emitting element is However, surprisingly, when the fluoride content is 50 vol% or more, the As the fluoride content increases, the amount of current at the same voltage tends to increase. As a result of the investigations conducted by the present inventors, it was found that the fluoride content is 50 vol% or more. In this region, the driving voltage also decreases. The content of fluorides of alkaline earth metals is preferably 50 vol% or more. stomach.

[0209] As will be described later, the content of lithium fluoride of 50 vol % in the first layer 313 At this concentration, alkali metal fluorides or alkaline earth metal fluorides begin to crystallize. That is, the decrease in the driving voltage accompanying the increase in the amount of current is due to the alkali metal in the first layer 313. This is related to the increase in the content of fluorides of metals or alkaline earth metals and their crystallization. It is considered that the aluminum contained in the first layer 313 at a content of 50 vol % or more The potassium metal fluoride or alkaline earth metal fluoride is in a microcrystalline state in the layer. It is also known to exist in

[0210] As described above, in one embodiment of the present invention, the alkali metal fluoride or The alkaline earth metal fluoride content must be between 50 vol% and 95 vol%. In addition, a range of 60 vol % to 80 vol % is more preferable since it provides a better driving voltage. The best properties are obtained at 75 vol%, so the range is 70 vol% to 80 vol%. It is more preferable that the temperature is lower than the reference temperature.

[0211] Thus, in one embodiment of the present invention, the alkali metal fluoride or The content of alkaline earth metal fluoride is preferably 50 vol% or more. However, in the materials conventionally used as the electron injection layer and the electron transport layer, As shown above, the fluoride of an alkali metal or an alkaline earth metal is contained in a large amount. This is because the fluorides of alkali metals or alkaline earth metals are This is thought to be because fluorides of metals are insulating, and so it was assumed that the characteristics would deteriorate. In fact, in the region where the fluoride content is less than 50 vol%, the driving voltage deteriorates as expected. However, in this situation, In one aspect of the present invention, the driving voltage characteristics are improved in the region of 50 vol % or more, and the driving voltage The light-emitting device is excellent in that it has high efficiency and is provided with a low refractive index layer. It can be said to be groundbreaking.

[0212] The organic compound used for the first layer 313 is an organic compound having an electron transporting property. It is preferable that the first layer 313 is provided between the light-emitting layer 314 and the cathode 311. Preferably, the first layer 313 can also function as a part of the electron transport layer. , an electron-transporting organic compound and an alkali metal fluoride or an alkaline earth metal fluoride and the content of alkali metal fluorides or alkaline earth metal fluorides is 50V The first layer containing fluoride at vol % or more contains microcrystals of the fluoride and has high electron transport properties. The use of such a first layer 313 as a part or the whole of the electron transport layer reduces the driving voltage. This is a preferable configuration because it is expected that the temperature will be reduced. Since it shows good properties even when in contact with 311, it can also serve as an electron injection layer. The first layer 313 also serves as an electron transport layer, thereby reducing the number of layers constituting the light-emitting element. This configuration is advantageous in terms of cost.

[0213] The organic compound having electron transport properties is preferably a π-electron deficient heteroaromatic compound. Among them, organic compounds having a bipyridine skeleton such as a phenanthroline skeleton are preferred. Specifically, bathophenanthroline (abbreviated as BPhen) and 2,9-bis(naphthalene) NBPh en) is preferred, but NBPhen, which has a particularly high glass transition temperature (Tg) and high heat resistance, is preferred. is preferred.

[0214] Here, the portion corresponding to the first layer 313 in the light-emitting element having the structure of one embodiment of the present invention Using a Hitachi High-Technologies Corporation scanning transmission electron microscope (HD-2700), X-ray analysis (EDX:Energy Dispersive X-ray spectro The results of the EDX analysis are shown in Figure 39. The EDX measurement was performed at each point in the analysis area of ​​the sample. Electron beam irradiation is performed, and the energy and number of characteristic X-rays generated by the sample are measured. In this embodiment, the EDX spectrum for each point is obtained. The elements were identified from the peak energy, and the peak intensity ratio was calculated using the software attached to the HD-2700. The element concentration ratios were calculated from the data.

[0215] The first layer 313 in the light-emitting element used as a sample was made of BPh represented by the following structural formula: The film contains en and lithium fluoride, and the lithium fluoride content is 75 vol%. Ta.

[0216] [ka]

[0217] Table 11 shows the abundance ratio of each atom calculated from the spectral peaks in FIG.

[0218] [Table 11]

[0219] From Figure 39 and Table 11, the number of fluorine atoms in the layer is clearly greater than the number of nitrogen atoms. The intensity of the detected nitrogen was more than three times higher. In addition, the film contained lithium fluoride. This can be confirmed by TOF-SIMS, TEM-EELS, XPS, etc. The film and light-emitting device of the embodiment show characteristic measurement results by the above-mentioned analysis. Some organic compounds contain a lot of fluorine, but the existence of such organic compounds This can be confirmed by TOF-SIMS, TEM-EELS, and XPS. It is possible to separate this from the results of the present invention.

[0220] Next, the results of selected area electron diffraction analysis of the light-emitting element of one embodiment of the present invention will be shown. The diagram shown in FIG. 40 is a cross-sectional transmission electron microscope (TEM) photograph of a light-emitting element according to one embodiment of the present invention. The four circles shown in the figure are the areas where selected area electron diffraction analysis was performed. TEM observation and selected area electron diffraction analysis were performed using Hitachi High-Technologies Corporation. This was performed using -9000NAR.

[0221] The results of the selected area electron diffraction analysis of each measurement point are shown in the bottom of Figure 40, and the TEM images in the top of Figure 40 The first layer 313 corresponds to the photo with the same reference numeral in the photograph. The first layer 313 is a layer made of lithium fluoride, and the content of lithium fluoride in the first layer 313 is 75 vol% samples were used.

[0222] As can be seen from the upper diagram of FIG. 40, the measurement points including the first layer 313 are *1 and *2, and *3 and *4 are It can be seen that the measurement points do not include the first layer 313, but only *1 and *2 in the figure below show phosphorus. The pattern was composed of bright particles in a granular pattern. This pattern was due to the presence of crystals with different orientations in the layer. This suggests that there are some. However, there are no such things in *3 and *4. The halo pattern indicating the rufus and the spots originating from the aluminum used as the cathode are Thus, it was found that there is a high probability that the first layer 313 contains microcrystals. It was.

[0223] In addition, a similar analysis was performed on a light-emitting device using calcium fluoride instead of lithium fluoride. The first layer 313 in the TEM photograph in FIG. 41 is composed of BPhen and calcium fluoride. The first layer 313 is a layer made of calcium fluoride, and the content of calcium fluoride in the first layer 313 is 75 vol %. The three circles shown in the TEM photograph are the areas where the selected area electron diffraction analysis was performed. This is the location.

[0224] From the upper diagram of FIG. 41, the measurement points including the first layer 313 are *1 and *2, and *3 is the first It can be seen that the measurement points do not include layer 313, but only in the figures *1 and *2 below, there is a ring-shaped Particulate bright spots were observed in the pattern. This pattern is due to the existence of crystals with different orientations in the layer. This suggests that these are present. Only a low pattern was observed. Thus, it is likely that the first layer 313 contains microcrystals. was found to be highly

[0225] Next, when this sample was observed under high magnification TEM, lattice fringes were confirmed (Figure 42 In Figure 42, lattice fringes indicating crystallization are observed, with a size of about 10 nm. The orientation of the lattice lines was random. From this result, it is clear that the BPhen and calcium fluoride It can be seen that the first layer 313 is made up of microcrystals with random crystal orientations. .

[0226] Here, the mixed film of BPhen and lithium fluoride was analyzed by Fourier transform infrared spectroscopy (FT- IR:Fourier Transform Infrared Spectrosco Attenuated Total Reflection (ATR) measurement The results of FT-IR measurements (ATR method) are shown in Figures 43(A) to 43(C). - Nicolet iS50 Analytical Instrument from Fisher Scientific The measurement sample was a vapor-deposited film of about 50 nm formed on a quartz substrate. Used.

[0227] In this measurement, a mixed film of BPhen and lithium fluoride was measured, but multiple films with different mixture ratios were also measured. Several samples were prepared. Figure 43(B) shows the 1300 cm -1 ~170 0cm -1 The range of Fig. 43(C) is 400cm -1 ~800cm -1 Expanding the scope of This is a graph showing the results. -1 ~1700cm -1 Absorption in the range is mainly BP This absorption is due to hen, and is at 650cm -1 with a peak at 500 cm -1 ~70 0cm -1 The absorption in the range is mainly due to the vibration of lithium fluoride.

[0228] 1400cm -1 ~1700cm -1 The absorption of BPhen is due to the inclusion of BPhen. There was a tendency for the size to increase as the prevalence increased. -1 ~ 700cm -1 The absorption due to lithium fluoride is There was almost no change up to about 1%, but above that there was a tendency for it to increase.

[0229] Figure 44 shows 1491cm -1 and 644cm -1 The relationship between the BPhen ratio and absorbance is The plotted results are shown in Figure 44. -1 BPhen with a peak at The absorption due to BPhen increases with increasing concentration, whereas the absorption due to BPhen increases with increasing concentration. - 1 The absorption intensity with a peak at 50 volts does not increase at low lithium fluoride concentrations. It is clear that the temperature starts to rise from around 1%. -1 A peak at The IR absorption of lithium fluoride is due to the longitudinal optical lattice vibration of the lithium fluoride crystal. Lithium fluoride begins to crystallize when its content exceeds 50 vol%, and the crystallization progresses with increasing concentration. It was found that many parts were converted.

[0230] That is, taking into consideration the results of the above-mentioned selected area electron diffraction analysis, the inclusion of lithium fluoride The first layer 313 having a content of 50 vol % or more is a layer having lithium fluoride microcrystals. Furthermore, these results and the results of Figure 38 (with the lithium fluoride content) When the content is increased, the current amount decreases and the driving voltage increases, but when the content exceeds 50 vol%, the current amount increases. As the first layer 313 crystallizes, the driving voltage of the light emitting element decreases. It is thought that this will lead to a decline.

[0231] In this way, organic compounds and alkali metal fluorides or alkaline earth metal fluorides The light-emitting element having the first layer 313 containing The inclusion of metal fluoride or alkaline earth metal fluoride microcrystals reduces the driving voltage. A light-emitting element with low emission can be obtained.

[0232] In addition, alkali metal fluorides such as alkali metal fluorides or alkaline earth metal fluorides Alternatively, since alkaline earth metal salts are inexpensive, an electron transport layer containing more than half of these metal salts may be used. The light emitting element used can be an inexpensive light emitting element, which is advantageous in terms of cost.

[0233] The important point of the present invention is that even if the first layer 313 as described above is provided in the element, the above-mentioned generation The advantage is that it can be formed without significantly adversely affecting the characteristics of the optical element.

[0234] Normally, it has a low refractive index and high carrier transport property or signal strength when used in a light-emitting device. There is a trade-off between the carrier transport and reliability of organic compounds. The reliability is largely due to the presence of unsaturated bonds, and organic compounds with many unsaturated bonds This is because the refractive index tends to be high.

[0235] The refractive index of a material is given by μ being the magnetic permeability of the material, ε being the dielectric constant of the material, μ0 being the magnetic permeability of a vacuum, and ε0 When the dielectric constant of a vacuum is taken as (με / μ o ε o ) the larger the non-dielectric constant, the In organic compounds, the more unsaturated bonds there are, the higher the refractive index becomes. The dielectric constant tends to be large because of the ease of charge transfer in the The presence of saturated bonds causes the refractive index to increase.

[0236] Here, organic compounds that exhibit high carrier transport properties are unsaturated hydrocarbons with a wide π-conjugated system. The organic compound that can provide high reliability when used as a material for a light-emitting device is an unsaturated It is known to be an unsaturated hydrocarbon with a rigid structure due to bonds and a high Tg. Therefore, in order to form a layer with a low refractive index, an organic compound with fewer unsaturated bonds is selected. If the organic compound is selected, the driving voltage will increase due to the poor carrier transport property of the organic compound. However, the lack of a rigid structure can lead to a decrease in reliability. A layer with a low refractive index can be formed in a light-emitting device without significantly sacrificing the device characteristics. It was very difficult to form.

[0237] In one embodiment of the present invention, a fluoride of an alkali metal and a fluoride of an alkali metal are used in a high content that has not been used in the past. An organic compound containing an alkaline earth metal fluoride is used as the first layer 313 . This has the effect of improving the light-emitting efficiency, reducing the driving voltage, and enabling low-cost production. can be obtained.

[0238] Next, materials that can be used for the first layer 313 will be specifically described. As shown, the first layer 313 is a layer containing an organic compound and an inorganic compound.

[0239] The inorganic compound is an alkali metal salt or an alkaline earth metal salt, preferably an alkali metal salt. Fluorides of alkaline metals or alkaline earth metals. The alkaline earth metal fluoride is preferably lithium fluoride. Calcium or magnesium fluoride is preferred.

[0240] The organic compound is an organic compound having electron transport properties, particularly 10 -6 cm 2 / Vs or later Organic compounds having the above electron mobility are preferred. As the material having electron transport properties, for example, the above-mentioned metal complexes and azo Examples of heterocyclic compounds include those having a benzoyl skeleton, a diazine skeleton, or a pyridine skeleton. Preferred are BPhen and NBPhen having a bipyridine skeleton such as a phenanthroline skeleton. NBPhen is particularly preferred.

[0241] As described above, in the light-emitting element of one embodiment of the present invention, the refractive index of the first layer 313 is set to be equal to the refractive index of the surrounding material. and the fluorination of the alkali metal or alkaline earth metal can be reduced to a level greater than that In the case of a light-emitting element in which the concentration of the substance is greater than 0 vol% and less than 95 vol%, It is possible to improve the luminous efficiency of the element. The first layer 313 containing 50 vol % or more of a metal salt provides a light emitting device with improved driving voltage. It is possible.

[0242] <Configuration example of light-emitting element> 35B is a diagram illustrating a light-emitting element according to one embodiment of the present invention. The device has an anode 401, a cathode 402, and an EL layer 403. The EL layer 403 is an emitting layer. 35(B) shows the case where the first layer is an electron transport layer. This example illustrates the case.

[0243] In FIG. 35(B), the electron transport layer is a first electron transport layer 414-1, a second electron transport layer 414-2, and a The first layer 313 in FIG. 35(A) is the second layer 14-2. The first electron transport layer 414-1 corresponds to the electron transport layer 414-2. The electron transport layer does not contain fluorides of alkaline earth metals.

[0244] The EL layer 403 also includes a hole injection layer 411, a hole transport layer 412, an electron injection layer 415, etc. It may have.

[0245] In FIG. 35(B), a hole injection layer 411, a hole transport layer 412, and a light emitting layer 413 are formed in this order from the anode 401 side. 13, the first electron transport layer 414-1, the second electron transport layer 414-2 and the electron injection layer 41 5 is illustrated, the light-emitting element of one embodiment of the present invention can be Even if the structure has functional layers other than the second electron transport layer 414-2 and the light-emitting layer 413, The structure may be such that one or more of the other layers are not included. 02, a hole injection layer 411, a hole transport layer 412, a light emitting layer 413, a first electron transport layer 414- For the electron-injecting layer 1 and the electron-injecting layer 415, the materials exemplified in Embodiment 1 can be used.

[0246] The above configuration may be appropriately combined with other embodiments or other configurations in this embodiment. is possible.

[0247] (Embodiment 3) In this embodiment, a low refractive index layer is also provided between the light emitting layer 314 and the anode 310. 45, the structure between the light-emitting layer 314 and the cathode 311 will be described. The details are the same as those in the second embodiment, so the description will be omitted. Please refer to the description in the second embodiment. In this embodiment, the EL layer 312 has a low refractive index between the anode and the light-emitting layer. The second layer 315 is a low refractive index layer between the light emitting layer and the cathode. This makes it possible to provide a light-emitting element with further improved luminous efficiency.

