Light-emitting device

Abstract

To provide a light-emitting element including a plurality of light-emitting layers between a pair of electrodes, in each light-emitting layer of which the driving voltage is low and the luminous efficiency is high.SOLUTION: A light-emitting element includes a first light-emitting layer to a third light-emitting layer between a cathode and an anode. The first light-emitting layer includes a first phosphorescent material and a first electron-transporting material. The second light-emitting layer includes a second phosphorescent material and a second electron-transporting material. The third light-emitting layer includes a fluorescent material and a third electron-transporting material. The first light-emitting layer to the third light-emitting layer are provided in contact with an electron-transporting layer provided on a cathode side. The triplet excitation energy level of the material that forms the electron-transporting layer is lower than the triplet excitation energy level of the first electron-transporting material and the second electron-transporting material.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] One aspect of the present invention relates to a light-emitting device in which a light-emitting layer that emits light by applying an electric field is sandwiched between a pair of electrodes, a light-emitting device having such a light-emitting device, an electronic device, and a lighting device.

Background Art

[0002] A light-emitting device using an organic compound having characteristics such as thinness, light weight, high-speed response, and driving at a low DC voltage as a light-emitting layer is expected to be applied to next-generation flat panel displays. In particular, a display device in which light-emitting devices are arranged in a matrix is considered to have an advantage in that it has a wider viewing angle and better visibility compared to a conventional liquid crystal display device.

[0003] The light-emitting mechanism of a light-emitting device is as follows: when a voltage is applied across a light-emitting layer containing a light-emitting substance between a pair of electrodes, electrons injected from the cathode and holes injected from the anode recombine at the light-emitting center of the light-emitting layer to form molecular excitons, and when the molecular excitons relax to the ground state, they emit energy and light. It is known that there are a singlet excited state and a triplet excited state in the excited state, and it is considered that light emission can occur through either excited state. Light emission from the singlet excited state (S * ) is called fluorescence, and light emission from the triplet excited state (T * ) is called phosphorescence.

[0004]

[0005]

[0005] As one of the full-colorization methods, for example, there is a method of separately coating the light-emitting layer for each pixel. . The light-emitting layer is vapor-deposited only on the necessary pixels using a shadow mask. In this case, in order to reduce the number of processes and cut costs, a configuration is disclosed in which layers other than the light-emitting layer, for example, a hole transport layer, an electron transport layer, and a cathode are commonly formed for a plurality of pixels (see Patent Document 1).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] In the case of the configuration described in Patent Document 1, since the hole transport layer or the electron transport layer is commonly used for a plurality of pixels, element characteristics such as drive voltage differ for each pixel that displays a different color. In addition, in such a configuration, since the hole transport layer or the electron transport layer is common for pixels that display different colors, the optimal element configuration is not achieved for each pixel, and in at least one of the plurality of pixels, there is a problem that abnormalities in element characteristics, such as an increase in drive voltage or a decrease in reliability, occur. In view of the above problems, in one aspect of the present invention, a light-emitting element having a plurality of light-emitting layers between a pair of electrodes, in each of the plurality of light-emitting layers, a light-emitting element having a low drive voltage and a high luminous efficiency is provided as one of the objects.

[0008] In view of the above-described problems, in one aspect of the present invention, a light-emitting element having a plurality of light-emitting layers between a pair of electrodes is provided, and in each of the plurality of light-emitting layers, a light-emitting element having a low drive voltage and a high luminous efficiency is provided as one of the objects. element having a low drive voltage and a high luminous efficiency is provided as one of the objects. element having a low drive voltage and a high luminous efficiency is provided as one of the objects.

Means for Solving the Problems

[0009] One aspect of the present invention is a light-emitting element including a first light-emitting layer to a third light-emitting layer between a cathode and an anode, wherein the first light-emitting layer has a first phosphorescent material and a first electron transporting material, the second light-emitting layer has a second phosphorescent material and a second electron transporting material, and the third light-emitting layer has a fluorescent material and a third electron transporting material, and the first light-emitting layer to the third light-emitting layer are each provided in contact with an electron transporting layer disposed on the cathode side, and the material forming the electron transporting layer has a triplet excitation energy level lower than the triplet excitation energy levels of the first electron transporting material and the second electron transporting material. This is a light-emitting element characterized in that.

[0010] By adopting such a configuration in which the electron transporting layer is commonly in contact with the first to third light-emitting layers, the productivity during the formation of the light-emitting element can be improved. Further, the electron transporting layer is formed of a material having a triplet excitation energy level (T1 level) lower than the triplet excitation energy levels (T1 levels) of the first electron transporting material and the second electron transporting material. Since the electron transporting properties of the first electron transporting material and the second electron transporting material are high, the light-emitting region of the light-emitting element according to one aspect of the present invention is formed on the hole transporting layer side of the light-emitting layer. Therefore, the first light-emitting layer and the second light-emitting layer are not affected by the low T1 level of the electron transporting layer, and the element configuration has a low driving voltage and high luminous efficiency. Also, another aspect of the present invention is a light-emitting element including a first light-emitting layer to a third light-emitting layer between a cathode and an anode, wherein the first light-emitting layer has a first phosphorescent material and a first electron transporting material, the second light-emitting layer has a second phosphorescent material and a second electron transporting material, the third light-emitting layer has a fluorescent material and a third electron transporting material, and the first light-emitting layer and the second And the first light-emitting layer and the second light-emitting layer are not affected by the low T1 level of the electron transporting layer, resulting in a low driving voltage and high luminous efficiency.

[0011] Moreover, another aspect of the present invention is a light-emitting element including a first light-emitting layer to a third light-emitting layer between a cathode and an anode, wherein the first light-emitting layer has a first phosphorescent material and a first electron transporting material, the second light-emitting layer has a second phosphorescent material and a second electron transporting material, and the third light-emitting layer has a fluorescent material and a third electron transporting material, and the first light-emitting layer and the second It is provided in contact with the cathode side of the light-emitting layer, and the triplet excitation energy level of the third electron-transporting material is lower than the triplet excitation energy levels of the first electron-transporting material and the second electron-transporting material This is a light-emitting element characterized by this.

[0012] In this way, the third light-emitting layer is provided in contact with the cathode sides of the first light-emitting layer and the second light-emitting layer By doing this, the third light-emitting layer functions as an electron-transporting layer on the first light-emitting layer and the second light-emitting layer and functions as a light-emitting layer in the third light-emitting layer. Note that the fluorescent material (also referred to as a dopant or guest material) contained in the third light-emitting layer does not contribute to light emission on the first light-emitting layer and the second light-emitting layer because the electron-transporting properties of the first electron-transporting material and the second electron-transporting material are high. On the other hand, in the third light-emitting layer, light emission from the fluorescent material can be obtained . That is, since the third light-emitting layer simultaneously has the functions of an electron-transporting layer and a light-emitting layer, it can be commonly used as an electron-transporting layer on the first light-emitting layer and the second light-emitting layer, and can be used as a light-emitting layer in the third light-emitting layer. Therefore, the productivity during the formation of the light-emitting element can be improved.

[0013] In addition, one aspect of the present invention also includes a light-emitting device having a light-emitting element, an electronic device having the light-emitting device, and a lighting device in the category. Therefore, the light-emitting device in this specification refers to an image display device or a light source (including a lighting device). Also, a connector is attached to the light-emitting device, for example, an FPC (Flexible printed circuit) or a TCP (Tape Carrier Package), a module with a printed wiring board provided in front of the TCP , or a COG (Chip On​​ Modules in which an IC (integrated circuit) is directly mounted by the Glass method are also all included in the light-emitting device shall be included.

Advantages of the Invention

[0014] A light-emitting element according to one aspect of the present invention is a light-emitting element having a plurality of light-emitting layers between a pair of electrodes such that, in each of the plurality of light-emitting layers, a light-emitting element with a low driving voltage and high luminous efficiency can be provided. Further, it is possible to improve the productivity when forming the light-emitting element can be achieved.

Brief Description of the Drawings

[0015]

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Embodiments for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and its form and details without departing from the spirit and scope of the present invention It is possible to make various changes. Therefore, the present invention should not be construed as being limited to the descriptions of the embodiments shown below. It is not limited to the content.

[0017] Note that the positions, sizes, ranges, etc. of the respective components shown in the drawings and the like may not represent the actual positions, sizes, ranges, etc. for the sake of easy understanding. For this reason, the disclosed invention is not necessarily limited to the positions, sizes, ranges, etc. disclosed in the drawings and the like. Note that the ordinal numbers such as "first", "second", "third", etc. in this specification and the like are added to avoid confusion of the components, and it is noted that they are not numerically limiting. It is not necessarily limited to the positions, sizes, ranges, etc. disclosed in the drawings and the like.

[0018] Note that the ordinal numbers such as "first", "second", "third", etc. in this specification and the like are added to avoid confusion of the components, and it is noted that they are not numerically limiting. It is added to avoid confusion of the components, and it is noted that they are not numerically limiting.

[0019] (Embodiment 1) In this embodiment, the concept and specific configuration of a light-emitting element, which is one aspect of the present invention, will be described. First, the light-emitting element, which is one aspect of the present invention, will be described with reference to FIGS. 1(A) and (B). First, regarding the light-emitting element which is one aspect of the present invention, it will be described with reference to FIGS. 1(A) and (B). First, regarding the light-emitting element which is one aspect of the present invention, it will be described with reference to FIGS. 1(A) and (B).

[0020] The light-emitting element shown in FIG. 1(A) has a light-emitting layer 115 between a pair of electrodes (anode 101 and cathode 103). The light-emitting layer 115 includes a first phosphorescent material 121a and a first electron-transporting material 122a in a first light-emitting layer 115a, a second phosphorescent material 131a and a second electron-transporting material 132a in a second light-emitting layer 115b, and a fluorescent material 141a and a third electron-transporting material 142a in a third light-emitting layer 115c. The light-emitting layer 115 includes a first light-emitting layer 115a containing a first phosphorescent material 121a and a first electron-transporting material 122a, a second light-emitting layer 115b containing a second phosphorescent material 131a and a second electron-transporting material 132a, and a third light-emitting layer 115c containing a fluorescent material 141a and a third electron-transporting material 142a. The light-emitting layer 115 includes a first light-emitting layer 115a containing a first phosphorescent material 121a and a first electron-transporting material 122a, a second light-emitting layer 115b containing a second phosphorescent material 131a and a second electron-transporting material 132a, and a third light-emitting layer 115c containing a fluorescent material 141a and a third electron-transporting material 142a. The light-emitting layer 115 includes a first light-emitting layer 115a containing a first phosphorescent material 121a and a first electron-transporting material 122a, a second light-emitting layer 115b containing a second phosphorescent material 131a and a second electron-transporting material 132a, and a third light-emitting layer 115c containing a fluorescent material 141a and a third electron-transporting material 142a. The light-emitting layer 115 includes a first light-emitting layer 115a containing a first phosphorescent material 121a and a first electron-transporting material 122a, a second light-emitting layer 115b containing a second phosphorescent material 131a and a second electron-transporting material 132a, and a third light-emitting layer 115c containing a fluorescent material 141a and a third electron-transporting material 142a.

[0021] Also, each of the first light-emitting layer 115a, the second light-emitting layer 115b, and the third light-emitting layer 115c is provided in contact with an electron-transporting layer 117 disposed on the cathode 103 side. Each of the first light-emitting layer 115a, the second light-emitting layer 115b, and the third light-emitting layer 115c is provided in contact with an electron-transporting layer 117 disposed on the cathode 103 side.

[0022] Further, the first light-emitting layer 115a may be configured to include a first phosphorescent material 121a, a first electron transporting material 122a, and further a first hole transporting material 123a. Also, the second light-emitting layer 115b may be configured to include a second phosphorescent material 131a, a second electron transporting material 132a, and further a second hole transporting material 133a.

[0023] In the first light-emitting layer 115a, the first electron transporting material 122a functions as a host material and the first phosphorescent material 121a functions as a guest material (also referred to as a dopant). Also, the first hole transporting material 123a functions as an assist material. That is, it is a configuration in which the first phosphorescent material 121a and the first hole transporting material 123a are dispersed in the first electron transporting material 122a that functions as a host material. Also, in the second light-emitting layer 115b the second electron transporting material 132a functions as a host material, the second phosphorescent material 131a functions as a guest material. Also, the second hole transporting material 133a functions as an assist material. That is, it is a configuration in which the second phosphorescent material 131a and the second hole transporting material 133a are dispersed in the second electron transporting material 132a that functions as a host material. Also, in the third light-emitting layer 115c, the third electron transporting material 142a functions as a ho st material, and the fluorescent material 141a functions as a guest material. That is, it is a configuration in which the fluorescent material 141a is dispersed in the third electron transporting material 142a that functions as a host material. Also, in the third light-emitting layer 115c, the third electron transporting material 142a functions as a host material, and the fluorescent material 141a functions as a guest material. That is, it is a configuration in which the fluorescent material 141a is dispersed in the third electron transporting material 142a that functions as a host material. For example, as the first phosphorescent material 121a, a phosphorescent material that exhibits red light emission can be used as a luminescent substance and as the second phosphorescent material 131a, a material that exhibits green light emission can be used. It is a configuration in which the fluorescent material 141a is dispersed in the third electron transporting material 142a that functions as a host material.

[0024] For example, as the first phosphorescent material 121a, a phosphorescent material that exhibits red light emission can be used as a luminescent substance and as the second phosphorescent material 131a, a material that exhibits green light emission can be used. A phosphorescent material can be used as a luminescent substance. Further, as the fluorescent material 141a, a fluorescent material that exhibits blue emission can be used as a luminescent substance. In this specification, the maximum emission wavelength of the phosphorescent material that exhibits red emission is greater than 570 nm and equal to or less than 740 nm, the maximum emission wavelength of the phosphorescent material that exhibits green emission is greater than 500 nm and equal to or less than 570 nm, and the maximum emission wavelength of the fluorescent material that exhibits blue emission is 400 nm or more and equal to or less than 500 nm.

[0025] Also, in FIG. 1(A), between a pair of electrodes, in addition to the light-emitting layer 115 and the electron transport layer 117, a hole injection layer 111, a first hole transport layer 113a, a second hole transport layer 113b, a third hole transport layer 113c, and an electron injection layer 119 are formed.

[0026] More specifically, the light-emitting element shown in FIG. 1(A) includes an anode 101 on a substrate 100, a hole injection layer 111 on the anode 101, a first hole transport layer 113a on the hole injection layer 111, a second hole transport layer 113b on the hole injection layer 111, a third hole transport layer 113c on the hole injection layer 111, a first light-emitting layer 115a on the first hole transport layer 113a, a second light-emitting layer 115b on the second hole transport layer 113b, a third light-emitting layer 11 5c on the third hole transport layer 113c, an electron transport layer 117 on the first light-emitting layer 115a, the second light-emitting layer 115b, and the third light-emitting layer 115c, an electron injection layer 119 on the electron transport layer 117, and a cathode 103 on the electron injection layer 119.

[0027] Thus, as necessary, layers other than the light-emitting layer 115 and the electron transport layer 117 are provided between a pair of electrodes. , for example, a hole-injecting or electron-injecting substance, a hole-transporting or electron-transporting substance , or a layer containing a bipolar substance (a substance with high electron-transporting and hole-transporting properties), etc. may be formed . However, these are not necessarily required.

[0028] Further, in the light-emitting element shown in Fig. 1(A), the first hole-transporting layer 113a, the second hole-transporting layer 113b, and the third hole-transporting layer 113c are respectively disposed with respect to each light-emitting layer (the first light-emitting layer 115a , the second light-emitting layer 115b, and the third light-emitting layer 115c). However, the present invention is not limited to this configuration, and the hole-transporting layer may be commonly formed for each light-emitting layer . Further, in the light-emitting element shown in Fig. 1(A), by adjusting the film thicknesses of the first hole-transporting layer 113a, the second hole-transporting layer 113b, and the third hole-transporting layer 113c, the optical distance of the light emitted from each light-emitting layer can be adjusted.

[0029] Further, in the light-emitting element shown in Fig. 1(A), the light-emitting layer 115 (the first light-emitting layer 115a, the second light-emitting layer 115b, and the third light-emitting layer 115c) shares the electron-transporting layer 117, the electron-injecting layer 119, and the cathode 103. Thus, by commonly using the electron-transporting layer 117, the electron-injecting layer 11 9, and the cathode 103 for the light-emitting layer 115, the productivity during the formation of the light-emitting element can be improved. Note that the coating process during the formation of the light-emitting element shown in Fig. 1(A) is to form the first hole-transporting layer 113a, the second hole-transporting layer 113b, and the third hole-transporting layer 113c on the hole-injecting layer 111, and to form the first light-emitting layer 115a, the second light-emitting layer 115b, and the third light-emitting layer 115c on the first hole-transporting layer 113a, the second hole-transporting layer 113b, and the third hole-transporting layer 113c, respectively. It is formed on the hole transport layer 113c of 3. Also, each hole transport layer and each light-emitting layer are formed continuously. By doing so, it is possible to reduce the number of coating times. For example, the first hole transport layer 11 3a and the first light-emitting layer 115a are formed continuously, and the second hole transport layer 113b and the second light-emitting layer 115b are formed continuously, and the third hole transport layer 113c and the third light-emitting layer 115c are continuous formed. Therefore, the light-emitting element shown in Fig. 1(A) can be formed with a total of 3 coatings. can be formed.

