Light-emitting element

Abstract

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

Description

Technical Field

[0001] One aspect of the present invention relates to a light-emitting device having a novel electron injection layer. Or it relates to a display device, an electronic device, and a lighting device having the light-emitting device. Note that one aspect of the present invention is not limited to the above technical field. The technical field of one aspect of the invention disclosed in this specification and the like relates to an article, a method, or a manufacturing method. Or one aspect of the present invention

[0002] relates to a process, a machine, a manufacture, or a composition of matter. Therefore, more specifically, the technical field of one aspect of the present invention disclosed in this specification includes, as an example, a semiconductor device, a display device, a liquid crystal display device, a light-emitting device, a lighting device, a power storage device, a storage device, a driving method thereof, or a manufacturing method thereof.

Background Art

[0003] In recent years, research and development of light-emitting devices using electroluminescence (EL) has been actively carried out. The basic configuration of these light-emitting devices is a configuration in which a layer containing a light-emitting substance (EL layer) is sandwiched between a pair of electrodes. By applying a voltage between the electrodes of this device, light emission from the light-emitting substance can be obtained.

[0004] Since the above-described light-emitting device is a self-luminous type, a display device using this device has advantages such as excellent visibility, no need for a backlight, low power consumption, and the like. Furthermore, it also has advantages such as being able to be manufactured in a thin and lightweight manner and having a high response speed.

[0005] Generally, in order to reduce the driving voltage of a light-emitting device, an electron injection layer is provided between the cathode and the light-emitting layer This is because the electron injection layer reduces the electron injection barrier with the cathode, and thus metals or their compounds with low work functions, such as alkali metals and alkaline earth metals typified by lithium (Li) and calcium (Ca), are used (for example, Patent Document 1).

[0006] When the above light-emitting element is used in a light-emitting device, there are a method of providing an EL layer having a function of emitting light of mutually different colors to each sub-pixel in a pixel (hereinafter referred to as a dot painting method), and a method of providing a common EL layer having a function of emitting, for example, white light to the sub-pixels in a pixel and providing color filters having functions of transmitting light of mutually different colors to each sub-pixel (hereinafter referred to as a color filter method).

[0007] The advantages of the color filter method are that since the EL layer can be made common for all the pixels, the loss of the material of the EL layer is small as compared with the dot painting method, and the process required for forming the EL layer can be reduced, so that the light-emitting device can be manufactured at low cost with high productivity. Next, in the dot painting method, a margin is required between each sub-pixel in order to prevent the materials of the EL layers of each sub-pixel from mixing with each other, whereas in the color filter method, such a margin is unnecessary, so that it is possible to realize a light-emitting device with higher pixel density and higher definition.

[0008] The above light-emitting element can provide various emission colors depending on the type of the light-emitting substance contained in the EL layer. When considering application to a lighting device, a high-efficiency light-emitting element that emits white light or a color close thereto is required. Also, when considering application to a light-emitting device using the color filter method, a high-efficiency light-emitting element that emits light with high color purity is required. Also, ​​​​​​​​​​​Light emitting elements used in these devices are required to have low power consumption.

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

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

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

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

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

[0014] In addition, a high electron injection property is required for an electron injection layer adjacent to a charge generation layer of a tandem element. . Therefore, an alkali metal such as lithium or cesium, a compound thereof, an alkaline earth metal such as calcium, or a compound thereof is used for the electron injection layer. However, when the metal and the compound are used for the electron injection layer, the metal may be dispersed in the electron transport layer, which may cause crosstalk. Regarding the above problems, in one aspect of the present invention, an object is to provide a light-emitting element with a low driving voltage. Or, in one aspect of the present invention, an object is to provide a light-emitting element with high moisture resistance. Or, in one aspect of the present invention, an object is to provide a light-emitting element with high oxidation resistance. Or, in one aspect of the present invention, an object is to provide a light-emitting element with reduced power consumption. Or, in one aspect of the present invention, an object is to provide a highly reliable light-emitting element. Or, in one aspect of the present invention, an object is to provide a novel light-emitting element. Further, one aspect of the present invention is to provide a novel semiconductor device. Or, in one aspect of the present invention, an object is to provide a light-emitting element in which the occurrence of crosstalk is suppressed. Or, in one aspect of the present invention, an object is to provide a light-emitting element that exhibits high color purity light emission. is required.

[0015] Or, in one aspect of the present invention, an object is to provide a highly moisture-resistant electronic device and lighting device to which the above light-emitting element is applied. Or, in one aspect of the present invention, an object is to provide a consumption Or, in one aspect of the present invention, an object is to provide a highly moisture-resistant electronic device and lighting device to which the above light-emitting element is applied. Or, in one aspect of the present invention, an object is to provide a consumption Or, in one aspect of the present invention, an object is to provide a highly moisture-resistant electronic device and lighting device to which the above light-emitting element is applied. Or, in one aspect of the present invention, an object is to provide a consumption Or, in one aspect of the present invention, an object is to provide a highly moisture-resistant electronic device and lighting device to which the above light-emitting element is applied. Or, in one aspect of the present invention, an object is to provide a consumption Or, in one aspect of the present invention, an object is to provide a highly moisture-resistant electronic device and lighting device to which the above light-emitting element is applied. Or, in one aspect of the present invention, an object is to provide a consumption Or, in one aspect of the present invention, an object is to provide a highly moisture-resistant electronic device and lighting device to which the above light-emitting element is applied. Or, in one aspect of the present invention, an object is to provide a consumption Or, in one aspect of the present invention, an object is to provide a highly moisture-resistant electronic device and lighting device to which the above light-emitting element is applied. Or, in one aspect of the present invention, an object is to provide a consumption Or, in one aspect of the present invention, an object is to provide a highly moisture-resistant electronic device and lighting device to which the above light-emitting element is applied. Or, in one aspect of the present invention, an object is to provide a consumption Or, in one aspect of the present invention, an object is to provide a highly moisture-resistant electronic device and lighting device to which the above light-emitting element is applied. Or, in one aspect of the present invention, an object is to provide a consumption is required.

[0016] Or, in one aspect of the present invention, an object is to provide a highly moisture-resistant electronic device and lighting device to which the above light-emitting element is applied. Or, in one aspect of the present invention, an object is to provide a consumption Or, in one aspect of the present invention, an object is to provide a highly moisture-resistant electronic device and lighting device to which the above light-emitting element is applied. Or, in one aspect of the present invention, an object is to provide a consumption An object of the present invention is to provide a light-emitting device with reduced power consumption. Or, one aspect of the present invention is Another object of the present invention is to provide a long-life light-emitting device applying the above light-emitting element.

[0017] Note that the description of the above problems does not prevent the existence of other problems. One aspect of the present invention does not necessarily need to solve all of these problems. Other problems than the above will be apparent from the description in the specification and the like, and it is possible to extract other problems than the above from the description in the specification and the like. It is obvious.

Means for Solving the Problems

[0018] One aspect of the present invention has a light-emitting layer between an anode and a cathode, and has a first layer between the light-emitting layer and the cathode. The first layer includes a first organic compound having a lone pair of electrons and a transition metal, and the first organic compound and the transition metal form a SOMO (Single Occupied Molecular Orbital). It is a light-emitting element. One aspect of the present invention has a first light-emitting unit and a second light-emitting unit between an anode and a cathode, has a first layer between the first light-emitting unit and the second light-emitting unit, and the first layer includes a first organic compound and a transition metal. The first organic compound has a lone pair of electrons, and the first organic compound and the transition metal form a SOMO. It is a light-emitting element. One aspect of the present invention has a first light-emitting unit and a second light-emitting unit between an anode and a cathode, has a first layer and a charge generation layer between the first light-emitting unit and the second light-emitting unit, the first layer and the charge generation layer are provided in contact with each other, and the first layer includes a first organic compound.

[0019] One aspect of the present invention has a first light-emitting unit and a second light-emitting unit between an anode and a cathode, has a first layer and a charge generation layer between the first light-emitting unit and the second light-emitting unit, the first layer and the charge generation layer are provided in contact with each other, and the first layer includes a first organic compound. One aspect of the present invention has a first light-emitting unit and a second light-emitting unit between an anode and a cathode, has a first layer between the first light-emitting unit and the second light-emitting unit, and the first layer includes a first organic compound and a transition metal. The first organic compound has a lone pair of electrons, and the first organic compound and the transition metal form a SOMO. It is a light-emitting element. One aspect of the present invention has a first light-emitting unit and a second light-emitting unit between an anode and a cathode, has a first layer and a charge generation layer between the first light-emitting unit and the second light-emitting unit, the first layer and the charge generation layer are provided in contact with each other, and the first layer includes a first organic compound. One aspect of the present invention has a first light-emitting unit and a second light-emitting unit between an anode and a cathode, has a first layer and a charge generation layer between the first light-emitting unit and the second light-emitting unit, the first layer and the charge generation layer are provided in contact with each other, and the first layer includes a first organic compound.

[0020] One aspect of the present invention has a first light-emitting unit and a second light-emitting unit between an anode and a cathode, has a first layer and a charge generation layer between the first light-emitting unit and the second light-emitting unit, the first layer and the charge generation layer are provided in contact with each other, and the first layer includes a first organic compound. One aspect of the present invention has a first light-emitting unit and a second light-emitting unit between an anode and a cathode, has a first layer and a charge generation layer between the first light-emitting unit and the second light-emitting unit, the first layer and the charge generation layer are provided in contact with each other, and the first layer includes a first organic compound. One aspect of the present invention has a first light-emitting unit and a second light-emitting unit between an anode and a cathode, has a first layer and a charge generation layer between the first light-emitting unit and the second light-emitting unit, the first layer and the charge generation layer are provided in contact with each other, and the first layer includes a first organic compound. ​​and has a first transition metal, the first organic compound has a lone pair of electrons, the first organic compound and the first transition metal form a SOMO, which is a light-emitting element.

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

[0022] Also, in the above configuration, it is preferable that the number of carbon atoms constituting the first organic compound is 25 or more and 100 or less. It is preferable.

[0023] Also, in the above configuration, it is preferable that the first organic compound does not have a 1,10-phenanthroline skeleton. It is preferable.

[0024] Also, in the above configuration, the LUMO (Lowest Unoccupied Molecular Orbital) level of the first organic compound is preferably -3.6 eV or higher and -2.3 eV or lower. It is preferable.

[0025] Also, in the above configuration, it is preferable that the transition metal belongs to any of Group 5, Group 7, Group 9, or Group 1 1 in the periodic table. It is more preferable that the transition metal belongs to Group 11, and Ag is even more preferable.

[0026] Also, in the above configuration, it is preferable to further have a second layer between the cathode and the first layer, and the second layer contains a second organic compound having an electron deficient heteroaromatic ring.

[0027] In the above configuration, it is preferable that the LUMO level of the second organic compound is lower than the SOMO level. It is preferable.

[0028] In the above configuration, it is preferable that the light-emitting element does not contain an alkali metal and an alkaline earth metal. Preferably.

[0029] In the above configuration, it is preferable that the molar ratio of the metal in the first layer is 0.2 or more and 0.8 or less with respect to the first organic compound. .2 or more and 0.8 or less is preferable.

[0030] In the above configuration, it is preferable that the cathode contains the same substance as the metal in the first layer. Or , it is preferable that the light-emitting layer contains the first organic compound.

[0031] Another aspect of the present invention is an electronic device having at least one of the display device having each of the above configurations and a housing or a touch sensor. Another aspect of the present invention is a lighting device having at least one of the light-emitting elements having each of the above configurations and a housing or a touch sensor. Another aspect of the present invention includes not only a light-emitting device having a light-emitting element but also an electric device having a light-emitting device within the scope. Therefore, the light-emitting device in this specification refers to an image display device or a light source (including a lighting device). In addition, a display module in which a connector, for example, an FPC (Flexible Printed Circuit) or a TCP (Tape Carrier Package) is attached to the light-emitting element, a display module in which a printed wiring board is provided at the tip of the TCP, or a display module in which an IC (integrated circuit) is directly mounted on the light-emitting element by a COG (Chip On Glass) method is also an aspect of the present invention. Preferably. Preferably. Preferably. Preferably. Preferably. ble Printed Circuit) or a TCP (Tape Carrier Package) is attached, a display module in which a printed wiring board is provided at the tip of the TCP, or a display module in which an IC (integrated circuit) is directly mounted on the light-emitting element by a COG (Chip On Glass) method is also an aspect of the present invention. Preferably. Preferably.

Effects of the Invention

[0032] According to one aspect of the present invention, a light-emitting element with a low driving voltage can be provided. Further, the present invention According to one aspect of the present invention, a light-emitting device with high moisture resistance can be provided. Also, according to one aspect of the present invention, a light-emitting device with high oxidation resistance can be provided. Also, according to one aspect of the present invention, a light-emitting device with reduced power consumption can be provided. Also, according to one aspect of the present invention, a highly reliable light-emitting device can be provided. Also, according to one aspect of the present invention, a novel light-emitting device can be provided. Also, according to one aspect of the present invention, a novel semiconductor device can be provided. Also, according to one aspect of the present invention, a light-emitting device with suppressed crosstalk can be provided. Also, according to one aspect of the present invention, a light-emitting device that exhibits high color purity of light can be provided.

[0033] Also, according to one aspect of the present invention, an electronic device and a lighting device with high moisture resistance to which the above light-emitting device is applied can be provided. Also, according to one aspect of the present invention, a light-emitting device with reduced power consumption to which the above light-emitting device is applied can be provided. According to one aspect of the present invention, a long-life light-emitting device to which the above light-emitting device is applied can be provided.

[0034] Note that the description of these effects does not prevent the existence of other effects. Note that one aspect of the present invention does not necessarily have to have all of these effects. Note that other effects can be clearly understood from the descriptions in the specification, drawings, claims, etc., and it is possible to extract these other effects from the descriptions in the specification, drawings, claims, etc.

Brief Description of the Drawings

[0035]

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MODE FOR CARRYING OUT THE INVENTION

[0036] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is as follows Without being limited to the description, the form and details can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention is not construed as being limited to the description of the embodiments shown below.

[0037] In addition, the position, size, range, etc. of each component shown in the drawings, etc. may not represent the actual position, size, range, etc. for the sake of easy understanding. For this reason, the disclosed invention is not necessarily limited to the position, size, range, etc. disclosed in the drawings, etc.

[0038] Also, in this specification, etc., the ordinal numbers attached as the first, second, etc. are used for convenience and may not indicate the process order or the stacking order. Therefore, for example, "the first" can be appropriately replaced with "the second" or "the third", etc. and described. Also, the ordinal numbers described in this specification, etc. and the ordinal numbers used to specify an aspect of the present invention may not match.

[0039] Also, in this specification, etc., when explaining the configuration of the invention using the drawings, the reference signs indicating the same components are commonly used among different drawings.

[0040] Also, in this specification, etc., the term "film" and the term "layer" can be mutually replaced. For example, the term "conductive layer" may be changed to the term "conductive film". Or, for example, the term "insulating film" may be changed to the term "insulating layer".

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

[0042] <Configuration Example 1 of Light-Emitting Element> FIG. 1(A) is a schematic cross-sectional view of a light-emitting element 150 according to one embodiment of the present invention.

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

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

[0045] In the present embodiment, among the pair of electrodes, electrode 101 is described as the anode and electrode 102 is described as the cathode. However, the configuration of the light-emitting element 150 is not limited to this. That is, electrode 101 may be the cathode, electrode 102 may be the anode, and the lamination of each layer between the electrodes may be in the reverse order. That is, from the anode side, the hole injection layer 111, the hole transport layer 112, the light-emitting layer 140, the electron transport layer 118, and the electron injection layer 130 may be laminated in this order.

[0046] Note that the configuration of the EL layer 100 is not limited to the configuration shown in FIG. 1(A), and has at least a light-emitting layer 140 and an electron injection layer 130, and may or may not have a hole injection layer 111, a hole transport layer 112, and an electron transport layer 118.

[0047] In addition, in the EL layer between the pair of electrodes, each layer may be formed according to its function, and is not limited to this. That is, the EL layer between the pair of electrodes reduces the injection barrier of holes or electrons. ​​​​​​​​, a layer having a function such as improving the hole or electron transport property, inhibiting the hole or electron transport property, or suppressing the quenching phenomenon by the electrode, etc. may be used. It may also be configured to have a layer having a function such as being able to suppress the quenching phenomenon by the electrode. .

[0048] Further, the light-emitting layer 140 preferably has a host material and a guest material (light-emitting material). Yes.

[0049] Further, as the host material, a material having a function of transporting holes (hole transporting property) (hole transporting material), and a material having a function of transporting electrons (electron transporting property) (electron transporting material) are preferably used alone or in combination, and a material having both hole transporting property and electron transporting property may also be used. That is, either one or both of them may be used, and a material having both hole transporting property and electron transporting property may be used. It is preferable to use either one or both of them, and a material having both hole transporting property and electron transporting property may also be used. Yes.

[0050] Further, when the host material is a combination of an electron transporting material and a hole transporting material, the carrier balance can be easily controlled by the mixing ratio thereof. Specifically, the range of electron transporting material: hole transporting material = 1:9 to 9:1 (weight ratio) is preferable. Also, since the carrier balance can be easily controlled by having this configuration, the control of the carrier recombination region can also be easily performed. That is, the range of electron transporting material: hole transporting material = 1:9 to 9:1 (weight ratio) is preferable. Also, since the carrier balance can be easily controlled by having this configuration, the control of the carrier recombination region can also be easily performed. Yes.

[0051] Further, as the guest material, a light-emitting compound may be used, and as the light-emitting compound, a substance capable of emitting fluorescence (hereinafter, also referred to as a fluorescent compound) or a substance capable of emitting phosphorescence (hereinafter, also referred to as a phosphorescent compound) is preferably used. Yes.

[0052] In order to reduce the driving voltage of the light-emitting element, it is necessary to reduce the electron injection barrier between the light-emitting layer 140 and the electrode 102. Therefore, an electron injection layer is provided between the light-emitting layer 140 and the electrode 102. Yes. It is preferable to provide 130. In conventional light-emitting elements, a metal material having an alkali metal or an alkaline earth metal with a small work function is used for the electron injection layer 130. However, since a metal material with a small work function has high reactivity with oxygen and water, when used in a light-emitting element, it may cause a decrease in luminous efficiency, an increase in driving voltage, a decrease in element lifetime, and the occurrence of shrinkage (non-light-emitting region at the end of the light-emitting part), which may lead to a decrease in the characteristics and reliability of the light-emitting element. In other words, a metal material with a small work function can be a factor in element deterioration. Therefore, in order to suppress a decrease in the characteristics and reliability of the light-emitting element, it is preferable that the light-emitting element does not contain an alkali metal and an alkaline earth metal. On the other hand, although a metal with a large work function has low reactivity with oxygen and water, when used in the electron injection layer 130, it forms an electron injection barrier with the electrode 102, resulting in problems such as an increase in the driving voltage of the light-emitting element and a decrease in luminous efficiency.

[0053] Here, the inventors have found that by forming a SOMO through the interaction between a compound having a lone pair of electrons and a transition metal, and using a composite material of the compound and the transition metal that forms the SOMO for the electron injection layer, the electron injection barrier between the electron injection layer and the cathode can be reduced, and a light-emitting element with excellent moisture resistance can be obtained. To form a SOMO by the interaction between a compound having a lone pair of electrons and a transition metal,

[0054] it is preferable that the total number of electrons of the compound and the transition metal is odd. Therefore, when the number of electrons of the compound is even, the transition metal is preferably in an odd group in the periodic table. it is preferable that the transition metal is in an odd group in the periodic table. A light-emitting element with excellent moisture resistance can be obtained.

[0055] Since a SOMO is formed by the interaction between a compound having a lone pair of electrons and a transition metal, it is preferable that the total number of electrons of the compound and the transition metal is odd. Therefore, when the number of electrons of the compound is even, the transition metal is preferably in an odd group in the periodic table. In addition, when the number of electrons of the compound is odd, the transition metal is preferably in an even group in the periodic table. It is preferable that

[0056] In addition, as the compound having an unshared electron pair, an organic compound having a function of transporting electrons is preferred. Further, an organic compound that functions as an electron acceptor with respect to the transition metal is preferred.

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

[0058] Since the transition metal has poor reactivity with water and oxygen, when used in a light-emitting element, there is less concern about element degradation due to water and oxygen compared to the case of using a metal with a small work function. Therefore, one embodiment of the present invention can provide a light-emitting element excellent in moisture resistance and oxidation resistance. It can provide a light-emitting element excellent in moisture resistance and oxidation resistance.

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

[0060] FIG. 1(C) shows an energy diagram of the electron injection layer 130 in the light-emitting element of one embodiment of the present invention. When the transition metal 132 and the compound 131 are mixed, a SOMO is formed by the compound 131 interacting with the atoms of the transition metal 132. At this time, the HOMO (Highest Occupied Molecular Orbital) level formed by the compound 131 interacting with the atoms of the transition metal 132 is preferably the same as the HOMO level of the original compound 131. The organic compound having a function of transporting electrons to the compound 131 When the transition metal 132 and the compound 131 are mixed, a SOMO is formed by the compound 131 interacting with the atoms of the transition metal 132. At this time, the HOMO (Highest Occupied Molecular Orbital) level formed by the compound 131 interacting with the atoms of the transition metal 132 is preferably the same as the HOMO level of the original compound 131. The organic compound having a function of transporting electrons to the compound 131 When the transition metal 132 and the compound 131 are mixed, a SOMO is formed by the compound 131 interacting with the atoms of the transition metal 132. At this time, the HOMO (Highest Occupied Molecular Orbital) level formed by the compound 131 interacting with the atoms of the transition metal 132 is preferably the same as the HOMO level of the original compound 131. The organic compound having a function of transporting electrons to the compound 131 When the transition metal 132 and the compound 131 are mixed, a SOMO is formed by the compound 131 interacting with the atoms of the transition metal 132. At this time, the HOMO (Highest Occupied Molecular Orbital) level formed by the compound 131 interacting with the atoms of the transition metal 132 is preferably the same as the HOMO level of the original compound 131. The organic compound having a function of transporting electrons to the compound 131 When the transition metal 132 and the compound 131 are mixed, a SOMO is formed by the compound 131 interacting with the atoms of the transition metal 132. At this time, the HOMO (Highest Occupied Molecular Orbital) level formed by the compound 131 interacting with the atoms of the transition metal 132 is preferably the same as the HOMO level of the original compound 131. The organic compound having a function of transporting electrons to the compound 131 When the transition metal 132 and the compound 131 are mixed, a SOMO is formed by the compound 131 interacting with the atoms of the transition metal 132. At this time, the HOMO (Highest Occupied Molecular Orbital) level formed by the compound 131 interacting with the atoms of the transition metal 132 is preferably the same as the HOMO level of the original compound 131. The organic compound having a function of transporting electrons to the compound 131 When using a compound, the HOMO level of Compound 131 is low, and it is difficult for holes to be injected into Compound 131. Therefore, when the HOMO level formed by the interaction between Compound 131 and the atoms of Transition Metal 132 is equivalent to the HOMO level of the original Compound 131, the hole injection barrier between the electron injection layer 130 and the electrode 102 increases. As a result, it is preferable because holes are less likely to escape from the electron injection layer 130 to the electrode 102 and the carrier balance in the light-emitting device can be improved. In addition, in this specification and the like, HOMO refers to the molecular orbital with the highest energy that is filled with electrons. Since the SOMO has only one electron, when a voltage is applied to the light-emitting device 150, the electrons in the SOMO become carriers in the light-emitting device and are transported to the electron transport layer 118 and the light-emitting layer 140. Also, it becomes possible to easily inject electrons from the electrode 102 into the electron injection layer 130. That is, when the electron injection layer 130 has a combination of materials that form the SOMO, electrons can be easily injected from the electrode 102 into the EL layer 100. Also, the SOMO level is preferably lower than the LUMO level of Compound 131. Therefore, it is preferable that the LUMO level of Compound 131 is high. Specifically, it is preferable that the LUMO level of Compound 131 is -3.6 eV or more and -2.3 eV or less. When an organic compound having such a LUMO level is mixed with a transition metal, the SOMO level formed by the interaction becomes a suitable level for electron injection, so the electron injection barrier between the electron injection layer 130 and the electrode 102 can be reduced. When the HOMO level formed by the interaction between Compound 131 and the atoms of Transition Metal 132 is equivalent to the HOMO level of the original Compound 131, the hole injection barrier between the electron injection layer 130 and the electrode 102 increases. As a result, it is difficult for holes to escape from the electron injection layer 130 to the electrode 102, and the carrier balance in the light-emitting device can be improved, which is preferable. As a result, it is difficult for holes to escape from the electron injection layer 130 to the electrode 102, and the carrier balance in the light-emitting device can be improved, which is preferable. In addition, in this specification and the like, HOMO refers to the molecular orbital with the highest energy that is filled with electrons. In addition, in this specification and the like, HOMO refers to the molecular orbital with the highest energy that is filled with electrons.