[0248] In this embodiment, in addition to the first layer 313 which is a layer with a low refractive index as shown in FIG. A second layer 315, which is a layer with a low refractive index, is provided between the light-emitting layer 314 and the anode 310. The layer 315 is made of a first substance that is a substance containing fluorine and a second substance that is an organic compound with a hole transporting property. The second layer 315 is a layer containing the first substance and a third substance that exhibits electron accepting properties to the second substance. By including the first substance containing fluorine, it is possible to make the layer have a low refractive index.

[0249] In addition, a second substance which is an organic compound having a hole transporting property and a compound having an electron accepting property in the second substance are By including the third material exhibiting the above property, the second layer 315 has the property of injecting holes from the electrode and It is a layer with excellent hole transport properties.

[0250] The presence of the first substance is due to the interaction of the second substance with the third substance. The low refractive index of the first material does not significantly affect the injection and hole transport properties. The second layer 315 can be made to have both hole injection and transport properties. The second layer 315, which is a layer having excellent hole injection and hole transport properties, is in contact with the anode. It can function as an input layer.

[0251] The second layer 315 may have a HOMO level depending on the HOMO level of the organic compound selected as the second substance. In some cases, the driving voltage may increase compared to a film that does not contain the first substance. A second material and a third material, which do not contain the first material, are in contact with the cathode side surface of the second layer 315. It is possible to reduce this effect by forming a third layer consisting of only the material. In this case, the second material and the third material used in the third layer are the same as those used in the second layer 315. The second and third substances may be the same or different.

[0252] In addition, the film constituting the second layer 315 has a density of 1.0×10 18 spins / cm 3 More than Since good properties can be obtained by having a high spin density, the spin density of the second layer 315 is 1.0×10 18 spins / cm 3 The spin density is measured by ESR method. It can be measured by the following, and it increases or decreases depending on the content and type of the first substance to the third substance. do.

[0253] The first substance containing fluorine may be an alkali metal fluoride, an alkaline earth metal fluoride, or is preferably an alkyl fluoride. In particular, lithium fluoride, magnesium fluoride and and calcium fluoride.

[0254] The third substance may be a transition metal oxide, a metal oxide belonging to Groups 4 to 8 of the periodic table, or a metal oxide. It is preferred that the compound be one or more of an oxide of a metal or an organic compound having an electron-withdrawing group. Specifically, titanium oxide, vanadium oxide, tantalum oxide, molybdenum oxide tungsten oxide, rhenium oxide, ruthenium oxide, chromium oxide, zirconium Hafnium oxide, silver oxide, 7,7,8,8-tetracyano-2,3,5 ,6-Tetrafluoroquinodimethane, Chloranil, 2,3,6,7,10,11-Hexa Cyano-1,4,5,8,9,12-hexaazatriphenylene, 1,3,4,5,7, 8-Hexafluorotetracyano-naphthoquinodimethane, α,α',α''-1,2,3 -Cyclopropanetriylidenetris[4-cyano-2,3,5,6-tetrafluorobenzyl] Among these, molybdenum Oxides are preferred because they have excellent electron acceptance and high stability.

[0255] The second substance, which is an organic compound having a hole-transporting property, is Although the organic compounds having the above-mentioned structure can be used, π-electron-rich heteroaromatic It is particularly preferable that the HOMO level is -5.7 If the material has a valence of -5.5 eV or more, more preferably -5.5 eV, there is no increase in the driving voltage, and it is more preferable. This can provide a light emitting element with excellent characteristics.

[0256] The refractive index of the second layer 315 can be changed by changing the content of the first substance. However, if the refractive index of the second layer 315 is 1.70 or less, the effect of improving the luminous efficiency is high. It is preferable that the content of the first substance in the second layer 315 is Even if the refractive index of the layer is larger than the specified value, it does not significantly affect the characteristics of the light emitting element. One of the features of this configuration is that it can be

[0257] Furthermore, if the second layer 315 comes into contact with the light-emitting layer 314, the light may be quenched. Preferably, there is a hole transport layer between layer 315 and light-emitting layer 314 .

[0258] The second layer 315 is located within an optical distance of approximately 1 / 4λ from the interface of the light-emitting layer on the anode side. On the other hand, the interface between the second layer 315 and the anode is preferably located at a position It is preferable to set it so that it is approximately 1 / 4λ.

[0259] The light-emitting device having such a configuration has a first low-refractive index layer present on the anode side and the cathode side. The effects of the layer 313 and the second layer 315 make it possible to obtain a light emitting element with very high efficiency. can.

[0260] (Fourth embodiment) In this embodiment mode, a light-emitting element having a different structure from that of the light-emitting element shown in Embodiment 1 is The light emitting mechanism of the light emitting element will be described below with reference to FIGS. 4 and 5, the parts having the same functions as those shown in FIG. 1(A) are denoted by the same reference numerals. In some cases, the hatch pattern is used and the symbols are omitted. Also, parts with similar functions are indicated by The same reference numerals are used and detailed descriptions thereof may be omitted.

[0261] <Configuration example 1 of light-emitting element> FIG. 4A is a schematic cross-sectional view of the light emitting element 250. FIG.

[0262] The light-emitting element 250 shown in FIG. 4A has a pair of electrodes (electrodes 101 and 102) between them. , a plurality of light-emitting units (in FIG. 4(A), light-emitting unit 106 and light-emitting unit 1 In the light-emitting element 250, the electrode 101 functions as an anode, and the electrode The following description will be given assuming that 102 functions as a cathode, but the configuration of the light emitting element 250 is as follows: The opposite is also fine.

[0263] In addition, in the light-emitting element 250 shown in FIG. 4(A), the light-emitting unit 106 and the light-emitting unit 108 are stacked, and a charge is generated between the light-emitting unit 106 and the light-emitting unit 108. The light-emitting unit 106 and the light-emitting unit 108 have the same structure. The configuration may be different.

[0264] The light emitting element 250 has a light emitting layer 120 and a light emitting layer 170. In addition to the light-emitting layer 170, the knit 106 includes a hole injection layer 111, a hole transport layer 112, an electron transport layer The light-emitting unit 108 also includes an emissive layer 120. In addition to the above, a hole injection layer 116, a hole transport layer 117, an electron transport layer 118, and an electron injection layer 11 It has 9.

[0265] The charge generation layer 115 is formed by adding an acceptor material, which is an electron acceptor, to a hole transport material. Even if the electron transport material is an electron donor, a donor material may be added to the electron transport material. Alternatively, both of these structures may be stacked.

[0266] When the charge generation layer 115 contains a composite material of an organic compound and an acceptor substance, the The composite material that can be used for the hole-injection layer 111 shown in Embodiment 1 is used as the composite material. The organic compounds include aromatic amine compounds, carbazole compounds, aromatic carbonized compounds, and the like. Various compounds such as hydrogen and polymer compounds (oligomers, dendrimers, polymers, etc.) are used. As for organic compounds, those with a hole mobility of 1×10 -6 cm 2 / Vs However, it is preferable to use a substance having a higher hole transporting property than an electron transporting property. Other materials may be used as long as they are compatible with the organic compound and the acceptor material. The material has excellent carrier injection and carrier transport properties, allowing for low voltage and low current operation. In addition, the anode side of the light-emitting unit is in contact with the charge generating layer 115. In this case, the charge generation layer 115 also serves as a hole injection layer or a hole transport layer for the light-emitting unit. Therefore, the light-emitting unit does not need to have a hole injection layer or a hole transport layer. Alternatively, when the cathode side surface of the light-emitting unit is in contact with the charge generating layer 115, The charge generation layer 115 also serves as an electron injection layer or an electron transport layer for the light-emitting unit. Therefore, the light-emitting unit does not have an electron injection layer or an electron transport layer. is also good.

[0267] The charge generation layer 115 may be a layer containing a composite material of an organic compound and an acceptor substance, or another layer containing a compound of an organic compound and an acceptor substance. For example, the organic EL element may be formed as a laminated structure in which layers made of the organic EL element are combined. A layer including a composite material of a compound and an acceptor substance and a layer including a compound selected from electron donor substances. The compound may be formed by combining a layer containing the compound with a compound having a high electron transporting property. A layer containing a composite material of an organic compound and an acceptor substance and a layer containing a transparent conductive film are combined. It may be formed by combining the above.

[0268] The charge generating layer 115 sandwiched between the light emitting unit 106 and the light emitting unit 108 When a voltage is applied between the electrode 101 and the electrode 102, electrons are injected into one of the light-emitting units, It is sufficient if the hole is injected into the other light-emitting unit. For example, in FIG. 4(A), When a voltage is applied so that the potential of electrode 101 is higher than the potential of electrode 102, The charge generating layer 115 injects electrons into the light-emitting unit 106 and holes into the light-emitting unit 108. Enter.

[0269] From the viewpoint of light extraction efficiency, the charge generation layer 115 is transparent to visible light (specifically, It is preferable that the charge generating layer 115 has a visible light transmittance of 40% or more. The charge generating layer 115 has a lower conductivity than the pair of electrodes (electrodes 101 and 102). It still works.

[0270] By forming the charge generating layer 115 using the above-mentioned materials, when a light emitting layer is laminated, In this case, the increase in the driving voltage can be suppressed.

[0271] In addition, in FIG. 4A, a light emitting element having two light emitting units has been described. However, it can also be applied to light-emitting devices in which three or more light-emitting units are stacked. As shown in the light-emitting element 250, a plurality of light-emitting units are disposed between a pair of electrodes, and a charge generating layer is formed. By separating the layers, high brightness light emission is possible while keeping the current density low. A light-emitting element with a long life and low power consumption can be realized. .

[0272] In each of the above configurations, the gates used in the light-emitting units 106 and 108 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 function of emitting light of the same color. When the material is included, the light emitting element 250 becomes a light emitting element that exhibits high light emitting luminance with a small current value. It is more preferable that the light-emitting units 106 and 108 emit light of different colors. When the light-emitting element 250 includes a guest material having a light-emitting function, the light-emitting element 250 can emit multicolor light. In this case, either one of the light-emitting layer 120 and the light-emitting layer 170 or In both cases, the light emitting element 250 is formed by using a plurality of light emitting materials with different emission wavelengths. The emission spectrum is a composite of light with different emission peaks, so Both result in an emission spectrum with two maxima.

[0273] The above-mentioned structure is also suitable for obtaining white light emission. By making the lights complementary to each other, white light can be emitted. The resulting white light is highly luminescent, or at least has red, green, and blue components. It is preferable to select a suitable material.

[0274] In addition, in the case of a light-emitting element in which three or more light-emitting units are stacked, the The guest materials may emit light of the same color or different colors. In the case where a plurality of light-emitting units are included, the emitted colors of the light emitted by the plurality of light-emitting units are Compared to other colors, high luminance can be obtained with a small current value. The composition can be suitably used to adjust the luminous color. This is suitable when using a guest material that exhibits a luminescent color. For example, In this case, two light-emitting units having fluorescent materials of the same color are used, and one light-emitting unit having a different luminescent color from the fluorescent material is used. By forming a light-emitting unit having a phosphorescent material that exhibits fluorescence and phosphorescence in a single layer, the intensity of the fluorescence and phosphorescence can be enhanced. In other words, the intensity of the emitted color can be adjusted by changing the number of light-emitting units. It is possible.

[0275] In the case of a light-emitting device having two layers of such fluorescent light-emitting units and one layer of phosphorescent light-emitting unit, blue It contains two light-emitting units containing color fluorescent materials and one light-emitting unit containing yellow phosphorescent material. Two layers of light-emitting units containing a light-emitting element or a blue fluorescent material and two layers of light-emitting units containing a red phosphorescent material and a green phosphorescent material are used. a light-emitting device having one light-emitting layer unit containing a blue fluorescent material, two light-emitting layers containing a red phosphorus fluorescent material, and a light-emitting device having one light-emitting layer unit including a phosphorescent material, a yellow phosphorescent material, and a green phosphorescent material; This is preferable because white light can be efficiently emitted.

[0276] In addition, at least one of the light-emitting layer 120 and the light-emitting layer 170 is further divided into layers, Each divided layer may contain a different light-emitting material. Alternatively, at least one of the light-emitting layers 170 may be composed of two or more layers. For example, the first light-emitting layer and the second light-emitting layer can be laminated in this order from the hole transport layer side to form the light-emitting layer. In this case, a material having hole transport properties is used as the host material of the first light-emitting layer, and a material having hole transport properties is used as the host material of the second light-emitting layer. In this case, a material having an electron transporting property is used as the host material. The light-emitting material contained in the light-emitting layer and the second light-emitting layer may be the same material or different materials. Even if a material has the function of emitting light of the same color, it may have the function of emitting light of different colors. A plurality of light-emitting materials each having the function of emitting light of a different color may be used. By using the above configuration, it is possible to obtain white light with high color rendering properties that is composed of three primary colors or four or more luminescent colors. It is also possible.

[0277] At least one of the multiple units has the structure shown in the first embodiment. By applying this composition, it is possible to provide a light emitting device with good light extraction efficiency. Specifically, it is preferable that the light-emitting layer 170 has a low refractive index in the region of 0 nm or more and λ / 2 or less. In FIG. 4, it is particularly preferable that the hole injection layer 111 also serves as a low refractive index layer.

[0278] Furthermore, the light-emitting layer 120 of the light-emitting unit 108 is formed by adding a guest The guest material 121 is a fluorescent material. , as explained below.

[0279] <Light Emitting Mechanism of Light Emitting Layer 120> The light emitting mechanism of the light emitting layer 120 will be explained below.

[0280] Electrons injected from a pair of electrodes (electrodes 101 and 102) or a charge generating layer and The recombination of the guest material 1 and the electron hole in the light-emitting layer 120 generates an exciton. Since the host material 122 is present in large amounts compared to 21, exciton generation results in almost An excited state is formed in the material 122. Note that an exciton is a pair of carriers (electrons and holes). That is the thing.

[0281] When the excited state of the formed host material 122 is a singlet excited state, the host material 12 Singlet excitation energy is transferred from the S1 level of 2 to the S1 level of the guest material 121. As a result, the singlet excited state of the guest material 121 is formed.

[0282] Since the guest material 121 is a fluorescent material, the singlet excited state in the guest material 121 is Once formed, the guest material 121 quickly emits light. For this purpose, it is preferable that the guest material 121 has a high fluorescence quantum yield. In 1, the same applies when carriers recombine and the resulting excited state is a singlet excited state. is.

[0283] Next, when carrier recombination forms a triplet excited state of the host material 122, In this case, the energy levels of the host material 122 and the guest material 121 are The correlation between the positions is shown in Figure 4(C). The notations and symbols in Figure 4(C) are as follows: The T1 level of the host material 122 is lower than the T1 level of the guest material 121. 4C shows this case, but the T1 level of the host material 122 may be higher than the T1 level of the guest material 121.

[0284] Guest (121): Guest material 121 (fluorescent material) Host (122): Host material 122 ·S FG : S1 level of guest material 121 (fluorescent material) T FG: T1 level of guest material 121 (fluorescent material) ·S FH : S1 level of the host material 122 T FH : T1 level of the host material 122 Energy

[0285] As shown in Figure 4(C), triplet-triplet annihilation (TTA) Triplets generated by carrier recombination are generated by Excitons interact with each other, transferring excitation energy and exchanging spin angular momentum. As a result, the S1 level (S FH ) has an energy of A reaction occurs in which the host material 122 is converted into a singlet exciton (see Figure 4(C) TTA). The singlet excitation energy of FH from a lower energy guest material121 S1 level (S FG ) (see Route E1 in Figure 4(C)), and the guest A singlet excited state of the material 121 is formed, and the guest material 121 emits light (Emissio n).

[0286] When the density of triplet excitons in the light-emitting layer 120 is sufficiently high (for example, 1×10 12 cm -3 In the above, the quenching of the triplet excitons alone is ignored, and the two near-field Only reactions involving adjacent triplet excitons can be considered.