[0030] Also, in the light-emitting element shown in Fig. 1(A), the electron transport properties of the first electron transport material 122a and the second electron transport material 132a are very high. Therefore, the light-emitting regions of the first light-emitting layer 115a and the second light-emitting layer 115b are formed in the regions near the first hole transport layer 113a and the second hole transport layer 11 3b. Therefore, the light emission from the first light-emitting layer 115a and the second light-emitting layer 115 b is not affected by the triplet excitation energy level of the electron transport layer 117, or is extremely little affected, even though the triplet excitation energy level of the electron transport layer 117 is lower than the triplet excitation energies of the first electron transport material 122a and the second electron transport material 132a. That is, in the light-emitting element of one aspect of the present invention, in the first light-emitting layer 115a, the second light-emitting layer 11

[0031] 5b, and the third light-emitting layer 115c, even when a common electron transport layer 117 is used, in each light-emitting layer, an optimized element configuration can be achieved, with high productivity and a light-emitting element with high luminous efficiency can be realized. That is, in the light-emitting element of one aspect of the present invention, in the first light-emitting layer 115a, the second light-emitting layer 11 5b, and the third light-emitting layer 115c, even when a common electron transport layer 117 is used, in each light-emitting layer, an optimized element configuration can be achieved, with high productivity and

[0032] Next, the light-emitting element shown in Fig. 1(B) will be described below.

[0033] The light-emitting element shown in Fig. 1(B) has a light-emitting layer 1 15 between a pair of electrodes (anode 101 and cathode 103), and the light-emitting layer 115 includes a first phosphorescent material 121a and a first electron transport material 122 a to form a first light-emitting layer 115a, a second phosphorescent material 131a and a second electron transport material 1 32a to form a second light-emitting layer 115b, and a third light-emitting layer 1 15c that covers the first light-emitting layer 115a and the second light-emitting layer 115b and includes a fluorescent material 141a and a third electron transport material 142a.

[0034] Also, the third light-emitting layer 115c is provided in contact with the cathode 103 side of the first light-emitting layer 115a and the second light-emitting layer 115b.

[0035] The first light-emitting layer 115a may also be configured to include a first phosphorescent material 121a, a first electron transport material 122a, and further a first hole transport material 123a. Also, the second light-emitting layer 115b may be configured to include a second phosphorescent material 131a, a second electron transport material 132a, and further a second hole transport material 133a.

[0036] Also, in Fig. 1(B), between the pair of electrodes, in addition to the light-emitting layer 115, a hole injection layer 1 11, a first hole transport layer 113a, a second hole transport layer 113b, a third hole transport layer 113 c, and an electron injection layer 119 are formed. However, these may be provided as necessary.

[0037] More specifically, the light-emitting element shown in Fig. 1(B) includes an anode 101 on a substrate 100, a hole injection layer 111 on the anode 1 01, a first hole transport layer 113a on the hole injection layer 111, and a hole ​​The second hole transport layer 113b on the injection layer 111 and the third hole transport layer 113c on the hole injection layer 111, the first light-emitting layer 115a on the first hole transport layer 113a, and the second hole transport layer 113b on the second light-emitting layer 115b, the first light-emitting layer 115a, the second light-emitting layer 115b, and the third light-emitting layer 115c on the third hole transport layer 113c, and the electron injection layer 119 on the third light-emitting layer 115c and the cathode 103 on the electron injection layer 119.

[0038] In the light-emitting element shown in FIG. 1(B), the third light-emitting layer 115c functions as an electron transport layer for the light-emitting layer and the first light-emitting layer 115a and the second light-emitting layer 115b.

[0039] Since the electron transport properties of the first electron transport material 122a and the second electron transport material 132a are high, the fluorescent material 141a contained in the third light-emitting layer 115c does not contribute to light emission in the first light-emitting layer 1 115a and the second light-emitting layer 115b. On the other hand, in the third light-emitting layer 115 c, light emission from the fluorescent material 141a contained in the third light-emitting layer 115c can be obtained .

[0040] That is, in the light-emitting element according to one aspect of the present invention, since the third light-emitting layer 115c simultaneously has the functions of an electron transport layer and a light-emitting layer, it is possible to commonly use the third light-emitting layer 115c as an electron transport layer above the first light-emitting layer 115a and above the second light-emitting layer 115b, and the third It is possible to use the third light-emitting layer 115c as a light-emitting layer above the hole transport layer 113c. Therefore, a light-emitting element with high productivity and high luminous efficiency can be realized . Note that the coating process during the formation of the light-emitting element shown in FIG. 1(B) is the first hole transport layer 1 41 ​13a, the second hole transport layer 113b, and the third hole transport layer 113c are formed on the hole injection layer 111 above, the first light-emitting layer 115a and the second light-emitting layer 115b are respectively formed on the first hole transport layer 113a and the second hole transport layer 113b, and the third light-emitting layer 115c is formed on the first light emitting layer 115a, the second light-emitting layer 115b, and the third hole transport layer 113c. Also by continuously forming each hole transport layer and each light-emitting layer, the number of coating times can be reduced is possible. For example, the first hole transport layer 113a and the first light-emitting layer 115a are continuously formed and the second hole transport layer 113b and the second light-emitting layer 115b are continuously formed, and the third hole transport layer 113c is formed. Then, the third light-emitting layer 115c is formed on the first light-emitting layer 115a, the second light-emitting layer 115b, and the third hole transport layer 113c. Therefore, the light-emitting element shown in FIG. 1(B) can be formed by a total of three coatings. Also, the light-emitting element shown in FIG. 1(B) can omit the step of forming the electron transport layer 117 compared to the light-emitting element shown in FIG. 1(A). Here, other components of the light-emitting elements shown in FIGS. 1(A) and 1(B) will be described in detail below.

[0041] Here, other components of the light-emitting elements shown in FIGS. 1(A) and 1(B) will be described in detail below. explain.

[0042] <Substrate> The substrate 100 is used as a support for the light-emitting element. As the substrate 100, for example, glass , quartz, or plastic can be used. Also, a flexible substrate may be used . A flexible substrate is a substrate that can be bent (flexible), and for example, a plastic substrate made of polycarbonate, polyarylate, or polyethersulfone etc. can be mentioned. Also, films (polypropylene, polyester, polyvinyl fluoride, poly etc.)​ (made of vinyl chloride, etc.), an inorganic vapor deposition film, etc. can also be used. In addition, as long as it functions as a support in the manufacturing process of the light-emitting element, other materials may be used. (as long as it functions as a support in the manufacturing process of the light-emitting element, other materials may be used.)

[0043] <Anode> Anode 101 can be formed by using one or more kinds of conductive metals, alloys, conductive compounds, etc. In particular, it is preferable to use a material with a large work function (4.0 eV or more). For example, indium tin oxide (ITO: Indium Tin Oxide) (as long as it functions as a support in the manufacturing process of the light-emitting element, other materials may be used.), indium tin oxide containing silicon or silicon oxide, indium zinc oxide, indium oxide containing tungsten oxide and zinc oxide, graphene, gold, platinum, nickel (as long as it functions as a support in the manufacturing process of the light-emitting element, other materials may be used.), tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, or nitrides of metal materials (for example, titanium nitride), etc. can be mentioned. Or, silver, copper, aluminum, titanium (as long as it functions as a support in the manufacturing process of the light-emitting element, other materials may be used.) etc. are formed in the shape of nanowires (or fine wires), and a conductive substance (such as a conductive organic material or graphene) is formed thereon by a coating method, a printing method, etc. to form the anode 101. (as long as it functions as a support in the manufacturing process of the light-emitting element, other materials may be used.) (as long as it functions as a support in the manufacturing process of the light-emitting element, other materials may be used.) It is also possible. (as long as it functions as a support in the manufacturing process of the light-emitting element, other materials may be used.) (as long as it functions as a support in the manufacturing process of the light-emitting element, other materials may be used.) etc. are formed in the shape of nanowires (or fine wires), and a conductive substance (such as a conductive organic material or graphene) is formed thereon by a coating method, a printing method, etc. to form the anode 101. (as long as it functions as a support in the manufacturing process of the light-emitting element, other materials may be used.) (as long as it functions as a support in the manufacturing process of the light-emitting element, other materials may be used.)

[0044] <Cathode> Cathode 103 can be formed by using one or more kinds of conductive metals, alloys, conductive compounds, etc. In particular, it is preferable to use a material with a small work function (3.8 eV or less). For example, elements belonging to Group 1 or Group 2 of the periodic table of elements (for example, alkali metals such as lithium and cesium, alkaline earth metals such as calcium and strontium, magnesium (as long as it functions as a support in the manufacturing process of the light-emitting element, other materials may be used.) etc.), alloys containing these elements (for example, Mg-Ag, Al-Li), europium, (as long as it functions as a support in the manufacturing process of the light-emitting element, other materials may be used.) etc., rare earth metals such as ytterbium, alloys containing these rare earth metals, aluminum, silver, etc. (as long as it functions as a support in the manufacturing process of the light-emitting element, other materials may be used.) (as long as it functions as a support in the manufacturing process of the light-emitting element, other materials may be used.) etc.), alloys containing these elements (for example, Mg-Ag, Al-Li), europium, (as long as it functions as a support in the manufacturing process of the light-emitting element, other materials may be used.) etc., rare earth metals such as ytterbium, alloys containing these rare earth metals, aluminum, silver, etc. can be used. can exist.

[0045] <Hole injection layer and hole transport layer> As the high hole-transporting material used for the hole injection layer 111, the first hole transport layer 113a, the second hole transport layer 113b, and the third hole transport layer 113c, for example, 4,4'-bis [N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB or α-N PD), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'- biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4',4''-tris(car bazoyl-9-yl)triphenylamine (abbreviation: TCTA), 4,4',4''-tri s(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4', 4''-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: MTDATA), 4,4'-bis[N-(spiro-9,9'-bifluorene- 2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB) and other aromatic amine compounds, 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9 -phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenyl carbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3 -yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1), etc. can be mentioned. In addition, 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 1,3,5 -tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB), 9-[4 -[10-Phenyl-9-anthracenyl]phenyl]-9H-carbazole (abbreviation: C arbazole derivatives such as zPA) can be used. The substances described here are mainly 10 -6 cm 2 substances having a hole mobility of / Vs or more. However, as long as the substance has a higher hole transport property than electrons, other substances may be used.

[0046] Furthermore, as the hole injection layer 111, the first hole transport layer 113a, the second hole transport layer 113b, and the third hole transport layer 113c, poly(N-vinylcarbazole) (abbreviation: PVK ), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{ N’-[4-(4-diphenylamino)phenyl]phenyl-N’-phenylamino}phenyl )methacrylamide] (abbreviation: PTPDMA), poly[N,N’-bis(4-butyl phenyl)-N,N’-bis(phenyl)benzidine] (abbreviation: Poly-TPD), etc. of polymer compounds can also be used.

[0047] In addition, as acceptor substances that can be used for the hole injection layer 111, the first hole transport layer 113a, the second hole transport layer 113b, and the third hole transport layer 113c, transition metal oxides can be mentioned. As the transition metal oxides, oxides of metals belonging to Groups 4 to 8 in the periodic table are preferable. Specifically, molybdenum oxide is particularly preferable.

[0048] <First Light Emitting Layer> The first light emitting layer 115a includes a first phosphorescent material 121a (guest material), a first electron transport material 122a (host material), and a first hole transport material 123a (assist material). It has. Further, the first light-emitting layer 115a preferably exhibits red light emission.

[0049] Incidentally, the T1 level of the host material (or the assist material) is preferably higher than the T1 level of the guest material. If the T1 level of the host material is lower than the T1 level of the guest material, the host material quenches the triplet excitation energy of the guest material contributing to light emission, resulting in a decrease in light emission efficiency.

[0050] Also, the first phosphorescent material 121a (guest material), the first electron transporting material 122a (host material), and the first hole transporting material 123a (assist material) are a combination capable of forming an exciplex, and the emission spectrum of the exciplex overlaps with the absorption spectrum of the first phosphorescent material 121a (guest material), and it is preferable that the peak of the emission spectrum of the exciplex is at a longer wavelength than the peak of the absorption spectrum of the first phosphorescent material 121a (guest material).

[0051] Here, in order to increase the energy transfer efficiency from the host material to the guest material, considering the Förster mechanism (dipole-dipole interaction) and the Dexter mechanism (electron exchange interaction) known as intermolecular transfer mechanisms, the emission spectrum of the host material (fluorescence spectrum when discussing energy transfer from the singlet excited state, phosphorescence spectrum when discussing energy transfer from the triplet excited state) and the absorption spectrum of the guest material (more specifically, the spectrum in the absorption band on the longest wavelength (lowest energy) side) preferably have a larger overlap.

[0052] However, usually, the fluorescence spectrum of the host material is such that ​​​​​​​​​​​​It is difficult to overlap with the absorption spectrum in the absorption band on the (long wavelength) side. This is because, if done in such a way, since the phosphorescence spectrum of the host material is located on the longer wavelength (lower energy) side than the fluorescence spectrum, the T1 level of the host material will fall below the T1 level of the phosphorescent compound, causing the quenching problem described above. On the other hand, in order to avoid the quenching problem, if the T1 level of the host material is designed to be higher than the T1 level of the phosphorescent compound, then this time the fluorescence spectrum of the host material will shift to the shorter wavelength (higher energy) side. Therefore, its fluorescence spectrum will not overlap with the absorption spectrum in the absorption band on the longest wavelength (lowest energy) side of the guest material. Thus, it is usually difficult to overlap the fluorescence spectrum of the host material with the absorption spectrum in the absorption band on the longest wavelength (lowest energy) side of the guest material and maximize the energy transfer from the singlet excited state of the host material. If this is the case, since the phosphorescence spectrum of the host material is located on the longer wavelength (lower energy) side than the fluorescence spectrum, the T1 level of the host material will fall below the T1 level of the phosphorescent compound, resulting in the quenching problem described above. On the other hand, to avoid the quenching problem, if the T1 level of the host material is designed to be higher than the T1 level of the phosphorescent compound, then this time the fluorescence spectrum of the host material will shift to the shorter wavelength (higher energy) side. Therefore, its fluorescence spectrum will not overlap with the absorption spectrum in the absorption band on the longest wavelength (lowest energy) side of the guest material. Thus, it is usually difficult to overlap the fluorescence spectrum of the host material with the absorption spectrum in the absorption band on the longest wavelength (lowest energy) side of the guest material and maximize the energy transfer from the singlet excited state of the host material. Therefore, it is usually difficult to overlap the fluorescence spectrum of the host material with the absorption spectrum in the absorption band on the longest wavelength (lowest energy) side of the guest material and maximize the energy transfer from the singlet excited state of the host material.

[0053] Therefore, the first light-emitting layer 115a included in the light-emitting device according to one aspect of the present invention contains, in addition to the first phosphorescent material 121a (referred to as the first substance) which is a guest material and the first electron-transporting material 122a (referred to as the second substance) which is a host material, a first hole-transporting material 123a (referred to as the third substance). It is preferable that the host material and the third substance are a combination that forms an exciplex (also referred to as an exciplex). In this case, when carriers (electrons and holes) recombine in the light-emitting layer, the host material and the third substance form an exciplex. In this case, when carriers (electrons and holes) recombine in the light-emitting layer, the host material and the third substance form an exciplex. In addition to the first phosphorescent material 121a (which is the first substance) that is the guest material and the first electron-transporting material 122a (which is the second substance) that is the host material, it contains a first hole-transporting material 123a (which is the third substance). It is preferable that the host material and the third substance are a combination that forms an exciplex (also referred to as an exciplex). In this case, when carriers (electrons and holes) recombine in the light-emitting layer, the host material and the third substance form an exciplex.

