Light-emitting device

Abstract

A light-emitting element having a plurality of light-emitting layers between a pair of electrodes, each of the plurality of light-emitting layers In this invention, a light-emitting element is provided that has a low driving voltage and high luminous efficiency. [Solution] A light-emitting element comprising a first to third light-emitting layer between the cathode and the anode. The first light-emitting layer comprises a first phosphorescent material and a first electron-transporting material, and the second light-emitting layer The light layer comprises a second phosphorescent material and a second electron transport material, and the third light-emitting layer is fluorescent. It comprises a material and a third electron transport material, and the first to third light-emitting layers are each It is provided in contact with the electron transport layer located on the cathode side, and is a triplet of the material forming the electron transport layer. The excitation energy levels of the first electron transport material and the second electron transport material are triplet excitation energy levels It is lower than the energy level.

Description

[Technical Field]

[0001] One aspect of the present invention involves sandwiching a light-emitting layer, which emits light when an electric field is applied, between a pair of electrodes. A light-emitting element, and a light-emitting device, electronic device, and lighting device having such a light-emitting element. Regarding placement. [Background technology]

[0002] Using an organic compound with characteristics such as thinness, light weight, high-speed response, and DC low-voltage drive as the light-emitting layer The light-emitting element used is expected to have applications in next-generation flat-panel displays. Furthermore, a display device in which light-emitting elements are arranged in a matrix has a visual appearance that is superior to conventional liquid crystal displays. It is believed that its advantage lies in its wide field of view and superior visibility.

[0003] The light-emitting mechanism of a light-emitting element involves applying a voltage by sandwiching a light-emitting layer containing a light-emitting element between a pair of electrodes. As a result, electrons injected from the cathode and holes injected from the anode are emitted at the luminescence center of the luminescent layer. They recombine to form molecular excitons, and when these molecular excitons relax to the ground state, they release energy. It is said to emit light. Two excited states are known: singlet excited state and triplet excited state. Therefore, it is thought that luminescence is possible through either excitation state, and the singlet excitation state (S * ) emits fluorescence, triplet excited state (T * The light emitted from ) is called phosphorescence.

[0004] Regarding such light-emitting elements, in order to improve device characteristics or productivity, the device structure Improvements and material development are actively underway. Furthermore, research is being conducted on organic EL elements as light-emitting devices. Development is progressing vigorously, and efforts to implement full color are intensifying.

[0005] As one method for full-color implementation, for example, there is a method of applying different light-emitting layers to individual pixels . The light-emitting layer is vapor-deposited only on necessary pixels using a shadow mask. In this case, the process is reduced to cut costs, and there is disclosed a configuration 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 Literature

Patent Literature

[0006]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0007] In the case of the configuration described in Patent Document 1, the hole transport layer or the electron transport layer is shared by a plurality of pixels , and thus element characteristics such as driving voltage differ among pixels displaying different colors . Further, in the case of such a configuration, since the hole transport layer or the electron transport layer is common among pixels displaying different colors , an optimal element configuration is not achieved for each pixel, and there is a problem that abnormal element characteristics, for example, an increase in driving voltage or a decrease in reliability occurs in at least any one of the plurality of pixels .

[0008] In view of the above problems, in one aspect of the present invention, there is provided a light-emitting element having a plurality of light-emitting layers between a pair of electrodes , and one object of the present invention is to provide a light-emitting element in which each of the plurality of light-emitting layers has a low driving voltage and high luminous efficiency .

Means for Solving the Problem

[0009] One aspect of the present invention is a light-emitting element comprising a first to third light-emitting layer between a cathode and an anode. The child comprises a first light-emitting layer having a first phosphorescent material and a first electron-transporting material, The second light-emitting layer comprises a second phosphorescent material and a second electron-transporting material, and the third light-emitting layer It comprises a fluorescent material and a third electron transport material, and the first to third light-emitting layers are Each is provided in contact with the electron transport layer located on the cathode side, and is made of a material that forms the electron transport layer. The triplet excitation energy levels of the first electron transport material and the second electron transport material This light-emitting element is characterized by having an excitation energy level lower than the term excitation energy level.

[0010] By configuring the electron transport layer to be in common contact with the first to third light-emitting layers, This can increase productivity during the formation of optical elements. Furthermore, the electron transport layer has a first electron transport property The triplet excitation energy level (T1 level) of the material and the second electron transport material is lower than the T1 level. The electron transport of the first electron transport material and the electron transport of the second electron transport material Due to its high transportability, the light-emitting region of the light-emitting element in one embodiment of the present invention is formed on the hole transport layer side of the light-emitting layer. Therefore, the first and second light-emitting layers influence the low T1 level of the electron transport layer. This results in a device configuration that is not affected by external factors, has a low driving voltage, and high luminous efficiency.

[0011] Another aspect of the present invention comprises a first to third light-emitting layer between the cathode and the anode. A light-emitting element comprising a first light-emitting layer comprising a first phosphorescent material and a first electron-transporting material The second light-emitting layer comprises a second phosphorescent material and a second electron-transporting material, and the third The light-emitting layer comprises 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 transport material is , lower than the triplet excitation energy levels of the first electron transport material and the second electron transport material This is a light-emitting element characterized by [specific feature].

[0012] Thus, the third light-emitting layer is provided in contact with the cathode side of the first and second light-emitting layers. Therefore, the third light-emitting layer is on the first light-emitting layer and the second light-emitting layer, and the electron transport layer It functions as such, and the third light-emitting layer functions as a light-emitting layer. Note that the third light-emitting layer contains The fluorescent material (also called a dopant or guest material) is the first electron transport material. Because the electron transport properties of the second electron transport material are high, on the first light-emitting layer and on the second light-emitting layer Therefore, it does not contribute to light emission. On the other hand, in the third light-emitting layer, light emission is obtained from the fluorescent material. This is because the third light-emitting layer simultaneously possesses the functions of both an electron transport layer and a light-emitting layer, the first On the first light-emitting layer and the second light-emitting layer, it is possible to use them in common as electron transport layers. Therefore, the third light-emitting layer can be used as a light-emitting layer. This can increase productivity during device fabrication.

[0013] Furthermore, one aspect of the present invention relates to a light-emitting device having a light-emitting element, an electronic device having a light-emitting device, and Lighting devices are also included in this category. Therefore, in this specification, a light-emitting device means, This refers to an image display device or a light source (including lighting devices). It also refers to a connector on a light-emitting device. For example, FPC (Flexible Printed Circuit) or TCP Module with (Tape Carrier Package) attached, TCP A module with a printed circuit board already installed, or a light-emitting element with COG (Chip On) All modules with ICs (integrated circuits) directly mounted using the glass method are also light-emitting devices. It shall be included in. [Effects of the Invention]

[0014] One aspect of the present invention is a light-emitting element having a plurality of light-emitting layers between a pair of electrodes. Therefore, in each of the multiple light-emitting layers, a light-emitting element with a low driving voltage and high light-emitting efficiency is provided. It can be provided. Furthermore, it is possible to improve productivity when forming the light-emitting element. can. [Brief explanation of the drawing]

[0015] [Figure 1] A diagram illustrating a light-emitting element according to one embodiment of the present invention. [Figure 2] A diagram illustrating a light-emitting element according to one embodiment of the present invention. [Figure 3] A diagram illustrating a light-emitting element according to one embodiment of the present invention. [Figure 4] A diagram illustrating a light-emitting device using a light-emitting element according to one embodiment of the present invention. [Figure 5] A diagram illustrating an electronic device using a light-emitting element and a light-emitting device, which are aspects of the present invention. [Figure 6] A diagram illustrating the light-emitting element of the embodiment. [Figure 7] This figure shows the current density-luminance characteristics of light-emitting element 1 and comparative light-emitting element 2. [Figure 8] A diagram showing the voltage-luminance characteristics of light-emitting element 1 and comparative light-emitting element 2. [Figure 9] This figure shows the brightness-current efficiency characteristics of light-emitting element 1 and comparative light-emitting element 2. [Figure 10] A diagram showing the voltage-current characteristics of light-emitting element 1 and comparative light-emitting element 2. [Figure 11] This figure shows the emission spectra of light-emitting element 1 and comparative light-emitting element 2. [Figure 12] This figure shows the current density-luminance characteristics of light-emitting element 3 and comparative light-emitting element 4. [Figure 13] A diagram showing the voltage-luminance characteristics of light-emitting element 3 and comparative light-emitting element 4. [Figure 14] This figure shows the brightness-current efficiency characteristics of light-emitting element 3 and comparative light-emitting element 4. [Figure 15] A diagram showing the voltage-current characteristics of light-emitting element 3 and comparative light-emitting element 4. [Figure 16] A figure showing the emission spectra of light-emitting element 3 and comparative light-emitting element 4. [Figure 17] This figure shows the current density-luminance characteristics of light-emitting element 5 and comparative light-emitting element 6. [Figure 18] A figure showing the voltage-luminance characteristics of light-emitting element 5 and comparative light-emitting element 6. [Figure 19] This figure shows the brightness-current efficiency characteristics of light-emitting element 5 and comparative light-emitting element 6. [Figure 20] A diagram showing the voltage-current characteristics of light-emitting element 5 and comparative light-emitting element 6. [Figure 21] This figure shows the emission spectra of light-emitting element 5 and comparative light-emitting element 6. [Figure 22] A diagram showing the current density-luminance characteristics of light-emitting elements 7 and 8. [Figure 23] A diagram showing the voltage-luminance characteristics of light-emitting elements 7 and 8. [Figure 24] A diagram showing the brightness-current efficiency characteristics of light-emitting elements 7 and 8. [Figure 25] A diagram showing the voltage-current characteristics of light-emitting elements 7 and 8. [Figure 26] A figure showing the emission spectra of light-emitting elements 7 and 8. [Figure 27] This figure shows the results of reliability tests for light-emitting elements 1, 3, 7, and 8, and comparative light-emitting elements 2 and 4. [Modes for carrying out the invention]

[0016] The embodiments of the present invention will be described in detail below with reference to the drawings. However, the present invention is as follows The description is not limited to the present invention, and the form and details may not depart from the spirit and scope of the present invention. It is possible to change this in various ways. Therefore, the present invention can be described in the embodiments shown below. It should not be interpreted solely in terms of volume.

[0017] For the sake of ease of understanding, the position, size, and scope of each component shown in the drawings, etc., are as follows: The actual location, size, and range may not be represented. Therefore, the disclosed invention may not reflect the actual location, size, or range. It is not necessarily limited to the location, size, or scope disclosed in drawings, etc.

[0018] In this specification, ordinal numbers such as "1st," "2nd," and "3rd" refer to the constituent elements. This note is added to avoid confusion and does not imply a numerical limitation.

[0019] (Embodiment 1) In this embodiment, the concept and specific details of constructing a light-emitting element, which is one aspect of the present invention, are described. The configuration of a light-emitting element will be described. First, a light-emitting element, which is one embodiment of the present invention, will be shown in Figure We will explain using 1(A) and (B).

[0020] The light-emitting element shown in Figure 1(A) has a light-emitting layer 1 between a pair of electrodes (anode 101 and cathode 103). The luminescent layer 115 has 15, and the luminescent layer 115 has a first phosphorescent material 121a and a first electron transport material 122 A first light-emitting layer 115a containing a, a second phosphorescent material 131a, and a second electron-transporting material 1 A second light-emitting layer 115b containing 32a, a fluorescent material 141a, and a third electron-transporting material 14 It has a third light-emitting layer 115c including 2a.

[0021] Furthermore, 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 located on the cathode 103 side.

[0022] Furthermore, the first light-emitting layer 115a comprises a first phosphorescent material 121a and a first electron-transporting material The configuration may also include 122a and a first hole transport material 123a. The light-emitting layer 115b comprises a second phosphorescent material 131a and a second electron-transporting material 132a, Furthermore, the configuration may also include a second hole-transporting material 133a.

[0023] In the first light-emitting layer 115a, the first electron-transporting material 122a is a host material The first phosphorescent material 121a functions as a guest material (also called a dopant). Furthermore, the first hole-transporting material 123a functions as an assisting material. That is, A first electron transport material 122a that functions as a host material is provided with a first phosphorescent material 121a and The first hole transport material 123a is dispersed in this structure. In this configuration, the second electron transport material 132a functions as a host material, and the second phosphorescent material Material 131a functions as a guest material. Also, the second hole transport material 133a is a It functions as a cyst material; that is, a second electron-transporting material that functions as a host material. A structure in which a second phosphorescent material 131a and a second hole transporting material 133a are dispersed in 132a. It is formed. Furthermore, in the third light-emitting layer 115c, the third electron transport material 142a is H The fluorescent material 141a functions as the main material, while the fluorescent material 141a functions as the guest material. That is, A fluorescent material 141a is dispersed in a third electron-transporting material 142a that functions as a host material. It has a well-structured configuration.

[0024] For example, the first phosphorescent material 121a is a phosphorescent material that exhibits red light emission. It can be used as such. Furthermore, the second phosphorescent material 131a exhibits green light emission. Phosphorescent materials can be used as light-emitting substances. Also, as for the fluorescent material 141a Furthermore, fluorescent materials that exhibit blue light emission can be used as the light-emitting substance. In this context, the maximum emission wavelength of phosphorescent materials exhibiting red light emission is greater than 570 nm, at 740 nm. The maximum emission wavelength of phosphorescent materials that emit green light is less than 500 nm. The maximum emission wavelength of fluorescent materials that emit blue light and have a wavelength of 570 nm or less is 400 nm or higher. It is less than 500 nm.

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

[0026] More specifically, the light-emitting element shown in Figure 1(A) consists of an anode 101 on a substrate 100 and an anode 1 A hole injection layer 111 on 01, a first hole transport layer 113a on the hole injection layer 111, and hole The second hole transport layer 113b on the injection layer 111 and the third hole transport layer on the hole injection layer 111 113c, the first light-emitting layer 115a on the first hole transport layer 113a, and the second hole transport layer The second light-emitting layer 115b on 113b and the third light-emitting layer 11 on the third hole transport layer 113c 5c and on the first light-emitting layer 115a, the second light-emitting layer 115b, and the third light-emitting layer 115c The electron transport layer 117, the electron injection layer 119 on the electron transport layer 117, and the electron injection layer 119 It has a cathode 103.

