Mixed material for light-emitting device

Abstract

One embodiment of the present invention provides a novel hybrid material for light-emitting devices with improved heat resistance. The hybrid material for light-emitting devices includes a first heteroaromatic compound and a second heteroaromatic compound. The first heteroaromatic compound has a first heteroaromatic ring, which includes a ring having two or more nitrogen atoms and any one of a benzene ring and a pyridine ring, or a ring having a diazine ring or a triazine ring. The second heteroaromatic compound has a second heteroaromatic ring, which includes a ring having two or more nitrogen atoms and any one of a benzene ring and a pyridine ring, or a ring having a diazine ring or a triazine ring. The structures of the first and second heteroaromatic rings are different from each other.

Description

Technical Field

[0001] One embodiment of the present invention relates to a hybrid material for a light-emitting device. Another embodiment of the present invention relates to a light-emitting device, a display module, a lighting module, a display device, a light-emitting device, an electronic device, a lighting equipment, and an electronic device. Note that one embodiment of the present invention is not limited to the above-described technical fields. The technical field of one embodiment of the invention disclosed in this specification relates to an object, method, or manufacturing method. Furthermore, one embodiment of the present invention relates to a process, machine, manufacture, or composition of matter. Therefore, more specifically, examples of the technical field of one embodiment of the present invention disclosed in this specification include semiconductor devices, display devices, light-emitting devices, lighting equipment, memory devices, imaging devices, driving methods for these devices, or manufacturing methods for these devices. Prior Technology

[0002] The practical application of light-emitting devices (organic EL devices) that utilize organic compounds and electroluminescence (EL) is very active. In the basic structure of these devices, an organic compound layer (EL layer) containing luminescent material is sandwiched between a pair of electrodes. By applying a voltage to the device and injecting carriers, luminescence from the luminescent material can be obtained using the recombination energy of these carriers.

[0003] Because this type of light-emitting device is self-emissive, it offers advantages over liquid crystal displays (LCDs) in terms of higher visibility and the elimination of the need for a backlight when used in display pixels. Therefore, this device is suitable for flat panel display components. Furthermore, displays using this device can be manufactured to be thin and lightweight, which is a significant advantage. Moreover, its extremely fast response time is also a key feature.

[0004] Furthermore, because the light-emitting layer of this type of light-emitting device can be continuously formed in two dimensions, surface light emission can be achieved. Since this feature is difficult to obtain using point light sources such as incandescent lamps or LEDs, or line light sources such as fluorescent lamps, it also has high utilization value as a surface light source that can be used for lighting and other applications.

[0005] As mentioned above, displays or lighting devices using light-emitting devices are suitable for a wide variety of electronic devices, and research and development of light-emitting devices with better characteristics are becoming increasingly active.

[0006] Organic compounds used in light-emitting devices have a significant impact on device characteristics. Therefore, it is crucial that the physical properties of the organic compounds used are suitable for the temperature range required by the manufacturing process or application of the light-emitting device, in order to improve the reliability of the device. Consequently, the development of materials that suppress morphological changes caused by heat is becoming increasingly active (Patent Document 1).

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2017-75114 Summary of the Invention

[0008] One objective of one embodiment of the present invention is to provide a novel hybrid material for a light-emitting device. Another objective of another embodiment of the present invention is to provide a novel hybrid material for a light-emitting device with improved heat resistance. Another objective of another embodiment of the present invention is to provide a novel light-emitting device with excellent convenience, practicality, or reliability. Another objective of another embodiment of the present invention is to provide a novel hybrid material for an organic semiconductor device. Another objective of another embodiment of the present invention is to provide a novel hybrid material for an organic semiconductor device with improved heat resistance. Another objective of another embodiment of the present invention is to provide a novel organic semiconductor device with excellent convenience, practicality, or reliability. Another objective of another embodiment of the present invention is to provide a novel light-emitting device with excellent convenience, practicality, or reliability. Another objective of another embodiment of the present invention is to provide a novel electronic device with excellent convenience, practicality, or reliability. Furthermore, another objective of another embodiment of the present invention is to provide a novel lighting device with excellent convenience, practicality, or reliability.

[0009] Furthermore, one objective of another embodiment of the present invention is to provide a novel hybrid material for light-emitting devices that improves heat resistance even during thin-film fabrication. Another objective of another embodiment of the present invention is to provide a light-emitting device with high heat resistance. Another objective of another embodiment of the present invention is to provide a light-emitting device with high heat resistance during the manufacturing process. Another objective of another embodiment of the present invention is to provide a novel hybrid material for organic semiconductor devices that improves heat resistance even during thin-film fabrication. Another objective of another embodiment of the present invention is to provide an organic semiconductor device with high heat resistance. Another objective of another embodiment of the present invention is to provide an organic semiconductor device with high heat resistance during the manufacturing process. Another objective of another embodiment of the present invention is to provide a light-emitting device, organic semiconductor device, light-emitting apparatus, electronic device, display device, and electronic device with low power consumption. Another objective of another embodiment of the present invention is to provide a light-emitting device, light-emitting apparatus, electronic device, display device, and electronic device with low power consumption and high reliability.

[0010] Note that the description of these objectives does not preclude the existence of other objectives. Note that one embodiment of the present invention does not need to achieve all of the above objectives. Note that objectives other than those described above can be derived from the description in the specification, drawings, claims, etc.

[0011] One embodiment of the present invention is a hybrid material for a light-emitting device, the hybrid material comprising a first heteroaromatic compound and a second heteroaromatic compound, the first heteroaromatic compound having a first heteroaromatic ring, the first heteroaromatic ring comprising a ring having two or more nitrogen atoms and any one of a benzene ring and a pyridine ring, or a ring having a diazine ring or a triazine ring, the second heteroaromatic compound having a second heteroaromatic ring, the second heteroaromatic ring comprising a ring having two or more nitrogen atoms and any one of a benzene ring and a pyridine ring, or a ring having a diazine ring or a triazine ring, the structures of the first heteroaromatic ring and the second heteroaromatic ring being different from each other.

[0012] In addition, another embodiment of the present invention is a hybrid material for a light-emitting device, wherein either the first heteroaromatic ring or the second heteroaromatic ring is a fused heteroaromatic ring in the above structure.

[0013] In addition, another embodiment of the present invention is a hybrid material for a light-emitting device, wherein in the above structures, the first heteroaromatic ring and the second heteroaromatic ring are both fused heteroaromatic rings.

[0014] In addition, another embodiment of the present invention is a hybrid material for a light-emitting device, wherein in the above-described structures, at least one of the first heteroaromatic ring and the second heteroaromatic ring is any one of a pyrimidine ring, a pyrazine ring, a pyrazine ring, a triazine ring, a pyridine ring, a pheno-line ring, a quinoline ring, a dibenzoquinoline ring, a quinazoline ring, a benzoquinazoline ring, a dibenzoquinazoline ring, a benzimidazole ring, a benzofuran-pyrimidine ring, and a benzofuran-pyrazine ring.

[0015] In addition, another embodiment of the present invention is a hybrid material for a light-emitting device, wherein in each of the above structures, the glass transition temperature of either the first heteroaromatic compound or the second heteroaromatic compound is 100°C or higher.

[0016] In addition, another embodiment of the present invention is a hybrid material for a light-emitting device, wherein in each of the above structures, the glass transition temperature of either the first heteroaromatic compound or the second heteroaromatic compound is 100°C or more, and the difference between the glass transition temperature of the first heteroaromatic compound and the other is 40°C or more.

[0017] In addition, another embodiment of the present invention is a hybrid material for a light-emitting device, wherein in each of the above structures, the glass transition temperature of the first heteroaromatic compound and the second heteroaromatic compound is 100°C or higher.

[0018] In addition to the light-emitting devices described above, the present invention also includes light-emitting devices comprising a layer that contacts an electrode and contains an organic compound (e.g., a capping layer). Furthermore, light-emitting devices that include not only light-emitting devices but also transistors or substrates are also included within the scope of the invention. Moreover, electronic devices or lighting equipment that include not only the aforementioned light-emitting devices but also any one of a detection unit, an input unit, and a communication unit are also included within the scope of the invention.

[0019] Furthermore, one embodiment of the present invention includes not only a light-emitting device with a light-emitting element, but also a lighting device with a light-emitting element. Therefore, the light-emitting device in this specification refers to an image display device or a light source (including a lighting device). In addition, the light-emitting device also includes modules such as: modules in which connectors such as FPC (Flexible Printed Circuit) or TCP (Tape Carrier Package) are mounted; modules in which a printed circuit board is provided at the TCP end; or modules in which ICs (Integrated Circuits) are directly mounted to the light-emitting device via COG (Chip On Glass) bonding.

[0020] In this specification, the names of the source and drain terminals of a transistor are interchanged according to the transistor's polarity and the potential applied to each terminal. Generally, in an n-channel transistor, the terminal to which a low potential is applied is called the source, and the terminal to which a high potential is applied is called the drain. Similarly, in a p-channel transistor, the terminal to which a low potential is applied is called the drain, and the terminal to which a high potential is applied is called the source. Although for convenience, the source and drain terminals are sometimes assumed to be fixed when describing the transistor's connection relationship, in practice, the names of the source and drain terminals are interchanged according to the aforementioned potential relationships.

[0021] In this specification, the source of a transistor refers to the source region of the semiconductor film used as part of the active layer or the source electrode connected to the semiconductor film. Similarly, the drain of a transistor refers to the drain region of the semiconductor film or the drain electrode connected to the semiconductor film. Furthermore, the gate refers to the gate electrode.

[0022] In this specification, a series connection of transistors refers to, for example, a state where only one of the source and drain terminals of the first transistor is connected to only one of the source and drain terminals of the second transistor. Conversely, a parallel connection of transistors refers to a state where one of the source and drain terminals of the first transistor is connected to one of the source and drain terminals of the second transistor, and the other of the source and drain terminals of the first transistor is connected to the other of the source and drain terminals of the second transistor.

[0023] In this specification, connection refers to electrical connection, which is equivalent to a state capable of supplying or transmitting current, voltage, or potential. Therefore, a connection state does not necessarily refer to a direct connection state, but also includes a state indirectly connected through circuit elements such as wiring, resistors, diodes, and transistors that can supply or transmit current, voltage, or potential.

[0024] Even when independent components are connected to each other in the circuit diagram of this specification, there are actually cases where a single conductive film functions as multiple components, such as when a portion of the wiring is used as an electrode. The scope of connections in this specification includes such cases where a single conductive film functions as multiple components.

[0025] One embodiment of the present invention provides a novel hybrid material for a light-emitting device. Another embodiment provides a novel hybrid material for a light-emitting device with improved heat resistance. Another embodiment provides a novel light-emitting device with excellent convenience, practicality, or reliability. Another embodiment provides a novel hybrid material for an organic semiconductor device. Another embodiment provides a novel hybrid material for an organic semiconductor device with improved heat resistance. Another embodiment provides a novel organic semiconductor device with excellent convenience, practicality, or reliability. Another embodiment provides a novel light-emitting device with excellent convenience, practicality, or reliability. Another embodiment provides a novel electronic device with excellent convenience, practicality, or reliability. Furthermore, another embodiment provides a novel lighting device with excellent convenience, practicality, or reliability.

[0026] Furthermore, another embodiment of the present invention can provide a novel hybrid material for light-emitting devices that improves heat resistance even during thin-film formation. Additionally, another embodiment of the present invention can provide a light-emitting device with high heat resistance. Furthermore, another embodiment of the present invention can provide a light-emitting device with high heat resistance during the manufacturing process. Furthermore, another embodiment of the present invention can provide a novel hybrid material for organic semiconductor devices that improves heat resistance even during thin-film formation. Furthermore, another embodiment of the present invention can provide an organic semiconductor device with high heat resistance. Furthermore, another embodiment of the present invention can provide an organic semiconductor device with high heat resistance during the manufacturing process. Furthermore, another embodiment of the present invention can provide a light-emitting device, organic semiconductor device, light-emitting apparatus, electronic device, display device, and electronic device with low power consumption. Furthermore, another embodiment of the present invention can provide a light-emitting device, light-emitting apparatus, electronic device, display device, and electronic device with low power consumption and high reliability.

[0027] Note that the description of these effects does not preclude the existence of other effects. Note that one embodiment of the present invention does not need to have all the above-described effects. Note that effects other than those described above can be learned and derived from the description in the specification, drawings, claims, etc. Simple Explanation of the Diagram

[0028] Figures 1A to 1E are diagrams illustrating the structure of the light-emitting device according to an embodiment. Figures 2A to 2C are illustrations of the light-emitting device according to an embodiment. Figures 3A to 3C illustrate a method for manufacturing a light-emitting device according to an embodiment. Figures 4A to 4C illustrate a method for manufacturing a light-emitting device according to an embodiment. Figures 5A to 5C illustrate a method for manufacturing a light-emitting device according to an embodiment. Figures 6A to 6C illustrate a method for manufacturing a light-emitting device according to an embodiment. [Figure 7] is a diagram illustrating the light-emitting device according to an embodiment. [Figure 8A] and [Figure 8B] are diagrams illustrating the light-emitting device according to an embodiment. [Figure 9A] and [Figure 9B] are diagrams illustrating the light-emitting device according to an embodiment. [Figure 10A] and [Figure 10B] are diagrams illustrating the light-emitting device according to an embodiment. [Figure 11A] and [Figure 11B] are diagrams illustrating the light-emitting device according to an embodiment. Figures 12A to 12E are illustrations of an electronic device according to an embodiment. Figures 13A to 13E are illustrations of an electronic device according to an embodiment. [Figure 14A] and [Figure 14B] are diagrams illustrating an electronic device according to an embodiment. [Figure 15A] and [Figure 15B] are diagrams illustrating an electronic device according to an embodiment. [Figure 16] is a diagram illustrating an electronic device according to an embodiment. [Figures 17A] to [Figures 17D] are photographs according to an embodiment. [Figures 18A] to [Figures 18C] are photographs according to an embodiment. [Figures 19A] to [Figures 19C] are photographs according to an embodiment. [Figure 20] is a diagram illustrating the structure of the light-emitting device according to an embodiment. [Figure 21] shows the brightness-current density characteristics of light-emitting device 1, comparison light-emitting device 2, and comparison light-emitting device 3. [Figure 22] shows the brightness-voltage characteristics of light-emitting device 1, comparison light-emitting device 2, and comparison light-emitting device 3. [Figure 23] shows the current efficiency-brightness characteristics of light-emitting device 1, comparative light-emitting device 2, and comparative light-emitting device 3. [Figure 24] shows the current-voltage characteristics of light-emitting device 1, comparison light-emitting device 2, and comparison light-emitting device 3. [Figure 25] shows the external quantum efficiency-brightness characteristics of light-emitting device 1, comparative light-emitting device 2, and comparative light-emitting device 3. [Figure 26] shows the emission spectra of light-emitting device 1, comparative light-emitting device 2, and comparative light-emitting device 3. [Figure 27] is a diagram showing the reliability of light-emitting device 1, comparative light-emitting device 2, and comparative light-emitting device 3. Figures 28A to 28C are illustrations of a display device according to an embodiment. Implementation

[0029] The embodiments of the present invention are described in detail below using drawings. However, the present invention is not limited to the following description, and those skilled in the art will readily understand that the methods and details of the present invention can be transformed into various forms without departing from its spirit and scope. Therefore, the present invention should not be construed as being limited only to the contents described in the embodiments shown below.

[0030] Implementation Method 1 In this embodiment, a hybrid material for a light-emitting device according to one embodiment of the present invention will be described. By using this hybrid material for a light-emitting device, the heat resistance of the thin film can be improved. In other words, the hybrid material for a light-emitting device according to one embodiment of the present invention can effectively suppress morphological changes caused by thin film formation. Note that the hybrid material for a light-emitting device shown in this embodiment can also be applied to organic semiconductor devices, and can be referred to as a hybrid material for organic semiconductor devices.

[0031] One embodiment of the present invention provides a hybrid material for a light-emitting device comprising a first heteroaromatic compound and a second heteroaromatic compound. The first heteroaromatic compound has a first heteroaromatic ring, which includes a ring having two or more nitrogen atoms and either a benzene ring or a pyridine ring, or a ring having a diazine ring or a triazine ring. The second heteroaromatic compound has a second heteroaromatic ring, which includes a ring having two or more nitrogen atoms and either a benzene ring or a pyridine ring, or a ring having a diazine ring or a triazine ring. The structures of the first and second heteroaromatic rings are different from each other. Note that the aforementioned diazine ring includes pyrimidine rings, pyrazine rings, and triazine rings.

[0032] Furthermore, the aforementioned heteroaromatic rings include fused heteroaromatic rings with fused ring structures. Examples of fused heteroaromatic rings include quinoline rings, benzo[a]quinoline rings, quinoline rings, dibenzo[a]quinoline rings, quinazoline rings, benzo[a]quinoline rings, dibenzo[a]quinoline rings, phenoline rings, benzofuran diazine rings (e.g., benzofuran-pyrimidine rings or benzofuran-pyrazine rings), and benzimidazole rings. Note that, for example, quinoline rings, benzo[a]quinoline rings, and phenoline rings include pyridine ring structures. Quinoline rings, dibenzo[a]quinoline rings, and benzofuran-pyrazine rings include pyrazine ring structures. Furthermore, quinoline rings, benzo[a]quinoline rings, dibenzo[a]quinoline rings, and benzofuran-pyrimidine rings include pyrimidine ring structures.

[0033] In addition, as another embodiment of the present invention, in the above structure of the hybrid material for light-emitting devices, either the first heteroaromatic ring or the second heteroaromatic ring is a fused heteroaromatic ring.

[0034] In addition, as another embodiment of the present invention, in the above structure of the hybrid material for light-emitting devices, both the first heteroaromatic ring and the second heteroaromatic ring are fused heteroaromatic rings.

[0035] Note that when the heteroaromatic compounds in the above-mentioned light-emitting device composite material have fused heteroaromatic rings as heteroaromatic rings, the thermal properties of the light-emitting device composite material are improved compared with those containing a large number of heteroaromatic compounds that do not have fused heteroaromatic rings, such as the glass transition temperature (Tg) and crystallization temperature (Tc).

[0036] As described above, the thermal properties are improved by having fused heteroaromatic rings. However, when a thin film (monofilm) is formed from only one heteroaromatic compound having fused heteroaromatic rings, even if a stable glassy state is obtained, it is sometimes difficult to maintain this state due to strong intermolecular interactions. That is, in a thin film (monofilm) formed from only one heteroaromatic compound, the glassy state should be maintained at a temperature below Tg, but crystallization that would not normally occur may be observed when exposed to the atmosphere or stimulated at low temperatures below Tg. Thus, if the glassy state of the thin film (monofilm) cannot be maintained at a temperature below Tg, and processing of the organic EL layer in the light-emitting device process requires atmospheric processing, the organic EL layer may crystallize during processing, affecting the characteristics of the light-emitting device. However, the hybrid material for light-emitting devices according to one embodiment of the present invention can suppress film crystallization. As described above, the hybrid material for light-emitting devices according to one embodiment of the present invention can prevent film crystallization below Tg while increasing Tg. The results shown in Examples 1 to 3 also demonstrate this.

[0037] Note that at least one of the heteroaromatic compounds contained in the above-mentioned light-emitting device mixed material has any one of the following heteroaromatic rings: pyrimidine ring, pyrazine ring, thiazoline ring, triazine ring, pyridine ring, pheno-line ring, quinoline ring, dibenzoquinoline ring, quinazoline ring, benzoquinazoline ring, dibenzoquinazoline ring, benzimidazole ring, benzofuran-pyrimidine ring, and benzofuran-pyrazine ring.

[0038] Furthermore, the glass transition temperature (Tg) of at least one of the heteroaromatic compounds included in the aforementioned light-emitting device composite material is preferably 100°C or higher, or when the light-emitting device composite material includes two heteroaromatic compounds, the glass transition temperature (Tg) of one of the heteroaromatic compounds is preferably 100°C or higher. By employing this structure, the crystallization that occurs below Tg will not occur below 100°C. Therefore, in the process of manufacturing light-emitting devices where processing of the organic EL layer needs to be carried out in the atmosphere, heating up to 100°C can be performed in this process, thereby improving the flexibility of the process.

[0039] Furthermore, when the hybrid material for the light-emitting device contains two heteroaromatic compounds, it is preferable that the glass transition temperature of one heteroaromatic compound is 100°C or higher and the difference between the glass transition temperature of one heteroaromatic compound and that of the other heteroaromatic compound is 40°C or higher.

[0040] In addition, the glass transition temperature of all heteroaromatic compounds contained in the hybrid material for light-emitting devices is preferably above 100°C.

[0041] Furthermore, the hybrid material used in the aforementioned light-emitting device preferably does not contain metal complexes. Examples of such metal complexes include alkali metal complexes and alkaline earth metal complexes, particularly alkali metal hydroxyquinoline complexes or alkaline earth metal hydroxyquinoline complexes. These metal complexes may react with water in the atmosphere, and therefore are not suitable for manufacturing methods of organic EL devices that include a process in which the organic EL layer of the light-emitting device needs to be processed in the atmosphere. On the other hand, even if a process in which the organic EL layer of the light-emitting device needs to be processed in the atmosphere is included, metal complexes can be appropriately used if the organic EL layer is formed only by an inert gas process or a process under reduced pressure after the atmospheric process.

[0042] Furthermore, one or more combinations of heteroaromatic compounds represented by structural formulas (101) to (118) can be used in a hybrid material for a light-emitting device according to one embodiment of the present invention.

[0043] [Chemical Formula 1]

[0044] [Chemical Formula 2]

[0045] When the mixed material for the aforementioned light-emitting device includes two heteroaromatic compounds, it is preferable to mix them in a manner where one heteroaromatic compound with higher electron transport properties is mixed at a ratio of 10% wt or more, preferably 20% wt or more, and more preferably 30% wt or more of the other heteroaromatic compound, which can improve heat resistance.