[0054] As a result, in the light-emitting layer, the fluorescence spectrum of the host material and the fluorescence spectrum of the third substance are converted into the emission spectrum of the exciplex located on the longer wavelength side. And, when carriers (electrons and holes) recombine in the light-emitting layer, the host material and the third substance form an exciplex. So that the overlap between the emission spectrum of the exciplex and the absorption spectrum of the guest material becomes large, by selecting a host material and a third substance, energy transfer from the singlet excited state can be maximized In one aspect of the present invention to which such a configuration is applied, the energy transfer efficiency can be increased by energy transfer using the overlap between the emission spectrum of the exciplex and the absorption spectrum of the phosphorescent compound, so that a light-emitting device with high external quantum efficiency

[0055]

[0056]

[0057] Tanatoiridium(III) (abbreviation: [Ir(5mdppm)2(dpm)]), bis [4,6 - Di(naphthalen - 1 - yl)pyrimidinato](dipivaloylmethanato)iridium (III) (abbreviation: [Ir(d1npm)2(dpm)]) and other organometallic iridium complexes having a pyrimidine skeleton or (acetylacetonato)bis(2,3,5 - triphenylpyrazinato)iridium(III) (abbreviation: [Ir(tppr)2(acac)]) ([Ir(tppr)2(acac)]), bis(2,3,5 - triphenylpyrazinato)(dipivaloylmethanato)iridium (III) (abbreviation: [Ir(tppr)2(dpm)]), (acetylacetonato)bis [2,3 - Bis(4 - fluorophenyl)quinoxalinato]iridium(III) (abbreviation :[Ir(Fdpq)2(acac)]) and other organometallic iridium complexes having a pyrazine skeleton or tris(1 - phenylisoquinolinato - N,C )iridium(III) 2’ (abbreviation: [Ir(piq)3]), bis(1 - phenylisoquinolinato - N,C )iridium 2’ (III) acetylacetonate (abbreviation: [Ir(piq)2(acac)]) and other organometallic iridium complexes having a pyridine skeleton can be mentioned. Among the above, organometallic iridium complexes having a pyrimidine skeleton are particularly preferable because they are remarkably excellent in reliability and luminescence efficiency. Also, organometallic iridium complexes having a pyrazine skeleton can obtain good red luminescence with good chromaticity. As the first electron - transporting material 122a that can be used for the first light - emitting layer 115a, π - electron - deficient heteroaromatic compounds such as nitrogen - containing heteroaromatic compounds are preferable. For example, 2

[0058] ​​​-(4-Biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxa diazole (abbreviation: PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-t ert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 1,3-bis [5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl] benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiaz ol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 2,2’,2’ ’-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazo le)(abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1 -phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), etc., heterocyclic compounds having a polyazole skeleton (oxadiazole derivatives, imidazole derivatives, tria zole derivatives, etc.), and 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo [f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3’-(dibenz othiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation : 2mDBTBPDBq-II), 2-[3’-(9H-carbazol-9-yl)bip enyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 4 ,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6m PnP2Pm), 4,6-bis〔3-(4-dibenzothienyl)phenyl〕pyrimidine( abbreviation: 4,6mDBTP2Pm-II), etc., heterocyclic compounds having a diazine skeleton (pyra dine derivatives, pyrimidine derivatives, pyridazine derivatives, quinoxaline derivatives, dibenzoquinone xanthine derivatives, etc., and 3,5-bis(9H-carbazol-9-yl)phenyl)pyr dine (abbreviation: 3,5DCzPPy), 1,3,5-tri[(3-pyridyl)-phen-3 -yl]benzene (abbreviation: TmPyPB), and other heterocyclic compounds having a pyridine skeleton (pyr idine derivatives, quinoline derivatives, dibenzoquinoline derivatives, etc.). Among the above-mentioned However, heterocyclic compounds having a diazine skeleton and heterocyclic compounds having a pyridine skeleton are preferred because of their good reliability. In particular, heterocyclic compounds having a diazine (pyrimidine or pyrazine) skeleton have high electron transport properties and contribute to reducing the driving voltage.

[0059] In addition, as the first hole transporting material 123a that can be used in the first light emitting layer 115a, π-electron excess type heteroaromatic compounds (for example, carbazole derivatives and indole derivatives) and aromatic amine compounds are preferred. For example, 4,4'-bis[N-(1-naphthyl)-N -phenylamino]biphenyl (abbreviation: NPB), N,N'-bis(3-methylphenyl )-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: T PD), 4,4'-bis[N-(spiro-9,9'-bifluorene-2-yl)-N―f enylamino]biphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylf luoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3' -(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP) 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenyl amine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9 (H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-( 1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenyl amine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phen yl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), 9, 9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl yl)phenyl]-fluorene-2-amine (abbreviation: PCBAF), N-phenyl-N- [4-(9-phenyl-9H-carbazol-3-yl)phenyl]-spiro-9,9'- bifluorene-2-amine (abbreviation: PCBASF), etc., compounds having an aromatic amine skeleton, 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N -carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphen yl)-9-phenyl-carbazole (abbreviation: CzTP), 3,3'-bis(9-phen yl-9H-carbazole) (abbreviation: PCCP), etc., compounds having a carbazole skeleton, and, 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H- fluorene-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III) , 4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]-6-phenyl dibenzothiophene (abbreviation: DBTFLP-IV), etc., compounds having a thiophene skeleton and, 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran)( (abbreviation: DBF3P-II), 4-{3-[3-(9-phenyl-9H-fluorene-9- Compounds such as {[1,1'-biphenyl]-3-yl}phenyl dibenzofuran (abbreviation: mmDBFFLBi-II) having a furan skeleton are exemplified. Among those described above, compounds having an aromatic amine skeleton or a carbazole skeleton are preferable because they have good reliability, high hole transportability, and contribute to reducing the driving voltage.

[0060] <Second light-emitting layer> The second light-emitting layer 115b includes a second phosphorescent material 131a (guest material), a second electron transporting material 132a (host material), and a second hole transporting material 133a (assist material). Also, the second light-emitting layer 115b preferably exhibits green light emission.

[0061] Also, the second phosphorescent material 131a (guest material), the second electron transporting material 132a (host material), and the second hole transporting material 133a (assist material) are a combination capable of forming an exciplex, and the emission spectrum of the exciplex overlaps with the absorption spectrum of the second phosphorescent material 131a (guest material), and it is preferable that the peak of the emission spectrum of the exciplex is at a longer wavelength than the peak of the absorption spectrum of the second phosphorescent material 131a (guest material). Regarding the configuration of the exciplex, the same configuration as that of the first light-emitting layer 115a can also be applied to the second light-emitting layer 115b.

[0062] Also, when using the second electron transporting material 132a (host material) and the second hole transporting material 133a (assist material), the carrier balance can be controlled by their mixing ratio. Specifically, it is preferable that the ratio of the second electron transporting material 132a: the second hole transporting material 133a = 1:9 to 9:1 (weight ratio). ​​​​​​​​​​​​

[0063] In addition, since energy transfer (exciton diffusion) between exciplexes is unlikely to occur, exciton diffusion to the electron transport layer 117 can be prevented by using the exciplex as described above.

[0064] Examples of the second phosphorescent material 131a that can be used for the second light-emitting layer 115b include phosphorescent materials having a peak emission at 520 nm to 600 nm. Examples of the phosphorescent material include tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)3]), tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)3]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)2(acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]), (acetylacetonato)bis[4-(2-norbornyl)-6-phenylpyrimidinato]iridium(III) (endo-, exo-mixture) (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-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm)2(acac)]) and other organometallic iridium complexes having a pyrimidine skeleton, and (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III) (abbreviation: :[Ir(mppr-Me)2(acac)]), bis(acetylacetonato)(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium(III) (abbreviation: [I r(mppr-iPr)2(acac)]), and organometallic iridium complexes having a pyrazine skeleton such as tris(2-phenylpyridinato-N,C )iridium(III)( 2’ ) (abbreviation: [Ir(ppy)3]), bis(2-phenylpyridinato-N,C )iridium 2’ (III) acetylacetonate (abbreviation: [Ir(ppy)2(acac)]), bis (benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: [Ir (bzq)2(acac)]), tris(benzo[h]quinolinato)iridium(III )(abbreviation: [Ir(bzq)3]), tris(2-phenylquinolinato-N,C )iridium 2’ (III)(abbreviation: [Ir(pq)3]), bis(2-phenylquinolinato-N ,C )iridium(III) acetylacetonate (abbreviation: [Ir(pq)2(ac 2’ ac)]), and organometallic iridium complexes having a pyridine skeleton such as these can be mentioned. Among those described above, organometallic iridium complexes having a pyrimidine skeleton are particularly preferable because they are also excellent in reliability and luminous efficiency. As the second electron transporting material 132a that can be used for the second light emitting layer 115b, the same materials as those shown for the first electron transporting material 122a can be used. Also, as the second hole transporting material 133a that can be used for the second light emitting layer 115b, the same materials as those shown for the first hole transporting material 123a can be used. Among those described above, organometallic iridium complexes having a pyrimidine skeleton are particularly preferable because they are also excellent in reliability and luminous efficiency.

[0065] As the second electron transporting material 132a that can be used for the second light emitting layer 115b, the same materials as those shown for the first electron transporting material 122a can be used. Also, as the second hole transporting material 133a that can be used for the second light emitting layer 115b, the same materials as those shown for the first hole transporting material 123a can be used.

[0066] <Third light-emitting layer> The third light-emitting layer 115c includes a fluorescent material 141a (guest material) and a third electron-transporting material 142a (host material). Further, the third light-emitting layer 115c preferably exhibits blue light emission.

[0067] Examples of the fluorescent material 141a that can be used in the third light-emitting layer 115c include N,N’- bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-N,N’-diphenyl-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: 1,6mMemFLPAPrn) , N,N’-bis[4-(9H-carbazol-9-yl)phenyl]-N,N’-diphenylstilbene-4,4’-diamine (abbreviation: YGA2S), 4-(9H-carbazol- 9-yl)-4’-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazol-9-yl)-4’-(9,10-diphenyl- 2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole- 3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra-tert-butylperylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4’-(9- phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA ), etc. In particular, fluorescent compounds having a pyrene skeleton have high hole-trapping properties, ) and the like. ​​​​​​It is preferable because it has excellent luminous efficiency and reliability. Also, 1,6FLPAPrn and 1,6 mM Condensed aromatic diamine compounds typified by pyrene diamine compounds such as emFLPAPrn have high hole trapping properties and are preferable because they have excellent luminous efficiency and reliability.

[0068] As the third electron transporting material 142a that can be used for the third light emitting layer 115c, for example, an organic compound containing an anthracene skeleton is preferable. As the organic compound containing the anthracene skeleton, for example, 9-[4-(10-phenyl-9-anthracenyl)phenyl -9H-carbazole (abbreviation: CzPA), 9-phenyl-3-[4-(10-phenyl -9-anthryl)phenyl]-9H-carbazole (abbreviation: PCzPA), 3,6- diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carb azole (abbreviation: DPCzPA), 9,10-bis(3,5-diphenylphenyl)anth racene (abbreviation: DPPA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA ), 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-B uDNA), etc., which are electron transporting and easily receive holes, can be preferably used. In the light emitting device of one aspect of the present invention, the third electron transporting material 142a preferably has an anth racene skeleton because it not only has electron transporting properties but also easily receives holes.

[0069] <Electron Transport Layer> The electron transport layer 117 is a layer containing a material with high electron transporting properties. Also, the triplet excitation energy level of the material forming the electron transport layer 117 is higher than that of the first light emitting layer 115a and the second light emitting layer The triplet of the first electron transporting material 122a and the second electron transporting material 132a used for 115b is a material lower than the singlet excitation energy level. As such a material, the same material as the third electron transporting material 142a that can be used for the third light emitting layer 115c can be used.

[0070] <Electron injection layer> The electron injection layer 119 is a layer containing a substance with high electron injection property. In the electron injection layer 119, compounds of alkali metals or alkaline earth metals such as lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2) , lithium oxide (LiOx), etc. can be used. Also, rare earth metal compounds such as erbium fluoride (ErF3) can be used.

[0071] Alternatively, a composite material formed by mixing an organic compound and an electron donor can be used for the electron injection layer 119. Since such a composite material generates electrons in the organic compound by the electron donor, it is excellent in electron injection property and electron transport property. In this case, as the organic compound it is preferably a material excellent in transporting the generated electrons, and as the electron donor, any substance that shows electron donating property to the organic compound may be used. Specifically, alkali metals, alkaline earth metals, and rare earth metals are preferable, and examples include lithium, cesium, magnesium, calcium, erbium, ytterbium, etc. Also, alkali metal oxides and alkaline earth metal oxides are preferable, and examples include lithium oxide, calcium oxide, barium oxide, etc. Also, a Lewis base such as magnesium oxide can be used. Also, organic compounds such as tetrathiafulvalene (abbreviation: TTF) can be used. ​​​​​​​

[0072] Note that the above-described hole injection layer 111, first hole transport layer 113a, second hole transport layer 11 3b, third hole transport layer 113c, first light-emitting layer 115a, second light-emitting layer 115b, third light-emitting layer 115c, electron transport layer 117, and electron injection layer 119 can each be formed by a method such as vapor deposition (including vacuum vapor deposition), inkjet printing, coating, etc. Also, the light emission obtained from the first light-emitting layer 115a, second light-emitting layer 115b, and third light-emitting layer 115c of the light-emitting device described above is taken out to the outside through either one or both of the anode 101 and the cathode 103. Therefore, either one or both of the anode 101 and the cathode 103 in the present embodiment are electrodes having translucency.

[0073] Note that the configuration shown in the present embodiment can be appropriately combined with the configuration shown in other embodiments or examples.

[0074]

[0075]

[0076] (Embodiment 2) In the present embodiment, a modified example of the light-emitting device according to one aspect of the present invention shown in FIG. 1 will be described with reference to FIGS. 2 and 3. Note that the same parts or parts having the same functions as those shown in the previous embodiment are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0076] The light-emitting device shown in FIG. 2(A) has a light-emitting layer 1 15 between a pair of electrodes (anode 101 and cathode 103), and the light-emitting layer 115 includes a first light-emitting layer 115a containing a first phosphorescent material 121a and a first electron-transporting material 122 a, a second light-emitting layer 115b containing a second phosphorescent material 131a and a second electron-transporting material 1 32a, and a fluorescent material 141a and a third electron-transporting material 14 It has a third light-emitting layer 115c containing 2a.

[0077] In addition, each of the first light-emitting layer 115a, the second light-emitting layer 115b, and the third light-emitting layer 115c is provided in contact with an electron transport layer 117 disposed on the cathode 103 side.

[0078] In addition, the first light-emitting layer 115a may be configured to include a first phosphorescent material 121a, a first electron-transporting material 122a, and further a first hole-transporting material 123a. Also, the second light-emitting layer 115b may be configured to include a second phosphorescent material 131a, a second electron-transporting material 132a, and further a second hole-transporting material 133a.

[0079] Also, in FIG. 2(A), between the pair of electrodes, in addition to the light-emitting layer 115 and the electron transport layer 117, a hole injection layer 111, a first hole transport layer 113a, a second hole transport layer 113b, a fourth hole transport layer 113d, and an electron injection layer 119 are formed.

[0080] More specifically, the light-emitting element shown in FIG. 2(A) includes an anode 101 on a substrate 100, a hole injection layer 111 on the anode 1 01, a fourth hole transport layer 113d on the hole injection layer 111, a first hole transport layer 113a on the fourth hole transport layer 113d, a second hole transport layer 113b on the fourth hole transport layer 113d, a first light-emitting layer 115a on the first hole transport layer 113a, a second light-emitting layer 115b on the second hole transport layer 113b, a third light-emitting layer 115c on the fourth hole transport layer 113d, an electron transport layer 117 on the first light-emitting layer 115a, the second light-emitting layer 115b, and the third light-emitting layer 115c, an electron injection layer 119 on the electron transport layer 117, and a cathode 103 on the electron injection layer 119. injection layer 119. It has a cathode 103 on the injection layer 119.

[0081] Next, the light-emitting element shown in FIG. 2(B) will be described below.

[0082] The light-emitting element shown in FIG. 2(B) has a light-emitting layer 115 between a pair of electrodes (anode 101 and cathode 103). The light-emitting layer 115 includes a first phosphorescent material 121a and a first electron-transporting material 122a to form a first light-emitting layer 115a, a second phosphorescent material 131a and a second electron-transporting material 132a to form a second light-emitting layer 115b, and a third light-emitting layer 115c that covers the first light-emitting layer 115a and the second light-emitting layer 115b and includes a fluorescent material 141a and a third electron-transporting material 142a. a, and a second light-emitting layer 115b including a second phosphorescent material 131a and a second electron-transporting material 132a, and a third light-emitting layer 115c that covers the first light-emitting layer 115a and the second light-emitting layer 115b and includes a fluorescent material 141a and a third electron-transporting material 142a. 32a, and a third light-emitting layer 115c that covers the first light-emitting layer 115a and the second light-emitting layer 115b and includes a fluorescent material 141a and a third electron-transporting material 142a. The third light-emitting layer 115c is provided in contact with the cathode 103 side of the first light-emitting layer 115a and the second light-emitting layer 115b. has.

[0083] Further, the third light-emitting layer 115c is provided in contact with the cathode 103 side of the first light-emitting layer 115a and the second light-emitting layer 115b. is provided.