[0027] Thus, if necessary, layers other than the light-emitting layer 115 and the electron transport layer 117 can be placed between the pair of electrodes. For example, hole-injecting or electron-injecting substances, hole-transporting or electron-transporting substances or a layer containing bipolar material (a material with high electron transport and hole transport properties) is formed. You may do so. However, these are not necessarily required.

[0028] Furthermore, in the light-emitting element shown in Figure 1(A), there is a first hole transport layer 113a and a second hole transport layer The pore transport layer 113b and the third hole transport layer 113c are connected to each light-emitting layer (first light-emitting layer 115a The second light-emitting layer 115b and the third light-emitting layer 115c are respectively arranged However, this configuration is not limited to this one, and the hole transport layer may be formed in common for each light-emitting layer. Good. Also, in the light-emitting element shown in Figure 1(A), the first hole transport layer 113a, the second By adjusting the film thickness of the hole transport layer 113b and the third hole transport layer 113c, The optical distance of the light emitted from the light-emitting layer can be adjusted.

[0029] Furthermore, in the light-emitting element shown in Figure 1(A), the light-emitting layer 115 (first light-emitting layer 115a, The second light-emitting layer 115b and the third light-emitting layer 115c are electron transport layer 117 and electron injection layer 119 and cathode 103 are common. Thus, electron transport layer 117, electron injection layer 11 By using 9 and cathode 103 in common in the light-emitting layer 115, production during light-emitting element formation This can improve performance. Note that the color separation process during the formation of the light-emitting element shown in Figure 1(A) is the first The first hole transport layer 113a, the second hole transport layer 113b, and the third hole transport layer 113c are Formed on the hole injection layer 111, the first light-emitting layer 115a, the second light-emitting layer 115b and the third The light-emitting layer 115c is the first hole transport layer 113a, the second hole transport layer 113b, and It is formed on top of the hole transport layer 113c of 3. In addition, each hole transport layer and each light-emitting layer are formed in a continuous manner. This makes it possible to reduce the number of coats applied. For example, the first hole transport layer 11 3a and the first light-emitting layer 115a are formed in succession, and the second hole transport layer 113b and the second light-emitting layer Layer 115b is formed continuously, and the third hole transport layer 113c and the third light-emitting layer 115c are formed continuously. This is how it is formed. Therefore, the light-emitting element shown in Figure 1(A) is formed by a total of three coats of paint. It is possible.

[0030] Furthermore, the light-emitting element shown in Figure 1(A) consists of a first electron transport material 122a and a second electron transport The electron transport properties of the transportable material 132a are very high. Therefore, the first light-emitting layer 115a and The light-emitting region of the second light-emitting layer 115b is formed by the first hole transport layer 113a and the second hole transport layer 11 It is formed in the region near 3b. Therefore, the first light-emitting layer 115a and the second light-emitting layer 115 The emission from b indicates that the triplet excitation energy level of the electron transport layer 117 is the first electron transport material. Although it is lower than the triplet excitation energy of 122a and the second electron transport material 132a However, it is not affected by the triplet excitation energy levels of the electron transport layer 117, or extremely Therefore, it is less susceptible to the effects.

[0031] In other words, in a light-emitting element according to one aspect of the present invention, a first light-emitting layer 115a, a second light-emitting layer 11 In 5b and the third light-emitting layer 115c, when a common electron transport layer 117 is used, Even so, an optimized element configuration can be achieved in each light-emitting layer, resulting in high productivity, and This makes it possible to realize light-emitting elements with high luminous efficiency.

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

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

[0034] Furthermore, the third light-emitting layer 115c is in the shadow of the first light-emitting layer 115a and the second light-emitting layer 115b. It is located adjacent to pole 103.

[0035] Furthermore, the first light-emitting layer 115a comprises a first phosphorescent material 121a and a first electron-transporting material The configuration may also include 122a and a first hole transport material 123a. The light-emitting layer 115b comprises a second phosphorescent material 131a and a second electron-transporting material 132a, Furthermore, the configuration may also include a second hole-transporting material 133a.

[0036] Furthermore, in Figure 1(B), in addition to the light-emitting layer 115, there is also a hole injection layer 1 between the pair of electrodes. 11, First hole transport layer 113a, Second hole transport layer 113b, Third hole transport layer 113 c and the electron injection layer 119 are formed. However, these may be provided as needed. stomach.

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

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

[0039] Furthermore, the electron transport of the first electron transport material 122a and the second electron transport material 132a Because of its high fluorescence properties, the fluorescent material 141a contained in the third light-emitting layer 115c is the same as the first light-emitting layer 1 15a and the second light-emitting layer 115b do not contribute to light emission. On the other hand, the third light-emitting layer 115 In c, light emission is obtained from the fluorescent material 141a contained in the third light-emitting layer 115c. ru.

[0040] In other words, in a light-emitting element according to one aspect of the present invention, the third light-emitting layer 115c interacts with the electron transport layer to emit light. In order to simultaneously provide the functions of layers, the first light-emitting layer 115a and the second light-emitting layer 115b are Therefore, the third light-emitting layer 115c can be used in common as an electron transport layer, and the third On the hole transport layer 113c, the third light-emitting layer 115c is used as the light-emitting layer. This makes it possible to realize light-emitting elements that are highly productive and have high luminous efficiency. Yes, it is possible. Note that the color separation process during the formation of the light-emitting element shown in Figure 1(B) is for the first hole transport layer 1 13a, the second hole transport layer 113b and the third hole transport layer 113c are connected to the hole injection layer 111. The first light-emitting layer 115a and the second light-emitting layer 115b are formed on top of the first hole transport layer. A third light-emitting layer 115c is formed on 113a and the second hole transport layer 113b, and the first light-emitting layer 115c is formed on the first It is formed on the light layer 115a, the second light-emitting layer 115b, and the third hole transport layer 113c. Furthermore, by forming each hole transport layer and each light-emitting layer in a continuous manner, the number of coats required can be reduced. It is possible. For example, the first hole transport layer 113a and the first light-emitting layer 115a can be formed in succession. Then, a second hole transport layer 113b and a second light-emitting layer 115b are formed in succession, and a third hole transport layer A transmitting layer 113c is formed. Then, the first light-emitting layer 115a, the second light-emitting layer 115b, and A third light-emitting layer 115c is formed on the third hole transport layer 113c. Therefore, a total of three times By coloring the areas as shown, the light-emitting element shown in Figure 1(B) can be formed. Also, in Figure 1(B) The light-emitting element shown omits the step of forming the electron transport layer 117 compared to the light-emitting element shown in Figure 1(A). It becomes possible to abbreviate it.

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

[0042] <Circuit board> The substrate 100 is used as a support for the light-emitting element. Examples of substrates 100 include glass. Materials such as silica, quartz, or plastic can be used. A flexible substrate may also be used. A flexible substrate is a substrate that can be bent (flexible), for example, Plastic substrates made of recarbonate, polyarylate, polyethersulfone, etc. These include films (polypropylene, polyester, polyvinyl fluoride, poly Inorganic vapor-deposited films (made of polyvinyl chloride, etc.) can also be used. Other materials may also be used as long as they function as a support during the manufacturing process.

[0043] <Anode> The anode 101 is formed using one or more types of conductive metals, alloys, conductive compounds, etc. This can be achieved. In particular, it is preferable to use materials with a large work function (4.0 eV or more). For example, indium tin oxide (ITO). indium tin oxide, indium zinc oxide, and oxide containing silicon or silicon oxide. Indium oxide, graphene, gold, platinum, and nickel containing tungsten and zinc oxide. , tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, or metallic materials Examples include nitrides (e.g., titanium nitride). Alternatively, silver, copper, aluminum, and titanium. These are formed into nanowires (or thin wires), and a conductive material (conductive organic material or The anode 101 is formed by forming graphene (or the like) by a coating method or printing method, etc. That's good too.

[0044] <Cathode> The cathode 103 uses one or more types of conductive metals, alloys, conductive compounds, etc. It can be formed. In particular, it is possible to use materials with a small work function (3.8 eV or less). Preferred. For example, elements belonging to Group 1 or Group 2 of the periodic table (e.g., lithium, ce Alkali metals such as calcium, alkaline earth metals such as calcium and strontium, magnesium (e.g., um), alloys containing these elements (e.g., Mg-Ag, Al-Li), europium, Rare earth metals such as ytterbium, alloys containing these rare earth metals, aluminum, silver, etc. are used. It is possible to be there.

[0045] <Hole injection layer and hole transport layer> Hole injection layer 111, first hole transport layer 113a, second hole transport layer 113b, and third Examples of highly hole-transporting materials used in the hole transport layer 113c include 4,4'-bis [N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB or α-N) PD) and N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'- Biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4',4''-tris(calcium biphenyl) Bazole-9-yl)triphenylamine (abbreviation: TCTA), 4,4',4''-tri (N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4', 4''-Tris[N-(3-methylphenyl)-N-phenylamino]triphenylamino (Abbreviation: MTDATA), 4,4'-bis[N-(spiro-9,9'-bifluorene- Aromatic amination of 2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB) and other compounds. Compound, 3-[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9 -Phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenyl Carbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazole-3 Examples include -yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1), etc. Other substances include 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 Carbazole derivatives such as zPA can be used. The substances described here are mainly 10 -6 cm 2 It is a substance with a hole mobility of / Vs or greater. However, the hole mobility is greater than that of electrons. Other substances with high transportability may also be used.

[0046] Furthermore, the hole injection layer 111, the first hole transport layer 113a, the second hole transport layer 113b, and as 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 [PTPDMA](N,N'-bis(4-butyl) Phenyl)-N,N'-bis(phenyl)benzidine (abbreviation: Poly-TPD), etc. High-molecular-weight compounds can also be used.

[0047] Furthermore, the hole injection layer 111, the first hole transport layer 113a, the second hole transport layer 113b, and Accepting materials that can be used in the third hole transport layer 113c include transition gold Examples of group oxides include those belonging to Group 4 of the periodic table. Oxides of metals belonging to Group 8 are preferred. Specifically, molybdenum oxide is particularly preferred. stomach.

[0048] <First light-emitting layer> The first light-emitting layer 115a is a first phosphorescent material 121a (guest material), and the first electron transport The hole transport material 122a (host material) and the first hole transport material 123a (assist material) It has. Furthermore, it is preferable that the first light-emitting layer 115a emits red light.

[0049] Note that the T1 level of the host material (or assisting material) is higher than the T1 level of the guest material. It is also preferable that 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 that contributes to light. This is because it leads to a decrease in luminescence efficiency.

[0050] Furthermore, the first phosphorescent material 121a (guest material), the first electron transport material 122a ( The first hole transport material (assist material) and the first hole transport material 123a (assist material) can form an excited complex. This is a combination in which the emission spectrum of the excited complex is that of the first phosphorescent material 121a (Ges The absorption spectrum of the material overlaps with the emission spectrum of the excited complex, and the peak of the emission spectrum is the first phosphorescence. It is preferable that the wavelength is longer than the peak of the absorption spectrum of material 121a (guest material).

[0051] Here, in order to improve the energy transfer efficiency from the host material to the guest material, the intermolecular transfer The Förster mechanism (dipole-dipole interaction) and Dexter are known as dynamic mechanisms. Considering the mechanism (electron exchange interaction), the emission spectrum of the host material (singlet excited state) When discussing energy transfer from a state, fluorescence spectra and energy from triplet excited states are used. - When discussing migration, use the phosphorescence spectrum and the absorption spectrum of the guest material (more specifically, The overlap with the spectrum in the absorption band on the longest wavelength (lowest energy) side becomes larger. This is preferable.

[0052] However, typically, the fluorescence spectrum of the host material is used to determine the longest wavelength (low energy) of the guest material. It is difficult to superimpose the absorption spectrum in the absorption band on the energy side. This is because If you do this, the phosphorescence spectrum of the host material will have longer wavelengths (lower wavelengths) than the fluorescence spectrum. Because it is located on the energy side, the T1 level of the host material is lower than the T1 level of the phosphorescent compound. This is because it leads to the quenching problem mentioned above. To avoid this, the T1 level of the host material is designed to be higher than the T1 level of the phosphorescent compound. Then, the fluorescence spectrum of the host material shifts to the shorter wavelength (higher energy) side. The fluorescence spectrum shows the absorption band at the longest wavelength (lowest energy) end of the guest material. The fluorescence spectrum of the host material will no longer overlap with that of the guest material. The absorption spectrum in the longest wavelength (lowest energy) absorption band is superimposed on the host material. Maximizing energy transfer from singlet excited states is usually difficult.

[0053] Therefore, the first light-emitting layer 115a of the light-emitting element in one aspect of the present invention is a guest material. A first phosphorescent material 121a (referred to as the first substance) and a first electron transporting host material In addition to material 122a (referred to as the second substance), there is also the first hole-transporting material 123a (the third substance). (This includes) and the host material and the third substance form an excited complex (also called an exciplex). It is preferable that the combination formed is such that the carriers (electrons and During the recombination of (holes), the host material and the third substance form an excited complex.

[0054] As a result, in the light-emitting layer, the fluorescence spectrum of the host material and the fluorescence spectrum of the third material are obtained. The clef is converted into the emission spectrum of the excited complex located at longer wavelengths. To maximize the overlap between the emission spectrum of the activating complex and the absorption spectrum of the guest material, By selecting a host material and a third substance, energy transfer from the singlet excited state can be maximized. It can be enhanced. Furthermore, regarding the triplet excited state, it is the excited complex rather than the host material. It is thought that energy transfer occurs. In one embodiment of the present invention applying such a configuration This method utilizes the overlap between the emission spectrum of the excited complex and the absorption spectrum of the phosphorescent compound. Energy transfer can increase energy transfer efficiency, thus increasing external quantum efficiency. This makes it possible to realize a light-emitting element.

[0055] Furthermore, the first electron transport material 122a (host material) and the first hole transport material 123a When using (assist materials), the carrier balance can be controlled by the mixing ratio. Yes, it is possible. Specifically, the first electron-transporting material 122a:first hole-transporting material 123a = It is preferable to use a weight ratio within the range of 1:9 to 9:1.

[0056] Furthermore, energy transfer between excited complexes (exciton diffusion) is unlikely to occur, as described above. By using an excitation complex, exciton diffusion into the electron transport layer 117 can be prevented.