[0061] Since the SOMO has only one electron, when a voltage is applied to the light-emitting device 150, the electrons in the SOMO become carriers in the light-emitting device and are transported to the electron transport layer 118 and the light-emitting layer 140. Since the SOMO has only one electron, when a voltage is applied to the light-emitting device 150, the electrons in the SOMO become carriers in the light-emitting device and are transported to the electron transport layer 118 and the light-emitting layer 140. Also, it becomes possible to easily inject electrons from the electrode 102 into the electron injection layer 130. That is, when the electron injection layer 130 has a combination of materials that form the SOMO, electrons can be easily injected from the electrode 102 into the EL layer 100. Also, the SOMO level is preferably lower than the LUMO level of Compound 131. Therefore, it is preferable that the LUMO level of Compound 131 is high. Specifically, it is preferable that the LUMO level of Compound 131 is -3.6 eV or more and -2.3 eV or less. When an organic compound having such a LUMO level is mixed with a transition metal, the SOMO level formed by the interaction becomes a suitable level for electron injection. When an organic compound having such a LUMO level is mixed with a transition metal, the SOMO level formed by the interaction becomes a suitable level for electron injection. As a result, the electron injection barrier between the electron injection layer 130 and the electrode 102 can be reduced. As a result, the electron injection barrier between the electron injection layer 130 and the electrode 102 can be reduced.

[0062] In addition, the HOMO level and LUMO level of an organic compound are generally measured by CV (Cyclic Voltammetry). It is estimated by methods such as metrology, photoelectron spectroscopy, optical absorption spectroscopy, inverse photoelectron spectroscopy, etc. When comparing values between different compounds, it is preferable to use values estimated by the same measurement. Here, the above-mentioned transition metal preferably belongs to any one of Group 5, Group 7, Group 9, and Group 11. Among these transition metals of odd groups, metals having one electron (unpaired electron) in the outermost shell orbit are particularly preferable because they easily form SOMO with Compound 131.

[0063]

[0064] <Estimation of SOMO level in the interaction between transition metal 132 and Compound 131 by quantum chemical calculation> Here, for Compound 131 and transition metal 132 to form SOMO, Compound 131 needs to interact with transition metal 132. Therefore, quantum chemical calculations were performed on the stabilization energy when an organic compound interacts with various transition metal atoms and the level of SOMO formed when the organic compound interacts with a transition metal atom. The results are shown in Table 1. As the organic compound having non-bonding electron pairs, 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen) shown below was used.

[0065]

Chemical formula

[0066]

Table 1

[0067] As the quantum chemical calculation program, Gaussian09 was used. The calculation was performed on a high-performance...​​​​​​​​​​​ Performed using an Ormance computer (manufactured by SGI, ICE X). First, the organic compound The most stable structures in the ground state of the simple substance, the ground state of the transition metal simple substance, and the ground state of the composite material of the organic compound and the transition metal were calculated by the density functional theory (DFT). As the basis function, 6- 311G(d,p) and LanL2DZ were used, and B3LYP was used as the functional. Next, the stabilization energy was calculated from the difference between the total energy of the composite material of the organic compound and the transition metal and the sum of the total energies of the organic compound simple substance and the transition metal simple substance. That is, (Stabilization energy) = (Total energy of the composite material of the organic compound and the transition metal) - (Total energy of the organic compound simple substance) - (Total energy of the transition metal simple substance). Note that the total energy of D FT is represented by the sum of the potential energy, the electrostatic energy between electrons, the kinetic energy of electrons, and the exchange-correlation energy that includes all complex electron-electron interactions. In DF T, since the exchange-correlation interaction is approximated by a functional of the one-electron potential expressed by the electron density (the meaning of a function of a function), the calculation is highly accurate.

[0068] From Table 1, when manganese (Mn), a Group 7 transition metal, cobalt (Co), a Group 9 transition metal, copper (Cu), a Group 11 transition metal, silver (Ag ), and gold (Au) are used as the transition metals of the above composite material, the stabilization energy is a negative value. This indicates that when an organic compound with non-bonding electrons (NBPhen in this case) is mixed with a transition metal, the organic compound is more stable when interacting with the transition metal atoms than when not interacting. That is, from Table 1, when a transition metal is mixed with an organic compound having non-bonding electrons, ) ​​​​​​​When the organic compound is reacted with the transition metal, the organic compound interacts with the transition metal, and a composite material of the organic compound and the transition metal is stabilized. In addition, the HOMO and LUMO energies in Table 1 and Table 2 described later are The -levels are calculated values and may differ from the measured values.

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

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

[0071] On the other hand, considering the manufacturing process of the light-emitting element, generally, the EL layer of the light-emitting element, particularly the electron injection layer and the cathode are often formed by vacuum evaporation. At this time, as the material to be used, it is preferable to use a material that can be easily vacuum-evaporated, that is, a material with a low melting point. Here, Group 11 elements can be preferably used for vacuum evaporation because they have a lower melting point compared to Group 7 and Group 9 elements. Among the Group 11 elements, Ag is particularly preferable because it has a low melting point. Also, by using the vacuum evaporation method, it is possible to easily mix transition metal atoms and organic compounds, which is preferable.

[0072] In addition, Ag and Cu can also be used as the cathode material. By using the same material for the electron injection layer 130 and the electrode 1 02, the manufacturing of the light-emitting element can be easily carried out, which is preferable. Also, by using the same material for the electron injection layer 130 and the electrode 102, the adhesion between the electron injection layer 130 and the electrode 102 can be enhanced, and the reliability of the light-emitting element can be improved. In addition, the manufacturing cost of the light-emitting element can be reduced.

[0073] Next, as the compound 131 when Ag is used for the transition metal 132, the stabilization energy and the SOMO level in the case where the compound 131 and Ag atoms interact when various organic compounds having non-bonding electron pairs are used were estimated by quantum chemical calculations. The results are shown in Table 2. Also, the organic compounds used and their abbreviations are shown below. The calculation method of the quantum chemical calculation is the same as the calculation method used for the calculation in Table 1.

[0074]

Chemical Formula

[0075]

Table 2

[0076] As shown in Table 2, various organic compounds having lone pairs are mixed with a transition metal (Ag in this case). When this is done, since the stabilization energy takes a negative value, it can be seen that the composite material of the organic compound having a lone pair and the transition metal is stabilized by the interaction.

[0077] When Compound 131 interacts with a transition metal 132 atom, it is preferable that the transition metal 132 atom is an electron donor and Compound 131 is an electron acceptor. In this case, Compound 131 preferably has an electron-deficient heteroaromatic ring. In such a configuration, since Compound 131 easily accepts electrons, the stabilization energy when interacting with the atoms of transition metal 132 can be reduced. Further, since a compound having an electron-deficient heteroaromatic ring has good electron transport properties, when used in an electron injection layer, the driving voltage of the light-emitting device can be reduced, so it is preferable as Compound 131.

[0078] The electron-deficient heteroaromatic ring is preferably a nitrogen-containing heteroaromatic ring, more preferably having at least one of a pyridine ring, a diazine ring (pyrimidine ring, pyrazine ring, pyridazine ring), and a triazine ring. Since these rings are excellent in electrochemical stability, a light-emitting device with good reliability can be provided. Further, since they are excellent in electron transport properties, a light-emitting device with a reduced driving voltage can be provided. Note that the compound having the electron-deficient heteroaromatic ring may be a metal complex.

[0079] In addition, when an organic compound is used as Compound 131, the number of carbon atoms is preferably 25 or more and 100 or less. By having such a number of carbon atoms, an organic compound excellent in sublimability can be obtained. Therefore, thermal decomposition of the organic compound can be suppressed in vacuum deposition, and good material use efficiency can be obtained. Furthermore, the glass transition point (Tg) is preferably 100°C or higher. By using an organic compound having such a Tg in the EL layer, a light-emitting device excellent in heat resistance can be obtained.

[0080] From Tables 1 and 2, NBPhen, diquinoxalino[2,3-a:2’,3’-c]phenazine (abbreviation: HATNA), 2,4,6-tris[3’-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz) have a small stabilization energy when interacting with Ag atoms as compared with other organic compounds. The heterocycles of these compounds have conjugated double bonds arranged in the order of N-C-C-N across a plurality of heterocycles. When having such a bonding site, a chelate ring can be formed when Compound 131 and transition metal 132 interact (Compound 131 and transition metal 132 interact to form a ring structure). Therefore, when Compound 131 coordinates to transition metal 132 atoms, it is preferable to form a chelate ring because the stabilization energy becomes small.

[0081] In addition, the molar ratio of transition metal 132 to Compound 131 is preferably 0.1 or more and 10 or less, more preferably 0.2 or more and 2 or less, and even more preferably 0.2 or more and 0.8 or less with respect to Compound 131. At such a ratio, when transition metal 132 and Compound 1 By mixing 31, a light-emitting device having good electron injection properties can be provided. Chemically When the molar ratio of transition metal 132 is too small compared to the above ratio for compound 131, since the amount of compound 131 that interacts with transition metal 132 to form SOMO is small, the electron injection property may decrease. Also, when the molar ratio of transition metal 132 is too large compared to the above ratio, since the transmittance of electron injection layer 130 decreases, the luminous efficiency of the light-emitting device may decrease.

[0082] Also, the film thickness of electron injection layer 130 is preferably 3 nm or more, more preferably 5 nm or more. With such a configuration, a composite material in which transition metal 132 and compound 131 are mixed can function well. Also, the film thickness of electron injection layer 130 is preferably 50 nm or less, more preferably 20 nm or less, even more preferably 10 nm or less. With such a configuration, the influence of light absorption by electron injection layer 130 can be reduced, and a light-emitting device showing high luminous efficiency can be provided.

[0083] Next, when iron (Fe), which is a transition metal of an even group, is used as transition metal 132 and copper phthalocyanine (abbreviation: CuPc) is used as compound 131, the stabilization energy and SOMO level when compound 131 and transition metal 13 2 interacted were estimated by quantum chemical calculations. The results are shown in Table 3. Note that the calculation method for the quantum chemical calculations is the same as the calculation method used for the calculations shown in Table 1.

[0084]

Table 3

[0085] ​​​Copper phthalocyanine has an odd number of electrons and has an SO MO at an energy level lower than the HOMO level. As an organic compound having a lone pair of electrons from Table 3, when copper phthalocyanine is used and mixed with a transition metal of an even group (Fe in this case), the stabilization energy becomes a negative value. That is, it can be seen that an organic compound having a lone pair of electrons and a transition metal atom are stabilized by interacting with each other.

[0086] In addition, when copper phthalocyanine and Fe interact with each other, a SOMO of a composite material of copper phthalocyanine and Fe is formed. The energy level of the SOMO is located between the HOM O level and the LUMO level of copper phthalocyanine. Therefore, by using the composite material for the electron injection layer 130 it is possible to provide a light-emitting device excellent in electron injection properties.

[0087] <Configuration Example 2 of Light-Emitting Device> Next, a configuration example different from the light-emitting device 150 shown in FIG. 1 will be described below with reference to FIGS. 2(A) and (B).

[0088] FIG. 2 is a cross-sectional schematic view showing a light-emitting device according to an aspect of the present invention. In FIGS. 2(A) and ( B), portions having the same functions as the reference numerals shown in FIG. 1 may have the same hatch pattern and the reference numerals may be omitted. In addition, portions having the same functions may be given the same reference numerals and the detailed description thereof may be omitted.

[0089] The light-emitting device 152 shown in FIG. 2(A) has a pair of electrodes (electrode 101 and electrode 102) and has an EL layer 105 provided between the pair of electrodes. The EL layer 105 has at least a light-emitting layer 140 and an electron injection layer 130. Further, it has a buffer layer 117. The buffer layer 117 is provided between the electron injection layer 130 and the electrode 102.

[0090] Also, as shown in Fig. 2(A), the EL layer 105 has functional layers such as a hole injection layer 111, a hole transport layer 112, and an electron transport layer 118 in addition to the light emitting layer 140. has functional layers such as a hole injection layer 111, a hole transport layer 112, and an electron transport layer 118.

[0091] By providing the buffer layer 117 between the electrode 102 and the electron transport layer 118, the probability of the electron transport layer 118, the electron injection layer 130, the light emitting layer 140, etc. coming into contact with oxygen or moisture is reduced, so that an improvement in the moisture resistance and oxidation resistance of the light emitting device can be expected. can be expected.

[0092] In one aspect of the present invention, a composite material of the above-described compound 131 and transition metal 132 is used for the electron injection layer 130, and an organic compound having an electron-deficient heteroaromatic ring is used for the buffer layer 117. Since the electron-deficient heteroaromatic ring has excellent electron transport properties as described above, the driving voltage of the light emitting device can be reduced. as described above, the driving voltage of the light emitting device can be reduced. as described above, the driving voltage of the light emitting device can be reduced. can be reduced.

[0093] By sandwiching the buffer layer 117 between the electron injection layer 130 and the electrode 102, it is preferable because the energy barrier between the electrode 102 and the electron injection layer 130 can be reduced. Also, the film thickness of the buffer layer is preferably 1 nm or more and 20 nm or less. With such a configuration, the electron injection barrier can be reduced while maintaining high electron transport properties. while maintaining high electron transport properties. is preferably 1 nm or more and 20 nm or less. With such a configuration, the electron injection barrier can be reduced while maintaining high electron transport properties. can be reduced.

[0094] Also, the LUMO level of the organic compound used for the buffer layer 117 is preferably lower than the SOMO level formed in the electron injection layer 130. By adopting such a configuration, it is preferable because the electron injection barrier between the electron injection layer 130 and the electrode 102 can be reduced. formed in the electron injection layer 130. By adopting such a configuration, it is preferable because the electron injection barrier between the electron injection layer 130 and the electrode 102 can be reduced. can be reduced.

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

[0096] <Configuration Example 3 of Light Emitting Element> The light emitting element 154 shown in Fig. 2(B) has a pair of electrodes (electrode 101 and electrode 102) and has an EL layer 107 provided between the pair of electrodes. The EL layer 107 has at least a light emitting layer 140 and an electron injection layer 130. Furthermore, it has a charge generation layer 160. The charge generation layer 160 is provided between the electron injection layer 130 and the electrode 102.

[0097] In addition, the EL layer 107 shown in Fig. 2(B) has functional layers such as a hole injection layer 111, a hole transport layer 112, and an electron transport layer 118 in addition to the light emitting layer 140.

[0098] By providing the charge generation layer 160 between the electrode 102 and the electron transport layer 118, the amount of oxygen and moisture entering the electron transport layer 118, the electron injection layer 130, the light emitting layer 140, etc. decreases. Therefore, an improvement in the moisture resistance and oxidation resistance of the light emitting element can be expected.

[0099] As described above, in the case of a configuration where the charge generation layer 160 has a hole transporting material and an electron accepting material, when a metal material having an alkali metal or an alkaline earth metal with a small work function is used for the electron injection layer 130, the electron accepting material of the charge generation layer 160 extracts electrons from the material used for the electron injection layer 130. Therefore, near the interface between the charge generation layer 160 and the electron injection layer 130, a depletion layer is generated. Therefore, the driving voltage may increase. In order to suppress the depletion layer, a layer having a function of transferring electrons is provided between the electron injection layer 130 and the charge generation layer 160. As a result, the driving voltage may increase. To suppress the depletion layer, a layer having a function of transferring electrons between the electron injection layer 130 and the charge generation layer 160 is provided. was necessary.

[0100] On the other hand, in the light-emitting element of one aspect of the present invention, by using a composite material of a transition metal and a compound having a non-bonding electron pair in the electron injection layer 130, it is difficult for the electron-accepting material in the charge generation layer 160 to extract electrons. Therefore, since the charge generation layer 160 can be provided without generating the depletion layer described above, a light-emitting element with a small number of stacked layers and a low driving voltage can be manufactured.

[0101] In addition, the film thickness of the charge generation layer 160 is not particularly limited and can be adjusted as appropriate. For example, by adjusting the film thickness from the light-emitting layer 140 to the electrode 102, the light obtained from the light-emitting layer 140 can be efficiently extracted outside the light-emitting element. That is, by adjusting the film thickness of the charge generation layer 160, the light extraction efficiency can be improved.

[0102] Also, it is preferable that the charge generation layer 160 and the electrode 102 are provided in contact with each other. With this configuration, the electron injection barrier between the electrode 102 and the EL layer 107 can be suppressed, so that the driving voltage of the light-emitting element can be reduced. Furthermore, it is more preferable that the charge generation layer 160 and the electron injection layer 130 are in contact with each other. As described above, in one aspect of the present invention, since a light-emitting element with a low driving voltage can be manufactured even when the charge generation layer 160 and the electron injection layer 130 are in contact with each other, with this configuration, the number of stacked layers of the EL layer 107 can be suppressed.

[0103] In addition, as the electron-accepting material included in the charge generation layer 160, a transition metal oxide can be preferably used. Examples of the transition metal oxide include titanium oxide and vanadium oxide. , tantalum oxide, molybdenum oxide, tungsten oxide, rhenium oxide, ruthenium oxide, chromium oxide, zirconium oxide, hafnium oxide, silver oxide, etc. Among them, molybdenum oxide is particularly preferable because it is stable in the air, has low hygroscopicity, and is inexpensive. By using the transition metal oxide, the electron injection barrier with the electrode 102 can be reduced, which is preferable. Therefore, one aspect of the present invention is a light-emitting device in which the electron injection layer 130 contains a transition metal element and the charge generation layer 160 contains a transition metal element. Note that the electron-accepting material contained in the charge generation layer 160 is not limited to the above-described compounds. 0 is not limited to the above-described compounds.

[0104] In addition, as the hole-transporting material contained in the charge generation layer 160, it is preferable to use an organic compound containing any one of a pyrrole skeleton, a thiophene skeleton, a furan skeleton, or an aromatic amine skeleton. Since the organic compound having such a skeleton has high hole-transporting properties, the driving voltage of the light-emitting device can be reduced by using it in the charge generation layer 160. The hole-transporting material contained in the charge generation layer 160 is not limited to the above-described compounds.

[0105] <Configuration Example 4 of Light-Emitting Device> Next, a configuration example different from the light-emitting device 150 shown in FIG. 1, the light-emitting device 152 shown in FIG. 2, and the light-emitting device 154 will be described below with reference to FIG. 49.

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

[0107] The light-emitting devices 2250a and 2250b have an electrode 2101, an electrode 2 102, an electrode 2103, and an electrode 2104 on a substrate 2200. Further, between the electrode 2101 and the electrode 2 Between 102, between electrode 2102 and electrode 2103, and between electrode 2102 and electrode 210 4, at least the light emitting unit 2106 and the light emitting unit 2108 and the electron injection layer 2 130. Also, a charge generation layer 2115 is provided between the light emitting unit 2106 and the light emitting unit 2108. Note that the light emitting unit 2106 and the light emitting unit 2108 may have the same configuration or different configurations.

[0108] The charge generation layer 2115 sandwiched between the light emitting unit 2106 and the light emitting unit 2108, for example when a voltage is applied between electrode 2101 and electrode 2102, as long as it injects electrons into one light emitting unit and injects holes into the other light emitting unit. For example, in FIG. 49 when a voltage is applied so that the potential of electrode 2102 is higher than the potential of electrode 2101 the charge generation layer 2115 injects electrons into the light emitting unit 2106 and injects holes into the light emitting unit 2 108.

[0109] Also, the light emitting unit 2106 has, for example, a hole injection layer 2111, a hole transport layer 2112, a light emitting layer 2140, and an electron transport layer 2113. Also, the light emitting unit 2108 has, for example a hole injection layer 2116, a hole transport layer 2117, a light emitting layer 2170, and an electron transport layer 21 18, and an electron injection layer 2119.

[0110] Here, as shown in FIG. 49, the electron injection layer 2130 is adjacent to the electron transport layer 2113 and is preferably provided between the light emitting unit 2108 and the electron transport layer 2113. Also, the charge generation layer 2115 is adjacent to the electron injection layer 2130 and is preferably provided between the electron injection layer 2130 and the light emitting unit 2108. By adopting such a configuration, the light emitting unit 2 Electrons can be efficiently transported to 106.

[0111] In the configuration example of the light-emitting element, electrodes 2101, 2103, and 2104 are described as the anode, and electrode 2102 is described as the cathode. However, the configurations of light-emitting elements 2250a and 2 250b are not limited to this. That is, electrodes 2101, 2103, and 2104 can be used as the cathode, electrode 2102 can be used as the anode, and the stacking order of each layer between the electrodes can be reversed. That is, the light-emitting unit 2106 may have the stacking order of, from the anode side, a hole injection layer 211 1, a hole transport layer 2112, a light-emitting layer 2140, an electron transport layer 2113, and an electron injection layer 2 130. The light-emitting unit 2108 may have the stacking order of, from the anode side, a hole injection layer 2116, a hole transport layer 2117, a light-emitting layer 2170, an electron transport layer 2118, and an electron injection layer 2119.

[0112] Also, the configurations of light-emitting elements 2250a and 2250b are not limited to the configuration shown in FIG. 49. At least a light-emitting layer 2140, a light-emitting layer 2170, a charge generation layer 2115, and an electron injection layer 2130 are included, and a hole injection layer 2111, a hole injection layer 2116, a hole transport layer 21 12, a hole transport layer 2117, an electron transport layer 2113, an electron transport layer 2118, and an electron injection layer 21 19 may or may not be included.

[0113] Also, a layer corresponding to the function may be formed between the pair of electrodes, but it is not limited to this. That is, between the pair of electrodes, a layer that reduces the injection barrier of holes or electrons, improves the transportability of holes or electrons, inhibits the transportability of holes or electrons, or suppresses the quenching phenomenon caused by the electrodes may be provided. It may be configured to have a layer having functions such as being able to control, etc.

[0114] In addition, when the anode side surface of the light emitting unit is in contact with the charge generation layer 2115 as in the light emitting unit 2108, the charge generation layer 2115 may also serve as the hole injection layer of the light emitting unit 2108, so it may not be necessary to provide a hole injection layer in the light emitting unit. In addition, when the anode side surface of the light emitting unit is in contact with the charge generation layer 2115 as in the light emitting unit 2108, the charge generation layer 2115 may also serve as the hole injection layer of the light emitting unit 2108, so it may not be necessary to provide a hole injection layer in the light emitting unit. In addition, when the anode side surface of the light emitting unit is in contact with the charge generation layer 2115 as in the light emitting unit 2108, the charge generation layer 2115 may also serve as the hole injection layer of the light emitting unit 2108, so it may not be necessary to provide a hole injection layer in the light emitting unit. There are cases.

[0115] Also, in FIG. 49, a light emitting element having two light emitting units was described, but the same can be applied to a light emitting element in which three or more light emitting units are stacked. As shown in the light emitting element 2250a and the light emitting element 2250b, by arranging a plurality of light emitting units between a pair of electrodes separated by a charge generation layer, high-brightness light emission can be achieved while keeping the current density low, and a longer-life light emitting element can be realized. Also, a light emitting element with low power consumption can be realized. Also, in FIG. 49, a light emitting element having two light emitting units was described, but the same can be applied to a light emitting element in which three or more light emitting units are stacked. As shown in the light emitting element 2250a and the light emitting element 2250b, by arranging a plurality of light emitting units between a pair of electrodes separated by a charge generation layer, high-brightness light emission can be achieved while keeping the current density low, and a longer-life light emitting element can be realized. Also, a light emitting element with low power consumption can be realized. Also, in FIG. 49, a light emitting element having two light emitting units was described, but the same can be applied to a light emitting element in which three or more light emitting units are stacked. As shown in the light emitting element 2250a and the light emitting element 2250b, by arranging a plurality of light emitting units between a pair of electrodes separated by a charge generation layer, high-brightness light emission can be achieved while keeping the current density low, and a longer-life light emitting element can be realized. Also, a light emitting element with low power consumption can be realized. Also, in FIG. 49, a light emitting element having two light emitting units was described, but the same can be applied to a light emitting element in which three or more light emitting units are stacked. As shown in the light emitting element 2250a and the light emitting element 2250b, by arranging a plurality of light emitting units between a pair of electrodes separated by a charge generation layer, high-brightness light emission can be achieved while keeping the current density low, and a longer-life light emitting element can be realized. Also, a light emitting element with low power consumption can be realized. Also, in FIG. 49, a light emitting element having two light emitting units was described, but the same can be applied to a light emitting element in which three or more light emitting units are stacked. As shown in the light emitting element 2250a and the light emitting element 2250b, by arranging a plurality of light emitting units between a pair of electrodes separated by a charge generation layer, high-brightness light emission can be achieved while keeping the current density low, and a longer-life light emitting element can be realized. Also, a light emitting element with low power consumption can be realized. There are cases.

[0116] In the light emitting element 2250a, the electrodes 2101, 2103, and 2104 have a function of reflecting visible light, and the electrode 2102 has a function of transmitting visible light. Also, in the light emitting element 2250b, the electrodes 2101, 2103, and 2104 have a function of transmitting visible light, and the electrode 2102 has a function of reflecting visible light. In the light emitting element 2250a, the electrodes 2101, 2103, and 2104 have a function of reflecting visible light, and the electrode 2102 has a function of transmitting visible light. Also, in the light emitting element 2250b, the electrodes 2101, 2103, and 2104 have a function of transmitting visible light, and the electrode 2102 has a function of reflecting visible light. In the light emitting element 2250a, the electrodes 2101, 2103, and 2104 have a function of reflecting visible light, and the electrode 2102 has a function of transmitting visible light. Also, in the light emitting element 2250b, the electrodes 2101, 2103, and 2104 have a function of transmitting visible light, and the electrode 2102 has a function of reflecting visible light. In the light emitting element 2250a, the electrodes 2101, 2103, and 2104 have a function of reflecting visible light, and the electrode 2102 has a function of transmitting visible light. Also, in the light emitting element 2250b, the electrodes 2101, 2103, and 2104 have a function of transmitting visible light, and the electrode 2102 has a function of reflecting visible light.