[0084] The first light-emitting layer 115a may be configured to further include a first hole-transporting material 123a in addition to the first phosphorescent material 121a and the first electron-transporting material 122a. Further, the second light-emitting layer 115b may be configured to further include a second hole-transporting material 133a in addition to the second phosphorescent material 131a and the second electron-transporting material 132a. The second light-emitting layer 115b may be configured to further include a second hole-transporting material 133a in addition to the second phosphorescent material 131a and the second electron-transporting material 132a. Further, the second light-emitting layer 115b may be configured to further include a second hole-transporting material 133a in addition to the second phosphorescent material 131a and the second electron-transporting material 132a.

[0085] In FIG. 2(B), in addition to the light-emitting layer 115, a hole injection layer 111, a first hole-transporting layer 113a, a second hole-transporting layer 113b, a fourth hole-transporting layer 113 d, and an electron injection layer 119 are formed between the pair of electrodes. d, and an electron injection layer 119 are formed.

[0086] More specifically, the light-emitting element shown in FIG. 2(B) includes an anode 101 on a substrate 100, a hole injection layer 111 on the anode 101, a fourth hole-transporting layer 113d on the hole injection layer 111, and a fourth 01, a hole injection layer 111 on the anode 101, a fourth hole-transporting layer 113d on the hole injection layer 111, and a fourth The first hole transport layer 113a on the hole transport layer 113d of , and on the fourth hole transport layer 113d The second hole transport layer 113b, the first light-emitting layer 115a on the first hole transport layer 113a, The second light-emitting layer 115b on the second hole transport layer 113b, the first light-emitting layer 115a, the second The second light-emitting layer 115b, and the third light-emitting layer 115c on the fourth hole transport layer 113d, and the third light Emitting layer 115c has an electron injection layer 119 thereon, and a cathode 103 on the electron injection layer 119.

[0087] The light-emitting element shown in FIGS. 2(A) and (B) is different from the light-emitting element shown in FIGS. 1(A) and (B) In that a fourth hole transport layer 113d is provided on the hole injection layer 111. Further, the third The third light-emitting layer 115c is not provided with a third hole transport layer 113c. That is, the third The third light-emitting layer 115c is provided in contact with the fourth hole transport layer 113d. Also, the fourth The material that can be used for the fourth hole transport layer 113d can be the same material as the third hole transport layer 113c.

[0088] The fourth hole transport layer 113d can be commonly used for the first light-emitting layer 115a, the second light-emitting layer 115b, and the Third light-emitting layer 115c. Therefore, the light-emitting element shown in FIGS. 2(A) and (B) In addition to the excellent effects of the light-emitting element of one aspect of the present invention shown in FIGS. 1(A) and (B), The productivity during the formation of the light-emitting element can be further improved. Note that the painting process during the formation of the light-emitting element shown in FIG. 2(A) Is the first hole transport layer 113a, the second hole transport layer 113b , The first light-emitting layer 115a, the second light-emitting layer 115b, and the third light-emitting layer 115c. Also By continuously forming each hole transport layer and each light-emitting layer, the number of painting times can be reduced. It is possible. For example, the first hole transport layer 113a and the first light-emitting layer 115a are continuously formed and the second hole transport layer 113b and the second light-emitting layer 115b are continuous, and the third light-emitting layer 115c is formed. Therefore, the light-emitting element shown in Fig. 2(A) can be formed by a total of three coating operations This is possible. Also, in the coating process when forming the light-emitting element shown in Fig. 2(B), the first hole transport layer 113a, the second hole transport layer 113b, the first light-emitting layer 115a, and the second light-emitting layer 1 15b are obtained. Further, by continuously forming each hole transport layer and each light-emitting layer, the number of coating operations can be reduced. For example, the first hole transport layer 113a and the first light-emitting layer 115 a are continuously formed, and the second hole transport layer 113b and the second light-emitting layer 115b are continuously formed Therefore, the light-emitting element shown in Fig. 2(B) can be formed by a total of two coating operations This is possible.

[0089] Also, in the light-emitting elements shown in Figs. 2(A) and (B), the first light-emitting layer 115a and the second light-emitting layer 115b are each independently formed in contact with the first hole transport layer 113a and the second hole transport layer 113b. Therefore, an optimal element configuration can be achieved for each light-emitting layer, and a light-emitting element with high luminous efficiency can be realized for each of the light-emitting layers. This is possible.

[0090] Also, in the light-emitting elements shown in Figs. 2(A) and (B), by adjusting the film thicknesses of the first hole transport layer 113a, the second hole transport layer 113b, and the fourth hole transport layer 113d, the optical distance in each light-emitting layer can be adjusted.

[0091] Next, the light-emitting element shown in Fig. 3(A) will be described below.

[0092] The light-emitting element shown in FIG. 3A has a light-emitting layer 1 between a pair of electrodes (anode 101 and cathode 103). 15, and the light-emitting layer 115 includes a first phosphorescent material 121a and a first electron-transporting material 122. a first light-emitting layer 115a containing a second phosphorescent material 131a and a second electron-transporting material 132a. The second light-emitting layer 115b includes a fluorescent material 141a and a third electron-transporting material 14 and a third light-emitting layer 115c including 2a.

[0093] In addition, each of the first light-emitting layer 115a, the second light-emitting layer 115b, and the third light-emitting layer 115c This is provided in contact with the electron transport layer 117 arranged on the cathode 103 side.

[0094] The first light-emitting layer 115a is made of a first phosphorescent material 121a and a first electron transport material The second hole transport material 122a may further include a first hole transport material 123a. The light-emitting layer 115b includes a second phosphorescent material 131a, a second electron-transporting material 132a, and The second hole transporting material 133a may be further included.

[0095] In addition, in FIG. 3A, in addition to the light-emitting layer 115, a hole injection layer 1 11, a hole transport layer 113, and an electron injection layer 119 are formed.

[0096] More specifically, the light-emitting element shown in FIG. 3A includes an anode 101 on a substrate 100 and an anode 1 A hole injection layer 111 on the substrate 101, a hole transport layer 113 on the hole injection layer 111, and a hole transport layer 113 on the substrate 101. A first light-emitting layer 115a on the hole transport layer 113, a second light-emitting layer 115b on the hole transport layer 113, and a hole The third light-emitting layer 115c on the transport layer 113, the first light-emitting layer 115a, the second light-emitting layer 115 b, the electron injection layer 119 on the third light-emitting layer 115c, and the cathode 10 on the electron injection layer 119. It has 3 and

[0097] Next, the light-emitting element shown in FIG. 3(B) will be described below.

[0098] The light-emitting element shown in FIG. 3(B) has a light-emitting layer 1 15 between a pair of electrodes (anode 101 and cathode 103), and the light-emitting layer 115 includes a first phosphorescent material 121a and a first electron-transporting material 122 a, a first light-emitting layer 115a including a second phosphorescent material 131a and a second electron-transporting material 1 32a, a second light-emitting layer 115b, a first light-emitting layer 115a and a second light-emitting layer 115b covering them, and a third light-emitting layer 1 15c including a fluorescent material 141a and a third electron-transporting material 142a.

[0099] Also, the third light-emitting layer 115c is provided in contact with the cathode 103 side of the first light-emitting layer 115a and the second light-emitting layer 115b.

[0100] Also, the first light-emitting layer 115a may be configured to include a first phosphorescent material 121a, a first electron-transporting material 122a, and further a first hole-transporting material 123a. Also, the second light-emitting layer 115b may be configured to include a second phosphorescent material 131a, a second electron-transporting material 132a, and further a second hole-transporting material 133a.

[0101] Also, in FIG. 3(B), between the pair of electrodes, in addition to the light-emitting layer 115, a hole injection layer 1 11, a hole-transporting layer 113, and an electron injection layer 119 are formed.

[0102] More specifically, the light-emitting element shown in FIG. 3(B) includes an anode 101 on a substrate 100, a hole injection layer 1 01 on the anode 101, a hole-transporting layer 113 on the hole injection layer 111, and a hole-transporting layer 1 The first light-emitting layer 115a on 13, the second light-emitting layer 115b on the hole transport layer 113, and the first light-emitting layer 115a, the second light-emitting layer 115b, and the third light-emitting layer 11 5c on the hole transport layer 113, the electron injection layer 119 on the third light-emitting layer 115c, and the cathode 10 on the electron injection layer 119 3, and has.

[0103] The light-emitting element shown in FIGS. 3(A) and (B) is different from the light-emitting element shown in FIGS. 1(A) and (B) in that a hole transport layer 113 is provided on the hole injection layer 111. That is, the hole transport layer 113 can be used as a common hole transport layer for the first light-emitting layer 115a, the second light-emitting layer 115b, and the third light-emitting layer 115c . Also, as the material that can be used for the hole transport layer 113, the same material as the third hole transport layer 113c can be used. Therefore , the light-emitting element shown in FIGS. 3(A) and (B) can further improve the productivity during the formation of the light-emitting element in addition to the excellent effects of the light-emitting element of one aspect of the present invention shown in FIGS. 1(A) and (B). In addition , the painting process during the formation of the light-emitting element shown in FIG. 3(A) becomes the first light-emitting layer 115a, the second light-emitting layer 115b, and the third light-emitting layer 115c, for a total of 3 times. Also, the painting process during the formation of the light-emitting element shown in FIG. 3(B) becomes the first light-emitting layer 115a and the second light-emitting layer 11 5b, for a total of 2 times. However, in the element configuration shown in FIGS. 3(A) and (B), the first light-emitting layer 115a, the second light-emitting layer 115b, and the third light-emitting layer 115c commonly use the hole transport layer 113. Therefore

[0104] However, in the element configuration shown in FIGS. 3(A) and (B), in any one or two of the first light-emitting layer 115a, the second light-emitting layer 115b, and the third light-emitting layer 115c, the element characteristics may deteriorate. However, the element characteristics When prioritizing productivity, the configurations shown in FIGS. 3(A) and 3(B) may be applied. In the configurations shown in FIGS. 3(A) and 3(B), the electron transporting properties of the first electron transporting material 122a, the second electron transporting material 132a, and the third light emitting layer 115c are extremely high. Therefore, even when a common hole transporting layer is used for each light emitting layer, there is no or extremely little degradation in the device characteristics on the electron transporting layer side, so a light emitting device with balanced emission can be obtained for the entire plurality of light emitting layers.

[0105] In the light emitting device shown in FIGS. 3(A) and 3(B), the first light emitting layer 115a, the second light emitting layer 115b, and the third light emitting layer 115c are illustrated as having a common anode 101 below, but are not limited thereto. For example, the first light emitting layer 115a, the second light emitting layer 115b, and the third light emitting layer 115c may each independently have an anode 101 with a different film thickness below. For example, as a configuration of an anode 101 with different film thicknesses, the film thickness of the anode 101 can be increased in the order of the first light emitting layer 115a, the second light emitting layer 115b, and the third light emitting layer 115c.

[0106] In the light emitting device shown in FIGS. 3(A) and 3(B), since a common hole transporting layer 113 is used in each light emitting layer, a configuration for adjusting the optical distance according to the film thickness of the anode 101 is one of the useful configurations for improving the device characteristics of each light emitting layer.

[0107] Note that the configurations shown in this embodiment can be appropriately combined with the configurations shown in other embodiments or examples.

[0108] (Embodiment 3) ​​In this embodiment, a light-emitting device fabricated by applying a light-emitting element, which is one aspect of the present invention, will be described with reference to FIG. 4. First, the light-emitting device 250 shown in FIG. 4(A) will be described below.

[0109] FIGS. 4(A) and 4(B) are cross-sectional views of a light-emitting device 250 and a light-emitting device 260 each having a first light-emitting layer to a third light-emitting layer between a cathode and an anode. First, the light-emitting device 250 shown in FIG. 4(A) will be described below.

[0110] First, the light-emitting device 250 shown in FIG. 4(A) will be described below.

[0111] The light-emitting device 250 is a so-called bottom-emission structure light-emitting device capable of extracting light from the substrate 200 side (the arrow side shown in FIG. 4(A)). First, the light-emitting device 250 shown in FIG. 4(A) will be described below.

[0112] The light-emitting device 250 has anodes 201a, 201b, and 201c that are separated into island shapes on the substrate 200. The substrate 200 can be made of the materials shown for the substrate 100 in Embodiment 1. The anodes 201a, 201b, and 201c can be made of the materials shown for the anode 101 in Embodiment 1. Also, the anodes 201a, 201b, and 201c may have different thicknesses for each element that emits a different color. In the light-emitting device 250, since it is a bottom-emission structure light-emitting device, the anodes 201a, 201b, and 201c are preferably formed using a material (e.g., ITO, etc.) that has translucency in visible light. The light-emitting device 250 has anodes 201a, 201b, and 201c that are separated into island shapes on the substrate 200. The substrate 200 can be made of the materials shown for the substrate 100 in Embodiment 1. The anodes 201a, 201b, and 201c can be made of the materials shown for the anode 101 in Embodiment 1. Also, the anodes 201a, 201b, and 201c may have different thicknesses for each element that emits a different color. In the light-emitting device 250, since it is a bottom-emission structure light-emitting device, the anodes 201a, 201b, and 201c are preferably formed using a material (e.g., ITO, etc.) that has translucency in visible light. The light-emitting device 250 has anodes 201a, 201b, and 201c that are separated into island shapes on the substrate 200. The substrate 200 can be made of the materials shown for the substrate 100 in Embodiment 1. The anodes 201a, 201b, and 201c can be made of the materials shown for the anode 101 in Embodiment 1. Also, the anodes 201a, 201b, and 201c may have different thicknesses for each element that emits a different color. In the light-emitting device 250, since it is a bottom-emission structure light-emitting device, the anodes 201a, 201b, and 201c are preferably formed using a material (e.g., ITO, etc.) that has translucency in visible light. The light-emitting device 250 has anodes 201a, 201b, and 201c that are separated into island shapes on the substrate 200. The substrate 200 can be made of the materials shown for the substrate 100 in Embodiment 1. The anodes 201a, 201b, and 201c can be made of the materials shown for the anode 101 in Embodiment 1. Also, the anodes 201a, 201b, and 201c may have different thicknesses for each element that emits a different color. In the light-emitting device 250, since it is a bottom-emission structure light-emitting device, the anodes 201a, 201b, and 201c are preferably formed using a material (e.g., ITO, etc.) that has translucency in visible light. The light-emitting device 250 has anodes 201a, 201b, and 201c that are separated into island shapes on the substrate 200. The substrate 200 can be made of the materials shown for the substrate 100 in Embodiment 1. The anodes 201a, 201b, and 201c can be made of the materials shown for the anode 101 in Embodiment 1. Also, the anodes 201a, 201b, and 201c may have different thicknesses for each element that emits a different color. In the light-emitting device 250, since it is a bottom-emission structure light-emitting device, the anodes 201a, 201b, and 201c are preferably formed using a material (e.g., ITO, etc.) that has translucency in visible light. The light-emitting device 250 has anodes 201a, 201b, and 201c that are separated into island shapes on the substrate 200. The substrate 200 can be made of the materials shown for the substrate 100 in Embodiment 1. The anodes 201a, 201b, and 201c can be made of the materials shown for the anode 101 in Embodiment 1. Also, the anodes 201a, 201b, and 201c may have different thicknesses for each element that emits a different color. In the light-emitting device 250, since it is a bottom-emission structure light-emitting device, the anodes 201a, 201b, and 201c are preferably formed using a material (e.g., ITO, etc.) that has translucency in visible light. The light-emitting device 250 has anodes 201a, 201b, and 201c that are separated into island shapes on the substrate 200. The substrate 200 can be made of the materials shown for the substrate 100 in Embodiment 1. The anodes 201a, 201b, and 201c can be made of the materials shown for the anode 101 in Embodiment 1. Also, the anodes 201a, 201b, and 201c may have different thicknesses for each element that emits a different color. In the light-emitting device 250, since it is a bottom-emission structure light-emitting device, the anodes 201a, 201b, and 201c are preferably formed using a material (e.g., ITO, etc.) that has translucency in visible light. The light-emitting device 250 has anodes 201a, 201b, and 201c that are separated into island shapes on the substrate 200. The substrate 200 can be made of the materials shown for the substrate 100 in Embodiment 1. The anodes 201a, 201b, and 201c can be made of the materials shown for the anode 101 in Embodiment 1. Also, the anodes 201a, 201b, and 201c may have different thicknesses for each element that emits a different color. In the light-emitting device 250, since it is a bottom-emission structure light-emitting device, the anodes 201a, 201b, and 201c are preferably formed using a material (e.g., ITO, etc.) that has translucency in visible light.