[0287] Furthermore, when carriers recombine in the guest material 121 to form a triplet excited state, However, the triplet excited state of the guest material 121 is thermally deactivated, making it difficult to utilize it for light emission. However, the T1 level (T FH) is the T1 equivalent of guest material 121 Place(T FG ), the triplet excitation energy of guest material 121 is lower than that of guest material 1 21 T1 levels (T FG ) to the T1 level (T FH ) Energy transfer (See route E2 in Figure 4(C)) and then used for TTA.

[0288] That is, the host material 122 converts triplet excitation energy into singlet excitation energy by TTA. It is preferable that the light-emitting layer 120 has a function of converting the generated light into energy. A portion of the triplet excitation energy is converted to singlet excitation energy by TTA in the host material 122. The singlet excitation energy is converted into the guest material 121, and the guest material 121 is transferred to the guest material 121, thereby producing fluorescence. To achieve this, the S1 level (S FH ) is the S1 level (S FG ) is preferable. The T1 level (T FH ) is the T1 level (T FG ) lower It is preferable.

[0289] In particular, the T1 level (T FG ) is the T1 level of the host material 122 ( T FH ), the weight of the guest material 121 relative to the host material 122 The ratio is preferably low. Specifically, when the host material is 122, the guest material is 1 The weight ratio of guest material 1 to guest material 21 is preferably greater than 0 and less than or equal to 0.05. The probability of carrier recombination in the host material 122 can be reduced. T1 level (TFH ) to the T1 level (T FG ) energy transfer occurs This can reduce the probability of this happening.

[0290] The host material 122 may be composed of a single compound or a plurality of compounds. It may be formed.

[0291] In addition, the light-emitting units 106 and 108 have guest materials with different emission colors. In this case, the emission from the light-emitting layer 120 has a peak in the shorter wavelength side than the emission from the light-emitting layer 170. It is preferable to use a material having a high triplet excitation energy level. The light-emitting element used in this method tends to have a tendency to deteriorate quickly in brightness. By using TA, it is possible to provide a light-emitting element with little deterioration in luminance.

[0292] <Configuration example 2 of light-emitting element> FIG. 5A is a schematic cross-sectional view of the light emitting element 252. FIG.

[0293] The light emitting element 252 shown in FIG. 5A has a pair of electrodes, similar to the light emitting element 250 shown above. A plurality of light-emitting units (in FIG. 5(A), light-emitting elements) are disposed between the electrodes 101 and 102. The light unit 106 and the light-emitting unit 110 are included. At least one light-emitting unit is The light-emitting unit 106 and the light-emitting unit 110 have the same structure as the EL layer 100. may be of the same or different configurations.

[0294] In addition, in the light-emitting element 252 shown in FIG. 5(A), the light-emitting unit 106 and the light-emitting unit The light-emitting unit 106 and the light-emitting unit 110 are stacked together, and a charge generating layer is formed between the light-emitting unit 106 and the light-emitting unit 110. For example, the EL layer 100 is preferably used in the light-emitting unit 106. It's nice.

[0295] The light emitting element 252 also includes a light emitting layer 140 and a light emitting layer 170. In addition to the light-emitting layer 170, the knit 106 includes a hole injection layer 111, a hole transport layer 112, an electron transport layer The light-emitting unit 110 also includes a light-emitting layer 140. In addition to the above, a hole injection layer 116, a hole transport layer 117, an electron transport layer 118, and an electron injection layer 11 It has 9.

[0296] At least one of the multiple units has the structure shown in the first embodiment. By applying this composition, it is possible to provide a light emitting device with good light extraction efficiency. Specifically, it is preferable that the light-emitting layer 170 has a low refractive index in the region of 0 nm or more and λ / 2 or less. In FIG. 5, it is particularly preferable that the hole injection layer 111 also serves as a low refractive index layer.

[0297] The light-emitting layer 140 of the light-emitting unit 110 is composed of a guest material 1 as shown in FIG. The host material 142 includes an organic compound 142_ The light-emitting layer 140 includes the guest material 141 and the organic compound 142_2. The following description will be given assuming that 1 is a phosphorescent material.

[0298] <Light Emitting Mechanism of Light Emitting Layer 140> Next, the light emitting mechanism of the light emitting layer 140 will be described below.

[0299] The organic compound 142_1 and the organic compound 142_2 contained in the light-emitting layer 140 form an exciplex. Form.

[0300] The combination of organic compound 142_1 and organic compound 142_2 forms an exciplex with each other. Any combination is acceptable as long as one of the compounds has a hole transporting property. It is more preferable that the other is a compound having electron transport properties.

[0301] The organic compound 142_1, the organic compound 142_2, and the guest material in the light-emitting layer 140 The correlation of the energy level with 141 is shown in Figure 5(C). The symbols and symbols are as follows: Guest (141): Guest material 141 (phosphorescent material) ·Host(142_1): Organic compound 142_1 (host material) ·Host(142_2): Organic compound 142_2 (host material) T PG : T1 level of guest material 141 (phosphorescent material) ·S PH1 : S1 level of organic compound 142_1 (host material) T PH1 :T1 level of organic compound 142_1 (host material) ·S PH2 : S1 level of organic compound 142_2 (host material) T PH2 :T1 level of organic compound 142_2 (host material) ·S PE : S1 level of the exciplex T PE :T1 level of exciplex Energy

[0302] The organic compound 142_1 and the organic compound 142_2 form an exciplex, and the S 1 level (S PE ) and T1 level (T PE ) are adjacent energies (Figure 5(C) See Route E3).

[0303] One of the organic compounds 142_1 and 142_2 receives a hole and the other receives an electron. Alternatively, when one of the two is excited, it quickly forms an exciplex. Therefore, the exciplex in the light-emitting layer 140 Most of the excited molecules exist as exciplexes. The excited energy levels of exciplexes (S PE Also is T PE ) is a host material (organic compound 142_1 and organic compound 142_2) that forms an exciplex. 42_2) S1 level (S PH1 and S PH2 ) and therefore has a lower excitation energy This allows the formation of an excited state in the host material 142. The driving voltage of the element can be reduced.

[0304] And the (S PE ) and (T PE ) and the energy of the guest material 141 (phosphorescent material) (see routes E4 and E5 in Figure 5(C)), and light emission is obtained. (Emission).

[0305] In addition, the T1 level of the exciplex (T PE ) is the T1 level (T PG )twist By doing so, the singlet excitation energy and and triplet excitation energy to the S1 level (S PE ) and T1 level (T PE )mosquito The T1 level (T PG ) can transfer energy to

[0306] In addition, in order to efficiently transfer excitation energy from the exciplex to the guest material 141, , the T1 level of the exciplex (TPE ) are each organic compound that forms an exciplex (organic compound 14 T1 levels (T PH1 and T PH2 ) or It is preferable that the organic compound 142_1 and the organic compound 142_2 are smaller than the organic compound 142_1. Compound 142_2) is less likely to quench the triplet excitation energy of the exciplex. Energy transfer from the exciplex to the guest material 141 occurs efficiently.

[0307] In addition, the organic compound 142_1 and the organic compound 142_2 efficiently form an exciplex. In order to achieve this, the HOMO level of one of the organic compounds 142_1 and 142_2 must be The HOMO level is higher than the other, and the LUMO level of one is higher than the LUMO level of the other. For example, the organic compound 142_1 has a hole transporting property, and the organic compound 142_2 has a hole transporting property. When the organic compound 142_1 has electron transport properties, the HOMO level of the organic compound 142_2 It is preferable that the LUMO level of the organic compound 142_1 is higher than the HOMO level of the organic compound 142_2. It is preferable that the LUMO level of the organic compound 142_2 is higher than that of the organic compound 142_3. When organic compound 142 has hole transporting properties and organic compound 142_1 has electron transporting properties, organic compound 1 The HOMO level of 42_2 is preferably higher than the HOMO level of the organic compound 142_1. , the LUMO level of organic compound 142_2 is higher than the LUMO level of organic compound 142_1. Specifically, it is preferable that the HOMO level of the organic compound 142_1 and the HOMO level of the organic compound 142_2 are The energy difference between the HOMO level of _2 is preferably 0.05 eV or more, and more preferably The electron transport potential is preferably 0.1 eV or more, and more preferably 0.2 eV or more. The energy difference between the LUMO level of organic compound 142_1 and the LUMO level of organic compound 142_2 is Preferably, it is 0.05 eV or more, more preferably 0.1 eV or more, and even more preferably Preferably, it is 0.2 eV or more.

[0308] In addition, the combination of organic compound 142_1 and organic compound 142_2 has hole transport properties. When a compound having electron transport properties is used in combination with a compound having electron transport properties, the mixing ratio Specifically, the carrier balance can be easily controlled by using a material having hole transport properties. The weight ratio of the compound having electron transport properties to the compound having electron transport properties is preferably in the range of 1:9 to 9:1. In addition, by having this configuration, the carrier balance can be easily controlled, The carrier recombination region can also be easily controlled.

[0309] By configuring the light-emitting layer 140 as described above, the guest material 141 (phosphorescent material ) can be efficiently obtained.

[0310] The above-described routes E3 to E5 are referred to as ExTET (Ex It is sometimes called plex-triplet energy transfer. In other words, the light-emitting layer 140 transfers the excitation energy from the exciplex to the guest material 141. In this case, it is not necessarily T PE From S PE High efficiency of reverse intersystem crossing is required No, S PE The quantum yield of light emission from the material does not need to be high, so a wide range of materials can be selected. It becomes possible.

[0311] Furthermore, the light emitted from the light-emitting layer 170 has a peak at a shorter wavelength than the light emitted from the light-emitting layer 140. It is preferable that the light-emitting element has a structure including a phosphorescent material that emits light of a short wavelength. Therefore, by using fluorescent light for short wavelengths, A light-emitting element with little deterioration in luminance can be provided.

[0312] <Examples of materials that can be used for the light-emitting layer> Next, materials that can be used for the light-emitting layer 120, the light-emitting layer 140, and the light-emitting layer 170 will be described. The following explains the details.

[0313] <Materials that can be used for the light-emitting layer 120> In the light-emitting layer 120, the host material 122 is present in the largest amount by weight, and the guest material 121 The fluorescent material is dispersed in the host material 122. The S1 level of the host material 122 is The S1 level of the host material 122 is higher than the S1 level of the fluorescent material 121. It is preferable that the T1 level is lower than the T1 level of the source material 121 (fluorescent material).

[0314] In the light-emitting layer 120, the guest material 121 is not particularly limited, but may be anthracene. derivatives, tetracene derivatives, chrysene derivatives, phenanthrene derivatives, pyrene derivatives, Rylene derivatives, stilbene derivatives, acridone derivatives, coumarin derivatives, phenoxazine Derivatives, phenothiazine derivatives, etc. are preferred, and the fluorescent compounds shown in the first embodiment are preferred. It can be used appropriately.

[0315] In addition, materials that can be used as the host material 122 in the light-emitting layer 120 include: Although there is no particular limitation, for example, tris(8-quinolinolato)aluminum(III) (abbreviation : Alq), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq3), bis(10-hydroxybenzo[h]quinolinato)beryllium(II)( Abbreviation: BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato) ) Aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II)( Abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phenolato]zinc(II) ( abbreviation: ZnBTZ), metal complexes such as 2-(4-biphenylyl)-5-(4-tert- butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5 -(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene OXD-7, 3-(4-biphenylyl)-4-phenyl-5-(4-te rt-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 2,2',2' '-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazoline) TPBI), bathocuproine (BCP), 9-[4-(5-phenyl [(1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation Heterocyclic compounds such as 4,4'-bis[N-(1-naphthyl)-N-phenyl] N,N'-bis(3-methylamino)biphenyl (abbreviation: NPB or α-NPD) phenyl)-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) and other aromatic amine compounds. In addition, anthracene derivatives, phenanthrene derivatives, pyrene derivatives, and chrysene derivatives condensed polycyclic aromatic compounds such as fluorine-containing fluorine ions, fluorine-containing ... 9,10-diphenylanthracene (abbreviation: DPAnth), N,N-diphenyl -9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole-3 -amine (abbreviation: CzA1PA), 4-(10-phenyl-9-anthryl)triphenyl Diazolamine (abbreviation: DPhPA), 4-(9H-carbazol-9-yl)-4'-(10 -phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), N,9-diphenyl Phenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazo N,9-diphenyl-N-{4-[(10- Phenyl-9-anthryl)phenyl]phenyl}-9H-carbazol-3-amine( Abbreviation: PCAPBA), N,9-diphenyl-N-(9,10-diphenyl-2-anthracene) (aryl)-9H-carbazol-3-amine (abbreviation: 2PCAPA), 6,12-dimethoxamine si-5,11-diphenylchrysene, N,N,N',N',N'',N'',N''', N'''-Octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraaza mine (abbreviation: DBC1), 9-[4-(10-phenyl-9-anthryl)phenyl]- 9H-Carbazole (abbreviation: CzPA), 3,6-diphenyl-9-[4-(10-phenyl) [Nyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: DPCzPA), 9, 10-Bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 9,10 -Di(2-naphthyl)anthracene (abbreviation: DNA), 2-tert-butyl-9,10 -Di(2-naphthyl)anthracene (t-BuDNA), 9,9'-bianthryl (abbreviation: BANT), 9,9'-(stilbene-3,3'-diyl)diphenanthrene ( abbreviation: DPNS), 9,9'-(stilbene-4,4'-diyl)diphenanthrene (abbreviation Name: DPNS2), 3,3',3''-(benzene-1,3,5-triyl)tripylene (abbreviation: TPB3), etc. In addition, from among these and known substances, A substance having an energy gap larger than the energy gap of the guest material 121 One or more of the above may be selected and used.

[0316] The light-emitting layer 120 may be composed of two or more layers. When the light-emitting layer 120 is formed by laminating the first light-emitting layer and the second light-emitting layer in this order from the hole transport layer side, a substance having hole transport properties is used as a host material for the first light-emitting layer, and a substance having hole transport properties is used as a host material for the second light-emitting layer For example, a substance having an electron transport property is used as the light emitting element.

[0317] In the light-emitting layer 120, the host material 122 is composed of one kind of compound. Alternatively, the light-emitting layer 120 may be made up of a single compound or a plurality of compounds. The layer may contain materials other than the host material 122 and the guest material 121 .

[0318] <Materials that can be used for the light-emitting layer 140> In the light-emitting layer 140, the host material 142 is present in the largest amount by weight, and the guest material 141 The host material 142 (phosphorescent material) of the light-emitting layer 140 is dispersed in the host material 142. The T1 level of the organic compound 142_1 and the organic compound 142_2 is the T It is preferable that the level is higher than 1.

[0319] Organic compounds 142_1 include zinc and aluminum metal complexes, as well as oxadiazo derivatives, triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzyl Dibenzoquinoxaline derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, pyrimidin derivatives, triazine derivatives, pyridine derivatives, bipyridine derivatives, phenanthroline derivatives Other examples include aromatic amines and carbazole derivatives. Specifically, the electron transporting material and the hole transporting material shown in Embodiment 1 are used. It is possible.

[0320] The organic compound 142_2 is a compound that can form an exciplex with the organic compound 142_1. Specifically, the electron transport material and the hole transport material shown in Embodiment 1 are preferably used in combination. In this case, the organic compound 142_1 and the organic compound 142_2 can be used. The emission peak of the formed exciplex is the triplet MLCT( Metal to Ligand Charge Transfer (MLC) transition absorption band, Specifically, organic compound 142_1 and organic compound 142_2 are selected so that they overlap with the absorption band on the longest wavelength side. It is preferable to select the material 142_2 and the guest material 141 (phosphorescent material). As a result, a light-emitting element with dramatically improved luminous efficiency can be obtained. In addition, when a thermally activated delayed fluorescent material is used, the absorption band on the longest wavelength side is the absorption band of the singlet state. Preferably it is a band.