[0046] Note that when the heteroaromatic compound specifically shown as the electron transport material in Embodiment 2 is equivalent to the specific heteroaromatic compound shown in this embodiment that can be used in the mixed material for light-emitting devices, refer to that compound; its description is omitted in this embodiment.

[0047] The structure shown in this embodiment can be implemented by appropriately combining it with the structures shown in other embodiments.

[0048] Implementation Method 2 In this embodiment, a hybrid material for a light-emitting device using the hybrid material shown in Embodiment 1 will be described with reference to FIGS. 1A to 1E.

[0049] <<Basic Structure of Light-Emitting Devices>> The basic structure of the light-emitting device is described below. Figure 1A shows a light-emitting device with an EL layer having a light-emitting layer between a pair of electrodes. Specifically, an EL layer 103 is included between the first electrode 101 and the second electrode 102.

[0050] Figure 1B illustrates a light-emitting device with a stacked structure (series structure) comprising multiple (two layers in Figure 1B) EL layers (103a, 103b) between a pair of electrodes and a charge generation layer 106 between the EL layers. Light-emitting devices with a series structure can realize light-emitting devices capable of low-voltage driving and low power consumption.

[0051] The charge generation layer 106 functions to inject electrons into one EL layer (103a or 103b) and holes into the other EL layer (103b or 103a) when a potential difference is generated between the first electrode 101 and the second electrode 102. Thus, in FIG1B, when a voltage is applied such that the potential of the first electrode 101 is higher than that of the second electrode 102, the charge generation layer 106 injects electrons into the EL layer 103a and holes into the EL layer 103b.

[0052] Furthermore, from the viewpoint of light extraction efficiency, the charge generation layer 106 is preferably transparent to visible light (specifically, the visible light transmittance of the charge generation layer 106 is 40% or more). Additionally, it can function even if the conductivity of the charge generation layer 106 is lower than that of the first electrode 101 or the second electrode 102.

[0053] Figure 1C shows the stacked structure of the EL layer 103 of a light-emitting device according to one embodiment of the present invention. Note that in this case, the first electrode 101 is used as the anode and the second electrode 102 is used as the cathode. The EL layer 103 has a structure in which a hole injection layer 111, a hole transport layer 112, a light-emitting layer 113, an electron transport layer 114, and an electron injection layer 115 are sequentially stacked on the first electrode 101. Note that the light-emitting layer 113 may also be stacked with multiple light-emitting layers of different emitting colors. For example, a light-emitting layer containing a light-emitting material emitting red light, a light-emitting layer containing a light-emitting material emitting green light, and a light-emitting layer containing a light-emitting material emitting blue light may be stacked with or without separation from layers containing carrier transport materials. Alternatively, a light-emitting layer containing a light-emitting material emitting yellow light and a light-emitting layer containing a light-emitting material emitting blue light may be combined. Note that the stacked structure of the light-emitting layer 113 is not limited to the above structures. For example, the light-emitting layer 113 may also be stacked with multiple light-emitting layers of the same emitting color. For example, a first luminescent layer containing a blue light-emitting material and a second luminescent layer containing a blue light-emitting material can be stacked with or without separation between layers containing carrier transport materials. When multiple luminescent layers of the same color are stacked, reliability can sometimes be improved compared to a single layer. Furthermore, in the series structure shown in FIG1B, which includes multiple EL layers, each EL layer is stacked sequentially from the anode side as described above. Additionally, when the first electrode 101 is the cathode and the second electrode 102 is the anode, the stacking order of the EL layers 103 is reversed. Specifically, on the first electrode 101 of the cathode, 111 is the electron injection layer, 112 is the electron transport layer, 113 is the luminescent layer, 114 is the hole transport layer, and 115 is the hole injection layer.

[0054] By appropriately combining luminescent materials and multiple substances, the luminescent layer 113 in the EL layers (103, 103a, and 103b) can achieve fluorescence, phosphorescence, or both, emitting a desired color. Alternatively, the luminescent layer 113 can also have a stacked structure with different luminescent colors. In this case, different materials can be used as the luminescent materials and other substances for each luminescent layer. Furthermore, a structure can be adopted where multiple EL layers (103a and 103b) as shown in FIG. 1B produce different luminescent colors from each other. In this case, different materials can be used as the luminescent materials and other substances for each luminescent layer.

[0055] In addition, in a light-emitting device according to one embodiment of the present invention, for example, by making the first electrode 101 shown in FIG1C a reflective electrode, making the second electrode 102 a semi-transmissive-semi-reflective electrode and adopting an optical microcavity resonator (microcavity) structure, the light obtained from the light-emitting layer 113 in the EL layer 103 can resonate between the electrodes, thereby enhancing the light obtained through the second electrode 102.

[0056] When the first electrode 101 of the light-emitting device is a reflective electrode composed of a stacked structure of a reflective conductive material and a light-transmitting conductive material (transparent conductive film), optical adjustment can be performed by controlling the thickness of the transparent conductive film. Specifically, it is preferable to adjust it in such a way that when the wavelength of the light obtained from the light-emitting layer 113 is λ, the optical distance (product of thickness and refractive index) between the first electrode 101 and the second electrode 102 is mλ / 2 (note that m is a natural number) or a value close to it.

[0057] Furthermore, in order to amplify the desired light (wavelength: λ) obtained from the light-emitting layer 113, it is preferable to adjust the optical distances as follows: the optical distances from the first electrode 101 to the region in the light-emitting layer 113 where the desired light can be obtained (the light-emitting region) and the optical distances from the second electrode 102 to the region in the light-emitting layer 113 where the desired light can be obtained (the light-emitting region) are both (2m'+1)λ / 4 (note that m' is a natural number) or a value close to that. Note that the "light-emitting region" explained here refers to the recombination region of holes and electrons in the light-emitting layer 113.

[0058] By making the above optical adjustments, the spectrum of specific monochromatic light that can be obtained from the light-emitting layer 113 can be narrowed, thereby obtaining light emission with good color purity.

[0059] Furthermore, in the above-described case, strictly speaking, the optical distance between the first electrode 101 and the second electrode 102 can be considered as the total thickness from the reflective region in the first electrode 101 to the reflective region in the second electrode 102. However, since it is difficult to accurately determine the positions of the reflective regions in the first electrode 101 and the second electrode 102, the aforementioned effect can be sufficiently obtained by assuming any position in the first electrode 101 and the second electrode 102 as a reflective region. Furthermore, strictly speaking, the optical distance between the first electrode 101 and the light-emitting layer from which the desired light is obtained can be considered as the optical distance between the reflective region in the first electrode 101 and the light-emitting region in the light-emitting layer from which the desired light is obtained. However, since it is difficult to accurately determine the positions of the reflective region in the first electrode 101 and the light-emitting region in the light-emitting layer from which the desired light is obtained, the aforementioned effect can be sufficiently obtained by assuming any position in the first electrode 101 as a reflective region and any position in the light-emitting layer from which the desired light is obtained as a light-emitting region.

[0060] The light-emitting device shown in Figure 1D is a tandem light-emitting device with a microcavity structure, allowing the extraction of light (monochromatic light) of different wavelengths from each EL layer (103a, 103b). Therefore, separate coatings (e.g., R, G, B) are not required to obtain different emission colors. This facilitates the achievement of high resolution. Furthermore, it can be combined with color layers (color filters). Moreover, the emission intensity in the front direction with a specific wavelength can be enhanced, thereby achieving low power consumption.

[0061] The light-emitting device shown in Figure 1E is an example of the series-connected structure shown in Figure 1B. As illustrated, it has a stacked structure with three EL layers (103a, 103b, 103c) sandwiching charge-generating layers (106a, 106b). Each of the three EL layers (103a, 103b, 103c) includes a light-emitting layer (113a, 113b, 113c), and the emission colors of each light-emitting layer can be freely combined. For example, light-emitting layers 113a and 113c can be blue, and light-emitting layer 113b can be red, green, or yellow. Alternatively, for example, light-emitting layers 113a and 113c can be red, and light-emitting layer 113b can be blue, green, or yellow.

[0062] Furthermore, in the light-emitting device according to one embodiment of the present invention described above, at least one of the first electrode 101 and the second electrode 102 is a light-transmitting electrode (transparent electrode, semi-transmissive-semi-reflective electrode, etc.). When the light-transmitting electrode is a transparent electrode, the visible light transmittance of the transparent electrode is 40% or more. Furthermore, when the electrode is a semi-transmissive-semi-reflective electrode, the visible light reflectance of the semi-transmissive-semi-reflective electrode is 20% or more and 80% or less, preferably 40% or more and 70% or less. Additionally, the resistivity of these electrodes is preferably 1 × 10⁻² Ωcm or less.

[0063] Furthermore, in the light-emitting device according to one embodiment of the present invention described above, when one of the first electrode 101 and the second electrode 102 is a reflective electrode (reflective electrode), the visible light reflectance of the reflective electrode is 40% or more and 100% or less, preferably 70% or more and 100% or less. Additionally, the resistivity of this electrode is preferably 1 × 10⁻² Ωcm or less.

[0064] <<Specific Structure of Light-Emitting Devices>> Next, the specific structure of a light-emitting device according to one embodiment of the present invention will be described. Again, the description will refer to FIG. 1D, which has a series structure. Note that the light-emitting devices with a single structure shown in FIGS. 1A and 1C also have the same EL layer structure. Furthermore, in the case where the light-emitting device shown in FIG. 1D has a microcavity structure, a reflective electrode is formed as the first electrode 101, and a semi-transmissive-semi-reflective electrode is formed as the second electrode 102. Thus, the electrodes can be formed in a single layer or in a stack using a desired electrode material alone or using multiple electrode materials. Additionally, the second electrode 102 is formed using the same material as described above after the formation of the EL layer 103b.

[0065] <First Electrode and Second Electrode> As materials for forming the first electrode 101 and the second electrode 102, the following materials can be appropriately combined if they can satisfy the functions of the two electrodes. For example, metals, alloys, conductive compounds, and mixtures thereof can be appropriately used. Specifically, examples include In-Sn oxide (also known as ITO), In-Si-Sn oxide (also known as ITSO), In-Zn oxide, and In-W-Zn oxide. In addition to the above, metals such as aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), and neodymium (Nd), as well as alloys appropriately combined therein, can also be used. In addition to the above, elements belonging to Group 1 or Group 2 of the periodic table (e.g., rare earth metals such as lithium (Li), cesium (Cs), calcium (Ca), strontium (Sr)), europium (Eu), ytterbium (Yb), alloys of them appropriately combined, and graphene, etc., can be used.

[0066] In the light-emitting device shown in FIG1D, where the first electrode 101 is the anode, the hole injection layer 111a and the hole transport layer 112a of the EL layer 103a are sequentially deposited on the first electrode 101 by vacuum evaporation. After the EL layer 103a and the charge generation layer 106 are formed, the hole injection layer 111b and the hole transport layer 112b of the EL layer 103b are sequentially deposited on the charge generation layer 106 in the same manner as described above.

[0067] <Electric Hole Injection Layer> The hole injection layer (111, 111a, 111b) is a layer in which holes are injected from the first electrode 101 of the anode and the charge generation layer (106, 106a, 106b) into the EL layer (103, 103a, 103b), and contains organic acceptor material or material with high hole injection capability.

[0068] Organic acceptor materials can generate holes in organic compounds by charge separation between them and other organic compounds whose HOMO energy level is close to the LUMO energy level. Therefore, compounds with electron-withdrawing groups (halogen or cyano groups) such as quinone dimethane derivatives, tetrachlorobenzoquinone derivatives, and hexaazatribenzene derivatives can be used as organic acceptor materials. For example, 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinone dimethyl ether (abbreviated as F4-TCNQ), 3,6-difluoro-2,5,7,7,8,8-hexacyano-p-quinone dimethyl ether, chloroquinone, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatribenzene (abbreviated as HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinone dimethyl ether (abbreviated as F6-TCNNQ), and 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyrene-2-yl)malononitrile, etc., can be used. In organic acceptor materials, compounds such as HAT-CN with electron-withdrawing groups bonded to fused aromatic rings with multiple heteroatoms have high acceptor properties and thermal stability, making them particularly superior. In addition, [3] axylene derivatives including electron-withdrawing groups (especially halogen groups such as fluorine groups or cyano groups) have very high electron acceptor properties and are therefore superior. Specifically, the following can be used: α,α',α”-1,2,3-cycloalkyltrimethylenetri[4-cyano-2,3,5,6-tetrafluorophenylacetonitrile], α,α',α”-1,2,3-cyclopropyltrimethylenetri[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)phenylacetonitrile], α,α',α”-1,2,3-cycloalkyltrimethylenetri[2,3,4,5,6-pentafluorophenylacetonitrile], etc.

[0069] As materials with high hole injection properties, oxides of metals belonging to Groups 4 to 8 of the periodic table (such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, manganese oxide, and other transition metal oxides) can be used. Specifically, examples include molybdenum oxide, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, tungsten oxide, manganese oxide, and rhenium oxide. Among these, molybdenum oxide is particularly preferred due to its atmospheric stability, low hygroscopicity, and ease of handling. In addition to the above, phthalocyanine compounds such as phthalocyanine (H₂Pc) and copper phthalocyanine (CuPc) can be used.

[0070] In addition to the materials mentioned above, aromatic amine compounds of low molecular weight compounds such as 4,4',4”-tris(N,N-diphenylamino)triphenylamine (abbreviated as TDATA), 4,4',4”-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviated as MTDATA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB), and N-N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4 4'-Diamine (abbreviated as DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviated as DPA3B), 3-[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviated as PCzPCA1), 3,6-bis[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviated as PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazole-3-yl)amino]-9-phenylcarbazole (abbreviated as PCzPCN1), etc.

[0071] Alternatively, polymeric compounds (oligomers, dendritic polymers, or polymers, etc.) can be used, such as poly(N-vinylcarbazole) (PVK), poly(4-vinyltriphenylamine) (PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (PTPDMA), and poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (Poly-TPD). Alternatively, polymeric compounds containing acids can be used, such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (PEDOT / PSS) and polyaniline / poly(styrenesulfonic acid) (PAni / PSS).

[0072] As a material with high hole injection capability, a hybrid material comprising a hole transport material and the aforementioned organic acceptor material (electron acceptor material) can also be used. In this case, electrons are extracted from the hole transport material by the organic acceptor material to generate a hole in the hole injection layer 111, and the hole is injected into the light-emitting layer 113 via the hole transport layer 112. Alternatively, the hole injection layer 111 can be a single layer composed of a hybrid material comprising a hole transport material and an organic acceptor material (electron acceptor material), or it can be a stack of layers formed using hole transport materials and organic acceptor materials (electron acceptor materials) respectively.

[0073] As a hole transport material, it is preferable to use a material with a hole mobility of 1×10⁻⁶ cm² / Vs or higher when the square root of the electric field strength [V / cm] is 600. Alternatively, any material other than the one mentioned above may be used as long as its hole transport capability is higher than its electron transport capability.

[0074] As a hole-transporting material, it is preferable to use compounds with π-electron-rich heteroaromatic rings (e.g., carbazole derivatives, furan derivatives and thiophene derivatives) or aromatic amines (organic compounds containing aromatic amine skeletons) and other materials with high hole transport properties.

[0075] Examples of the aforementioned carbazole derivatives (organic compounds having a carbazole skeleton) include bicarbazole derivatives (e.g., 3,3'-bicarbazole derivatives) and aromatic amines having a carbazole group.

[0076] As examples of the aforementioned bicarbazole derivatives (e.g., 3,3'-bicarbazole derivatives), specifically, 3,3'-bis(9-phenyl-9H-carbazole) (abbreviated as PCCP), 9,9'-bis(biphenyl-4-yl)-3,3'-bi-9H-carbazole (abbreviated as BisBPCz), 9,9'-bis(1,1'-biphenyl-3-yl)-3,3'-bi-9H-carbazole (abbreviated as BisBPCz), 9-(1,1'-biphenyl-3-yl)-9'-(1,1'-biphenyl-4-yl)-9H,9'H-3,3'-bicarbazole (abbreviated as mBPCCBP), 9-(2-naphthyl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviated as βNCCP), etc.

[0077] Furthermore, as aromatic amines containing a carbazole group, examples specifically include 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as: PCBA1BP), N-(4-biphenyl)-N-(9,9-dimethyl-9H-furo-2-yl)-9-phenyl-9H-carbazole-3-amine (abbreviated as: PCBiF), N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-furo-2-amine (abbreviated as: PCBBiF), 4,4'-diphenyl-4”-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as: PCBBi1BP), and 4-(1-naphthyl)-4'-(9- Phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4”-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCCNBB), 4-phenyldiphenyl-(9-phenyl-9H-carbazole-3-yl)amine (abbreviation: PCA1BP), N,N'-bis(9-phenylcarbazole-3-yl)-N,N'-diphenylphenyl-1,3-diamine (abbreviation: PCA2B), N,N',N”-triphenyl-N,N',N”-tris(9-phenylcarbazole-3-yl)phenyl-1,3,5-triamine (abbreviation: PCA3B), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]fuco -2-amine (abbreviated as: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]spiro-9,9'-diphenyl-2-amine (abbreviated as: PCBASF), 3-[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviated as: PCzPCA1), 3,6-bis[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviated as: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazole-3-yl)amino]-9-phenylcarbazole (abbreviated as: PCzPCN1), 3-[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviated as: PCzD) PA1), 3,6-bis[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA2), 3,6-bis[N-(4-diphenylaminophenyl)-N-(1-naphthyl)amino]-9-phenylcarbazole (abbreviation: PCzTPN2), 2-[N-(9-phenylcarbazole-3-yl)-N-phenylamino]spiro-9,9'-dienyl (abbreviation: PCASF), N-[4-(9H-carbazole-9-yl)phenyl]-N-(4-phenyl)phenylaniline (abbreviation: YGA1BP), N,N'-bis[4-(carbazole-9-yl)phenyl]-N,N'-diphenyl-9,9-dimethylenyl-2,7-diamine (abbreviation: YGA2F), 4,4',4”-Tris(carbazole-9-yl)triphenylamine (TCTA), etc.

[0078] Note that, in addition to the above, other examples of carbazole derivatives include 3-[4-(9-phenanthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviated as PCPPn), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviated as PCPN), 1,3-bis(N-carbazolyl)benzene (abbreviated as mCP), 4,4'-bis(N-carbazolyl)biphenyl (abbreviated as CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviated as CzTP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviated as TCPB), and 9-[4-(10-phenyl-9-anthrayl)phenyl]-9H-carbazole (abbreviated as CzPA), etc.

[0079] As examples of the aforementioned furan derivatives (organic compounds having a furan ring), specific examples include 4,4',4”-(benzyl-1,3,5-triyl)tris(dibenzofuran) (abbreviated as: DBF3P-II) and 4-{3-[3-(9-phenyl-9H-furan-9-yl)phenyl]phenyl}dibenzofuran (abbreviated as: mmDBFFLBi-II), etc.

[0080] As examples of the aforementioned thiophene derivatives (organic compounds having a thiophene ring), specific examples include 4,4',4”-(benzyl-1,3,5-triyl)tris(dibenzothiophene) (abbreviated as: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-en-9-yl)phenyl]dibenzothiophene (abbreviated as: DBTFLP-III), and 4-[4-(9-phenyl-9H-en-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviated as: DBTFLP-IV), etc.

[0081] Specifically, examples of the aforementioned aromatic amines include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as NPB or α-NPD), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviated as TPD), 4,4'-bis[N-(spiro-9,9'-dien-2-yl)-N-phenylamino]biphenyl (abbreviated as BSPB), 4-phenyl-4'-(9-phenylenen-9-yl)triphenylamine (abbreviated as BPAFLP), 4-phenyl-3'-(9-phenylenen-9-yl)triphenylamine (abbreviated as mBPAFLP), and N-(9,9-dimethyl-9H-enen-2-yl)-N-{9, 9-Dimethyl-2-[N'-phenyl-N'-(9,9-dimethyl-9H-furo-2-yl)amino]-9H-furo-7-yl}phenylamine (abbreviation: DFLADFL), N-(9,9-dimethyl-2-diphenylamino-9H-furo-7-yl)diphenylamine (abbreviation: DPNF), 2-[N-(4-diphenylaminophenyl)-N-phenylamino]spiro-9,9'-difuro (abbreviation: DPASF), 2,7-bis[N-(4-diphenylaminophenyl)-N-phenylamino]spiro-9,9'-difuro (abbreviation: DPA2SF), 4,4',4”-tris[N-(1-naphthyl)-N-phenylamino]triphenylamine (abbreviation: 1'-TNATA), 4,4',4” -Tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4',4”-Tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: m-MTDATA), N,N'-Di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4'-Bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), DNTPD, 1,3,5-Tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BnfABP), N, N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf), 4,4'-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl)-4”-phenyltriphenylamine (abbreviation: BnfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-6-amine (abbreviation: BBABnf(6)), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-4-amine (abbreviation: BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzothiophen-4-yl)phenyl]-N-phenyl-4-benzidine (abbreviation: ThBA1BP), 4-(2-naphthyl)-4',4”-diphenyltriphenylamine (abbreviation: BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4”-diphenyltriphenylamine (abbreviation: BBAβNBi), 4,4'-diphenyl-4”-(6;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB), 4,4'-diphenyl-4”-(7;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβN) B-03), 4,4'-diphenyl-4”-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4,4'-diphenyl-4”-(6;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B), 4,4'-diphenyl-4”-(7;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-diphenyl-4”-(4;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB), 4,4'-diphenyl-4”-(5;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenyl)-4'-( 2-Naphthyl)-4”-phenyltriphenylamine (abbreviation: TPBiAβNB), 4-(3-biphenyl)-4'-[4-(2-naphthyl)phenyl]-4”-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4-biphenyl)-4'-[4-(2-naphthyl)phenyl]-4”-phenyltriphenylamine (abbreviation: TPBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine (abbreviation: αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviation: αNBB1BP), 4,4'-diphenyl-4”-[4'-(carbazol-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3- [Phenyl-9H-carbazole-9-yl)phenyl]tri(1,1'-biphenyl-4-yl)amine (abbreviation: YGTBi1BP-02), 4-[4'-(carbazole-9-yl)biphenyl-4-yl]-4'-(2-naphthyl)-4”-phenyltriphenylamine (abbreviation: YGTBiβNB), N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirobis[9H-furan]-2-amine (abbreviation: PCBNBSF), N,N-bis([1,1'-biphenyl]-4-yl)-9,9'-spirobis[9H-furan]-2-amine (abbreviation: BBASF), N,N-bis([1,1'-biphenyl]-4-yl)-9,9'-spirobis[9H-furan]-4-amine (abbreviation: BBASF(4)), N-(1,1'-biphenyl-2-yl)-N-(9,9-dimethyl-9H-furan-2-yl)-9,9'-spirobis[9H-furan]-4-amine (abbreviation: oFBiSF), N-(4-biphenyl)-N-(9,9-dimethyl-9H-furan-2-yl)dibenzofuran-4-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4 4'-[4-(9-phenylenzo-9-yl)phenyl]triphenylamine (abbreviated as BPAFLBi), N,N-bis(9,9-dimethyl-9H-enzo-2-yl)-9,9'-spirobis-9H-enzo-4-amine, N,N-bis(9,9-dimethyl-9H-enzo-2-yl)-9,9'-spirobis-9H-enzo-3-amine, N,N-bis(9,9-dimethyl-9H-enzo-2-yl)-9,9'-spirobis-9H-enzo-2-amine, N,N-bis(9,9-dimethyl-9H-enzo-2-yl)-9,9'-spirobis-9H-enzo-1-amine, etc.