[0113] The light-emitting device 250 also has partition walls 251a, 251b, 251c, and 251d. The partition wall 251a covers one end of the anode 201a. Also, the partition wall 251b covers the other end of the anode 201a and one end of the anode 201b. Also, the partition wall 251c covers the other end of the anode 201b and one end of the anode 201c. The light-emitting device 250 also has partition walls 251a, 251b, 251c, and 251d. The partition wall 251a covers one end of the anode 201a. Also, the partition wall 251b covers the other end of the anode 201a and one end of the anode 201b. Also, the partition wall 251c covers the other end of the anode 201b and one end of the anode 201c. The light-emitting device 250 also has partition walls 251a, 251b, 251c, and 251d. The partition wall 251a covers one end of the anode 201a. Also, the partition wall 251b covers the other end of the anode 201a and one end of the anode 201b. Also, the partition wall 251c covers the other end of the anode 201b and one end of the anode 201c. The partition wall 251d covers the other end of the anode 201b and one end of the anode 201c. The partition walls 251a, 251b, 251c, and 251d are made of an organic resin or As the organic resin, for example, polyimide resin, Polyamide resin, acrylic resin, siloxane resin, epoxy resin, or phenolic resin Examples of inorganic insulating materials include silicon oxide and silicon oxynitride. This makes it easier to manufacture the partition walls 251a, 251b, 251c, and 251d. Therefore, it is particularly preferable to use a photosensitive resin.

[0114] The light emitting device 250 includes anodes 201a, 201b, and 201c and partitions 251a and 25 The hole injection layer 211 is formed on the first, second, and third layers 251b, 251c, and 251d. The materials shown for the hole-injection layer 111 in embodiment 1 can be used.

[0115] The light emitting device 250 further includes a first hole injection layer 211, which is separated into islands. The semiconductor device has a hole transport layer 213a, a second hole transport layer 213b, and a third hole transport layer 213c. In addition, the first hole transport layer 213a, the second hole transport layer 213b, and the third hole transport layer A first light-emitting layer 215a, a second light-emitting layer 215b, and a third light-emitting layer 213c are disposed on the first light-emitting layer 215a, the second light-emitting layer 215b, and the third light-emitting layer 213c, respectively. The first hole transport layer 213a, the second hole transport layer 213b, the third hole transport layer 215c, The hole transport layer 213c, the first light-emitting layer 215a, the second light-emitting layer 215b, and the third light-emitting layer 215c are 15c are the first hole transport layer 113a and the second hole transport layer 113b shown in the first embodiment. 13b, the third hole transport layer 113c, the first light emitting layer 115a, the second light emitting layer 115b, and and the materials shown in the third light-emitting layer 115c can be used.

[0116] In addition, the first light-emitting layer 215a has, similarly to the first light-emitting layer 115a shown in FIG. 1(A), a first phosphorescent material, a first electron transporting material, and a first hole transporting material. Also, the second light-emitting layer 215b has, similarly to the second light-emitting layer 115b shown in FIG. 1(A), a second phosphorescent material, a second electron transporting material, and a second hole transporting material. Further, the third light-emitting layer 215c has, similarly to the third light-emitting layer 115c shown in FIG. 1(A), a fluorescent material and a third electron transporting material. However, in FIG. 4(A), to avoid complication of the figure, the first phosphorescent material, the first electron transporting material, the first hole transporting material, the second phosphorescent material, the second electron transporting material, the second hole transporting material, the fluorescent material, and the third electron transporting material are omitted from the illustration.

[0117] In addition, the light-emitting device 250 has an electron transporting layer 217 on the first light-emitting layer 215a, the second light-emitting layer 215b, and the third light-emitting layer 215c. Also, the electron transporting layer 217 has an electron injection layer 219 on it. Further, the electron injection layer 219 has a cathode 203 on it. The electron transporting layer 2 17 can use the materials shown in the electron transporting layer 117 shown in Embodiment 1. The electron injection layer 219 can use the materials shown in the electron injection layer 119 shown in Embodiment 1. The cathode 203 can use the materials shown in the cathode 103 shown in Embodiment 1. Also, in the light-emitting device 250, since it is a light-emitting device with a bottom emission structure, the cathode 203 is preferably formed using a material having particularly high reflectivity (for example, aluminum or the like).

[0118] In FIG. 4(A), a configuration in which the anode is disposed below and the cathode is disposed above will be described. However, it is not limited to this. For example, a configuration in which the anode is disposed above and the cathode is disposed below may be used. In this case, the stacking order of the hole injection layer, hole transport layer, light-emitting layer, electron injection layer, and electron transport layer between the anode and the cathode may be reversed.

[0119] The first light-emitting layer 215a, the second light-emitting layer 215b, and the third light-emitting layer 2 15c of the light-emitting device 250 are provided in contact with the electron transport layer 217, and the material forming the electron transport layer 217 has a triplet excitation energy level lower than the triplet excitation energy levels of the electron-transporting material contained in the first light-emitting layer 215a and the second electron-transporting material contained in the second light-emitting layer 215b. Thus, each light-emitting element included in the light-emitting device 250 has an optimal element configuration even when each light-emitting layer uses a common electron transport layer, resulting in a low driving voltage, high current efficiency, or long life. Therefore, a light-emitting device 250 with low power consumption or long life can be provided. In addition, since a common electron transport layer is used, a highly productive light-emitting device 250 can be provided.

[0120] Next, the light-emitting device 260 shown in FIG. 4(B) will be described below.

[0121] The light-emitting device 260 is a modified example of the light-emitting device 250 and is a so-called top-emission structure light-emitting device capable of extracting light from the arrow side shown in FIG. 4(B).

[0122] Further, the light-emitting device 260 has reflective electrodes 253 a, 253b, 253c separated into island shapes on the substrate 200. Further, on the reflective electrodes 253a, 253b, 253c, It has anodes 201a, 201b, and 201c that are separated into island shapes. The light-emitting device 260 In the case of, since it is a top-emission structure light-emitting device, the reflective electrodes 253a, 253 b, 253c are preferably formed using a reflective material (for example, aluminum or silver, etc.).

[0123] Also, the light-emitting device 260 has partition walls 251a, 251b, 251c, 251d. The partition wall 251a covers one end of the reflective electrode 253a and the anode 201a. Also, the partition wall 25 1b covers the other end of the reflective electrode 253a and the anode 201a, and one end of the reflective electrode 253b and the anode 201b. Also, the partition wall 251c covers the other end of the reflective electrode 253b and the anode 201 b, and one end of the reflective electrode 253c and the anode 201c. Also, the partition wall 251d covers the other end of the reflective electrode 253c and the anode 201c.

[0124] Also, the light-emitting device 260 has a hole injection layer 211 on the anodes 201a, 201b, 201c and the partition walls 251a, 25 1b, 251c, 251d.

[0125] Also, the light-emitting device 260 has a first hole transport layer 213a, a second hole transport layer 213b, and a third hole transport layer 213c that are separated into island shapes respectively on the hole injection layer 211 . Also, on the first hole transport layer 213a, the second hole transport layer 213b, and the third hole transport layer 213c, there are a first light-emitting layer 215a, a second light-emitting layer 215b, and a third light-emitting layer 215c respectively.

[0126] Note that the first light-emitting layer 215a is the same as the first light-emitting layer 115a shown in FIG. 1(A), and the first ​​​It has a phosphorescent material of 1, a first electron transporting material, and a first hole transporting material. Also , the second light emitting layer 215b has, similarly to the second light emitting layer 115b shown in Fig. 1(A), a second phosphorescent material, a second electron transporting material, and a second hole transporting material. Also, the third light emitting layer 215c has, similarly to the third light emitting layer 115c shown in Fig. 1(A), a fluorescent material and a third electron transporting material. However, in Fig. 4(B), to avoid complication of the figure, the first phosphorescent material, the first electron transporting material, the first hole transporting material, the second phosphorescent material , the second electron transporting material, the second hole transporting material, the fluorescent material, and the third electron transporting material are omitted from the illustration.

[0127] Also, the light emitting device 260 has an electron transporting layer 217 on the first light emitting layer 215a, the second light emitting layer 215b, and the third light emitting layer 215c. Also, it has an electron injection layer 219 on the electron transporting layer 217. Also, it has a semi-transmissive / semi-reflective electrode 253 that functions as a cathode on the electron injection layer 219. The semi-transmissive / semi-reflective electrode 253 can be formed, for example, by laminating a thin metal film (preferably 2 0 nm or less, more preferably 10 nm or less) and a conductive metal oxide. As the thin metal film, silver, magnesium, or an alloy containing these metal materials can be formed as a single layer or by lamination. As the conductive metal oxide, indium oxide (In2O3), tin oxide (SnO2), zinc oxide (ZnO), ITO, indium zinc oxide (In2O3-ZnO), or a material in which these metal oxide materials contain silicon oxide can be used.

[0128] In the light emitting device 260, since it is a light emitting device with a top emission structure, the reflective electrode A microcavity that utilizes the resonance effect of light is employed between 253a, 253b, 253c and the semi-transmissive and semi-reflective electrode 253, and the light intensity at a specific wavelength can be increased. Note that the function as this microcavity can be adjusted by the material sandwiched between the reflective electrodes 253a, 253b, 253c and the semi-transmissive and semi-reflective electrode 253, or the optical path length or the like. For example, by adjusting the film thicknesses of the anodes 201a, 201b, 201c, the first hole transport layer 213a, the second hole transport layer 213b, and the third hole transport layer 213c, the light intensity of a specific wavelength emitted from each light-emitting layer may be increased. Note that in the light-emitting device 260, a configuration for adjusting the optical path length by the film thicknesses of the first hole transport layer 213a, the second hole transport layer 213b, and the third hole transport layer 213c is illustrated. It is possible to increase the light intensity at a specific wavelength by using a microcavity that utilizes the resonance effect of light. Note that the function as this microcavity can be adjusted by the material sandwiched between the reflective electrodes 253a, 253b, 253c and the semi-transmissive and semi-reflective electrode 253, or the optical path length or the like. For example, by adjusting the film thicknesses of the anodes 201a, 201b, 201c, the first hole transport layer 213a, the second hole transport layer 213b, and the third hole transport layer 213c, the light intensity of a specific wavelength emitted from each light-emitting layer may be increased. Note that in the light-emitting device 260, a configuration for adjusting the optical path length by the film thicknesses of the first hole transport layer 213a, the second hole transport layer 213b, and the third hole transport layer 213c is illustrated. It is possible to increase the light intensity at a specific wavelength by using a microcavity that utilizes the resonance effect of light. Note that the function as this microcavity can be adjusted by the material sandwiched between the reflective electrodes 253a, 253b, 253c and the semi-transmissive and semi-reflective electrode 253, or the optical path length or the like. For example, by adjusting the film thicknesses of the anodes 201a, 201b, 201c, the first hole transport layer 213a, the second hole transport layer 213b, and the third hole transport layer 213c, the light intensity of a specific wavelength emitted from each light-emitting layer may be increased. Note that in the light-emitting device 260, a configuration for adjusting the optical path length by the film thicknesses of the first hole transport layer 213a, the second hole transport layer 213b, and the third hole transport layer 213c is illustrated.

[0129] In addition, in FIG. 4(B), a configuration in which the anode is disposed below and the cathode is disposed above is described, but the present invention is not limited thereto. For example, a configuration in which the anode is disposed above and the cathode is disposed below may be employed. In this case, the lamination order of the hole injection layer, the hole transport layer, the light-emitting layer, the electron injection layer, and the electron transport layer between the anode and the cathode may be reversed. In addition, in FIG. 4(B), a configuration in which the anode is disposed below and the cathode is disposed above is described, but the present invention is not limited thereto. For example, a configuration in which the anode is disposed above and the cathode is disposed below may be employed. In this case, the lamination order of the hole injection layer, the hole transport layer, the light-emitting layer, the electron injection layer, and the electron transport layer between the anode and the cathode may be reversed. In addition, in FIG. 4(B), a configuration in which the anode is disposed below and the cathode is disposed above is described, but the present invention is not limited thereto. For example, a configuration in which the anode is disposed above and the cathode is disposed below may be employed.

[0130] The first light-emitting layer 215a, the second light-emitting layer 215b, and the third light-emitting layer 215c of the light-emitting device 260 are provided in contact with the electron transport layer 217, and the triplet excitation energy level of the material forming the electron transport layer 217 is lower than the triplet excitation energy levels of the electron-transporting material contained in the first light-emitting layer 215a and the second electron-transporting material contained in the second light-emitting layer 215b. Each light-emitting element included in the light-emitting device 260 is configured such that each light-emitting layer shares a common electron transport layer. The first light-emitting layer 215a, the second light-emitting layer 215b, and the third light-emitting layer 215c of the light-emitting device 260 are provided in contact with the electron transport layer 217. The triplet excitation energy level of the material forming the electron transport layer 217 is lower than the triplet excitation energy levels of the electron-transporting material contained in the first light-emitting layer 215a and the second electron-transporting material contained in the second light-emitting layer 215b. Each light-emitting element included in the light-emitting device 260 is configured such that each light-emitting layer shares a common electron transport layer. The triplet excitation energy level of the material forming the electron transport layer 217 is lower than the triplet excitation energy levels of the electron-transporting material contained in the first light-emitting layer 215a and the second electron-transporting material contained in the second light-emitting layer 215b. Even when used, it has an optimal element configuration, resulting in a low driving voltage, high current efficiency , or a long lifespan. Therefore, a light-emitting device 260 with low power consumption or a long lifespan can be provided . Also, since a common electron transport layer is used, a highly productive light-emitting device 260 can be provided

[0131] In addition, the light-emitting device 250 shown in FIG. 4(A) and the light-emitting device 260 shown in FIG. 4(B) illustrate a configuration in which only the light-emitting element is formed on the substrate 200, but it is not limited thereto. For example , a transistor (e.g., a TFT, etc.) is separately formed on the substrate 200, and the transistor is preferably electrically connected to the anodes 201a, 201b, 201c or the reflective electrodes 253a, 253b, 253c

[0132] Here, the manufacturing method of the light-emitting device 250 shown in FIG. 4(A) will be described below

[0133] First, a conductive film is formed on the substrate 200, and the anodes 2 01a, 201b, 201c are formed by processing the conductive film into a desired shape. Next, the partitions 251a, 251b , 201c are formed on the substrate 200 and the anodes 201a, 201b , 201c. Note that the anodes 2 01a, 201b, 201c and the partitions 251a, 251b, 251c, 251d are preferably formed in the manufacturing process of the transistor

[0134] In addition, the structure of the above transistor is not limited, and a top-gate type transistor may be used , or a bottom-gate type transistor such as an inverse staggered type may be used. Also, an n-channel type transistor or a p-channel type transistor may be used. Also, the transistor ​The material used for the transistor is not particularly limited either. For example, a transistor using an oxide semiconductor such as silicon or an In-Ga- Zn-based metal oxide in the channel formation region can be applied. It is possible.

[0135] Next, a hole injection layer 211 is formed on the anodes 201a, 201b, 201c and the partition walls 251a, 251b, 251c, 2 51d. The anodes 201a, 201b, 201c can be formed by a vapor deposition method (including vacuum vapor deposition method), sputtering method, coating method, or inkjet method. Also, the hole injection layer 211 can be formed by methods such as a vapor deposition method (including vacuum vapor deposition method), transfer method, printing method, inkjet method, coating method, etc.

[0136] Next, a first hole transport layer 21 3a is formed at a position in contact with the hole injection layer 211 and overlapping the anode 201a. The first hole transport layer 213a can be formed by a vapor deposition method (including vacuum vapor deposition method), transfer method, printing method, inkjet method, coating method, etc. In the present embodiment, a vapor deposition method is used, and it is formed in a desired region using a vapor deposition mask (also referred to as a metal mask, fine metal mask, or shadow mask).

[0137] Next, a first light-emitting layer 215a is formed on the first hole transport layer 213a. The first light-emitting layer 215a can be formed by methods such as a vapor deposition method (including vacuum vapor deposition method), transfer method, printing method, inkjet method, coating method etc. In the present embodiment, a vapor deposition method is used, and it is formed in a desired region using a vapor deposition mask (also referred to as a metal mask, fine metal mask, or shadow mask). Note that it is preferable to continuously form the first hole transport layer 213a and the first light-emitting layer 215a using the same vapor deposition mask. ​

[0138] Next, a second hole transport layer 213b is formed at a position in contact with the hole injection layer 211 and overlapping with the anode 201b. The second hole transport layer 213b can be formed by the same method as the first hole transport layer 213a. Next, a second hole transport layer 213b is formed at a position in contact with the hole injection layer 211 and overlapping with the anode 201b. The second hole transport layer 213b can be formed by the same method as the first hole transport layer 213a. can be used to form.

[0139] Next, a second light-emitting layer 215b is formed on the second hole transport layer 213b. The second light-emitting layer 215b can be formed by the same method as the first light-emitting layer 215a. Note that the second hole transport layer 213b and the second light-emitting layer 215b are preferably formed continuously using the same evaporation mask. Next, a second light-emitting layer 215b is formed on the second hole transport layer 213b. The second light-emitting layer 215b can be formed by the same method as the first light-emitting layer 215a. Note that the second hole transport layer 213b and the second light-emitting layer 215b are preferably formed continuously using the same evaporation mask. Next, a second light-emitting layer 215b is formed on the second hole transport layer 213b. The second light-emitting layer 215b can be formed by the same method as the first light-emitting layer 215a. Note that the second hole transport layer 213b and the second light-emitting layer 215b are preferably formed continuously using the same evaporation mask. continuously formed.