[0321] As the guest material 141 (phosphorescent material), an organic compound of iridium, rhodium, or platinum is used. Metal complexes, or metal complexes, among which organic iridium complexes, e.g., iridium The orthometalated complex is preferably a 4H-triazole. Ligand, 1H-triazole ligand, imidazole ligand, pyridine ligand, pyrimidine The metal complexes include a pyrazine ligand, an isoquinoline ligand, and the like. Examples of the platinum complex include a platinum complex having a porphyrin ligand. The materials exemplified as the guest material 132 shown in 1 can be used.

[0322] The light-emitting material contained in the light-emitting layer 140 is a material capable of converting triplet excitation energy into light. The material capable of converting triplet excitation energy into luminescence is a phosphorescent material. In addition to the above, thermally activated delayed fluorescent materials are also included. In other words, it may be interpreted as a thermally activated delayed fluorescent material.

[0323] In addition, materials that exhibit thermally activated delayed fluorescence can be independently converted from triplet excited states by reverse intersystem crossing. The material may be capable of generating a doublet excited state, or may be an exciplex (or It may be made up of multiple materials that form a composite (also called an exciplex).

[0324] When the thermally activated delayed fluorescent material is composed of one kind of material, specifically, The thermally activated delayed fluorescent material shown in 1 can be used.

[0325] In addition, when a thermally activated delayed fluorescent material is used as a host material, two types of exciplexes are formed. It is preferable to use a combination of compounds of the same type. In this case, the compound forming the above-mentioned exciplex is The combination of compounds that readily accept electrons and compounds that readily accept holes is It is particularly preferred to use

[0326] <Materials that can be used for the light-emitting layer 170> The light-emitting layer 170 can be made of the same material as that used for the light-emitting layer shown in Embodiment 1. By using a material that can achieve this, a light-emitting element with high luminous efficiency can be fabricated. It is possible.

[0327] In addition, the light emission colors of the light emitting materials contained in the light emitting layers 120, 140, and 170 are There is no limitation, and they may be the same or different. The light emitted from each is mixed. For example, if the colors of the two lights are complementary to each other, The element can provide white light. The emission peak wavelength of the luminescent material contained in the luminescent layer 170 is shorter than that of the luminescent material contained in the luminescent layer 170. It is preferable that:

[0328] The light-emitting units 106, 108, 110, and the charge generating The layer 115 can be formed by a deposition method (including a vacuum deposition method), an inkjet method, a coating method, a gravure printing method, etc. It can be formed by the method described above.

[0329] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. You can be there.

[0330] (Embodiment 5) FIG. 6(A) is a top view showing a light-emitting device, and FIG. 6(B) is a cross-sectional view of FIG. 6(A) taken along lines AB and CD. This light emitting device is a cross-sectional view of a light emitting element. The illustrated drive circuit section (source side drive circuit) 601, pixel section 602, drive circuit section (gate side The driving circuit 603 is also included. 604 is a sealing substrate, 625 is a desiccant, and 605 is a shielding material. The inside surrounded by the sealing material 605 is a space 607 .

[0331] The lead wiring 608 is connected to the source side driver circuit 601 and the gate side driver circuit 603. The wiring is for transmitting signals, and the FPC (flexible printed circuit board) is the external input terminal. Video signal, clock signal, start signal, reset signal, etc. from the input circuit 609 Although only the FPC is shown here, this FPC has a printed wiring board. Even if a printed wiring board (PWB) is installed The light emitting device in this specification includes not only the light emitting device itself but also an FPC or This includes the state where the PWB is installed.

[0332] Next, a cross-sectional structure of the light emitting device will be described with reference to FIG. The driving circuit section and the pixel section are formed in the pixel section. A circuit 601 and one pixel in a pixel portion 602 are shown.

[0333] The source side driver circuit 601 includes an n-channel TFT 623 and a p-channel TFT 624. The drive circuit is a CMOS circuit that combines various CMOS circuits, P It may be formed of a MOS circuit or an NMOS circuit. Although this shows a driver integrated type in which the driver circuit is formed on the board, this is not necessarily required. It can also be formed externally.

[0334] The pixel section 602 includes a switching TFT 611, a current control TFT 612, and its drain. The pixel includes a first electrode 613 electrically connected to the first An insulator 614 is formed to cover the end of the electrode 613. It can be formed by using a photosensitive resin film of a mold.

[0335] In addition, in order to improve the coverage of the film formed on the insulator 614, The upper end or the lower end of the insulator 614 is formed to have a curved surface. When photosensitive acrylic is used as the material, it is possible to make only the upper end of the insulator 614 curved. The radius of curvature of the curved surface is preferably 0.2 μm or more and 0.3 μm or less. The border 614 may be either a negative or positive photosensitive material.

[0336] An EL layer 616 and a second electrode 617 are formed on the first electrode 613. Here, the material used for the first electrode 613 functioning as an anode is a material having a work function of It is desirable to use a large material, for example, an ITO film or an indium-silicon-containing film. Indium tin oxide film, indium oxide film containing 2wt% to 20wt% zinc oxide, nitride In addition to single layer films such as titanium film, chromium film, tungsten film, Zn film, and Pt film, titanium nitride film and 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 dioxide film can be used. The resistance is low, good ohmic contact can be achieved, and it can also function as an anode. This can be done.

[0337] The EL layer 616 can be formed by a deposition method using a deposition mask, an inkjet method, or a spin coating method. The EL layer 616 can be formed by various methods such as the above. The polymer may be a polymer or a polymer compound (including an oligomer or a dendrimer).

[0338] Furthermore, a material used for the second electrode 617 formed on the EL layer 616 and functioning as a cathode As the material, materials with a small work function (Al, Mg, Li, Ca, or their alloys or compounds) It is preferable to use a material such as MgAg, MgIn, or AlLi. When light generated in the EL layer 616 is to be transmitted to the second electrode 617, a thin film is used as the second electrode 617. Thin metal films and transparent conductive films (ITO, containing 2 wt% to 20 wt% zinc oxide) Indium oxide, silicon-containing indium tin oxide, zinc oxide (ZnO), etc. It is better to use layers.

[0339] The first electrode 613, the EL layer 616, and the second electrode 617 form a light-emitting element 618. The light emitting element 618 has the structure of any one of the first to fourth embodiments. It is preferable that the pixel portion is formed with a plurality of light emitting elements. In the light emitting device of the present embodiment, a light emitting device having the configuration described in any one of the first to fourth embodiments is used. The light-emitting element may include both a light-emitting element and a light-emitting element having other configurations.

[0340] Furthermore, the sealing substrate 604 is bonded to the element substrate 610 with a sealing material 605. A light emitting element is disposed in a space 607 surrounded by a sub-substrate 610, a sealing substrate 604, and a sealing material 605. 618 is provided. The space 607 is filled with a filler. In addition to cases where inert gas (nitrogen, argon, etc.) is filled, resin or desiccant or its Sometimes it is filled with both.

[0341] It is preferable to use epoxy resin or glass frit for the sealing material 605. It is desirable that these materials be as impermeable to moisture and oxygen as possible. Materials used for the sealing substrate 604 include glass substrates, quartz substrates, and FRP (Fiber Reinforced Plastics). reinforced plastics), PVF (polyvinyl fluoride), polyester A plastic substrate made of polyethylene or acrylic can be used.

[0342] As described above, the light-emitting device using the light-emitting elements described in the first and second embodiments can be obtained.

[0343] <Configuration example 1 of light-emitting device> FIG. 7 shows an example of a light-emitting device in which a light-emitting element that emits white light is formed and a coloring layer (color filter) is formed. An example of a light emitting device in which a light emitting diode (LED) filter is formed is shown.

[0344] FIG. 7A shows a substrate 1001, an underlying insulating film 1002, a gate insulating film 1003, and a gate electrode. 1006, 1007, 1008, a first interlayer insulating film 1020, and a second interlayer insulating film 1021 , a peripheral portion 1042, a pixel portion 1040, a driving circuit portion 1041, and a first electrode 102 of the light-emitting element. 4W, 1024R, 1024G, 1024B, partition 1026, EL layer 1028, light-emitting element 10, a second electrode 1029, a sealing substrate 1031, a sealing material 1032, and the like are shown.

[0345] 7(A) and 7(B) show colored layers (red colored layer 1034R, green colored layer 10 34G, blue colored layer 1034B) is provided on the transparent substrate 1033. A black matrix 1035 may be further provided. The transparent substrate 1033 is aligned and fixed to the substrate 1001. The color layer is covered with an overcoat layer 1036. In FIG. 7(A), the light The light-emitting layer emits light to the outside without passing through the colored layer, and the light-emitting layer emits light to the outside by passing through the colored layer of each color. The light that does not pass through the colored layer is white, and the light that passes through the colored layer is red, blue, or green. This allows images to be expressed using four color pixels.

[0346] In FIG. 7B, a red colored layer 1034R, a green colored layer 1034G, and a blue colored layer 103 4B) is formed between the gate insulating film 1003 and the first interlayer insulating film 1020. As shown in FIG. 7(B), the colored layer may be provided between the substrate 1001 and the sealing substrate 1031. good.

[0347] In the light emitting device described above, light is taken in toward the substrate 1001 on which the TFT is formed. The light emitting device has a bottom emission structure, but the light is taken in from the sealing substrate 1031 side. The light emitting device may have a top emission structure.

[0348] <Configuration Example 2 of Light-Emitting Device> A cross-sectional view of a top-emission type light-emitting device is shown in FIG. A connecting electrode that connects the TFT and the anode of the light-emitting element can be formed. The process is the same as that for the bottom emission type light emitting device until the third interlayer is formed. An insulating film 1037 is formed to cover the electrode 1022. This insulating film plays a role of planarization. The third interlayer insulating film 1037 may be made of the same material as the second interlayer insulating film 1021, or may be made of various materials. It can be made from a variety of materials.

[0349] The first lower electrodes 1025W, 1025R, 1025G, and 1025B of the light-emitting element are The anode is used as the cathode, but it can also be used as the cathode. In the case of an optical device, the bottom electrodes 1025W, 1025R, 1025G, and 1025B are reflective electrodes. The second electrode 1029 has a function of reflecting light and a function of transmitting light. It is preferable that the second electrode 1029 and the lower 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 similar to that described in the second embodiment. The device has a structure that allows white light to be emitted.

[0350] In FIGS. 7(A), 7(B), and 8, 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.

[0351] In the top emission structure shown in Figure 8, the colored layers (red colored layer 1034R, green colored layer The sealing can be performed by a sealing substrate 1031 provided with a blue colored layer 1034G and a blue colored layer 1034B. The sealing substrate 1031 has a black layer (black matrix) positioned between the pixels. A coloring layer (red coloring layer 1034R, green coloring layer 1035) may be provided. 034G, blue colored layer 1034B) and black layer (black matrix) are overcoated The sealing substrate 1031 may be covered with a transparent layer. .

[0352] Although an example of full-color display using four colors, red, green, blue, and white, is shown here, there is no particular limitation. Alternatively, full color display may be performed using three colors: red, green, and blue. Alternatively, full color display may be performed using four colors: red, green, blue, and yellow. A full color display may be performed.

[0353] Up to this point, we have explained about active matrix light emitting devices, but from now on we will be talking about passive light emitting devices. A pad matrix type light emitting device will be explained. 46(A) is a perspective view showing a light-emitting device, and FIG. 46(B) is a cross-sectional view of FIG. 46(A) taken along the XY line. An EL layer 955 is provided on the electrode 951 between an electrode 952 and an electrode 956. The ends of the insulating layer 953 are covered with an insulating layer 953. A partition layer 954 is provided on the insulating layer 953. The side walls of the partition layer 954 are spaced apart from one another as they approach the substrate surface. In other words, the partition layer 954 has a slope such that the distance between the partition layer 954 and the sidewall becomes narrower. The cross section is trapezoidal, and the base (which faces in the same direction as the surface direction of the insulating layer 953) The upper side (the side in contact with the insulating layer 953) faces in the same direction as the surface direction of the insulating layer 953. In this way, by providing the partition layer 954, it is possible to prevent static electricity and the like from Defects in the light-emitting element can be prevented. A light-emitting device with low power consumption using the light-emitting element described in any of Embodiments 1 to 4 It can be placed.

[0354] The light emitting device described above has a large number of minute light emitting elements arranged in a matrix. Since it is possible to control the light emission, it can be suitably used as a display device for displaying images. It is a device.

[0355] Note that this embodiment mode can be combined with other embodiment modes as appropriate.

[0356] (Embodiment 6) In this embodiment, an electronic device according to one embodiment of the present invention will be described.

[0357] Since one embodiment of the present invention is a light-emitting element using an organic EL, By using the above, it is possible to manufacture a highly reliable electronic device having a flat surface and good light emission efficiency. According to one embodiment of the present invention, a highly reliable electronic device having a curved surface and high light emission efficiency can be manufactured. Furthermore, according to one embodiment of the present invention, a flexible, highly reliable, and high-luminous efficiency LED can be obtained. You can create electronic devices.

[0358] Examples of electronic devices include television sets, desktop or notebook PCs, etc. Personal computers, computer monitors, digital cameras, digital video cameras Cameras, digital photo frames, mobile phones, portable game consoles, personal digital assistants, sound reproduction Examples include large gaming machines such as pachinko machines.

[0359] Furthermore, the light-emitting device of one embodiment of the present invention can achieve high visibility regardless of the intensity of external light. Therefore, portable electronic devices, wearable electronic devices, and It can be suitably used in a child book terminal or the like.

[0360] The mobile information terminal 900 shown in FIGS. 9A and 9B includes a housing 901, a housing 902, a display unit 90 3, and a hinge portion 905.

[0361] 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. 9(A)) as shown in Fig. 9(B). This makes it highly portable when you carry it around, and the large display area makes it easy to see when you use it. Excellent recognition.

[0362] The portable information terminal 900 has a hinge 905 that connects the housing 901 and the housing 902. A flexible display unit 903 is provided.

[0363] The light-emitting device manufactured according to one embodiment of the present invention can be used in the display portion 903. This allows the production of portable information terminals with a high yield.

[0364] The display unit 903 can display at least one of document information, still images, and moving images. When document information is displayed on the display unit, the portable information terminal 900 is used as an electronic book terminal. It can be used as follows.

[0365] When the mobile information terminal 900 is unfolded, the display portion 903 is held in a greatly curved state. For example, the radius of curvature is 1 mm or more and 50 mm or less, preferably 5 mm or more and 30 mm or less. The display unit 903 is held by the housing 901 and the other parts. Pixels are arranged continuously from 902 to 903, enabling a curved display.

[0366] The display unit 903 functions as a touch panel and can be operated with a finger or a stylus. can.

[0367] The display unit 903 is preferably configured as a single flexible display. This allows for continuous, uninterrupted display between the housing 901 and the housing 902. It should be noted that the housing 901 and the housing 902 each have a display. You may do so.

[0368] The hinge portion 905 is a part that connects the housing 901 and the housing 902 when the mobile information terminal 900 is unfolded. It is preferable to have a locking mechanism to prevent the angle from becoming larger than a predetermined angle. For example, the angle at which the door will lock (will not open any further) must be between 90 degrees and 180 degrees. Typically, the angle is 90 degrees, 120 degrees, 135 degrees, 150 degrees, or 17 degrees. 5 degrees, etc. This improves the convenience, safety, and Reliability can be improved.

[0369] If the hinge part 905 has a locking mechanism, the display part 903 can be opened without applying excessive force. Therefore, it is possible to prevent the display unit 903 from being damaged. It can be achieved.

[0370] The housing 901 and the housing 902 are provided with a power button, an operation button, an external connection port, a speaker, a microphone, and the like. It may have a ridge or the like.

[0371] A wireless communication module is provided in either the housing 901 or the housing 902. Internet, LAN (Local Area Network), Wi-Fi (registered trademark) ) (Wireless Fidelity) and other computer networks. It is possible to send and receive data.

[0372] A portable information terminal 910 shown in FIG. 9C includes a housing 911, a display unit 912, and operation buttons 913. , an external connection port 914, a speaker 915, a microphone 916, a camera 917, and the like.