[0082] In addition, as hole-transporting materials, polymeric compounds (oligomers, dendritic polymers, polymers, etc.) can be used, such as poly(N-vinylcarbazole) (PVK), poly(4-vinyltriphenylamine) (PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (PTPDMA), and poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (Poly-TPD). Alternatively, polymeric compounds containing acids can be used, such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (PEDOT / PSS) or polyaniline / poly(styrenesulfonic acid) (PAni / PSS).

[0083] Note that hole-transporting materials are not limited to the materials mentioned above; one or more combinations of known materials can be used as hole-transporting materials.

[0084] Note that the hole-injected layers (111, 111a, 111b) can be formed using various known film-forming methods, such as vacuum evaporation.

[0085] <Hole Transport Layer> The hole transport layers (112, 112a, 112b) are layers that transport holes injected from the first electrode 101 through the hole injection layers (111, 111a, 111b) to the light-emitting layers (113, 113a, 113b). Furthermore, the hole transport layers (112, 112a, 112b) are layers containing a hole-transporting material. Therefore, as the hole transport layers (112, 112a, 112b), a hole-transporting material suitable for use in the hole injection layers (111, 111a, 111b) can be used.

[0086] Note that in one embodiment of the light-emitting device of the present invention, the same organic compound as that used in the hole transport layers (112, 112a, 112b) can be used in the light-emitting layers (113, 113a, 113b). Using the same organic compound in both the hole transport layers (112, 112a, 112b) and the light-emitting layers (113, 113a, 113b) is preferable because it allows for efficient hole transport from the hole transport layers (112, 112a, 112b) to the light-emitting layers (113, 113a, 113b).

[0087] <Emitting Layer> The luminescent layers (113, 113a, 113b) are layers containing luminescent materials. For the luminescent materials used in the luminescent layers (113, 113a, 113b), materials exhibiting luminescent colors such as blue, purple, blue-violet, green, yellow-green, yellow, orange, and red can be appropriately used. Furthermore, when multiple luminescent layers are included, by using different luminescent materials in each layer, structures exhibiting different luminescent colors can be created (for example, white light can be obtained by combining luminescent colors that are complementary colors). Moreover, a stacked structure in which a single luminescent layer contains different luminescent materials can also be employed.

[0088] In addition, the luminescent layers (113, 113a, 113b) may contain one or more organic compounds (host materials, etc.) besides the luminescent material (guest material).

[0089] Note that when multiple host materials are used in the emitting layers (113, 113a, 113b), the newly added second host material is preferably a material with a band gap larger than that of the conventional guest material and the first host material. Furthermore, it is preferable that the lowest singlet excitation energy level (S1 level) of the second host material is higher than the S1 level of the first host material, and that the lowest singlet excitation energy level (T1 level) of the second host material is higher than the T1 level of the guest material. Furthermore, it is preferable that the lowest triplet excitation energy level (T1 level) of the second host material is higher than the T1 level of the first host material. By employing the above structure, an excited-state complex can be formed from the two host materials. Note that for efficient formation of the excited-state complex, it is particularly preferable to combine a compound that readily accepts holes (a hole-transporting material) and a compound that readily accepts electrons (an electron-transporting material). Furthermore, by employing the above structure, high efficiency, low voltage, and long lifetime can be achieved simultaneously.

[0090] Note that, as organic compounds used as the host materials (including the first and second host materials), as long as they meet the conditions for host materials used in the luminescent layer, organic compounds such as hole-transporting materials suitable for the hole transport layers (112, 112a, 112b) and electron transporting materials suitable for the electron transport layers (114, 114a, 114b) can be used. Exciplexes formed from multiple organic compounds (the first and second host materials) can also be used. Furthermore, exciplexes formed from multiple organic compounds in the excited state have the function of converting triple excitation energy into single excitation energy due to the extremely small difference between the S1 and T1 energy levels. As a combination of multiple organic compounds forming the exciplex, it is preferable, for example, that one has a π-electron-deficient heteroaryl ring and the other has a π-electron-rich heteroaryl ring. Furthermore, phosphorescent materials such as iridium, rhodium, platinum-based organometallic complexes or metal complexes can also be used as one of the combinations forming the exciplex.

[0091] There are no particular restrictions on the luminescent materials that can be used in the luminescent layers (113, 113a, 113b). Luminescent materials that convert single excitation energy into light in the visible region or luminescent materials that convert triple excitation energy into light in the visible region can be used.

[0092] <<Converting singlet excitation energy into luminescent material>> As luminescent materials that can be used in luminescent layers (113, 113a, 113b) to convert singlet excitation energy into luminescence, examples include fluorescent materials (fluorescent materials), such as pyrene derivatives, anthracene derivatives, triphenylene derivatives, fenestration derivatives, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, dibenzoquinoline derivatives, quinoline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, and naphthalene derivatives. Pyrene derivatives, in particular, have a high luminescence quantum yield and are therefore preferred. Specific examples of pyrene derivatives include N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-en-9-yl)phenyl]pyrene-1,6-diamine (abbreviated as: 1,6mMemFLPAPrn), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-en-9-yl)phenyl]pyrene-1,6-diamine (abbreviated as: 1,6FLPAPrn), N,N'-bis(dibenzofuran-2-yl)-N,N'-diphenylpyrene-1,6-diamine (abbreviated as: 1,6FrAPrn), and N,N'-bis(dibenzothiophene-2-yl)-N,N' 1,6-diphenylpyrene-1,6-diamine (abbreviated as: 1,6ThAPrn), N,N'-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-6-amine] (abbreviated as: 1,6BnfAPrn), N,N'-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviated as: 1,6BnfAPrn-02), N,N'-(pyrene-1,6-diyl)bis[(6,N-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviated as: 1,6BnfAPrn-03), etc.

[0093] In addition, 5,6-bis[4-(10-phenyl-9-anthrayl)phenyl]-2,2'-bipyridine (abbreviated: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthrayl)biphenyl-4-yl]-2,2'-bipyridine (abbreviated: PAPP2BPy), and N,N'-bis[4-(9H-carbazole-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviated: YGA2S), 4-(9H-carbazole-9-yl)-4'-(10-phenyl-9-anthrayl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazole-9-yl)-4'-(9,10-diphenyl-2-anthrayl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthrayl)phenyl]-9H-carbazole-3-amine (abbreviation: PCAPA), 4-(10) 4-[4-(10-phenyl-9-anthrayl)phenyl]-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCPAPA), 4-[4-(10-phenyl-9-anthrayl)phenyl]-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCPABA), perylene, 2,5,8,11-tetra-(tertiary butyl)perylene (abbreviation: TBP), N,N”-(2-tertiary butyl anthracene-9,10-diyl di- 4,1-Phenylbenzyl)bis[N,N',N'-triphenyl-1,4-phenylenediamine] (abbreviated as: DPABPA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthrayl)phenyl]-9H-carbazole-3-amine (abbreviated as: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthrayl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviated as: 2DPAPPA), etc.

[0094] In addition, N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthrayl]-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCABPhA), N-(9,10-diphenyl-2-anthrayl)-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthrayl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), and 9,10-bis(1,1'-biphenyl-2-yl)-N-[4-(9H-carbazole-9-yl)phenyl]-N-phenylanthracene-2-amine (abbreviation: 2YGAB) can be used. PhA), N,N,9-triphenylanthracene-9-amine (abbreviated: DPhAPhA), coumarin 545T, N,N'-diphenylquinacridone (abbreviated: DPQd), fluorene, 5,12-bis(1,1'-biphenyl-4-yl)-6,11-diphenyltetraphenyl (abbreviated: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]vinyl}-6-methyl-4H-pyran-4-ylidene)malonitrile (abbreviated: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinazin-9-yl)vinyl]-4H-pyran-4-ylidene}malonitrile (abbreviated: DCM2), N,N,N' N'-Tetra(4-methylphenyl)tetraphenyl-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetra(4-methylphenyl)acenaphthene[1,2-a]propadiene-3,10-diamine (abbreviation: p-mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinazin-9-yl)vinyl]-4H-pyran-4-ylidene}malonium (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]]quinazin-9-yl)vinyl]-4H-pyran-4-ylidene}malonium (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]] Quinazine-9-yl)vinyl]-4H-pyran-4-ylidene}malonium (abbreviation: DCJTB), 2-(2,6-bis{2-[4-(dimethylamino)phenyl]vinyl}-4H-pyran-4-ylidene)malonium (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinazine-9-yl)vinyl]-4H-pyran-4-ylidene}malonium (abbreviation: BisDCJTM), 1,6BnfAPrn-03, 3,10-bis[N-(9-phenyl-9H-carbazol-2-yl)-N-phenylamino]naphtho[2,3-b;[6,7-b']bisbenzofuran (abbreviated as: 3,10PCA2Nbf(IV)-02), 3,10-bis[N-(dibenzofuran-3-yl)-N-anilino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviated as: 3,10FrA2Nbf(IV)-02), etc. In particular, pyrene diamine compounds such as 1,6FLPAPrn, 1,6mMemFLPAPrn, and 1,6BnfAPrn-03 can be used.

[0095] <<Converting triple excitation energy into luminescent materials>> Next, as a light-emitting material that can be used in the light-emitting layer 113 to convert triple excitation energy into light emission, examples include materials that emit phosphorescence (phosphorescent materials) or materials that exhibit thermally activated delayed fluorescence (TADF).

[0096] Phosphorescent materials are compounds that emit phosphorescence but not fluorescence at any temperature within a range above low temperature (e.g., 77 K) and below room temperature (i.e., above 77 K and below 313 K). Preferably, the phosphorescent material contains a metallic element with strong spin-orbit interactions, such as organometallic complexes, metal complexes (platinum complexes), rare-earth metal complexes, etc. Specifically, it is preferred to contain a transition metal element, especially platinum group elements (ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), or platinum (Pt)), and particularly preferably iridium. Iridium is preferred because it increases the probability of direct transitions between the singlet ground state and the triplet excited state.

[0097] <<Phosphorescent materials (450nm and above, 570nm and below: blue or green)>> Examples of phosphorescent substances that exhibit blue or green color and whose emission spectrum has a peak wavelength of 450 nm or higher and 570 nm or lower include the following substances.

[0098] For example, examples include tri{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN 2]phenyl-κC}iridium(III) (abbreviated as: [Ir(mpptz-dmp) 3]), tri(5-methyl-3,4-diphenyl-4H-1,2,4-triazole)iridium(III) (abbreviated as: [Ir(Mptz) 3]), tri[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazole]iridium(III) (abbreviated as: [Ir(iPrptz-3b) 3]), and tri[3-(5-biphenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazole]iridium(III) (abbreviated as: [Ir(iPr5btz)). Organometallic complexes with 4H-triazole rings, such as tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazole]iridium(III) (abbreviated as [Ir(Mptz1-mp)3]), tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazole)iridium(III) (abbreviated as [Ir(Prptz1-Me)3]), etc.; organometallic complexes with 1H-triazole rings, such as fac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazolium]iridium(III) (abbreviated as [Ir(iPrpmi)3]), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviated as [Ir(dmpimpt-Me)] Organometallic complexes with imidazole rings, such as bis[2-(4',6'-difluorophenyl)pyridinium-N,C 2']iridium(III)tetra(1-pyrazolyl)borate (abbreviated as: FIr6), bis[2-(4',6'-difluorophenyl)pyridinium-N,C 2']iridium(III)pyridinecarboxylate (abbreviated as: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinium-N,C 2'}iridium(III)pyridinecarboxylate (abbreviated as: [Ir(CF 3ppy) 2(pic)]), bis[2-(4',6'-difluorophenyl)pyridinium-N,C 2']iridium(III)acetone (abbreviated as: FIr(acac)), etc., which use phenylpyridine derivatives with electron-withdrawing groups as ligands.

[0099] <<Phosphorescent materials (495nm and above, but below 590nm: green or yellow)>> Examples of phosphorescent substances that exhibit green or yellow color and whose emission spectrum has a peak wavelength of 495 nm or higher and 590 nm or lower include the following substances.

[0100] Examples include tris(4-methyl-6-phenylpyrimidine)iridium(III) (abbreviated as [Ir(mppm) 3]), tris(4-tert-butyl-6-phenylpyrimidine)iridium(III) (abbreviated as [Ir(tBuppm) 3]), (acetylacetone)bis(6-methyl-4-phenylpyrimidine)iridium(III) (abbreviated as [Ir(mppm) 2(acac)]), (acetylacetone)bis(6-tert-butyl-4-phenylpyrimidine)iridium(III) (abbreviated as [Ir(tBuppm) 2(acac)]), and (acetylacetone)bis[6-(2-norborneol)-4-phenylpyrimidine]iridium(III) (abbreviated as [Ir(nbppm)]). Organometallic iridium complexes with pyrimidine rings, such as 2(acac)]), (acetylacetone)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidine]iridium(III) (abbreviated as: [Ir(mpmppm) 2(acac)]), (acetylacetone)bis{4,6-dimethyl-2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN3]phenyl-κC}iridium(III) (abbreviated as: [Ir(dmppm-dmp) 2(acac)]), (acetylacetone)bis(4,6-diphenylpyrimidine)iridium(III) (abbreviated as: [Ir(dppm) 2(acac)]), and (acetylacetone)bis(4,6-diphenylpyrimidine)iridium(III) (abbreviated as: [Ir(mppr-Me)]); (acetylacetone)bis(3,5-dimethyl-2-phenylpyrazine)iridium(III) (abbreviated as: [Ir(mppr-Me)]); Organometallic iridium complexes with pyrazine rings, such as [Ir(mppr-iPr) 2(acac)] and (acetylene acetone)bis(5-isopropyl-3-methyl-2-phenylpyrazine)iridium(III) (abbreviated as: [Ir(mppr-iPr) 2(acac)]).Tris(2-phenylpyridinium-N,C 2')iridium(III) (abbreviated as: [Ir(ppy) 3]), bis(2-phenylpyridinium-N,C 2')iridium(III)acetoacetone (abbreviated as: [Ir(ppy) 2(acac)]), bis(benzo[h]quinoline)iridium(III)acetoacetone (abbreviated as: [Ir(bzq) 2(acac)]), tris(benzo[h]quinoline)iridium(III) (abbreviated as: [Ir(bzq) 3]), tris(2-phenylquinoline-N,C 2')iridium(III) (abbreviated as: [Ir(pq) 3]), bis(2-phenylquinoline-N,C 2')iridium(III)acetoacetone (abbreviated as: [Ir(pq) 3]), bis(2-phenylquinoline-N,C 2')iridium(III)acetoacetone (abbreviated as: [Ir(pq) 3]) 2(acac)]), bis[2-(2-pyridyl-κN)phenyl-κC][2-(4-phenyl-2-pyridyl-κN)phenyl-κC]iridium(III) (abbreviated as: [Ir(ppy) 2(4dppy)]), bis[2-(2-pyridyl-κN)phenyl-κC][2-(4-methyl-5-phenyl-2-pyridyl-κN)phenyl-κC], [2-d3-methyl-8-(2-pyridyl-κN)benzofuran[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridyl-κN2)phenyl-κC]iridium(III) (abbreviated as: Ir(5mppy-d3) 2(mbfpypy-d3)), [2-(methyl-d3)-8-[4-(1-methylethyl-1-d)-2-pyridinyl-κN]benzofurano[2,3-b]pyridin-7-yl-κC]bis[5-(methyl-d3)-2-[5-(methyl-d3)-2-pyridinyl-κN]phenyl-κC]iridium(III) (abbreviation: Ir(5mtpy-d6) 2(mbfpypy-iPr-d4)), [2-d3-methyl-(2-pyridinyl-κN)benzofurano[2,3-b]pyridinyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: Ir(ppy) Organometallic iridium complexes with pyridine rings, such as 2(mbfpypy-d3)) and [2-(4-methyl-5-phenyl-2-pyridyl-κN)phenyl-κC]bis[2-(2-pyridyl-κN)phenyl-κC]iridium(III) (abbreviated as: Ir(ppy) 2(mdppy));Organometallic complexes such as bis(2,4-diphenyl-1,3-acetazol-N,C 2')iridium(III)acetoacetone (abbreviated as: [Ir(dpo) 2(acac)]), bis{2-[4'-(perfluorophenyl)phenyl]pyridine-N,C 2'}iridium(III)acetoacetone (abbreviated as: [Ir(p-PF-ph) 2(acac)]), bis(2-phenylbenzothiazole-N,C 2')iridium(III)acetoacetone (abbreviated as: [Ir(bt) 2(acac)]), and rare earth metal complexes such as tri(acetoacetone-(monoporphyrin) terbium(III) (abbreviated as: [Tb(acac) 3(Phen)]).

[0101] <<Phosphorescent materials (570nm and above, but below 750nm: yellow or red)>> Examples of phosphorescent substances that exhibit yellow or red color and whose emission spectrum has a peak wavelength of 570 nm or higher and 750 nm or lower include the following substances.

[0102] For example, organometallic complexes with pyrimidine rings such as (diisobutylmethane)bis[4,6-bis(3-methylphenyl)pyrimidinium]iridium(III) (abbreviated as: [Ir(5mdppm) 2(dibm)]), (bis[4,6-bis(3-methylphenyl)pyrimidinium](dineopentylmethane)iridium(III) (abbreviated as: [Ir(5mdppm) 2(dpm)]), and (dineopentylmethane)bis[4,6-di(naphthyl-1-yl)pyrimidinium]iridium(III) (abbreviated as: [Ir(d1npm) 2(dpm)]) can be cited; and (acetylacetone)bis(2,3,5-triphenylpyrazine)iridium(III) (abbreviated as: [Ir(tppr)]) can be cited. 2(acac)]), bis(2,3,5-triphenylpyrazine)(dineoptidomylmethane)iridium(III) (abbreviated as: [Ir(tppr) 2(dpm)]), bis{4,6-dimethyl-2-[3-(3,5-dimethylphenyl)-5-phenyl-2-pyrazinyl-κN]phenyl-κC}(2,6-dimethyl-3,5-heptanedione-κ 2O,O')iridium(III) (abbreviated as: [Ir(dmdppr-P) 2(dibm)]), bis{4,6-dimethyl-2-[5-(4-cyano-2,6-dimethylphenyl)-3-(3,5-dimethylphenyl)-2-pyrazinyl-κN]phenyl-κC}(2,2,6,6-tetramethyl-3,5-heptanedione-κ 2O,O')iridium(III) (abbreviated as: [Ir(dmdppr-dmCP) 2(dpm)]), bis[2-(5-(2,6-dimethylphenyl)-3-(3,5-dimethylphenyl)-2-pyrazinyl-κN)-4,6-dimethylphenyl-κC](2,2',6,6'-tetramethyl-3,5-heptanedione-κ 2O,O')iridium(III) (abbreviated as: [Ir(dmdppr-dmp) 2(dpm)]), (acetylacetone)bis[2-methyl-3-phenylquinoxalinato]-N,C 2']iridium(III) (abbreviated as: [Ir(mpq) 2(acac)]), (acetylacetone)bis(2,3-diphenylquinoxalinato)-N,C Organometallic complexes with pyrazine rings, such as [Ir(dpq)2(acac)] and (acetoacetone)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (Ir(Fdpq)2(acac)];Organometallic complexes having a pyridine ring such as tris(1-phenylisoquinoline-N,C2’)iridium(III) (abbreviation: [Ir(piq)3]), bis(1-phenylisoquinoline-N,C2’)iridium(III) acetylacetonate (abbreviation: [Ir(piq)2(acac)]), bis[4,6-dimethyl-2-(2-quinolin-κN)phenyl-κC](2,4-pentanedionato-κ2O,O’)iridium(III) (abbreviation: [Ir(dmpqn)2(acac)]); platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine platinum(II) (abbreviation: [PtOEP]); or rare earth metal complexes such as tris(1,3-diphenyl-1,3-propanedionato(monophenanthroline)europium(III) (abbreviation: [Eu(DBM)3(Phen)]), tris[1-(2-thiophenecarbonyl)-3,3,3-trifluoroacetone](monophenanthroline)europium(III) (abbreviation: [Eu(TTA)3(Phen)]).;

[0103] <<TADF material>> In addition, as the TADF material, the following materials can be used. The TADF material refers to a material in which the energy difference between the S1 energy level and the T1 energy level is small (preferably 0.2 eV or less) and can convert the triplet excited state to the singlet excited state (reverse intersystem crossing) using minute thermal energy and emit light (fluorescence) from the singlet excited state with high efficiency. The conditions for obtaining thermally activated delayed fluorescence with high efficiency are as follows: the energy difference between the triplet excited energy level and the singlet excited energy level is 0 eV or more and 0.2 eV or less, preferably 0 eV or more and 0.1 eV or less. The delayed fluorescence emitted by the TADF material refers to light emission having the same spectrum as ordinary fluorescence but a very long lifetime. Its lifetime is 1×10-6 seconds or more, preferably 1×10-3 seconds or more.