[0117] Therefore, the light emitted by the light emitting element 2250a is emitted to the outside through the electrode 2102, and the light emitted by the light emitting element 2250b is emitted to the outside through the electrodes 2101, 2103, and 2104. However, one aspect of the present invention is not limited to this, and the light emitting element is formed Therefore, the light emitted by the light emitting element 2250a is emitted to the outside through the electrode 2102, and the light emitted by the light emitting element 2250b is emitted to the outside through the electrodes 2101, 2103, and 2104. However, one aspect of the present invention is not limited to this, and the light emitting element is formed Therefore, the light emitted by the light emitting element 2250a is emitted to the outside through the electrode 2102, and the light emitted by the light emitting element 2250b is emitted to the outside through the electrodes 2101, 2103, and 2104. However, one aspect of the present invention is not limited to this, and the light emitting element is formed It may be a light-emitting element that extracts light both above and below the substrate 2200 to be obtained.

[0118] Further, the electrode 2101 has a conductive layer 2101a and a conductive layer 21 01b that is in contact with the conductive layer 2101a. Further, the electrode 2103 has a conductive layer 2103a and a conductive layer 2103a and a conductive layer 2103b that is in contact therewith. The electrode 2104 has a conductive layer 2104a and a conductive layer 2104b that is in contact with the conductive layer 2104a.

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

[0120] The light-emitting element 2250a shown in FIG. 49(A) and the light-emitting element 2250b shown in FIG. 49(B) have a partition wall 2145 between a region 2222B sandwiched between the electrode 2101 and the electrode 2102, a region 2222G sandwiched between the electrode 2102 and the electrode 2 103, and a region 2222R sandwiched between the electrode 2102 and the electrode 2104. The partition wall 2145 has insulating properties. The partition wall 2145 covers the ends of the electrode 2101, the electrode 2103, and the electrode 2104 and has an opening that overlaps with the electrodes. By providing the partition wall 2145, the electrodes on the substrate 2200 in each region can be separated into island shapes respectively. can be separated into island shapes respectively.

[0121] Note that in FIG. 49, the hole injection layer 2111, the hole injection layer 2116, the hole transport layer 21 ​12. The hole transport layer 2117, the light-emitting layer 2140, the light-emitting layer 2170, the electron transport layer 2113, the electron transport layer 2118, the electron injection layer 2119, the charge generation layer 2115, and the electrode 2102 are illustrated in a state where they are provided in common without being separated in each region, but they may be provided separately in each region.

[0122] In the light-emitting elements 2250a and 2250b according to one aspect of the present invention, between a pair of electrodes (electrode 2101 and electrode 2102) in the region 2222B, between a pair of electrodes (electrode 2102 and electrode 2103) in the region 2222G, and between a pair of electrodes (electrode 2102 and electrode 2104) in the region 2222R, by applying a voltage, electrons are injected from the cathode into the electron injection layer 2119, and holes are injected from the anode into the hole injection layer 2111, thereby causing a current to flow. Also, electrons are injected from the charge generation layer 2115 into the electron injection layer 2130, and holes (holes) are injected from the charge generation layer 2115 into the hole injection layer 2116. Then, the injected carriers (electrons and holes) recombine to form excitons. In the light-emitting layers 2140 and 2170 having a light-emitting material, when carriers (electrons and holes) recombine to form excitons, the light-emitting materials included in the light-emitting layers 2140 and 2170 are excited, and light is obtained from the light-emitting material.

[0123] The light-emitting layers 2140 and 2170 preferably have any one or more of light-emitting materials that emit light of purple, blue, cyan, green, yellow-green, yellow, orange, or red.

[0124] Also, the light-emitting layers 2140 and 2170 may have a structure in which two layers are stacked. In the light-emitting layer of the layer, by using two types of light-emitting materials, namely a first compound and a second compound, each having a function of exhibiting a different color, a plurality of emissions can be obtained simultaneously. In particular, it is preferable to select the light-emitting materials used for each light-emitting layer so that the emissions exhibited by the light-emitting layer 2140 and the light-emitting layer 2170 become white or a color close thereto. Also, the light-emitting layer 2140 and the light-emitting layer 2170 may have a structure in which three or more layers are stacked, and may include a layer having no light-emitting material.

[0125] Further, the light-emitting element 2250a and the light-emitting element 2250b each have a substrate 2220 having optical elements 2224B, optical elements 2224G, and optical elements 2224R in the direction in which the light emitted from the region 2222B, the region 2222G, and the region 2222R is extracted. The light emitted from each region is emitted to the outside of the light-emitting element through each optical element. That is, the light emitted from the region 2222B is emitted through the optical element 2224B, the light emitted from the region 2222G is emitted through the optical element 2224G, and the light emitted from the region 2222R is emitted through the optical element 2224R.

[0126]

[0127] Also, the optical element 2224B, the optical element 2224G, and the optical element 2224R have a function of selectively transmitting light exhibiting a specific color from the incident light. For example, the light emitted from the region 2222B and emitted through the optical element 2224B becomes light exhibiting blue, the light emitted from the region 2222G and emitted through the optical element 2224G becomes light exhibiting green, and the light emitted from the region 2222R and emitted through the optical element 2224R becomes light exhibiting red. ​​​​​​​​​​​​​​​

[0128] In FIGS. 49(A) and (B), the light emitted from each region through each optical element is represented as light presenting blue (B), light presenting green (G), and light presenting red (R), respectively, and is schematically illustrated by dashed arrows. The light-emitting element 2250a shown in FIG. 49(A) is a top emission type light-emitting element, and the light-emitting element 2250b shown in FIG. 49(B) is a bottom emission type light-emitting element.

[0129] Further, a light-shielding layer 2223 is provided between the optical elements. The light-shielding layer 2223 has a function of shielding the light emitted from adjacent regions. Note that a configuration without providing the light-shielding layer 2223 may be adopted. Also, a configuration in which any one or two or more of the optical elements 2224B, 2224G, or 2224R are not provided may be adopted. By adopting a configuration in which the optical elements 2224B, 2224G, or 2224R are not provided, the extraction efficiency of the light emitted from the light-emitting element can be increased.

[0130] Also, as the charge generation layer 2115, it can be formed by a material in which an electron acceptor is added to a hole transporting material, or a material in which an electron donor is added to an electron transporting material.

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

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

[0133] The crosstalk occurs when the electron injection layer 2115 and the electron transport layer 2113 are sandwiched between the electron generation layer 2115 and the electron transport layer 2113. The alkali metal, alkaline earth metal, or compound thereof used in 130 is an electron transport layer 2 The conductivity of the electron transport layer 2113 (especially the conductivity in the direction perpendicular to the voltage application direction) is increased. One of the reasons for this is that the electrical conductivity of the material is improved. When these compounds are used in the electron injection layer 2130, the metal with a small atomic number is likely to diffuse into the electron transport layer 2113. Therefore, in order to suppress crosstalk, it is preferable that the electron injection layer 2130 does not contain alkali metals and alkaline earth metals. On the other hand, when the electron injection layer 2130 does not use alkali metals, alkaline earth metals, or their compounds, the electron injection barrier from the charge generation layer 2115 to the electron transport layer 2113 becomes high, making it difficult for electrons to be injected into the electron transport layer 2113, and the driving voltage of the light-emitting device may increase or the luminous efficiency may decrease. Therefore, in order to reduce the driving voltage of the light-emitting device, improve the luminous efficiency, and suppress crosstalk, it is preferable to use a metal with excellent electron injection properties and low diffusibility in the electron injection layer 2130. As the metal with low diffusibility used in the electron injection layer 2130, a metal with a large atomic radius is preferable. Also, a metal with a large atomic weight is preferable. On the other hand, although metals with a large atomic radius and metals with a large atomic weight are difficult to diffuse, when used in the electron injection layer 2130, an electron injection barrier may be formed between the charge generation layer 2115 and the electron transport layer 2113, and the driving voltage of the light-emitting device may increase or the luminous efficiency may decrease. Here, the inventors have found that by using a composite material of a compound of the above-mentioned combination forming SOMO and a transition metal in the electron injection layer 2130 adjacent to the charge generation layer 2115, a light-emitting device with good electron injection characteristics and suppressed crosstalk can be obtained. Therefore, a light-emitting device according to one aspect of the present invention is a light-emitting device having a plurality of light-emitting units, and in the light-emitting device having a plurality of light-emitting units, a non- - -

[0134] - - - -

[0135] - - -

[0136] - - -

[0137] - An organic compound having a shared electron pair and a composite material of a transition metal are provided between light-emitting units for an electron injection layer 2130 used in a light-emitting element.

[0138] Since the transition metal has a large atomic weight and is difficult to diffuse in the organic compound, crosstalk is suppressed, and a light-emitting element can be provided.

[0139] Note that the organic compound having the above unshared electron pair is responsible for electron transport, and thus preferably has at least a π-conjugated system. In this case, an atom having π electrons (Pz orbitals) preferably has the unshared electron pair, or an atom bonded to (adjacent to) an atom having π electrons (Pz orbitals) preferably has the unshared electron pair.

[0140] Here, when the composite material of the transition metal 132 and the compound 131 shown in FIG. 1 is used for the electron injection layer 2130, the HOMO level formed by the interaction between the atoms of the compound 131 and the transition metal 132 is preferably the same as the HOMO level of the original compound 131. When an organic compound having a function of transporting electrons is used as the compound 131, the HOMO level of the compound 131 is low and holes are difficult to be injected into the compound 131. Therefore, when the HOMO level formed by the interaction between the compound 131 and the transition metal 132 is the same as the HOMO level of the original compound 131, the hole injection barrier between the electron injection layer 2130 and the charge generation layer 2115 becomes large, so that holes are difficult to escape from the electron injection layer 2130 to the charge generation layer 2115, and the carrier balance in the light-emitting element can be improved, which is preferable. 2, and the HOMO level formed by the interaction between the compound 131 and the transition metal 132 is the same as the HOMO level of the original compound 131, the hole injection barrier between the electron injection layer 2130 and the charge generation layer 2115 becomes large, so that holes are difficult to escape from the electron injection layer 2130 to the charge generation layer 2115, and the carrier balance in the light-emitting element can be improved, which is preferable. For this reason, it is preferable because the carrier balance in the light-emitting element can be improved.

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

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

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

[0144] ≪Electron injection layer≫ The electron injection layers 130, 2130, and 2119 are layers containing a material with high electron injection properties, and a composite material of the above-described transition metal and an organic compound having a non-bonding electron pair can be preferably used. Further, as the organic compound used for the electron injection layers 130, 2130, and 2119, a material having excellent electron transport properties is preferable. Specifically, for example, metal complexes, heteroaromatic compounds, etc. listed below can be used. The electron injection layers 130, 2130, and 2119 include metal complexes having a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand, pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, triazine derivatives, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, and the like. Specifically, metal complexes such as Alq3, Almq3, BeBq2, BAlq, bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ) can be used. Also, 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole The electron injection layers 130, 2130, and 2119 are layers containing a material with high electron injection properties, and a composite material of the above-described transition metal and an organic compound having a non-bonding electron pair can be preferably used. Further, as the organic compound used for the electron injection layers 130, 2130, and 2119, a material having excellent electron transport properties is preferable. Specifically, for example, metal complexes, heteroaromatic compounds, etc. listed below can be used. The electron injection layers 130, 2130, and 2119 include metal complexes having a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand, pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, triazine derivatives, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, and the like. Specifically, metal complexes such as Alq3, Almq3, BeBq2, BAlq, bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ) can be used. Also, 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole The electron injection layers 130, 2130, and 2119 include metal complexes having a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand, pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, triazine derivatives, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, and the like. Specifically, metal complexes such as Alq3, Almq3, BeBq2, BAlq, bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ) can be used. Also, 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole

[0145] The electron injection layers 130, 2130, and 2119 include metal complexes having a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand, pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, triazine derivatives, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, and the like. The electron injection layers 130, 2130, and 2119 include metal complexes having a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand, pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, triazine derivatives, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, and the like. The electron injection layers 130, 2130, and 2119 include metal complexes having a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand, pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, triazine derivatives, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, and the like. The electron injection layers 130, 2130, and 2119 include metal complexes having a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand, pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, triazine derivatives, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, and the like. Specifically, metal complexes such as Alq3, Almq3, BeBq2, BAlq, bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ) can be used. Also, 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole The electron injection layers 130, 2130, and 2119 include metal complexes having a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand, pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, triazine derivatives, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, and the like. Specifically, metal complexes such as Alq3, Almq3, BeBq2, BAlq, bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ) can be used. Also, 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole The electron injection layers 130, 2130, and 2119 include metal complexes having a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand, pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, triazine derivatives, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, and the like. Specifically, metal complexes such as Alq3, Almq3, BeBq2, BAlq, bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ) can be used. Also, 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole The electron injection layers 130, 2130, and 2119 include metal complexes having a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand, pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, triazine derivatives, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, and the like. Specifically, metal complexes such as Alq3, Almq3, BeBq2, BAlq, bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ) can be used. Also, 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole The electron injection layers 130, 2130, and 2119 include metal complexes having a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand, pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, triazine derivatives, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, and the like. Specifically, metal complexes such as Alq3, Almq3, BeBq2, BAlq, bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ) can be used. Also, 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole The electron injection layers 130, 2130, and 2119 include metal complexes having a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand, pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, triazine derivatives, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, and the like. Specifically, metal complexes such as Alq3, Almq3, BeBq2, BAlq, bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ) can be used. Also, 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole PBD, 1,3-bis[5-(p-tert-butylphenyl)-1,3, 4-Oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-furan phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole ( Abbreviation: CO11), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-bu 3-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 4-(4-ethylphenyl)-5-(4-biphenylyl)-1,2,4 -Triazole (abbreviation: p-EtTAZ), 4,4'-bis(5-methylbenzoxazo 2,2',2''-(1,3,5-phenyl-2-yl)stilbene (abbreviation: BzOs), 1-phenyl-1H-benzimidazole (TPBI) ), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzyl Heterocyclization of azole skeleton such as benzimidazole (abbreviation: mDBTBIm-II) Compounds such as 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]ky Noxalin (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophene- 4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBT BPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3- yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3 ,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quino Xaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophene-4-yl) 7mDBTPDBq-II and 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzof[h]quin oxaline (abbreviation: 6mDBTPDBq-II), 4,6-bis[3-(phenanthren- 9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3- (4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II ), 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation : 4,6mCzP2Pm), 4-{3-[3’-(9H-carbazol-9-yl)]bi phenyl-3-yl}benzofuro[3,2-d]pyrimidine (abbreviation: 4mCzBPBfp m) and other heterocyclic compounds having a diazine skeleton, 2-{4-[3-(N-phenyl-9 H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6- diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2,4,6-tris [3’-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbre viation: TmPPPyTz), 2,4,6-tris(2-pyridyl)-1,3,5-triazi ne (abbreviation: 2Py3Tzn) and other heterocyclic compounds having a triazine skeleton, 3,5-bis [3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPP y), 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyP B), bathocuproine (abbreviation: BCP), 2,9-bis(naphthalen-2-yl)-4 ,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen) and other heterocyclic compounds having a pyridine skeleton are exemplified. Among those described above, the diazine skeleton and the triazine Heterocyclic compounds having a skeleton or heterocyclic compounds having a pyridine skeleton have good reliability and are preferable. In particular, heterocyclic compounds having a diazine (pyrimidine or pyrazine) skeleton and a triazine skeleton have high electron transport properties and contribute to reducing the driving voltage. The substances described here are mainly substances having an electron mobility of 1×10 -6 cm 2 / Vs or more. Note that, as long as the substance has higher electron transport properties than holes, substances other than the above may be used for the electron injection layer 130, the electron injection layer 213 0 and the electron injection layer 2119.

[0146] ≪Hole injection layer≫ The hole injection layer 111 and the hole injection layer 2111 promote hole injection from one of a pair of electrodes (electrode 101 or electrode 102, electrode 2101 or electrode 2102). The hole injection layer 2116 has a function of promoting hole injection by reducing the hole injection barrier from the charge generation layer 2115, and is formed by, for example, transition metal oxides, phthalocyanine derivatives, or aromatic amines. Examples of the transition metal oxides include molybdenum oxides, vanadium oxides, ruthenium oxides, tungsten oxides, and manganese oxides. Examples of the phthalocyanine derivatives include phthalocyanine and metal phthalocyanine. Examples of the aromatic amines include benzidine derivatives and phenylenediamine derivatives. High molecular compounds such as polythiophene and polyaniline can also be used. For example, poly(ethylenedioxythiophene) / poly(styrenesulfonic acid) which is a self-doped polythiophene is a typical example.

[0147] As the hole injection layer 111, the hole injection layer 2111, and the hole injection layer 2116, hole transport materials A layer having a composite material of a material and a material exhibiting electron accepting properties can also be used. Alternatively, a laminate of a layer containing a material exhibiting electron accepting properties and a layer containing a hole transporting material may be used. Charge transfer is possible between these materials in a steady state or in the presence of an electric field. Examples of the material exhibiting electron accepting properties include organic acceptors such as quinodimethane derivatives, chloranil derivatives, and hexaazatriphenylene derivatives. Specifically, 7, 7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4 -TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5, 8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), etc., are compounds having an electron withdrawing group (halogen group or cyano group). Further, transition metal oxides, for example, oxides of metals from Group 4 to Group 8 can be used. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, rhenium oxide, etc. Among them, molybdenum oxide is stable in the air, has low hygroscopicity, and is easy to handle. Therefore, it is preferable.

[0148] As the hole transporting material, a material having higher hole transporting property than electrons can be used, and it is preferably a material having a hole mobility of 1 × 10 cm -6 / Vs or more. Specifically, aromatic amines, carbazole derivatives, aromatic hydrocarbons, stilbene derivatives, etc., which can be used as the hole transporting material for the light emitting layer 140, can be used. Further, 2 the hole transporting material may be a polymer compound.

[0149] ​​​​​​​In addition, other hole transporting materials include aromatic hydrocarbons, for example, 2-tert -butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 2- tert-butyl-9,10-di(1-naphthyl)anthracene, 9,10-bis(3, 5-diphenylphenyl)anthracene (abbreviation: DPPA), 2-tert-butyl-9 ,10-bis(4-phenylphenyl)anthracene (abbreviation: t-BuDBA), 9,1 0-di(2-naphthyl)anthracene (abbreviation: DNA), 9,10-diphenylanthra cene (abbreviation: DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAn th), 9,10-bis(4-methyl-1-naphthyl)anthracene (abbreviation: DMNA) , 2-tert-butyl-9,10-bis[2-(1-naphthyl)phenyl]anthracene ene, 9,10-bis[2-(1-naphthyl)phenyl]anthracene, 2,3,6,7- tetramethyl-9,10-di(1-naphthyl)anthracene, 2,3,6,7-tetram hyl-9,10-di(2-naphthyl)anthracene, 9,9'-bianthryl, 10,1 0'-diphenyl-9,9'-bianthryl, 10,10'-bis(2-phenylphenyl yl)-9,9'-bianthryl, 10,10'-bis[(2,3,4,5,6-pentaflu enyl)phenyl]-9,9'-bianthryl, anthracene, tetracene, rubrene, perylene, 2,5,8,11-tetra(tert-butyl)perylene, etc. are mentioned. Fur thermore, pentacene, coronene, etc. can also be used. Thus, it is more preferable to use an aromatic hydrocarbon having a hole mobility of 1×10 -6 cm 2 / Vs or more and having 14 to 42 carbon atoms. ​

[0150] In addition, the aromatic hydrocarbon may have a vinyl skeleton. Examples of the aromatic hydrocarbon having a vinyl group include 4,4'-bis(2,2-diphenylvinyl)biphenyl (abbreviation: DPVBi), 9,10-bis[4-(2,2-diphenylvinyl)phenyl]anthracene (abbreviation: DPVPA), and the like.

[0151] Also, 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), 1,3,5-tri(dibenzothiophen-4-yl)benzene (abbreviation: DBT3P-II ), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl -9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation : DBTFLP-IV), 4-[3-(triphenylene-2-yl)phenyl]dibenzothiophene (abbreviation : mDBTPTp-II), and other thiophene compounds, furan compounds, fluorene compounds, triphenylene compounds, phenanthrene compounds, etc. can be used. Among the above-described compounds, compounds having a pyrrole skeleton, a furan skeleton, a thiophene skeleton, or an aromatic amine skeleton are preferable because they are stable and have good reliability. Further, the compounds having such a skeleton have high hole transportability and contribute to reducing the driving voltage.

[0152] <<Hole transport layer>> The hole transport layers 112, 2112, and 2117 contain hole transporting materials and are layers that can use the materials exemplified as the materials for the hole injection layers 111, 2111, and 2116. The hole transport layers 112, 2112, and 2117 each have the function of transporting the holes injected from the hole injection layers 111, 2111, and 2116 to the light emitting layers 140, 2140, and 2170, respectively. At this time, it is preferable to use a hole transporting material having a HOMO level between the LUMO level of the acceptor material of the hole injection layer 111 and the HOMO level of the material of the light emitting layer 140 for the hole transport layer 112. Similarly, it is preferable to use a hole transporting material having a HOMO level between the LUMO level of the acceptor material of the hole injection layer 2111 and the HOMO level of the material of the light emitting layer 2140 for the hole transport layer 2112. Further, the hole transport layers 112, 2112, and 2117 may be not only single layers but also laminated with two or more layers. In this case, it is preferable to laminate the hole transporting materials so that the HOMO levels decrease in order from the side of the hole injection layer 111 to the side of the light emitting layer 140, from the side of the hole injection layer 2111 to the side of the light emitting layer 2140, and from the side of the hole injection layer 2116 to the side of the light emitting layer 2170. When the hole transport layers 112, 2112, and 2117 are laminated with two or more layers, in order to transport holes smoothly, the difference in the HOMO levels of the hole transporting materials used is preferably 0 eV or more and 0.5 eV or less, more preferably 0 eV or more and 0.3 eV or less, and still more preferably 0 eV or more and 0.2 eV or less.

[0153]

[0154] ​​​​​​​​​​​​​​​​Examples of materials having hole transporting properties include, for example, 4,4'-bis[N-(1-naphthyl)- N-phenylamino]biphenyl (abbreviation: NPB), N,N'-bis(3-methylphenyl yl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4'-bis[N-(spiro-9,9'-bifluorene-2-yl)-N- phenylamino]biphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenyl fluorene-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3 '-(9-phenylfluorene-9-yl)triphenylamine (abbreviation: mBPAFLP ), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenyl lamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl- 9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4- (1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenyl lamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phe nyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), 9 ,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3- yl)phenyl]fluorene-2-amine (abbreviation: PCBAF), N-phenyl-N- 4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9'-bi fluorene-2-amine (abbreviation: PCBASF), etc., compounds having an aromatic amine skeleton and 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N- carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl 9-phenylcarbazole (abbreviation: CzTP), 3,3'-bis(9-phenyl- 9H-carbazole) (abbreviation: PCCP), and other compounds having a carbazole skeleton, 4 ,4',4''-(benzene-1,3,5-triyl)tris(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-phenyldibenzothiophene (abbreviation: DBTFLP-IV), and other compounds having a thiophene skeleton, 4,4',4''-(benzene-1,3,5-triyl)tris(dibenzofuran) (abbreviation: DBF3P-II), 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), and other compounds having a furan skeleton. Among the above-mentioned compounds, compounds having an aromatic amine skeleton or a carbazole skeleton are preferable because they have good reliability, high hole transportability, and contribute to reducing the driving voltage. In addition to the hole transport materials described above, hole transport materials may be used from various substances. 4,4',4''-(benzene-1,3,5-triyl)tris(dibenzofuran) (abbreviation: DBF3P-II), 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), and other compounds having a furan skeleton. Among the above-mentioned compounds, compounds having an aromatic amine skeleton or a carbazole skeleton are preferable because they have good reliability, high hole transportability, and contribute to reducing the driving voltage. In addition to the hole transport materials described above, hole transport materials may be used from various substances. )phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), and other compounds having a furan skeleton are exemplified. Among the above, compounds having an aromatic amine skeleton or a carbazole skeleton are preferable because they have good reliability, high hole transportability, and contribute to reducing the driving voltage. Also, in addition to the hole transport materials described above, hole transport materials may be used from various substances. Among the above, compounds having an aromatic amine skeleton or a carbazole skeleton are preferable because they have good reliability, high hole transportability, and contribute to reducing the driving voltage. Also, in addition to the hole transport materials described above, hole transport materials may be used from various substances. Among the above, compounds having an aromatic amine skeleton or a carbazole skeleton are preferable because they have good reliability, high hole transportability, and contribute to reducing the driving voltage. Also, in addition to the hole transport materials described above, hole transport materials may be used from various substances. Among the above, compounds having an aromatic amine skeleton or a carbazole skeleton are preferable because they have good reliability, high hole transportability, and contribute to reducing the driving voltage. Also, in addition to the hole transport materials described above, hole transport materials may be used from various substances. Among the above, compounds having an aromatic amine skeleton or a carbazole skeleton are preferable because they have good reliability, high hole transportability, and contribute to reducing the driving voltage. Also, in addition to the hole transport materials described above, hole transport materials may be used from various substances.