[0373] The light-emitting device manufactured according to one embodiment of the present invention can be used in the display portion 912. This allows the production of portable information terminals with a high yield.

[0374] The mobile information terminal 910 has a touch sensor on the display unit 912. All operations, such as entering text, can be performed by touching the display 912 with a finger or a stylus. It can be done.

[0375] In addition, by operating the operation button 913, the power can be turned on and off, and the display on the display unit 912 can be changed. For example, you can change the type of image displayed from the main screen of the email composition screen. You can switch to the menu screen.

[0376] In addition, a detection device such as a gyro sensor or an acceleration sensor is installed inside the portable information terminal 910. By providing this, the orientation (portrait or landscape) of the mobile information terminal 910 can be determined and the screen of the display unit 912 can be displayed. The display orientation can be automatically switched. The input is made by touching the display 912, operating the operation button 913, or by voice input using the microphone 916. It can also be done by force or the like.

[0377] The mobile information terminal 910 is, for example, one or more devices selected from a telephone, a notebook, an information viewing device, etc. It has multiple functions. Specifically, it can be used as a smartphone. The information terminal 910 can be used for, for example, mobile phone calls, e-mails, viewing and creating documents, playing music, and watching videos. It can run various applications such as playback, internet communication, and games. do.

[0378] The camera 920 shown in FIG. 9(D) includes a housing 921, a display unit 922, operation buttons 923, a shutter, and a The camera 920 also has a detachable lens 926. It is attached.

[0379] The light-emitting device manufactured according to one embodiment of the present invention can be used in the display portion 922. This allows the camera to be manufactured with a high yield.

[0380] 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.

[0381] The camera 920 captures still or moving images by pressing the shutter button 924. The display unit 922 also has a function as a touch panel. It is also possible to take a picture by touching

[0382] The camera 920 can be equipped with a strobe device, a viewfinder, etc. Alternatively, these may be incorporated into the housing 921.

[0383] 10A to 10E are diagrams showing electronic devices. These electronic devices are housed in a housing 9000. , a display unit 9001, a speaker 9003, an operation key 9005 (power switch or operation switch switch), connection terminal 9006, sensor 9007 (force, displacement, position, speed, acceleration, angle Speed, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, Includes the ability to measure voltage, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared. It has a microphone 9008, etc.

[0384] A light-emitting device manufactured according to one embodiment of the present invention can be suitably used in the display portion 9001. This allows electronic devices to be manufactured with high yields.

[0385] The electronic devices shown in Figures 10(A) to 10(E) can have various functions. Functions for displaying various information (still images, videos, text images, etc.) on the display, touch panel function Functions such as displaying calendars, dates, or times, and various software (programs) ) to control processing, wireless communication function, and various computer It has the function of connecting to a data network, and the function of transmitting or receiving various data using wireless communication. The function to be performed, read the program or data recorded on the recording medium and display it on the display unit The electronic devices shown in FIGS. 10(A) to 10(E) can have the following functions. The functions are not limited to these, and other functions may also be included.

[0386] 10A shows a wristwatch-type portable information terminal 9200, and FIG. 10B shows a wristwatch-type portable information terminal 9200. 92 is a perspective view showing a terminal 9201.

[0387] The mobile information terminal 9200 shown in FIG. 10A is a terminal for mobile phone calls, e-mails, and document browsing and creation. It can be used for various applications such as music playback, internet communication, and computer games. The display surface of the display unit 9001 is curved, and the curved The portable information terminal 9200 can display information on a display surface. For example, a wireless headset can be used with the By communicating with each other, you can talk hands-free. The 9200 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. Note that the charging operation may be performed by wireless power supply without using the connection terminal 9006.

[0388] The portable information terminal 9201 shown in FIG. 10B is different from the portable information terminal shown in FIG. The display surface of the display unit 9001 is not curved. The shape is non-rectangular (circular in FIG. 10(B)).

[0389] 10(C) to 10(E) are perspective views showing a foldable mobile information terminal 9202. 10(C) is a perspective view of the mobile information terminal 9202 in an unfolded state, and FIG. 10(D) is a perspective view of the mobile information terminal 9202 in an unfolded state. The mobile information terminal 9202 changes from one of the unfolded state and the folded state to the other. 10(E) is a perspective view of the portable information terminal 9202 in a folded state. FIG.

[0390] The portable information terminal 9202 is highly portable when folded, and has a seam when unfolded. The display area of ​​the portable information terminal 9202 is wide and has no distortion, making it easy to see the display. 9001 is supported by three housings 9000 connected by hinges 9055. The two housings 9000 are bent via the hinge 9055, thereby forming a portable information terminal 9 202 can be reversibly transformed from an unfolded state to a folded state. The portable information terminal 9202 can be bent with a radius of curvature of 1 mm or more and 150 mm or less.

[0391] This embodiment mode can be combined with other embodiment modes as appropriate.

[0392] (Embodiment 7) 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. 11 and 12. By using a light-emitting element which is one embodiment of the present invention, Therefore, a highly reliable lighting device with good luminous efficiency can be manufactured.

[0393] By fabricating the light-emitting element of one embodiment of the present invention over a flexible substrate, it is possible to fabricate a light-emitting element having a curved surface. It is possible to realize electronic devices and lighting devices having light-emitting regions.

[0394] Furthermore, a light-emitting device using a light-emitting element according to one embodiment of the present invention can be used for automobile lighting. For example, lighting can be installed on the windshield, ceiling, etc.

[0395] FIG. 11(A) shows a perspective view of one side of the multifunction terminal 3500, and FIG. 11(B) shows a perspective view of the multifunction terminal 3500. 3 shows a perspective view of the other side of the multifunction terminal 3500. The multifunction terminal 3500 has a housing 350 2 incorporates a display unit 3504, a camera 3506, a light 3508, etc. The light emitting device of the embodiment can be used for lighting 3508.

[0396] The light source 3508 functions as a surface light source when the light-emitting device of one embodiment of the present invention is used. Therefore, unlike point light sources such as LEDs, light emission 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 or off. The light 3508 can be illuminated or blinked, and captured by the camera 3506. It functions as a surface light source, allowing you to take photos that look like they were taken under natural light. Cut.

[0397] The multifunction terminal 3500 shown in FIGS. 11(A) and 11(B) is the same as that shown in FIGS. 10(A) to 10(C). ) can have a variety of functions.

[0398] In addition, inside the housing 3502, a speaker, a sensor (force, displacement, position, velocity, acceleration, angle Speed, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, Includes functions to measure voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays The multifunction terminal 3500 may include a voice recorder, a microphone, etc. By providing a detection device having a sensor that detects tilt, such as a gyro or acceleration sensor, The screen display of the display unit 3504 is automatically adjusted by determining the orientation (portrait or landscape) of the functional terminal 3500. You can make it so that it switches.

[0399] The display unit 3504 can also function as an image sensor. By touching the palm or fingers to the sensor 504 and capturing an image of the palm print, fingerprint, etc., personal authentication can be performed. In addition, the display unit 3504 may be provided with a backlight that emits near-infrared light or a sensor that emits near-infrared light. If a light source for imaging is used, it is also possible to image finger veins, palm veins, etc. The light-emitting device of one embodiment of the present invention may be applied to 54.

[0400] FIG. 11(C) shows a perspective view of a security light 3600. The light 3600 is The housing 3602 has a light 3608 on the outside, and the housing 3602 is equipped with a speaker 3610 and the like. The light-emitting element of one embodiment of the present invention can be used for the lighting 3608.

[0401] Light 3600 may include, for example, a device for grasping, holding, or holding light 3608. The inside of the housing 3602 is provided with a light 3600. The light emitting device may be provided with an electronic circuit that can control the light emitting method. Alternatively, the circuit may be one that can emit light intermittently multiple times, or the light emission current value may be controlled. The light intensity of the light emitted may be adjusted by the light source 3608. A circuit may be incorporated to output a loud alarm sound from speaker 3610.

[0402] 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 used to deter people with light or light and sound. The device may have a photographing function by being provided with a camera such as a still camera.

[0403] FIG. 12 shows an example in which the light-emitting element is used as an indoor lighting device 8501. Since the surface area can be increased, a large-area lighting device can be formed. By using a housing having the above structure, a lighting device 8502 having a curved light-emitting area can be formed. The light-emitting element shown in this embodiment mode has a thin film shape, and the housing can be designed with a high degree of freedom. Therefore, it is possible to create lighting devices with various elaborate designs. A large lighting device 8503 may be provided on the wall. A touch sensor may be provided in 503 to turn the power on or off.

[0404] In addition, by using light-emitting elements on the surface of the table, it has the function of a table. The lighting device 8504 can be used as a lighting device. This allows the lighting device to function as furniture.

[0405] In this manner, a lighting device and an electronic device can be obtained by applying the light-emitting device of one embodiment of the present invention. Note that the lighting devices and electronic devices to which the present invention can be applied are the same as those described in this embodiment. The present invention can be applied to electronic devices in a wide range of fields.

[0406] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. You can be there.

[0407] (Embodiment 8) In this embodiment mode, the light-emitting element described in any of Embodiments 1 to 4 is used as a lighting device. An example of this will be described with reference to FIG. 47. FIG. 47(B) is a top view of the lighting device, and FIG. 47(A) is a ) is a cross-sectional view taken along line ef in FIG. 47(B).

[0408] The lighting device in this embodiment is a light-transmitting substrate 4400 serving as a support, on which an anode The anode 4401 is the same as the electrode in any of the first to fourth embodiments. 101, 103 or anode 401. When light is extracted from the anode 4401 side, The anode 4401 is formed from a light-transmitting material.

[0409] A pad 4412 for supplying a voltage to the cathode 4404 is formed on the substrate 4400 .

[0410] An EL layer 4403 is formed on the anode 4401. The EL layer 4403 is the same as that of the first embodiment. The configuration of the EL layer in the fourth embodiment, the light-emitting units 106, 108, 110, and the light-emitting units For details on these configurations, please refer to the relevant descriptions.

[0411] A cathode 4404 is formed to cover the EL layer 4403. The cathode 4404 is formed as described in the first embodiment to the second embodiment. This corresponds to the electrode 102 or the cathode 402 in the fourth embodiment. When the cathode 4404 is formed from a highly reflective material, Voltage is supplied by connecting to the lead 4412.

[0412] As described above, the light emitting element having the anode 4401, the EL layer 4403, and the cathode 4404 is The light-emitting element has high luminous efficiency. The lighting device in the embodiment can be a lighting device with low power consumption.

[0413] The substrate 4400 on which the light emitting element having the above structure is formed and the sealing substrate 4407 are sealed. The lighting device is completed by fixing and sealing using materials 4405 and 4406. Either the inner sealing material 4405 or 4406 may be used. (not shown in Figure 47(B)) can be mixed with a desiccant, which absorbs moisture. This leads to improved reliability.

[0414] In addition, a part of the pad 4412 and the anode 4401 is extended outside the sealing materials 4405 and 4406. By providing a terminal on the converter, it can be used as an external input terminal. An IC chip 4420 or the like may be provided.

[0415] As described above, the lighting device described in this embodiment has the EL element according to any one of the first to fourth embodiments. The light-emitting device using the above light-emitting element can have low power consumption.

[0416] (Embodiment 9) In this embodiment mode, a light-emitting element including any of the light-emitting elements described in any of Embodiments 1 to 4 as a part thereof is used. An example of a child device will be described. The light emitting devices described in the first to fourth embodiments have a light emitting efficiency. As a result, the electronic device described in this embodiment has a high power consumption. It is possible to make the electronic device low in power consumption.

[0417] As an electronic device to which the light-emitting element is applied, for example, a television set (television or television) (also called revision receivers), monitors for computers, digital cameras, digital Video cameras, digital photo frames, mobile phones (also called mobile phones or mobile phone devices) ), portable game machines, personal digital assistants, audio playback devices, large game machines such as pachinko machines, etc. Specific examples of these electronic devices are listed below.

[0418] 48(A) shows an example of a television device. The television device has a housing 71 A display unit 7103 is built into the case 7101. The display unit 7103 can display images. The display portion 7103 may include any of the light-emitting elements described in Embodiments 1 to 4. These are arranged in a matrix.

[0419] The television device can be operated using the operation switches on the housing 7101 or a separate remote control. This can be done by the remote control device 7110. This allows you to control the channel and volume, and the image displayed on the display unit 7103 In addition, the remote control operation device 7110 can be operated. A display portion 7107 for displaying information output from the

[0420] The television device is assumed to be equipped with a receiver, modem, etc. It can receive television broadcasts and can also communicate by wire or wireless via a modem. By connecting to a network, you can send and receive data in one direction (sender to receiver) or two directions (sender to receiver). It is also possible to communicate information between the recipient and the receiver, or between receivers themselves.

[0421] FIG. 48(B1) shows a computer, which includes a main body 7201, a housing 7202, a display portion 7203, It includes a keyboard 7204, an external connection port 7205, a pointing device 7206, etc. Note that this computer uses the light-emitting element described in any of Embodiments 1 to 4 as a base. The display portion 7203 is fabricated by arranging the pixels in a pixel-like manner. The computer may be in the form shown in FIG. 48(B2). The keyboard 7204 and the pointing device 7206 are replaced by a second display unit. The second display portion 7210 is a touch panel type. The input display displayed on the display unit 7210 can be operated with a finger or a special pen. In addition, the second display portion 7210 can be used not only for input but also for other purposes. It is also possible to display an image. The display portion 7203 may also be a touch panel. The two screens are connected by a hinge, which prevents the screens from being damaged during storage or transport. This also prevents problems such as breakage and damage.

[0422] FIG. 48C shows an example of a portable terminal. The portable terminal is built in a housing 7401. In addition to the display unit 7402, operation buttons 7403, an external connection port 7404, a speaker 740 5, a microphone 7406, etc. The mobile terminal is the same as that of the first embodiment to the second embodiment. 7. The display portion 7402 has light-emitting elements described in Item 4 arranged in matrix.

[0423] The mobile terminal shown in FIG. 48C allows users to input information by touching the display portion 7402 with a finger or the like. In this case, the user can make a call or create an email. Such operations can be performed by touching the display portion 7402 with a finger or the like.

[0424] The screen of the display unit 7402 has three main modes. The first is a display mode that mainly displays images. The first mode is a display mode, and the second mode is an input mode that mainly inputs information such as characters. This is a display + input mode that combines two modes: display mode and input mode.

[0425] For example, when making a call or creating an email, the display unit 7402 is used to input characters. This is the main character input mode, and you can input characters displayed on the screen. It is preferable to display a keyboard or number buttons on most of the screen of the display portion 7402. I wish.

[0426] In addition, the mobile terminal may include a sensor for detecting tilt, such as a gyro or acceleration sensor. By providing a device, the orientation of the mobile terminal (portrait or landscape) can be determined and the screen display of the display portion 7402 can be displayed. The display can be switched automatically.

[0427] The screen mode can be switched by touching the display portion 7402 or by operating the housing 7401. This is done by operating the button 7403. Also, depending on the type of image displayed on the display unit 7402, For example, if the image signal to be displayed on the display unit is a video signal, If it is data, the display mode is switched to, and if it is text data, the input mode is switched to.

[0428] In the input mode, the optical sensor of the display unit 7402 detects a signal and displays it. If there is no input by touch operation on the part 7402 for a certain period of time, the screen mode is changed to the input mode. Alternatively, the display mode may be switched from the normal mode to the display mode.

[0429] The display portion 7402 can also function as an image sensor. By touching the device with your palm or fingers and capturing an image of your palm print or fingerprint, you can authenticate your identity. In addition, a backlight that emits near-infrared light to the display unit or a sensing light that emits near-infrared light By using a source, it is also possible to image finger veins, palm veins, etc.

[0430] Note that the structure described in this embodiment mode may be obtained by appropriately combining the structures described in any of Embodiment Modes 1 to 4. They can be used in combination.