[0057] For example, the first phosphorescent material 121a that can be used in the first light-emitting layer 115a is Examples include phosphorescent materials having an emission peak at 600 nm to 700 nm. For example, (diisobutyrylmethanato)bis[4,6-bis(3-methylmeth [Iridium(III) (abbreviation: Ir(5mdppm)2(dib) m)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethyl Thanato) Iridium(III) (abbreviation: [Ir(5mdppm)2(dpm)]), Bis [4,6-di(naphthalene-1-yl)pyrimidinato](dipivaloylmethanato)iridi Pyrimidine skeletons like um(III) (abbreviation: [Ir(d1npm)2(dpm)]) Organometallic iridium complexes having (acetylacetonato)bis(2,3,5-triph Iridium(III) (abbreviation: [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) Organometallic iridium having a pyrazine skeleton such as [Ir(Fdpq)2(acac)]) Um complexes, and Tris(1-phenylisoquinolinato-N,C) 2’ Iridium (III) (Abbreviation: [Ir(piq)3]), bis(1-phenylisoquinolinato-N,C) 2’ )stomach Lysium(III) acetylacetonate (abbreviation: [Ir(piq)2(acac)]) Examples include organometallic iridium complexes having a pyridine skeleton, such as the one described above. Organometallic iridium complexes with a pyrimidine skeleton offer outstanding reliability and luminescence efficiency. Therefore, it is particularly preferable. Furthermore, organometallic iridium complexes having a pyrazine skeleton have a high chromaticity. A good red light emission can be obtained.

[0058] As a first electron transport material 122a that can be used in the first light-emitting layer 115a, π-electron-deficient heteroaromatic compounds, such as nitrogen-containing heteroaromatic compounds, are preferred, for example, 2 -(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-oxadiazole-2-yl] Benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazo [Il-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 2,2',2' -(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzoimidazo (Abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1 Polyazols such as -phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II) Heterocyclic compounds having a cycloidal skeleton (oxadiazole derivatives, imidazole derivatives, triadiazole derivatives) (Zol derivatives, etc.) and 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo [f,h]Quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzo Thiofen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation) :2mDBTBPDBq-II), 2-[3'-(9H-carbazole-9-yl)bif [enyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 4 ,6-Bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6m PnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine ( Heterocyclic compounds (pyramidal compounds) having a diazine skeleton, such as abbreviation: 4,6mDBTP2Pm-II Zin derivatives, pyrimidine derivatives, pyridazine derivatives, quinoxaline derivatives, dibenzoquinone (Xaline derivatives, etc.) and 3,5-bis(9H-carbazole-9-yl)phenyl) pyri Zin (abbreviation: 3,5DCzPPy), 1,3,5-tri[(3-pyridyl)phen-3 Heterocyclic compounds having a pyridine skeleton, such as -ylbenzene (abbreviation: TmPyPB) Examples include lysine derivatives, quinoline derivatives, dibenzoquinoline derivatives, etc. However, heterocyclic compounds with a diazine skeleton or a pyridine skeleton are reliable. The properties are good and desirable. In particular, heterocycles having a diazine (pyrimidine or pyrazine) skeleton. The compound exhibits high electron transport properties and contributes to reducing the driving voltage.

[0059] Furthermore, the first hole transport material 123a can be used in the first light-emitting layer 115a. Therefore, π-electron-rich heteroaromatic compounds (for example, carbazole derivatives and indole derivatives) 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'-bifluoren-2-yl)-N-f [phenylamino]biphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenyl Luolen-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3' -(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP) , 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenyl Amine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9 H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-( 1-Naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenyl Amine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl Lu-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBNBB), 9, 9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-I [phenyl]-fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[ 4-(9-phenyl-9H-carbazole-3-yl)phenyl]-spiro-9,9'- Compounds having an aromatic amine skeleton, such as bifluoren-2-amine (abbreviation: PCBASF) For example, 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N -Carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenyl) (nyl)-9-phenylcarbazole (abbreviation: CzTP), 3,3'-bis(9-phenyl Compounds having a carbazole skeleton, such as ru-9H-carbazole (abbreviated as PCCP), and ,4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (Abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H- Fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III) , 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyl Compounds containing a thiophene skeleton, such as dibenzothiophene (abbreviation: DBTFLP-IV) , or 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran)( Abbreviation: DBF3P-II), 4-{3-[3-(9-phenyl-9H-fluorene-9- [phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), etc. Examples include compounds having a furan skeleton. Among those mentioned above, compounds having an aromatic amine skeleton Compounds containing composites or carbazole skeletons are highly reliable and exhibit high hole transport properties. Furthermore, it is preferable because it also contributes to reducing the drive voltage.

[0060] <Second light-emitting layer> The second light-emitting layer 115b is a second phosphorescent material 131a (guest material), and a second electron transport The hole transport material 132a (host material) and the second hole transport material 133a (assist material) It has. Furthermore, it is preferable that the second light-emitting layer 115b exhibits green light emission.

[0061] Furthermore, a second phosphorescent material 131a (guest material), a second electron transport material 132a ( The first material (the assist material) and the second hole transport material 133a (the assist material) can form an excited complex. This combination allows for the emission spectrum of the excited complex to be that of the second phosphorescent material 131a (Ges The absorption spectrum of the material overlaps with that of the excited complex, and the peak of the emission spectrum of the excited complex is the second phosphorescent peak. It is preferable that the wavelength is longer than the peak of the absorption spectrum of material 131a (guest material). Regarding the configuration of the excitation complex, the second light-emitting layer 115a has the same configuration as the first light-emitting layer 115a. This can also be applied to 15b.

[0062] Furthermore, the second electron transport material 132a (host material) and the second hole transport material 133a When using (assist materials), the carrier balance can be controlled by the mixing ratio. Yes, it is possible. Specifically, the ratio of the second electron-transporting material 132a to the second hole-transporting material 133a = It is preferable to use a weight ratio within the range of 1:9 to 9:1.

[0063] Furthermore, energy transfer between excited complexes (exciton diffusion) is unlikely to occur, as described above. By using an excitation complex, exciton diffusion into the electron transport layer 117 can be prevented.

[0064] A second phosphorescent material 131a that can be used in the second light-emitting layer 115b is, for example, Examples include phosphorescent materials having an emission peak in the 520nm to 600nm range. For example, tris(4-methyl-6-phenylpyrimidinato)iridium(I II) (abbreviation: [Ir(mppm)3]), Tris(4-t-butyl-6-phenylpyrylene pyropropyl alcohol) Iridium(III) (abbreviation: [Ir(tBuppm)3]), (acetylated) Setonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation) :[Ir(mppm)2(acac)]), (acetylacetonato)bis(6-tert -Butyl-4-phenylpyrimidinato) Iridium(III) (Abbreviation: [Ir(tBup pm)2(acac)]), (acetylacetonato)bis[4-(2-norbornyl)- 6-Phenylpyrimidinato]iridium(III) (endo-,exo- mixture) (abbreviated) Name: Ir(nbppm)2(acac)), (acetylacetonato)bis[5-methyl- 6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation) :[Ir(mpmppm)2(acac)]), (acetylacetonato)bis(4,6- Diphenylpyrimidina) Iridium(III) (abbreviation: [Ir(dppm)2(aca Organometallic iridium complexes having a pyrimidine skeleton such as (acetylacet) Nato)bis(3,5-dimethyl-2-phenylpyradinato)iridium(III) (abbreviation) :[Ir(mppr-Me)2(acac)]), (acetylacetonato)bis(5- sopropyl-3-methyl-2-phenylpyrazinato)iridium(III) (abbreviation: [I r(mppr-iPr)2(acac)]), and organometallic iridium complexes having a pyrazine skeleton, as well as tris(2-phenylpyridinato-N,C 2’ )iridium(III) ( abbreviation: [Ir(ppy)3]), bis(2-phenylpyridinato-N,C 2’ )iridium m(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 2’ )i ridium(III) (abbreviation: [Ir(pq)3]), bis(2-phenylquinolinato-N ,C 2’ )iridium(III) acetylacetonate (abbreviation: [Ir(pq)2(ac ac)]), and organometallic iridium complexes having a pyridine skeleton. The aforementioned Among these, organometallic iridium complexes having a pyrimidine skeleton are particularly preferable because they are remarkably excellent in reliability and luminous efficiency. Among the above, organometallic iridium complexes having a pyrimidine skeleton are particularly preferable because they are remarkably excellent also 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 exemplified as the first electron transporting material 122a can be used. Further, as for the second hole transporting material 133a that can be used for the second light-emitting layer 115b, the same materials as those exemplified as the first hole transporting material 123a can be used.

[0066] <Third light-emitting layer> The third light-emitting layer 115c is a fluorescent material 141a (guest material), and a third electron transport material It has material 142a (host material). In addition, the third light-emitting layer 115c emits blue light. It is preferable to show this.

[0067] The fluorescent material 141a that can be used in the third light-emitting layer 115c is N,N'- Bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-N,N'-diph Enylpyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis( 3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluorene-9- Il)phenyl]-pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn) N,N'-bis[4-(9H-carbazole-9-yl)phenyl]-N,N'-diph Enylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazeo Lu-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 Lu-N-[4-(10-phenyl-9-antryl)phenyl]-9H-carbazole- 3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra-tert- Tylperylene (abbreviation: TBP), 4-(10-phenyl-9-antryl)-4'-(9 -phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBAPA) Examples include the following. In particular, fluorescent compounds having a pyrene skeleton have high hole-trapping properties. It is preferable due to its superior luminous efficiency and reliability. Also, 1,6FLPAPrn and 1,6mM Condensed aromatic diamine compounds, such as pyrenediamine compounds like emFLPAPrn The material is preferable because it has high hole-trapping properties and excellent luminescence efficiency and reliability.

[0068] As a third electron-transporting material 142a that can be used in the third light-emitting layer 115c, For example, organic compounds containing an anthracene skeleton are preferred. Examples of compounds include 9-[4-(10-phenyl-9-anthracenyl)phenyl ]-9H-carbazole (abbreviation: CzPA), 9-phenyl-3-[4-(10-phenyl Lu-9-antryl)phenyl]-9H-carbazole (abbreviation: PCzPA), 3,6- Diphenyl-9-[4-(10-phenyl-9-antryl)phenyl]-9H-carb Zole (abbreviation: DPCzPA), 9,10-bis(3,5-diphenylphenyl)ant Helical (abbreviation: DPPA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA) ), 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: tB The preferred use of compounds that are electron-transporting but also readily accept holes, such as uDNA. This is possible. In a light-emitting element according to one aspect of the present invention, the third electron-transporting material 142a is an Having a transene skeleton is preferable because it not only has electron transport properties but also readily accepts holes. It's nice.

[0069] <Electron transport layer> The electron transport layer 117 is a layer containing a material with high electron transport properties. The triplet excitation energy levels of the materials forming the first light-emitting layer 115a and the second light-emitting layer Three electron transport materials used in 115b: the first electron transport material 122a and the second electron transport material 132a This material has a lower multiplet excitation energy level. An example of such a material is the third light-emitting layer. Use a material similar to the third electron-transporting material 142a that can be used in 115c. It is possible.

[0070] <Electron injection layer> The electron injection layer 119 is a layer containing a material with high electron injection capacity. Lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2) , alkali metal or alkaline earth metal compounds such as lithium oxide (LiOx) It can also be used. You can use it.

[0071] Alternatively, the electron injection layer 119 may be formed by mixing an organic compound with an electron donor. Composite materials may be used. Such composite materials can donate electrons to organic compounds by electron donors. Because of the resulting phenomenon, it exhibits excellent electron injection and electron transport properties. In this case, as an organic compound Therefore, it is preferable that the material is excellent in transporting the generated electrons, and as the electron donor, Any substance that exhibits electron-donating properties to the compound will suffice. Specifically, alkali metals and alkalis Lithium-earth metals and rare earth metals are preferred, such as lithium, cesium, magnesium, calcium, Examples include erbium and ytterbium. Also, alkali metal oxides and alkaline earth elements. Metal oxides are preferred, including lithium oxide, calcium oxide, and barium oxide. It can also be used. Furthermore, Lewis bases such as magnesium oxide can be used. Organic compounds such as thiafulvalene (abbreviated as TTF) can also be used.

[0072] Furthermore, the hole injection layer 111, the first hole transport layer 113a, and the second hole transport layer 11 3b, third hole transport layer 113c, first light-emitting layer 115a, second light-emitting layer 115b, third The light-emitting layer 115c, electron transport layer 117, and electron injection layer 119 are each deposited by a vapor deposition method (true It can be formed by methods such as vapor deposition, inkjet, and coating.

[0073] Furthermore, the first light-emitting layer 115a, the second light-emitting layer 115b, and the third of the light-emitting element described above The light emitted from the light-emitting layer 115c is emitted from either one or both of the anode 101 and cathode 103. It is taken out to the outside through this. Therefore, the anode 101 and cathode 1 in this embodiment Either one or both of 03 will be a light-transmitting electrode.

[0074] The configuration shown in this embodiment may be combined with the configurations shown in other embodiments or examples as appropriate. They can be combined.

[0075] (Embodiment 2) In this embodiment, a modified example of the light-emitting element according to one aspect of the present invention shown in Figure 1 is shown in Figure 1. The explanation will be given using Figure 2 and Figure 3. Note that the same parts as shown in the previous embodiment, or the same parts as shown in Figure 3, will be explained. Functional parts are denoted by the same symbols, and detailed explanations are omitted.

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

[0077] Furthermore, 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 located on the cathode 103 side.

[0078] Furthermore, the first light-emitting layer 115a comprises a first phosphorescent material 121a and a first electron-transporting material The configuration may also include 122a and a first hole transport material 123a. The light-emitting layer 115b comprises a second phosphorescent material 131a and a second electron-transporting material 132a, Furthermore, the configuration may also include a second hole-transporting material 133a.

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

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

[0081] Next, we will explain the light-emitting element shown in Figure 2(B).

[0082] The light-emitting element shown in Figure 2(B) has a light-emitting layer 1 between a pair of electrodes (anode 101 and cathode 103). The luminescent layer 115 has 15, and the luminescent layer 115 has a first phosphorescent material 121a and a first electron transport material 122 A first light-emitting layer 115a containing a, a second phosphorescent material 131a, and a second electron-transporting material 1 A second light-emitting layer 115b including 32a, and the first light-emitting layer 115a and the second light-emitting layer 115b A third light-emitting layer 1 covers the third light-emitting layer and includes a fluorescent material 141a and a third electron-transporting material 142a. It has 15c and

[0083] Furthermore, the third light-emitting layer 115c is in the shadow of the first light-emitting layer 115a and the second light-emitting layer 115b. It is located adjacent to pole 103.