[0140] Next, a third hole transport layer 213c is formed at a position in contact with the hole injection layer 211 and overlapping with the anode 201c. The third hole transport layer 213c can be formed by the same method as the first hole transport layer 213a. Next, a third hole transport layer 213c is formed at a position in contact with the hole injection layer 211 and overlapping with the anode 201c. The third hole transport layer 213c can be formed by the same method as the first hole transport layer 213a. can be used to form.

[0141] Next, a third light-emitting layer 215c is formed on the third hole transport layer 213c. The third light-emitting layer 215c can be formed by the same method as the first light-emitting layer 215a. Note that the third hole transport layer 213c and the third light-emitting layer 215c are preferably formed continuously using the same evaporation mask. Next, a third light-emitting layer 215c is formed on the third hole transport layer 213c. The third light-emitting layer 215c can be formed by the same method as the first light-emitting layer 215a. Note that the third hole transport layer 213c and the third light-emitting layer 215c are preferably formed continuously using the same evaporation mask. Next, a third light-emitting layer 215c is formed on the third hole transport layer 213c. The third light-emitting layer 215c can be formed by the same method as the first light-emitting layer 215a. Note that the third hole transport layer 213c and the third light-emitting layer 215c are preferably formed continuously using the same evaporation mask. continuously formed.

[0142] Next, an electron transport layer 217 is formed on the hole injection layer 211, the first light-emitting layer 215a, the second light-emitting layer 215b, and the third light-emitting layer 215c, and then an electron injection layer 219 is formed on the electron transport layer 217. The electron transport layer 217 and the electron injection layer 219 can be formed by methods such as vapor deposition (including vacuum vapor deposition), transfer method, printing method, inkjet method, and coating method. Next, an electron transport layer 217 is formed on the hole injection layer 211, the first light-emitting layer 215a, the second light-emitting layer 215b, and the third light-emitting layer 215c, and then an electron injection layer 219 is formed on the electron transport layer 217. The electron transport layer 217 and the electron injection layer 219 can be formed by methods such as vapor deposition (including vacuum vapor deposition), transfer method, printing method, inkjet method, and coating method. including), transfer method, printing method, inkjet method, coating method, etc. can be formed.

[0143] Next, a cathode 203 is formed on the electron injection layer 219. The cathode 203 can be formed using a vapor deposition method (including a vacuum vapor deposition method), a sputtering method, a coating method, or an inkjet method.

[0144] As described above, the light-emitting device 250 shown in FIG. 4(A) can be fabricated.

[0145] Also, the light-emitting device 260 shown in FIG. 4(B) can be formed by adding a step of forming reflection electrodes 253a, 253b, and 253c below the anodes 201a, 201b, and 201c and a step of forming a semi-transmissive / semi-reflective electrode 253 instead of the cathode 203 in addition to the fabrication process of the above-described light-emitting device 250.

[0146] Note that the configuration shown in this embodiment can be appropriately combined with the configurations shown in other embodiments or examples.

[0147] (Embodiment 4) In this embodiment, an example of various electronic devices and lighting devices completed using the light-emitting element or the light-emitting device of one aspect of the present invention will be described with reference to FIG. 5.

[0148] Examples of the electronic device include a television device (also referred to as a television or a television receiver), a monitor for a computer, a digital camera, a digital video camera, a digital photo frame, a mobile phone (also referred to as a mobile phone or a mobile phone device), a portable game machine, a portable information terminal, an audio reproduction device, and a large game machine such as a pachinko machine.

[0149] By fabricating the light-emitting element of one aspect of the present invention on a flexible substrate, a curved surface can be obtained. ​​​​​​An electronic device having a light-emitting part and a lighting device can be realized.

[0150] Further, by forming a pair of electrodes included in the light-emitting element according to one aspect of the present invention using a material having translucency to visible light, an electronic device and a lighting device having a see-through light-emitting part can be realized. can be realized.

[0151] Further, the light-emitting device to which one aspect of the present invention is applied can also be applied to automobile lighting. For example, lighting can be installed on a dashboard, a windshield, a ceiling, or the like.

[0152] FIG. 5(A) shows an example of a television device. The television device 7100 has a display unit 7103 incorporated in a housing 7101. The display unit 7103 can display an image, and a light-emitting device can be used for the display unit 7103. Here, a configuration in which the housing 7101 is supported by a stand 7105 is shown. The housing 7101 incorporates a display unit 7103. The display unit 7103 can display an image, and a light-emitting device can be used for the display unit 7103. Here, a configuration in which the housing 7101 is supported by a stand 7105 is shown. The operation of the television device 7100 can be performed by an operation switch provided in the housing 7101 or a separate remote control operation device 7110. Channel and volume operations can be performed by operation keys 7109 provided in the remote control operation device 7110, and the image displayed on the display unit 7103 can be operated. Further, the remote control operation device 7110 may be provided with a display unit 7107 for displaying information output from the remote control operation device 7110. The housing 7101 incorporates a display unit 7103. The display unit 7103 can display an image, and a light-emitting device can be used for the display unit 7103. Here, a configuration in which the housing 7101 is supported by a stand 7105 is shown.

[0153] The operation of the television device 7100 can be performed by an operation switch provided in the housing 7101 or a separate remote control operation device 7110. Channel and volume operations can be performed by operation keys 7109 provided in the remote control operation device 7110, and the image displayed on the display unit 7103 can be operated. Further, the remote control operation device 7110 may be provided with a display unit 7107 for displaying information output from the remote control operation device 7110. The operation of the television device 7100 can be performed by an operation switch provided in the housing 7101 or a separate remote control operation device 7110. Channel and volume operations can be performed by operation keys 7109 provided in the remote control operation device 7110, and the image displayed on the display unit 7103 can be operated. Further, the remote control operation device 7110 may be provided with a display unit 7107 for displaying information output from the remote control operation device 7110. Channel and volume operations can be performed by operation keys 7109 provided in the remote control operation device 7110, and the image displayed on the display unit 7103 can be operated. Further, the remote control operation device 7110 may be provided with a display unit 7107 for displaying information output from the remote control operation device 7110. Channel and volume operations can be performed by operation keys 7109 provided in the remote control operation device 7110, and the image displayed on the display unit 7103 can be operated. Further, the remote control operation device 7110 may be provided with a display unit 7107 for displaying information output from the remote control operation device 7110. Channel and volume operations can be performed by operation keys 7109 provided in the remote control operation device 7110, and the image displayed on the display unit 7103 can be operated. Further, the remote control operation device 7110 may be provided with a display unit 7107 for displaying information output from the remote control operation device 7110.

[0154] Note that the television device 7100 has a configuration including a receiver, a modem, and the like. The receiver can receive general television broadcasts, and further, can perform wired or wireless communication via the modem. The receiver can receive general television broadcasts, and further, can perform wired or wireless communication via the modem. ​By connecting to a communication network, it is also possible to perform one-way (from sender to receiver) or two-way information communication (such as between a sender and a receiver or between receivers).

[0155] Figure 5(B) shows a computer, which includes a main body 7201, a housing 7202, a display unit 7203, a keyboard 7204, an external connection port 7205, a pointing device 7206, etc. Note that the computer is manufactured by using a light-emitting device for its display unit 7203.

[0156] Figure 5(C) shows a portable gaming machine, which is composed of two housings, a housing 7301 and a housing 7302, and is connected in an openable and closable manner by a connecting portion 7303. A display unit 7304 is incorporated in the housing 7301, and a display unit 7305 is incorporated in the housing 7302. Further, the portable gaming machine shown in Figure 5(C) also includes, among other things, a speaker unit 7306, a recording medium insertion portion 7307, an LED lamp 7308, input means (operation keys 7309, connection terminals 7310, a sensor 73 11 having a function of measuring force, displacement, position, speed, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared rays), a microphone 7312), etc. Of course, the configuration of the portable gaming machine is not limited to the above, and it is sufficient if a light-emitting device is used for at least one or both of the display unit 73 04 and the display unit 7305, and other attached equipment can be provided as appropriate. The portable gaming machine shown in Figure 5(C) has a function of reading a program or data recorded on a recording medium and displaying it on It has a function of sharing information through wireless communication with a portable gaming machine. Note that as shown in Fig. 5(C). The functions of the portable gaming machine are not limited to this, and it can have various functions.

[0157] Fig. 5(D) shows an example of a mobile phone. The mobile phone 7400 includes a housing 7401 In addition to the display unit 7402 incorporated therein, it is equipped with operation buttons 7403, an external connection port 7404, a speaker 7405, a microphone 7406, etc. Note that the mobile phone 7400 is manufactured by using a light-emitting device for the display unit 7402.

[0158] For the mobile phone 7400 shown in Fig. 5(D), information can be input by touching the display unit 7402 with a finger or the like. Also, operations such as making a phone call or creating an email can be performed by touching the display unit 7402 with a finger or the like.

[0159] The screen of the display unit 7402 mainly has three modes. The first is a display mode mainly for displaying images, the second is an input mode mainly for inputting information such as characters, and the third is a display + input mode in which the two modes of the display mode and the input mode are mixed.

[0160] For example, when making a phone call or creating an email, the display unit 7402 can be set to a character input mode mainly for character input, and an input operation of the characters displayed on the screen can be performed. In this case, it is preferable to display a keyboard or number buttons on most of the screen of the display unit 7402.

[0161] Also, by providing a detection device having sensors such as a gyro and an acceleration sensor inside the mobile phone 7400 to detect the inclination, the orientation (vertical or horizontal) of the mobile phone 7400 can be determined, ​​​​​​​​​​ The screen display of the display unit 7402 can be automatically switched.

[0162] Also, the switching of the screen mode is performed by touching the display unit 7402 or operating the operation button 7403 of the housing 7401. Further, it can also be switched according to the type of the image displayed on the display unit 7402. For example, if the image signal displayed on the display unit is video data, it is switched to the display mode, and if it is text data, it is switched to the input mode. operation button 7403 of the housing 7401. Further, it can also be switched according to the type of the image displayed on the display unit 7402. For example, if the image signal displayed on the display unit is video data, it is switched to the display mode, and if it is text data, it is switched to the input mode. data, it is switched to the display mode, and if it is text data, it is switched to the input mode.

[0163] Also, in the input mode, when the signal detected by the optical sensor of the display unit 7402 is detected and there is no input by the touch operation of the display unit 7402 for a certain period, the screen mode may be controlled to be switched from the input mode to the display mode. operation button 7403 of the housing 7401. Further, it can also be switched according to the type of the image displayed on the display unit 7402. For example, if the image signal displayed on the display unit is video data, it is switched to the display mode, and if it is text data, it is switched to the input mode.

[0164] The display unit 7402 can also function as an image sensor. For example, by touching the display unit 7402 with a palm or a finger and imaging a palm print, a fingerprint, etc., personal authentication can be performed. 402 with a palm or a finger and imaging a palm print, a fingerprint, etc., personal authentication can be performed. Also, if a backlight that emits near-infrared light or a sensing light source that emits near-infrared light is used for the display unit, finger veins, palm veins, etc. can also be imaged. source that emits near-infrared light is used for the display unit, finger veins, palm veins, etc. can also be imaged.

[0165] FIG. 5(E) is a desktop lighting device, which includes a lighting unit 7501, an umbrella 7502, a variable arm 7503 , a support column 7504, a base 7505, and a power supply 7506. The desktop lighting device is manufactured by using a light emitting device for the lighting unit 7501. The lighting device also includes a ceiling-fixed lighting fixture or a wall-mounted lighting fixture. or a wall-mounted lighting fixture.

[0166] Note that the configuration shown in this embodiment can be appropriately combined with the configurations shown in other embodiments or examples. combined with the configurations shown in other embodiments or examples. EXAMPLES

[0167] In this example, a 9- [4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation :CzPA) and the host material of the phosphorescent element (the first electron transporting material and the second electron transporting material 2-[3'-(dibenzothiophene-4-yl)biphenyl] nyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II The triplet excitation energy level (T1 level) of the material used in this example was measured. The chemical formula of the material is shown below.

[0168] [ka]

[0169] The T1 level was measured by measuring the phosphorescence of each substance. The measurements were performed at a temperature of 10 K, with 325 nm excitation light irradiated on each substance. For TBPDBq-II, time-resolved measurements were performed using a mechanical chopper. For PA, time-resolved measurements are difficult, so Ir(ppy)3 is added as a sensitizer. The measurements were performed without time resolution. The measurement conditions were as follows: weight ratio of CzPA to 3: Ir(ppy)3 was added in a ratio of 1. The triplet excitation energy level was measured by Calculation from the absorption wavelength is more accurate than calculation from the light wavelength. However, the absorption of the T1 level is extremely Since the emission wavelength is very weak and difficult to measure, we will measure the T The measurement results are shown in Table 1. As shown below.

[0170]

Table 1

[0171] As shown in Table 1, the triplet excitation energy level of CzPA that can be used as an electron transport layer is 0.69 eV lower than that of 2mDBTBPDBq-II that can be used as a host material (the first electron transport material and the second electron transport material) of the phosphorescent element. of the phosphorescent element, and it was confirmed that it is ) also 0.69 eV lower.

Example

[0172] In this example, a light-emitting device (light-emitting device 1, light-emitting device 3, and light-emitting device 5) of one aspect of the present invention, ) and a comparative light-emitting device (comparative light-emitting device 2, comparative light-emitting device 4, and comparative light-emitting device 6) will be described with reference to Fig. 6(A). The chemical formulas of the materials used in this example are shown below. as follows.

[0173]

Chemical formula

[0174]

Chemical formula

[0175] Hereinafter, the manufacturing method of the light-emitting device (light-emitting device 1, light-emitting device 3, and light-emitting device 5) of one aspect of the present invention used in this example, and the comparative light-emitting device (comparative light-emitting device 2, comparative light-emitting device 4, and comparative light-emitting device 6) will be shown.

[0176] Note that light-emitting device 1 and comparative light-emitting device 2 are light-emitting devices that exhibit red light emission, and light-emitting device The light-emitting elements 3 and comparative light-emitting element 4 are light-emitting elements that exhibit green light emission, and the light-emitting elements 5 and comparative light-emitting element 6 are light-emitting elements that exhibit blue light emission.

[0177] (Light-emitting element 1) First, on the substrate 1100, indium tin oxide containing silicon or silicon oxide (ITO-SiO2, hereinafter abbreviated as ITSO) was formed into a film by sputtering to form the anode 1101. The composition of the target used was In2O3:SnO2: SiO2 = 85:10:5 [wt%]. The film thickness of the anode 1101 was 110 nm and the electrode area was 2 mm × 2 mm.

[0178] Next, as a pretreatment for forming a light-emitting element on the substrate 1100, the surface of the substrate was washed with water and baked at 200 °C for 1 hour, and then UV ozone treatment was performed for 370 seconds.

[0179] Thereafter, the substrate was introduced into a vacuum evaporation apparatus whose interior was evacuated to about 10 -4 Pa, and in the heating chamber of the vacuum evaporation apparatus, vacuum baking was performed at 170 °C for 30 minutes, and then the substrate 1100 was allowed to cool for about 30 minutes.

[0180] Next, with the surface on which the anode 1101 is formed facing downward, the substrate 1100 on which the anode 1101 is formed is fixed to a substrate holder provided in the vacuum evaporation apparatus, and the pressure is reduced to about 10 Pa. -4 After that, on the anode 1101, 4,4',4''-( (benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-I (I) ) and molybdenum oxide were co-evaporated to form the hole injection layer 1111. The film thickness thereof was 4 ​Set it to 0 nm, and adjust the ratio of DBT3P-II to molybdenum oxide to 4:2 (= DBT3 P-II: molybdenum oxide) by weight. The co-evaporation method is a deposition method in which deposition is carried out simultaneously from a plurality of evaporation sources in one processing chamber .

[0181] Next, 4-phenyl-4'-(9-phenylfluoren-9 -yl)triphenylamine (abbreviation: BPAFLP) was formed into a film with a thickness of 20 nm on the hole injection layer 1111 to form the hole transport layer 1113

[0182] Next, 2mDBTBPDBq-II, 4,4'-di(1-naphthyl)-4''-(9 -phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB ), and (dipivaloylmethanato)bis(2,3,5-triphenylpyrazinato)iridium (III) (abbreviation: Ir(tppr)2dpm) were co-evaporated to form the light-emitting layer 1115 on the hole transport layer 1113. Here, the weight ratio of 2mDBTBPDBq-II, PCBNBB , and Ir(tppr)2dpm was adjusted to 0.8:0.2:0.06 (= 2mDBTB PDBq-II:PCBNBB:Ir(tppr)2dpm). Also , the thickness of the light-emitting layer 1115 was set to 40 nm .