[0155] Furthermore, as substances with high hole transportability, for example, 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 3-[4-(9-phenanthryl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPPn), 4 -phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine -phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine -phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine ン(abbreviation: PCBA1BP), 4,4'-di(1-naphthyl)-4''-(9-phenyl -9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), 4-f enyl diphenyl-(9-phenyl-9H-carbazol-3-yl)amine (abbreviation: P CA1BP), 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP ), N-[4-(9H-carbazol-9-yl)phenyl]-N-(4-phenyl)f enylaniline (abbreviation: YGA1BP), 1,3,5-tri(dibenzothiophen-4- yl)-benzene (abbreviation: DBT3P-II), 4,4',4''-(benzene-1,3 ,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), 4-phenyl- 4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP ), 4-[3-(triphenylene-2-yl)phenyl]dibenzothiophene (abbreviation: m DBTPTp-II), 4,4'-bis[N-(1-naphthyl)-N-phenylamino] biphenyl (abbreviation: NPB or α-NPD), N,N'-bis(3-methylphenyl) -N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TP D), 4,4',4''-tris(carbazol-9-yl)triphenylamine (abbreviation : TCTA), 4,4',4''-tris(N,N-diphenylamino)triphenyl a mine (abbreviation: TDATA), 4,4',4''-tris[N-(3-methylphenyl)- N-phenylamino]triphenylamine (abbreviation: MTDATA), 4,4'-bis[N -(spiro-9,9'-bifluorene-2-yl)-N-phenylamino]biphenyl ([[]] abbreviation: BSPB), etc. compounds having an aromatic amine skeleton, 3-[N-(9-phenylka (3 - carbazolyl)-N - phenylamino]-9 - phenylcarbazole (abbreviation: P CzPCA1), 3,6 - bis[N-(9 - phenylcarbazol - 3 - yl)-N - f enylamino]-9 - phenylcarbazole (abbreviation: PCzPCA2), 3 - [N-(1 - naphthyl)-N-(9 - phenylcarbazol - 3 - yl)amino]-9 - phenylcarb azole (abbreviation: PCzPCN1), etc. Other examples include 4,4’ - di(N - carb azolyl)biphenyl (abbreviation: CBP), 1,3,5 - tris[4-(N - carbazolyl )phenyl]benzene (abbreviation: TCPB), etc. carbazole compounds, amine compounds, dib enzothiophene compounds, dibenzofuran compounds, fluorene compounds, triphenylene compounds , phenanthrene compounds, etc. can be used. The substances listed here mainly have a hole mobility of 1×10 -6 cm 2 / Vs or more. However, as long as the substance has higher hole - transporting properties than electrons, other substances may also be used.

[0156] In addition, the compounds that can be used as the hole - transport layer can also be used as the hole - injection layer.

[0157] <<Charge - generating layer>> The charge - generating layer 160 and the charge - generating layer 2115 can be configured such that an acceptor substance, which is an electron acceptor, is added to a hole - transporting material, or a donor substance, which is an electron donor, is added to an electron - transporting material. Also, a structure in which both of these configurations are laminated may be used.

[0158] In the charge - generating layer 160 and the charge - generating layer 2115, a composite of an organic compound and an acceptor substance When a material is included, a composite material that can be used for the hole injection layer 111 described above may be used for the composite material. As the organic compound, various compounds such as aromatic amine compounds, carbazole compounds, aromatic hydrocarbons, and polymer compounds (oligomers, dendrimers, polymers, etc.) can be used. Note that, as the organic compound, it is preferable to apply a substance having a hole mobility of 1×10 -6 c m 2 / Vs or more. However, as long as the substance has higher hole transportability than electrons, substances other than these may be used. The composite material of the organic compound and the acceptor substance is excellent in carrier injection property and carrier transport property, so that low voltage driving and low current driving can be realized. When the surface on the anode side of the light emitting unit is in contact with the charge generation layer 160 and the charge generation layer 2115, since the charge generation layer 160 and the charge generation layer 2115 can also serve as the hole injection layer or the hole transport layer of the light emitting unit, the light emitting unit may be configured without providing a hole injection layer or a hole transport layer. Note that, when the surface on the anode side of the light emitting unit is in contact with the charge generation layer 160 and the charge generation layer 2115, the charge generation layer 160 and the charge generation layer 2115 can also serve as the hole injection layer or the hole transport layer of the light emitting unit, so that the light emitting unit may be configured without providing a hole injection layer or a hole transport layer. Note that the charge generation layer 160 and the charge generation layer 2115 may be formed as a laminated structure in which a layer containing a composite material of an organic compound and an acceptor substance and a layer composed of other materials are combined.

[0159] Note that the charge generation layer 160 and the charge generation layer 2115 may be formed as a laminated structure in which a layer containing a composite material of an organic compound and an acceptor substance and a layer composed of other materials are combined. For example, it may be formed by combining a layer containing a composite material of an organic compound and an acceptor substance with a layer containing one compound selected from electron donating substances and a compound having high electron transportability. Alternatively, it may be formed by combining a layer containing a composite material of an organic compound and an acceptor substance with a layer containing a transparent conductive film. Note that, from the viewpoint of light extraction efficiency, the charge generation layer 160 and the charge generation layer 2115 are visible light For example, it may be formed by combining a layer containing a composite material of an organic compound and an acceptor substance with a layer containing one compound selected from electron donating substances and a compound having high electron transportability. Also, it may be formed by combining a layer containing a composite material of an organic compound and an acceptor substance with a layer containing a transparent conductive film. Note that the charge generation layer 160 and the charge generation layer 2115 may be formed as a laminated structure in which a layer containing a composite material of an organic compound and an acceptor substance and a layer composed of other materials are combined. For example, it may be formed by combining a layer containing a composite material of an organic compound and an acceptor substance with a layer containing one compound selected from electron donating substances and a compound having high electron transportability. Also, it may be formed by combining a layer containing a composite material of an organic compound and an acceptor substance with a layer containing a transparent conductive film.

[0160] Note that, from the viewpoint of light extraction efficiency, the charge generation layer 160 and the charge generation layer 2115 are visible light On the other hand, it preferably has translucency (specifically, the transmittance of visible light with respect to the charge generation layer 160 and the charge generation layer 2115 is 40% or more). Further, the charge generation layer 160 and the charge generation layer 2115 can function even with a lower conductivity than that of a pair of electrodes (electrode 2101, electrode 2102, electrode 2103, and electrode 210 4).

[0161] By forming the charge generation layer 160 and the charge generation layer 2115 using the above-described materials, it is possible to suppress an increase in the driving voltage when the light-emitting layer is laminated.

[0162] ≪Light-emitting layer≫ The light-emitting layer 140, the light-emitting layer 2140, and the light-emitting layer 2170 have a function of exhibiting at least one emission of purple, blue, cyan, green, yellow green, yellow, orange, or red, and include a light-emitting material. Further, the light-emitting layer 140, the light-emitting layer 2140, and the light-emitting layer 2170 are configured to include one or both of an electron-transporting material or a hole-transporting material as a host material in addition to the light-emitting material

[0163] As the light-emitting material, a luminescent substance capable of converting singlet excitation energy into light emission or a luminescent substance capable of converting triplet excitation energy into light emission can be used. Examples of the luminescent substance include the following.

[0164] Examples of the luminescent substance capable of converting singlet excitation energy into light emission include substances that emit fluorescence (fluorescent compounds). The fluorescent compounds are not particularly limited, but include anthracene derivatives, tetracene derivatives, chrysene derivatives, phenanthrene derivatives, pyrene derivatives, perylene derivatives, stilbene derivatives, acridone derivatives, coumarin derivatives, phenoxazine derivatives derivatives, styrene derivatives, acridine derivatives, coumarin derivatives, phenoxazine derivatives Conductors, phenothiazine derivatives, etc. are preferable, and for example, the following substances can be used.

[0165] Specifically, 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2 ,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl -9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2 BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoro ren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn) , N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H -fluorene-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMem FLPAPrn), N,N'-bis[4-(9-phenyl-9H-fluorene-9-yl )phenyl]-N,N'-bis(4-tert-butylphenyl)-pyrene-1,6-di amine (abbreviation: 1,6tBu-FLPAPrn), N,N'-diphenyl-N,N'-bi s[4-(9-phenyl-9H-fluorene-9-yl)phenyl]-3,8-dicyclo hexylpyrene-1,6-diamine (abbreviation: ch-1,6FLPAPrn), N,N'- (pyrene-1,6-diyl)bis[(6,N-diphenylbenzo[b]naphtho[1,2- d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), N,N'-bis 4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene- 4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)-4 '-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4 -(9H-Carbazol-9-yl)-4'-(9,10-diphenyl-2-anthryl ) triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(1 0-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra(tert-butyl)perylene (abbreviation : TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H -carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), N,N''- (2-tert-butylanthracene-9,10-diyl-di-4,1-phenylene)bis [N,N',N'-triphenyl-1,4-phenylenediamine] (abbreviation: DPABPA ), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H -carbazole-3-amine (abbreviation: 2PCAPPA), N-[4-(9,1 0-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4 -phenylenediamine (abbreviation: 2DPAPPA), N,N,N',N',N'',N'' ,N''',N'''-octaphenyldibenzo[g,p]chrysene-2,7,10,1 5-tetraamine (abbreviation: DBC1), coumarin 30, N-(9,10-diphenyl-2 -anthryl)-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PC APA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthryl -N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCABPhA) , N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl-1 ,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(1,1'- (Biphenyl-2-yl)-2-anthryl]-N,N’,N’-triphenyl-1,4- phenylenediamine (abbreviation: 2DPABPhA), 9,10-bis(1,1’-biphenyl -2-yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N-phenyl anthracen-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenyl anthracen-9-amine (abbreviation: DPhAPhA), Coumarin 6, Coumarin 545T, N ,N’-diphenylquinacridone (abbreviation: DPQd), Rubrene, 2,8-di-tert -butyl-5,11-bis(4-tert-butylphenyl)-6,12-diphenyltetra acene (abbreviation: TBRb), Nile Red, 5,12-bis(1,1’-biphenyl- 4-yl)-6,11-diphenyltetracene (abbreviation: BPT), 2-(2-{2-[4 -(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-ylidene )propanedinitrile (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3,6 ,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]- 4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N’, N’-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p- mPhTD), 7,14-diphenyl-N,N,N’,N’-tetrakis(4-methylph enyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: p-m PhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl- 2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)e {2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI), 2 -{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6, 7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4 H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2,6- bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene ne)propanedinitrile (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methoxy -1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo [ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), 5,10,15,20-tetraphenylbis benz[5,6]indeno[1,2,3-cd:1’,2’,3’-lm]perylene, etc. are mentioned.

[0166] In addition, examples of the luminescent substance that can convert triplet excitation energy into luminescence include substances that emit phosphorescence (phosphorescent compounds). Examples of phosphorescent compounds include iridium, rhodium or platinum-based organometallic complexes, or metal complexes. Also, platinum complexes and organoiridium complexes having porphyrin ligands are mentioned. Among them, organoiridium complexes, for example, iridium-based orthometalated complexes are preferable. As the ligand for orthometalation, 4 H-triazole ligand, 1H-triazole ligand, imidazole ligand, pyridine ligand , pyrimidine ligand, pyrazine ligand, or isoquinoline ligand, etc. are mentioned. At this time, the phosphorescent compound is triplet MLCT (Metal to Ligand Ch has an absorption band for the (arge Transfer) migration.

[0167] Examples of substances having a light emission peak in blue or green include, for example, tris{2-[5-(2 -methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazolo -l-3-yl-κN 2 phenyl-κC}iridium(III) (abbreviation: Ir(mpp tz-dmp)3), tris(5-methyl-3,4-diphenyl-4H-1,2,4-tri azolato)iridium(III) (abbreviation: Ir(Mptz)3), tris[4-(3- biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]i ridium(III) (abbreviation: Ir(iPrptz-3b)3), tris[3-(5-bip enyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]iridi um(III) (abbreviation: Ir(iPr5btz)3), such as organometallic iridium complexes having a 4H-triazole skeleton and tris[3-methyl-1-(2-methylphenyl) -5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: Ir (Mptz1-mp)3), tris(1-methyl-5-phenyl-3-propyl-1H- 1,2,4-triazolato)iridium(III) (abbreviation: Ir(Prptz1-Me) 3) and other organometallic iridium complexes having a 1H-triazole skeleton, and fac-tri s[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]i ridium(III) (abbreviation: Ir(iPrpmi)3), tris[3-(2,6-dime thylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(I II) (Abbreviation: Ir(dmpimpt-Me)3), which has an imidazole skeleton Organometallic iridium complexes such as N,C 2’ iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation: FI r6), bis[2-(4’,6’-difluorophenyl)pyridinato-N,C 2’ iri dium(III) picolinate (abbreviation: FIrpic), bis{2-[3’,5’-bis (trifluoromethyl)phenyl]pyridinato-N,C 2’}iridium(III) pico linate (abbreviation: Ir(CF3ppy)2(pic)), bis[2-(4’,6’-dif luorophenyl)pyridinato-N,C 2’ iridium(III) acetylacetonate (abbreviation: FIr(acac)), and organometallic iridium complexes having a phenylpyridine derivative having an electron-withdrawing group such as are exemplified. Among those described above, organometallic iridium complexes having a nitrogen-containing five-membered heterocyclic skeleton such as a 4H-triazole skeleton, a 1H-triazole skeleton, and an imidazole skeleton have high triplet excitation energy and are particularly preferable because they are excellent in reliability and luminescence efficiency.

[0168] In addition, examples of substances having a luminescence peak in green or yellow include tris(4-methyl -6-phenylpyrimidinato)iridium(III) (abbreviation: Ir(mppm)3), tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: I r(tBuppm)3), (acetylacetonato)bis(6-methyl-4-phenylpyr imidinato)iridium(III) (abbreviation: Ir(mppm)2(acac)), (acetyl Bis(6-tert-butyl-4-phenylpyrimidinato)(acetylacetonato)iridium(III) (abbreviation: Ir(tBuppm)2(acac)), bis [4-(2-norbornyl)-6-phenylpyrimidinato]iridium(III) (abbreviation : Ir(nbppm)2(acac)), bis [5-methyl-6 -(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: Ir(mpmppm)2(acac)), bis{4,6-dimethyl -2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN3]phenyl- κC}iridium(III) (abbreviation: Ir(dmppm-dmp)2(acac)), Bis(4,6-diphenylpyrimidinato)(acetylacetonato)iridium(III) ( abbreviation: Ir(dppm)2(acac)) and other organometallic iridium complexes having a pyrimidine skeleton, bis(3,5-dimethyl-2-phenylpyrazinato)(acetylacetonato)iridium(III) ( abbreviation: Ir(mppr-Me)2(acac)), bis(5-isopropyl-3-methyl-2-phenylpyrazinato)(acetylacetonato)iridium(III) ( abbreviation: Ir(mppr-iPr)2(acac)) and other organometallic iridium complexes having a pyrazine skeleton, tris(2-phenylpyridinato-N,C ) iridium(III) (abbreviation: Ir(ppy)3), bis(2-phenylpyridinato-N ,C 2’ ) iridium(III) acetylacetonate (abbreviation: Ir(ppy)2(ac ,C 2’ ac)), bis(benzo[h]quinolinato)iridium(III) acetylacetonate and bis(2-phenylpyridinato-N,C (Abbreviation: Ir(bzq)2(acac)), tris(benzo[h]quinolinato)iridium (III) (Abbreviation: Ir(bzq)3), tris(2-phenylquinolinato-N,C 2 ’ )iridium(III) (Abbreviation: Ir(pq)3), bis(2-phenylquinolinato- N,C 2’ )iridium(III) acetylacetonate (Abbreviation: Ir(pq)2(ac ac)), and other organometallic iridium complexes having a pyridine skeleton, such as bis(2,4-dif enyl-1,3-oxazolato-N,C 2’ )iridium(III) acetylacetonate (Abbreviation: Ir(dpo)2(acac)), bis{2-[4’-(perfluorophen yl)phenyl]pyridinato-N,C 2’}iridium(III) acetylacetonate( Abbreviation: Ir(p-PF-ph)2(acac)), bis(2-phenylbenzothiazolato -N,C 2’ )iridium(III) acetylacetonate (Abbreviation: Ir(bt)2(a cac)), and other organometallic iridium complexes, as well as rare earth metal complexes such as tris(acetylacetonato)(monophen anthroline)terbium(III) (Abbreviation: Tb(acac)3(Phen)). Among the above, organometallic iridium complexes having a pyrimidine skeleton are particularly preferred because of their outstanding reliability and luminescence efficiency. In addition, examples of substances having a luminescence peak in yellow or red include, for example, (diisobutyryl methanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(II

[0169] I) (Abbreviation: Ir(5mdppm)2(dibm)), bis[4,6-bis(3-methyl phenyl ​(Phenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: Ir (5mdppm)2(dpm)), bis[4,6-bis(naphthalen-1-yl)pyrimidin inato](dipivaloylmethanato)iridium(III) (abbreviation: Ir(d1npm)2( dpm)) and other organometallic iridium complexes having a pyrimidine skeleton, (acetylacet tonato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviation: I r(tppr)2(acac)), bis(2,3,5-triphenylpyrazinato)(dip valoylmethanato)iridium(III) (abbreviation: Ir(tppr)2(dpm)), ( (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]i ridium(III) (abbreviation: Ir(Fdpq)2(acac)) and other organometallic iridium complexes having a pyrazine skeleton, tris(1-phenylisoquinolinato-N,C ) 2’ ) iridium(III) (abbreviation: Ir(piq)3), bis(1-phenylisoquinolinato -N,C 2’ )iridium(III) acetylacetonate (abbreviation: Ir(piq)2( acac)) and other organometallic iridium complexes having a pyridine skeleton, in addition to 2,3,7, 8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II )(abbreviation: PtOEP) and other platinum complexes, tris(1,3-diphenyl-1,3-prop anedionato)(monophenanthroline)europium(III) (abbreviation: Eu(DB M)3(Phen)), tris[1-(2-thenoyl)-3,3,3-trifluoroace tonato](monophenanthroline)europium(III) (abbreviation: Eu(TTA)3( Examples include rare earth metal complexes such as Organometallic iridium complexes having a pyrimidine skeleton are particularly preferred because they are outstanding in reliability and luminescence efficiency. In addition, organometallic iridium complexes having a pyrazine skeleton can obtain red luminescence with good chromaticity.

[0170] In addition, as materials that can convert triplet excitation energy into luminescence, in addition to phosphorescent compounds, thermally activated delayed fluorescence (TADF) materials can be mentioned. Therefore, with respect to the part described as a phosphorescent compound, it may be read as a thermally activated delayed fluorescent compound. Thermally activated delayed fluorescent compounds have a small difference between the singlet excitation energy level and the triplet excitation energy level, and have a function of converting triplet excitation energy into singlet excitation energy by reverse intersystem crossing. Therefore, the triplet excited state can be upconverted (reverse intersystem crossing) to the singlet excited state by a small amount of thermal energy, and luminescence (fluorescence) from the singlet excited state can be efficiently presented. Conditions for efficiently obtaining thermally activated delayed fluorescence include that the difference between the singlet excitation energy level and the triplet excitation energy level is preferably greater than 0 eV and 0.3 eV or less, more preferably greater than 0 eV and 0.2 eV or less, and still more preferably greater than 0 eV and 0.1 eV or less.

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

[0172] First, examples include fullerenes and their derivatives, acridine derivatives such as proflavine, and eosin. ​​​​​​is also mentioned. In addition, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd), etc. are mentioned. n), platinum (Pt), indium (In), or palladium (Pd), etc. are mentioned. Examples of the metal-containing porphyrin include protoporphyrin-tin fluoride complex (SnF2(Proto IX)), mesoporphyrin-tin fluoride complex (SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (Sn F2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (SnF2(Copro III-4Me)), octaethylporphyrin-tin fluoride complex (SnF2(OEP)), etioporphyrin-tin fluoride complex (SnF2(E tio I)), octaethylporphyrin-platinum chloride complex (PtCl2OEP), etc. Examples include protoporphyrin-tin fluoride complex (SnF2(Proto IX)), mesoporphyrin-tin fluoride complex (SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (Sn F2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (SnF2(Copro III-4Me)), octaethylporphyrin-tin fluoride complex (SnF2(OEP)), etioporphyrin-tin fluoride complex (SnF2(E tio I)), octaethylporphyrin-platinum chloride complex (PtCl2OEP), etc. Examples include protoporphyrin-tin fluoride complex (SnF2(Proto IX)), mesoporphyrin-tin fluoride complex (SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (Sn F2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (SnF2(Copro III-4Me)), octaethylporphyrin-tin fluoride complex (SnF2(OEP)), etioporphyrin-tin fluoride complex (SnF2(E

[0173] In addition, as a thermally activated delayed fluorescence compound composed of a single material, heterocyclic compounds having a π-electron rich heteroaromatic skeleton and a π-electron deficient heteroaromatic skeleton can also be used. Specifically, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC -TRZ), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H -carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2-[4-(10H-phenoxazine-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3- [4-(5-phenyl-5,10-dihydrophenazine-10-yl)phenyl]-4, (abbreviation: PXZ-TRZ), 3- [4-(5-phenyl-5,10-dihydrophenazine-10-yl)phenyl]-4, [4-(5-phenyl-5,10-dihydrophenazine-10-yl)phenyl]-4, 5-Diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9 -Dimethyl-9H-acridin-10-yl)-9H-xanthen-9-one (abbreviation: A CRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridin)phenyl yl]sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10’H-spiro [acridine-9,9’-anthracene]-10’-one (abbreviation: ACRSA), etc. are listed. Since the heterocyclic compound has a π-electron-excessive heterocyclic aromatic skeleton and a π-electron-deficient heterocyclic aromatic skeleton, it has high electron transportability and hole transportability, which is preferable. Among them, among the π-electron-deficient heterocyclic aromatic skeletons, a diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton) , or a triazine skeleton is preferable because it is stable and has good reliability. Also, among the π-electron-excessive heterocyclic aromatic skeletons, an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, and a pyrrole skeleton are stable and have good reliability, so it is preferable to have any one or more selected from these skeletons. As the pyrrole skeleton, an indole skeleton, a carbazole skeleton, and a 9-phenyl-3,3’-bi- 9H-carbazole skeleton are particularly preferable. Note that a substance in which a π-electron-excessive heterocyclic aromatic skeleton and a π-electron deficient heterocyclic aromatic skeleton are directly bonded has both strong donor properties of the π-electron-excessive heterocyclic aromatic skeleton and acceptor properties of the π-electron-deficient heterocyclic aromatic skeleton, and the difference between the singlet excitation energy level and the triplet excitation energy level becomes small, so it is particularly preferable.

[0174] Also, a material that exhibits thermally activated delayed fluorescence, alone, undergoes reverse intersystem crossing from the triplet excited state to the singlet It may be a material capable of generating a triplet excited state, or may be composed of a plurality of materials that form an exciplex (also called an exciplex or Exciplex). It may also be composed of a plurality of materials that form an exciplex (also called an exciplex or Exciplex).

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

[0176] In addition, the material that can be used as the host material of the light-emitting layer is not particularly limited, but for example, tris(8-quinolinolato)aluminum(III) (abbreviation: Alq3), tris (4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq3), bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq 2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum (III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq ), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPB O), bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBT Z), and other metal complexes, 2-(4-biphenylyl)-5-(4-tert-butylphenyl )-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-ter t-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: O XD-7), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl yl)-1,2,4-triazole (abbreviation: TAZ), 2,2’,2’’-(1,3, 5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: T PBI), Bathocuproine (abbreviation: BCP), 9-[4-(5-phenyl-1,3,4 -Oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11) Which heterocyclic compound, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl N,N'-bis(3-methylphenyl)-N ,N'-Diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD) , 4,4'-bis[N-(spiro-9,9'-bifluoren-2-yl)-N-phenyl Examples of aromatic amine compounds include aromatic amine compounds such as phenylamino]biphenyl (abbreviation: BSPB). Anthracene derivatives, phenanthrene derivatives, pyrene derivatives, chrysene derivatives, dibenzo [g,p]Chrysene derivatives and other condensed polycyclic aromatic compounds are included. -Diphenylanthracene (abbreviation: DPAnth), N,N-diphenyl-9-[4-( 10-Phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation : CzA1PA), 4-(10-phenyl-9-anthryl)triphenylamine (abbreviation :DPhPA), YGAPA, PCAPA, N,9-diphenyl-N-{4-[4-(1 0-Phenyl-9-anthryl)phenyl]phenyl}-9H-carbazole-3-amine PCAPBA, 2PCAPA, 6,12-dimethoxy-5,11-diphenyl Luchrysene, DBC1, 9-[4-(10-phenyl-9-anthracenyl)phenyl] -9H-Carbazole (abbreviation: CzPA), 3,6-diphenyl-9-[4-(10-phenyl [phenyl-9-anthryl]phenyl]-9H-carbazole (abbreviation: DPCzPA), ,10-Bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 9,1 0-di(2-naphthyl)anthracene (abbreviation: DNA), 2-tert-butyl-9,1 0-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 9,9'-bianthry l (abbreviation: BANT), 9,9'-(stilbene-3,3'-diyl)diphenanthrene (abbreviation: DPNS), 9,9'-(stilbene-4,4'-diyl)diphenanthrene ( abbreviation: DPNS2), 1,3,5-tri(1-pyrenyl)benzene (abbreviation: TPB3) and the like can be mentioned. From among these and various substances, a substance having an energy gap larger than the energy gap of the above light-emitting material can be selected and used alone or in combination of two or more. When the light-emitting material is a phosphorescent compound, as the host material, a substance having a triplet excitation energy larger than the triplet excitation energy of the light-emitting material may be selected. Moreover, when a plurality of materials are used as the host material of the light-emitting layer, it is preferable to use a combination of two types of compounds that form an exciplex. In this case, various carrier transport materials can be used as appropriate, but in order to efficiently form an exciplex, it is particularly preferable to combine an electron transport material and a hole transport material. This is because when an exciplex is formed by combining an electron transport material and a hole transport material as the host material, it becomes easy to optimize the carrier balance between holes and electrons in the light-emitting layer. By optimizing the carrier balance between holes and electrons in the light-emitting layer, it is possible to suppress the deviation of the region where recombination between electrons and holes occurs in the light-emitting layer. Suppressing the deviation of the recombination region can Moreover, when a plurality of materials are used as the host material of the light-emitting layer, it is preferable to use a combination of two types of compounds that form an exciplex. In this case, various carrier transport materials can be used as appropriate, but in order to efficiently form an exciplex, it is particularly preferable to combine an electron transport material and a hole transport material.