[0084] Furthermore, the first light-emitting layer 115a comprises a first phosphorescent material 121a and a first electron-transporting material The configuration may also include 122a and a first hole transport material 123a. The light-emitting layer 115b comprises a second phosphorescent material 131a and a second electron-transporting material 132a, Furthermore, the configuration may also include a second hole-transporting material 133a.

[0085] Furthermore, in Figure 2(B), in addition to the light-emitting layer 115, there is also a hole injection layer 1 between the pair of electrodes. 11, First hole transport layer 113a, Second hole transport layer 113b, Fourth hole transport layer 113 d, and the electron injection layer 119 are formed.

[0086] More specifically, the light-emitting element shown in Figure 2(B) consists of an anode 101 on the substrate 100 and an anode 1 A hole injection layer 111 on 01, a fourth hole transport layer 113d on the hole injection layer 111, and a fourth The first hole transport layer 113a on the hole transport layer 113d and the fourth hole transport layer 113d A second hole transport layer 113b and a 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, and the first light-emitting layer 115a, the second The light-emitting layer 115b, and the third light-emitting layer 115c on the fourth hole transport layer 113d, and the third light It has an electron injection layer 119 on the optical layer 115c and a cathode 103 on the electron injection layer 119.

[0087] The light-emitting elements shown in Figures 2(A) and 2(B) differ from the light-emitting elements shown in Figures 1(A) and 1(B) in the following ways: Furthermore, a fourth hole transport layer 113d is provided on the hole injection layer 111. The light-emitting layer 115c does not have a third hole transport layer 113c. That is, the third The light-emitting layer 115c is provided in contact with the fourth hole transport layer 113d. The material that can be used for the hole transport layer 113d is the same material as the third hole transport layer 113c. You can use the fee.

[0088] The fourth hole transport layer 113d is connected to the first light-emitting layer 115a, the second light-emitting layer 115b, and It can be used in common for the light-emitting layer 115c of 3. Therefore, Figure 2(A), (B) The light-emitting element shown is an excellent effect of the light-emitting element of one embodiment of the present invention shown in Figures 1(A) and (B). In addition, productivity during the formation of light-emitting elements can be further increased. The color separation process during the formation of the optical element involves the first hole transport layer 113a and the second hole transport layer 113b. These consist of a first light-emitting layer 115a, a second light-emitting layer 115b, and a third light-emitting layer 115c. Furthermore, by forming each hole transport layer and each light-emitting layer in a continuous manner, the number of coats required can be reduced. This is possible. For example, the first hole transport layer 113a and the first light-emitting layer 115a are formed successively , then the second hole transport layer 113b and the second light-emitting layer 115b are formed successively, and the third light-emitting layer 115c is formed. Accordingly, the light-emitting element shown in FIG. 2(A) can be formed by a total of 3 separate coating processes . In addition, in the separate coating step for forming the light-emitting element shown in FIG. 2(B), the layers are the first hole transpor t layer 113a, the second hole transport layer 113b, the first light-emitting layer 115a, and the second light-emitting layer 1 15b. Further, by forming each hole transport layer and each light-emitting layer successively, the number of separate coating processes can be reduced. For example, the first hole transport layer 113a and the first light-emitting layer 115 a are formed successively, and the second hole transport layer 113b and the second light-emitting layer 115b are formed successively . Accordingly, the light-emitting element shown in FIG. 2(B) can be formed by a total of 2 separate coating processes .

[0089] In addition, in the light-emitting elements shown in FIGS. 2(A) and 2(B), the first light-emitting layer 115a and the secon d light-emitting layer 115b are independently formed in contact with the first hole transport layer 113a and the second hole transpor t layer 113b, respectively. Accordingly, an optimal element configuration can be obtained for each light-emitting laye r, and a light-emitting element with high luminous efficiency can be achieved for each of the light-emitting layers.

[0090] Furthermore, in the light-emitting elements shown in FIGS. 2(A) and 2(B), by adjusting the film thicknesses of the first hole transport layer 113a, the secon d 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 Figure 3(A) has a light-emitting layer 1 between a pair of electrodes (anode 101 and cathode 103). The luminescent layer 115 has 15, and the luminescent layer 115 has a first phosphorescent material 121a and a first electron transport material 122 A first light-emitting layer 115a containing a, a second phosphorescent material 131a, and a second electron-transporting material 1 A second light-emitting layer 115b containing 32a, a fluorescent material 141a, and a third electron-transporting material 14 It has a third light-emitting layer 115c including 2a.

[0093] Furthermore, 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 located on the cathode 103 side.

[0094] Furthermore, the first light-emitting layer 115a comprises a first phosphorescent material 121a and a first electron-transporting material The configuration may also include 122a and a first hole transport material 123a. The light-emitting layer 115b comprises a second phosphorescent material 131a and a second electron-transporting material 132a, Furthermore, the configuration may also include a second hole-transporting material 133a.

[0095] Furthermore, in Figure 3(A), in addition to the light-emitting layer 115, there is also a hole injection layer 1 between the pair of electrodes. 11, a hole transport layer 113, and an electron injection layer 119 are formed.

[0096] More specifically, the light-emitting element shown in Figure 3(A) consists of an anode 101 on the substrate 100 and an anode 1 A hole injection layer 111 on 01, a hole transport layer 113 on the hole injection layer 111, and a hole transport layer 1 13 The first light-emitting layer 115a on top, the second light-emitting layer 115b on top of the hole transport layer 113, and hole The third light-emitting layer 115c on the transport layer 113, the first light-emitting layer 115a, and the second light-emitting layer 115 b, and 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 Figure 3(B) will be explained below.

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

[0099] Furthermore, the third light-emitting layer 115c is in the shadow of the first light-emitting layer 115a and the second light-emitting layer 115b. It is located adjacent to pole 103.

[0100] Furthermore, the first light-emitting layer 115a comprises a first phosphorescent material 121a and a first electron-transporting material The configuration may also include 122a and a first hole transport material 123a. The light-emitting layer 115b comprises a second phosphorescent material 131a and a second electron-transporting material 132a, Furthermore, the configuration may also include a second hole-transporting material 133a.

[0101] Furthermore, in Figure 3(B), in addition to the light-emitting layer 115, there is also a hole injection layer 1 between the pair of electrodes. 11, a hole transport layer 113, and an electron injection layer 119 are formed.

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

[0103] The light-emitting elements shown in FIGS. 3A and 3B differ from the light-emitting elements shown in FIGS. 1A and 1B in that a hole transport layer 113 is provided on the hole injection layer 111. That is, the hole transport layer 113 can serve 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. Further, the material that can be used for the hole transport layer 113 can be the same material as that used for the third hole transport layer 113c. Therefore, the light-emitting elements shown in FIGS. 3A and 3B, in addition to providing the excellent effects of the light-emitting element according to one aspect of the present invention shown in FIGS. 1A and 1B, can further improve productivity during the formation of the light-emitting element. Note that the separate coating step for forming the light-emitting element shown in FIG. 3A is performed for the first light-emitting layer 115a and the second light-emitting layer 115b and the third light-emitting layer 115c, resulting in a total of 3 coating steps. In addition, the separate coating step for forming the light-emitting element shown in FIG. 3B is performed for the first light-emitting layer 115a and the second light-emitting layer 115b and the third light-emitting layer 115c, resulting in a total of 3 coating steps. Further, for the light-emitting element shown in FIG. 3(B) the separate coating step for forming the light-emitting element is performed for the first light-emitting layer 115a and the second light-emitting layer 11 5b, resulting in a total of 2 coating steps.

[0104] However, in the element configurations shown in FIGS. 3A and 3B, 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, so that for any one or two of the first light-emitting layer 115a, the second light-emitting layer 115b, and the third light-emitting layer 115c, there is a possibility that element characteristics may deteriorate. However, the element characteristics If productivity is the priority, the configurations shown in Figures 3(A) and (B) may be applied. Furthermore, in the configuration shown in Figures 3(A) and (B), the first electron transport material 122a and Furthermore, the electron transport properties of the second electron transport material 132a and the third light-emitting layer 115c are very high. Therefore, even when a common hole transport layer is used in each light-emitting layer, the element on the electron transport layer side Because there is no or very little degradation in sub-characteristics, a balanced emission is achieved across multiple light-emitting layers. It can be used as an optical element.

[0105] Furthermore, in the light-emitting element shown in Figures 3(A) and (B), the first light-emitting layer 115a, the second The light-emitting layer 115b and the third light-emitting layer 115c use a common anode 101 at the bottom. While examples of formation have been given, the invention is not limited to these. For example, the first light-emitting layer 115a, the second light-emitting layer The light layer 115b and the third light-emitting layer 115c each independently emit an anode 101 of a different thickness. The configuration may also be located at the bottom. For example, the configuration of the anode 101 with different film thicknesses is: The film of the anode 101 is formed in the order of the first light-emitting layer 115a, the second light-emitting layer 115b, and the third light-emitting layer 115c. The thickness can be increased.

[0106] In the light-emitting devices shown in Figures 3(A) and (B), a common hole transport layer 1 is present in each light-emitting layer. Since 13 is used, the configuration that adjusts the optical distance by the film thickness of the anode 101 is, each light-emitting layer This is one of the configurations useful for improving the characteristics of the element.

[0107] The configuration shown in this embodiment may be combined with the configurations shown in other embodiments or examples as appropriate. They can be combined.

[0108] (Embodiment 3) In this embodiment, a light-emitting device is fabricated by applying a light-emitting element according to one aspect of the present invention. Let's explain using Figure 4.

[0109] Figures 4(A) and (B) show a light-emitting device having a first to third light-emitting layer between the cathode and anode. This is a cross-sectional view of the device 250 and the light-emitting device 260.

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

[0111] The light-emitting device 250 extracts light from the substrate 200 side (the side indicated by the arrow in Figure 4(A)). It is a light-emitting device with a so-called bottom-emission structure.

[0112] Furthermore, the light-emitting device 250 has anodes 201a separated in an island-like manner on the substrate 200. It has 201b and 201c. The substrate 200 is made of the same material as the substrate 100 shown in Embodiment 1. The anodes 201a, 201b, and 201c are the anodes shown in Embodiment 1. The materials shown in 101 can be used. Also, the anodes 201a, 201b, and 201c are... The elements emitting different colors may be provided with different thicknesses. Therefore, since it is a light-emitting device with a bottom emission structure, anodes 201a, 201b, 20 1c is formed using a material that is translucent in visible light (e.g., ITO). good.

[0113] Furthermore, the light-emitting device 250 has partitions 251a, 251b, 251c, and 251d. Wall 251a covers one end of anode 201a. Also, partition wall 251b covers anode 201a The other end of the partition wall 251c covers one end of the anode 201b. The other end of b and one end of anode 201c are covered. The partition wall 251d also covers anode 20 It covers the other end of 1c. The partitions 251a, 251b, 251c, and 251d are made of organic resin. Alternatively, inorganic insulating materials can be used. Examples of organic resins include polyimide resin. Polyamide resin, acrylic resin, siloxane resin, epoxy resin, or phenolic resin These can be used. As inorganic insulating materials, silicon oxide, silicon oxide nitride, etc. It can be used. This facilitates the fabrication of partitions 251a, 251b, 251c, and 251d. Therefore, it is particularly preferable to use a photosensitive resin.

[0114] Furthermore, the light-emitting device 250 includes anodes 201a, 201b, 201c and partition walls 251a, 25 A hole injection layer 211 is provided on 1b, 251c, and 251d. The hole injection layer 211 is provided in the implementation The material shown in the hole injection layer 111 in Embodiment 1 can be used.

[0115] Furthermore, the light-emitting device 250 has first positive holes separated in island-like shapes on the hole injection layer 211 It has a pore transport layer 213a, a second hole transport layer 213b, and a third hole transport layer 213c. Furthermore, the first hole transport layer 213a, the second hole transport layer 213b, and the third hole transport layer On 213c are, respectively, a first light-emitting layer 215a, a second light-emitting layer 215b, and a third light-emitting layer It has a layer 215c. First hole transport layer 213a, second hole transport layer 213b, third hole Pore ​​transport layer 213c, first light-emitting layer 215a, second light-emitting layer 215b, and third light-emitting layer 2 15c is the first hole transport layer 113a and the second hole transport layer 1 shown in Embodiment 1, respectively. 13b, third hole transport layer 113c, first light-emitting layer 115a, second light-emitting layer 115b, and The material shown in the third light-emitting layer 115c can be used.

[0116] Furthermore, the first light-emitting layer 215a is similar to the first light-emitting layer 115a shown in Figure 1(A), It comprises a phosphorescent material, a first electron-transporting material, and a first hole-transporting material. The second light-emitting layer 215b is similar to the second light-emitting layer 115b shown in Figure 1(A), and the second phosphorus It comprises a photosensitive material, a second electron-transporting material, and a second hole-transporting material. The light-emitting layer 215c is made of a fluorescent material, similar to the third light-emitting layer 115c shown in Figure 1(A). It comprises a third electron-transporting material. However, in Figure 4(A), to avoid the complexity of the figure, Therefore, a first phosphorescent material, a first electron transport material, a first hole transport material, a second phosphorescent material Materials, second electron-transporting materials, second hole-transporting materials, fluorescent materials, and third electron-transporting materials The materials are omitted from the illustration.

[0117] Furthermore, the light-emitting device 250 includes a first light-emitting layer 215a, a second light-emitting layer 215b, and a third An electron transport layer 217 is provided on the light-emitting layer 215c. Furthermore, an electron transport layer 217 is provided on the electron transport layer 217. It has an electron injection layer 219. Furthermore, it has a cathode 203 on the electron injection layer 219. Electron transport layer 2 17 can be the material shown in the electron transport layer 117 of Embodiment 1. The inlet layer 219 can be made of the same material as the electron injection layer 119 shown in Embodiment 1. The cathode 203 can be made of the same material as the cathode 103 shown in Embodiment 1. In the light-emitting device 250, since it is a light-emitting device with a bottom emission structure, the cathode 203 It is preferable to form it using a material that is particularly reflective (for example, aluminum).

[0118] Figure 4(A) describes a configuration in which the anode is positioned at the bottom and the cathode is positioned at the top. However, it is not limited to this, for example, a configuration in which the anode is placed at the top and the cathode is placed at the bottom. This is also acceptable. In this case, the hole injection layer, hole transport layer, light emission layer, electron injection layer, and between the anode and cathode are also included. The stacking order of the electron transport layers can be changed.