[0431] As described above, a light emitting device including the light emitting device according to any one of the first to fourth embodiments is provided. The device has a very wide range of applications, and can be used in electronic devices in a wide range of fields. It is possible to use the light-emitting element described in any of Embodiments 1 to 4. As a result, an electronic device with low power consumption can be obtained.

[0432] FIG. 49(A) is a schematic diagram showing an example of a cleaning robot.

[0433] The cleaning robot 5100 has a display 5101 on the top surface and multiple The camera 5102, the brush 5103, and the operation button 5104 are also shown. However, the underside of the cleaning robot 5100 is provided with tires, a suction port, etc. The robot 5100 also has an infrared sensor, an ultrasonic sensor, an acceleration sensor, a piezo sensor, It is equipped with various sensors such as a sensor, a light sensor, and a gyro sensor. 100 is equipped with wireless communication means.

[0434] The cleaning robot 5100 moves by itself, detects the dust 5120, and sucks it out from the suction port on the bottom. It can suck up dirt.

[0435] In addition, the cleaning robot 5100 analyzes the image captured by the camera 5102 and detects the wall, furniture, or It can detect obstacles such as steps. Image analysis can also detect obstacles such as wiring. If an object that may get tangled in the brush 5103 is detected, the rotation of the brush 5103 can be stopped. can.

[0436] The display 5101 can display the remaining battery level and the amount of dust sucked. The route traveled by the cleaning robot 5100 can be displayed on the display 5101. In addition, the display 5101 is a touch panel, and the operation button 5104 is It may be provided in the ray 5101.

[0437] The cleaning robot 5100 can communicate with a portable electronic device 5140 such as a smartphone. The images captured by the camera 5102 can be displayed on the portable electronic device 5140. Therefore, the owner of the Cleaning Robot 5100 can check the status of the room even when he is away from home. In addition, the display on the display 5101 can be displayed on a mobile electronic device such as a smartphone. You can also check it out at.

[0438] The light-emitting device according to one embodiment of the present invention can be used for the display 5101 .

[0439] The robot 2100 shown in FIG. 49(B) includes a computing device 2110, an illuminance sensor 2101, a microphone, and a microphone array. A microphone 2102, an upper camera 2103, a speaker 2104, a display 2105, It is equipped with a lower camera 2106, an obstacle sensor 2107, and a movement mechanism 2108.

[0440] The microphone 2102 has a function of detecting the user's voice and environmental sounds. The speaker 2104 has a function of emitting sound. The device 2102 and the speaker 2104 can be used to communicate with the user. It is possible.

[0441] The display 2105 has the function of displaying various information. Any information desired by the user can be displayed on the display 2105. The display 2105 may be equipped with a touch panel. It may be an information terminal that can be charged by placing it in a fixed position on the robot 2100. and enables data transfer.

[0442] The upper camera 2103 and the lower camera 2106 are used to capture images of the surroundings of the robot 2100. The obstacle sensor 2107 detects the obstacles in the robot 210 by using the moving mechanism 2108. When moving forward, the robot can sense whether there are any obstacles in its path. 00 uses an upper camera 2103, a lower camera 2106, and an obstacle sensor 2107. It is possible to recognize the surrounding environment and move safely.

[0443] The light-emitting device according to one embodiment of the present invention can be used for the display 2105 .

[0444] Figure 49(C) is a diagram showing an example of a goggle-type display. Goggle-type display For example, the device includes a housing 5000, a display unit 5001, a speaker 5003, an LED lamp 5004, , connection terminal 5006, sensor 5007 (force, displacement, position, velocity, acceleration, angular velocity, rotation speed , distance, light, liquid, magnetic, temperature, chemical, sound, time, hardness, electric field, current, voltage, power, (including those that measure radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays), Microphone 5008, second display unit 5002, support unit 5012, earphone 5013, etc. Has.

[0445] The light-emitting device of one embodiment of the present invention can be used for the display portion 5001 and the second display portion 5002. can.

[0446] FIG. 50 shows a case where the light-emitting element according to any one of the first to fourth embodiments is used in a lighting device. The desk lamp shown in FIG. 50 has a housing 2001 and The light source 2002 may be the lighting device described in the eighth embodiment. good.

[0447] FIG. 51 shows a case where the light emitting element according to any one of the first to fourth embodiments is used as an indoor light source. This is an example of using the light source 3001 as the light source device 3001. The light-emitting element described herein has high light-emitting efficiency, and therefore can be used as a lighting device with low power consumption. In addition, the light-emitting element described in any of Embodiments 1 to 4 can Since the area can be increased, it can be used as a large-area lighting device. The light-emitting element described in any of Embodiments 1 to 4 is thin. It is possible to use it as a lighting device.

[0448] The light emitting device according to any one of the first to fourth embodiments is used as a front guard of an automobile. The present invention can be applied to a vehicle interior or a dashboard. 4. The light-emitting element according to any one of the preceding items is used in the windshield or dashboard of an automobile. The display areas 5200 to 5203 are the same as those in Embodiments 1 to 4. 10 is a display provided using the light-emitting element described in any one of the above.

[0449] In this embodiment, the display area 5200 and the display area 5201 are provided on the windshield of a car. The display device is equipped with the light-emitting element described in any one of Embodiments 1 to 4. The light-emitting element according to any one of the first to fourth embodiments has an anode and a cathode that are light-transmitting. By using electrodes that can be seen through to the other side, a so-called see-through display can be achieved. If the display is see-through, it can be installed on the windshield of a car. Even if the device is placed in a location, it can be installed without obstructing the view. When a transistor is provided, an organic transistor made of an organic semiconductor material or an oxide A light-transmitting transistor, such as a transistor using a semiconductor, is preferably used.

[0450] The display area 5202 is provided in the pillar portion. The display device is equipped with the light-emitting element described above. By projecting images from the imaging means, it is possible to complement the view blocked by the pillars. Similarly, the display area 5203 provided on the dashboard can be adjusted depending on the vehicle body. The view that is obstructed by the obstacle is cleared by projecting an image from an imaging device installed on the outside of the vehicle. This makes it possible to compensate for blind spots and increase safety. This allows the driver to check for safety more naturally and without any discomfort.

[0451] The display area 5203 also displays navigation information, speedometer and tachometer, mileage, fuel, gear status, etc. It can provide various information such as the status of the car, air conditioning settings, etc. The display items and layout can be changed as needed to suit your needs. can also be provided in the display areas 5200 to 5202. The display area 5203 can also be used as a lighting device.

[0452] 53(A) and (B) show a foldable mobile information terminal 5150. The foldable mobile information terminal 5150 includes a housing 5151, a display area 5152, and a bending portion 515 3. FIG. 53(A) shows the mobile information terminal 5150 in an unfolded state. Figure 5B) shows the mobile information terminal in a folded state. The mobile information terminal 5150 has a large display area. Despite having a range of 5152, it is compact and highly portable when folded.

[0453] The display area 5152 can be folded in half by the bend 5153. 3 is composed of an expandable member and multiple support members, and when folding, The bending portion 5153 has a curvature radius of 2 mm or more, preferably 3 mm or more. It can be folded.

[0454] The display area 5152 is a touch panel (input / output) equipped with a touch sensor (input device). The light-emitting device of one embodiment of the present invention can be used in the display region 5152. Cut.

[0455] 54(A) to 54(C) show a foldable mobile information terminal 9310. FIG. 54(A) shows the mobile information terminal 9310 in an unfolded state. FIG. 54(B) shows the mobile information terminal 9310 in an unfolded state. The mobile information terminal 9310 is shown in a state in which it is changing from one folded state to the other. FIG. 54(C) shows the portable information terminal 9310 in a folded state. The foldable design offers excellent portability and a seamless, large viewing area when unfolded. This provides excellent visibility of the display.

[0456] The display panel 9311 is supported by three housings 9315 connected by hinges 9313. The display panel 9311 is a touch panel equipped with a touch sensor (input device). The display panel 9311 may be a display panel (input / output device). The two housings 9315 are bent to open the mobile information terminal 9310. The light-emitting device of one embodiment of the present invention can be reversibly transformed from a folded state to a folded state. It can be used for a display panel 9311. A display area 931 in the display panel 9311 2 is a display area located on the side of the portable information terminal 9310 in the folded state. Area 9312 contains information icons and shortcuts to frequently used apps and programs. You can display the information and launch apps smoothly. do. [Example]

[0457] Example 1 In this example, a manufacturing example of a light-emitting element according to one embodiment of the present invention and characteristics of the light-emitting element were described. In addition, the refractive index of the organic compound used in the hole injection layer and the refractive index of the hole injection layer will be explained. A cross-sectional view of the device structure fabricated in this example is shown in FIG. are shown in Table 1. The structures and abbreviations of the compounds used are shown below.

[0458] [ka]

[0459] [Table 1]

[0460] [Table 2]

[0461] [Table 3]

[0462] <Refractive index measurement> The hole injection layer 111 of the light-emitting element 1 to the light-emitting element 4 and the comparative light-emitting element 5 to the comparative light-emitting element 16 The refractive indexes of the organic compound and the hole injection layer 111 were measured. At room temperature, a rotating compensator type multi-angle light velocity spectroscopic ellipsometer (M-2000U) was used. The measurement sample was prepared on a quartz substrate by vacuum deposition. and n Extra-ordinary were measured, and n average was calculated.

[0463] The results of measuring the refractive index of each film for light with a wavelength of 532 nm are shown in Figure 13. The TAPC used in the light-emitting elements 1 to 4 and the comparative light-emitting elements 9 to 12 was n O It was found that the refractive index of the organic compound was very low, with a refractive index of 1.70 or less. The comparative light-emitting elements 5 to 8 and the comparative light-emitting elements 13 to 16 were prepared using the DBT3P-II has a high refractive index with an n Ordinary of over 1.80. I found out that...

[0464] In addition, the hole injection layer 111 is required to have hole injection properties, so it is preferable that the layer contains an electron donating material. It is preferable that the hole injection layer of each light-emitting element uses MoO3, which has a high refractive index, as an electron donating material. 111 is expected to have a high refractive index. However, as shown in FIG. 13, the hole injection layer 1 The refractive index of the film in which MoO3 (11) was added to each organic compound was It was found that the refractive index of the hole injection layer 111 was slightly higher than that of the material. By using the refractive index of organic compounds as the electron donor, a material with a high refractive index can be used. It was found that a hole injection layer 111 with a low refractive index could be obtained even if the thickness was 100 nm.

[0465] 13, the hole injection layer 111 of each light emitting element has a thickness of n It was found that the difference between Ordinary and Extraordinary was small. The mixed film of MoO3, an electron donating material, and organic compounds has anisotropic was found to be less effective.

[0466] <Fabrication of light-emitting devices> <Fabrication of Light-Emitting Elements 1 to 4> On the substrate 200, an alloy of silver, palladium and copper (Ag-Pd-Cu, or APC) as the second anode (2) and the ITSO film with a thickness of 100 mm. The electrode 101 was formed by successively forming the ITSO film to thicknesses of 100 nm, 110 nm, and 110 nm. The APC film has a function of reflecting light and a function of transmitting light. The electrode area of ​​the electrode 101 is 4 mm 2 (2mm x 2mm). The refractive index (n Ordinary) of the ITSO film at 532 nm is 2.07 is.

[0467] Next, 1,1-bis(4-bis(2-methyl-1,1-bis-4-methyl-2-phenylene)) was deposited on the first electrode 101(2) as a hole injection layer 111. (4-methyl-phenyl)-amino-phenyl)-cyclohexane (abbreviation: TAPC) and MoO3 in a weight ratio (TAPC:MoO3) of 2:0.5 and a thickness of The value of x1 differs depending on the light-emitting element. The value of x1 in the optical element is shown in Table 3.

[0468] Next, a hole transport layer 112 was formed on the hole injection layer 111 by depositing PCCP to a thickness of 20 nm. The vapor deposition was carried out so that

[0469] Next, a first light-emitting layer 130(1) was formed on the hole transport layer 112 using 4,6mCzP2Pm PCCP and Ir(ppy)3 were mixed in a weight ratio of 4.6mCzP2Pm:PCCP:Ir (ppy)3) = 0.5:0.5:0.1 and the thickness was 20 nm. and then co-deposited with a second light-emitting layer 130(2) in a weight ratio of (4.6mCzP2Pm: PCCP:Ir(ppy)3) = 0.8:0.2:0.1, and the thickness was 20 The first light-emitting layer 130(1) and the second light-emitting layer 130(2) were co-deposited to a thickness of 100 nm. In (2), Ir(ppy)3 is the guest material that exhibits phosphorescence.

[0470] Next, a first electron transport layer 118(1) was formed on the second light-emitting layer 130(2). mCzP2Pm was vapor-deposited to a thickness of 20 nm. On the substrate 8(1), a second electron transport layer 118(2) was formed by depositing NBPhen to a thickness of 15 nm. Thus, it was evaporated.

[0471] Next, a lithium fluoride ( LiF) was evaporated to a thickness of 1 nm.

[0472] Next, on the electron injection layer 119, aluminum (Al) was deposited as the first electrode 102(1). Then, a second electrode was formed on the first electrode 102(1) to a thickness of 1 nm. As 102(2), Ag was vapor-deposited to a film thickness of 24 nm.

[0473] Next, DBT3P-II was deposited on the second electrode 102(2) to a thickness of 7 mm as a cap layer 145. The deposition was carried out so that the thickness was 0 nm.

[0474] Next, in a glove box with a nitrogen atmosphere, the device is sealed using an organic EL sealing material. The glass substrate for the organic material is fixed to the glass substrate on which the organic material is formed, and the light emitting element 1 is formed. The optical element 4 was sealed. Specifically, a glass substrate on which the organic material was formed was covered with a glass substrate. A sealing material is applied, and the substrate and a glass substrate for sealing are bonded together. of ultraviolet light at 6 J / cm 2 The light-emitting element was then irradiated with light and heat-treated at 80°C for 1 hour. Light-emitting devices 1 to 4 were obtained.

[0475] <Fabrication of Comparative Light-Emitting Elements 5 to 8> The manufacturing process of comparative light-emitting elements 5 to 8 is the same as the manufacturing process of light-emitting elements 1 to 4. Only the process for forming the hole injection layer 111 is different, and the other processes are performed in the same manner as in the light-emitting elements 1 to 4. It was.

[0476] On the electrode 101, a hole injection layer 111 was formed by mixing DBT3P-II and MoO3 in a weight ratio of ( The ratio of DBT3P-II:MoO3 was 2:0.5 and the thickness was 1 nm. The value of x1 differs depending on the light-emitting element. The values ​​are shown in Table 3.

[0477] <Fabrication of Comparative Light-Emitting Elements 9 to 12> The manufacturing process of comparative light-emitting elements 9 to 12 is the same as the manufacturing process of light-emitting elements 1 to 4. The only difference is the manufacturing process of the cap layer 145, and the other processes are the same as those of the light-emitting elements 1 to 4. went.

[0478] The comparative light-emitting elements 9 to 12 did not have the cap layer 145 formed thereon. After forming the electrode 102(2), sealing was performed to obtain the comparative light-emitting elements 9 to 12. Got it.

[0479] <Fabrication of Comparative Light-Emitting Elements 13 to 16> The manufacturing process of comparative light-emitting elements 13 to 16 is the same as that of comparative light-emitting elements 5 to 8. The only difference between the manufacturing process of the comparative light-emitting element 1 and the manufacturing process of the comparative light-emitting element 2 is the manufacturing process of the cap layer 145. The same procedure was carried out as for light-emitting element 8.

[0480] The comparative light-emitting elements 13 to 16 did not have the cap layer 145 formed thereon. After the electrode 102(2) is formed, sealing is performed to obtain the comparative light-emitting elements 13 to 1. I got a 6.

[0481] The light-emitting elements 1 to 4 and the comparative light-emitting elements 5 to 16 are top emitters. The light extraction side is the electrode 102 side.