[0177] This is because when an exciplex is formed by combining an electron transport material and a hole transport material as the host material, it becomes easy to optimize the carrier balance between holes and electrons in the light-emitting layer. By optimizing the carrier balance between holes and electrons in the light-emitting layer, it is possible to suppress the deviation of the region where recombination between electrons and holes occurs in the light-emitting layer. Suppressing the deviation of the recombination region can Moreover, when a plurality of materials are used as the host material of the light-emitting layer, it is preferable to use a combination of two types of compounds that form an exciplex. In this case, various carrier transport materials can be used as appropriate, but in order to efficiently form an exciplex, it is particularly preferable to combine an electron transport material and a hole transport material. This is because when an exciplex is formed by combining an electron transport material and a hole transport material as the host material, it becomes easy to optimize the carrier balance between holes and electrons in the light-emitting layer. By optimizing the carrier balance between holes and electrons in the light-emitting layer, it is possible to suppress the deviation of the region where recombination between electrons and holes occurs in the light-emitting layer. Suppressing the deviation of the recombination region can

[0178] Moreover, when a plurality of materials are used as the host material of the light-emitting layer, it is preferable to use a combination of two types of compounds that form an exciplex. In this case, various carrier transport materials can be used as appropriate, but in order to efficiently form an exciplex, it is particularly preferable to combine an electron transport material and a hole transport material. This is because when an exciplex is formed by combining an electron transport material and a hole transport material as the host material, it becomes easy to optimize the carrier balance between holes and electrons in the light-emitting layer. By optimizing the carrier balance between holes and electrons in the light-emitting layer, it is possible to suppress the deviation of the region where recombination between electrons and holes occurs in the light-emitting layer. Suppressing the deviation of the recombination region can Moreover, when a plurality of materials are used as the host material of the light-emitting layer, it is preferable to use a combination of two types of compounds that form an exciplex. In this case, various carrier transport materials can be used as appropriate, but in order to efficiently form an exciplex, it is particularly preferable to combine an electron transport material and a hole transport material. ​​​​Thus, the reliability of the light-emitting element can be improved.

[0179] As the electron transporting material, a metal complex having zinc or aluminum, a π-electron deficient heteroaromatic compound such as a nitrogen-containing heteroaromatic compound, or the like can be used. Specifically, bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq 2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum (III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq ), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPB O), bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBT Z), and other metal complexes, 2-(4-biphenylyl)-5-(4-tert-butylphenyl yl)-1,3,4-oxadiazole (abbreviation: PBD), 3-(4-biphenylyl)-4 -phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation : TAZ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxa diazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl- 1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: C O11), 2,2’,2’’-(1,3,5-benzenetriyl)tris(1-phenyl -1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophene- 4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBI m-II), and other heterocyclic compounds having an azole skeleton, 2-[3-(dibenzothiophene N-4-yl)phenyl]dibenz[f,h]quinoxaline (abbreviation: 2mDBTPDBq -II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenz enzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9 H-carbazol-9-yl)biphenyl-3-yl]dibenz[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H-carbazol -9-yl)phenyl]dibenz[f,h]quinoxaline (abbreviation: 2CzPDBq-II I), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenz[f,h]quin oxaline (abbreviation: 7mDBTPDBq-II), and 6-[3-(dibenzothiophen -4-yl)phenyl]dibenz[f,h]quinoxaline (abbreviation: 6mDBTPDBq- II), 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation : 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]py rimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carb azole-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 4-{3- [3'-(9H-carbazol-9-yl)]biphenyl-3-yl}benzofuro[3,[[]] 2-d]pyrimidine (abbreviation: 4mCzBPBfpm) and other heterocyclic compounds having a diazine skeleton, 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H- carbazol-9-yl)phenyl}-4,6-diphenyl-1,3,5-triazine ( abbreviation: PCCzPTzn), 2,4,6-tris[3'-(pyridin-3-yl)biphe nyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz), 2,4,6- Heterocyclic compounds having a triazine skeleton such as tris(2-pyridyl)-1,3,5-triazine (abbreviation: 2Py3Tzn), and heterocyclic compounds having a diazine skeleton, and 3,5-bis[3-(9H-carbazol-9-yl phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridyl yl)phenyl]benzene (abbreviation: TmPyPB) and other heterocyclic compounds having a pyridine skeleton are exemplified. Among the above, heterocyclic compounds having a diazine skeleton and a triazine skeleton and heterocyclic compounds having a pyridine skeleton are preferred because of their good reliability. In particular, heterocyclic compounds having a diazine (pyrimidine or pyrazine) skeleton and a triazine skeleton have high electron transport properties and contribute to reducing the driving voltage.

[0180] As the hole transport material, a π-electron excess type heteroaromatic (for example, a carbazole derivative or an indole derivative) or an aromatic amine can be preferably used. Specifically, 2- N-(9-phenylcarbazol-3-yl)-N-phenylamino]spiro-9,9’ -bifluorene (abbreviation: PCASF), 4,4’,4’’-tris[N-(1-naphthyl )-N-phenylamino]triphenylamine (abbreviation: 1’-TNATA), 2,7-bis [N-(4-diphenylaminophenyl)-N-phenylamino]spiro-9,9’- bifluorene (abbreviation: DPA2SF), N,N’-bis(9-phenylcarbazol-3 -yl)-N,N’-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N -(9,9-dimethyl-2-diphenylamino-9H-fluoren-7-yl)diphenyl amine (abbreviation: DPNF), N,N’,N’’-triphenyl-N,N’,N’’-tri Liss(9-phenylcarbazol-3-yl)benzene-1,3,5-triamine (abbreviation : PCA3B), 2-[N-(9-phenylcarbazol-3-yl)-N-phenyl a mino]spiro-9,9'-bifluorene (abbreviation: PCASF), 2-[N-(4-diphe nylaminophenyl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: DPASF), N,N'-bis[4-(carbazol-9-yl)phenyl]-N,N' -diphenyl-9,9-dimethylfluorene-2,7-diamine (abbreviation: YGA2F), 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NP B), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-bi phenyl]-4,4'-diamine (abbreviation: TPD), 4,4'-bis[N-(4-diphe nylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), 4,4' -bis[N-(spiro-9,9'-bifluorene-2-yl)-N-phenylamino]bi phenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluorene-9-i l)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenyl fluorene-9-yl)triphenylamine (abbreviation: mBPAFLP), N-(9,9- dimethyl-9H-fluorene-2-yl)-N-{9,9-dimethyl-2-[N'-phe nyl-N'-(9,9-dimethyl-9H-fluorene-2-yl)amino]-9H-flu orene-7-yl}phenylamine (abbreviation: DFLADFL), 3-[N-(9-pheni lucarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation : PCzPCA1), 3-[N-(4-diphenylaminophenyl)-N-phenylami n]-9-phenylcarbazole (abbreviation: PCzDPA1), 3,6-bis[N-(4- diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation : PCzDPA2), N,N'-bis{4-[bis(3-methylphenyl)amino]phen yl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviation : DNTPD), 3,6-bis[N-(4-diphenylaminophenyl)-N-(1-naph thyl)amino]-9-phenylcarbazole (abbreviation: PCzTPN2), 3,6-bis [N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenyl carbazole (abbreviation: PCzPCA2), 4-phenyl-4'-(9-phenyl-9H- carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-di phenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamin e (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H- carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di( 1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenyl lamine (abbreviation: PCBNBB), 3-[N-(1-naphthyl)-N-(9-phenylcarb azol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1) 、9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol- 3-yl)phenyl]fluorene-2-amine (abbreviation: PCBAF), N-phenyl-N -[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9' -Bifluoren-2-amine (abbreviation: PCBASF), N-(4-biphenyl)-N- 9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-carbazole -3-amine (abbreviation: PCBiF), N-(1,1'-biphenyl-4-yl)-N- 4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl- 9H-fluoren-2-amine (abbreviation: PCBBiF), etc., compounds having an aromatic amine skeleton, and 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di (N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenyl phenyl)-9-phenylcarbazole (abbreviation: CzTP), 9-phenyl-9H-3- (9-phenyl-9H-carbazol-3-yl)carbazole (abbreviation: PCCP), etc. compounds having a carbazole skeleton, and 4,4',4''-(benzene-1,3,5-tri yl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl -4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiop ene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluoren- 9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV) compounds having a thiophene skeleton, and 4,4',4''-(benzene-1,3,5- triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), 4-{3-[3-(9 -phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation :mmDBFFLBi-II), etc., compounds having a furan skeleton. Among the above-mentioned compounds, compounds having an aromatic amine skeleton and compounds having a carbazole skeleton have high reliability is good, has high hole transportability, and is preferable because it also contributes to reducing the driving voltage.

[0181] In addition, the combination of host materials that form an exciplex is not limited to the above-described compounds, and is a combination that can transport carriers and form an exciplex, and the emission of the exciplex only needs to overlap with the absorption band on the longest wavelength side in the absorption spectrum of the light-emitting material (the absorption corresponding to the transition from the singlet ground state to the singlet excited state of the light-emitting material), and other materials may be used. From the singlet ground state of the light-emitting material to the singlet excited state), and other materials may be used. may be used.

[0182] In addition, a thermally activated delayed fluorescence material may be used as the host material used in the light-emitting layer.

[0183] In addition, the same material as the electron transport material used in the electron injection layer can be used for the electron transport material used in the light-emitting layer. By doing so, the fabrication of the light-emitting element can be performed simply, and the manufacturing cost of the light-emitting element can be reduced. the manufacturing cost of the light-emitting element can be reduced.

[0184] ≪Electron transport layer≫ The electron transport layer 118, the electron transport layer 2113, and the electron transport layer 2118 are layers containing a substance with high electron transportability. In the electron transport layer 118, the electron transport layer 2113, and the electron transport layer 2118, there are metal complexes having a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, pyridine derivatives, bipyridine derivatives, and the like. Specifically, the metal complexes and heteroaromatic compounds exemplified as the compounds that can be used in the electron injection layer 130, the electron injection layer 2130, and the electron injection layer 2119 can be used. Note that electrons rather than holes there are metal complexes having a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, pyridine derivatives, bipyridine derivatives, and the like. Specifically, the metal complexes and heteroaromatic compounds exemplified as the compounds that can be used in the electron injection layer 130, the electron injection layer 2130, and the electron injection layer 2119 can be used. Note that electrons rather than holes there are metal complexes having a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, pyridine derivatives, bipyridine derivatives, and the like. Specifically, the metal complexes and heteroaromatic compounds exemplified as the compounds that can be used in the electron injection layer 130, the electron injection layer 2130, and the electron injection layer 2119 can be used. Note that electrons rather than holes there are metal complexes having a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, pyridine derivatives, bipyridine derivatives, and the like. Specifically, the metal complexes and heteroaromatic compounds exemplified as the compounds that can be used in the electron injection layer 130, the electron injection layer 2130, and the electron injection layer 2119 can be used. Note that electrons rather than holes In addition, the metal complexes and heteroaromatic compounds exemplified as the compounds that can be used in the electron injection layer 130, the electron injection layer 2130, and the electron injection layer 2119 can be used. Note that electrons rather than holes In addition, the metal complexes and heteroaromatic compounds exemplified as the compounds that can be used in the electron injection layer 130, the electron injection layer 2130, and the electron injection layer 2119 can be used. Note that electrons rather than holes If the material has a high transporting property, the material other than the above can be used for the electron transport layer 118 and the electron transport layer 2113. and may be used as the electron-transporting layer 2118 .

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

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

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

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

[0189] As the quantum dots, colloidal quantum dots, alloy-type quantum dots, core-shell type quantum dots, core-type quantum dots, etc. may be used. Also, quantum dots containing element groups of Group 2 and Group 16, Group 13 and Group 15, Group 13 and Group 17, Group 11 and Group 17, or Group 14 and Group 15 may be used. Alternatively, quantum dots having elements such as cadmium (Cd), selenium (Se), zinc (Zn ), sulfur (S), phosphorus (P), indium (In), tellurium (Te), lead (Pb), gallium (Ga ), arsenic (As), aluminum (Al), etc. may be used.

[0190] As the liquid medium used in the wet process, for example, ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, halogenated hydrocarbons such as dichlorobenzene, aromatic hydrocarbons such as toluene, xylene, mesitylene, and cyclohexylbenzene, aliphatic hydrocarbons such as cyclohexane, decalin, and dodecane, and organic solvents such as dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) can be used.

[0191] In addition, examples of the polymeric compounds that can be used for the light-emitting layer include poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (abbreviation: MEH -PPV), polyphenylenevinylene (PPV) derivatives such as poly(2,5-dioctyl-1,4-phenylenevinylene), poly(9,9-di-n-octylfluorenyl-2,7 ​ -diyl) (abbreviation: PF8), poly[(9,9-di-n-octylfluorenyl-2,7 -diyl)-alt-(benzo[2,1,3]thiadiazole-4,8-diyl)] (abbreviation : F8BT), poly[(9,9-di-n-octylfluorenyl-2,7-diyl)- alt-(2,2'-bithiophene-5,5'-diyl)] (abbreviation F8T2), poly (9,9-dioctyl-2,7-divinylenefluorenylene)-alt-(9,10-anthra cene)], poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-( 2,5-dimethyl-1,4-phenylene)] and other polyfluorene derivatives, poly(3-hex ylthiophene-2,5-diyl) (abbreviation: P3HT) and other polyalkylthiophene (P AT) derivatives, polyphenylene derivatives, etc. Further, these polymer compounds and poly(9-vinylcarbazole) (abbreviation: PVK), poly(2-vinylnaphthalene), po ly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (abbreviation: PTA A) and other polymer compounds may be doped with a light-emitting low-molecular compound and used for the light-emitting layer. As the light-emitting low-molecular compound, the fluorescent compounds mentioned above can be used.

[0192] ≪A pair of electrodes≫ Electrodes 101, 102, 2101, 2102, 2103 and 210 4 have a function as an anode or a cathode of the light-emitting element. Electrodes 101, 102, electrodes 2101, 2102, 2103 and 2104 can be formed using metals, alloys, conductive compounds , and mixtures or laminates thereof.

[0193] Either the electrode 101 or the electrode 102, the electrode 2101, the electrode 2103, and the electrode 2104 or the electrode 2102 is preferably formed of a conductive material having a function of reflecting light. Examples of such a conductive material include aluminum (Al) or an alloy containing Al. Examples of alloys containing Al include alloys containing Al and L (where L represents one or more of titanium (Ti), neodymium (Nd), nickel (Ni), and lanthanum (La)), such as alloys containing Al and Ti, or alloys containing Al and Ni and La. Aluminum has a low resistance value and a high light reflectance. In addition, since aluminum is abundant in the earth's crust and inexpensive, the production cost of the light-emitting element can be reduced by using aluminum. Also, silver (Ag) can be suitably used as an electrode material because it has a high light reflectance. Further, Ag is a Group 11 transition metal, and when Ag is used as the cathode of a light-emitting element using Ag in the electron injection layer, which is one aspect of the present invention, it is preferable because the adhesion between the electrode and the electron injection layer is improved. Alternatively, an alloy containing Ag and N (where N represents one or more of yttrium (Y), Nd, magnesium (Mg), ytterbium (Yb), Al, Ti, gallium (Ga), zinc (Zn), indium (In), tungsten (W), manganese (Mn), tin (Sn), iron (F e), Ni, copper (Cu), palladium (Pd), iridium (Ir), or gold (Au)) can also be used. Examples of alloys containing silver include alloys containing silver, palladium, and copper, alloys containing silver and copper, alloys containing silver and magnesium, alloys containing silver and nickel, alloys containing silver and gold, alloys containing silver and ytterbium, etc. In addition, tungsten, chromium (Cr), molybdenum (Mo), copper, titanium, etc. A transition metal can be used.

[0194] In addition, the light emission obtained from the light emitting layer passes through one or both of the electrodes 101 and 102, the electrode 2101, the electrodes 2103 and 2104 or one or both of the electrodes 2102. Thus, at least one of the electrodes 101 or 102, the electrode 210 1, the electrodes 2103 and 2104 or at least one of the electrodes 2102 is preferably formed of a conductive material having a function of transmitting light. As the conductive material, the transmittance of visible light is 40% or more and 100% or less, preferably 60% or more and 100% or less, and its resistivity is 1×10 Ω·cm or less. Examples of the conductive material include a conductive material having a transmittance of visible light of 40% or more and 100% or less, preferably 60% or more and 100% or less, and a resistivity of 1×10 Ω·cm or less. -2 Ω·cm or less.

[0195] In addition, the electrodes 101, 102, 2101, 2102, 2103 and the electrode 2104 may be formed of a conductive material having a function of transmitting light and a function of reflecting light. As the conductive material, the reflectance of visible light is 20% or more and 80% or less, preferably 40% or more and 70% or less, and its resistivity is 1×10 Ω·cm or less. -2 Ω·cm or less. Examples of the conductive material include a conductive material having a reflectance of visible light of 20% or more and 80% or less, preferably 40% or more and 70% or less, and a resistivity of 1×10 Ω·cm or less. For example, it can be formed by using one or more kinds of a conductive metal, alloy, conductive compound, etc. Specifically, for example, indium tin oxide (Indi um Tin Oxide, hereinafter referred to as ITO), indium tin oxide containing silicon or silicon oxide (abbreviation: ITSO), indium zinc oxid e, indium tin oxide containing titanium, indium titanate, indium oxide containing tungsten oxide and zinc oxide, and other metal oxides can be used. e), indium tin oxide containing titanium, indium titanate, indium oxide containing tungsten oxide and zinc oxide, and other metal oxides can be used. e, indium tin oxide containing titanium, indium titanate, indium oxide containing tungsten oxide and zinc oxide, and other metal oxides can be used. Moreover, a metal thin film that allows light to pass through (preferably with a thickness of 1 nm or more and 30 nm or less) can be used. As the metal, for example, Ag, or an alloy such as an alloy of Ag and Al, Ag and Mg, Ag and Au, Ag and Yb, etc. can be used.

[0196] It is preferable that the conductive layer 2101b, the conductive layer 2103b, and the conductive layer 2104b are formed of a conductive material having the above-described function of transmitting light. Also, the conductive layer 2101a, the conductive layer 2103a, and the conductive layer 2104a are preferably formed of a conductive material having the function of reflecting the above-described light, a conductive material having the function of transmitting light, or a conductive material having both the function of transmitting light and the function of reflecting light.

[0197] In addition, in this specification and the like, a material having the function of transmitting light may be any material that has the function of transmitting visible light and has conductivity. For example, in addition to the oxide conductors represented by ITO as described above, it includes oxide semiconductors or organic conductors containing organic substances. Examples of organic conductors containing organic substances include composite materials formed by mixing an organic compound and an electron donor (donor), composite materials formed by mixing an organic compound and an electron acceptor (acceptor), and the like. In addition, inorganic carbon-based materials such as graphene may be used. Also, the resistivity of the material is preferably 1 × 10 Ω·cm or less, more preferably 1 × 10 Ω·cm or less. 5 4

[0198] Moreover, by laminating a plurality of the above materials, one or both of the electrodes 101 and 102, and one or both of the electrodes 2101, 2103, and 2104 or the electrode 2102 may be formed. ​​​​​​​​​

[0199] In addition, in order to improve the light extraction efficiency, it may be formed of a material having a refractive index higher than that of the electrode in contact with an electrode having a function of transmitting light. Such a material may be any material having a function of transmitting visible light, whether it is a conductive material or a non-conductive material. For example, in addition to the above-described oxide conductor, an oxide semiconductor and an organic material may be mentioned. As such a material, any material having a function of transmitting visible light may be used, whether it is a conductive material or a non-conductive material. For example, in addition to the above-described oxide conductor, an oxide semiconductor and an organic material may be mentioned. As such a material, any material having a function of transmitting visible light may be used, whether it is a conductive material or a non-conductive material. For example, in addition to the above-described oxide conductor, an oxide semiconductor and an organic material may be mentioned. For example, in addition to the above-described oxide conductor, an oxide semiconductor and an organic material may be mentioned. Examples of the organic material include the materials exemplified for the light-emitting layer, the hole injection layer, the hole transport layer, the electron transport layer, or the electron injection layer. Further, an inorganic carbon-based material or a metal thin film that allows light to pass through may also be used, and a plurality of layers having a thickness of several nm to several tens of nm may be laminated. Examples of the organic material include the materials exemplified for the light-emitting layer, the hole injection layer, the hole transport layer, the electron transport layer, or the electron injection layer. Further, an inorganic carbon-based material or a metal thin film that allows light to pass through may also be used, and a plurality of layers having a thickness of several nm to several tens of nm may be laminated. Examples of the organic material include the materials exemplified for the light-emitting layer, the hole injection layer, the hole transport layer, the electron transport layer, or the electron injection layer. Further, an inorganic carbon-based material or a metal thin film that allows light to pass through may also be used, and a plurality of layers having a thickness of several nm to several tens of nm may be laminated.

[0200] When the electrode 101 or the electrode 102 functions as a cathode, it preferably has a material having a small work function (3.8 eV or less). When either the electrode 2101, the electrode 2103, and the electrode 2104 or the electrode 2102 functions as a cathode, it preferably has a material having a small work function (3.8 eV or less). When the electrode 101 or the electrode 102 functions as a cathode, it preferably has a material having a small work function (3.8 eV or less). When either the electrode 2101, the electrode 2103, and the electrode 2104 or the electrode 2102 functions as a cathode, it preferably has a material having a small work function (3.8 eV or less). When either the electrode 2101, the electrode 2103, and the electrode 2104 or the electrode 2102 functions as a cathode, it preferably has a material having a small work function (3.8 eV or less). When either the electrode 2101, the electrode 2103, and the electrode 2104 or the electrode 2102 functions as a cathode, it preferably has a material having a small work function (3.8 eV or less).

[0201] When the electrode 101 or the electrode 102 is used as an anode, it is preferable to use a material having a large work function (4.0 eV or more). When either the electrode 2101, the electrode 2103, and the electrode 2104 or the electrode 2102 is used as an anode, it is preferable to use a material having a large work function (4.0 eV or more). When the electrode 101 or the electrode 102 is used as an anode, it is preferable to use a material having a large work function (4.0 eV or more). When either the electrode 2101, the electrode 2103, and the electrode 2104 or the electrode 2102 is used as an anode, it is preferable to use a material having a large work function (4.0 eV or more). When either the electrode 2101, the electrode 2103, and the electrode 2104 or the electrode 2102 is used as an anode, it is preferable to use a material having a large work function (4.0 eV or more). When either the electrode 2101, the electrode 2103, and the electrode 2104 or the electrode 2102 is used as an anode, it is preferable to use a material having a large work function (4.0 eV or more).

[0202] In addition, the electrodes 101 and 102 may be a laminate of a conductive material having a function of reflecting light and a conductive material having a function of transmitting light. In that case, the electrodes 101 and 102 In addition, the electrodes 101 and 102 may be a laminate of a conductive material having a function of reflecting light and a conductive material having a function of transmitting light. In that case, the electrodes 101 and 102 02 can preferably have a function of adjusting the optical distance so as to resonate light of a desired wavelength from each light-emitting layer and enhance the light of the desired wavelength. Similarly, either one of electrode 2 101, electrode 2103, and electrode 2104 or electrode 2102 may also be a laminate of a conductive material having a function of reflecting light and a conductive material having a function of transmitting light. In that case, electrode 2101, electrode 2102, electrode 2103, and electrode 2104 can preferably have a function of adjusting the optical distance so as to resonate light of a desired wavelength from each light-emitting layer and enhance the light of the desired wavelength.

[0203] The film formation methods of electrode 101, electrode 102, electrode 2101, electrode 2102, electrode 2103, and electrode 210 4 can be appropriately used, such as sputtering method, evaporation method, printing method, coating method, MBE (Molecular Beam Epitaxy) method, CVD method, pulsed laser deposition method, ALD (Atomic Layer Deposition) method, etc.

[0204] ≪Microcavity structure≫ Further, in the light-emitting element which is one aspect of the present invention, for example, electrode 2101 shown in FIG. 49 is formed of a conductive material having a function of reflecting light, and electrode 2102 is formed of a conductive material having a function of transmitting light and reflecting light, and by forming a micro-optical resonator (microcavity) structure, the light emission obtained from light-emitting layer 2140 or light-emitting layer 2170 can be resonated between both electrodes, and the intensity of light of a desired wavelength among the light emission emitted from electrode 2102 can be enhanced.