[0183] In the light-emitting layer 1115, 2mDBTBPDBq-II is an electron-transporting material and functions as a host material. PCBNBB is a hole-transporting material and functions as an assistant ting material. Ir(tppr)2dpm is an organometallic complex containing iridium and functions as a guest material .

[0184] Further, CzPA was formed into a film on the light-emitting layer 1115 to a film thickness of 10 nm, and the electron transport layer 1117 was formed.

[0185] Thereafter, bathophenanthroline (abbreviation: BPhen) was formed into a film on the electron transport layer 1117 to a film thickness of 1 5 nm, and the first electron injection layer 1119a was formed.

[0186] Further, lithium fluoride (LiF) was vapor-deposited on the first electron injection layer 1119a to a film thickness of 1 nm to form the second electron injection layer 1119b.

[0187] Finally, aluminum was vapor-deposited as the cathode 1103 on the second electron injection layer 1119b to a film thickness of 200 nm, thereby fabricating the light-emitting device 1 of this example.

[0188] (Comparative light-emitting device 2) The comparative light-emitting device 2 has a different electron transport layer 1117 compared to the light-emitting device 1. Specifically, the electron transport layer 1117 of the comparative light-emitting device 2 uses 2mD BTBPDBq-II instead of CzPA used in the light-emitting device 1. The film thickness of 2mDBTBPDBq-II was 10 nm as well.

[0189] For the comparative light-emitting device 2, the structure other than the electron transport layer 1117 was fabricated in the same manner as the light-emitting device 1.

[0190] (Light-emitting device 3) The light-emitting device 3 has a different light-emitting layer 1115 compared to the light-emitting device 1. Specifically, the light-emitting layer 1115 of the light-emitting device 3 uses 2mDBTBPDBq-II, PCBNBB, and Ir(tppr)2dpm, instead of those used in the light-emitting device 1, 2mDBTBPDBq-II, PCBNBB , and (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato )iridium(III) (abbreviation: Ir(tBuppm)2(acac)) was used.

[0191] Also, the light-emitting layer 1115 of the light-emitting element 3 was formed by co-evaporating 2mDBTBPDBq-II, PCBNBB , and Ir(tBuppm)2(acac). Here, 2mDBT The weight ratio of BPDBq-II, PCBNBB, and Ir(tBuppm)2(acac) was , 0.8:0.2:0.06 (= 2mDBTBPDBq-II:PCBNBB:Ir(t Buppm)2(acac)) and adjusted. Also, the film thickness of the light-emitting layer 111 5 of the light-emitting element 3 was set to 40 nm.

[0192] In the light-emitting layer 1115 of the light-emitting element 3, 2mDBTBPDBq-II is an electron transport material and functions as a host material. Also, PCBNBB is a hole transport material and functions as an assist material. Also, Ir(tBuppm)2(acac) is an organic metal complex containing iridium and functions as a guest material.

[0193] For the light-emitting element 3, the structure other than the light-emitting layer 1115 was fabricated in the same manner as the light-emitting element 1 .

[0194] (Comparative light-emitting element 4) The comparative light-emitting element 4 has different light-emitting layer 1115 and electron transport layer 1117 compared to the light-emitting element 1 . Specifically, the light-emitting layer 1115 of the comparative light-emitting element 4 uses 2mDBT Instead of BPDBq-II, PCBNBB, and Ir(tppr)2dpm used in the light-emitting element 1, 2mDBT BPDBq-II, PCBNBB, and Ir(tBuppm)2(acac) were used. In addition, for the electron transport layer 1117 of the comparative light-emitting element 4, 2mDBTBPDBq-II was used instead of CzPA used in the light-emitting element 1. , 2mDBTBPDBq-II was used.

[0195] In addition, for the light-emitting layer 1115 of the comparative light-emitting element 4, 2mDBTBPDBq-II, PCBN BB, and Ir(tBuppm)2(acac) were co-evaporated and formed. Here, 2mD The weight ratios of BTBPDBq-II, PCBNBB, and Ir(tBuppm)2(acac) were adjusted to 0.8:0.2:0.06 (= 2mDBTBPDBq-II:PCBNBB:Ir (tBuppm)2(acac)). In addition, the film thickness of the light-emitting layer 1115 of the comparative light-emitting element 4 was set to 40 nm.

[0196] In addition, the film thickness of the electron transport layer 1117 of the comparative light-emitting element 4 was set to 10 nm.

[0197] Note that for the comparative light-emitting element 4, the structure other than the light-emitting layer 1115 and the electron transport layer 1117 was fabricated in the same manner as the light-emitting element 1.

[0198] (Light-emitting element 5) The light-emitting element 5 has a different light-emitting layer 1115 compared to the light-emitting element 1. Specifically, the light-emitting layer 1115 of the light-emitting element 5 uses CzPA and N,N'-bis(3-methyl phenyl)-N,N'-bis〔3-(9-phenyl-9H-fluoren-9-yl)phenyl〕-pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn) instead of 2mDBTBPDBq-II, PCBNBB, and Ir(tppr)2dpm used in the light-emitting element 1.

[0199] In addition, the light-emitting layer 1115 of the light-emitting element 5 contains CzPA and 1,6mMemFLPAPrn , were co-evaporated and formed. Here, the weight ratio of CzPA and 1,6mMemFLPAPrn was adjusted to be 1:0.05 (= CzPA:1,6mMemFLPAPrn). Also, the film thickness of the light-emitting layer 1115 of the light-emitting element 5 was set to 25 nm.

[0200] In the light-emitting layer 1115 of the light-emitting element 5, CzPA is an electron-transporting material and functions as a host material. Also, 1,6mMemFLPAPrn is a fluorescent material and functions as a guest material.

[0201] Regarding the light-emitting element 5, the structure other than the light-emitting layer 1115 was fabricated in the same manner as the light-emitting element 1.

[0202] (Comparative light-emitting element 6) The comparative light-emitting element 6 has different light-emitting layer 1115 and electron-transporting layer 1117 compared to the light-emitting element 1. Specifically, the light-emitting layer 1115 of the comparative light-emitting element 6 uses CzPA and 1,6mMemFLPAPrn instead of 2mDBTBPDBq-II, PCBNBB, and Ir(tppr)2dpm used in the light-emitting element 1. Also, for the electron-transporting layer 1117 of the comparative light-emitting element 6, 2mDBTBPDBq-II is used instead of CzPA used in the light-emitting element 1.

[0203] Also, the light-emitting layer 1115 of the comparative light-emitting element 6 was formed by co-evaporating CzPA and 1,6mMemFLPAPrn. Here, the weight ratio of CzPA and 1,6mMemFLPAPrn was adjusted to be 1:0.05 (= CzPA:1,6mMemFLPAPrn). Also, the film thickness of the light-emitting layer 1115 of the comparative light-emitting element 6 was set to 25 nm.

[0204] In the light-emitting layer 1115 of the comparative light-emitting element 6, CzPA is an electron-transporting material and functions as a host material. Also, 1,6mMemFLPAPrn is a fluorescent material and functions as a guest material.

[0205] Also, the film thickness of the electron-transporting layer 1117 of the comparative light-emitting element 6 was set to 10 nm.

[0206] Regarding the comparative light-emitting element 6, the structure other than the light-emitting layer 1115 and the electron-transporting layer 1117 was fabricated in the same manner as the light-emitting element 1.

[0207] Also, for the light-emitting elements (light-emitting element 1, light-emitting element 3, and light-emitting element 5 ) of one aspect of the present invention described above, and the comparative light-emitting elements (comparative light-emitting element 2, comparative light-emitting element 4, and comparative light-emitting element 6), the deposition process was entirely carried out using the resistance heating method.

[0208] Thus, the light-emitting elements (light-emitting element 1, light-emitting element 3, and light-emitting element 5) of one aspect of the present invention , and the comparative light-emitting elements (comparative light-emitting element 2, comparative light-emitting element 4, and comparative light-emitting element 6) have the same structure except for the light-emitting layer 1115 and the electron-transporting layer 1117.

[0209] The element structures of the light-emitting elements (light-emitting element 1, light-emitting element 3, and light-emitting element 5) of one aspect of the present invention obtained as described above , and the comparative light-emitting elements (comparative light-emitting element 2, comparative light-emitting element 4, and comparative light-emitting element 6) are shown in Table 2.

[0210]

Table 2

[0211] As shown in Table 2, the light-emitting elements of one aspect of the present invention include phosphorescent materials (light-emitting element 1 and light-emitting element As the host material for (3), 2mDBTBPDBq-II is used, and CzPA is used as the host material for the fluorescent material (light-emitting element 5 ). Also, for the electron transport layers of light-emitting element 1, light-emitting element 3, and light-emitting element 5, common CzPA is used. On the other hand, for the comparative light-emitting elements, 2mDBTBP is used as the host material for the phosphorescent material (comparative light-emitting element 2 and comparative light-emitting element 4), and CzPA is used as the host material for the fluorescent material (comparative light-emitting element 6). Also, for the electron transport layers of comparative light-emitting element 2, comparative light-emitting element 4, and comparative light-emitting element 6 , common 2mDBTBPDBq-II is used. .

[0212] Next, in a glove box under a nitrogen atmosphere, an operation of sealing each of the above-prepared light-emitting elements with a glass substrate so as not to be exposed to the atmosphere (applying a sealing material around the element and performing a heat treatment at 80 °C for 1 hour during sealing) was performed. Then, the operating characteristics of each light-emitting element were measured . The measurement was performed at room temperature (atmosphere maintained at 25 °C).

[0213] The current density-luminance characteristics of light-emitting element 1 and comparative light-emitting element 2 are shown in Fig. 7, the voltage-luminance characteristics are shown in Fig. 8 , the luminance-current efficiency characteristics are shown in Fig. 9, the voltage-current characteristics are shown in Fig. 10, and the emission spectrum is shown in Fig. 11 , respectively.

[0214] The current density-luminance characteristics of light-emitting element 3 and comparative light-emitting element 4 are shown in Fig. 12, the voltage-luminance characteristics are shown in Fig 13, the luminance-current efficiency characteristics are shown in Fig. 14, the voltage-current characteristics are shown in Fig. 15, and the emission spectrum is shown in Fig. 16, respectively.

[0215] The current density-luminance characteristics of light-emitting element 5 and comparative light-emitting element 6 are shown in Fig. 17, the voltage-luminance characteristics are shown in Fig The luminance-current efficiency characteristics are shown in Fig. 18, the voltage-current characteristics in Fig. 20, and the emission spectrum in Fig. 21. These are shown in FIG.

[0216] In addition, in Fig. 7, Fig. 12, and Fig. 17, the horizontal axis represents the current density (mA / cm 2 ) on the vertical axis is the luminance (cd / m 2 8, 13, and 18, the horizontal axis represents voltage ( V, and the vertical axis is luminance (cd / m 2 9, 14, and 19, The horizontal axis is luminance (cd / m 2 ), and the vertical axis represents the current efficiency (cd / A). 20, the horizontal axis represents voltage (V) and the vertical axis represents current (mA). 16 and 21, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit). 11, 16, and 21, the emission spectra of the light-emitting elements are roughly overlapped. It is.

[0217] In addition, the luminance of each light-emitting element is 1000 cd / m 2 Voltage (V) and current density near (mA / cm 2 ), CIE chromaticity coordinates (x, y), current efficiency (cd / A), external quantum efficiency ( %) are shown in Table 3.

[0218] [Table 3]

[0219] As shown in Table 3, the luminance of light-emitting element 1 is 992 cd / m 2 The element characteristics in The luminance is 27 cd / A, the external quantum efficiency is 24%, and the CIE chromaticity coordinates are (x,y) =(0.66, 0.34). The luminance of the comparative light-emitting element 2 was 1103 cd / m2 o As the device characteristics, the current efficiency was 27 cd / A, the external quantum efficiency was 23%, and the C IE chromaticity coordinates were (x, y) = (0.66, 0.34).

[0220] Also, as shown in FIG. 11, the emission spectra of the light-emitting device 1 and the comparative light-emitting device 2 have a peak at 619 nm.

[0221] When the light-emitting device 1 and the comparative light-emitting device 2 were compared as described above, no significant difference in device characteristics was confirmed That is, the electron transport property of the electron transport layer 1117 (CzPA) of the light-emitting device 1 and the electron transport property of the electron transport material (2mDBTBPDBq-II), which is the host material of the phosphorescent material, are very high. Therefore, it was confirmed that the emission excited in the light-emitting layer 1115 does not diffuse to the electron transport layer 1117 side or is difficult to diffuse, that is, the device structure is such that

[0222] Also, as shown in Table 3, as the device characteristics at the luminance of the light-emitting device 3 of 804 cd / m 2 the current efficiency was 91 cd / A, the external quantum efficiency was 26%, and the CIE chromaticity coordinates were (x , y) = (0.43, 0.56). Also, as the device characteristics at the luminance of the comparative light-emitting device 4 of 987 cd / m 2 the current efficiency was 93 cd / A, the external quantum efficiency was 26%, and the CIE chromaticity coordinates were (x, y) = (0.43, 0.56).

[0223] Also, as shown in FIG. 16, the emission spectra of the light-emitting device 3 and the comparative light-emitting device 4 have peaks at 549 nm and 546 nm, respectively

[0224] When the light-emitting device 3 and the comparative light-emitting device 4 were compared as described above, no significant difference in device characteristics was confirmed ​​​​​This is not the case. That is, due to the very high electron transporting property of the electron transport layer 1117 (CzPA) of the light-emitting element 3 and the electron transporting property of the electron transporting material (2mDBTBPDBq-II) which is the host material of the phosphorescent material, it was confirmed that the light emission excited in the light-emitting layer 1115 does not diffuse to the electron transport layer 1117 side or has a structure in which diffusion is difficult. Also, as shown in Table 3, as the device characteristics of the light-emitting element 5 at a luminance of 905 cd / m the current efficiency was 11 cd / A, the external quantum efficiency was 9%, and the CIE chromaticity coordinates were (x, y) = (0.14, 0.19). Also, as the device characteristics of the comparative light-emitting element 6 at a luminance of 1115 cd / m

[0225] the current efficiency was 12 cd / A, the external quantum efficiency was 9%, and the CIE chromaticity coordinates were (x, y) = (0.14, 0.19). 2 As for the device characteristics at In addition, as shown in FIG. 21, the emission spectra of the light-emitting element 5 and the comparative light-emitting element 6 each have peaks at 464 nm and 465 nm. 2

[0226]

[0227]

[0228] When the light-emitting element 5 and the comparative light-emitting element 6 are compared as described above, there are differences in the device characteristics. Specifically, as shown in Table 3 and FIG. 20, there are mainly differences in the voltage-current characteristics. 2 The voltage of the light-emitting element 5 at 905 cd / m is 3.3 V, and the voltage of the comparative light-emitting element 6 at 1 115 cd / m 2 is 3.5 V. Also, as shown in FIG. 20, when the voltage is increased from around 3 V, the current value of the comparative light-emitting element 6 is lower than that of the light-emitting element 5 according to one aspect of the present invention.

[0228] ​​This is because the electron transport layer 1117 of the comparative light-emitting element 6 is an electron This is due to the use of a transport material (2mDBTBPDBq-II). The host material of the dye is a material with electron transporting properties (CzPA) used in the light-emitting layer 1115. This reduces the electron transport property.

[0229] On the other hand, in the light-emitting element 5 according to one embodiment of the present invention, the electron-transporting layer 1117 (CzPA) has an electron-transporting property However, the charge transporting material (2mDBTBPDBq-II), which is the host material of the phosphorescent material, Since it has better electron transport properties than ZnO, it has excellent device characteristics even at a lower driving voltage.

[0230] The configuration shown in this embodiment may be the same as that shown in other embodiments or the configuration shown in other embodiments. It is intended that the present invention can be used in appropriate combination with the above composition. EXAMPLES

[0231] In this example, light-emitting elements (light-emitting elements 7 and 8) of one embodiment of the present invention will be described with reference to FIG. The chemical formulas of the materials used in this example are shown below.

[0232] [ka]

[0233] [ka]

[0234] The light-emitting elements (light-emitting elements 7 and 8) according to one embodiment of the present invention used in this example are described below. The preparation method is shown below.

[0235] The light-emitting element 7 is a light-emitting element that emits red light, and the light-emitting element 8 is a light-emitting element that emits green light. It is a light-emitting element to be shown.

[0236] (Light-emitting element 7) First, indium tin oxide compound (ITSO) containing silicon or silicon oxide was formed into a film by a sputtering method to form an anode 1101. The composition of the target used was In2O3:SnO2:SiO2 = 85:10:5 [wt%]. Also, the film thickness of the anode 1101 was set to 110 nm, and the electrode area was set to 2 mm × 2 mm.

[0237] Next, as a pretreatment for forming a light-emitting element on the substrate 1100, the substrate surface was washed with water and baked at 200 °C for 1 hour, and then UV ozone treatment was performed for 370 seconds.