[0119] The first light-emitting layer 215a, the second light-emitting layer 215b, and the third light-emitting layer 2 of the light-emitting device 250 15c is provided in contact with the electron transport layer 217 and is a material forming the electron transport layer 217. The triplet excitation energy level of the electron transport material contained in the first light-emitting layer 215a and The triplet excitation energy level of the second electron transport material contained in the second light-emitting layer 215b is higher than the triplet excitation energy level of the second electron transport material. Low. Thus, each light-emitting element of the light-emitting device 250 has a common electron transport layer in each light-emitting layer. Even when used, the optimal element configuration results in low drive voltage and high current efficiency. or a long lifespan. Therefore, to provide a light-emitting device 250 with low power consumption or a long lifespan. It is possible to achieve this. Furthermore, because a common electron transport layer is used, it is a highly productive light-emitting device. We can provide 250.

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

[0121] The light-emitting device 260 is a modified version of the light-emitting device 250, and emits light from the side indicated by the arrow in Figure 4(B). It is a light-emitting device with a so-called top-emission structure that can be removed.

[0122] Furthermore, the light-emitting device 260 has island-shaped reflective electrodes 253 on the substrate 200. It has a, 253b, and 253c. Also, on the reflective electrodes 253a, 253b, and 253c, Each has island-like anodes 201a, 201b, and 201c. Light-emitting device 260 In this case, since it is a light-emitting device with a top emission structure, the reflective electrodes 253a, 253 b, 253c is shaped using a reflective material (e.g., aluminum or silver). It would be good to do so.

[0123] Furthermore, the light-emitting device 260 has partitions 251a, 251b, 251c, and 251d. Wall 251a covers one end of the reflecting electrode 253a and the anode 201a. Also, partition wall 25 1b is the other end of the reflective electrode 253a and anode 201a, and the reflective electrode 253b and anode It covers one end of 201b. The partition wall 251c also covers the reflecting electrode 253b and the anode 201 It covers the other end of b and one end of the reflector electrode 253c and anode 201c. Also, partition wall 251d covers the reflective electrode 253c and the other end of the anode 201c.

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

[0125] Furthermore, the light-emitting device 260 has first positive holes separated in island-like shapes on the hole injection layer 211 It has a pore transport layer 213a, a second hole transport layer 213b, and a third hole transport layer 213c. Furthermore, the first hole transport layer 213a, the second hole transport layer 213b, and the third hole transport layer On 213c are, respectively, a first light-emitting layer 215a, a second light-emitting layer 215b, and a third light-emitting layer It has layer 215c.

[0126] Furthermore, the first light-emitting layer 215a is similar to the first light-emitting layer 115a shown in Figure 1(A), It comprises a phosphorescent material, a first electron-transporting material, and a first hole-transporting material. The second light-emitting layer 215b is similar to the second light-emitting layer 115b shown in Figure 1(A), and the second phosphorus It comprises a photosensitive material, a second electron-transporting material, and a second hole-transporting material. The light-emitting layer 215c is made of a fluorescent material, similar to the third light-emitting layer 115c shown in Figure 1(A). It has a third electron-transporting material. However, in Figure 4(B), to avoid the complexity of the figure, Therefore, a first phosphorescent material, a first electron transport material, a first hole transport material, a second phosphorescent material Material, second electron transport material, second hole transport material, fluorescent material, third electron transport material The details are omitted in the illustration.

[0127] Furthermore, the light-emitting device 260 includes a first light-emitting layer 215a, a second light-emitting layer 215b, and a third An electron transport layer 217 is provided on the light-emitting layer 215c. Furthermore, an electron transport layer 217 is provided on the electron transport layer 217. It has an electron injection layer 219. Furthermore, on the electron injection layer 219, there is a semi-transmissive and semi-reflective layer that functions as a cathode. It has an electrode 253. The semi-transmissive / semi-reflective electrode 253 is, for example, a thin metal film (preferably 2 A conductive metal oxide is formed by laminating a material (0 nm or less, more preferably 10 nm or less). This can be done. As a thin metal film, silver, magnesium, or a compound containing these metallic materials can be used. Gold and the like can be formed in a single layer or in layers. As for conductive metal oxides, oxidation Indium (In2O3), tin oxide (SnO2), zinc oxide (ZnO), ITO, oxide Indium zinc oxide (In2O3-ZnO), or these metal oxide materials with silicate oxide Products containing corn 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 The resonance effect of light is utilized between 253a, 253b, 253c and the semi-transmissive / semi-reflective electrode 253. By employing a micro-optical resonator (microcavity), the light intensity at a specific wavelength is increased. This can be done. Furthermore, this function as a microcavity is achieved by the reflective electrode 253a. The material sandwiched between 253b, 253c and the semi-transmissive / semi-reflective electrode 253, or the optical path length, etc. It is possible to adjust this. For example, anodes 201a, 201b, 201c, and the first hole The film thickness of the transport layer 213a, the second hole transport layer 213b, and the third hole transport layer 213c was adjusted. By adjusting the light emission, the intensity of light of a specific wavelength emitted from each light-emitting layer can be increased. In the configuration 260, there is a first hole transport layer 213a, a second hole transport layer 213b, and a third This example illustrates a configuration in which the optical path length is adjusted by the thickness of the hole transport layer 213c.

[0129] Furthermore, Figure 4(B) describes a configuration in which the anode is placed at the bottom and the cathode is placed at the top. However, it is not limited to this, for example, a configuration in which the anode is placed at the top and the cathode is placed at the bottom. This is also acceptable. In this case, the hole injection layer, hole transport layer, light emission layer, electron injection layer, and between the anode and cathode are also included. The stacking order of the electron transport layers can be changed.

[0130] The first light-emitting layer 215a, the second light-emitting layer 215b, and the third light-emitting layer 2 of the light-emitting device 260 15c is provided in contact with the electron transport layer 217 and is a material forming the electron transport layer 217. The triplet excitation energy level of the electron transport material contained in the first light-emitting layer 215a and The triplet excitation energy level of the second electron transport material contained in the second light-emitting layer 215b is higher than the triplet excitation energy level of the second electron transport material. Low. Thus, each light-emitting element of the light-emitting device 260 has a common electron transport layer in each light-emitting layer. Even when used, the optimal element configuration results in low drive voltage and high current efficiency. or a long lifespan. Therefore, to provide a light-emitting device 260 with low power consumption or a long lifespan. It is possible to achieve this. Furthermore, because a common electron transport layer is used, it is a highly productive light-emitting device. We can provide 260.

[0131] Furthermore, the light-emitting device 250 shown in Figure 4(A) and the light-emitting device 260 shown in Figure 4(B) are on a substrate Although an example was given of a configuration in which only light-emitting elements are formed on 200, the example is not limited to this, for example If a transistor (for example, a TFT) is formed separately on the substrate 200, the transistor And, anodes 201a, 201b, 201c or reflector electrodes 253a, 253b, 253c It is preferable to configure the system to electrically connect the components.

[0132] Here, we will explain the method for manufacturing the light-emitting device 250 shown in Figure 4(A).

[0133] First, a conductive film is formed on the substrate 200, and the conductive film is processed into a desired shape to form an anode 2 Form 01a, 201b, and 201c. Next, form the substrate 200 and anodes 201a, 201b , partition walls 251a, 251b, 251c, and 251d are formed on 201c. Note that anode 2 01a, 201b, 201c and bulkheads 251a, 251b, 251c, 251d are tra It is preferable to form it during the manufacturing process of the radiator.

[0134] Furthermore, the structure of the above transistor is not limited, and a top-gate type transistor can be used. Alternatively, bottom-gate transistors such as inverse staggered transistors may be used. Either a channel-type transistor or a p-channel-type transistor may be used. The materials used for the transistor are not particularly limited. For example, silicon or In-Ga- This application involves transistors that use oxide semiconductors such as Zn-based metal oxides in the channel formation region. It is possible.

[0135] Next, anodes 201a, 201b, 201c and partitions 251a, 251b, 251c, 2 A hole injection layer 211 is formed on 51d. The anodes 201a, 201b, and 201c are deposited Using methods (including vacuum deposition), sputtering, coating, or inkjet It can be formed. In addition, the hole injection layer 211 can be formed by evaporation (including vacuum evaporation) and transfer. It can be formed by methods such as printing, inkjet printing, coating, etc.

[0136] Next, the first hole transport layer 21 is positioned in contact with the hole injection layer 211 and overlapping with the anode 201a. 3a is formed. The first hole transport layer 213a is formed by deposition (including vacuum deposition), transfer, It can be formed by methods such as printing, inkjet, and coating. In this case, a vapor deposition method is used, and a vapor deposition mask (metal mask, fine metal mask, or shading mask) is used. It is formed in the desired region using a dome mask.

[0137] Next, a first light-emitting layer 215a is formed on the first hole transport layer 213a. 215a refers to vapor deposition methods (including vacuum deposition), transfer methods, printing methods, inkjet methods, and coating methods. It can be formed by methods such as those described above. In this embodiment, a vapor deposition method is used to form a vapor deposition mask. Using a metal mask (also called a fine metal mask or shadow mask), It is formed in the region. Note that the first hole transport layer 213a and the first light-emitting layer 215a are the same It is preferable to form them continuously using a vapor deposition mask.

[0138] Next, a second hole transport layer 21 is placed in contact with the hole injection layer 211 and superimposed on the anode 201b. 3b is formed. The second hole transport layer 213b is formed using the same method as the first hole transport layer 213a. It can be formed using [this method].

[0139] Next, a second light-emitting layer 215b is formed on the second hole transport layer 213b. Layer 215b can be formed using the same method as the first light-emitting layer 215a. The second hole transport layer 213b and the second light-emitting layer 215b are deposited using the same deposition mask. It is preferable to form them in succession.

[0140] Next, a third hole transport layer 21 is placed in contact with the hole injection layer 211 and superimposed on the anode 201c. 3c is formed. The third hole transport layer 213c is formed using the same method as the first hole transport layer 213a. It can be formed using [this method].

[0141] Next, a third light-emitting layer 215c is formed on the third hole transport layer 213c. Layer 215c can be formed using the same method as the first light-emitting layer 215a. The third hole transport layer 213c and the third light-emitting layer 215c are deposited using the same deposition mask. It is preferable to form them in succession.

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

[0143] Next, a cathode 203 is formed on the electron injection layer 219. The cathode 203 is formed by a vapor deposition method (vacuum deposition). Formed using methods including sputtering, coating, or inkjet. It is possible.

[0144] Based on the above, the light-emitting device 250 shown in Figure 4(A) can be manufactured.

[0145] Furthermore, the light-emitting device 260 shown in Figure 4(B) is manufactured using the same process as the light-emitting device 250, plus a light-emitting device. Reflective electrodes 253a, 253b, and 253c are formed below electrodes 201a, 201b, and 201c. The process involves adding the steps of forming a semi-transparent / semi-reflective electrode 253 instead of the cathode 203. It can be formed by doing so.

[0146] The configuration shown in this embodiment may be combined with the configurations shown in other embodiments or examples as appropriate. They can be combined.

[0147] (Embodiment 4) In this embodiment, various light-emitting devices or light-emitting devices completed using one aspect of the present invention are shown. An example of electronic equipment and lighting devices will be explained using Figure 5.

[0148] Examples of electronic devices include television equipment (televisions, or television receivers) (Also known as), computer monitors, digital cameras, digital video cameras, digital Photo frames, mobile phones (also called mobile phones or mobile phone devices), portable game consoles Examples include personal digital assistants, audio playback devices, and large game machines such as pachinko machines.

[0149] A light-emitting element according to one aspect of the present invention is fabricated on a flexible substrate, thereby having a curved surface. This enables the realization of electronic devices and lighting devices that have light-emitting parts.

[0150] Furthermore, the pair of electrodes provided in one embodiment of the present invention have light transmission to visible light By forming it using materials, electronic devices and lighting devices with see-through light-emitting parts can be realized. It is possible.

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

[0152] Figure 5(A) shows an example of a television system. The television system 7100 is, The display unit 7103 is integrated into the housing 7101. The display unit 7103 displays video. It is possible to do so, and the light-emitting device can be used in the display unit 7103. This shows a configuration in which the housing 7101 is supported by the stand 7105.

[0153] The television unit 7100 is operated using the control switches on the housing 7101, or a separate unit. This can be done using the remote control unit 7110. The remote control unit 7110 has an operating key - 7109 allows you to control the channel and volume, and the information is displayed on the display unit 7103. The video can be controlled. Furthermore, the remote control unit 7110 can control the remote control. A display unit 7107 may also be provided to display information output from the unit 7110.

[0154] The television system 7100 will consist of a receiver, modem, and other components. This allows you to receive regular television broadcasts, and furthermore, via a modem, you can connect via wired or wireless connection. By connecting to a communication network, one-way (sender to receiver) or two-way ( It is also possible to communicate information between a sender and a receiver, or between receivers themselves.

[0155] Figure 5(B) is a computer, consisting of the main unit 7201, the casing 7202, the display unit 7203, and a key - Includes board 7204, external connection port 7205, pointing device 7206, etc. Furthermore, the computer is manufactured by using a light-emitting device in its display unit 7203. .

[0156] Figure 5(C) shows a portable gaming machine, which consists of two cabinets, cabinet 7301 and cabinet 7302. It is connected by a connecting part 7303 so that it can be opened and closed. The housing 7301 has a display unit The 7304 is incorporated, and the display unit 7305 is incorporated into the housing 7302. The portable gaming machine shown in 5(C) also includes a speaker unit 7306 and a recording medium insertion unit 7307. LED lamp 7308, input means (operation key 7309, connection terminal 7310, sensor 73 11 (Force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical Chemical substances, sound, time, hardness, electric field, electric current, voltage, power, radiation, flow rate, humidity, gradient, vibration Equipped with a function to measure odor or infrared radiation, a microphone (7312), etc. Of course, the configuration of a portable gaming machine is not limited to those described above, and at least the display unit 73 It is sufficient to use a light-emitting device in both or one of 04 and the display unit 7305, and other accessories The equipment can be configured as appropriate. The portable gaming machine shown in Figure 5(C) is a record Functions that read programs or data recorded on a medium and display them on the display unit, and other It has the function of sharing information by communicating wirelessly with portable gaming machines. (See Figure 5(C)) The functions of a portable gaming machine are not limited to these, and it can have a variety of functions.