[0205] Here, the case of extracting light on the electrode 2102 side (cathode side) is described, but the​​​​​​​​​​ It is also possible to adopt a configuration in which light is extracted from the 2101 side (anode side). In that case, the electrode 2101 is formed of a conductive material having a function of reflecting light and a function of transmitting light, and the electrode 2102 is formed of a conductive material having a function of reflecting light.

[0206] The light emitted from the light-emitting layer 2140 and the light-emitting layer 2170 resonates between a pair of electrodes (for example, the electrode 2101 and the electrode 2102). Further, the light-emitting layer 2140 and the light-emitting layer 2170 are formed at positions where the intensity of light having a desired wavelength among the emitted light is enhanced. For example, by adjusting the optical distance from the reflection region of the electrode 2101 to the light-emitting region of the light-emitting layer 2170 and the optical distance from the reflection region of the electrode 2102 to the light-emitting region of the light-emitting layer 2170, it is possible to enhance the intensity of light having a desired wavelength among the light emitted from the light-emitting layer 2170. Also, by adjusting the optical distance from the reflection region of the electrode 2101 to the light-emitting region of the light-emitting layer 2140 and the optical distance from the reflection region of the electrode 2102 to the light-emitting region of the light-emitting layer 2140, it is possible to enhance the intensity of light having a desired wavelength among the light emitted from the light-emitting layer 2140. That is, in the case of a light-emitting element in which a plurality of light-emitting layers (here, the light-emitting layer 2140 and the light-emitting layer 2170) are stacked, it is preferable to optimize the respective optical distances of the light-emitting layer 2140 and the light-emitting layer 2170. For example, in order to amplify the light having a desired wavelength (wavelength: λ) obtained from the light-emitting layer 2140, the optical distance from the reflection region of the electrode 2101 to the region where the light having the desired wavelength of the light-emitting layer 2140 is obtained (light-emitting region ) and the optical distance from the reflection region of the electrode 2102 to the region where the light having the desired wavelength of the light-emitting layer 2140 is obtained

[0207] and the optical distance from the reflection region of the electrode 2101 to the region (light-emitting region ) where the light having the desired wavelength of the light-emitting layer 2140 is obtained, and the optical distance from the reflection region of the electrode 2102 to the region where the light having the desired wavelength of the light-emitting layer 2140 is obtained ​​The optical distance to the region to be obtained (light-emitting region) and are each adjusted to be in the vicinity of (2m’-1)λ / 4 (where m’ is a natural number), which is preferable. Here, the light-emitting region refers to the recombination region of holes and electrons in the light-emitting layer 2140.

[0208] By performing such optical adjustment, the emission spectrum obtained from the light-emitting layer 2140 can be narrowed and linearized, and light emission with good color purity can be obtained.

[0209] ≪Substrate≫ In addition, the light-emitting element according to one aspect of the present invention may be manufactured on a substrate made of glass, plastic, or the like. As the order of manufacturing on the substrate, they may be laminated in order from the electrode 101 side, or may be laminated in order from the electrode 102 side. In the light-emitting elements 2250a and 2250b, they may be laminated in order from the electrode 2101, electrode 2102, and electrode 2103 sides, or may be laminated in order from the electrode 210 2 side.

[0210] As the substrate on which the light-emitting element according to one aspect of the present invention can be formed, for example, glass, quartz or plastic can be used. A flexible substrate may also be used. A flexible substrate is a substrate that can be bent (flexible), and examples thereof include plastic substrates made of polycarbonate and polyarylate. In addition, a film, an inorganic vapor deposition film, or the like can also be used. As long as it functions as a support in the manufacturing process of the light-emitting element and the optical element, other materials may be used. Alternatively, as long as it has a function of protecting the light-emitting element and the optical element, it may be used.

[0211] ​​​​For example, in the present invention and the like, light-emitting elements can be formed using various substrates. The type of substrate is not particularly limited. As an example of the substrate, a semiconductor substrate (e.g., a single crystal substrate or a silicon substrate), an SOI substrate, a glass substrate, a quartz substrate, a plastic substrate, a stainless steel substrate, a substrate having a stainless steel foil, a tungsten substrate, a substrate having a tungsten foil, a flexible substrate, a laminated film, a fibrous material-containing cellulose nanofiber (CNF) or paper, or a base film and the like. As an example of the glass substrate, there are barium borosilicate glass, aluminoborosilicate glass, or soda-lime glass and the like. Examples of the flexible substrate, the laminated film, the base film, etc. include the following. For example, plastics represented by polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polytetrafluoro ethylene (PTFE). Or, as an example, there are resins such as acrylic. Or, as an example, there are polypropylene, polyester, polyvinyl fluoride, or polyvinyl chloride and the like. Or, as an example, there are polyamide, polyimide, aramid, epoxy, an inorganic vapor deposition film, or papers and the like.

[0212] Also, as the substrate, a flexible substrate can be used, and a light-emitting element can be directly formed on the flexible substrate. Or, a release layer may be provided between the substrate and the light-emitting element. The release layer is used to separate from the substrate after partially or completely completing the light-emitting element thereon and transfer it to another substrate. At that time, the light-emitting element can be transferred to a substrate with poor heat resistance or a flexible substrate. Oh, the above-mentioned release layer may have, for example, a laminated structure of inorganic films such as a tungsten film and a silicon oxide film A structure in which a resin film such as polyimide is formed on a substrate or the like can be used.

[0213] That is, a light-emitting element may be formed using a certain substrate, and then the light-emitting element may be transferred to another substrate and the light-emitting element may be disposed on another substrate. As an example of the substrate to which the light-emitting element is transferred, in addition to the above-described substrate, a cellophane substrate, a stone substrate, a wood substrate, a cloth substrate (including natural fibers (silk, cotton, hemp), synthetic fibers (nylon, polyurethane, polyester) or recycled fibers (acetate, cupra, rayon, recycled polyester), etc.), a leather substrate, or a rubber substrate There is. By using these substrates, a light-emitting element that is not easily broken, a light-emitting element with high heat resistance, a light-emitting element with reduced weight, or a light-emitting element with reduced thickness can be obtained.

[0214] Also, for example, a field effect transistor (FET) may be formed on the above-described substrate, and light-emitting elements 150, 2250a, and 2250 b may be fabricated on an electrode electrically connected to the FET. Thereby, an active matrix type display device that controls the driving of the light-emitting element by the FET can be fabricated.

[0215] Also, as the substrate 2220 on which the optical element is formed, the substrates listed above can be used.

[0216] ≪Light-shielding layer≫ The light-shielding layer 2223 has a function of suppressing the reflection of external light. Or, the light-shielding layer 222 3 has a function of preventing color mixing of light emitted from adjacent light-emitting elements. The light-shielding layer 22 23 includes metals, resins containing black pigments, carbon black, metal oxides, a plurality of golds A composite oxide or the like containing a solid solution of an oxide can be used.

[0217] ≪Optical Element≫ The optical elements 2224B, 2224G, and 2224R have a function of selectively transmitting light having a specific color from the incident light. For example, the light emitted from the region 2222B transmitted through the optical element 2224B becomes light having a blue color, and the light emitted from the region 2222G transmitted through the optical element 2224G becomes light having a green color. And the light emitted from the region 2222R transmitted through the optical element 2224R becomes light having a red color.

[0218] For the optical elements 2224R, 2224G, and 2224B, for example, a coloring layer (also referred to as a color filter), a band-pass filter, a multilayer film filter, or the like can be applied. Further, a color conversion element can be applied to the optical element. The color conversion element is an optical element that converts incident light into light having a wavelength longer than the wavelength of the light. As the color conversion element, an element using quantum dots is preferably used. By using quantum dots, the color reproducibility of the display device can be improved.

[0219] Note that one or more other optical elements may be provided on the optical elements 2224R, 2224G, and 2224B. As the other optical elements, for example, a circular polarizing plate, an antireflection film, or the like can be provided. When a circular polarizing plate is provided on the side from which the light emitted from the light-emitting element of the display device is emitted, it is possible to prevent the phenomenon that the light incident from the outside of the display device is reflected inside the display device and then emitted to the outside. Further, when an antireflection film is provided, ​​​​​​​​​The external light reflected on the surface can be weakened. As a result, the light emitted by the display device can be clearly observed.

[0220] <<Partition wall>> The partition wall 2145 only needs to be insulating and can be formed using an inorganic material or an organic material. Examples of the inorganic material include silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, aluminum oxide, aluminum nitride, and the like. Examples of the organic material include photosensitive resin materials such as acrylic resin or polyimide resin.

[0221] Note that the silicon oxynitride film refers to a film having a higher oxygen content than nitrogen in its composition, preferably, oxygen is 55 atomic% or more and 65 atomic% or less, nitrogen is 1 atomic% or more and 20 atomic% or less, silicon is 25 atomic% or more and 35 atomic% or less, and hydrogen is 0.1 atomic% or more and 10 atomic% or less. The silicon nitride oxide film refers to a film having a higher nitrogen content than oxygen in its composition, preferably, nitrogen is 55 atomic% or more and 65 atomic% or less, oxygen is 1 atomic% or more and 20 atomic% or less, silicon is 25 atomic% or more and 35 atomic% or less, and hydrogen is 0.1 atom % or more and 10 atomic% or less.

[0222] As described above, the configuration shown in the present embodiment can be used in appropriate combination with other embodiments. It can be used.

[0223] (Embodiment 2) In the present embodiment, a light-emitting element having a configuration different from that of the light-emitting element shown in Embodiment 1, and the light-emitting mechanism of the light-emitting element will be described below with reference to FIG. 3. Note that in FIG. 3, for portions having the same functions as the reference numerals shown in FIG. 1(A), the same hatch pattern is used. and sometimes the reference signs may be omitted. Also, parts having the same function are denoted by the same reference signs , and the detailed description thereof may be omitted.

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

[0225] In the light-emitting element 250 and the light-emitting element 252 shown in FIGS. 3(A) and 3(B), between a pair of electrodes (electrodes 101 and 102), there are a plurality of light-emitting units (in FIGS. 3(A) and 3(B), the light-emitting unit 106 and the light-emitting unit 108). Note that, in the light-emitting element 250 and the light-emitting element 252, assuming that the electrode 101 functions as an anode and the electrode 102 functions as a cathode, the following description will be given, but the configuration of the light-emitting element 250 may be reversed.

[0226] Also, in the light-emitting element 250 and the light-emitting element 252 shown in FIGS. 3(A) and 3(B), the light-emitting unit 106 and the light-emitting unit 108 are stacked, and a charge generation layer 115 is provided between the light-emitting unit 106 and the light-emitting unit 108. Note that the light-emitting unit 106 and the light-emitting unit 108 may have the same configuration or different configurations.

[0227] Also, the light-emitting element 250 and the light-emitting element 252 include a light-emitting layer 140 and a light-emitting layer 170. Also, in addition to the light-emitting layer 170, the light-emitting unit 106 includes a hole injection layer 111, a hole transport layer 112, an electron transport layer 113, and an electron injection layer 114. Also, in addition to the light-emitting layer 140, the light-emitting unit 108 includes a hole injection layer 116, a hole transport layer 119, an electron transport layer 118, and an electron injection layer 130.

[0228] The composite material of the organic compound having a transition metal and a non - shared electron pair described in the first embodiment can be preferably used for the electron injection layer 114 and the electron injection layer 130. By adopting such a configuration, a light - emitting element with excellent moisture resistance, good reliability, and low driving voltage can be provided. Also, as in the light - emitting element 252 shown in FIG. 3(B), a charge generation layer 160 may be provided between the electron injection layer 130 and the electrode 102. By adopting such a configuration, an element with even better moisture resistance and acid resistance can be provided. As described above, for the charge generation layer 115 and the charge generation layer 160, the configuration may be such that an acceptor substance, which is an electron acceptor, is added to the hole - transporting material, or a donor substance, which is an electron donor, is added to the electron - transporting material. Also, a configuration in which both of these are laminated may be used. By adopting such a configuration, a light - emitting element with excellent moisture resistance can be easily manufactured. Moreover, in the light - emitting element according to one aspect of the present invention, the charge generation layer 115 and the charge generation layer 160 may be made of the same material respectively. For example, the charge generation layer 115 and the charge generation layer 160 may be made of the same hole - transporting material and the same acceptor material. By adopting such a configuration, it is preferable because a light - emitting element with excellent moisture resistance can be easily manufactured. Note that the charge generation layer 115 sandwiched between the light - emitting unit 106 and the light - emitting unit 108 only needs to inject electrons into one light - emitting unit and holes into the other light - emitting unit when a voltage is applied between the electrode 101 and the electrode 102. For example, in FIGS. 3(A) and (B)

[0229]

[0230]

[0231] ​​​​​​​​​​​​​​A voltage is applied such that the potential of the electrode 101 is higher than the potential of the electrode 102. In this case, the charge generation layer 115 injects electrons into the light-emitting unit 106 and holes into the light-emitting unit 108.

[0232] In addition, in FIGS. 3(A) and (B), the light-emitting device having two light-emitting units has been described, but the present invention can be similarly applied to a light-emitting device in which three or more light-emitting units are stacked. As shown in the light-emitting device 250, by arranging a plurality of light-emitting units between a pair of electrodes with a charge generation layer interposed therebetween, high-brightness light emission can be achieved while keeping the current density low, and a light-emitting device with a longer lifespan can be realized. In addition, a light-emitting device with low power consumption can be realized.

[0233] Note that, in each of the above configurations, the light-emitting colors exhibited by the guest materials used in the light-emitting unit 106 and the light-emitting unit 108 may be the same or different from each other. When the guest materials have a function of emitting light of the same color in the light-emitting unit 106 and the light-emitting unit 108, the light-emitting devices 250 and 252 are preferably light-emitting devices that exhibit high emission luminance at a low current value. When the guest materials have a function of emitting light of different colors in the light-emitting unit 106 and the light-emitting unit 108, the light-emitting device 250 is preferably a light-emitting device that exhibits multi-color light emission. In this case, by using a plurality of light-emitting materials having different emission wavelengths in either one or both of the light-emitting layer 140 and the light-emitting layer 170, the emission spectrum exhibited by the light-emitting device 250 is light in which emissions having different emission peaks are synthesized, and thus the emission spectrum has at least two maxima.

[0234] The above configuration is also suitable for obtaining white light emission. By making the light from the light-emitting layer 140 and the light-emitting layer 170 complementary to each other, white light emission can be obtained. In particular, it is preferable to select a guest material so as to obtain white light emission with high color rendering properties, or light emission having at least red, green, and blue. By making the light from the light-emitting layer 140 and the light-emitting layer 170 complementary to each other, white light emission can be obtained. In particular, it is preferable to select a guest material so as to obtain white light emission with high color rendering properties, or light emission having at least red, green, and blue. By making the light from the light-emitting layer 140 and the light-emitting layer 170 complementary to each other, white light emission can be obtained. In particular, it is preferable to select a guest material so as to obtain white light emission with high color rendering properties, or light emission having at least red, green, and blue. By making the light from the light-emitting layer 140 and the light-emitting layer 170 complementary to each other, white light emission can be obtained. In particular, it is preferable to select a guest material so as to obtain white light emission with high color rendering properties, or light emission having at least red, green, and blue.

[0235] In the case of a light-emitting device in which three or more light-emitting units are stacked, the light-emitting colors exhibited by the guest materials used in the respective light-emitting units may be the same or different from each other. When there are a plurality of light-emitting units exhibiting the same color light emission, the light-emitting colors exhibited by the plurality of light-emitting units can obtain high light-emitting luminance at a low current value as compared with other colors. Such a configuration can be suitably used for adjusting the light-emitting color. In particular, it is suitable when using guest materials having different light-emission efficiencies and exhibiting different light-emitting colors. For example, in the case of having a three-layer light-emitting unit, two layers of light-emitting units having a fluorescent compound of the same color and one layer of a light-emitting unit having a phosphorescent compound exhibiting a light-emitting color different from that of the fluorescent compound can adjust the light-emitting intensities of fluorescence emission and phosphorescence emission. That is, the intensity of the light-emitting color can be adjusted according to the number of light-emitting units. In the case of a light-emitting device in which three or more light-emitting units are stacked, the light-emitting colors exhibited by the guest materials used in the respective light-emitting units may be the same or different from each other. When there are a plurality of light-emitting units exhibiting the same color light emission, the light-emitting colors exhibited by the plurality of light-emitting units can obtain high light-emitting luminance at a low current value as compared with other colors. Such a configuration can be suitably used for adjusting the light-emitting color. In particular, it is suitable when using guest materials having different light-emission efficiencies and exhibiting different light-emitting colors. For example, in the case of having a three-layer light-emitting unit, two layers of light-emitting units having a fluorescent compound of the same color and one layer of a light-emitting unit having a phosphorescent compound exhibiting a light-emitting color different from that of the fluorescent compound can adjust the light-emitting intensities of fluorescence emission and phosphorescence emission. That is, the intensity of the light-emitting color can be adjusted according to the number of light-emitting units. In the case of a light-emitting device in which three or more light-emitting units are stacked, the light-emitting colors exhibited by the guest materials used in the respective light-emitting units may be the same or different from each other. When there are a plurality of light-emitting units exhibiting the same color light emission, the light-emitting colors exhibited by the plurality of light-emitting units can obtain high light-emitting luminance at a low current value as compared with other colors. Such a configuration can be suitably used for adjusting the light-emitting color. In particular, it is suitable when using guest materials having different light-emission efficiencies and exhibiting different light-emitting colors. For example, in the case of having a three-layer light-emitting unit, two layers of light-emitting units having a fluorescent compound of the same color and one layer of a light-emitting unit having a phosphorescent compound exhibiting a light-emitting color different from that of the fluorescent compound can adjust the light-emitting intensities of fluorescence emission and phosphorescence emission. That is, the intensity of the light-emitting color can be adjusted according to the number of light-emitting units. In the case of a light-emitting device in which three or more light-emitting units are stacked, the light-emitting colors exhibited by the guest materials used in the respective light-emitting units may be the same or different from each other. When there are a plurality of light-emitting units exhibiting the same color light emission, the light-emitting colors exhibited by the plurality of light-emitting units can obtain high light-emitting luminance at a low current value as compared with other colors. Such a configuration can be suitably used for adjusting the light-emitting color. In particular, it is suitable when using guest materials having different light-emission efficiencies and exhibiting different light-emitting colors. For example, in the case of having a three-layer light-emitting unit, two layers of light-emitting units having a fluorescent compound of the same color and one layer of a light-emitting unit having a phosphorescent compound exhibiting a light-emitting color different from that of the fluorescent compound can adjust the light-emitting intensities of fluorescence emission and phosphorescence emission. That is, the intensity of the light-emitting color can be adjusted according to the number of light-emitting units. In the case of a light-emitting device in which three or more light-emitting units are stacked, the light-emitting colors exhibited by the guest materials used in the respective light-emitting units may be the same or different from each other. When there are a plurality of light-emitting units exhibiting the same color light emission, the light-emitting colors exhibited by the plurality of light-emitting units can obtain high light-emitting luminance at a low current value as compared with other colors. Such a configuration can be suitably used for adjusting the light-emitting color. In particular, it is suitable when using guest materials having different light-emission efficiencies and exhibiting different light-emitting colors. For example, in the case of having a three-layer light-emitting unit, two layers of light-emitting units having a fluorescent compound of the same color and one layer of a light-emitting unit having a phosphorescent compound exhibiting a light-emitting color different from that of the fluorescent compound can adjust the light-emitting intensities of fluorescence emission and phosphorescence emission. That is, the intensity of the light-emitting color can be adjusted according to the number of light-emitting units. In the case of a light-emitting device in which three or more light-emitting units are stacked, the light-emitting colors exhibited by the guest materials used in the respective light-emitting units may be the same or different from each other. When there are a plurality of light-emitting units exhibiting the same color light emission, the light-emitting colors exhibited by the plurality of light-emitting units can obtain high light-emitting luminance at a low current value as compared with other colors. Such a configuration can be suitably used for adjusting the light-emitting color. In particular, it is suitable when using guest materials having different light-emission efficiencies and exhibiting different light-emitting colors. For example, in the case of having a three-layer light-emitting unit, two layers of light-emitting units having a fluorescent compound of the same color and one layer of a light-emitting unit having a phosphorescent compound exhibiting a light-emitting color different from that of the fluorescent compound can adjust the light-emitting intensities of fluorescence emission and phosphorescence emission. That is, the intensity of the light-emitting color can be adjusted according to the number of light-emitting units. In the case of a light-emitting device in which three or more light-emitting units are stacked, the light-emitting colors exhibited by the guest materials used in the respective light-emitting units may be the same or different from each other. When there are a plurality of light-emitting units exhibiting the same color light emission, the light-emitting colors exhibited by the plurality of light-emitting units can obtain high light-emitting luminance at a low current value as compared with other colors. Such a configuration can be suitably used for adjusting the light-emitting color. In particular, it is suitable when using guest materials having different light-emission efficiencies and exhibiting different light-emitting colors. For example, in the case of having a three-layer light-emitting unit, two layers of light-emitting units having a fluorescent compound of the same color and one layer of a light-emitting unit having a phosphorescent compound exhibiting a light-emitting color different from that of the fluorescent compound can adjust the light-emitting intensities of fluorescence emission and phosphorescence emission. That is, the intensity of the light-emitting color can be adjusted according to the number of light-emitting units. In the case of a light-emitting device in which three or more light-emitting units are stacked, the light-emitting colors exhibited by the guest materials used in the respective light-emitting units may be the same or different from each other. When there are a plurality of light-emitting units exhibiting the same color light emission, the light-emitting colors exhibited by the plurality of light-emitting units can obtain high light-emitting luminance at a low current value as compared with other colors. Such a configuration can be suitably used for adjusting the light-emitting color. In particular, it is suitable when using guest materials having different light-emission efficiencies and exhibiting different light-emitting colors. For example, in the case of having a three-layer light-emitting unit, two layers of light-emitting units having a fluorescent compound of the same color and one layer of a light-emitting unit having a phosphorescent compound exhibiting a light-emitting color different from that of the fluorescent compound can adjust the light-emitting intensities of fluorescence emission and phosphorescence emission. That is, the intensity of the light-emitting color can be adjusted according to the number of light-emitting units. In the case of a light-emitting device in which three or more light-emitting units are stacked, the light-emitting colors exhibited by the guest materials used in the respective light-emitting units may be the same or different from each other. When there are a plurality of light-emitting units exhibiting the same color light emission, the light-emitting colors exhibited by the plurality of light-emitting units can obtain high light-emitting luminance at a low current value as compared with other colors. Such a configuration can be suitably used for adjusting the light-emitting color. In particular, it is suitable when using guest materials having different light-emission efficiencies and exhibiting different light-emitting colors. For example, in the case of having a three-layer light-emitting unit, two layers of light-emitting units having a fluorescent compound of the same color and one layer of a light-emitting unit having a phosphorescent compound exhibiting a light-emitting color different from that of the fluorescent compound can adjust the light-emitting intensities of fluorescence emission and phosphorescence emission. That is, the intensity of the light-emitting color can be adjusted according to the number of light-emitting units. In the case of a light-emitting device in which three or more light-emitting units are stacked, the light-emitting colors exhibited by the guest materials used in the respective light-emitting units may be the same or different from each other. When there are a plurality of light-emitting units exhibiting the same color light emission, the light-emitting colors exhibited by the plurality of light-emitting units can obtain high light-emitting luminance at a low current value as compared with other colors. Such a configuration can be suitably used for adjusting the light-emitting color. In particular, it is suitable when using guest materials having different light-emission efficiencies and exhibiting different light-emitting colors. For example, in the case of having a three-layer light-emitting unit, two layers of light-emitting units having a fluorescent compound of the same color and one layer of a light-emitting unit having a phosphorescent compound exhibiting a light-emitting color different from that of the fluorescent compound can adjust the light-emitting intensities of fluorescence emission and phosphorescence emission. That is, the intensity of the light-emitting color can be adjusted according to the number of light-emitting units.

[0236] In the case of a light-emitting device having two layers of such fluorescence-emitting units and one layer of phosphorescence-emitting units, a light-emitting device containing two layers of light-emitting units containing a blue fluorescent compound and one layer of a light-emitting unit containing a yellow phosphorescent compound, or a light-emitting device having two layers of light-emitting units containing a blue fluorescent compound and one layer of a light-emitting unit layer containing a red phosphorescent compound and a green phosphorescent compound, a light-emitting device containing a blue fluorescent compound In the case of a light-emitting device having two layers of such fluorescence-emitting units and one layer of phosphorescence-emitting units, a light-emitting device containing two layers of light-emitting units containing a blue fluorescent compound and one layer of a light-emitting unit containing a yellow phosphorescent compound, or a light-emitting device having two layers of light-emitting units containing a blue fluorescent compound and one layer of a light-emitting unit layer containing a red phosphorescent compound and a green phosphorescent compound, a light-emitting device containing a blue fluorescent compound In the case of a light-emitting device having two layers of such fluorescence-emitting units and one layer of phosphorescence-emitting units, a light-emitting device containing two layers of light-emitting units containing a blue fluorescent compound and one layer of a light-emitting unit containing a yellow phosphorescent compound, or a light-emitting device having two layers of light-emitting units containing a blue fluorescent compound and one layer of a light-emitting unit layer containing a red phosphorescent compound and a green phosphorescent compound, a light-emitting device containing a blue fluorescent compound In the case of a light-emitting device having two layers of such fluorescence-emitting units and one layer of phosphorescence-emitting units, a light-emitting device containing two layers of light-emitting units containing a blue fluorescent compound and one layer of a light-emitting unit containing a yellow phosphorescent compound, or a light-emitting device having two layers of light-emitting units containing a blue fluorescent compound and one layer of a light-emitting unit layer containing a red phosphorescent compound and a green phosphorescent compound, a light-emitting device containing a blue fluorescent compound A light-emitting unit including a two-layer structure and a red phosphorescent compound, a yellow phosphorescent compound, and a green phosphorescent compound A light-emitting device having a light-emitting layer unit including one layer, and white light emission can be efficiently obtained, which is preferable. Preferably.