[0104] Examples of TADF materials include fullerenes or their derivatives, acridine derivatives such as proflavin, and eosin. Additionally, examples include metallic violets containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd). Examples of metallic violet compounds include, for example, protoviolet-tin fluoride complex (SnF 2(Proto IX)), mesoviolet-tin fluoride complex (SnF 2(Meso IX)), hematoviolet-tin fluoride complex (SnF 2(Hemato IX)), tetramethyl copropisyl ester-tin fluoride complex (SnF 2(Copro III-4Me)), octaethylviolet-tin fluoride complex (SnF 2(OEP)), protoviolet-tin fluoride complex (SnF 2(Etio I)), and octaethylviolet-platinum chloride complex (PtCl 2OEP).

[0105] [Chemical Formula 3]

[0106] In addition to the above, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazole-11-yl)-1,3,5-triazine (abbreviated as: PIC-TRZ), 2-{4-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated as: PCCzPTzn), 2-[4-(1 OH-[4-(5-phenyl-5,10-dihydrophenanthrene-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenanthrene-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-oxanthracene-9-one (abbreviation: ACRXTN), bis... [4-(9,9-dimethyl-9,10-dihydroacrylidine)phenyl] ion (abbreviation: DMAC-DPS), 10-phenyl-10H,10'H-spiro[acrylidine-9,9'-anthracene]-10'-one (abbreviation: ACRSA), 4-(9'-phenyl-3,3'-bi-9H-carbazole-9-yl)benzofurano[3,2-d]pyrimidine (abbreviation: 4PCCzBfpm), 4-[4-(9'-phenyl] Heteroaromatic compounds, including π-electron-rich and π-electron-deficient heteroaromatic compounds, are such as 4PCCzPBfpm (3,3'-bi-9H-carbazole-9-yl)phenyl]benzofuran[3,2-d]pyrimidine and 9-[3,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole and mPCCzPTzn-02.

[0107] Furthermore, in substances where π-electron-rich and π-electron-deficient heteroaromatic compounds are directly bonded, the π-electron-rich heteroaromatic compounds exhibit strong donor properties, while the π-electron-deficient heteroaromatic compounds show strong acceptor properties, resulting in a smaller energy difference between the singlet and triplet excited states. Additionally, TADF materials in thermal equilibrium between the singlet and triplet excited states (TADF100) can also be used as TADF materials. Due to their short luminescence lifetime (excitation lifetime), this type of TADF material can suppress efficiency degradation in the high-brightness regions of the light-emitting element.

[0108] [Chemical Formula 4]

[0109] In addition to the above, nanostructures of transition metal compounds with perovskite structures can be cited as materials capable of converting triple excitation energy into luminescence. Metal halide perovskite nanostructures are particularly preferred. Nanoparticles and nanorods are preferred as such nanostructures.

[0110] In the luminescent layers (113, 113a, 113b, 113c), one or more organic compounds (host materials, etc.) that combine the above-mentioned luminescent substances (guest materials) can be used as the basis for the composition of the organic compounds (host materials).

[0111] <<Fluorescent Main Material>> When the luminescent material used in the luminescent layers (113, 113a, 113b, 113c) is a fluorescent luminescent material, the organic compound (host material) used in combination with the luminescent material is preferably an organic compound with a high energy level of its singlet excited state and a low energy level of its triplet excited state, or an organic compound with a high fluorescence quantum yield. Therefore, any organic compound that meets the above conditions can be used, such as the hole transport material (described above) or the electron transport material (described later) shown in this embodiment.

[0112] Although some of the content repeats the specific examples mentioned above, from the viewpoint that it is better to use it in combination with luminescent substances (fluorescent substances), examples of fused polycyclic aromatic compounds as organic compounds (host materials) include anthracene derivatives, fused tetrabenzene derivatives, phenanthrene derivatives, pyrene derivatives, chrysene derivatives, and dibenzo[g,p]chrysene derivatives.

[0113] Specific examples of organic compounds (host materials) preferably used in combination with fluorescent materials include 9-phenyl-3-[4-(10-phenyl-9-anthrayl)phenyl]-9H-carbazole (abbreviated: PCzPA), 3,6-diphenyl-9-[4-(10-phenyl-9-anthrayl)phenyl]-9H-carbazole (abbreviated: DPCzPA), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviated: PCPN), 9,10-diphenylanthracene (abbreviated: DPAN), N,N-diphenyl-9-[4-(10-phenyl-9-anthrayl)phenyl]-9H-carbazole-3-amine (abbreviated: CzA1PA), and 4-(10-phenyl-9-anthrayl)triamine. Aniline (abbreviated as DPhPA), YGAPA, PCAPA, N,9-diphenyl-N-{4-[4-(10-phenyl-9-anthrayl)phenyl]phenyl}-9H-carbazole-3-amine (abbreviated as PCAPBA), N-(9,10-diphenyl-2-anthrayl)-N,9-diphenyl-9H-carbazole-3-amine (abbreviated as 2PCAPA), 6,12-dimethoxy-5,11-diphenylamine, N,N,N',N',N”,N”,N”',N”'-octaphenyldibenzo[g,p]phenyl-2,7,10,15-tetraamine (abbreviated as DBC1), 9-[4-(10-phenyl-9-anthrayl)phenyl]-9H-carbazole (abbreviated as CzPA), 7-[4-( 10-Phenylacetyl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthrayl)phenyl]-benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-{4-(9-phenyl-9H-furo-9-yl)biphenyl-4'-yl}anthracene (abbreviation: FLPPA), 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 9,10-bis(2-naphthyl)anthracene (abbreviation: DNA), 2-tert-butyl-9,10-bis(2-naphthyl)anthracene (abbreviation: t-BuDNA), 9-(1-naphthyl)-10-(2-naphthyl)anthracene (abbreviation: α,β-ADN), 2-(10-phenylanthracene-9-yl)dibenzofuran, 2-(10-phenyl-9-anthrayl)-benzo[b]naphtho[2,3-d]furan (abbreviation: Bnf(II)PhA), 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth), 9-(2-naphthyl)-10-[3-(2-naphthyl)phenyl]anthracene (abbreviation: βN-mβNPAnth), 1-[4-(10-[1,1'-biphenyl]-4-yl-9-anthrayl)phenyl]-2-ethyl-1H-benzimidazole (abbreviation: EtBImPBPhA), 9,9'-bianthracene (abbreviation: BANT), 9,9'-(stilbene-3,3'-Diyl)diphenanthrene (abbreviated as DPNS), 9,9'-(stilbene-4,4'-diyl)diphenanthrene (abbreviated as DPNS2), 1,3,5-tris(1-pyrene)benzene (abbreviated as TPB3), 5,12-diphenyltetraphenyl, 5,12-bis(biphenyl-2-yl)tetraphenyl, etc.

[0114] <<Phosphorescent Host Materials>> When the luminescent material used for the luminescent layers (113, 113a, 113b, 113c) is a phosphorescent luminescent material, the organic compound (host material) used in combination with the luminescent material should be an organic compound whose triple excitation energy (the energy difference between the ground state and the triple excited state) is greater than the triple excitation energy of the luminescent material. Note that when multiple organic compounds (e.g., a first host material and a second host material (or also called auxiliary materials)) are used in combination with the luminescent material to form an excited-state complex, it is preferable to use these multiple organic compounds mixed with the phosphorescent luminescent material.

[0115] By employing such a structure, luminescence via ExTET (Exciplex-Triplet Energy Transfer), which utilizes energy transfer from excited-state complexes to luminescent materials, can be efficiently obtained. As a combination of multiple organic compounds, it is preferable to use a combination that readily forms excited-state complexes, particularly a combination of compounds that readily accept holes (hole-transporting materials) and compounds that readily accept electrons (electron-transporting materials).

[0116] Although some content repeats the specific examples mentioned above, from the viewpoint of optimal combination with luminescent substances (phosphorescent substances), examples of organic compounds (main materials and auxiliary materials) include aromatic amines (organic compounds with an aromatic amine skeleton), carbazole derivatives (organic compounds with a carbazole ring), dibenzothiophene derivatives (organic compounds with a dibenzothiophene ring), dibenzofuran derivatives (organic compounds with a dibenzofuran ring), acediazole derivatives (organic compounds with an acediazole ring), triazole derivatives (organic compounds with a triazole ring), and benzimidazole derivatives. Zazole derivatives (organic compounds with a benzimidazole ring), quinoline derivatives (organic compounds with a quinoline ring), dibenzoquinoline derivatives (organic compounds with a dibenzoquinoline ring), pyrimidine derivatives (organic compounds with a pyrimidine ring), triazine derivatives (organic compounds with a triazine ring), pyridine derivatives (organic compounds with a pyridine ring), bipyridine derivatives (organic compounds with a bipyridine ring), phenoline derivatives (organic compounds with a phenoline ring), furandiazine derivatives (organic compounds with a furandiazine ring), zinc or aluminum metal complexes, etc.

[0117] Note that among the above-mentioned organic compounds, specific examples of aromatic amines and carbazole derivatives that are organic compounds with high hole transport properties can be given as materials that are the same as the specific examples of hole transport materials mentioned above, and these materials are preferably used as host materials.

[0118] Furthermore, specific examples of dibenzothiophene derivatives and dibenzofuran derivatives, which are organic compounds with high hole transport properties among the aforementioned organic compounds, include 4-{3-[3-(9-phenyl-9H-en-9-yl)phenyl]phenyl}dibenzofuran (abbreviated as mmDBFFLBi-II), 4,4',4”-(phenyl-1,3,5-triyl)tris(dibenzofuran) (abbreviated as DBF3P-II), and DBT3P-I. Materials such as 1, 2,8-diphenyl-4-[4-(9-phenyl-9H-furo-9-yl)phenyl]dibenzothiophene (abbreviated as: DBTFLP-III), 4-[4-(9-phenyl-9H-furo-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviated as: DBTFLP-IV), and 4-[3-(triphenyl-2-yl)phenyl]dibenzothiophene (abbreviated as: mDBTPTp-II) are preferred as host materials.

[0119] In addition, other preferred host materials include bis[2-(2-benzothiazolyl)phenol]zinc(II) (abbreviated as ZnPBO) and bis[2-(2-benzothiazolyl)phenol]zinc(II) (abbreviated as ZnBTZ), which are metal complexes with benzothiazolyl ligands and thiazolyl ligands.

[0120] Furthermore, among the aforementioned organic compounds, specific examples of acediazole derivatives, triazole derivatives, benzimidazole derivatives, quinoline derivatives, dibenzoquinoline derivatives, quinazoline derivatives, and phenazolin derivatives, which are organic compounds with high electron transport properties, include 2-(4-biphenyl)-5-(4-tertiary butylphenyl)-1,3,4-acediazole (abbreviated as PBD), 1,3-bis[5-(p-tertiary butylphenyl)-1,3,4-acediazole-2-yl]benzene (abbreviated as OXD-7), 9-[4-(5-phenyl-1,3,4-acediazole-2-yl)phenyl]-9H-carbazole (abbreviated as CO11), and 3-(4-biphenyl)-4-phenyl-5-(4-tertiary butylphenyl)-1, Organic compounds containing heteroaromatic rings with polyazole rings, such as 2,4-triazole (TAZ), 2,2',2”-(1,3,5-benzyltriyl)tris(1-phenyl-1H-benzimidazole) (TPBI), 2-[3-(dibenzothiophene-4-yl)phenyl]-1-phenyl-1H-benzimidazole (mDBTBIm-II), and 4,4'-bis(5-methylbenzoxazo-2-yl)stilbene (BzOS), as well as ruberin (Bphen), copper oxychloride (BCP), 2,9-bis(naphthyl-2-yl)-4,7-diphenyl-1,10-phenerin (NBphen), and 2,2-(1,3-phenylene)bis[9-phenyl-1,10-phenerin] Organic compounds containing heteroaromatic rings with pyridine rings, such as [-phenanthioline] (abbreviated: mPPhen2P), 2,2'-[biphenyl]-4,4'-dimethylbis[1,10-phenanthioline] (abbreviated: Phen2BP), 2-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoline (abbreviated: 2mDBTPDBq-II), 2-[3'-(dibenzothiophene-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoline (abbreviated: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoline (abbreviated: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H- Carbazole-9-yl)phenyl]dibenzo[f,h]quinoline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoline (abbreviation: 7mDBTPDBq-II), 6-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoline (abbreviation: 6mDBTPDBq-II), 2-{4-[9,10-di(2-naphthyl)-2-anthrayl]phenyl}-1-phenyl-1H-benzimidazole (abbreviation: ZADN), 2-[4'-(9-phenyl-9H-carbazole-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoline (abbreviation: 2mpPCBPDBq), etc.These materials are preferred for use as the main body material.

[0121] Among the aforementioned organic compounds, specific examples of pyridine derivatives, diazine derivatives (including pyrimidine derivatives, pyrazine derivatives, and triazine derivatives), triazine derivatives, and furan diazine derivatives, which are organic compounds with high electron transport properties, include 4,6-bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviated as: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothiophene)phenyl]pyrimidine (abbreviated as: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazole-9-yl)phenyl]pyrimidine (abbreviated as: 4,6mCzP2Pm), and 2-{4-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}-4,6-diphenyl-1 3,5-Triazine (abbreviation: PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), 3,5-bis[3-(9H-carbazole-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tris[3-(3-pyridine)phenyl]benzene (abbreviation: TmPyPB), 9,9'-[pyrimidin-4,6-diylbis(biphenyl-3,3'-diyl)]bis(9H-carbazole) (abbreviation: 4,6mCzBP2Pm), 2-[3'-(9,9-dimethyl-9H-furan-2-yl)biphenyl-3-yl]-4,6 -Diphenyl-1,3,5-triazine (abbreviation: mFBPTzn), 8-(1,1'-biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 9-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furano[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 9-[(3'-dibenzothiophen-4-yl)biphenyl-4-yl]naphtho[1',2':4,5]furano[2,3-b]pyrazine (abbreviation: 9pmDBtBPNfpr), 5-[3-(4,6-diphenyl- 1,3,5-Triazine-2-yl)phenyl]-7,7-dimethyl-5H,7H-indo[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 2-[3'-(biphenyl-2-yl)-1,1'-biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mTpBPTzn), 2-[(1,1'-biphenyl)-4-yl]-4-phenyl-6-[9,9'-spirodi(9H-furan)-2-yl]-1,3,5-triazine (abbreviation: BP-SFTzn), 2,6-bis(4-naphthyl-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 9-[4-(4,6-Diphenyl-1,3,5-triazine-2-yl)-2-dibenzothiophene]-2-phenyl-9H-carbazole (abbreviation: PCDBfTzn), 2-[1,1'-biphenyl]-3-yl-4-phenyl-6-(8-[1,1':4',1”-triphenyl]-4-yl-1-dibenzofuranyl)-1,3,5-triazine (abbreviation: mBP-TPDBfTzn), 6-(1,1'-biphenyl) Organic compounds containing heteroaromatic rings with diazine rings, such as 4-[3,5-bis(9H-carbazole-9-yl)phenyl]-2-phenylpyrimidine (abbreviated as: 6mBP-4Cz2PPm) and 4-[3,5-bis(9H-carbazole-9-yl)phenyl]-2-phenyl-6-(1,1'-biphenyl-4-yl)pyrimidine (abbreviated as: 6BP-4Cz2PPm), are preferred as host materials.

[0122] Among the aforementioned organic compounds, specific examples of metal complexes that are organic compounds with high electron transport properties include: tris(8-hydroxyquinoline)aluminum(III) (abbreviated as Alq), tris(4-methyl-8-hydroxyquinoline)aluminum(III) (abbreviated as Almq 3), bis(10-hydroxybenzo[h]quinoline)beryllium(II) (abbreviated as BeBq 2), bis(2-methyl-8-hydroxyquinoline)(4-phenylphenol)aluminum(III) (abbreviated as BAlq), and bis(8-hydroxyquinoline)zinc(II) (abbreviated as Znq); metal complexes having quinoline rings or benzoquinoline rings, etc., and these materials are preferred as host materials.

[0123] In addition, poly(2,5-pyridinediyl) (abbreviated as PPy), poly[(9,9-dihexylenazine-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviated as PF-Py), poly[(9,9-dioctylenazine-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviated as PF-BPy) and other polymeric compounds can also be used as preferred host materials.

[0124] Furthermore, organic compounds with high hole transport and high electron transport include bipolar 9-phenyl-9'-(4-phenyl-2-quinazolinyl)-3,3'-bi-9H-carbazole (abbreviated: PCCzQz), 2-[4'-(9-phenyl-9H-carbazolin-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoline (abbreviated: 2mpPCBPDBq), 5-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-indo[2, Organic compounds with diazine rings, such as 1-b]carbazole (abbreviated as: mINc(II)PTzn), 11-(4-[1,1'-biphenyl]-4-yl-6-phenyl-1,3,5-triazin-2-yl)-11,12-dihydro-12-phenyl-indole[2,3-a]carbazole (abbreviated as: BP-Icz(II)Tzn), and 7-[4-(9-phenyl-9H-carbazole-2-yl)quinazolin-2-yl]-7H-dibenzo[c,g]carbazole (abbreviated as: PC-cgDBCzQz), can also be used as host materials.

[0125] <Electron transport layer> The electron transport layers (114, 114a, 114b) are layers that transport electrons injected from the second electrode 102 or the charge generation layers (106, 106a, 106b) through the electron injection layers (115, 115a, 115b) described later to the light-emitting layers (113, 113a, 113b). Furthermore, the electron transport layers (114, 114a, 114b) are layers containing an electron transport material, preferably the hybrid material for light-emitting devices described in Embodiment 1. As the electron transport material for the electron transport layers (114, 114a, 114b), it is preferably a material having an electron mobility of 1×10⁻⁶ cm² / Vs or higher when the square root of the electric field strength [V / cm] is 600. In addition, any material other than the above-described material can be used as long as its electron transport capability is higher than its hole transport capability. Furthermore, the electron transport layers (114, 114a, 114b) function even as a single layer, but a stacked structure of two or more layers can also be used. Note that because the above-mentioned hybrid materials are heat-resistant, photolithography processes performed on electron transport layers using these hybrid materials can suppress the impact on device characteristics caused by thermal processes.

[0126] <<Electron Transport Materials>> As an electron transport material suitable for use in electron transport layers (114, 114a, 114b), highly electron-transporting organic compounds can be used, such as heteroaromatic compounds. Note that heteroaromatic compounds refer to cyclic compounds containing at least two different elements in the ring. Note that the ring structure includes three-membered, four-membered, five-membered, and six-membered rings, with five-membered or six-membered rings being particularly preferred. The contained elements, besides carbon, are preferably one or more of nitrogen, oxygen, and sulfur in the heteroaromatic compound. Nitrogen-containing heteroaromatic compounds are particularly preferred, and materials with high electron transport properties (electron transport materials) such as nitrogen-containing heteroaromatic compounds or π-electron-deficient heteroaromatic compounds containing such nitrogen-containing heteroaromatic compounds are preferred.

[0127] Heteroaromatic compounds are organic compounds that have at least one heteroaromatic ring.

[0128] Note that the heteroaromatic ring has any one of the following: a pyridine ring, a diazine ring, a triazine ring, a polyazole ring, a thiazolium ring, and a thiazole ring. Furthermore, heteroaromatic rings with a diazine ring include those with a pyrimidine ring, a pyrazine ring, or a diazolium ring. Additionally, heteroaromatic rings with a polyazole ring include those with an imidazole ring, a triazole ring, or a diazole ring.

[0129] Heteroaromatic rings include fused heteroaromatic rings with fused ring structures. Note that examples of fused heteroaromatic rings include quinoline rings, benzoquinoline rings, quinoline rings, dibenzoquinoline rings, quinazoline rings, benzoquinazoline rings, dibenzoquinazoline rings, phenoline rings, furan diazine rings, and benzimidazole rings.

[0130] Note that, as heteroaromatic compounds, for example, heteroaromatic compounds that contain one or more of nitrogen, oxygen, and sulfur in addition to carbon, examples of heteroaromatic compounds having a five-membered ring structure include heteroaromatic compounds having an imidazole ring, heteroaromatic compounds having a triazole ring, heteroaromatic compounds having an acetazole ring, heteroaromatic compounds having an acediazole ring, heteroaromatic compounds having a thiazole ring, and heteroaromatic compounds having a benzimidazole ring.

[0131] For example, among heteroaromatic compounds that contain one or more of nitrogen, oxygen, and sulfur in addition to carbon, examples of heteroaromatic compounds with a six-membered ring structure include heteroaromatic compounds with heteroaromatic rings such as pyridine rings, diazine rings (including pyrimidine rings, pyrazine rings, and triazine rings), triazine rings, and polyazole rings. Note that examples of heteroaromatic compounds with bipyridine structures and heteroaromatic compounds with terpyridine structures are also included, as they are examples of heteroaromatic compounds with pyridine rings.