[0157] Figure 5(D) shows an example of a mobile phone. Mobile phone 7400 has a housing 7401 In addition to the display unit 7402 incorporated into it, there are operation buttons 7403, an external connection port 7404, and It is equipped with a speaker 7405, a microphone 7406, etc. Note that the mobile phone 7400 has a light source. The device is manufactured by using it in the display unit 7402.

[0158] The mobile phone 7400 shown in Figure 5(D) allows information to be conveyed by touching the display unit 7402 with a finger or the like. You can enter information. You can also perform operations such as making phone calls or composing emails. This can be done by touching the display unit 7402 with a finger or the like.

[0159] The display unit 7402 has three main modes. The first is primarily for displaying images. The first is the display mode, the second is the input mode which is mainly for inputting information such as characters. The third is the display mode. This is a display + input mode, which is a combination of two modes: display mode and input mode.

[0160] For example, when making a phone call or composing an email, the display unit 7402 is used for text input. The primary text input mode is set to [this mode], and you should perform the input operation for the characters displayed on the screen. In addition, it is preferable to display a keyboard or number buttons on most of the screen of the display unit 7402. It seems so.

[0161] Furthermore, the 7400 mobile phone contains sensors that detect tilt, such as a gyroscope and an accelerometer. By providing a detection device having the following, the orientation (vertical or horizontal) of the mobile phone 7400 can be determined, The display on the display unit 7402 can be configured to switch screen displays automatically.

[0162] Furthermore, the screen mode can be switched by touching the display unit 7402 or by operating the housing 7401. This is done by operating the action button 7403. Also, the type of image displayed on the display unit 7402 It can also be configured to switch between modes. For example, if the image signal displayed on the display unit is a video If the data is in a specific format, it switches to display mode; if it's text data, it switches to input mode.

[0163] Furthermore, in input mode, the signal detected by the optical sensor of the display unit 7402 is detected, and the display If there is no input via touch operation on the display unit 7402 for a certain period of time, the screen mode will be changed to input mode. You may also control the system to switch from the "Do" display mode to the "Display Mode".

[0164] The display unit 7402 can also function as an image sensor. For example, the display unit 7 By touching device 402 with the palm or fingers, the user can be authenticated by capturing images of their palm print, fingerprints, etc. Furthermore, the display unit may have a backlight that emits near-infrared light or a sensing light that emits near-infrared light. Using the appropriate source, it is also possible to image finger veins, palmar veins, and other veins.

[0165] Figure 5(E) shows a tabletop lighting device, consisting of a lighting unit 7501, a shade 7502, and a variable arm 7503. This includes the support column 7504, the base 7505, and the power supply 7506. Note that the table lighting device includes the light-emitting device. It is manufactured by using it in the lighting unit 7501. The lighting device includes ceiling-mounted lighting fixtures. This also includes fixtures or wall-mounted lighting fixtures.

[0166] The configuration shown in this embodiment may be combined with the configurations shown in other embodiments or examples as appropriate. They can be combined. [Examples]

[0167] In this embodiment, 9- can be used as an electron transport layer for a light-emitting element according to one aspect of the present invention. [4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation) :CzPA) and the host material of the phosphorescent element (first electron transport material and second electron transport material 2-[3'-(dibenzothiophen-4-yl)bife (which can be used as a material) [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 determined by measuring the phosphorescence emission of each substance. The measurement conditions were as follows: The measurements were taken by irradiating each substance with excitation light at 325 nm and at a measurement temperature of 10 K. For TBPDBq-II, time-resolved measurements were performed using a mechanical chopper. Regarding PA, since time-resolved measurement is difficult, Ir(ppy)3 is added as a sensitizer. Measurements were performed without time resolution. The measurement conditions were as follows: CzPA was 3 times the weight ratio. Ir(ppy)3 was added at a ratio of 1. Note that the triplet excitation energy level was measured by Calculating from the absorption wavelength is more accurate than calculating from the light wavelength. However, the absorption at the T1 level is extremely difficult. Because the emission is very weak and difficult to measure, here we measure the emission wavelength to determine the T One level was determined. Therefore, the measured values ​​should be expected to contain some error. The measurement results are shown in Table 1. As shown.

[0170] [Table 1]

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

[0172] In this embodiment, a light-emitting element (light-emitting element 1, light-emitting element 3, and light-emitting element 5) according to one aspect of the present invention is shown. ), and comparative light-emitting elements (comparative light-emitting element 2, comparative light-emitting element 4, and comparative light-emitting element 6) This will be explained using Figure 6(A). The chemical formulas of the materials used in this embodiment are shown below. vinegar.

[0173] [ka]

[0174] [ka]

[0175] Below are the light-emitting elements (light-emitting element 1, light-emitting element 3, and) of one embodiment of the present invention used in this embodiment. Light-emitting element 5), and comparative light-emitting elements (comparative light-emitting element 2, comparative light-emitting element 4, and comparative light-emitting element 4). The method for fabricating element 6) is shown below.

[0176] Note that light-emitting element 1 and comparative light-emitting element 2 are light-emitting elements that emit red light. 3 and comparative light-emitting element 4 are light-emitting elements that emit green light, and light-emitting element 5 and comparative light-emitting element Child 6 is a light-emitting element that emits blue light.

[0177] (light-emitting element 1) First, on the substrate 1100, indium oxide-tin oxide containing silicon or silicon oxide The compound (ITO-SiO2, hereinafter abbreviated as ITSO) was deposited as a film by sputtering. Then, anode 1101 was formed. The composition of the target used was In2O3:SnO2: The SiO2 ratio was set to 85:10:5 [weight%]. The film thickness of anode 1101 was 110 nm. The electrode area was set to 2 mm x 2 mm.

[0178] Next, as a pretreatment for forming light-emitting elements on the substrate 1100, the substrate surface is washed with water. Then, after baking at 200°C for 1 hour, UV ozone treatment was performed for 370 seconds.

[0179] Then, 10 -4 A substrate is introduced into a vacuum deposition apparatus where the internal pressure is reduced to approximately Pa, and then vacuum vapor After vacuum firing at 170°C for 30 minutes in the heating chamber of the mounting device, the substrate 1100 It was left to cool for about 30 minutes.

[0180] Next, the base on which the anode 1101 is formed is positioned so that the surface on which the anode 1101 is formed faces downwards. The plate 1100 is fixed to a substrate holder provided inside the vacuum deposition apparatus, 10 -4 Up to approximately Pa After reducing the pressure, 4,4',4''-( Benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-I) I) A hole injection layer 1111 was formed by co-depositing molybdenum oxide with [the other material]. The film thickness was 4 Assuming 0 nm, the ratio of DBT3P-II to molybdenum oxide is 4:2 by weight (=DBT3 The mixture was adjusted to be P-II (molybdenum oxide). Note that the co-evaporation method is a single processing chamber. This is a vapor deposition method in which deposition is carried out simultaneously from multiple evaporation sources within a structure.

[0181] Next, on the hole injection layer 1111, 4-phenyl-4'-(9-phenylfluorene-9 - A film of triphenylamine (BPAFLP) is deposited to a thickness of 20 nm. This formed a hole transport layer 1113.

[0182] Next, 2mDBTBPDBq-II and 4,4'-di(1-naphthyl)-4''-(9 -phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBNBB) ) and (dipivaloylmethanato)bis(2,3,5-triphenylpyradinato)iridium Mu(III) (abbreviation: Ir(tppr)2dpm) and are co-deposited, and hole transport layer 1113 A light-emitting layer 1115 was formed on top. Here, 2mDBTBPDBq-II, PCBNBB, The weight ratio of Ir(tppr)2dpm is 0.8:0.2:0.06 (=2mDBTB). The settings were adjusted so that PDBq-II:PCBNBB:Ir(tppr)2dpm). Furthermore, the film thickness of the light-emitting layer 1115 was set to 40 nm.

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

[0184] Furthermore, CzPA is deposited on the light-emitting layer 1115 to a thickness of 10 nm, and the electron transport layer Formed 1117.

[0185] Subsequently, bathophenanthroline (abbreviated as BPhen) is applied to the electron transport layer 1117 at a film thickness of 1 A film was deposited to a thickness of 5 nm to form the first electron injection layer 1119a.

[0186] Furthermore, lithium fluoride (LiF) is applied to the first electron injection layer 1119a to a thickness of 1 nm. A second electron injection layer 1119b was formed by deposition.

[0187] Finally, aluminum is used as the cathode 1103 on the second electron injection layer 1119b, with a value of 200 The light-emitting element 1 of this embodiment was fabricated by depositing a film thickness of nm.

[0188] (Comparison light-emitting element 2) The comparative light-emitting element 2 differs from the light-emitting element 1 in its electron transport layer 1117. Specifically, The electron transport layer 1117 of the light-emitting element 2 uses 2mD instead of the CzPA used in the light-emitting element 1. BTBPDBq-II was used. The film thickness of 2mDBTBPDBq-II was 10 nm. did.

[0189] Furthermore, the configuration of the comparative light-emitting element 2 is the same as that of the light-emitting element 1, except for the electron transport layer 1117. It was made in this way.

[0190] (light-emitting element 3) The light-emitting element 3 differs from the light-emitting element 1 in its light-emitting layer 1115. Specifically, the light-emitting element 3 The light-emitting layer 1115 is made of 2mDBTBPDBq-II, PCBNBB, used in the light-emitting element 1. And instead of Ir(tppr)2dpm, use 2mDBTBPDBq-II, PCBNBB , and (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato Iridium(III) (abbreviation: Ir(tBuppm)2(acac)) was used.

[0191] Furthermore, the light-emitting layer 1115 of the light-emitting element 3 is made of 2mDBTBPDBq-II and PCBNBB It was formed by co-depositing Ir(tBuppm)2(acac) and 2mDBT. The weight ratios of BPDBq-II, PCBNBB, and Ir(tBuppm)2(acac) are , 0.8:0.2:0.06(=2mDBTBPDBq-II:PCBNBB:Ir(t The settings were adjusted so that Buppm)2(acac)). Also, the light-emitting layer 111 of the light-emitting element 3 The film thickness of 5 was set to 40 nm.

[0192] Furthermore, in the light-emitting layer 1115 of the light-emitting element 3, 2mDBTBPDBq-II is an electron transport It is a hole-transporting material and functions as a host material. Furthermore, PCBNBB is a hole-transporting material. It exists and functions as an assisting material. Also, Ir(tBuppm)2(acac) is It is an organometallic complex containing lysium and functions as a guest material.

[0193] Furthermore, the light-emitting element 3 is manufactured in the same way as the light-emitting element 1, except for the light-emitting layer 1115. did.

[0194] (Comparison light source 4) The comparative light-emitting element 4 differs from the light-emitting element 1 in its light-emitting layer 1115 and electron transport layer 1117. Specifically, the light-emitting layer 1115 of the comparative light-emitting element 4 is 2 mDBTB, the same as that used in the light-emitting element 1. Instead of PDBq-II, PCBNBB, and Ir(tppr)2dpm, use 2mDBT. BPDBq-II, PCBNBB, and Ir(tBuppm)2(acac) were used. Furthermore, the electron transport layer 1117 of the comparative light-emitting element 4 is used instead of the CzPA used in the light-emitting element 1. 2mDBTBPDBq-II was used.

[0195] Furthermore, the light-emitting layer 1115 of the comparative light-emitting element 4 is made of 2mDBTBPDBq-II and PCBN BB and Ir(tBuppm)2(acac) were co-deposited to form the structure. Here, 2mD Weights of BTBPDBq-II, PCBNBB, and Ir(tBuppm)2(acac) The ratio is 0.8:0.2:0.06 (=2mDBTBPDBq-II:PCBNBB:Ir The settings were adjusted to (tBuppm)2(acac). Also, the light emission of the comparison light-emitting element 4 was adjusted. The film thickness of layer 1115 was set to 40 nm.

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

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

[0198] (Light-emitting element 5) The light-emitting element 5 differs from the light-emitting element 1 in its light-emitting layer 1115. Specifically, the light-emitting element 5 The light-emitting layer 1115 is made of 2mDBTBPDBq-II, PCBNBB, used in the light-emitting element 1. And instead of Ir(tppr)2dpm, CzPA and N,N'-bis(3-methyl Phenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl] [Nyl]-pyrene-1,6-diamine (abbreviated as 1,6mMemFLPAPrn) was used.

[0199] Furthermore, the light-emitting layer 1115 of the light-emitting element 5 is made of CzPA and 1,6mMemFLPAPrn , were co-deposited and formed. Here, the weight ratio of CzPA and 1,6mMemFLPAPrn This was adjusted to 1:0.05 (=CzPA:1,6mMemFLPAPrn). Furthermore, the film thickness of the light-emitting layer 1115 of the light-emitting element 5 was set to 25 nm.

[0200] Furthermore, in the light-emitting layer 1115 of the light-emitting element 5, CzPA is an electron transport material, It functions as a fluorescent material. Furthermore, 1,6mMemFLPAPrn is a fluorescent material. It functions as a guest ingredient.

[0201] Furthermore, the light-emitting element 5 is manufactured in the same manner as the light-emitting element 1, except for the light-emitting layer 1115. did.

[0202] (Comparison light-emitting element 6) The comparative light-emitting element 6 differs from the light-emitting element 1 in its light-emitting layer 1115 and electron transport layer 1117. Specifically, the light-emitting layer 1115 of the comparative light-emitting element 6 is 2 mDBTB, the same as that used in the light-emitting element 1. Instead of PDBq-II, PCBNBB, and Ir(tppr)2dpm, use CzPA. And 1,6mMemFLPAPrn was used. Also, the electron transport layer 111 of the comparative light-emitting element 6 In version 7, 2mDBTBPDBq-II was used instead of CzPA, which was used in light-emitting element 1.

[0203] Furthermore, the light-emitting layer 1115 of the comparative light-emitting element 6 is made of CzPA and 1,6mMemFLPAPr n and were co-deposited to form the structure. Here, the weight of CzPA and 1,6mMemFLPAPrn The ratio should be adjusted to 1:0.05 (=CzPA:1,6mMemFLPAPrn). Furthermore, the film thickness of the light-emitting layer 1115 of the comparative light-emitting element 6 was set to 25 nm.

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

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

[0206] Note that the comparative light-emitting element 6 has a configuration other than the light-emitting layer 1115 and the electron transport layer 1117. It was fabricated in the same manner as light-emitting element 1.