[0237] Further, at least one of the light-emitting layer 140 or the light-emitting layer 170 may be further divided into layers, and different light-emitting materials may be contained in each of the divided layers. That is, at least one of the light-emitting layer 14 0, or the light-emitting layer 170 may be composed of two or more layers. For example, when the first light-emitting layer and the second light-emitting layer are laminated in order from the hole transport layer side to form a light-emitting layer In this case, a material having hole transport properties may be used as the host material of the first light-emitting layer, and a material having electron transport properties may be used as the host material of the second light-emitting layer There are configurations such as this. In this case, the light-emitting materials included in the first light-emitting layer and the second light-emitting layer may be the same material or different materials, and may be materials having a function of emitting light of the same color or materials having a function of emitting light of different colors. With a configuration having a plurality of light-emitting materials having functions of emitting light of different colors, white light emission with high color rendering properties composed of the three primary colors or four or more light-emitting colors can be obtained It can also be obtained. Well, it may be a material having a function of emitting light of the same color or a material having a function of emitting light of different colors. A plurality of light-emitting materials having functions of emitting light of different colors from each other By the configuration having, high-color-rendering white light emission composed of the three primary colors or four or more light-emitting colors can be obtained It can also be obtained.

[0238] Note that the light-emitting unit 106, the light-emitting unit 108, and the charge generation layer 115 can be formed by methods such as vapor deposition ( including vacuum vapor deposition), inkjet method, coating method, gravure printing, etc. It can be done.

[0239] Note that the configuration shown in this embodiment can be appropriately combined with the configurations shown in other embodiments and used It can be used.

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

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

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

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

[0244] The source side driver circuit 601 includes an n-channel TFT 623 and a p-channel TFT 624. A CMOS circuit combined with [the above] is formed. Also, the drive circuit may be formed of various CMOS circuits, PMOS circuits, or NMOS circuits. In this embodiment, a driver-integrated type in which the drive circuit is formed on a substrate is shown, but this is not necessarily required, and the drive circuit can also be formed outside the substrate without being formed on the substrate. Also, in this embodiment, a driver-integrated type in which the drive circuit is formed on a substrate is shown, but this is not necessarily required, and the drive circuit can also be formed outside the substrate without being formed on the substrate. Also, in this embodiment, a driver-integrated type in which the drive circuit is formed on a substrate is shown, but this is not necessarily required, and the drive circuit can also be formed outside the substrate without being formed on the substrate. without being formed on the substrate.

[0245] Also, the pixel portion 602 is formed of pixels including a switching TFT 611, a current control TFT 612, and a first electrode 613 electrically connected to the drain thereof. Note that an insulator 614 is formed so as to cover an end portion of the first electrode 613. The insulator 614 can be formed by using a positive photosensitive resin film. Also, the pixel portion 602 is formed of pixels including a switching TFT 611, a current control TFT 612, and a first electrode 613 electrically connected to the drain thereof. Note that an insulator 614 is formed so as to cover an end portion of the first electrode 613. The insulator 614 can be formed by using a positive photosensitive resin film. Also, the pixel portion 602 is formed of pixels including a switching TFT 611, a current control TFT 612, and a first electrode 613 electrically connected to the drain thereof. Note that an insulator 614 is formed so as to cover an end portion of the first electrode 613. The insulator 614 can be formed by using a positive photosensitive resin film. Also, the pixel portion 602 is formed of pixels including a switching TFT 611, a current control TFT 612, and a first electrode 613 electrically connected to the drain thereof. Note that an insulator 614 is formed so as to cover an end portion of the first electrode 613. The insulator 614 can be formed by using a positive photosensitive resin film.

[0246] Also, in order to improve the covering property of the film formed on the insulator 614, a surface having a curvature is formed at the upper end portion or the lower end portion of the insulator 614. For example, when photosensitive acrylic is used as the material of the insulator 614, it is preferable to provide a curved surface only at the upper end portion of the insulator 614. The radius of curvature of the curved surface is preferably 0.2 μm or more and 0.3 μm or less. Also, as the insulator 614, either a negative type or a positive type photosensitive material can be used. Also, in order to improve the covering property of the film formed on the insulator 614, a surface having a curvature is formed at the upper end portion or the lower end portion of the insulator 614. For example, when photosensitive acrylic is used as the material of the insulator 614, it is preferable to provide a curved surface only at the upper end portion of the insulator 614. The radius of curvature of the curved surface is preferably 0.2 μm or more and 0.3 μm or less. Also, as the insulator 614, either a negative type or a positive type photosensitive material can be used. Also, in order to improve the covering property of the film formed on the insulator 614, a surface having a curvature is formed at the upper end portion or the lower end portion of the insulator 614. For example, when photosensitive acrylic is used as the material of the insulator 614, it is preferable to provide a curved surface only at the upper end portion of the insulator 614. The radius of curvature of the curved surface is preferably 0.2 μm or more and 0.3 μm or less. Also, as the insulator 614, either a negative type or a positive type photosensitive material can be used. Also, in order to improve the covering property of the film formed on the insulator 614, a surface having a curvature is formed at the upper end portion or the lower end portion of the insulator 614. For example, when photosensitive acrylic is used as the material of the insulator 614, it is preferable to provide a curved surface only at the upper end portion of the insulator 614. The radius of curvature of the curved surface is preferably 0.2 μm or more and 0.3 μm or less. Also, as the insulator 614, either a negative type or a positive type photosensitive material can be used. Also, in order to improve the covering property of the film formed on the insulator 614, a surface having a curvature is formed at the upper end portion or the lower end portion of the insulator 614. For example, when photosensitive acrylic is used as the material of the insulator 614, it is preferable to provide a curved surface only at the upper end portion of the insulator 614. The radius of curvature of the curved surface is preferably 0.2 μm or more and 0.3 μm or less. Also, as the insulator 614, either a negative type or a positive type photosensitive material can be used.

[0247] An EL layer 616 and a second electrode 617 are respectively formed on the first electrode 613. Here, as the material used for the first electrode 613 that functions as an anode, it is desirable to use a material having a large work function. For example, in addition to single-layer films such as an ITO film, an indium tin oxide film containing silicon, an indium oxide film containing 2 wt% or more and 20 wt% or less of zinc oxide, a titanium nitride film, a chromium film, a tungsten film, a Zn film, and a Pt film, a titanium nitride and An EL layer 616 and a second electrode 617 are respectively formed on the first electrode 613. Here, as the material used for the first electrode 613 that functions as an anode, it is desirable to use a material having a large work function. For example, in addition to single-layer films such as an ITO film, an indium tin oxide film containing silicon, an indium oxide film containing 2 wt% or more and 20 wt% or less of zinc oxide, a titanium nitride film, a chromium film, a tungsten film, a Zn film, and a Pt film, a titanium nitride and An EL layer 616 and a second electrode 617 are respectively formed on the first electrode 613. Here, as the material used for the first electrode 613 that functions as an anode, it is desirable to use a material having a large work function. For example, in addition to single-layer films such as an ITO film, an indium tin oxide film containing silicon, an indium oxide film containing 2 wt% or more and 20 wt% or less of zinc oxide, a titanium nitride film, a chromium film, a tungsten film, a Zn film, and a Pt film, a titanium nitride and An EL layer 616 and a second electrode 617 are respectively formed on the first electrode 613. Here, as the material used for the first electrode 613 that functions as an anode, it is desirable to use a material having a large work function. For example, in addition to single-layer films such as an ITO film, an indium tin oxide film containing silicon, an indium oxide film containing 2 wt% or more and 20 wt% or less of zinc oxide, a titanium nitride film, a chromium film, a tungsten film, a Zn film, and a Pt film, a titanium nitride and An EL layer 616 and a second electrode 617 are respectively formed on the first electrode 613. Here, as the material used for the first electrode 613 that functions as an anode, it is desirable to use a material having a large work function. For example, in addition to single-layer films such as an ITO film, an indium tin oxide film containing silicon, an indium oxide film containing 2 wt% or more and 20 wt% or less of zinc oxide, a titanium nitride film, a chromium film, a tungsten film, a Zn film, and a Pt film, a titanium nitride and Lamination with a film mainly composed of aluminum, a titanium nitride film and a film mainly composed of aluminum A three-layer structure or the like of a titanium nitride film and a titanium nitride film can be used. When a laminated structure is used, the resistance as a wiring is also low, good ohmic contact can be achieved, and it can further function as an anode can be achieved.

[0248] In addition, the EL layer 616 is formed by various methods such as vapor deposition using a vapor deposition mask, an inkjet method, and a spin coating method etc. As the material constituting the EL layer 616, a low molecular compound or a high molecular compound (including oligomers and dendrimers) may be used.

[0249] Furthermore, as the material used for the second electrode 617 formed on the EL layer 616 and functioning as a cathode it is preferable to use a material with a small work function (such as Al). When the light generated in the EL layer 61 6 passes through the second electrode 617, as the second electrode 617, the film thickness is a thin metal thin film, and a transparent conductive film (ITO, indium oxide containing 2 wt% or more and 20 wt% or less of zinc oxide indium tin oxide containing silicon, zinc oxide (ZnO), etc.) is preferably used.

[0250] Note that the light-emitting element 618 is formed by the first electrode 613, the EL layer 616, and the second electrode 617 is preferably a light-emitting element having the configurations of Embodiment 1 and Embodiment 2. Note that although a plurality of light-emitting elements are formed in the pixel portion, in the light-emitting device of this embodiment both a light-emitting element having the configuration described in Embodiment 1 and Embodiment 2 and a light-emitting element having other configurations may be included. In the light-emitting device of this embodiment, both a light-emitting element having the configuration described in Embodiment 1 and Embodiment 2 and a light-emitting element having other configurations may be included. Element and a light-emitting element having other configurations may be included.

[0251] Furthermore, by bonding the sealing substrate 604 to the element substrate 610 with the sealing material 605, an element substrate 610, a sealing substrate 604, and a light-emitting element are provided in a space 607 surrounded by the sealing material 605 618. The space 607 is filled with a filling material, and in addition to the case where an inert gas (such as nitrogen or argon) is filled, it may be filled with a resin or a desiccant or both.

[0252] Note that it is preferable to use an epoxy resin or glass frit for the sealing material 605. Also, these materials are desirably materials that do not permeate moisture and oxygen as much as possible. Further, as materials for the sealing substrate 604, in addition to a glass substrate and a quartz substrate, FRP (Fiber R einforced Plastics), PVF (polyvinyl fluoride), polyester or a plastic substrate made of acrylic or the like can be used.

[0253] As described above, a light-emitting device using the light-emitting element described in Embodiment 1 and Embodiment 2 can be obtained.

[0254] <Configuration Example 1 of Light-Emitting Device> FIG. 5 shows an example of a light-emitting device in which a light-emitting element exhibiting white light emission is formed and a colored layer (color f ilter) is formed.

[0255] In FIG. 5(A), a substrate 1001, an underlying insulating film 1002, a gate insulating film 1003, gate electrodes 1006, 1007, 1008, a first interlayer insulating film 1020, a second interlayer insulating film 1021 , a peripheral portion 1042, a pixel portion 1040, a drive circuit portion 1041, first electrodes 102 4W, 1024R, 1024G, 1024B of the light-emitting element, a partition wall 1026, an EL layer 1028, the light-emitting element The second electrode 1029, the sealing substrate 1031, the sealing material 1032, etc. are shown in the figure.

[0256] Also, in FIGS. 5(A) and 5(B), a colored layer (red colored layer 1034R, green colored layer 10 34G, blue colored layer 1034B) is provided on the transparent substrate 1033. Also, a black layer ( black matrix) 1035 may be further provided. The transparent substrate 1033 provided with the colored layer and the black layer is aligned and fixed to the substrate 1001. Note that the colored layer and the black colored layer are covered with an overcoat layer 1036. Also, in FIG. 5(A), there are a light-emitting layer that emits light to the outside without passing through the colored layer and a light-emitting layer that emits light to the outside through each colored layer. The light that does not pass through the colored layer is white, and the light that passes through the colored layer is red, blue, or green. Thus, an image can be expressed with four-color pixels.

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

[0258] Also, in the light-emitting device described above, a light-emitting device having a structure (bottom emission type) that emits light from the side of the substrate 1001 on which the TFT is formed is used. However, a light-emitting device having a structure (top emission type) that emits light from the side of the sealing substrate 1031 may also be used.

[0259] <Configuration Example 2 of Light-Emitting Device> A cross-sectional view of a top emission type light-emitting device is shown in FIG. 6. In this case, as the substrate 1001, a substrate that does not transmit light can be used. A connection electrode that connects the TFT and the anode of the light-emitting element is formed. ​​​​​​ Until it is manufactured, it is formed in the same manner as a bottom emission type light emitting device. After that, the third interlayer insulating film 1037 is formed so as to cover the electrode 1022. This insulating film may serve as a planarization layer. The third interlayer insulating film 1037 can be formed using the same material as the second interlayer insulating film 1021, or various other materials.

[0260] The first lower electrodes 1025W, 1025R, 1025G, 1025B of the light emitting element are anodes here, but they may also be cathodes. Also, in the case of a top emission type light emitting device as shown in FIG. 6, the lower electrodes 1025W, 1025R, 1025G, 1025B are preferably reflective electrodes. Note that the second electrode 1029 preferably has a function of reflecting light and a function of transmitting light. Further, it is preferable that a microcavity structure is applied between the second electrode 1029 and the lower electrodes 1025W, 1025 R, 1025G, 1025B to have a function of amplifying light of a specific wavelength. The configuration of the EL layer 1028 is the same as the configuration described in Embodiment 2, and an element structure capable of obtaining white light emission is adopted. In FIGS. 5(A), 5(B), and 6, as the configuration of the EL layer that can obtain white light emission, it may be realized by using a plurality of light emitting layers or using a plurality of light emitting units.

[0261] Note that the configuration for obtaining white light emission is not limited to these. In the top emission structure as shown in FIG. 6, sealing can be performed with a sealing substrate 1031 provided with coloring layers (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B). The sealing substrate 1031 has a black layer (black matrix) located between pixels.

[0262] located between pixels. A Rix) 1030 may be provided. The coloring layer (red coloring layer 1034R, green coloring layer 1 034G, blue coloring layer 1034B) and the black layer (black matrix) may be covered by an overcoat layer. Note that the sealing substrate 1031 uses a substrate having translucency .

[0263] Also, here, an example of full-color display using four colors of red, green, blue, and white has been shown, but it is not particularly limited , and full-color display may be performed using three colors of red, green, and blue. Also, full-color display may be performed using four colors of red, green, blue, and yellow .

[0264] As described above, a light-emitting device using the light-emitting element described in Embodiment 1 and Embodiment 2 can be obtained.

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

[0266] (Embodiment 4) In this embodiment, a transistor that can be used in a display device according to one aspect of the present invention will be described with reference to FIG. 7.

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

[0268] ​In addition, the transistor shown in Fig. 7(A) has a pair of impurity semiconductor layers 435 that function as a source region and a drain region. The impurity semiconductor layers 435 are provided between the semiconductor layer 432 and the conductive layer 433a, and between the semiconductor layer 432 and the conductive layer 433b. The semiconductor layer 432 and the impurity semiconductor layer 435 are provided in contact with each other, and the impurity semiconductor layer 435 and the conductive layer 43 3a or the conductive layer 433b are provided in contact with each other.

[0269] For the semiconductor layer 432, for example, a semiconductor containing silicon can be used. Examples of the semiconductor containing silicon include hydrogenated amorphous silicon, microcrystalline silicon, or polycrystalline silicon. In particular, using hydrogenated amorphous silicon is preferred because it can be formed with good yield on a large-sized substrate. The display device according to an aspect of the present invention can provide good display even with a transistor to which amorphous silicon having a relatively low field-effect mobility is applied.

[0270] In addition, an organic substance can also be used for the semiconductor layer 432. Examples of the organic substance include the above-mentioned electron transport material and hole transport material. In addition, polymer compounds such as polythiophene, poly-paraphenylene vinylene, and polydiacetylene can also be used. Note that the organic substance is not limited to this.

[0271] The impurity semiconductor film constituting the impurity semiconductor layer 435 is formed of a semiconductor doped with an impurity element that imparts a single conductivity type. When the transistor is an n-channel type, examples of the semiconductor doped with an impurity element that imparts a single conductivity type include silicon doped with P or As. It can be cited. Or, when the transistor is of p-channel type, an impurity of one conductivity type is added. As the impurity element, for example, B can be added, but the transistor is preferably of n-channel type. Note that the impurity semiconductor layer may be formed of an amorphous semiconductor. Or, it may be formed of a crystalline semiconductor such as a microcrystalline semiconductor. Note that the impurity semiconductor layer 43 5 can preferably use the composite material composed of the transition metal and the organic compound having a non-bonding electron pair shown in Embodiment 1.

[0272] The transistor shown in FIG. 7(B) has a semiconductor layer 437 between the semiconductor layer 432 and the impurity semiconductor layer 435.

[0273] The semiconductor layer 437 may be formed of the same semiconductor film as the semiconductor layer 432. The semiconductor layer 437 can function as an etching stopper for preventing the semiconductor layer 432 from disappearing due to etching during the etching of the impurity semiconductor layer 435. In FIG. 7(A), an example in which the semiconductor layer 437 is separated left and right is shown, but a part of the semiconductor layer 437 may cover the channel formation region of the semiconductor layer 432.

[0274] Also, the semiconductor layer 437 may contain an impurity at a lower concentration than the impurity semiconductor layer 435. Thereby, the semiconductor layer 437 can function as an LDD (Lightly Doped Drain) region, and hot carrier degradation when driving the transistor can be suppressed.

[0275] The transistor shown in FIG. 7(C) has an insulating layer 48 on the channel formation region of the semiconductor layer 432. 4 is provided. The insulating layer 484 functions as an etching stopper during the etching of the impurity semiconductor layer 435.

[0276] The transistor shown in FIG. 7(D) has a semiconductor layer 432p instead of the semiconductor layer 432. The semiconductor layer 432p includes a highly crystalline semiconductor film. For example, the semiconductor layer 432p includes a polycrystalline semiconductor or a single crystal semiconductor. Thereby, a transistor with high field-effect mobility can be achieved.

[0277] The transistor shown in FIG. 7(E) has a semiconductor layer 432p in the channel formation region of the semiconductor layer 432. For example, the transistor shown in FIG. 7(E) can be formed by locally crystallizing by irradiating a semiconductor film to be the semiconductor layer 432 with a laser beam or the like. Thereby, a transistor with high field-effect mobility can be realized.

[0278] The transistor shown in FIG. 7(F) has a crystalline semiconductor layer 432p in the channel formation region of the semiconductor layer 432 of the transistor shown in FIG. 7(B).

[0279] The transistor shown in FIG. 7(G) has a crystalline semiconductor layer 432p in the channel formation region of the semiconductor layer 432 of the transistor shown in FIG. 7(C).

[0280] Hereinafter, the components included in the transistor will be described in detail.

[0281] The transistor has a conductive layer that functions as a gate electrode, a semiconductor layer, a conductive layer that functions as a source electrode, a conductive layer that functions as a drain electrode, and an insulating layer that functions as a gate insulating layer.

[0282] Note that the structure of the transistor included in the display device according to one aspect of the present invention is not particularly limited. For example it may be a planar transistor, a staggered transistor, or an inverse staggered transistor. Also, it may have any transistor structure of top gate type or bottom gate type . Alternatively, gate electrodes may be provided above and below the channel .

[0283] The crystallinity of the semiconductor material used for the transistor is also not particularly limited, and any of amorphous semiconductors, semiconductors having crystallinity (microcrystalline semiconductors, polycrystalline semiconductors, single crystal semiconductors, or semiconductors having a crystal region in part) may be used. Using a semiconductor having crystallinity is preferable because deterioration of transistor characteristics can be suppressed . For the semiconductor in which the channel of the transistor is formed, for example, silicon can be used . Particularly, it is preferable to use amorphous silicon. By using amorphous silicon, transistors can be formed with good yield on a large-sized substrate, and mass productivity is excellent

[0284] . Also, crystalline silicon such as microcrystalline silicon, polycrystalline silicon, and single crystal silicon can be used. Particularly, polycrystalline silicon can be formed at a lower temperature than single crystal silicon and has higher field effect mobility and higher reliability than amorphous silicon .

[0285] The transistor having the bottom gate structure exemplified in this embodiment is preferable because the manufacturing process can be reduced . Also, by using amorphous silicon at this time, it is lower than polycrystalline silicon

[0286] ​​​​Since it can be formed at a low temperature, materials with low heat resistance can be used for the wiring and electrodes in the layer below the semiconductor layer and the substrate material, thus widening the range of material selection. For example extremely large glass substrates can be preferably used. On the other hand, top-gate type transistors are preferable because they can easily form impurity regions self-alignedly, thus reducing variations in characteristics and the like. At this time, in particular, it may be suitable when using polycrystalline silicon, single-crystalline silicon and the like.

[0287] ≪Substrate≫ There are no major restrictions on the material of the substrate 411, but it is necessary to have at least heat resistance sufficient to withstand subsequent heat treatment . For example, a glass substrate, a ceramic substrate, a quartz substrate, a sapphire substrate, etc. may be used as the substrate 411. Also, single-crystalline semiconductor substrates, polycrystalline semiconductor substrates made of silicon or silicon carbide , compound semiconductor substrates such as silicon germanium, SOI substrates, etc. can also be applied, and those with semiconductor elements provided on these substrates may be used as the substrate 411. When using a glass substrate as the substrate 411 , by using large-area substrates such as the 6th generation (1500 mm × 1850 mm), 7th generation (1870 mm × 220 0 mm), 8th generation (2200 mm × 2400 mm), 9th generation (2400 mm × 280 0 mm), 10th generation (2950 mm × 3400 mm), etc , a large display device can be manufactured. Using such a large-area substrate is preferable because it can reduce the manufacturing cost .

[0288] Also, as the substrate 411, a flexible substrate is used, and the above transistor is directly formed on the flexible substrate It may be formed. Alternatively, a release layer may be provided between the substrate 411 and the transistor. . After partially or completely forming a transistor on the release layer, it can be separated from the substrate 411 and used for transfer to another substrate. At this time, the transistor can also be transferred to a substrate with inferior heat resistance or a flexible substrate.

[0289] ≪Conductive layer≫ Materials that can be used for the gate, source, and drain of a transistor include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, or tungsten, or alloys having these as the main component, etc. can be cited. Also, a film containing these materials can be used as a single layer or in a laminated structure. For example, a single-layer structure of an aluminum film containing silicon, a two-layer structure in which an aluminum film is laminated on a titanium film, a two-layer structure in which an aluminum film is laminated on a tungsten film, a two-layer structure in which a copper film is laminated on a copper-magnesium-aluminum alloy film, a two-layer structure in which a copper film is laminated on a titanium film, a two-layer structure in which a copper film is laminated on a tungsten film, a three-layer structure in which a titanium film or a titanium nitride film and, on top of that, an aluminum film or a copper film are laminated, and further on top of that, a titanium film or a titanium nitride film is formed, a three-layer structure in which a molybdenum film or a molybdenum nitride film and, on top of that, an aluminum film or a copper film are laminated, and further on top of that, a molybdenum film or a molybdenum nitride film is formed, etc. In addition, oxides such as indium oxide, tin oxide, or zinc oxide may be used. Also, using copper containing manganese is preferable because it enhances the controllability of the shape by etching.

[0290] In addition, conductive materials that can be used for the gate, source, and drain of a transistor and have translucency include conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide , zinc oxide, zinc oxide added with gallium, or graphene. Alternatively, metal materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium , molybdenum, iron, cobalt, copper, palladium, or titanium, or alloy materials containing the metal materials can be used. Alternatively, nitrides of the metal materials (for example, titanium nitride ) can also be used. When using metal materials, alloy materials (or their nitrides), they may be made thin enough to have translucency. In addition, a laminated film of the above materials can be used as a conductive layer . For example, a laminated film of an alloy of silver and magnesium and indium tin oxide is preferably used because it can enhance conductivity. These can also be used for conductive layers such as various wirings and electrodes constituting a display device and conductive layers of display elements (conductive layers functioning as pixel electrodes and common electrodes).

[0291] ≪Insulating Layer≫ As insulating materials that can be used for each insulating layer, for example, resins such as acrylic and epoxy , resins having a siloxane bond such as silicone, and inorganic insulating materials such as silicon oxide, silicon oxynitride , silicon nitride oxynitride, silicon nitride, and aluminum oxide can also be used.