[0132] Furthermore, examples of heteroaromatic compounds with fused ring structures in which a portion of the aforementioned six-membered ring structure can be categorized as heteroaromatic compounds having fused heteroaromatic rings such as quinoline rings, benzoquinoline rings, quinoline rings, dibenzoquinoline rings, phenoline rings, furan diazine rings (including rings in which the furan ring of the furan diazine ring is fused with an aromatic ring), and benzimidazole rings.

[0133] Specific examples of heteroaromatic compounds having the aforementioned five-membered ring structures (polyazole rings (including imidazole, triazole, and acediazole rings), acediazole, thiazole, and benzimidazole rings, etc.) include 2-(4-biphenyl)-5-(4-tertiary butylphenyl)-1,3,4-acediazole (abbreviated as PBD), 1,3-bis[5-(p-tertiary butylphenyl)-1,3,4-acediazole-2-yl]benzene (abbreviated as OXD-7), 9-[4-(5-phenyl-1,3,4-acediazole-2-yl)phenyl]-9H-carbazole (abbreviated as CO11), and 3-(4-biphenyl)-4-phenyl-5- (4-Tributylphenyl)-1,2,4-triazole (abbreviated as TAZ), 3-(4-tributylphenyl)-4-(4-ethylphenyl)-5-(4-biphenyl)-1,2,4-triazole (abbreviated as p-EtTAZ), 2,2',2”-(1,3,5-phenyltriyl)tris(1-phenyl-1H-benzimidazole) (abbreviated as TPBI), 2-[3-(dibenzothiophene-4)-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviated as mDBTBIm-II), 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviated as BzOS), etc.

[0134] Specific examples of heteroaromatic compounds having the aforementioned six-membered ring structure (including heteroaromatic rings with pyridine, diazine, triazine, etc.) include 3,5-bis[3-(9H-carbazole-9-yl)phenyl]pyridine (abbreviated as: 35DCzPPy) and 1,3,5-tris[3-(3-pyridyl)phenyl]benzene (abbreviated as: TmPyPB), which contain heteroaromatic rings with pyridine rings; 2-{4-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}-4,6-diphenyl-1,3 5-Triazine (abbreviated: PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviated: mPCCzPTzn-02), 5-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-indo[2,1-b]carbazole (abbreviated: mINc(II)PTzn), 2-[3'-(biphenyl-2-yl)-1,1'-biphenyl-3-yl]- 4,6-Diphenyl-1,3,5-triazine (abbreviation: mTpBPTzn), 2-[(1,1'-biphenyl)-4-yl]-4-phenyl-6-[9,9'-spirobi(9H-furan)-2-yl]-1,3,5-triazine (abbreviation: BP-SFTzn), 2,6-bis(4-naphthyl-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 9-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzothiophene]-2- Phenyl-9H-carbazole (abbreviated: PCDBfTzn), 2-[1,1'-biphenyl]-3-yl-4-phenyl-6-(8-[1,1':4',1”-triphenyl]-4-yl-1-dibenzofuranyl)-1,3,5-triazine (abbreviated: mBP-TPDBfTzn), 2-{3-[3-(dibenzothiophene-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated: mDBtBPTzn), mFBPTzn, and other heteroaromatic compounds containing a triazine ring;4,6-Bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothiophene)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazole-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 4,6mCzBP2Pm, 6-(1,1'-biphenyl-3-yl)-4-[3,5-bis(9H-carbazole- 9-yl)phenyl)-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm), 4-[3,5-bis(9H-carbazole-9-yl)phenyl]-2-phenyl-6-(1,1'-biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm), 4-[3-(dibenzothiophene-4-yl)phenyl]-8-(naphthyl)-[1]benzofurano[3,2-d]pyrimidine (abbreviation: 8βN-4mDBtPBfpm), 8B P-4mDBtPBfpm, 9mDBtBPNfpr, 9pmDBtBPNfpr, 3,8-bis[3-(dibenzothiophene-4-yl)phenyl]benzofurano[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 4,8-bis[3-(dibenzothiophene-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviation: 4,8mDBtP2Bfpm), 8-[3'-(dibenzothiophene) -4-yl)(1,1'-biphenyl-3-yl)]naphtho[1',2':4,5]furano[3,2-d]pyrimidine (abbreviation: 8mDBtBPNfpm), 8-[(2,2'-binaphthyl)-6-yl]-4-[3-(dibenzothiophene-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviation: 8(βN2)-4mDBtPBfpm), and other heteroaromatic compounds containing a diazine (pyrimidine) ring, etc. Note that aromatic compounds containing the above-mentioned heteroaromatic rings include heteroaromatic compounds with fused heteroaromatic rings.

[0135] In addition, examples include 2,2'-(pyridin-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviated as: 2,6(P-Bqn)2Py), 2,2'-(2,2'-bispyridin-6,6'-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviated as: 6,6'(P-Bqn)2BPy), 2,2'-(pyridin-2,6-diyl)bis{4-[4-(2-naphthyl)phenyl]-6-phenylpyrimidine} (abbreviated as: 2,6(NP-PPm)2Py), and 6-(1,1'-biphenyl-3-yl)-4-[3,5-bis(9H-carbazole-9-yl)phenyl]-2 Heteroaromatic compounds containing a diazine (pyrimidine) ring, such as phenylpyrimidine (abbreviated as: 6mBP-4Cz2PPm); heteroaromatic compounds containing a triazine ring, such as 2,4,6-tris(3'-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine (abbreviated as: TmPPPyTz), 2,4,6-tris(2-pyridyl)-1,3,5-triazine (abbreviated as: 2Py3Tz), and 2-[3-(2,6-dimethyl-3-pyridyl)-5-(9-phenanthyl)phenyl)-4,6-diphenyl-1,3,5-triazine (abbreviated as: mPn-mDMePyPTzn).

[0136] Specific examples of heteroaromatic compounds (heteroaromatic compounds with fused ring structures) that have a portion of the aforementioned six-membered ring structure include ruberin (abbreviated as Bphen), copper oxychloride (abbreviated as BCP), 2,9-bis(naphthyl-2-yl)-4,7-diphenyl-1,10-phenerin (abbreviated as NBphen), 2,2-(1,3-phenylene)bis[9-phenyl-1,10-phenerin] (abbreviated as mPPhen2P), 2,2'-(pyridin-2,6-diyl)bis(4-phenylbenzo[h]quinazolin) (abbreviated as 2,6(P-Bqn)2Py), 2-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinazolin (abbreviated as 2mDBTPDBq-II), 2-[3'-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinazolin (abbreviated as 2mDBTPDBq-II), and 2-[3'-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinazolin (abbreviated as 2mDBTPDBq-II). Compounds containing a quinoline ring include: 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoline (abbreviated as: 2mDBTBPDBq-II), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoline (abbreviated as: 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoline (abbreviated as: 7mDBTPDBq-II), 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoline (abbreviated as: 6mDBTPDBq-II), 2mpPCBPDBq, and other heteroaromatic compounds.

[0137] In addition to the heteroaromatic compounds mentioned above, the electron transport layers (114, 114a, 114b) can also use the following metal complexes. Examples of such metal complexes include tri(8-hydroxyquinoline)aluminum(III) (abbreviated: Alq 3), Almq 3, lithium(I) of 8-hydroxyquinoline (abbreviated: Liq), BeBq 2, bis(2-methyl-8-hydroxyquinoline)(4-phenylphenol)aluminum(III) (abbreviated: BAlq), bis(8-hydroxyquinoline)zinc(II) (abbreviated: Znq), etc., which have quinoline rings or benzoquinoline rings; bis[2-(2-benzo[ ...

[0138] In addition, as electron transport materials, polymers such as poly(2,5-pyridinediyl) (abbreviated as PPy), poly[(9,9-dihexylfuran-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviated as PF-Py), and poly[(9,9-dioctylfuran-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviated as PF-BPy) can also be used.

[0139] In addition, the electron transport layers (114, 114a, 114b) can be a single layer or a stack of two or more layers containing the aforementioned substances.

[0140] <Electron Injection Layer> The electron injection layers (115, 115a, 115b) are layers containing materials with high electron injection capability. The electron injection layers (115, 115a, 115b) are used to improve the efficiency of electron injection from the second electrode 102, and preferably use materials whose work function value is small (less than 0.5 eV) compared to the LUMO energy level value of the material used for the second electrode 102. Therefore, as the electron injection layers (115, 115a, 115b), alkali metals, alkaline earth metals, or compounds thereof, such as lithium, cesium, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF₂), lithium 8-(hydroxyoxoline) (Liq), lithium 2-(2-pyridyl)phenol (LiPP), lithium 2-(2-pyridyl)-3-hydroxypyridine (LiPPy), lithium 4-phenyl-2-(2-pyridyl)phenol (LiPPP), lithium oxide (LiO₂x), and cesium carbonate, can be used. Furthermore, rare earth metals such as ytterbium (Yb) or rare earth metal compounds such as erbium fluoride (ErF₃) can be used. Note that the electron injection layers (115, 115a, 115b) can be formed by mixing or stacking multiple of the above materials. Alternatively, electron compounds can be used for the electron injection layers (115, 115a, 115b). Examples of electron compounds include mixed oxides of calcium and aluminum that add electrons at high concentrations. Alternatively, substances constituting the electron transport layers (114, 114a, 114b) as described above can also be used.

[0141] Furthermore, a hybrid material consisting of a mixed organic compound and an electron donor (donor) can be used in the electron injection layer (115, 115a, 115b). This hybrid material exhibits excellent electron injection and electron transport properties because it generates electrons in the organic compound through the electron donor. In this case, the organic compound is preferably a material with excellent performance in transporting the generated electrons. Specifically, for example, an electron transport material (metal complex or heteroaromatic compound, etc.) used in the electron transport layer (114, 114a, 114b) as described above can be used. As the electron donor, any substance that provides electrons to the organic compound is acceptable. Specifically, alkali metals, alkaline earth metals, or rare earth metals are preferred, such as lithium, cesium, magnesium, calcium, erbium, and ytterbium. Additionally, alkali metal oxides and alkaline earth metal oxides are preferred, such as lithium oxide, calcium oxide, and barium oxide. Furthermore, Lewisite such as magnesium oxide can also be used. Additionally, organic compounds such as tetrathiofulvalene (TTF) can also be used. Alternatively, multiple of these materials can be used in layers.

[0142] In addition, hybrid materials consisting of mixed organic compounds and metals can also be used for the electron injection layers (115, 115a, 115b). Note that the organic compounds used here are preferably those with a LUMO (Lowest Unoccupied Molecular Orbital) energy level of -3.6 eV to -2.3 eV. Furthermore, non-shared electron pairs are preferred.

[0143] Therefore, as the organic compound used in the above-mentioned mixed material, a mixed material formed by mixing the above-mentioned heteroaromatic compounds that can be used for the electron transport layer with a metal can also be used. The heteroaromatic compounds are preferably heteroaromatic compounds having a five-membered ring structure (imidazolium ring, triazole ring, oxazole ring, oxadiazole ring, thiazole ring, benzimidazole ring, etc.), heteroaromatic compounds having a six-membered ring structure (pyridine ring, diazine ring (including pyrimidine ring, pyrazine ring, pyrazine ring, etc.), triazine ring, bipyridine ring, terpyridine ring, etc.), or heteroaromatic compounds with a partially fused ring structure having a six-membered ring structure (quinoline ring, benzo[a]quinoline ring, quinoline ring, dibenzo[a]quinoline ring, benziline ring, etc.), etc., and other materials with non-shared electron pairs. Specific materials have already been described above, so their description is omitted here.

[0144] As the metal used in the above-mentioned mixed material, it is preferable to use a transition metal belonging to Group 5, Group 7, Group 9 or Group 11 of the periodic table, or a material belonging to Group 13, such as Ag, Cu, Al or In. Furthermore, in this case, a single occupied orbital domain (SOMO) is formed between the organic compound and the transition metal.

[0145] Furthermore, for example, when amplifying the light received from the light-emitting layer 113b, it is preferable to form the light so that the optical distance between the second electrode 102 and the light-emitting layer 113b is less than 1 / 4 of the wavelength λ of the light emitted by the light-emitting layer 113b. In this case, the optical distance can be adjusted by changing the thickness of the electron transport layer 114b or the electron injection layer 115b.

[0146] Furthermore, as shown in Figure 1D, by providing a charge generation layer 106 between two EL layers (103a, 103b), a structure in which multiple EL layers are stacked between a pair of electrodes can be achieved (also known as a series structure).

[0147] <charge generation layer> The charge generation layer 106 functions to inject electrons into the EL layer 103a and holes into the EL layer 103b when a voltage is applied between the first electrode 101 (anode) and the second electrode 102 (cathode). The charge generation layer 106 can have a structure that adds an electron acceptor (acceptor) to the hole-transporting material, or a structure that adds an electron donor (donor) to the electron-transporting material. Alternatively, both structures can be stacked. Note that by using the above-described materials to form the charge generation layer 106, the rise in driving voltage caused by stacking the EL layers can be suppressed.

[0148] When the charge-generating layer 106 has a structure that adds an electron acceptor to the hole-transporting material of the organic compound, the material shown in this embodiment can be used as the hole-transporting material. Furthermore, examples of electron acceptors include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinone dimethane (abbreviated as F4-TCNQ) and chloroquinone. In addition, oxides of metals belonging to Groups 4 to 8 of the periodic table can be used. Specifically, examples include vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide.

[0149] When the charge generation layer 106 has a structure that adds an electron donor to the electron transport material, the material shown in this embodiment can be used as the electron transport material. Furthermore, alkali metals, alkaline earth metals, rare earth metals, or metals belonging to Groups 2 and 13 of the periodic table, as well as their oxides or carbonates, can be used as electron donors. Specifically, lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca), ytterbium (Yb), indium (In), lithium oxide, cesium carbonate, etc., are preferred. In addition, organic compounds such as tetrathianaphthacene can also be used as electron donors.

[0150] Although Figure 1D shows a structure with two stacked EL layers 103, it can be made into a stacked structure with more than three layers by setting charge generation layers between different EL layers.

[0151] <Substrate> The light-emitting device shown in this embodiment can be formed on various substrates. Note that there is no specific limitation on the type of substrate. Examples of such substrates include semiconductor substrates (e.g., single-crystal substrates or silicon substrates), SOI substrates, glass substrates, quartz substrates, plastic substrates, metal substrates, stainless steel substrates, substrates containing stainless steel foil, tungsten substrates, substrates containing tungsten foil, flexible substrates, laminated films, and paper or substrate films containing fibrous materials.

[0152] Examples of glass substrates include barium borosilicate glass, aluminum borosilicate glass, and soda-lime glass. Examples of flexible substrates, laminating films, and base films include plastics such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polyether ether (PES), synthetic resins such as acrylic resins, polypropylene, polyester, ethylene fluoride, polyvinyl chloride, polyamide resins, polyimide resins, aromatic polyamide resins, epoxy resins, inorganic vapor-deposited films, and paper.

[0153] Furthermore, when manufacturing the light-emitting device shown in this embodiment, vapor phase methods such as vapor deposition, liquid phase methods such as spin coating, or inkjet printing can be used. As vapor deposition methods, physical vapor deposition (PVD) methods such as sputtering, ion plating, ion beam vapor deposition, molecular beam vapor deposition, and vacuum vapor deposition, or chemical vapor deposition (CVD) methods can be used. In particular, layers with various functions (hole injection layer 111, hole transport layer 112, light-emitting layer 113, electron transport layer 114, and electron injection layer 115) included in the EL layer of the light-emitting device can be formed using methods such as vapor deposition (vacuum vapor deposition), coating methods (dip coating, dye coating, rod coating, spin coating, spray coating, etc.), and printing methods (inkjet printing, screen printing, lithography, flexographic printing, photogravure printing, micro-contact printing, etc.).

[0154] Note that when using the film-forming methods described above, such as coating and printing, you can use high molecular weight compounds (oligomers, dendritic polymers, polymers, etc.), medium molecular weight compounds (compounds between low and high molecular weight: molecular weight 400 to 4000), and inorganic compounds (quantum dot materials, etc.). Note that as quantum dot materials, you can use colloidal quantum dot materials, alloy-type quantum dot materials, core-shell quantum dot materials, and core-type quantum dot materials, etc.

[0155] The materials of each layer (hole injection layer 111, hole transport layer 112, light emission layer 113, electron transport layer 114, electron injection layer 115) constituting the EL layer 103 of the light-emitting device shown in this embodiment are not limited to the materials shown in this embodiment. Any materials that can satisfy the function of each layer can be used in combination.

[0156] The structure shown in this embodiment can be appropriately combined with the structures shown in other embodiments.

[0157] Implementation Method 3 In this embodiment, a specific structural example and manufacturing method of a light-emitting device (also called a display panel) according to one embodiment of the present invention will be described.

[0158] <Structural Example 1 of Light-emitting Device 700> The light-emitting device 700 shown in Figure 2A includes light-emitting devices 550B, 550G, 550R, and a partition wall 528. Furthermore, the light-emitting devices 550B, 550G, 550R, and the partition wall 528 are formed on a functional layer 520 disposed on a first substrate 510. The functional layer 520 includes driving circuits GD and SD, which are composed of multiple transistors, as well as wiring that electrically connects them. Note that, as an example, these driving circuits are electrically connected to the light-emitting devices 550B, 550G, and 550R, and can drive these devices. Furthermore, the light-emitting device 700 includes an insulating layer 705 on the functional layer 520 and each light-emitting device, and the insulating layer 705 has the function of bonding the second substrate 770 and the functional layer 520. The driving circuits GD and SD will be described in Embodiment 4.

[0159] Note that light-emitting devices 550B, 550G, and 550R have the device structure shown in Embodiment 2. That is, the EL layer 103 in the structure shown in FIG. 1A is shown in different cases in each light-emitting device.

[0160] Furthermore, in this specification and other materials, the structure in which light-emitting devices of different colors (e.g., blue (B), green (G), and red (R)) are formed with light-emitting layers or coated with light-emitting layers separately is sometimes referred to as an SBS (Side By Side) structure.

[0161] As shown in Figure 2A, the light-emitting device 550B includes electrodes 551B and 552, and an EL layer 103B. Note that the specific structure of each layer is as shown in Embodiment 2. Furthermore, the EL layer 103B has a stacked structure composed of multiple layers with different functions, including a light-emitting layer. In Figure 2A, only the hole injection / transport layer 104B, electron transport layer 108B, and electron injection layer 109 are shown among the layers included in the EL layer 103B with the light-emitting layer; however, the present invention is not limited to this. Note that the hole injection / transport layer 104B shows a layer having the functions of the hole injection layer and hole transport layer shown in Embodiment 2, and may also have a stacked structure. Note that in this specification, the hole injection / transport layer in any one of the light-emitting devices can be interpreted as described above.

[0162] The electron transport layer 108B is preferably made of the hybrid material for the light-emitting device shown in Embodiment 1. Note that the hybrid material for the light-emitting device shown in Embodiment 1 includes a first heteroaromatic compound and a second heteroaromatic compound. The first heteroaromatic compound has a first heteroaromatic ring, which includes a ring having two or more nitrogen atoms and either a benzene ring or a pyridine ring, or a diazine ring or a triazine ring. The second heteroaromatic compound has a second heteroaromatic ring, which includes a ring having two or more nitrogen atoms and either a benzene ring or a pyridine ring, or a diazine ring or a triazine ring. The structures of the first and second heteroaromatic rings are different from each other. Note that the electron transport layer 108B may also function to block holes that move from the anode side through the light-emitting layer to the cathode side. Furthermore, the electron injection layer 109 may also have a multilayer structure formed using different materials, either partially or entirely.

[0163] As shown in Figure 2A, an insulating layer 107 can also be formed on the side (or end) of the hole injection / transport layer 104B, the light-emitting layer, and the electron transport layer 108B in the EL layer 103B, which includes the light-emitting layer. The insulating layer 107 is formed in contact with the side (or end) of the EL layer 103B. This suppresses the entry of oxygen, moisture, or substances containing oxygen or moisture constituent elements into the interior from the side of the EL layer 103B. Note that the insulating layer 107 can be made of, for example, aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon nitride, or silicon oxynitride. Furthermore, the insulating layer 107 can be formed by laminating the above-mentioned materials. The insulating layer 107 can be formed using sputtering, CVD, MBE, PLD, ALD, etc., with ALD, which offers good coverage, being preferred.

[0164] In addition, a portion of the EL layer 103B (including the light-emitting layer, the hole injection / transport layer 104B, and the electron transport layer 108B) and the insulating layer 107 form an electron injection layer 109. Note that the electron injection layer 109 may also have a stacked structure of two or more layers with different resistances.

[0165] Electrode 552 is formed on electron injection layer 109. Note that electrodes 551B and 552 have overlapping regions. Furthermore, an EL layer 103B is included between electrodes 551B and 552.

[0166] The EL layer 103B shown in Figure 2A has the same structure as the EL layer 103 described in Embodiment 2. Furthermore, the EL layer 103B can, for example, emit blue light.

[0167] As shown in Figure 2A, the light-emitting device 550G includes electrodes 551G, 552, and an EL layer 103G. Note that the specific structure of each layer is as shown in Embodiment 2. Furthermore, the EL layer 103G has a stacked structure composed of multiple layers with different functions, including a light-emitting layer. In Figure 2A, only the hole injection / transport layer 104G, the electron transport layer 108G, and the electron injection layer 109 are shown among the layers included in the EL layer 103G with the light-emitting layer; however, the present invention is not limited to these. Note that the hole injection / transport layer 104G shows a layer having the functions of the hole injection layer and the hole transport layer shown in Embodiment 2, and may also have a stacked structure.