[0207] Furthermore, the light-emitting elements (light-emitting element 1, light-emitting element 3, and light-emitting element 5) according to one embodiment of the present invention described above. ), and vaporization of the comparative light-emitting elements (comparative light-emitting element 2, comparative light-emitting element 4, and comparative light-emitting element 6) The entire process involved resistance heating.

[0208] Thus, a light-emitting element (light-emitting element 1, light-emitting element 3, and light-emitting element 5) according to one aspect of the present invention And the comparison light-emitting elements (comparative light-emitting element 2, comparative light-emitting element 4, and comparative light-emitting element 6) emit light. The configuration is the same except for layer 1115 and electron transport layer 1117.

[0209] The light-emitting element (light-emitting element 1, light-emitting element 3, and light-emitting element) obtained as described above in one embodiment of the present invention Child 5), and the comparison light-emitting elements (comparison light-emitting elements 2, 4, and 6) The device structure is shown in Table 2.

[0210] [Table 2]

[0211] As shown in Table 2, one embodiment of the present invention is a light-emitting element made of phosphorescent material (light-emitting element 1 and light-emitting element 1). 3) As the host material, 2mDBTBPDBq-II is used, and a fluorescent material (light-emitting element 5 CzPA is used as the host material for ). In addition, light-emitting element 1, light-emitting element 3, and The electron transport layer of optical element 5 uses a common CzPA. On the other hand, the light-emitting element for comparison uses As the host material for the phosphorescent material (comparative light-emitting element 2 and comparative light-emitting element 4), 2mDBTBP Using DBq-II, CzPA was used as the host material for the fluorescent material (comparative light-emitting element 6). Furthermore, the electron transport layers of comparative light-emitting element 2, comparative light-emitting element 4, and comparative light-emitting element 6 are They use the common 2mDBTBPDBq-II.

[0212] Next, each of the light-emitting elements prepared above is exposed to the atmosphere inside a glove box with a nitrogen atmosphere. To prevent this, the device is sealed with a glass substrate (a sealing material is applied around the element, and when sealed...) The device was then heat-treated at 80°C for 1 hour. After that, the operating characteristics of each light-emitting element were measured. The measurements were taken at room temperature (in an atmosphere maintained at 25°C).

[0213] Figure 7 shows the current density-luminance characteristics of light-emitting element 1 and comparative light-emitting element 2, and Figure 8 shows the voltage-luminance characteristics. Figure 9 shows the luminance-current efficiency characteristics, Figure 10 shows the voltage-current characteristics, and Figure 11 shows the emission spectrum. These are shown below.

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

[0215] Figure 17 shows the current density-luminance characteristics of light-emitting element 5 and comparative light-emitting element 6, and the voltage-luminance characteristics. Figure 18 shows the luminance-current efficiency characteristics, Figure 19 shows the voltage-current characteristics, and Figure 20 shows the emission spectrum. These are shown in Figure 21.

[0216] In Figures 7, 12, and 17, the horizontal axis represents current density (mA / cm²). 2 ) on the vertical axis luminance (cd / m²) 2 ) represents. Also, in Figures 8, 13, and 18, the horizontal axis represents voltage ( The vertical axis represents luminance (cd / m²), with V) being the vertical axis representing luminance (cd / m²). 2 ) represents. Also, in Figures 9, 14, and 19, The horizontal axis represents luminance (cd / m²). 2 The vertical axis represents current efficiency (cd / A). See also Figures 10 and 15. In Figure 11, the horizontal axis represents voltage (V) and the vertical axis represents current (mA). In Figures 16 and 21, the horizontal axis represents wavelength (nm), and the vertical axis represents intensity (in arbitrary units). Note that in Figures 11, 16, and 21, the emission spectra of each light-emitting element roughly overlap. It is.

[0217] Furthermore, the brightness of each light-emitting element is 1000 cd / m². 2 Voltage (V) and current density at the vicinity (mA / cm 2 ), CIE chromaticity coordinates (x, y), current efficiency (cd / A), external quantum efficiency ( The percentages are shown in Table 3.

[0218] [Table 3]

[0219] As shown in Table 3, the brightness of the light-emitting element 1 is 992 cd / m². 2 As for the element characteristics in this case, current effect The chromaticity is 27 cd / A, the external quantum efficiency is 24%, and the CIE chromaticity coordinates are (x,y) The values ​​were (0.66, 0.34). Also, the brightness of the comparison light-emitting element 2 was 1103 cd / m².2 oh The element characteristics are as follows: current efficiency is 27 cd / A, external quantum efficiency is 23%, and C The IE chromaticity coordinates were (x,y)=(0.66,0.34).

[0220] Furthermore, as shown in Figure 11, the emission spectra of light-emitting element 1 and comparative light-emitting element 2 are 619 It has a peak at nm.

[0221] As described above, when comparing light-emitting element 1 and comparative light-emitting element 2, no significant differences in element characteristics were observed. It is not done. That is, the electron transport properties of the electron transport layer 1117 (CzPA) of the light-emitting element 1, and The electron transport of the electron transport material (2mDBTBPDBq-II), which is the host material for phosphorescent materials. Because of its extremely high transportability, the light emitted in the light-emitting layer 1115 diffuses towards the electron transport layer 1117. It was confirmed that the element configuration does not cause diffusion, or is less prone to diffusion.

[0222] Furthermore, as shown in Table 3, the brightness of the light-emitting element 3 is 804 cd / m². 2 As for the element characteristics in, The current efficiency is 91 cd / A, the external quantum efficiency is 26%, and the CIE chromaticity coordinate is (x The values ​​were (y) = (0.43, 0.56). Also, the brightness of the comparison light-emitting element 4 was 987 cd / m². 2 The device characteristics are as follows: current efficiency is 93 cd / A, and external quantum efficiency is 26%. The CIE chromaticity coordinates were (x,y)=(0.43,0.56).

[0223] Furthermore, as shown in Figure 16, the emission spectra of the light-emitting element 3 and the comparative light-emitting element 4 are as follows: It has peaks at 549nm and 546nm.

[0224] As described above, when comparing light-emitting element 3 and comparative light-emitting element 4, no significant differences in element characteristics were observed. It is not done. In other words, the electron transport properties of the electron transport layer 1117 (CzPA) of the light-emitting element 3 and phosphorus Electron transport of electron transport material (2mDBTBPDBq-II), which is a host material for photomaterials. Because of its extremely high properties, the light emitted in the light-emitting layer 1115 diffuses towards the electron transport layer 1117. It was confirmed that the element configuration does not contain or does not easily diffuse particles.

[0225] Furthermore, as shown in Table 3, the brightness of the light-emitting element 5 is 905 cd / m². 2 As for the element characteristics in, The current efficiency is 11 cd / A, the external quantum efficiency is 9%, and the CIE chromaticity coordinate is (x, y) = (0.14, 0.19). Also, the brightness of the comparison light-emitting element 6 was 1115 cd / m². 2 The device characteristics are as follows: current efficiency is 12 cd / A, and external quantum efficiency is 9%. The CIE chromaticity coordinates were (x,y)=(0.14,0.19).

[0226] Furthermore, as shown in Figure 21, the emission spectra of the light-emitting element 5 and the comparative light-emitting element 6 are as follows: It has peaks at 464nm and 465nm.

[0227] As described above, when comparing the light-emitting element 5 with the comparative light-emitting element 6, differences in element characteristics are observed. Specifically, as shown in Table 3 and Figure 20, the differences mainly lie in the voltage-current characteristics. The light-emitting element 5 has a capacitance of 905 cd / m². 2 The voltage at is 3.3V, and the comparison light-emitting element 6 is 1 115 cd / m² 2 The voltage at that point is 3.5V. Also, as shown in Figure 20, it is around 3V. When the voltage is increased, the current value of the comparative light-emitting element 6 is lower than that of the light-emitting element 5 in one embodiment of the present invention. .

[0228] This is because the electron transport layer 1117 of the comparative light-emitting element 6 is an electron transport layer that is a host material of a phosphorescent material. This is due to the use of transportable material (2mDBTBPDBq-II). The host material of the material is compared to the electron transport material (CzPA) used in the light-emitting layer 1115. This results in reduced electron transport efficiency.

[0229] On the other hand, the light-emitting element 5 in one aspect of the present invention has an electron transport function of the electron transport layer 1117 (CzPA) However, the electron transport material (2mDBTBPDBq-II), which is the host material for phosphorescent materials, Because it has superior transport properties, it exhibits excellent device characteristics at lower drive voltages.

[0230] Note that the configuration shown in this embodiment is not the same as the configuration shown in other embodiments or the configuration shown in other embodiments. It can be used in appropriate combination with other elements. [Examples]

[0231] In this embodiment, a light-emitting element (light-emitting element 7 and light-emitting element 8) according to one aspect of the present invention is shown in Figure We will explain using 6(B). The chemical formulas of the materials used in this example are shown below.

[0232] [ka]

[0233] [ka]

[0234] The following describes the light-emitting element (light-emitting element 7 and light-emitting element 8) according to one embodiment of the present invention used in this embodiment. The manufacturing method is shown.

[0235] Furthermore, light-emitting element 7 is a light-emitting element that emits red light, and light-emitting element 8 emits green light. This is a light-emitting element.

[0236] (light-emitting element 7) First, on the substrate 1100, indium oxide-tin oxide containing silicon or silicon oxide A compound (ITSO) was deposited by sputtering to form the anode 1101. The composition of the target was In2O3:SnO2:SiO2 = 85:10:5 [weight %] The film thickness of anode 1101 was set to 110 nm, and the electrode area was set to 2 mm × 2 mm. Ta.

[0237] Next, as a pretreatment for forming light-emitting elements on the substrate 1100, the substrate surface is washed with water. Then, after baking at 200°C for 1 hour, UV ozone treatment was performed for 370 seconds.

[0238] Then, 10 -4 A substrate is introduced into a vacuum deposition apparatus where the internal pressure is reduced to approximately Pa, and then vacuum vapor After vacuum firing at 170°C for 30 minutes in the heating chamber of the mounting device, the substrate 1100 It was left to cool for about 30 minutes.

[0239] Next, the base on which the anode 1101 is formed is positioned so that the surface on which the anode 1101 is formed faces downwards. The plate 1100 is fixed to a substrate holder provided inside the vacuum deposition apparatus, 10 -4 Up to approximately Pa After reducing the pressure, 4,4',4''-( Benzene-1,3,5-triyl)tri(dibenzothiophene)((abbreviation: DBT3P- II) A hole injection layer 1111 was formed by co-depositing molybdenum oxide with [the other material]. The film thickness was 4 Assuming 0 nm, the ratio of DBT3P-II to molybdenum oxide is 4:2 by weight (=DBT3 The formula was adjusted so that P-II (molybdenum oxide) was used.

[0240] Next, on the hole injection layer 1111, 4-phenyl-4'-(9-phenylfluorene-9 - A film of triphenylamine (BPAFLP) is deposited to a thickness of 20 nm. This formed a hole transport layer 1113.

[0241] Next, 2mDBTBPDBq-II and 4,4'-di(1-naphthyl)-4''-(9 -phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBNBB) ) and (dipivaloylmethanato)bis(2,3,5-triphenylpyradinato)iridium Mu(III) (abbreviation: Ir(tppr)2dpm) and are co-deposited, and hole transport layer 1113 A light-emitting layer 1115 was formed on top. Here, 2mDBTBPDBq-II, PCBNBB, The weight ratio of Ir(tppr)2dpm is 0.8:0.2:0.06 (=2mDBTB). The settings were adjusted so that PDBq-II:PCBNBB:Ir(tppr)2dpm). Furthermore, the film thickness of the light-emitting layer 1115 was set to 40 nm.

[0242] Furthermore, in the light-emitting layer 1115, 2mDBTBPDBq-II is an electron transport material. Furthermore, PCBNBB is a hole transport material and functions as a host material. It functions as a material. In addition, Ir(tppr)2dpm is an organometallic compound containing iridium. It is a complex and functions as a guest material.

[0243] Furthermore, CzPA and 1,6mMemFLPAPrn are co-deposited onto the light-emitting layer 1115. Then, an electron transport layer 1117a was formed on the light-emitting layer 1115. Here, CzPA and 1, The weight ratio of 6mMemFLPAPrn is 1:0.05 (=CzPA:1,6mMemFL It was adjusted to be PAPrn). Also, the film thickness of the electron transport layer 1117a of the light-emitting element 7 was The nm was set to 25nm.

[0244] Furthermore, the electron transport layer 1117a of the light-emitting element 7 is the same as the light-emitting element 5 shown in Example 2 above and comparatively The configuration is the same as that used for the light-emitting layer of the light-emitting element 6. That is, the light-emitting layer that emits blue light This configuration was used as the electron transport layer 1117a of the optical element 7.

[0245] Subsequently, bathophenanthroline (abbreviated as BPhen) is applied to the electron transport layer 1117 at a film thickness of 1 A film was deposited to a thickness of 5 nm to form the first electron injection layer 1119a.

[0246] Furthermore, lithium fluoride (LiF) is applied to the first electron injection layer 1119a to a thickness of 1 nm. A second electron injection layer 1119b was formed by deposition.

[0247] Finally, aluminum is used as the cathode 1103 on the second electron injection layer 1119b, with a value of 200 The light-emitting element 7 of this embodiment was fabricated by depositing a film thickness of nm.

[0248] (light-emitting element 8) The light-emitting element 8 differs from the light-emitting element 7 in its light-emitting layer 1115. Specifically, the light-emitting element 8 The light-emitting layer 1115 is made of 2mDBTBPDBq-II, PCBNBB, which was used in the light-emitting element 7. And instead of Ir(tppr)2dpm, use 2mDBTBPDBq-II, PCBNBB The following formulas were used: and Ir(tBuppm)2(acac).

[0249] Furthermore, the light-emitting layer 1115 of the light-emitting element 8 is made of 2mDBTBPDBq-II and PCBNBB Ir(tBuppm)2(acac) and are co-deposited and formed on the hole transport layer 1113. Here, 2mDBTBPDBq-II, PCBNBB, and Ir(tBuppm) The weight ratio of 2(acac) is 0.8:0.2:0.06 (=2mDBTBPDBq-II) It was adjusted so that it becomes :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] Furthermore, in the light-emitting layer 1115 of the light-emitting element 8, 2mDBTBPDBq-II is an electron transport It is a hole-transporting material and functions as a host material. Furthermore, PCBNBB is a hole-transporting material. It exists and functions as an assisting material. Also, Ir(tBuppm)2(acac) is It is an organometallic complex containing lysium and functions as a guest material.