[0238] After that, the substrate was introduced into a vacuum evaporation apparatus whose internal pressure was reduced to about 10 -4 Pa, and in the heating chamber of the vacuum evaporation apparatus, vacuum baking was performed at 170 °C for 30 minutes, and then the substrate 1100 was allowed to cool for about 30 minutes.

[0239] Next, with the surface on which the anode 1101 is formed facing downward, the substrate 1100 on which the anode 1101 is formed is fixed to a substrate holder provided in the vacuum evaporation apparatus, and 10 Pa or less -4 is reduced in pressure, and then on the anode 1101, 4,4',4''-( (benzene-1,3,5-triyl)tri(dibenzothiophene) ((abbreviation: DBT3P- II) and molybdenum oxide are co-evaporated to form a hole injection layer 1111. The film thickness is 4 0 nm, and the ratio of DBT3P-II to molybdenum oxide is adjusted to 4:2 by weight (= DBT3 P-II: molybdenum oxide).

[0240] Next, on the hole injection layer 1111, 4-phenyl-4'-(9-phenylfluoren-9 -yl)triphenylamine (abbreviation: BPAFLP) was formed into a film with a film thickness of 20 nm to form a hole transport layer 1113.

[0241] Next, 2mDBTBPDBq-II, 4,4'-di(1-naphthyl)-4''-(9 -phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB ), and (dipivaloylmethanato)bis(2,3,5-triphenylpyrazinato)iridium (III) (abbreviation: Ir(tppr)2dpm) were co-evaporated to form a light-emitting layer 1115 on the hole transport layer 1113. Here, the weight ratio of 2mDBTBPDBq-II, PCBNBB, and Ir(tppr)2dpm was adjusted to 0.8:0.2:0.06 (= 2mDBTB PDBq-II:PCBNBB:Ir(tppr)2dpm). Also the film thickness of the light-emitting layer 1115 was set to 40 nm.

[0242] Note that in the light-emitting layer 1115, 2mDBTBPDBq-II is an electron transporting material and functions as a host material. Also, PCBNBB is a hole transporting material and functions as an assistant material. Also, Ir(tppr)2dpm is an organometallic complex containing iridium and functions as a guest material.

[0243] Furthermore, CzPA and 1,6mMemFLPAPrn were co-evaporated on the light-emitting layer 1115 to form an electron transport layer 1117a on the light-emitting layer 1115. Here, CzPA and 1, 6mMemFLPAPrn had a weight ratio of 1:0.05 (= CzPA:1,6mMemFL It was adjusted to be 25 nm.

[0244] Note that the electron transport layer 1117a of the light-emitting element 7 has the same configuration as that used for the light-emitting layer of the light-emitting element 5 and the comparative light-emitting element 6 shown in the previous Example 2. That is, it is the configuration used as the electron transport layer 1117a of the light-emitting element 7 for a light-emitting layer that exhibits blue light emission.

[0245] Thereafter, bathophenanthroline (abbreviation: BPhen) was formed into a film with a film thickness of 1 5 nm on the electron transport layer 1117 to form the first electron injection layer 1119a.

[0246] Furthermore, lithium fluoride (LiF) was deposited on the first electron injection layer 1119a with a film thickness of 1 nm to form the second electron injection layer 1119b.

[0247] Finally, aluminum was deposited as the cathode 1103 on the second electron injection layer 1119b with a film thickness of 200 nm to fabricate the light-emitting element 7 of this example.

[0248] (Light-emitting element 8) The light-emitting element 8 has a different light-emitting layer 1115 compared to the light-emitting element 7. Specifically, the light-emitting layer 1115 of the light-emitting element 8 uses 2mDBTBPDBq-II, PCBNBB, and Ir(tppr)2dpm, and instead uses 2mDBTBPDBq-II, PCBNBB , and Ir(tBuppm)2(acac).

[0249] Also, the light-emitting layer 1115 of the light-emitting element 8 was co-evaporated with 2mDBTBPDBq-II, PCBNBB and Ir(tBuppm)2(acac) and formed on the hole transport layer 1113. ​Here, the weight ratio of 2mDBTBPDBq-II, PCBNBB, and Ir(tBuppm)2(acac) was adjusted to 0.8:0.2:0.06 (= 2mDBTBPDBq-II :PCBNBB:Ir(tBuppm)2(acac)). Also, the film thickness of the light-emitting layer 1115 of the light-emitting element 8 was set to 40 nm.

[0250] In the light-emitting layer 1115 of the light-emitting element 8, 2mDBTBPDBq-II is an electron transport material and functions as a host material. Also, PCBNBB is a hole transport material and functions as an assist material. Also, Ir(tBuppm)2(acac) is an organometallic complex containing iridium and functions as a guest material.

[0251] Also, the electron transport layer 1117a of the light-emitting element 8 has the same configuration as that used in the light-emitting layers of the light-emitting element 5 and the comparative light-emitting element 6 shown in the previous Example 2. That is, it is a configuration in which a light-emitting layer that exhibits blue light emission is used as the electron transport layer 1117a of the light-emitting element 8.

[0252] Regarding the light-emitting element 8, the configuration other than the light-emitting layer 1115 was fabricated in the same manner as the light-emitting element 7.

[0253] Also, in the deposition process of the light-emitting elements (light-emitting element 7 and light-emitting element 8) of one aspect of the present invention described above, the resistance heating method was used for all.

[0254] The element structures of the light-emitting elements (light-emitting element 7 and light-emitting element 8) of one aspect of the present invention obtained as described above are shown in Table 4.

[0255]

Table 4

[0256] As shown in Table 4, for the light-emitting element of one embodiment of the present invention, 2mDBTBPDBq-II is used as the host material of the phosphorescent material (light-emitting elements 7 and 8). Also, for the electron transport layers of light-emitting elements 7 and 8, common CzPA and 1,6mMemFLPAPrn are used.

[0257] Next, in a nitrogen atmosphere glove box, the above-prepared light-emitting elements are sealed with a glass substrate so as not to be exposed to the air (a sealing material is applied around the elements, and heat treatment is performed at 80 °C for 1 hour during sealing). Thereafter, the operating characteristics of each light-emitting element were measured. The measurement was performed at room temperature (atmosphere maintained at 25 °C).

[0258] The current density-luminance characteristics of light-emitting elements 7 and 8 are shown in Fig. 22, the voltage-luminance characteristics are shown in Fig. 23, the luminance-current efficiency characteristics are shown in Fig. 24, the voltage-current characteristics are shown in Fig. 25, and the emission spectrum is shown in Fig. 26, respectively.

[0259] In Fig. 22, the horizontal axis represents the current density (mA / cm 2 ), and the vertical axis represents the luminance (cd / m 2 ). Also, in Fig. 23, the horizontal axis represents the voltage (V), and the vertical axis represents the luminance (cd / m 2 ). In Fig. 24, the horizontal axis represents the luminance (cd / m 2 ), and the vertical axis represents the current efficiency (cd / A). In Fig. 25, the horizontal axis represents the voltage (V), and the vertical axis represents the current (mA). Also, in Fig. 26, the horizontal axis represents the wavelength (nm), and the vertical axis represents the intensity (arbitrary unit).

[0260] Also, the voltage (V) and current density 2 when the luminance of each light-emitting element is around 1000 cd / m ​​(mA / cm 2 ), CIE chromaticity coordinates (x, y), current efficiency (cd / A), external quantum efficiency ( %) are shown in Table 5.

[0261]

Table 5

[0262] As shown in Table 5, as the device characteristics of the light-emitting device 7 at a luminance of 984 cd / m 2 , the current efficiency was 27 cd / A, the external quantum efficiency was 25%, and the CIE chromaticity coordinates were (x, y) = (0.66, 0.34). Also, as the device characteristics of the light-emitting device 8 at a luminance of 948 cd / m , the current efficiency was 76 cd / A, the external quantum efficiency was 23%, and the CIE 2 chromaticity coordinates were (x, y) = (0.44, 0.56).

[0263] Also, as shown in Fig. 26, the emission spectra of the light-emitting device 7 and the light-emitting device 8 each have peaks at 6 20 nm and 548 nm. Also, it can be seen that blue light emission from 1,6mMem FLPAPrn used in the electron transport layer (see Fig. 21) was not observed.

[0264] As described above, for the light-emitting device 7 of one aspect of the present invention, even when a light-emitting layer that exhibits blue light emission is used as the electron transport layer 1117a, device characteristics equivalent to those of the light-emitting device 1 shown in Example 2 were obtained. Also, for the light-emitting device 8 of one aspect of the present invention, even when a light-emitting layer that exhibits blue light emission is used as the electron transport layer 1117a, device characteristics equivalent to those of the light-emitting device 3 shown in Example 2 were obtained.

[0265] Therefore, the host material (CzPA) of the fluorescent material used in the electron transport layer 1117a An electron transporting material (2mDBTBPDBq-I I), which is a host material for a sub-transporting and phosphorescent material, has a high electron transporting property. Therefore, the light-emitting region of this light-emitting device is formed in the region near the hole transporting layer 1113 of the light-emitting layer 1115, and it was confirmed that the light emitted by being excited in the light-emitting layer 1115 does not diffuse to the a side of the electron transporting layer 1117, or has a structure in which diffusion is difficult. In addition, the electron transporting layer 1117a used in the light-emitting device 7 and the light-emitting device 8 contains 1,6mM emFLPAPrn, which is a fluorescent material. However, as shown in FIGS. 22 to 26, it was confirmed that 1,6mMemFLPAPrn, which is a fluorescent material, does not affect the device characteristics.

[0266] Note that the configuration shown in this example can be used in appropriate combination with the configuration shown in other embodiments or the configuration shown in other examples.

Example

[0267] In this example, the light-emitting devices 1, 3, 7, and 8, which are light-emitting devices of one aspect of the present invention fabricated in Examples 2 and 3, and the comparative light-emitting devices 2 and 4, which are comparative light-emitting devices, were subjected to a reliability test. The results of the reliability test are shown in FIGS. 27 (A) and (B).

[0268] FIG. 27(A) shows the reliability test results of the light-emitting device 1, the comparative light-emitting device 2, and the light-emitting device 7, that is, the red devices. Further, FIG. 27(B) shows the reliability test results of the light-emitting device 3, the comparative light-emitting device 4, and the light-emitting device 8, that is, the green devices. Note that in FIGS. 27(A) and (B), the measurement method of the reliability test is to set the initial luminance to 5000 cd / m and the current density 2 is set to ​​Each light-emitting element was driven under certain conditions. The horizontal axis represents the driving time (h) of the element, and the vertical axis represents the normalized luminance (%) when the initial luminance is set to 1 00%. Also, in FIGS. 27(A) and (B), the data of each light-emitting element are substantially overlapped.

[0269] From the results of FIG. 27(A), the normalized luminance of the light-emitting element 1 after 357 hours was 68%. Also, the normalized luminance of the comparative light-emitting element 2 after 357 hours was 68%. Also, the normalized luminance of the light-emitting element 7 after 357 hours was 66%. Also, from the results of FIG. 27(B), the normalized luminance of the light-emitting element 3 after 688 hours was 81%. Also, the normalized luminance of the comparative light-emitting element 4 after 688 hours was 82%. Also, the normalized luminance of the light-emitting element 8 after 688 hours was 80%.

[0270] As described above, the light-emitting element 1 and the light-emitting element 7, which are one aspect of the present invention, had results of a reliability test equivalent to those of the comparative light-emitting element 2. Also, the light-emitting element 3 and the light-emitting element 8, which are one aspect of the present invention, had results of a reliability test equivalent to those of the comparative light-emitting element 4.

[0271] Note that the configuration shown in this embodiment can be used in appropriate combination with the configuration shown in other embodiments or the configuration shown in other examples.

Explanation of Reference Numerals

[0272] 100 Substrate 101 Anode 103 Cathode 111 Hole injection layer 113 Hole transport layer 113a First hole transport layer 113b Second hole transport layer 113c Third hole transport layer 113d Fourth hole transport layer​​​ 115 Light-emitting layer 115a First light-emitting layer 115b Second light-emitting layer 115c Third light-emitting layer 117 Electron transport layer 119 Electron injection layer 121a First phosphorescent material 122a First electron transport material 123a First hole transport material 131a Second phosphorescent material 132a Second electron transport material 133a Second hole transport material 141a Fluorescent material 142a Third electron transport material 200 Substrate 201a Anode 201b Anode 201c Anode 203 Cathode 211 Hole injection layer 213a First hole transport layer 213b Second hole transport layer 213c Third hole transport layer 215a First light-emitting layer 215b Second light-emitting layer 215c Third light-emitting layer 217 Electron transport layer 219 Electron injection layer 250 Light-emitting device 251a Partition wall 251b Partition wall 251c Partition wall 251d Partition wall 253 Semi-transmissive / semi-reflective electrode 253a Reflective electrode 253b Reflective electrode 253c Reflective electrode 260 Light-emitting device 1100 Substrate 1101 Anode 1103 Cathode 1111 Hole injection layer 1113 Hole transport layer 1115 Light-emitting layer 1117 Electron transport layer 1117a Electron transport layer 1119a Electron injection layer 1119b Electron injection layer 7100 Television apparatus 7101 Housing 7103 Display unit 7105 Stand 7107 Display unit 7109 Operation key 7110 Remote control operation unit 7201 Main body 7202 Housing 7203 Display unit 7204 Keyboard 7205 External connection port 7206 Pointing device 7301 Housing 7302 Housing 7303 Connecting part 7304 Display unit 7305 Display unit 7306 Speaker unit 7307 Recording medium insertion part 7308 LED lamp 7309 Operation key 7310 Connection terminal 7311 Sensor 7312 Microphone 7400 Mobile phone 7401 Housing 7402 Display unit 7403 Operation button 7404 External connection port 7405 Speaker 7406 Microphone 7501 Lighting unit 7502 Umbrella 7503 Variable arm 7504 Support column 7505 Base 7506 Power supply

Claims

1. A first light-emitting element including a first light-emitting layer and a first hole transport layer, and a second light-emitting element including a second light-emitting layer and a second hole transport layer, wherein the first light-emitting element and the second light-emitting element include an electron transport layer, the electron transport layer has a region in contact with the cathode side of the first light-emitting layer and a region in contact with the cathode side of the second light-emitting layer, the first hole transport layer has a region in contact with the anode side of the first light-emitting layer, the second hole transport layer has a region in contact with the anode side of the second light-emitting layer, the first light-emitting layer has a phosphorescent material, a first organic compound, and a second organic compound, the second light-emitting layer has a fluorescent material and a third organic compound, the first hole transport layer has a fourth organic compound that is at least one of an aromatic amine compound or a carbazole derivative, the second hole transport layer has a fifth organic compound that is at least one of an aromatic amine compound or a carbazole derivative, the electron transport layer has a sixth organic compound, the first organic compound and the second organic compound form a combination that forms an exciplex, a light-emitting device, wherein an emission spectrum of the exciplex overlaps with an absorption band on the longest wavelength side in an absorption spectrum of the phosphorescent material.

2. A first light-emitting element including a first light-emitting layer and a first hole transport layer, and a second light-emitting element including a second light-emitting layer and a second hole transport layer, wherein the first light-emitting element and the second light-emitting element include an electron transport layer, the electron transport layer has a region in contact with the cathode side of the first light-emitting layer and a region in contact with the cathode side of the second light-emitting layer, the first hole transport layer has a region in contact with the anode side of the first light-emitting layer, the second hole transport layer has a region in contact with the anode side of the second light-emitting layer, the first light-emitting layer has a phosphorescent material, a first organic compound, and a second organic compound, the second light-emitting layer has a fluorescent material and a third organic compound, the first hole transport layer has a fourth organic compound that is at least one of an aromatic amine compound or a carbazole derivative, the second hole transport layer has a fifth organic compound that is at least one of an aromatic amine compound or a carbazole derivative, the electron transport layer has a sixth organic compound, the first organic compound and the second organic compound form a combination that forms an exciplex, The emission spectrum of the excitation complex overlaps with the absorption band on the longest wavelength side in the absorption spectrum of the phosphorescent material. The first organic compound is a nitrogen-containing heteroaromatic compound. The second organic compound is a π-electron-excessive heteroaromatic compound, a light-emitting device.

3. In claim 2, The nitrogen-containing heteroaromatic compound is a π-electron-deficient heteroaromatic compound, a light-emitting device.

4. In claim 2, The π-electron-excessive heteroaromatic compound is a compound having at least one of a carbazole skeleton, a thiophene skeleton, or a furan skeleton, a light-emitting device.

5. In any one of claims 1 to 4, The third organic compound is a compound having an anthracene skeleton, a light-emitting device.

6. In any one of claims 1 to 5, The first light-emitting element exhibits red emission, a light-emitting device.

7. In any one of claims 1 to 5, The first light-emitting element exhibits green emission, a light-emitting device.

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