[0168] The electron transport layer 108G is preferably made of the hybrid material for the light-emitting device shown in Embodiment 1. Note that the hybrid material for the light-emitting device shown in Embodiment 1 includes a first heteroaromatic compound and a second heteroaromatic compound. The first heteroaromatic compound has a first heteroaromatic ring, which includes a ring having two or more nitrogen atoms and either a benzene ring or a pyridine ring, or a ring having a diazine ring or a triazine ring. The second heteroaromatic compound has a second heteroaromatic ring, which includes a ring having two or more nitrogen atoms and either a benzene ring or a pyridine ring, or a ring having a diazine ring or a triazine ring. The structures of the first and second heteroaromatic rings are different from each other. Note that the electron transport layer 108G may also function to block holes that move from the anode side through the light-emitting layer to the cathode side. Furthermore, the electron injection layer 109 may also have a multilayer structure formed using different materials, either partially or entirely.

[0169] As shown in Figure 2A, an insulating layer 107 can also be formed on the sides (or ends) of the hole injection / transport layer 104G, the light-emitting layer, and the electron transport layer 108G included in the EL layer 103G, which includes the light-emitting layer. The insulating layer 107 is formed in contact with the sides (or ends) of the EL layer 103G. This suppresses the entry of oxygen, moisture, or their constituent elements from the sides of the EL layer 103G into the interior. Note that the insulating layer 107 can be made of, for example, aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon nitride, or silicon oxynitride. Furthermore, the insulating layer 107 can be formed by laminating the above-mentioned materials. The insulating layer 107 can be formed using sputtering, CVD, MBE, PLD, ALD, etc., with ALD, which offers good coverage, being preferred.

[0170] In addition, a portion of the EL layer 103G (including the light-emitting layer, the hole injection / transport layer 104G, and the electron transport layer 108G) and the insulating layer 107 form an electron injection layer 109. Note that the electron injection layer 109 may also have a stacked structure of two or more layers with different resistances in the layers.

[0171] Electrode 552 is formed on electron injection layer 109. Note that electrodes 551G and 552 have overlapping regions. Furthermore, an EL layer 103G is included between electrodes 551G and 552.

[0172] The EL layer 103G shown in Figure 2A has the same structure as the EL layer 103 described in Embodiment 2. Furthermore, the EL layer 103G can, for example, emit green light.

[0173] As shown in Figure 2A, the light-emitting device 550R includes electrodes 551R, 552, and an EL layer 103R. Note that the specific structure of each layer is as shown in Embodiment 2. Furthermore, the EL layer 103R has a stacked structure composed of multiple layers with different functions, including a light-emitting layer. In Figure 2A, only the hole injection / transport layer 104R, the electron transport layer 108R, and the electron injection layer 109 are shown among the layers included in the EL layer 103R with the light-emitting layer; however, the present invention is not limited to these. Note that the hole injection / transport layer 104R shows a layer having the functions of the hole injection layer and the hole transport layer shown in Embodiment 2, and may also have a stacked structure.

[0174] The electron transport layer 108R is preferably made of the hybrid material for the light-emitting device shown in Embodiment 1. Note that the hybrid material for the light-emitting device shown in Embodiment 1 includes a first heteroaromatic compound and a second heteroaromatic compound. The first heteroaromatic compound has a first heteroaromatic ring, which includes a ring having two or more nitrogen atoms and either a benzene ring or a pyridine ring, or a ring having a diazine ring or a triazine ring. The second heteroaromatic compound has a second heteroaromatic ring, which includes a ring having two or more nitrogen atoms and either a benzene ring or a pyridine ring, or a ring having a diazine ring or a triazine ring. The structures of the first and second heteroaromatic rings are different from each other. Note that the electron transport layer 108R may also function to block holes that move from the anode side through the light-emitting layer to the cathode side. Furthermore, the electron injection layer 109 may also have a multilayer structure formed using different materials, either partially or entirely.

[0175] As shown in Figure 2A, an insulating layer 107 can also be formed on the sides (or ends) of the hole injection / transport layer 104R, the light-emitting layer, and the electron transport layer 108R included in the EL layer 103R, which includes the light-emitting layer. The insulating layer 107 is formed in contact with the sides (or ends) of the EL layer 103R. This can suppress the entry of oxygen, moisture, or their constituent elements from the sides of the EL layer 103R into the interior. Note that the insulating layer 107 can be made of, for example, aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon nitride, or silicon oxynitride. Furthermore, the insulating layer 107 can be formed by laminating the above-mentioned materials. The insulating layer 107 can be formed using sputtering, CVD, MBE, PLD, ALD, etc., and is preferably formed using the ALD method, which has good coverage.

[0176] In addition, a portion of the covering EL layer 103R (including the light-emitting layer, the hole injection / transport layer 104R, and the electron transport layer 108R) and the insulating layer 107 form an electron injection layer 109. Note that the electron injection layer 109 may also have a stacked structure of two or more layers with different resistances in the layers.

[0177] Electrode 552 is formed on electron injection layer 109. Note that electrodes 551R and 552 have overlapping regions. Furthermore, an EL layer 103R is included between electrodes 551R and 552.

[0178] The EL layer 103R shown in Figure 2A has the same structure as the EL layer 103 described in Embodiment 2. Furthermore, the EL layer 103R can, for example, emit red light.

[0179] A partition wall 528 is included between EL layers 103B, EL layers 103G, and EL layers 103R. Note that, as shown in Figure 2A, the sides (or ends) of the EL layers (EL layers 103B, EL layers 103G, and EL layers 103R) of each light-emitting device are in contact with the partition wall 528 through an insulating layer 107.

[0180] In each EL layer, the hole injection layer, which is formed as a shared layer in adjacent light-emitting devices, sometimes causes crosstalk because of its high conductivity, especially in the hole transport region located between the anode and the light-emitting layer. Therefore, as shown in this structural example, crosstalk between adjacent light-emitting devices can be suppressed by providing a partition wall 528 made of insulating material between each EL layer.

[0181] In the manufacturing method described in this embodiment, the side (or end) of the EL layer is exposed midway through the patterning process. Therefore, the EL layer is prone to deterioration due to the intrusion of oxygen or water from the side (or end) of the EL layer. Therefore, by providing the partition wall 528, the deterioration of the EL layer during the manufacturing process can be suppressed.

[0182] By providing the partition wall 528, the recesses formed between adjacent light-emitting devices can be planarized. Furthermore, by planarizing the recesses, the disconnection of the electrodes 552 formed on each EL layer can be suppressed. Additionally, as the insulating material used to form the partition wall 528, organic materials such as acrylic resin, polyimide resin, epoxy resin, imide resin, polyimide resin, polyimide-polyamide resin, silicone resin, silicone resin, benzocyclobutene resin, phenolic resin, and precursors of these resins can be used. Furthermore, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerol, pullulan, water-soluble cellulose, or polyimide resins soluble in alcohols can also be used. Additionally, photosensitive resins such as photoresists can be used. Note that the photosensitive resin can be either a positive or negative material.

[0183] The difference between the height of the top surface of the partition wall 528 and the height of the top surface of any one of the EL layers 103B, 103G, and 103R is preferably less than 0.5 times the thickness of the partition wall 528, and more preferably less than 0.3 times. Alternatively, for example, the insulating layer may be provided such that the top surface of any one of the EL layers 103B, 103G, and 103R is higher than the top surface of the partition wall 528. Furthermore, for example, the top surface of the partition wall 528 may be higher than the top surface of the light-emitting layer included in the EL layers 103B, 103G, and 103R.

[0184] In high-definition light-emitting devices (display panels) with a resolution exceeding 1000 ppi, crosstalk occurs when electrical conduction occurs between EL layers 103B, EL layers 103G, and EL layers 103R, thus narrowing the color gamut that the light-emitting device can display. By incorporating partition walls 528 in high-definition display panels with a resolution exceeding 1000 ppi, preferably high-definition display panels with a resolution exceeding 2000 ppi, and more preferably ultra-high-definition display panels with a resolution exceeding 5000 ppi, a display panel capable of displaying vibrant colors can be provided.

[0185] Figure 2B shows a top view of the light-emitting device 700 corresponding to the dashed lines Ya-Yb in the cross-sectional view of Figure 2A. That is, light-emitting devices 550B, 550G, and 550R are all arranged in a matrix. Note that Figure 2B shows a so-called strip arrangement of light-emitting devices of the same color in the X direction. Furthermore, light-emitting devices of different colors are arranged in the Y direction, which intersects the X direction. Note that the arrangement of the light-emitting devices is not limited to this; arrangements such as Delta arrangement, zigzag arrangement, Pentile arrangement, and Diamond arrangement can also be used.

[0186] Note that since photolithography is used to form patterns during the separation processing of each EL layer (EL layer 103B, EL layer 103G, and EL layer 103R), a high-definition light-emitting device (display panel) can be manufactured. Furthermore, the ends (sides) of the EL layers processed using photolithography have a shape that is substantially the same surface (or, located on substantially the same plane). Additionally, the width (SE) of the gap 580 between each EL layer is preferably 5 μm or less, more preferably 1 μm or less.

[0187] In the EL layer, due to the high conductivity of the hole injection layer, especially in the hole transport region located between the anode and the light-emitting layer, the hole injection layer, which is formed as a layer shared by adjacent light-emitting devices, sometimes causes crosstalk. Therefore, as shown in this structural example, crosstalk between adjacent light-emitting devices can be suppressed by performing patterning using photolithography to separate the EL layer.

[0188] Figure 2C is a cross-sectional view corresponding to the dashed line C1-C2 in Figure 2B. Figure 2C shows the connection portion 130 that electrically connects electrode 551C and electrode 552. In the connection portion 130, electrode 552 is disposed on and in contact with electrode 551C. Furthermore, a partition wall 528 is provided to cover the end of electrode 551C.

[0189] <Example 1 of manufacturing method for light-emitting device> As shown in Figure 3A, electrodes 551B, 551G, and 551R are formed. For example, a conductive film is formed on the functional layer 520 formed on the first substrate 510, and the conductive film is processed into a specified shape using photolithography.

[0190] Note that conductive films can be formed using methods such as sputtering, chemical vapor deposition (CVD), molecular beam epitaxy (MBE), vacuum evaporation, pulsed laser deposition (PLD), and atomic layer deposition (ALD). CVD methods include plasma-enhanced chemical vapor deposition (PECVD) and thermal CVD. Additionally, metal-organic chemical vapor deposition (MOCVD) is one example of a thermal CVD method.

[0191] In addition to the photolithography method mentioned above, conductive films can also be processed using nanoimprinting, sandblasting, and peeling methods. Furthermore, island-shaped films can be directly formed using shadow masking methods such as metal masks.

[0192] Photolithography typically employs two methods. One involves forming a photoresist mask on the film to be processed, processing the film by etching, and then removing the photoresist mask. The other involves forming a photosensitive film, followed by exposure and development to process the film into the desired shape. Note that the former method involves heat treatment processes such as pre-applied bake (PAB) and post-exposure bake (PEB). In one embodiment of the present invention, photolithography is also used in the processing of the film used to form the EL layer (a film formed of an organic compound or a film in which a portion of the film contains an organic compound), in addition to the processing of the conductive film.

[0193] In photolithography, the light used for exposure can be, for example, i-line (wavelength 365nm), g-line (wavelength 436nm), h-line (wavelength 405nm), or a mixture of these. Additionally, ultraviolet light, KrF lasers, or ArF lasers can be used. Furthermore, immersion exposure techniques can be employed. Extreme ultraviolet (EUV) light or X-rays can also be used as the light for exposure. Electron beams can also be used instead of the light used for exposure. When using EUV light, X-rays, or electron beams, extremely fine processing can be achieved, making them preferable. Note that when exposure is performed by scanning with a beam such as an electron beam, a photomask is not required.

[0194] As a thin-film etching process using photoresist masks, dry etching, wet etching, sandblasting, and other methods can be employed.

[0195] Next, as shown in FIG3B, an EL layer 103B is formed on electrodes 551B, 551G, and 551R. In FIG3B, the EL layer 103B is formed onto the hole injection / transport layer 104B, the light-emitting layer, and the electron transport layer 108B. For example, the EL layer 103B is formed on electrodes 551B, 551G, and 551R in a manner that covers them using a vacuum evaporation method. Then, a sacrificial layer 110B is formed on the EL layer 103B.

[0196] The sacrificial layer 110B can be a film with high resistance to etching of the EL layer 103B, that is, a film with a relatively large etching selectivity. Furthermore, the sacrificial layer 110B is preferably a stacked structure of a first sacrificial layer and a second sacrificial layer with different etching selectivities. Additionally, the sacrificial layer 110B can be a film that can be removed by wet etching with minimal damage to the EL layer 103B. Oxalic acid or similar materials can be used as etching materials for wet etching.

[0197] As the sacrificial layer 110B, an inorganic film such as a metal film, alloy film, metal oxide film, semiconductor film, or inorganic insulating film can be used. In addition, the sacrificial layer 110B can be formed by various film formation methods such as sputtering, vapor deposition, CVD, and ALD.

[0198] As the sacrificial layer 110B, for example, metallic materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, and tantalum, or alloys containing such metallic materials, can be used. In particular, low-melting-point materials such as aluminum or silver are preferred.

[0199] Alternatively, metal oxides such as indium gallium zinc oxide (In-Ga-Zn oxide, also denoted as IGZO) can be used as the sacrificial layer 110B. Other options include indium oxide, indium zinc oxide (In-Zn oxide), indium tin oxide (In-Sn oxide), indium titanium oxide (In-Ti oxide), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), and indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide). Alternatively, silicon-containing indium tin oxide can also be used.

[0200] Note that element M (selected from one or more of aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium) can also be used instead of gallium. In particular, M is preferably selected from one or more of gallium, aluminum, and yttrium.

[0201] In addition, inorganic insulating materials such as alumina, hafnium oxide, and silicon oxide can be used as the sacrificial layer 110B.

[0202] As the sacrificial layer 110B, it is preferable to use a material that is soluble in a solvent, that is, a solvent that is chemically stable at least relative to the uppermost film (electron transport layer 108B) of the EL layer 103B. In particular, a material soluble in water or alcohol can be suitably used as the sacrificial layer 110B. When forming the sacrificial layer 110B, it is preferable to apply the material by the aforementioned wet deposition method while the material is dissolved in a solvent such as water or alcohol, and then perform a heat treatment to evaporate the solvent. In this case, by performing the heat treatment under a reduced pressure atmosphere, the solvent can be removed at a low temperature in a short time, thus reducing thermal damage to the EL layer 103B, which is preferable.

[0203] Note that when the sacrificial layer 110B is a laminated structure, the layer formed by the above-mentioned material can be used as the first sacrificial layer, and a second sacrificial layer can be formed on it to form a laminated structure.

[0204] At this point, the second sacrificial layer is the film used as a hard mask during the etching of the first sacrificial layer. Furthermore, the first sacrificial layer is exposed during the processing of the second sacrificial layer. Therefore, a combination of films with a relatively large etching selectivity is selected as the first and second sacrificial layers. Thus, a film suitable for the second sacrificial layer can be selected based on the etching conditions of both the first and second sacrificial layers.

[0205] For example, when dry etching using a fluorine-containing gas (also known as a fluorine-based gas) is used as the second sacrificial layer, silicon, silicon nitride, silicon oxide, tungsten, titanium, molybdenum, tantalum, tantalum nitride, alloys containing molybdenum and niobium, or alloys containing molybdenum and tungsten can be used as the second sacrificial layer. Here, metal oxide films such as IGZO and ITO can be used as the first sacrificial layer, as they offer greater etching selectivity (i.e., a slower etching rate) compared to the aforementioned dry etching using fluorine-based gases.

[0206] Furthermore, not limited to this, the second sacrificial layer can be selected from various materials depending on the etching conditions of both the first and second sacrificial layers. For example, it can also be selected from films that can be used for the first sacrificial layer described above.

[0207] Alternatively, a nitride film can be used as the second sacrificial layer. Specifically, nitrides of silicon nitride, aluminum nitride, hafnium nitride, titanium nitride, tantalum nitride, tungsten nitride, gallium nitride, germanium nitride, etc., can also be used.

[0208] Alternatively, an oxide film can be used as the second sacrificial layer. Typically, oxide films or oxynitride films such as silicon oxide, silicon oxynitride, aluminum oxide, aluminum oxynitride, hafnium oxide, and hafnium oxynitride can be used.

[0209] Next, as shown in Figure 3C, a photoresist is coated onto the sacrificial layer 110B, and the photoresist is shaped into the desired form (photoresist mask: REG) using photolithography. Furthermore, this method involves heat treatment processes such as pre-applied bake (PAB) and post-exposure bake (PEB). For example, the PAB temperature is approximately 100°C, and the PEB temperature is approximately 120°C. Therefore, it is necessary to realize a light-emitting device capable of withstanding these processing temperatures. Specifically, in one embodiment of the present invention, the light-emitting device uses a heat-resistant layer formed from a composite material for light-emitting devices, as described in Embodiment 1, which is used to expose the layer to photolithography treatment. This suppresses the effects of heat treatment, thus providing a light-emitting device including a highly reliable light-emitting device.

[0210] Next, a portion of the sacrificial layer 110B not covered by the photoresist mask REG is removed by etching using the obtained photoresist mask REG. Then, a portion of the EL layer 103B not covered by the sacrificial layer 110B is removed by etching. The EL layers 103B on electrodes 551G and 551R are also removed by etching, resulting in a shape with sides (or exposed sides) or a strip shape extending in a direction intersecting the paper surface. Specifically, dry etching is performed using the sacrificial layer 110B, which has a pattern formed on the EL layer 103B overlapping with electrode 551B. Alternatively, if the sacrificial layer 110B has the aforementioned stacked structure of the first and second sacrificial layers, the photoresist mask REG can be removed after etching a portion of the second sacrificial layer, and the second sacrificial layer can be used as a mask to etch a portion of the first sacrificial layer, thus processing the EL layer 103B into a predetermined shape. By performing these etching processes, the shape shown in FIG4A is obtained.

[0211] Next, as shown in FIG4B, an EL layer 103G is formed on the sacrificial layer 110B, electrode 551G, and electrode 551R. In FIG4B, a hole injection / transport layer 104G, a light-emitting layer, and an electron transport layer 108G are formed, which are included in the EL layer 103G. For example, the EL layer 103G is formed on the sacrificial layer 110B, electrode 551G, and electrode 551R in a manner that covers them using a vacuum evaporation method.

[0212] Next, as shown in FIG4C, a sacrificial layer 110G is formed on the EL layer 103G, and a photoresist is coated on the sacrificial layer 110G. The photoresist is formed into a desired shape (photoresist mask: REG) by photolithography. A portion of the sacrificial layer 110G not covered by the obtained photoresist mask is removed by etching, and the photoresist mask is removed. Then, a portion of the EL layer 103G not covered by the sacrificial layer 110G is removed by etching. The EL layer 103G on electrode 551B and electrode 551R are removed by etching, and processed into a shape with sides (or exposed sides) or a strip shape extending in a direction intersecting the paper plane, as shown in FIG5A. In addition, when the sacrificial layer 110G has the above-described stacked structure of the first sacrificial layer and the second sacrificial layer, the photoresist mask can be removed after etching a portion of the second sacrificial layer using the photoresist mask, and the second sacrificial layer can be used as a mask to etch a portion of the first sacrificial layer, and the EL layer 103G is processed into a predetermined shape.

[0213] Next, as shown in FIG5B, an EL layer 103R is formed on the sacrificial layers 110B, 110G, and electrode 551R. In FIG5B, a hole injection / transport layer 104R, a light-emitting layer, and an electron transport layer 108R are formed, including the EL layer 103R. For example, the EL layer 103R is formed on the sacrificial layers 110B, 110G, and electrode 551R in a manner that covers them using a vacuum evaporation method.

[0214] Next, as shown in FIG5C, a sacrificial layer 110R is formed on the EL layer 103R, and a photoresist is coated on the sacrificial layer 110R. The photoresist is formed into a desired shape (photoresist mask: REG) by photolithography. A portion of the sacrificial layer 110R not covered by the obtained photoresist mask is removed by etching, and the photoresist mask is removed. Then, a portion of the EL layer 103R not covered by the sacrificial layer 110R is removed by etching. The EL layer 103R on electrode 551B and electrode 551G are removed by etching, and processed into a shape with sides (or exposed sides) or a strip shape extending in a direction intersecting the paper plane. Alternatively, if the sacrificial layer 110G has the above-described stacked structure of the first sacrificial layer and the second sacrificial layer, the photoresist mask can be removed after etching a portion of the second sacrificial layer using the photoresist mask, and the second sacrificial layer can be used as a mask to etch a portion of the first sacrificial layer, and the EL layer 103G is processed into a predetermined shape. Furthermore, sacrificial layers (110B, 110G, 110R) are left on the EL layers (103B, 103G, 103R), and an insulating layer 107 is formed on the sacrificial layers (110B, 110G, 110R) to obtain the shape shown in Figure 6A.

[0215] Furthermore, the insulating layer 107 can be formed, for example, using the ALD method. In this case, as shown in FIG6A, the insulating layer 107 is formed in contact with the sides of each EL layer (103B, 103G, 103R). This prevents oxygen, moisture, or their constituent elements from penetrating into the interior from the sides of each EL layer (103B, 103G, 103R). Materials used in the insulating layer 107 can be, for example, aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon nitride, or silicon oxynitride.

[0216] Next, as shown in Figure 6B, after removing the sacrificial layers (110B, 110G, 110R), an electron injection layer 109 is formed on the insulating layers (107B, 107G, 107R) and the EL layers (103B, 103G, 103R). The electron injection layer 109 is formed, for example, by vacuum evaporation. Additionally, the electron injection layer 109 is formed on the electron transport layers (108B, 108G, 108R). Furthermore, the electron injection layer 109 is in contact with the sides (or ends) of each EL layer (103B, 103G, 103R) (Note that the EL layers (103B, 103G, 103R) shown in Figure 6B include the hole injection / transport layers (104R, 104G, 104B), the light-emitting layer, and the electron transport layers (108B, 108G, 108R)) through an insulating layer (107B, 107G, 107R).