[0251] Furthermore, the electron transport layer 1117a of the light-emitting element 8 is similar to that of the light-emitting element 7, as shown in the previous example 2. The configuration is the same as that used for the light-emitting layer of light-emitting element 5 and comparative light-emitting element 6. That is, the blue This configuration uses an emissive layer that emits light as the electron transport layer 1117a of the light-emitting element 8.

[0252] Furthermore, the light-emitting element 8 is manufactured in the same way as the light-emitting element 7, except for the light-emitting layer 1115. did.

[0253] Furthermore, the deposition process of the light-emitting element (light-emitting element 7 and light-emitting element 8) according to one aspect of the present invention described above is All of these were done using the resistance heating method.

[0254] The element structure of a light-emitting element (light-emitting element 7 and light-emitting element 8) according to one embodiment of the present invention obtained above The structure is shown in Table 4.

[0255] [Table 4]

[0256] As shown in Table 4, a light-emitting element according to one aspect of the present invention is made of a phosphorescent material (light-emitting element 7 and light-emitting element). 8) 2mDBTBPDBq-II is used as the host material. Also, the light-emitting element 7 The electron transport layer of the light-emitting element 8 uses a common CzPA and 1,6mMemFLPAPrn. It is.

[0257] Next, each of the light-emitting elements prepared above is exposed to the atmosphere inside a glove box with a nitrogen atmosphere. To prevent this, the device is sealed with a glass substrate (a sealing material is applied around the element, and when sealed...) The device was then heat-treated at 80°C for 1 hour. After that, the operating characteristics of each light-emitting element were measured. The measurements were taken at room temperature (in an atmosphere maintained at 25°C).

[0258] Figure 22 shows the current density-luminance characteristics of light-emitting elements 7 and 8, and Figure 23 shows the voltage-luminance characteristics. Figure 24 shows the luminance-current efficiency characteristics, Figure 25 shows the voltage-current characteristics, and Figure 2 shows the emission spectrum. These are shown in section 6.

[0259] In Figure 22, the horizontal axis represents current density (mA / cm²). 2 The vertical axis represents luminance (cd / m²). 2 In Figure 23, the horizontal axis represents voltage (V), and the vertical axis represents luminance (cd / m²). 2 ) In Figure 24, the horizontal axis represents luminance (cd / m²). 2 ), the vertical axis represents current efficiency (cd / A) In Figure 25, the horizontal axis represents voltage (V) and the vertical axis represents current (mA). In Figure 26, the horizontal axis represents wavelength (nm), and the vertical axis represents intensity (in arbitrary units).

[0260] Furthermore, the brightness of each light-emitting element is 1000 cd / m². 2 Voltage (V) and current density at the vicinity (mA / cm 2 ), CIE chromaticity coordinates (x, y), current efficiency (cd / A), external quantum efficiency ( The percentages are shown in Table 5.

[0261] [Table 5]

[0262] As shown in Table 5, the brightness of the light-emitting element 7 is 984 cd / m². 2 As for the element characteristics in this case, current effect The chromaticity is 27 cd / A, the external quantum efficiency is 25%, and the CIE chromaticity coordinates are (x,y) The values ​​were (0.66, 0.34). Also, the brightness of the light-emitting element 8 was 948 cd / m². 2 The element In terms of sub-characteristics, the current efficiency is 76 cd / A, the external quantum efficiency is 23%, and the CIE color is... The coordinate system was (x,y)=(0.44,0.56).

[0263] Furthermore, as shown in Figure 26, the emission spectra of light-emitting elements 7 and 8 are 6 It has peaks at 20 nm and 548 nm. Furthermore, the electron transport layer used was 1.6 mM It can be seen that the blue light emission from FLPAPrn (see Figure 21) was not observed.

[0264] As described above, the light-emitting element 7 in one aspect of the present invention has a blue electron transport layer 1117a. Even when using an emissive layer that exhibits light emission, device characteristics equivalent to those of the light-emitting element 1 shown in Example 2 were obtained. Furthermore, in one embodiment of the present invention, the light-emitting element 8 exhibits blue light emission as the electron transport layer 1117a. Even when using a light-emitting layer, device characteristics equivalent to those of the light-emitting element 3 shown in Example 2 were obtained.

[0265] Therefore, the electrons of the host material (CzPA) of the fluorescent material used in the electron transport layer 1117a Electron transport material (2mDBTBPDBq-I) is a host material for electron transport and phosphorescent materials. I) Due to its high electron transport properties, the light-emitting region of this light-emitting element is the hole transport layer of the light-emitting layer 1115. Light is formed in the region near 1113 and excited by the light-emitting layer 1115, and then emitted from the electron transport layer 1117 It was confirmed that the element configuration does not diffuse to side a, or diffuses very little. The electron transport layer 1117a used in element 7 and light-emitting element 8 contains a fluorescent material, 1.6 mM It contains emFLPAPrn. However, as shown in Figures 22 to 26, fluorescence The material 1,6mMemFLPAPrn was confirmed not to affect the device characteristics. It was done.

[0266] Note that the configuration shown in this embodiment is not the same as the configuration shown in other embodiments or the configuration shown in other embodiments. It can be used in appropriate combination with other elements. [Examples]

[0267] In this embodiment, the light-emitting element according to one aspect of the present invention, which was fabricated in Example 2 and Example 3, is a light-emitting element. Element 1, light-emitting element 3, light-emitting element 7, and light-emitting element 8, and a comparison light-emitting element for comparison. Reliability tests were conducted on element 2 and the comparative light-emitting element 4. The results of the reliability tests are shown in Figure 27. (A) and (B) are shown.

[0268] Figure 27(A) shows light-emitting element 1, comparison light-emitting element 2, and light-emitting element 7, i.e., the red element. These are the reliability test results. Also, Figure 27(B) shows the light-emitting element 3, the comparative light-emitting element 4, and the These are the reliability test results for optical element 8, i.e., the green element. Note that Figures 27(A) and (B) show the results. In the reliability test, the measurement method is to set the initial brightness to 5000 cd / m². 2 Set to, current density - Each light-emitting element was driven under specific conditions. The horizontal axis represents the driving time (h) of the element, and the vertical axis represents the initial brightness. This represents the normalized brightness (%) when set to 00%. Also, in Figures 27(A) and (B), each The data from the optical elements roughly overlap.

[0269] From the results in Figure 27(A), the normalized brightness of the light-emitting element 1 after 357 hours was 68%. Furthermore, the normalized brightness of comparison light-emitting element 2 after 357 hours was 68%. The normalized brightness of the light-emitting element 7 after 357 hours was 66%. Also, Figure 27(B) Based on the results, the normalized brightness of the light-emitting element 3 after 688 hours was 81%. The normalized brightness of the comparison light-emitting element 4 after 688 hours was 82%. The normalized brightness after 688 hours was 80%.

[0270] As described above, the light-emitting element 1 and light-emitting element 7, according to one aspect of the present invention, are compared with the comparative light-emitting element 2. The results of the reliability tests were equivalent. Furthermore, the light-emitting element 3 and light-emitting element, which are embodiments of the present invention, are also shown. Value 8 was equivalent to the reliability test result of comparative light-emitting element 4.

[0271] Note that the configuration shown in this embodiment is not the same as the configuration shown in other embodiments or the configuration shown in other embodiments. It can be used in appropriate combination with other elements. [Explanation of Symbols]

[0272] 100 circuit boards 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 The fourth hole transport layer 115 Emitting layer 115a First light-emitting layer 115b Second light-emitting layer 115c Third luminescent 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 materials 142a Third electron transport material 200 circuit boards 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 luminescent layer 217 Electron transport layer 219 Electron injection layer 250 Light-emitting devices 251a Bulkhead 251b Bulkhead 251c Bulkhead 251d Bulkhead 253 Semi-transparent / semi-reflective electrode 253a reflective electrode 253b reflective electrode 253c reflective electrode 260 Light-emitting devices 1100 circuit board 1101 Anode 1103 Cathode 1111 Hole injection layer 1113 Hole transport layer 1115 Emitting layer 1117 Electron transport layer 1117a Electron transport layer 1119a Electron injection layer 1119b Electron injection layer 7100 Television equipment 7101 enclosure 7103 Display section 7105 Stand 7107 Display section 7109 Operation Keys 7110 Remote Control Unit 7201 Main Unit 7202 enclosure 7203 Display section 7204 Keyboard 7205 External connection port 7206 Pointing device 7301 enclosure 7302 enclosure 7303 Connection section 7304 Display section 7305 Display section 7306 Speaker section 7307 Recording media insertion section 7308 LED Lamp 7309 Operation Keys 7310 Connection terminal 7311 Sensor 7312 Microphone 7400 mobile phones 7401 enclosure 7402 Display section 7403 Operation Buttons 7404 External connection port 7405 Speaker 7406 Microphone 7501 Lighting Department 7502 Umbrella 7503 Variable Arm 7504 Post 7505 units 7506 Power supply

Claims

1. It has a first light-emitting element, a second light-emitting element, and a third light-emitting element, The first light-emitting element is The first layer and, The second layer above the first layer, The first common layer is located above the second layer, The second layer comprises a first phosphorescent material, a first organic compound, and a second organic compound. The second light-emitting element described above is The third layer, The fourth layer above the third layer, The first common layer is located above the fourth layer, The fourth layer comprises a second phosphorescent material, a third organic compound, and a fourth organic compound. The third light-emitting element described above is The fifth layer, The first common layer is located above the fifth layer, The fifth layer comprises a fluorescent material and a fifth organic compound. The first common layer has regions that are in contact with each of the second layer, the fourth layer, and the fifth layer. The first organic compound and the second organic compound are a combination that forms an excited complex. A light-emitting device wherein the emission spectrum of the excited complex overlaps with the absorption spectrum of the first phosphorescent material.

2. It has a first light-emitting element, a second light-emitting element, and a third light-emitting element, The first light-emitting element is The first layer and, The second layer above the first layer, The first common layer is located above the second layer, The second layer comprises a first phosphorescent material, a first organic compound, and a second organic compound. The second light-emitting element described above is The third layer, The fourth layer above the third layer, The first common layer is located above the fourth layer, The fourth layer comprises a second phosphorescent material, a third organic compound, and a fourth organic compound. The third light-emitting element described above is The fifth layer, The first common layer is located above the fifth layer, The fifth layer comprises a fluorescent material and a fifth organic compound. The first common layer has regions that are in contact with each of the second layer, the fourth layer, and the fifth layer. The first organic compound is a π-electron-deficient heteroaromatic compound, The second organic compound is a π-electron-rich heteroaromatic compound or an aromatic amine compound, The fifth organic compound is an organic compound containing an anthracene skeleton, The first organic compound and the second organic compound are a combination that forms an excited complex. A light-emitting device wherein the emission spectrum of the excited complex overlaps with the absorption spectrum of the first phosphorescent material.

3. It has a first light-emitting element that emits red light, a second light-emitting element that emits green light, and a third light-emitting element that emits blue light. The first light-emitting element is The first layer and, The second layer above the first layer, The first common layer is located above the second layer, The second light-emitting element described above is The third layer, The fourth layer above the third layer, The first common layer is located above the fourth layer, The third light-emitting element described above is The fifth layer, The first common layer is located above the fifth layer, The first common layer has regions that are in contact with each of the second layer, the fourth layer, and the fifth layer. At least one of the second layer and the fourth layer comprises a first organic compound, a second organic compound, and a light-emitting material. The first organic compound and the second organic compound are a combination that forms an excited complex. A light-emitting device wherein the emission spectrum of the excited complex overlaps with the absorption spectrum of the light-emitting substance.

4. It has a first light-emitting element that emits red light, a second light-emitting element that emits green light, and a third light-emitting element that emits blue light. The first light-emitting element is The first layer and, The second layer above the first layer, The first common layer is located above the second layer, The second light-emitting element described above is The third layer, The fourth layer above the third layer, The first common layer is located above the fourth layer, The third light-emitting element described above is The fifth layer, The first common layer is located above the fifth layer, The first common layer has regions that are in contact with each of the second layer, the fourth layer, and the fifth layer. At least one of the second layer and the fourth layer comprises a first organic compound, a second organic compound, and a light-emitting material. The first organic compound and the second organic compound are a combination that forms an excited complex. The emission spectrum of the excited complex overlaps with the absorption spectrum of the luminescent substance. The first organic compound is a π-electron-deficient heteroaromatic compound, The second organic compound is a π-electron-rich heteroaromatic compound or an aromatic amine compound, The fifth layer is a light-emitting device having an organic compound having an anthracene skeleton.

5. In claim 3 or claim 4, The second layer comprises the first organic compound, the second organic compound, and the light-emitting material. The aforementioned light-emitting material is a phosphorescent material, The fifth layer is a light-emitting device having a fluorescent material.

6. In claim 3 or claim 4, The fourth layer comprises the first organic compound, the second organic compound, and the light-emitting material. The aforementioned light-emitting material is a phosphorescent material, The fifth layer is a light-emitting device having a fluorescent material.

7. In any one of claims 1 to 6, A light-emitting device wherein the triplet excitation energy level of the organic compound in the first common layer is lower than the triplet excitation energy level of the first organic compound.

8. In any one of claims 1 to 6, The third light-emitting element further has a sixth layer, The fifth layer is a light-emitting device located between the first common layer and the sixth layer.

9. In any one of claims 1 to 6, The first light-emitting element, the second light-emitting element, and the third light-emitting element further have a second common layer, The first layer is located between the second common layer and the second layer. The third layer is located between the second common layer and the fourth layer. The fifth layer is a light-emitting device located between the second common layer and the first common layer.

10. In any one of claims 1 to 6, The first light-emitting element, the second light-emitting element, and the third light-emitting element further have a second common layer, The first layer is located between the second common layer and the second layer. The third layer is located between the second common layer and the fourth layer. The light-emitting device wherein the second common layer has a region in contact with the fifth layer.

11. In any one of claims 1 to 6, The first light-emitting element and the second light-emitting element further have a second common layer, The third light-emitting element further comprises a sixth layer and the second common layer, The first layer is located between the second common layer and the second layer. The third layer is located between the second common layer and the fourth layer. The sixth layer is a light-emitting device located between the second common layer and the fifth layer.

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