[0482] <Light-emitting element characteristics> Next, the light-emitting elements 1 to 4 and the comparative light-emitting elements 5 to 16 fabricated above were The characteristics were measured. The luminance and CIE chromaticity were measured using a color luminance meter (Topcon, BM-5 A) was used to measure the electroluminescence spectrum, and a multichannel spectrometer (Hamamatsu Photonics) The measurement of each light-emitting element was carried out in an atmosphere maintained at room temperature (23°C). ) was performed.

[0483] Among the fabricated light-emitting elements, light-emitting element 1, comparative light-emitting element 5, comparative light-emitting element 9, and comparative light-emitting element 1 were selected. The current efficiency-luminance characteristics of the device 13 are shown in FIG. 14, and the current density-voltage characteristics are shown in FIG. The external quantum efficiency-luminance characteristics are shown in FIG. 16. As mentioned above, the hole injection layer 11 The light-emitting element 1 and the comparative light-emitting element 9 use TAPC, which has a low refractive index, as the organic compound of The light-emitting element 5 and the comparative light-emitting element 13 are elements using DBT3P-II. The light-emitting element 1 and the comparative light-emitting element 5 are light-emitting elements having a cap layer 145. The element 9 and the comparative light-emitting element 13 are light-emitting elements that do not have the cap layer 145. The device structure is the same except for the organic compound used in 111 and the presence or absence of the cap layer 145. be.

[0484] As can be seen from FIG. 15, the light-emitting element 1, the comparative light-emitting element 5, the comparative light-emitting element 9, and the comparative light-emitting element 13 have equivalent Therefore, it was found that the hole injection layer 111 has a current density-voltage characteristic of It was found that even when an organic compound with a low ionic strength was used, it had good hole injection properties.

[0485] 14 and 16, the light-emitting element 1, the comparative light-emitting element 5, the comparative light-emitting element 9, and the comparative light-emitting element 10 are The optical element 13 has a high current efficiency exceeding 100 cd / A and a high external quantum efficiency exceeding 20%. Furthermore, when the light-emitting element 1 and the comparative light-emitting element 9 were compared, The light-emitting element 1 has better current efficiency and external quantum efficiency. The comparative light-emitting element 9 has the cap layer 145, but the comparative light-emitting element 9 does not have the cap layer 145. Therefore, the light extraction efficiency is good. The comparative light-emitting element 5 and the light-emitting element 1 are more preferable than the comparative light-emitting element 1 in terms of current efficiency and external quantum efficiency. The relationship of the comparative light-emitting element 13 is similar.

[0486] Furthermore, the light-emitting element 1, the comparative light-emitting element 5, the comparative light-emitting element 9, and the comparative light-emitting element 13 were supplied with a current of 25 mA / cm 2 The emission spectrum when a current was applied at a current density of 1000 s is shown in FIG. The emission spectra of the light-emitting element 1, the comparative light-emitting element 5, the comparative light-emitting element 9, and the comparative light-emitting element 13 are The peaks are at 530 nm, 538 nm, 548 nm, and 556 nm, respectively. This is due to the emission of Ir(ppy)3, which is a guest material contained in the light-emitting layer 130. It was found that there were

[0487] Furthermore, the light-emitting elements 1 to 4 and the comparative light-emitting elements 5 to 16 have a 1000 cd / m 2 The device characteristics in this region are shown in Table 4.

[0488] [Table 4]

[0489] From the above results, it can be seen that the light-emitting elements 1 to 4 and the comparative light-emitting elements 5 to 6 fabricated in this example The optical element 16 exhibits good driving voltage and luminous efficiency regardless of the structure of the hole injection layer 111. Furthermore, it can be seen that the light-emitting elements 1 to 4 each having the cap layer 145 and the comparative light-emitting element Light emitting element 5 to comparative light emitting element 8 have better efficiency than comparative light emitting element 9 to comparative light emitting element 16 It can be seen that...

[0490] Furthermore, light-emitting elements 1 to 4 and comparative light-emitting elements 5 to 16 are guest It is believed that the material Ir(ppy)3 emits light. The peak wavelengths of the light emitted from the comparative light-emitting elements 5 to 16 are 530 nm as shown in FIG. The wavelength is considered to be about 580 nm to 590 nm. The optical element 9 to the comparative light-emitting element 12 are formed by the hole injection layer 111, which is a low refractive index layer, and the light-emitting layer 130. The optical distance is λ / 2 or less of the peak wavelength. Alternatively, the optical distance from the cathode (electrode 102) side to the electrode 101(2) is λ / 4±50 nm or more. The electrode 101 is located below the light-emitting layer 130, and the electrode 102 is located below the light-emitting layer 130. The optical distance from 101(2) to electrode 101(1) is 3λ / 4±50 nm or less.

[0491] <Relationship between Refractive Index of Hole Injection Layer 111 and External Quantum Efficiency> FIG. 18 shows the 1000 cd / m 2 External quantum in the vicinity The relationship between the efficiency and the emission peak wavelength obtained from each light-emitting element is shown in Figure 18. The data of the curve shows the values ​​of comparative light-emitting element 9 to comparative light-emitting element 12, The data for the curves used were the values ​​of comparative light-emitting elements 13 to 16, respectively.

[0492] 19 shows the 1000% luminance distribution of the light-emitting elements 1 to 4 and the comparative light-emitting elements 5 to 8. cd / m 2 Relationship between external quantum efficiency and peak emission wavelength obtained from each light-emitting device in the vicinity In FIG. 19, the data of the curve "TAPC" shows the values ​​of Light-emitting elements 1 to 4. The data for the DBT3P-II curve includes the values ​​of comparative light-emitting elements 5 to 8, respectively. It was used.

[0493] 18 and 19, the relationship between the external quantum efficiency and the peak wavelength is Within the range of the thickness of the interfacial layer 111, the external quantum efficiency tends to decrease as the peak wavelength increases. In the light-emitting device without the cap layer 145, the "TAP The curve data for "C" and "DBT3P-II" overlap, and the hole injection layer Regardless of the refractive index of 111, the efficiency is almost the same. For the light-emitting device with 145, the curve data for "TAPC" is better than "DBT3P-II" It can be seen that the data shows a better efficiency than the data of the curve of cap layer 14. In the light-emitting device having 5, by using a hole injection layer with a low refractive index, the luminous efficiency can be improved. It was found that it is possible to improve

[0494] Therefore, the hole injection layer 111 and the cap layer 112 having a low refractive index are used in the top-emission light-emitting element. It has been found that the use of the throttling layer 145 can improve efficiency. [Example]

[0495] In this example, a light-emitting element different from that in Example 1 was fabricated as a light-emitting element according to one aspect of the present invention. A manufacturing example and the characteristics of the light-emitting device are described below. The details of the device structure are shown in Table 5. The structures and abbreviations of the compounds are shown below. For other organic compounds, see Example 1 above. Just do that.

[0496] [ka]

[0497] [Table 5]

[0498] <Fabrication of Light-Emitting Element 17> APC and ITSO films were formed on the substrate 200 to thicknesses of 100 nm and 85 nm, respectively. By forming these layers in order, the electrode 101 was formed.

[0499] Next, a hole injection layer 111 was formed on the electrode 101 by depositing PCPPn and MoO3 in a weight ratio of (PCPPn:MoO3) is 2:0.5 and the thickness is 20 nm. Co-evaporation was carried out.

[0500] Next, a hole transport layer 112 was formed on the hole injection layer 111 by depositing PCPPn to a thickness of 30 nm. The vapor deposition was carried out as follows.

[0501] Next, a light-emitting layer 130 containing cgDBCzPA and N,N'-( Pyrene-1,6-diyl)bis[(6,N-diphenylbenzo[b]naphtho[1,2-d ]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03) in a weight ratio of (cgD BCzPA:1,6BnfAPrn-03) = 1:0.03, and the thickness is 2 The emitting layer 130 was formed by co-evaporation to a thickness of 5 nm. 03 is a guest material that emits blue fluorescence.

[0502] Next, on the light-emitting layer 130, a first electron transport layer 118(1) was formed using cgDBCzPA. The second electron transport layer 118(1) was deposited on the first electron transport layer 118(1) to a thickness of 5 nm. As the electron transport layer 118(2), BPhen was vapor deposited to a thickness of 5 nm.

[0503] Next, on the second electron transport layer 118(2), a layer of BPhen and Li was formed as the electron injection layer 119. F was added at a weight ratio of (BPhen:LiF) = 8:1 and the thickness was 15 nm. The film co-deposited with fluoride and organic compound has a higher refractive index than the film made of organic compound alone. Therefore, in the light-emitting element 17, the electron injection layer 119 is It functions as a electron injection layer and a low refractive index layer.

[0504] Next, on the electron injection layer 119, an electrode 102 was formed by depositing Ag and Mg in a weight ratio of (Ag:M The thickness was 25 nm and the thickness was 1:0.017.

[0505] Next, DBT3P-II was deposited on the electrode 102 to a thickness of 70 nm as a cap layer 145. It was evaporated like this.

[0506] Next, in a glove box with a nitrogen atmosphere, the device is sealed using an organic EL sealing material. The glass substrate for forming the light emitting element 17 is fixed to the glass substrate on which the organic material is formed. Specifically, a sealing material was applied around the organic material on the glass substrate on which the organic material was formed. The substrate was then attached to a glass substrate for sealing, and ultraviolet light with a wavelength of 365 nm was applied. 6J / cm 2 The light-emitting element 17 was obtained by the above steps. Ta.

[0507] <Preparation of Comparative Light-Emitting Element 18> The comparative light-emitting element 18 was fabricated by the same process as the light-emitting element 17 except for the electron transport layer 118(2) and The only difference was the process for forming the electron injection layer 119, and the other processes were the same as those in the light-emitting element 17.

[0508] For the comparative light-emitting element 18, BPhen was vapor-deposited to a thickness of 15 nm as the electron transport layer 118(2). Then, LiF was vapor deposited to a thickness of 1 nm as the electron injection layer 119 .

[0509] <Light-emitting element characteristics> Next, the characteristics of the fabricated light-emitting element 17 and comparative light-emitting element 18 were measured. The same procedure as in Example 1 was carried out.

[0510] FIG. 20 shows the current efficiency-luminance characteristics of the light-emitting element 17 and the comparative light-emitting element 18. The luminance-voltage characteristics are shown in Figure 21, and the external quantum efficiency-luminance characteristics are shown in Figure 22.

[0511] Furthermore, the light-emitting element 17 and the comparative light-emitting element 18 exhibited a luminance of 1000 cd / m 2Device characteristics in the vicinity is shown in Table 6.

[0512] [Table 6]

[0513] 21 and Table 6, the light-emitting element 17 and the comparative light-emitting element 18 have equivalent current density-voltage characteristics. I found out that I have it.

[0514] 20, 22, and Table 6, the light-emitting element 17 and the comparative light-emitting element 18 have good current efficiency. It was found that the low refractive index layer, BPhen, and The light-emitting element 17 having the LiF mixed film is different from the light-emitting element 17 having no mixed film, i.e., a low refractive index layer. It was found that the current efficiency and external quantum efficiency were better than those of the comparative light-emitting element 18 which does not have the Therefore, in the light-emitting device having the cap layer 145, the electron injection layer 11 having a low refractive index By using 9, the luminous efficiency can be improved.

[0515] Furthermore, the light-emitting element 17 and the comparative light-emitting element 18 were supplied with an electric current of 2.5 mA / cm 2 A current is passed with a current density of The emission spectra of the light-emitting element 17 and the comparative light-emitting element 18 are shown in FIG. The emission spectrum of the device 18 has a peak at about 457 nm. It was found that the emission originated from the guest material 1,6BnfAPrn-03. Here, the light emitting element 17 has an optical structure consisting of an electron injection layer 119, which is a low refractive index layer, and a light emitting layer 130. The distance from the light-emitting layer 130 to the electrode 101(2) is equal to or less than λ / 2 of the peak wavelength. The optical distance is λ / 4 or less, and the optical distance from the light-emitting layer 130 to the electrode 101(1) is 3λ / 4 or less. [Example]

[0516] In this example, a light-emitting element according to one embodiment of the present invention and a comparative light-emitting element different from those in the previous examples were fabricated. The cross-sectional view of the element structure manufactured in this example is shown in FIG. The details of the device structure are shown in Table 7. The structures of the compounds used are the same as those mentioned above. Please refer to the Examples and Modes of Carrying Out the Invention.

[0517] [Table 7]

[0518] <Fabrication of Light-Emitting Element 19> APC and ITSO films were formed on the substrate 200 to thicknesses of 100 nm and 85 nm, respectively. By forming these layers in order, the electrode 101 was formed.

[0519] Next, a hole injection layer 111 made of calcium fluoride (CaF2) and T APC and MoO3 were mixed in a weight ratio (CaF2:TAPC:MoO3) of 3:1:0.5. The hole injection layer 111 was co-evaporated so as to have a thickness of 35 nm. Next, PCPPn and MoO3 were mixed in a weight ratio of (PCPPn:Mo O3) was co-deposited at a ratio of 2:0.5 to a thickness of 5 nm.

[0520] Next, a hole transport layer 112 was formed on the hole injection layer 111 by depositing PCPPn to a thickness of 10 nm. The vapor deposition was carried out as follows.

[0521] Next, a light-emitting layer 130 containing cgDBCzPA and 1,6Bnf The weight ratio of APrn-03 to (cgDBCzPA:1,6BnfAPrn-03) = 1: The light-emitting layer 13 was co-deposited so that the thickness of the layer became 0.03 and the thickness became 25 nm. In 0, 1,6BnfAPrn-03 is a guest material that exhibits blue fluorescent emission.

[0522] Next, on the light-emitting layer 130, NBPhen was deposited to a thickness of 5 nm as the electron transport layer 118. The vapor deposition was carried out so that

[0523] Next, on the electron transport layer 118, an electron injection layer 119 containing BPhen and LiF in a weight ratio of Co-evaporation was carried out so that the ratio of BPhen to LiF was 8:1 and the thickness was 30 nm. The electron injection layer 119 functions as a low refractive index layer.

[0524] Next, Ag and magnesium (Mg) were laminated on the electron injection layer 119 as the electrode 102. The thickness was 15 nm and the ratio of Ag to Mg was 1:0.017. Successful.

[0525] Next, DBT3P-II was deposited on the electrode 102 to a thickness of 70 nm as a cap layer 145. It was evaporated like this.

[0526] Next, in a glove box with a nitrogen atmosphere, the device is sealed using an organic EL sealing material. The glass substrate for forming the light emitting element 19 is fixed to the glass substrate on which the organic material is formed. Specifically, a sealing material was applied around the organic material on the glass substrate on which the organic material was formed. The substrate was then attached to a glass substrate for sealing, and ultraviolet light with a wavelength of 365 nm was applied. 6J / cm 2 The light-emitting element 19 was obtained by the above steps. Ta.

[0527] <Fabrication of Comparative Light-Emitting Element 20> Comparative light-emitting element 20 was fabricated as a comparison with light-emitting element 19. Comparative light-emitting element 20 was fabricated using a hole injection The layer 111 and the electron injection layer 119 do not function as low refractive index layers.

[0528] APC and ITSO films were formed on the substrate 200 to thicknesses of 100 nm and 85 nm, respectively. By forming these layers in order, the electrode 101 was formed.

[0529] Next, a hole injection layer 111 was formed on the electrode 101 by depositing PCPPn and MoO3 in a weight ratio of Co-evaporation was performed to a thickness of 35 nm with a ratio of (PCPPn:MoO3) of 2:1. I arrived.

[0530] Next, a hole transport layer 112 was formed on the hole injection layer 111 by depositing PCPPn to a thickness of 10 nm. The vapor deposition was carried out as follows.

[0531] Next, a light-emitting layer 130 containing cgDBCzPA and 1,6Bnf The weight ratio of APrn-03 to (cgDBCzPA:1,6BnfAPrn-03) = 1: The film was co-evaporated to a thickness of 25 nm and a thickness of 0.03.

[0532] Next, on the light-emitting layer 130, NBPhen was deposited to a thickness of 25 nm as the electron transport layer 118. The vapor deposition was carried out as follows.