[0217] Next, as shown in FIG6C, electrode 552 is formed. Electrode 552 is formed, for example, by vacuum evaporation. Note that electrode 552 is formed on electron injection layer 109. Note that electrode 552 is in contact with the sides (or ends) of each EL layer (103B, 103G, 103R) through electron injection layer 109 and insulating layers (107B, 107G, 107R) (note that the EL layers (103B, 103G, 103R) shown in FIG6C include hole injection / transport layers (104R, 104G, 104B), light-emitting layers, and electron transport layers (108B, 108G, 108R)). This prevents short circuits between each EL layer (103B, 103G, 103R) and electrode 552. More specifically, it prevents short circuits between the hole injection / transport layers (104B, 104G, 104R) included in each EL layer (103B, 103G, 103R) and electrode 552.

[0218] The above process can be used to separate and process the EL layers 103B, EL layers 103G and EL layers 103R in the light-emitting devices 550B, 550G and 550R.

[0219] Note that since photolithography is used to form patterns in the separation process of these EL layers (EL layer 103B, EL layer 103G, and EL layer 103R), high-definition light-emitting devices (display panels) can be manufactured. Furthermore, the ends (sides) of the EL layers processed using photolithography have a shape that is substantially the same surface (or, located on substantially the same plane).

[0220] In the EL layer, due to the high conductivity of the hole injection layer, especially in the hole transport region located between the anode and the light-emitting layer, the hole injection layer, which is formed as a layer shared by adjacent light-emitting devices, sometimes causes crosstalk. Therefore, as shown in this structural example, crosstalk between adjacent light-emitting devices can be suppressed by performing patterning using photolithography to separate the EL layer.

[0221] <Structural Example 2 of Light-Emitting Device 700> The light-emitting device 700 shown in Figure 7 includes light-emitting devices 550B, 550G, 550R, and a partition wall 530. Furthermore, the light-emitting devices 550B, 550G, 550R, and the partition wall 530 are formed on a functional layer 520 disposed on the first substrate 510. The functional layer 520 includes driving circuits GD and SD, which are composed of multiple transistors, as well as wiring that electrically connects them. Note that, as an example, these driving circuits are electrically connected to the light-emitting devices 550B, 550G, and 550R, and can drive these devices. Furthermore, the driving circuits GD and SD are described in Embodiment 4.

[0222] Note that light-emitting devices 550B, 550G, and 550R have the device structure shown in Embodiment 2. In particular, the different cases of EL layer 103 in the structure shown in FIG1A are shown in each light-emitting device.

[0223] Note that the specific structures of the light-emitting devices shown in Figure 7 are the same as those of light-emitting devices 550B, 550G, and 550R as described in Figures 2A and 2B.

[0224] As shown in Figure 7, the EL layer (103B, 103G, 103R) of each light-emitting device (550B, 550G, 550R) includes a hole injection / transport layer (104B, 104G, 104R), an electron transport layer (108B, 108G, 108R), and an electron injection layer 109.

[0225] Furthermore, since each EL layer (EL layer 103B, EL layer 103G and EL layer 103R) of this structure is patterned using photolithography during the separation process, the ends (sides) of the processed EL layers become shapes with approximately the same surface (or, located on approximately the same plane).

[0226] Each light-emitting device includes an EL layer (EL layer 103B, EL layer 103G, and EL layer 103R) with a gap 580 between adjacent light-emitting devices. Note that here, when the distance between the EL layers of the light-emitting devices adjacent to the gap 580 is denoted as SE, a smaller distance SE improves the aperture ratio and sharpness. On the other hand, a larger distance SE allows for greater tolerance to the effects of process variations between adjacent light-emitting devices, thus improving manufacturing cost efficiency. Since the light-emitting devices manufactured according to this specification are preferably used in miniaturization processes, the distance SE between the EL layers of adjacent light-emitting devices can be 0.5 μm or more and 5 μm or less, preferably 1 μm or more and 3 μm or less, more preferably 1 μm or more and 2.5 μm or less, and even more preferably 1 μm or more and 2 μm or less. Note that the distance SE is typically preferably 1 μm or more and 2 μm or less (e.g., 1.5 μm or nearby).

[0227] In the EL layer, due to the high conductivity of the hole injection layer, especially in the hole transport region located between the anode and the light-emitting layer, the hole injection layer, which is formed as a layer shared by adjacent light-emitting devices, sometimes causes crosstalk. Therefore, as shown in this structural example, crosstalk between adjacent light-emitting devices can be suppressed by performing patterning using photolithography to separate the EL layer.

[0228] In this specification, etc., devices manufactured using a metal mask or FMM (Fine Metal Mask) are sometimes referred to as MM (Metal Mask) structure devices. Furthermore, in this specification, devices manufactured without a metal mask or FMM are referred to as MML (Metal Mask Less) structure devices.

[0229] The structure shown in this embodiment can be appropriately combined with the structures shown in other embodiments.

[0230] Implementation Method 4 In this embodiment, a light-emitting device according to one embodiment of the present invention will be described with reference to FIGS. 8A to 10B. Note that the light-emitting device 700 shown in FIGS. 8A to 10B includes the light-emitting device shown in Embodiment 2. Furthermore, since the light-emitting device 700 described in this embodiment can be used in the display section of electronic devices, etc., it can also be referred to as a display panel.

[0231] The light-emitting device 700 described in this embodiment includes a display area 231 as shown in FIG8A, and the display area 231 includes a group of pixels 703(i,j). In addition, as shown in FIG8B, there is a group of pixels 703(i+1,j) that include adjacent groups of pixels 703(i,j).

[0232] Note that pixel 703(i,j) can use multiple pixels. For example, multiple pixels can be used to display colors with different hues. Note that each of the multiple pixels can be referred to as a subpixel. Alternatively, multiple subpixels can be grouped together and referred to as a pixel.

[0233] Therefore, additive or subtractive color mixing can be performed on the colors displayed by these multiple pixels. Additionally, colors with hues that cannot be displayed by individual pixels can be shown.

[0234] Specifically, the pixel 702B(i,j) that displays blue, the pixel 702G(i,j) that displays green, and the pixel 702R(i,j) that displays red can be used for pixel 703(i,j). Furthermore, each of pixels 702B(i,j), 702G(i,j), and 702R(i,j) can be referred to as a sub-pixel.

[0235] Alternatively, pixels that display white or other colors can be added to the above group and used for pixel 703(i,j). Furthermore, each of the pixels that display cyan, magenta, and yellow can be used as a sub-pixel for pixel 703(i,j).

[0236] In addition to the group mentioned above, pixels that emit infrared light can also be used for pixels 703(i,j). Specifically, pixels that emit light containing wavelengths of 650 nm or more and 1000 nm or less can be used for pixels 703(i,j).

[0237] The display area 231 shown in Figure 8A is surrounded by drive circuits GD and SD. It also includes terminals 519 that are electrically connected to drive circuits GD and SD. Terminals 519 can, for example, be electrically connected to a flexible printed circuit FPC1.

[0238] Note that the driving circuit GD has the function of supplying a first selection signal and a second selection signal. For example, the driving circuit GD is electrically connected to the conductive films G1(i) and G2(i) described later and supplies the first selection signal and the second selection signal respectively. The driving circuit SD has the function of supplying image signals and control signals, and the control signals have a first level and a second level. For example, the driving circuit SD is electrically connected to the conductive films S1g(j) and S2g(j) described later and supplies the image signal and the control signal respectively.

[0239] Figure 10A shows a cross-sectional view of the light-emitting device along the dashed lines X1-X2 and X3-X4 in Figure 8A, respectively. As shown in Figure 10A, the light-emitting device 700 includes a functional layer 520 between the first substrate 510 and the second substrate 770. In addition to the aforementioned driving circuits GD and SD, the functional layer 520 also includes wiring that electrically connects them. Figure 10A shows the structure of the functional layer 520 including pixel circuits 530B(i,j), pixel circuits 530G(i,j), and driving circuit GD, but is not limited to this structure.

[0240] The pixel circuits included in the functional layer 520 (e.g., pixel circuits 530B(i,j) and 530G(i,j) shown in FIG. 10A) are electrically connected to the light-emitting devices formed on the functional layer 520 (e.g., light-emitting devices 550B(i,j) and 550G(i,j) shown in FIG. 10A). Specifically, light-emitting device 550B(i,j) is electrically connected to pixel circuit 530B(i,j) through opening 591B, and light-emitting device 550G(i,j) is electrically connected to pixel circuit 530G(i,j) through opening 591G. In addition, an insulating layer 705 is provided on the functional layer 520 and each light-emitting device, and the insulating layer 705 has the function of bonding the second substrate 770 to the functional layer 520.

[0241] Note that the second substrate 770 can be a substrate with touch sensors arranged in a matrix. For example, a substrate including an electrostatic capacitive touch sensor or an optical touch sensor can be used as the second substrate 770. Thus, the light-emitting device of one embodiment of the present invention can be used as a touch panel.

[0242] Figure 9A shows the specific structure of pixel circuit 530G(i,j).

[0243] As shown in Figure 9A, the pixel circuit 530G(i,j) includes switch SW21, switch SW22, transistor M21, capacitor C21, and node N21. Additionally, the pixel circuit 530G(i,j) includes node N22, capacitor C22, and switch SW23.

[0244] The transistor M21 includes a gate electrode electrically connected to node N21, a first electrode electrically connected to the light-emitting device 550G(i,j), and a second electrode electrically connected to the conductive film ANO.

[0245] The switch SW21 includes a first terminal electrically connected to node N21, a second terminal electrically connected to conductive film S1g(j), and has the function of controlling the on state or the off state according to the potential of conductive film G1(i).

[0246] The switch SW22 includes a first terminal electrically connected to the conductive film S2g(j) and has the function of controlling the on state or the off state according to the potential of the conductive film G2(i).

[0247] Capacitor C21 includes a conductive film electrically connected to node N21 and a conductive film electrically connected to the second electrode of switch SW22.

[0248] Therefore, the image signal can be stored in node N21. Additionally, the potential of node N21 can be changed using switch SW22. Furthermore, the intensity of the light emitted by the light-emitting device 550G(i,j) can be controlled using the potential of node N21.

[0249] Next, Figure 9B shows an example of the specific structure of the transistor M21 illustrated in Figure 9A. Note that, as transistor M21, a bottom-gate transistor or a top-gate transistor, etc., can be appropriately used.

[0250] The transistor shown in Figure 9B includes a semiconductor film 508, a conductive film 504, an insulating film 506, a conductive film 512A, and a conductive film 512B. The transistor is formed, for example, on an insulating film 501C. Additionally, the transistor includes an insulating film 516 (insulating films 516A and 516B) and an insulating film 518.

[0251] The semiconductor film 508 includes a region 508A electrically connected to the conductive film 512A and a region 508B electrically connected to the conductive film 512B. The semiconductor film 508 also includes a region 508C between regions 508A and 508B.

[0252] The conductive film 504 includes a region overlapping with region 508C, and the conductive film 504 functions as a gate electrode.

[0253] The insulating film 506 includes a region sandwiched between the semiconductor film 508 and the conductive film 504. The insulating film 506 functions as a first gate insulating film.

[0254] The conductive film 512A has one of the functions of a source electrode and a drain electrode, and the conductive film 512B has the other of the functions of a source electrode and a drain electrode.

[0255] Alternatively, the conductive film 524 can be used for a transistor. The conductive film 524 includes a region in which a semiconductor film 508 is sandwiched between it and the conductive film 504. The conductive film 524 functions as a second gate electrode. An insulating film 501D is sandwiched between the semiconductor film 508 and the conductive film 524 and functions as a second gate insulating film.

[0256] The insulating film 516 is used, for example, as a protective film covering the semiconductor film 508. Specifically, for example, a film containing silicon oxide film, silicon oxynitride film, silicon oxynitride film, silicon nitride film, aluminum oxide film, hafnium oxide film, yttrium oxide film, zirconium oxide film, gallium oxide film, tantalum oxide film, magnesium oxide film, lanthanum oxide film, cerium oxide film, or neodymium oxide film can be used as the insulating film 516.

[0257] For example, it is preferable to use a material capable of suppressing the diffusion of oxygen, hydrogen, water, alkali metals, alkaline earth metals, etc., in the insulating film 518. Specifically, as the insulating film 518, silicon nitride, silicon oxynitride, aluminum nitride, aluminum oxynitride, etc., can be used, for example. Furthermore, as silicon oxynitride and aluminum oxynitride, it is preferable that the number of nitrogen atoms is greater.

[0258] In the process of forming the semiconductor film of the transistor for the pixel circuit, a semiconductor film for the transistor of the driving circuit can also be formed. For example, the semiconductor film can be used in the driving circuit, and this semiconductor film has the same composition as the semiconductor film in the transistor of the pixel circuit.

[0259] Furthermore, semiconductors containing Group 14 elements can be used in semiconductor film 508. Specifically, semiconductors containing silicon can be used in semiconductor film 508.

[0260] Furthermore, hydrogenated amorphous silicon can be used in the semiconductor film 508. Alternatively, microcrystalline silicon or the like can be used in the semiconductor film 508. Thus, for example, a light-emitting device with less display non-uniformity can be provided compared to a light-emitting device (or display panel) using polycrystalline silicon in the semiconductor film 508. Alternatively, the size of the light-emitting device can be easily increased.

[0261] Furthermore, polycrystalline silicon can be used in the semiconductor film 508. This allows, for example, a higher field-effect mobility than that achieved with a transistor using hydrogenated amorphous silicon in the semiconductor film 508. Furthermore, for example, a higher driving capability than that achieved with a transistor using hydrogenated amorphous silicon in the semiconductor film 508 can be achieved. Alternatively, for example, a higher pixel aperture ratio than that achieved with a transistor using hydrogenated amorphous silicon in the semiconductor film 508 can be achieved.

[0262] Alternatively, for example, higher reliability can be achieved than that of transistors using hydrogenated amorphous silicon in semiconductor film 508.

[0263] Alternatively, for example, the temperature required to manufacture the transistor can be lower than that required for a transistor made of single-crystal silicon.

[0264] Alternatively, the semiconductor film for the transistor used in the driving circuit and the semiconductor film for the transistor used in the pixel circuit can be formed using the same process. Alternatively, the driving circuit can be formed on the same substrate as the substrate on which the pixel circuit is formed. Alternatively, the number of components constituting the electronic device can be reduced.

[0265] Furthermore, monocrystalline silicon can be used in the semiconductor film 508. This allows, for example, a higher resolution than that achieved with hydrogenated amorphous silicon in the semiconductor film 508. Alternatively, for example, it allows for a light-emitting device with less display uniformity compared to a device using polycrystalline silicon in the semiconductor film 508. Alternatively, it allows for the provision of smart glasses or head-mounted displays.

[0266] Furthermore, metal oxides can be used in the semiconductor film 508. This extends the time the pixel circuit can maintain the image signal compared to pixel circuits using transistors with amorphous silicon in the semiconductor film. Specifically, flicker can be suppressed, and a selection signal can be supplied at a frequency below 30Hz, preferably below 1Hz, and more preferably below 1 time / minute. As a result, eye fatigue for users of electronic devices can be reduced. Additionally, power consumption for driving can be reduced.

[0267] In addition, oxide semiconductors can be used in semiconductor film 508. Specifically, oxide semiconductors containing indium, oxide semiconductors containing indium, gallium and zinc, or oxide semiconductors containing indium, gallium, zinc and tin can be used in semiconductor film 508.

[0268] By using oxide semiconductors in semiconductor films, transistors with lower leakage current in the off state can be obtained compared to transistors using amorphous silicon in semiconductor films. Therefore, it is preferable to use transistors using oxide semiconductors in semiconductor films as switches, etc. Note that circuits using transistors using oxide semiconductors in semiconductor films as switches can maintain the potential of the floating node for a longer period of time compared to circuits using transistors using amorphous silicon in semiconductor films as switches.

[0269] Although Figure 10A shows a light-emitting device with a structure that extracts light from the second substrate 770 side (top-emitting type), a light-emitting device with a structure that extracts light from the first substrate 510 side (bottom-emitting type), as shown in Figure 10B, can also be used. Note that in the bottom-emitting type light-emitting device, the first electrode 101 is used as a semi-transmissive-semi-reflective electrode, and the second electrode 102 is used as a reflective electrode.

[0270] Although Figures 10A and 10B illustrate an active matrix type light-emitting device, the structure of the light-emitting device shown in Embodiment 2 can also be used in the passive matrix type light-emitting device shown in Figures 11A and 11B.

[0271] Figure 11A is a perspective view showing a passive matrix type light-emitting device, and Figure 11B is a cross-sectional view along line XY in Figure 11A. In Figures 11A and 11B, electrodes 952 and 956 are disposed on a substrate 951, and an EL layer 955 is disposed between electrodes 952 and 956. The end of electrode 952 is covered by an insulating layer 953. An isolation layer 954 is disposed on the insulating layer 953. The sidewalls of the isolation layer 954 have an inclination such that the spacing between one sidewall and the other sidewall becomes narrower as it approaches the substrate surface. That is, the cross-section of the isolation layer 954 in the short side direction is trapezoidal, and the bottom side (the side facing the same direction as the surface direction of the insulating layer 953 and in contact with the insulating layer 953) is shorter than the top side (the side facing the same direction as the surface direction of the insulating layer 953 and not in contact with the insulating layer 953). Thus, by providing the isolation layer 954, malfunctions of the light-emitting device caused by static electricity, etc., can be prevented.

[0272] The structure shown in this embodiment can be used in appropriate combinations with the structures shown in other embodiments.

[0273] Implementation Method 5 In this embodiment, the structure of an electronic device according to one embodiment of the present invention will be described with reference to FIGS. 12A to 14B.

[0274] Figures 12A to 14B are diagrams illustrating the structure of an electronic device according to one embodiment of the present invention. Figure 12A is a block diagram of the electronic device, and Figures 12B to 12E are perspective views illustrating the structure of the electronic device. Figures 13A to 13E are perspective views illustrating the structure of the electronic device. Figures 14A and 14B are perspective views illustrating the structure of the electronic device.

[0275] The electronic device 5200B described in this embodiment includes an arithmetic unit 5210 and an input / output unit 5220 (see Figure 12A).

[0276] The computing device 5210 has the function of being supplied with operating data and the function of supplying image data according to the operating data.

[0277] The input / output device 5220 includes a display unit 5230, an input unit 5240, a detection unit 5250, and a communication unit 5290, and has the functions of supplying operation data and receiving image data. Furthermore, the input / output device 5220 has the functions of supplying detection data, supplying communication data, and receiving communication data.

[0278] The input unit 5240 has the function of supplying operation data. For example, the input unit 5240 supplies operation data according to the operation of the user of the electronic device 5200B.

[0279] Specifically, keyboards, hardware buttons, pointing devices, touch sensors, illuminance sensors, camera devices, audio input devices, gaze input devices, posture detection devices, etc., can be used in the input section 5240.

[0280] The display unit 5230 includes a display panel and has the function of displaying image data. For example, the display panel described in Embodiment 2 can be used in the display unit 5230.

[0281] The testing unit 5250 has the function of supplying testing data. For example, it has the function of supplying testing data using the environment surrounding the testing electronic device.

[0282] Specifically, illuminance sensors, camera devices, posture detection devices, pressure sensors, human body sensors, etc., can be used in the detection unit 5250.

[0283] The communications unit 5290 has the function of supplying communications data and the function of supplying communications data. For example, it has the function of connecting with other electronic devices or communications networks via wireless or wired communications. Specifically, it has the functions of wireless local area network communications, telephone communications, and short-range wireless communications.

[0284] Figure 12B shows an electronic device having an outline along a cylindrical column or the like. As an example, a digital signage unit could be cited. The display panel of one embodiment of the present invention can be used in the display unit 5230. Note that it may also have a function to change the display method according to the illumination of the usage environment. Furthermore, it may have a function to sense the presence of a human body and change the displayed content. Therefore, it can be installed, for example, on a column of a building. Alternatively, it can display advertisements or guides.

[0285] Figure 12C illustrates an electronic device with the function of generating image data based on the trajectory of an indicator used by the user. Examples include electronic blackboards, electronic message boards, and digital signage. Specifically, a display panel with a diagonal length of 20 inches or more, preferably 40 inches or more, and more preferably 55 inches or more can be used. Alternatively, multiple display panels can be arranged to form a single display area. Alternatively, multiple display panels can be arranged to form a multi-screen display panel.

[0286] Figure 12D illustrates an electronic device that can receive data from other devices and display it on the display unit 5230. Wearable electronic devices can be cited as an example. Specifically, several options can be displayed, or the user can select several options and reply to the sender of the data. Furthermore, for example, it has a function to change the display method according to the ambient light level. This, for example, can reduce the power consumption of the wearable electronic device. Additionally, for example, it can display images on the wearable electronic device in a way that allows for suitable use even in environments with strong external light, such as outdoors on a sunny day.

[0287] Figure 12E illustrates an electronic device including a display section 5230 that curves gently along the side of the casing. A mobile phone is an example. Furthermore, the display section 5230 includes a display panel, which, for example, has the function of displaying on its front, sides, top, and back. Thus, for example, data can be displayed not only on the front of the phone, but also on its sides, top, and back.

[0288] Figure 13A illustrates an electronic device that can receive data from the Internet and display it on a display unit 5230. A smartphone can be cited as an example. For instance, notifications can be viewed on the display unit 5230. Furthermore, the notifications can be sent to other devices. Additionally, for example, it has a function to change the display method according to the ambient light level. This reduces the power consumption of the smartphone. Moreover, for example, images can be displayed on the smartphone in a way that allows for suitable use even in bright outdoor environments such as on a sunny day.