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

[0293] Note that various films such as the conductive film, insulating film, and semiconductor film included in the transistor shown in this embodiment can be formed using a sputtering method, a chemical vapor deposition (CVD) method, a plasma chemical vapor deposition (PECVD), a vacuum evaporation method, a pulsed laser deposition (PLD) method. However, the present invention is not limited thereto, and for example, a coating method, a printing method, a thermal CVD (Chemical Vapor Deposition) method, or an atomic layer deposition (ALD: Atomic Layer Deposition) method may be used. As an example of the thermal CVD method, a conductive film, an insulating film, a semiconductor film, etc. may be formed using MOCVD (Metal Organic Chemical Vapor Deposition) method or the like. ion) method.

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

[0295] Since one aspect of the present invention is a light-emitting element using an organic EL, an electronic device having a flat surface and good luminous efficiency and high reliability can be manufactured. Further, according to one aspect of the present invention, an electronic device having a curved surface and good luminous efficiency and high reliability can be manufactured.

[0296] Examples of the electronic device include a television device, a desktop or notebook personal computer, a monitor for a computer, a digital camera, a digital video camera, a digital photo frame, a mobile phone, a portable game machine, a portable information terminal, an audio reproduction device, a large game machine such as a pachinko machine, and the like.

[0297] The mobile information terminal 900 shown in FIGS. 8(A) and 8(B) includes a housing 901, a housing 902, a display unit 90 3, and a hinge portion 905 and the like.

[0298] The housing 901 and the housing 902 are connected by a hinge portion 905. The mobile information terminal 900 can be unfolded from the folded state (FIG. 8(A)) as shown in FIG. 8(B). Thereby, it has excellent portability when carried, and excellent visibility due to a large display area when used.

[0299] A flexible display unit 903 is provided across the housing 901 and the housing 902 connected by the hinge portion 905 in the mobile information terminal 900.

[0300] A light-emitting device manufactured using one aspect of the present invention can be used for the display unit 903. This makes it possible to manufacture a mobile information terminal with a high yield.

[0301] The display unit 903 can display at least one of document information, still images, moving images, and the like. When displaying document information on the display unit, the mobile information terminal 900 can be used as an e-book terminal.

[0302] When the mobile information terminal 900 is unfolded, the display unit 903 is held in a largely curved form. For example, the display unit 903 is held including a portion curved with a curvature radius of 1 mm or more and 50 mm or less, preferably 5 mm or more and 30 mm or less. A part of the display unit 903 has pixels continuously arranged from the housing 901 to the housing 902 and can perform a curved surface display.

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

[0304] The display unit 903 is preferably composed of a single flexible display. This makes it possible to perform continuous display without interruption between the housing 901 and the housing 902. Note that, a configuration in which a display is provided on each of the housing 901 and the housing 902 may also be adopted.

[0305] The hinge portion 905 preferably has a locking mechanism so that when the portable information terminal 900 is unfolded, the angle between the housing 901 and the housing 902 does not become larger than a predetermined angle. For example, the angle at which the lock is applied (it cannot be opened further) is preferably 90 degrees or more and less than 180 degrees, and typically, it can be 90 degrees, 120 degrees, 135 degrees, 150 degrees, or 17 5 degrees, etc. This can enhance the convenience, safety, and reliability of the portable information terminal 900.

[0306] When the hinge portion 905 has a locking mechanism, it is possible to prevent the display unit 903 from being damaged without applying excessive force to the display unit 903. Therefore, a highly reliable portable information terminal can be realized.

[0307] The housing 901 and the housing 902 may have a power button, operation buttons, an external connection port, a speaker, a microphone, etc.

[0308] A wireless communication module is provided in either one of the housing 901 or the housing 902, and it is possible to transmit and receive data via a computer network such as the Internet, a LAN (Local Area Network), or Wi-Fi (registered trademark ).

[0309] The mobile information terminal 910 shown in Fig. 8(C) includes a housing 911, a display unit 912, operation buttons 913 , an external connection port 914, a speaker 915, a microphone 916, a camera 917, etc.

[0310] The light-emitting device manufactured using one aspect of the present invention can be used for the display unit 912. By doing so, a mobile information terminal can be manufactured with high yield.

[0311] The mobile information terminal 910 is provided with a touch sensor on the display unit 912. Any operation such as making a phone call or inputting text can be performed by touching the display unit 912 with a finger or a stylus.

[0312] Also, by operating the operation buttons 913, it is possible to turn the power on and off and switch the type of image displayed on the display unit 912. For example, it is possible to switch from the mail creation screen to the main menu screen.

[0313] In addition, by providing a detection device such as a gyro sensor or an acceleration sensor inside the mobile information terminal 910, it is possible to determine the orientation (vertical or horizontal) of the mobile information terminal 910 and automatically switch the display orientation of the screen of the display unit 912. Also, the switching of the screen display orientation can be performed by touching the display unit 912, operating the operation buttons 913, or voice input using the microphone 916.

[0314] The mobile information terminal 910 has one or more functions selected from, for example, a telephone, a notebook, or an information browsing device. Specifically, it can be used as a smartphone. The mobile information terminal 910 can be used for, for example, mobile phones, e-mails, text browsing and creation, music It is possible to execute various applications such as reproduction, Internet communication, and games. It can.

[0315] The camera 920 shown in FIG. 8(D) includes a housing 921, a display unit 922, operation buttons 923, a shutter button 924, and the like. The camera 920 also has a detachable lens 926 attached thereto. It is attached. It is.

[0316] The light-emitting device manufactured using one aspect of the present invention can be used for the display unit 922. As a result, a camera with low power consumption can be manufactured. It is possible to manufacture a camera with low power consumption.

[0317] Here, the camera 920 is configured such that the lens 926 can be removed from the housing 921 and replaced, but the lens 926 and the housing 921 may be integrated. It may be integrated.

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

[0319] In addition, the camera 920 can be separately equipped with a strobe device, a viewfinder, etc. Or, these may be incorporated in the housing 921. Or, these may be incorporated in the housing 921.

[0320] FIG. 9(A) shows a wristwatch-type portable information terminal 9200, and FIG. 9(B) shows a wristwatch-type portable information terminal 9201, each being a perspective view. It is.

[0321] The portable information terminal 9200 shown in FIG. 9(A) can execute various applications such as a mobile phone, e-mail, text viewing and creation, music reproduction, Internet communication, and computer games. It can execute various applications such as a mobile phone, e-mail, text viewing and creation, music reproduction, Internet communication, and computer games. It can be performed. Further, the display unit 9001 has its display surface provided in a curved shape, and can perform display along the curved display surface. Further, the portable information terminal 9200 can execute short-range wireless communication conforming to a communication standard For example, it can also make a hands-free call by communicating with a wireless communication-capable headset. Further, the portable information terminal 9 200 has a connection terminal 9006 and can directly exchange data with other information terminals via a connector. It can also be charged via the connection terminal 9006. In addition, charging operation may be performed by wireless power supply without using the connection terminal 9006.

[0322] The portable information terminal 9201 shown in FIG. 9(B) is different from the portable information terminal shown in FIG. 9(A), and the display surface of the display unit 9001 is not curved. Further, the outer shape of the display unit of the portable information terminal 9201 is non-rectangular (circular in FIG. 9(B)).

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

[0324] The portable information terminal 9202 has excellent portability in the folded state and excellent display comprehensibility due to a wide display area without joints in the unfolded state. The display unit 9001 possessed by the portable information terminal 9202 is supported by three housings 9000 connected by a hinge 9055. By bending between two housings 9000 via a hinge 9055, the portable information terminal 9 202 can be reversibly deformed from the deployed state to the folded state. For example , the portable information terminal 9202 can be bent with a radius of curvature of 1 mm or more and 150 mm or less.

[0325] This embodiment can be appropriately combined with other embodiments.

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

[0327] By fabricating a light-emitting element of one aspect of the present invention on a flexible substrate, an electronic device and a lighting device having a curved light-emitting region can be realized.

[0328] In addition, a light-emitting device to which a light-emitting element of one aspect of the present invention is applied can also be applied to vehicle lighting , and for example, lighting can also be installed on the windshield, ceiling, etc.

[0329] FIG. 10(A) shows a perspective view of one side of the multifunctional terminal 3500, and FIG. 10(B) shows a perspective view of the other side of the multifunctional terminal 3500. The multifunctional terminal 3500 has a housing 350 2 in which a display unit 3504, a camera 3506, a lighting 3508, etc. are incorporated. A light-emitting device of one aspect of the present invention can be used for the lighting 3508.

[0330] By using a light-emitting device of one aspect of the present invention, the lighting 3508 functions as a surface light source. ​​Therefore, unlike point light sources typified by LEDs, light emission with less directivity can be obtained. For example, when the illumination 3508 and the camera 3506 are used in combination, the illumination 3508 can be turned on or blinked and imaged by the camera 3506. Since the illumination 3508 has a function as a surface light source, it is possible to take a photograph as if taken under natural light.

[0331] Note that the multifunctional terminal 3500 shown in FIGS. 10(A) and (B) can have various functions similar to the electronic device shown in FIGS. 9(A) to 9(C).

[0332] Also, inside the housing 3502, there can be a speaker, a sensor (for measuring force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared rays), a microphone, etc. Further, by providing a detection device having a sensor for detecting the inclination such as a gyro or an acceleration sensor inside the multifunctional terminal 3500, the direction (portrait or landscape) of the multifunctional terminal 3500 can be determined, and the screen display of the display unit 3504 can be automatically switched.

[0333] The display unit 3504 can also function as an image sensor. For example, by touching the display unit 3 504 with a palm or a finger and imaging a palm print, a fingerprint, etc., personal authentication can be performed. Also, if a backlight that emits near-infrared light or a light source for a sensor that emits near-infrared light is used for the display unit 3504, it is also possible to image finger veins, palm veins, etc. Note that the light-emitting device according to an aspect of the present invention may be applied to the display unit 3504. ​

[0334] Figure 10(C) shows a perspective view of a security light 3600. The light 3600 has illumination 3608 on the outside of the housing 3602, and components such as a speaker 3610 are incorporated into the housing 3602. A light-emitting element according to one aspect of the present invention can be used for the illumination 3608. The light 3600 can emit light, for example, by being grasped, held, or gripped. Also, an electronic circuit capable of controlling the light-emitting method from the light 3600 may be provided inside the housing 3602. The electronic circuit may be, for example, a circuit capable of emitting light once or intermittently multiple times, or a circuit capable of adjusting the light amount of the emitted light by controlling the current value of the emission. Further, a circuit may be incorporated such that a loud alarm sound is output from the speaker 3610 simultaneously with the emission of the illumination 3608. Since the light 3600 can emit light in all directions, it can intimidate, for example, a thug or the like with light or light and sound. Also, the light 3600 may be provided with a function such as a camera, for example, a digital still camera, having a photographing function.

[0335] As the light 3600, for example, it can emit light by being grasped, held, or gripped. Also, inside the housing 3602, an electronic circuit capable of controlling the light-emitting method from the light 3600 may be provided. As the electronic circuit, for example, it may be a circuit capable of emitting light once or intermittently multiple times, or a circuit capable of adjusting the light amount of the emitted light by controlling the current value of the emission. Also, a circuit may be incorporated such that a loud alarm sound is output from the speaker 3610 simultaneously with the emission of the illumination 3608. Since the light 3600 can emit light in all directions, it can intimidate, for example, a thug or the like with light or light and sound. Also, the light 3600 may be provided with a function such as a camera, for example, a digital still camera, having a photographing function.

[0336] As the light 3600, since it can emit light in all directions, it can intimidate, for example, a thug or the like with light or light and sound. Also, the light 3600 may be provided with a function such as a camera, for example, a digital still camera, having a photographing function.

[0337] Figure 11 shows an example in which the light-emitting element is used as an indoor lighting device 8501. Since the light-emitting element can also be made larger in area, a large-area lighting device can also be formed. In addition, by using a housing having a curved surface, a lighting device 8502 having a curved light-emitting area can also be formed. The light-emitting element shown in the present embodiment is in a thin film shape, and the degree of freedom in the design of the housing is high. Therefore, lighting devices with various designs can be formed. Further, for indoor The light-emitting element shown in the present embodiment is in a thin film shape, and the degree of freedom in the design of the housing is high. Therefore, lighting devices with various designs can be formed. Further, for indoor ​​​A large lighting device 8503 may be provided on the wall. A touch sensor may be provided in 503 to turn the power on or off.

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

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

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

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

[0342] [ka]

[0343] [Table 4]

[0344] In addition, the LUMO level of the organic compound used for the electron injection layer 130 of the light-emitting element 2 to the light-emitting element 4 was calculated by cyclic voltammetry (CV) measurement.

[0345] As the measuring device, an electrochemical analyzer (manufactured by BAS Inc., model number: ALS model 600A or 600C) was used. The solution in the CV measurement was dehydrated dimethyl formamide (DMF) (manufactured by Aldrich Co., Ltd., 99.8%, catalog number: 227 05-6) as the solvent, and tetra-n-butylammonium perchlorate (n-B u4NClO4) (manufactured by Tokyo Chemical Industry Co., Ltd., catalog number: T0836) as the supporting electrolyte was dissolved to a concentration of 100 mmol / L, and the measurement target was further dissolved to a concentration of 2 mmol / L to prepare. As the working electrode, a platinum electrode (manufactured by BAS Inc., PT E platinum electrode) was used, as the auxiliary electrode, a platinum electrode (manufactured by BAS Inc., VC-3 used P t counter electrode (5 cm)) was used, and as the reference electrode, an Ag / Ag + electrode (manufactured by BAS Inc., RE7 non-aqueous solvent-based reference electrode) was used respectively. The measurement was performed at room temperature (20 °C or higher and 25 °C or lower). In addition, the scan rate during the CV measurement was unified to 0.1 V / sec, and the oxidation potential Ea [V] and reduction potential Ec [V] with respect to the reference electrode were measured. Ea was defined as the intermediate potential of the oxidation-reduction wave, and Ec was defined as the intermediate potential of the reduction-oxidation wave. Here, the potential energy of the reference electrode used in this example with respect to the vacuum level is known to be -4.94 [eV] Therefore, HOMO level [eV] = -4.94 - Ea, LUMO level ​​​From the equation [eV]=-4.94-Ec, the HOMO level and the LUMO level can be obtained respectively.

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

[0347] <Fabrication of Light-Emitting Device> The fabrication method of the light-emitting device fabricated in this example is shown below. Comparative light-emitting device 1 is a light-emitting device using LiF, which is a Li compound commonly used in the electron injection layer. Light-emitting devices 2 to 4 are light-emitting devices using a composite material of an organic compound having a lone pair of electrons and a transition metal in the electron injection layer, which is one aspect of the present invention.

[0348] ≪Fabrication of Comparative Light-Emitting Device 1≫ On the substrate 210, as the electrode 101, an ITSO film was formed to a thickness of 70 nm. . The electrode area of the electrode 101 was 4 mm 2 (2 mm × 2 mm).

[0349] Next, as the hole injection layer 111 on the electrode 101, DBT3P-II and molybdenum oxide ( MoO3) were co-evaporated so that the weight ratio (DBT3P-II:MoO3) was 1:0.5 and the thickness was 65 nm.

[0350] Next, as the hole transport layer 112 on the hole injection layer 111, BPAFLP was evaporated to a thickness of 20 nm.

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

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

[0353] Next, on the electron transport layer 118(1), as the electron transport layer 118(2), NBPhen was deposited with a thickness of 20 nm.

[0354] On the electron transport layer 118(2), as the electron injection layer 130, lithium fluoride (LiF) was deposited with a thickness of 1 nm.

[0355] Next, on the electron injection layer 130, as the electrode 102, aluminum (Al) was deposited with a thickness of 20 0 nm.

[0356] Next, it was heat-treated at 80 °C for 1 hour in the air without encapsulation. By the above steps, the comparative light-emitting element 1 was obtained.

[0357] ≪Fabrication of Light-Emitting Element 2≫ The light-emitting element 2 was fabricated with the same method as the comparative light-emitting element 1 shown above, except that the fabrication of the comparative light-emitting element 1 and the formation processes of the electron transport layer 118(2) and the electron injection layer 130 were different. Only the formation processes of the electron transport layer 118(2) and the electron injection layer 130 were different, and the other processes were the same as those of the comparative light-emitting element 1. And it was fabricated in this way.

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

[0359] As the electron injection layer 130 on the electron transport layer 118(2), NBPhn and Ag were co-vapor-deposited at a weight ratio (NBPhn:Ag) of 1:0.38 and a thickness of 10 nm.

[0360] ≪Fabrication of Light-Emitting Element 3 and Light-Emitting Element 4≫ The light-emitting element 3 and the light-emitting element 4 were fabricated with the same method as the light-emitting element 2 shown above, except that only the formation process of the electron injection layer 130 was different. And the other processes were the same as those of the light-emitting element 2.

[0361] <Fabrication of Light-Emitting Element 3> As the electron injection layer 130 on the electron transport layer 118(2) of the light-emitting element 3, Alq3 and Ag were co-vapor-deposited at a weight ratio (Alq3:Ag) of 1:0.48 and a thickness of 10 nm.

[0362] <Fabrication of Light-Emitting Element 4> As the electron injection layer 130 on the electron transport layer 118(2) of the light-emitting element 4, 2mDBTBPDBq-II and Ag were co-vapor-deposited at a weight ratio (2mDBTBPDBq-II:Ag) of 1:0.40 and a thickness of 10 nm.

[0363] <Characteristics of Light-Emitting Element> Next, the element characteristics of the fabricated comparative light-emitting element 1 and light-emitting elements 2 to 4 were measured. For the measurement of luminance and CIE chromaticity, a color luminance meter (Topcon Corporation, BM-5A) was used. For the measurement of the electroluminescence spectrum, a multi-channel spectroscope (Hamamatsu Photonics, PMA- 11) was used.

[0364] The current efficiency-luminance characteristics of the fabricated comparative light-emitting element 1 and light-emitting elements 2 to 4 are shown in Fig. 13. The current density-voltage characteristics are shown in Fig. 14, the power efficiency-luminance characteristics are shown in Fig. 15, and the external quantum efficiency-luminance characteristics are shown in Fig. 16, respectively. The measurement of each light-emitting element was carried out at room temperature (in an atmosphere maintained at 23 °C ). Also, the electric field 2 when a current was passed through each light-emitting element at a current density of 2.5 mA / cm electroluminescence spectrum is shown in Fig. 17. The measurement was carried out at room temperature.

[0365] Also, the element characteristics of the comparative light-emitting element 1 and light-emitting elements 2 to 4 2 near 1000 cd / m are shown in Table 5.

[0366]

Table 5

[0367] As shown in Fig. 16 and Table 5, the comparative light-emitting element 1 and light-emitting elements 2 to 4 all showed high luminous efficiency exceeding an external quantum efficiency of 20%. As shown in Fig. 13 and Fig. 15 , the comparative light-emitting element 1 and light-emitting elements 2 to 4 all showed high efficiency in both current efficiency and power efficiency. In particular, the comparative light-emitting element 1, light-emitting element 2, and light-emitting element 4 showed extremely high efficiency exceeding an external quantum efficiency of 25%. Also, the light-emitting elements 2 and 4, which are one aspect of the present invention, showed high efficiency equivalent to that of the comparative light-emitting element 1 using LiF, a material generally used for the electron injection layer. ​

[0368] Also, as shown in Fig. 14, the comparative light-emitting element 1 and the light-emitting elements 2 to 4 exhibited good current density-voltage characteristics. In particular, the light-emitting element 2 exhibited current density-voltage characteristics equivalent to those of the comparative light-emitting element 1, and it was found that the composite material of NBPhen and Ag has very good electron injection properties.

[0369] Also, as shown in Fig. 17, the peak wavelengths of the electroluminescence spectra of the comparative light-emitting element 1 and the light-emitting elements 2 to 4 were all around 619 nm, and the full width at half maximum was all 58 n m, indicating red light emission. From the obtained electroluminescence spectrum, it was found that the emission was from the guest material Ir(dmdppr-dmp)2(dpm).

[0370] <Reliability Evaluation of Light-Emitting Element> Next, a constant temperature and humidity storage test was conducted on the comparative light-emitting element 1 and the light-emitting elements 2 to 4. Since each light-emitting element was not sealed, the cathode and the EL layer were exposed to the atmosphere of the test environment. Generally, when moisture enters a light-emitting element, dark spots (non-light-emitting regions inside the light-emitting part) and shrinkage (non-light-emitting regions at the ends of the light-emitting part) occur, which have an adverse effect on the reliability of the light-emitting element. Therefore, by conducting a constant temperature and humidity storage test, the reliability of the light-emitting element against moisture can be evaluated.

[0371] The comparative light-emitting element 1 and the light-emitting elements 2 to 4 were each left in a thermostatic chamber maintained at a constant temperature of 65°C and a humidity of 95% for 48 hours, and then the light-emitting state of each light-emitting element was investigated.

[0372] The evaluation of the light-emitting state was performed by estimating the ratio of the light-emitting area before and after the constant temperature and humidity storage test.​​​​​​​​ This was done. Table 6 shows the results.

[0373]

Table 6

[0374] In Table 6, the emission area ratio (%) = the emission area after the thermo-hygrostatic storage test / the emission area before the thermo-hygrostatic test × 100. From Table 6, it was found that the emission area ratios of Light-emitting elements 2 to 4, which are light-emitting elements of one aspect of the present invention, are all larger than those of Comparative Light-emitting element 1 that uses LiF, which is an alkali metal compound, in the electron injection layer. That is, the light-emitting element of one aspect of the present invention was shown to be more moisture-resistant than the light-emitting element that uses a material with a small work function such as an alkali metal in the electron injection layer. This is because a material with a small work function has a high reactivity with water, and moisture enters the inside of the light-emitting element. On the other hand, the light-emitting element of one aspect of the present invention uses a transition metal with poor reactivity with water, so moisture hardly enters the inside of the light-emitting element. Therefore, a light-emitting element with high moisture resistance can be realized. <Absorption spectrum of the composite material of the organic compound and the transition metal>

[0375] <Absorption spectrum of the composite material of the organic compound and the transition metal> Next, the absorption spectra of the thin films of the composite material of the organic compound and Ag used in the electron injection layers of Light-emitting elements 2 to 4 were measured. Additionally, the absorption spectra of the Ag thin film and the organic compound thin film were measured. The results are shown in FIGS. 18 to 20. The thin film of the composite material of the organic compound and Ag was formed by vacuum deposition on a quartz substrate such that the molar ratio (organic compound:Ag) was 1:1 and the thickness was 50 nm. Also, the thin film of the organic compound was formed by vacuum deposition on a quartz substrate such that the thickness was 50 nm. Also, the Ag thin film was formed on the quartz substrate such that the thickness was 50 nm by vacuum deposition. such that the thickness was 50 nm by vacuum deposition. It was formed by vacuum deposition so that the thickness became 2 nm. An Ag thin film with a thickness of 2 nm The amount of substance of Ag contained in is about the same as the amount of substance of Ag contained in a thin film of a composite material of an organic compound and Ag with a thickness of 50 nm. For the measurement of the absorption spectrum, a spectrophotometer (Spectrophotometer U4100 manufactured by Hitachi High-Technologies Corporation) was used.

[0376] From FIGS. 18 to 20, a surface plasmon peak peculiar to a metal thin film was observed at around 450 nm from the Ag thin film. On the other hand, the surface plasmon peak was not observed from the composite material of the organic compound and Ag. Surface plasmons are found on the surface of fine (nanometer scale) metals such as metal thin films and metal nanoparticles. Therefore, in the composite material of the organic compound and Ag, it is suggested that Ag exists not as an aggregate of Ag atoms such as an Ag thin film or Ag nanoparticles, but as Ag atoms and interacts with the organic compound. That is, it can be said that the organic compound and Ag, which is a transition metal, are in a state where the organic compound and the transition metal interact in the mixed film.

[0377] From the above, the light-emitting element which is one aspect of the present invention has excellent electron injection properties, so it is a light-emitting element with a low driving voltage and high luminous efficiency. In addition, since a material with a small work function is not used, it is a light-emitting element with excellent moisture resistance. The configuration shown...

Claims

1. An anode, a cathode, a light-emitting layer between the anode and the cathode, a first layer that forms a SOMO between the light-emitting layer and the cathode, The first layer contains a compound having binding sites arranged in the order of nitrogen, carbon, carbon, and nitrogen, a light-emitting device.

2. An anode, a cathode, a light-emitting layer between the anode and the cathode, a first layer that forms a SOMO between the light-emitting layer and the cathode, The first layer contains a compound having at least one diazine ring or triazine ring, a light-emitting device.

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

4. An anode, a cathode, having a first light-emitting unit and a second light-emitting unit between the anode and the cathode, having a first layer that forms a SOMO between the first light-emitting unit and the second light-emitting unit, The first layer contains a compound having binding sites arranged in the order of nitrogen, carbon, carbon, and nitrogen, a light-emitting device.

5. An anode, a cathode, having a first light-emitting unit and a second light-emitting unit between the anode and the cathode, having a first layer that forms a SOMO between the first light-emitting unit and the second light-emitting unit, The first layer contains a compound having at least one diazine ring or triazine ring, a light-emitting device.

6. In Claim 4 or Claim 5, The host material of the light-emitting layer included in the first light-emitting unit contains a compound having at least one diazine ring or triazine ring, a light-emitting device.

7. In Claim 1 or Claim 4, The compound is a phenanthroline derivative, a light-emitting device.

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