[0533] Next, LiF was deposited on the electron transport layer 118 to form the electron injection layer 119 to a thickness of 1 nm. Subsequently, an electrode 102 made of Ag and magnesium was deposited on the electron injection layer 119. (Mg) so that the weight ratio of (Ag:Mg) is 1:0.017 and the thickness is 15 nm It was formed so that

[0534] Next, DBT3P-II was deposited on the electrode 102 to a thickness of 70 nm as a cap layer 145. It was evaporated like this.

[0535] Next, in a glove box with a nitrogen atmosphere, the device is sealed using an organic EL sealing material. By fixing the glass substrate for the organic material to the glass substrate on which the organic material was formed, comparative light-emitting element 2 Specifically, a sealing material was applied around the organic material on the glass substrate on which the organic material was formed. The substrate is then bonded to a glass substrate for sealing, and ultraviolet light with a wavelength of 365 nm is applied. Light at 6J / cm 2 The light-emitting element was irradiated with light and then heat-treated at 80° C. for 1 hour. I got 20.

[0536] <Light-emitting element characteristics> Next, the characteristics of the fabricated light-emitting element 19 and the comparative light-emitting element 20 were measured. The CIE chromaticity was measured using a spectroradiometer (Topcon, SR-UL1R) and an electric field A multichannel spectrometer (Hamamatsu Photonics, PMA-11) was used to measure the optical spectrum. The measurements of each light-emitting device were carried out at room temperature (in an atmosphere maintained at 23°C).

[0537] FIG. 24 shows the current efficiency-luminance characteristics of the light-emitting element 19 and the comparative light-emitting element 20. The photoelectric efficiency-luminance characteristics are shown in FIG.

[0538] Furthermore, the light-emitting element 19 and the comparative light-emitting element 20 exhibited a luminance of 1000 cd / m 2 Device characteristics in the vicinity is shown in Table 8.

[0539] [Table 8]

[0540] 24, 25 and Table 8, the light-emitting element 19 and the comparative light-emitting element 20 have good current efficiency. It was found that the light-emitting element 1 having a low refractive index layer had a high efficiency and external quantum efficiency. The light-emitting element 9 has better current efficiency and external quantum efficiency than the comparative light-emitting element 20, which does not have a low refractive index layer. Therefore, in the light emitting device having the cap layer 145, a low refractive index can be obtained. By using a refractive index layer, the luminous efficiency can be improved.

[0541] Furthermore, the light-emitting element 19 and the comparative light-emitting element 20 were supplied with an electric current of 2.5 mA / cm 2 A current is passed with a current density of The emission spectra of the light-emitting element 19 and the comparative light-emitting element 20 are shown in FIG. The emission spectrum of the device 20 has a peak at about 457 nm. It was found that the emission originated from the guest material 1,6BnfAPrn-03. 26 and Table 8, the emission spectra of the light-emitting element 19 and the comparative light-emitting element 20 are They are nearly identical and have nearly the same chromaticity. [Example]

[0542] Example 1 This example describes a manufacturing example of a light-emitting element according to one embodiment of the present invention, which is different from the previous example, and the light-emitting element The cross-sectional view of the device structure fabricated in this example is the same as that shown in FIG. The details of the molecular structure are shown in Table 9. The structures and abbreviations of the compounds used are shown below. For the organic compounds, the above examples and embodiments may be referred to.

[0543] [ka]

[0544] [Table 9]

[0545] <Fabrication of light-emitting element 21> APC and ITSO films were formed on the substrate 200 to thicknesses of 100 nm and 85 nm, respectively. By forming these layers in order, the electrode 101 was formed.

[0546] Next, a hole injection layer 111 made of calcium fluoride (CaF2) and T APC and MoO3 were mixed in a weight ratio (CaF2:TAPC:MoO3) of 3:1:0.5. The hole injection layer 111 was co-evaporated so as to have a thickness of 30 nm. Next, PCPPn and MoO3 were mixed in a weight ratio of (PCPPn:Mo O3) was co-deposited at a ratio of 2:0.5 to a thickness of 5 nm.

[0547] Next, a hole transport layer 112 was formed on the hole injection layer 111 by depositing PCPPn to a thickness of 10 nm. The vapor deposition was carried out as follows.

[0548] Next, a light-emitting layer 130 containing cgDBCzPA and 3,10-bis(3,10-dichloro-2,3,4-triazabicyclo[4,5,6,7,8]phenyl)-3,4-triazabicyclo[4,5,6,7,8]phenyl-2, ... bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6 ,7-b']bisbenzofuran (abbreviation: 3,10FrA2Nbf(IV)-02) The ratio of cgDBCzPA:3,10FrA2Nbf(IV)-02 was 1:0.01. The co-deposition was carried out so that the thickness of the light-emitting layer 130 was 25 nm. , 3,10FrA2Nbf(IV)-02 is the guest material that exhibits blue fluorescent emission.

[0549] Next, on the light-emitting layer 130, NBPhen was deposited to a thickness of 5 nm as the electron transport layer 118. The vapor deposition was carried out so that

[0550] Next, on the electron transport layer 118, an electron injection layer 119 containing BPhen and LiF in a weight ratio of Co-evaporation was carried out so that the ratio of BPhen to LiF was 8:1 and the thickness was 25 nm. The electron injection layer 119 functions as a low refractive index layer.

[0551] Next, Ag and magnesium (Mg) were laminated on the electron injection layer 119 as the electrode 102. The thickness was 15 nm and the ratio of Ag to Mg was 1:0.017. Successful.

[0552] Next, DBT3P-II was deposited on the electrode 102 to a thickness of 70 nm as a cap layer 145. It was evaporated like this.

[0553] Next, in a glove box with a nitrogen atmosphere, the device is sealed using an organic EL sealing material. The glass substrate for forming the light emitting element 21 is fixed to the glass substrate on which the organic material is formed. Specifically, a sealing material was applied around the organic material on the glass substrate on which the organic material was formed. The substrate was then attached to a glass substrate for sealing, and ultraviolet light with a wavelength of 365 nm was applied. 6J / cm 2 The light-emitting element 21 was obtained by the above steps. Ta.

[0554] <Light-emitting element characteristics> Next, the characteristics of the fabricated light-emitting element 21 were measured. A spectroradiometer (Topcon, SR-UL1R) was used to measure the electroluminescence spectrum. A multi-channel spectrometer (Hamamatsu Photonics, PMA-11) was used. The device was measured at room temperature (in an atmosphere maintained at 23°C).

[0555] The current efficiency-luminance characteristics of the light-emitting element 21 are shown in FIG. 27, the current density-voltage characteristics in FIG. 28, and the external The photoelectric efficiency-luminance characteristics are shown in FIG.

[0556] In addition, the light emitting element 21 has a luminance of 1000 cd / m 2 The device characteristics in this region are shown in Table 10.

[0557] [Table 10]

[0558] In addition, the light emitting element 21 is supplied with 2.5 mA / cm 2 Emission spectrum when current is applied at a current density of As shown in FIG. 30, the emission spectrum of the light-emitting element 21 has a peak at 452 nm. The peak had a half-width of 22 nm. This is due to the fluorescence emission of the guest material, 3,10FrA2Nbf(IV)-02. I found out that...

[0559] 27, 29, and Table 10, the light-emitting element 21 exhibited excellent current efficiency and external capacitance. The light emitting element 21 is a fluorescent light emitting element, and has low visibility. Despite emitting light in the region, the current efficiency is extremely high at approximately 7.5 cd / A. Therefore, in a light emitting device having a cap layer 145, a low refractive index layer is used. By doing so, the light emitting efficiency can be improved. The optical path from the light-emitting layer 130 to the electrode 101(1) is λ / 4 or less. The optical path length is 3λ / 4 or less. (Reference example)

[0560] In this reference example, the synthesis method of 3,10FrA2Nbf(IV)-02 used in the light-emitting device 21 This article explains:

[0561] Step 1: 3,7-bis(4-chloro-2-fluorophenyl)-2,6-dimethoxamine Synthesis of sinaphthalene> In a 500 mL three-neck flask, add 11 g (24 mmol) of 3,7-diiodo-2,6-dimethicone. xynaphthalene and 14 g (78 mmol) of 4-chloro-2-fluorophenylboron Acid, 22 g (0.16 mol) potassium carbonate, and 0.74 g (2.4 mmol) To this mixture was added 120 mL of toluene. The mixture was degassed by stirring under reduced pressure. (0.49 mmol) of palladium(II) acetate was added, and the mixture was heated at 110°C for 50 minutes under a nitrogen stream. The mixture was stirred for 5 hours.

[0562] After stirring, toluene was added to the mixture, and Florisil (Wako Pure Chemical Industries, Ltd., catalogue) was added. No.: 540-00135), Celite (Wako Pure Chemical Industries, Ltd., Catalog No.: 531 The filtrate was concentrated to give a solid. .

[0563] The obtained solid was purified by silica gel column chromatography (developing solvent: toluene:hexane = The resulting solid was recrystallized with ethyl acetate to give 5.7 g of a white solid in a yield of 1:1. The synthesis scheme for Step 1 is shown below.

[0564] [ka]

[0565] The obtained solid 1 The 1 H NMR data is shown in FIG. 31, and the numerical data is shown below. 1 H NMR(CDCl3,300MHz):δ=3.88(s,6H),7.18-7 .24(m,6H),7.37(t,J1=7.2Hz,2H),7.65(s,2H) .

[0566] Step 2: 3,7-bis(4-chloro-2-fluorophenyl)-2,6-dihydro Synthesis of xynaphthalene In a 200 mL three-neck flask, add 5.7 g (13 mmol) of 3,7-bis(4-chloro-2- (fluorophenyl)-2,6-dimethoxynaphthalene was placed in the flask, and the atmosphere in the flask was replaced with nitrogen. To this flask was added 32 mL of dichloromethane. To this solution was added 28 mL (28 mmol) of l) Boron tribromide (approximately 1.0 mol / L dichloromethane solution) and 20 mL of dichloromethane After the addition was completed, the solution was stirred at room temperature.

[0567] After stirring, about 20 mL of water was added to the solution under ice cooling and stirred. The aqueous layer was separated and extracted with dichloromethane and ethyl acetate. The organic layer was washed with saturated saline and saturated aqueous sodium bicarbonate. After drying, the mixture was gravity filtered. The obtained filtrate was concentrated. The synthesis scheme for Step 2 is shown below.

[0568] [ka]

[0569] The obtained solid 1The 1 H NMR data is shown in FIG. 32, and the numerical data is shown below. 1 H NMR(DMSO-d6,300MHz):δ=7.20(s,2H),7.37 (dd,J1=8.4Hz,J2=1.8Hz,2H),7.46-7.52(m,4H ),7.59(s,2H),9.71(s,2H).

[0570] Step 3: 3,10-dichloronaphtho[2,3-b;6,7-b']bisbenzofura Synthesis of amine In a 200 mL three-neck flask, 5.4 g (13 mmol) of 3,7-bis(4-chloro-2 -fluorophenyl)-2,6-dihydroxynaphthalene and 7.1 g (52 mmol) Potassium carbonate was added to the mixture. 130 mL of N-methyl-2-pyrrolidone was added. The mixture was degassed by stirring under reduced pressure. After degassing, the mixture was stirred under a nitrogen stream. The mixture was stirred at 120° C. for 7 hours. After stirring, water was added to the mixture, and the precipitated solid was collected by filtration. This solid was washed with water and ethanol. Ethanol was added to the obtained solid, and after heating and stirring, Ethyl acetate was added to the resulting solid, and after heating and stirring, the mixture was filtered to give a pale yellow solid. The compound was obtained in an amount of 4.5 g and a yield of 92%. The synthetic scheme for Step 3 is shown below.

[0571] [ka]

[0572] The obtained solid 1 The 1 H NMR data is shown in FIG. 33, and the numerical data is shown below. 1 H NMR(1,1,2,2-Tetrachloroethane-D2,300M Hz):δ=7.44(dd,J1=8.1Hz,J2=1.5Hz,2H),7.65 (d,J1=1.8Hz,2H),8.05(d,J1=8.4Hz,2H),8.14 (s,2H),8.52(s,2H).

[0573] Step 4: 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamine] 3,10FrA2N Synthesis of bf(IV)-O2 In a 200 mL three-neck flask, add 1.2 g (3.0 mmol) of 3,10-dichloronaphtho[2 ,3-b;6,7-b']bisbenzofuran and 2.0 g (7.7 mmol) of N-(dibenzofuran benzofuran-3-yl)-N-phenylamine, 0.11 g (0.30 mmol) (1-Adamantyl)-n-butylphosphine, 1.8 g (18 mmol) of sodium tert-butoxide was added to the mixture. 30 mL of xylene was added to the mixture. The mixture was degassed by stirring under reduced pressure. Bis(dibenzylideneacetone)palladium(0) was added, and the mixture was heated at 150°C under a nitrogen stream for 32 minutes. The mixture was stirred for 1 hour.

[0574] After stirring, toluene and water were added to the mixture, and the mixture was subjected to suction filtration to obtain a solid. The mixture was filtered through Florisil, Celite, and alumina to obtain a filtrate. The filtrate was concentrated to give a solid. This solid was purified by silica gel column chromatography ( The solid was recrystallized three times with toluene to give a yellow solid. A white solid was obtained in 1.8 g, 71% yield.

[0575] The obtained solid (1.2 g) was purified by train sublimation. Pressure 2.3 x 10-2 The temperature was increased to 380°C under the conditions of 0 Pa and 0 mL / min argon flow rate. After sublimation purification, 1.0 g of a yellow solid was obtained with a recovery rate of 88%. The synthesis scheme is shown below.

[0576] [ka]

[0577] The obtained solid 1 The H NMR data is shown in Figure 34, and the numerical data is shown below. In this synthesis example, 3,10FrA2Nbf(IV), an organic compound according to one embodiment of the present invention, It was found that -02...

Claims

1. A light-emitting device having a first electrode, a first layer, a light-emitting layer, a second electrode, and a second layer, the first layer is provided between the first electrode and the light-emitting layer, the light-emitting layer is provided between the first layer and the second electrode, the second electrode is provided between the light-emitting layer and the second layer, the first layer includes a first organic compound and a compound having a halogen group or a cyano group, the second layer comprises a second organic compound; the first organic compound includes an aromatic ring having a t-butyl group; the refractive index of the film formed using the first organic compound is 1.80 or less; the second electrode is light-transmitting and includes a first material; a film formed using the second organic compound has a refractive index higher than a refractive index of a film formed using the first material;

2. A light-emitting device having a first electrode, a first layer, a light-emitting layer, a second electrode, and a second layer, the first layer is provided between the first electrode and the light-emitting layer, the light-emitting layer is provided between the first layer and the second electrode, the second electrode is provided between the light-emitting layer and the second layer, the first layer includes a first organic compound and a compound having a halogen group or a cyano group, the second layer comprises a second organic compound; the first organic compound includes an aromatic ring having a t-butyl group; the film formed using the first organic compound has an ordinary ray refractive index of 1.80 or less at a wavelength of 532 nm; A light-emitting device, wherein the film formed using the second organic compound has an ordinary refractive index of higher than 1.80 at a wavelength of 532 nm.

3. A light-emitting device having a first electrode, a first layer, a light-emitting layer, a second electrode, and a second layer, the first layer is provided between the first electrode and the light-emitting layer, the light-emitting layer is provided between the first layer and the second electrode, the second electrode is provided between the light-emitting layer and the second layer, the first layer comprises a first organic compound; the second layer comprises a second organic compound; the first organic compound includes an aromatic ring having a t-butyl group; A light-emitting device, wherein the refractive index of the film formed using the first organic compound is 1.80 or less.

4. In claim 1 or claim 2, a difference between the refractive index of ordinary rays and the refractive index of extraordinary rays in a mixed film formed using the first organic compound and the compound is smaller than a difference between the refractive index of ordinary rays and the refractive index of extraordinary rays in a film formed using the first organic compound.

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