[0289] Figure 13B shows an electronic device that can use a remote control as an input unit 5240. As an example, a television system can be cited. For instance, data can be received from a radio station or the Internet and displayed on the display unit 5230. Additionally, a detection unit 5250 can capture images of the user. Furthermore, the user's image can be transmitted. Additionally, the user's viewing history can be obtained and provided to a cloud service. Furthermore, recommendation information can be obtained from the cloud service and displayed on the display unit 5230. Furthermore, programs or moving images can be displayed based on the recommendation information. Additionally, for example, it has a function to change the display method according to the ambient light level. Thus, images can be displayed on the television system in a way that allows for suitable use even in environments with strong outdoor light entering the room on sunny days.

[0290] Figure 13C shows an electronic device that can receive teaching materials from the Internet and display them on the display unit 5230. A tablet computer can be used as an example. Reports can be entered using the input unit 5240 and sent to the Internet. Furthermore, the grading results or evaluations of the reports can be obtained from cloud services and displayed on the display unit 5230. Additionally, appropriate teaching materials can be selected based on the evaluations and displayed on the display unit 5230.

[0291] For example, image signals can be received from other electronic devices and displayed on the display unit 5230. Alternatively, the display unit 5230 can be mounted on a stand or similar support and used as a secondary display. For example, images can be displayed on the tablet computer in a way that allows for suitable use of electronic devices even in bright outdoor environments such as on a sunny day.

[0292] Figure 13D shows an electronic device including multiple display units 5230. A digital camera can be cited as an example. For instance, an image captured using the detection unit 5250 can be displayed on the display unit 5230. Furthermore, the captured image can be displayed on the detection unit. Additionally, the captured image can be edited using the input unit 5240. Furthermore, text can be added to the captured image. Furthermore, it can be sent to the Internet. Additionally, it has a function to change shooting conditions according to the ambient light level. Thus, for example, the subject can be displayed on the digital camera in a way that allows for comfortable viewing even in bright outdoor environments such as on a sunny day.

[0293] Figure 13E illustrates an electronic device that can control other electronic devices by using other electronic devices as slaves and using the electronic device of this embodiment as a master. As an example, a portable personal computer can be cited. For instance, a portion of the image data can be displayed on the display unit 5230, and another portion of the image data can be displayed on the display unit of another electronic device. Furthermore, an image signal can be supplied. Additionally, data written from the input unit of another electronic device can be obtained using the communication unit 5290. Thus, for example, a portable personal computer can be used to utilize a larger display area.

[0294] Figure 14A shows an electronic device including a detection unit 5250 that detects acceleration or orientation. An example of this could be a goggle-type electronic device. The detection unit 5250 can provide data on the user's position or the direction the user is facing. Furthermore, the electronic device can generate image data for the right eye and image data for the left eye based on the user's position or the direction the user is facing. Additionally, the display unit 5230 includes a display area for the right eye and a display area for the left eye. Thus, for example, a realistic virtual reality space image can be displayed on the goggle-type electronic device.

[0295] Figure 14B shows an electronic device including a camera and a detection unit 5250 for detecting acceleration or orientation. An example of this could be an eyeglass-type electronic device. The detection unit 5250 can provide data on the user's position or the direction the user is facing. Furthermore, the electronic device can generate image data based on the user's position or the direction the user is facing. Thus, for example, data can be added to and displayed on a real-world landscape. Additionally, images of augmented reality can be displayed on the eyeglass-type electronic device.

[0296] Note that this embodiment can be appropriately combined with other embodiments shown in this specification.

[0297] Implementation Method 6 In this embodiment, the structure of using the light-emitting device shown in Embodiment 2 in a lighting device will be described with reference to FIGS. 15A and 15B. Note that FIG. 15A is a cross-sectional view along line segment ef in the top view of the lighting device shown in FIG. 15B.

[0298] In the lighting device of this embodiment, a first electrode 401 is formed on a light-transmitting substrate 400, which serves as a support. The first electrode 401 corresponds to the first electrode 101 in Embodiment 2. When light is extracted from the first electrode 401 side, the first electrode 401 is formed using a light-transmitting material.

[0299] Additionally, a pad 412 for supplying voltage to the second electrode 404 is formed on the substrate 400.

[0300] An EL layer 403 is formed on the first electrode 401. The EL layer 403 corresponds to the structure of the EL layer 103 in Embodiment 2. Note that their structures are described in the respective descriptions.

[0301] A second electrode 404 is formed by covering the EL layer 403. The second electrode 404 corresponds to the second electrode 102 in Embodiment 2. When light is extracted from the first electrode 401 side, the second electrode 404 is formed using a material with high reflectivity. Voltage is supplied to the second electrode 404 by connecting it to the pad 412.

[0302] As described above, the lighting device shown in this embodiment includes a light-emitting device comprising a first electrode 401, an EL layer 403, and a second electrode 404. Since this light-emitting device is a high-efficiency light-emitting device, the lighting device of this embodiment can be a low-power lighting device.

[0303] The light-emitting device having the above-described structure is formed on a substrate 400 and a sealing substrate 407, which are fixed together using sealing materials 405 and 406, thereby manufacturing a lighting device. Alternatively, only one of the sealing materials 405 and 406 may be used. Furthermore, the inner sealing material 406 (not shown in FIG. 15B) may be mixed with a desiccant, thereby absorbing moisture and improving reliability.

[0304] Furthermore, by providing pads 412 and a portion of the first electrode 401 that extend to the exterior of the sealing materials 405 and 406, they can be used as external input terminals. Additionally, an IC chip 420, on which a converter or similar device is mounted, can also be provided on the external input terminal.

[0305] Implementation Method 7 In this embodiment, an application example of a lighting device manufactured using a light-emitting device or a light-emitting device to which an embodiment of the present invention is applied will be described with reference to FIG16.

[0306] As an indoor lighting fixture, the 8001 ceiling spotlight can be used. The 8001 ceiling spotlight is available in direct-mount or recessed types. This lighting fixture is manufactured by combining a light-emitting device with a housing or cover. In addition, it can also be used in pendant lights (lighting fixtures suspended from the ceiling by wires).

[0307] In addition, the 8002 floor lamp illuminates the ground, improving safety underfoot. It is effective, for example, in bedrooms, staircases, or hallways. In such cases, the size or shape of the floor lamp can be appropriately adjusted according to the size or structure of the room. Furthermore, the 8002 floor lamp can also be a mounted lighting device formed by combining a light-emitting device and a bracket.

[0308] Furthermore, the 8003 sheet lighting device is a thin-film lighting device. Because it is used by attaching it to the wall, it does not take up space and can be applied to various purposes. In addition, it is easy to achieve large-area coverage. Furthermore, it can also be attached to curved walls or enclosures.

[0309] Alternatively, a lighting device 8004 can be used where light from a light source is controlled to travel only in the desired direction.

[0310] The desk lamp 8005 includes a light source 8006, which can be a light-emitting device or a part thereof of an embodiment of the present invention.

[0311] By using a light-emitting device of one embodiment of the present invention or a light-emitting element thereof in a part of indoor furniture other than those described above, a lighting device with furniture functions can be provided.

[0312] As described above, a wide variety of lighting devices suitable for light-emitting devices can be obtained. Furthermore, such lighting devices are included in one embodiment of the present invention.

[0313] The structure shown in this embodiment can be implemented by appropriately combining it with the structures shown in other embodiments.

[0314] Implementation Method 8 In this embodiment, a light-emitting device and a light-receiving device that can be used in one embodiment of the present invention will be described with reference to FIGS. 28A to 28C.

[0315] Figure 28A shows a cross-sectional schematic diagram of the light-emitting device 805a and the light-receiving device 805b included in a display device 810 according to an embodiment of the present invention.

[0316] The light-emitting device 805a has the function of emitting light (hereinafter also referred to as light-emitting function). The light-emitting device 805a includes an electrode 801a, an EL layer 803a, and an electrode 802. The light-emitting device 805a is preferably a light-emitting device (organic EL device) utilizing an organic EL, as shown in Embodiment 2. Therefore, the EL layer 803a sandwiched between the electrode 801a and the electrode 802 includes at least a light-emitting layer. The light-emitting layer contains a light-emitting material. By applying a voltage between the electrode 801a and the electrode 802, light is emitted from the EL layer 803a. In addition to the light-emitting layer, the EL layer 803a also includes various layers such as a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, a carrier (hole or electron) barrier layer, and a charge generation layer. Note that the EL layer 803a of the light-emitting device 805a can use a hybrid material for light-emitting devices according to one embodiment of the present invention.

[0317] The light-receiving device 805b has the function of detecting light (hereinafter also referred to as the light-receiving function). The light-receiving device 805b can, for example, use a pn-type or pin-type photodiode. The light-receiving device 805b includes an electrode 801b, a light-receiving layer 803b, and an electrode 802. The light-receiving layer 803b, sandwiched between the electrodes 801b and 802, includes at least an active layer. The light-receiving device 805b is used as a photoelectric conversion device, which can generate charge from light incident on the light-receiving layer 803b, thereby extracting it as current. At this time, a voltage can also be applied between the electrodes 801b and 802. The amount of charge generated depends on the amount of light incident on the light-receiving layer 803b.

[0318] The light-receiving device 805b has the function of detecting visible light. The light-receiving device 805b is sensitive to visible light. More preferably, the light-receiving device 805b has the function of detecting both visible and infrared light. The light-receiving device 805b is preferably sensitive to both visible and infrared light.

[0319] Note that in this specification, the wavelength region of blue (B) refers to 400 nm or more and less than 490 nm, and blue (B) light has at least one emission spectral peak in this wavelength region. Similarly, the wavelength region of green (G) refers to 490 nm or more and less than 580 nm, and green (G) light has at least one emission spectral peak in this wavelength region. Furthermore, the wavelength region of red (R) refers to 580 nm or more and less than 700 nm, and red (R) light has at least one emission spectral peak in this wavelength region. Additionally, in this specification, the wavelength region of visible light refers to 400 nm or more and less than 700 nm, and visible light has at least one emission spectral peak in this wavelength region. Furthermore, the wavelength region of infrared (IR) refers to 700 nm or more and less than 900 nm, and infrared (IR) light has at least one emission spectral peak in this wavelength region.

[0320] The active layer of the light-receiving device 805b contains a semiconductor. Examples of such semiconductors include inorganic semiconductors such as silicon and organic semiconductors containing organic compounds. Preferably, the light-receiving device 805b is an organic semiconductor device (or organic photodiode) in which the active layer contains an organic semiconductor. Organic photodiodes are easily made thin, lightweight, and large-area, and offer high flexibility in shape and design, making them suitable for a wide variety of display devices. Furthermore, by using an organic semiconductor, the EL layer 803a of the light-emitting device 805a and the active layer of the light-receiving device 805b can be formed using the same method (e.g., vacuum evaporation), allowing the use of a common manufacturing apparatus, which is therefore preferable. Note that the active layer of the light-receiving device 805b can use a hybrid material for organic semiconductor devices according to one embodiment of the present invention.

[0321] In one embodiment of the present invention, the display device can appropriately use an organic EL device and an organic photodiode as the light-emitting device 805a and the light-receiving device 805b, respectively. The organic EL device and the organic photodiode can be formed on the same substrate. Therefore, an organic photodiode can be built into a display device using an organic EL device. In addition to the function of displaying images, the display device of one embodiment of the present invention also has one or both of the functions of imaging and sensing.

[0322] Electrodes 801a and 801b are disposed on the same surface. Figure 28A shows the structure of electrodes 801a and 801b disposed on substrate 800. Note that electrodes 801a and 801b can be formed, for example, by processing a conductive film formed on substrate 800 into an island shape. That is, electrodes 801a and 801b can be formed by the same process.

[0323] The substrate 800 can be a substrate with heat resistance capable of withstanding the formation of the light-emitting device 805a and the light-receiving device 805b. When using an insulating substrate as the substrate 800, glass substrates, quartz substrates, sapphire substrates, ceramic substrates, organic resin substrates, etc., can be used. In addition, single-crystal semiconductor substrates or polycrystalline semiconductor substrates made of materials such as silicon or silicon carbide, compound semiconductor substrates made of materials such as silicon and germanium, SOI substrates, etc., can also be used.

[0324] In particular, the substrate 800 is preferably a substrate on which a semiconductor circuit including semiconductor elements such as transistors is formed on the aforementioned insulating substrate or semiconductor substrate. This semiconductor circuit is preferably, for example, a pixel circuit, a gate line drive circuit (gate driver), a source line drive circuit (source driver), etc. Furthermore, in addition to the above, it can also be configured as an arithmetic circuit, a memory circuit, etc.

[0325] Furthermore, electrode 802 is an electrode formed from a common layer in light-emitting device 805a and light-receiving device 805b. The electrode on the side emitting or incident light uses a conductive film that transmits visible and infrared light. The electrode on the side that does not emit or incident light preferably uses a conductive film that reflects visible and infrared light.

[0326] In one embodiment of the present invention, electrode 802 of the display device is used as one electrode of each of the light-emitting device 805a and the light-receiving device 805b.

[0327] Figure 28B shows the case where the potential of electrode 801a in the light-emitting device 805a is higher than that of electrode 802. In this case, electrode 801a is used as the anode of the light-emitting device 805a, and electrode 802 is used as the cathode. Furthermore, the potential of electrode 801b in the light-receiving device 805b is lower than that of electrode 802. Note that in Figure 28B, to easily understand the direction of current flow, the circuit symbol of the light-emitting diode is shown on the left side of the light-emitting device 805a, and the circuit symbol of the photodiode is shown on the right side of the light-receiving device 805b. Additionally, arrows schematically indicate the direction of carrier (electron and hole) flow in each device.

[0328] In the structure shown in Figure 28B, in the light-emitting device 805a, when electrode 801a is supplied with a first potential through a first wiring, electrode 802 is supplied with a second potential through a second wiring, and electrode 801a is supplied with a third potential through a third wiring, the magnitude relationship of each potential satisfies the condition that the first potential > the second potential > the third potential.

[0329] Figure 28C shows the case where the potential of electrode 801a in the light-emitting device 805a is lower than that of electrode 802. In this case, electrode 801a is used as the cathode of the light-emitting device 805a, and electrode 802 is used as the anode. Furthermore, the potential of electrode 801b in the light-receiving device 805b is lower than that of electrode 802 but higher than that of electrode 801a. Note that in Figure 28C, to easily understand the direction of current flow, the circuit symbol of the light-emitting diode is shown on the left side of the light-emitting device 805a, and the circuit symbol of the photodiode is shown on the right side of the light-receiving device 805b. Additionally, arrows schematically indicate the direction of carrier (electron and hole) flow in each device.

[0330] In the structure shown in Figure 28C, in the light-emitting device 805a, when electrode 801a is supplied with a first potential through a first wiring, electrode 802 is supplied with a second potential through a second wiring, and electrode 801a is supplied with a third potential through a third wiring, the magnitude relationship of each potential satisfies the condition that the second potential > the third potential > the first potential.

[0331] Note that the resolution of the light-receiving device 805b shown in this embodiment can be 100 ppi or higher, preferably 200 ppi or higher, more preferably 300 ppi or higher, further preferably 400 ppi or higher, and even more preferably 500 ppi or higher, but can be 2000 ppi or lower, 1000 ppi or lower, or 600 ppi or lower. In particular, by configuring the light-receiving device 805b with a resolution of 200 ppi or higher and 600 ppi or lower, preferably 300 ppi or higher and 600 ppi or lower, it can be appropriately used for fingerprint imaging. When performing fingerprint recognition using the display device according to one embodiment of the present invention, by improving the resolution of the light-receiving device 805b, for example, the fingerprint feature points (minutia) can be extracted with high precision, thereby improving the accuracy of fingerprint recognition. Furthermore, when the resolution is 500 ppi or higher, it can meet the specifications of the National Institute of Standards and Technology (NIST), etc., and is therefore preferred. Note that, assuming a resolution of 500 ppi for the light-receiving device, the size of each pixel is 50.8 μm, which confirms that sufficient resolution is available for capturing the spacing of fingerprint ridges (typically above 300 μm and below 500 μm). Example 1

[0332] In this embodiment, one or two materials are deposited on a glass substrate to create samples with different film structures (single-layer film, multilayer film, hybrid film, etc.), and heat resistance tests are performed on each sample. Furthermore, Table 1 shows the thermophysical properties of the materials used in this embodiment, and the chemical formulas are shown below.

[0333] [Table 1]

[0334] [Chemical Formula 5]

[0335] Next, the manufacturing method of the samples (sample 1 to sample 4) is shown.

[0336] First, a sample layer was formed on a glass substrate using a vacuum evaporation apparatus, and then cut into 2cm × 2cm squares to obtain the sample. Next, the sample was placed in a bell-type heater (BV-001 bell-type vacuum furnace manufactured by Shibata Scientific Co., Ltd.), the pressure was reduced to approximately 10 hPa, and then calcined for 1 hour within a temperature set range of 80°C to 150°C. After 1 hour, the substrate was cooled to 40°C and exposed to the atmosphere, and then the sample was removed using tweezers.

[0337] The sample layer of Sample 1 is formed by depositing a monolayer of a heteroaryrheic compound, 2,9-bis(2-naphthyl)-4,7-diphenyl-1,10-phenanthroline (abbreviated as NBPhen), on a glass substrate with a thickness of 10 nm.

[0338] The sample layer of Sample 2 is formed by evaporating a monolayer film of a heteroaromatic compound, 2-[4'-(9-phenyl-9H-carbazol-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoline (abbreviated as: 2mpPCBPDBq), on a glass substrate with a thickness of 10 nm.

[0339] The sample layer of sample 3 is formed by depositing a 10nm thick 2mpPCBPDBq on a glass substrate and then depositing a 10nm thick NBPhen.

[0340] The sample layer of sample 4 is a single-layer film composed of a mixture of multiple heteroaryrheic compounds. It is formed by co-depositing 2mpPCBPDBq and NBPhen on a glass substrate in a weight ratio of 0.5:0.5 (=2mpPCBPDBq:NBPhen) and a thickness of 20nm.

[0341] Each sample prepared by the above method was observed visually and using an optical microscope (MX61L semiconductor / FPD inspection microscope manufactured by Olympus Corporation).

[0342] Figures 17A to 17D show photographs of the samples manufactured in this embodiment (magnified 100x for dark-field observation).

[0343] Table 2 below shows the structures of each sample and the results based on Figures 17A to 17D. Note that in Table 2, circles indicate no crystallization (no crystallization), triangles indicate slight crystallization (slightly crystallized), and X symbols indicate crystallization (crystallized).

[0344] [Table 2]

[0345] The results above show that in a single film of a heteroaromatic compound (sample 1 NBPhen), crystallization does not occur before reaching a high temperature (crystallization begins around 140°C), resulting in a thin film with good heat resistance. However, when forming a multilayer film (sample 3 2mpPCBPDBq\NBPhen), crystallization occurs at a low temperature (100°C). In contrast, in a single film formed by mixing two heteroaromatic compounds (sample 4 2mpPCBPDBq:NBPhen), crystallization does not occur before reaching a high temperature (150°C), compared to the multilayer film (sample 3 2mpPCBPDBq\NBPhen) and the single film (sample 1 NBPhen).

[0346] In other words, it can be seen that: even if the monolayer film of the mixed material formed by mixing multiple heteroaromatic compounds in one embodiment of the present invention includes materials that crystallize at low temperatures when the monolayer film is composed of only one material, the monolayer film is formed by mixing multiple materials, which has the effect of increasing the crystallization temperature. Therefore, it can be seen that: even if the mixed material composed of multiple heteroaromatic compounds in one embodiment of the present invention includes materials with low crystallization temperatures of the monolayer film, the heat resistance can be improved.

[0347] In the results shown in Table 2, both Sample 1 (NBPhen) and Sample 2 (2mpPCBPDBq), formed as monolayers of NBPhen and 2mpPCBPDBq used in this embodiment, crystallized at temperatures lower than the glass transition temperature (Tg) shown in Table 1. In other words, crystallization, which typically does not occur when the thickness is reduced to the level required to form a light-emitting device or organic semiconductor device (thicknesses thinner than 1 μm, such as organic thin films 1 nm to 100 nm thick), occurred at temperatures lower than the glass transition temperature. Furthermore, Sample 3 (2mpPCBPDBq\NBPhen), a multilayer film, crystallized at an even lower temperature (100 °C). That is, it was confirmed that the intermolecular interaction between 2mpPCBPDBq and NBPhen promotes crystallization at temperatures lower than Tg. In contrast, it can be seen that the monolayer formed by mixing the two heteroaromatic compounds (Sample 4 2mpPCBPDBq:NBPhen) is not affected by 2mpPCBPDBq, and the film does not crystallize even when heat resistance tests are performed at high temperatures (150 °C).

[0348] Therefore, as an embodiment of the present invention, the mixed material composed of multiple heteroaromatic compounds can suppress the crystallization of the heteroaromatic compounds at temperatures below Tg, and can maintain a stable glassy film during thin-film formation. Thus, it can be considered a material with high heat resistance. By using such a heat-resistant film, heat-resistant light-emitting devices or organic semiconductor devices can be provided. Example 2

[0349] In this embodiment, one or two materials are deposited on a glass substrate to create samples with different film structures (single-layer films or hybrid films, etc.), and heat resistance tests are performed on each sample. Furthermore, Table 3 shows the thermophysical properties of the materials used in this embodiment, and the chemical formulas are shown below.

[0350] [Table 3]

[0351] [Chemical Formula 6]

[0352] Next, the manufacturing method of the samples (samples 5 to 7) is shown.

[0353] First, a sample layer was formed on a glass substrate using a vacuum evaporation apparatus, and then cut into 2cm × 2cm squares to obtain the sample. Next, the sample was placed in a bell-type heater (BV-001 bell-type vacuum furnace manufactured by Shibata Scientific Co., Ltd.), the pressure was reduced to approximately 10 hPa, and then calcined for 1 hour within a temperature set range of 80°C to 150°C. After 1 hour, the substrate was cooled to 40°C and exposed to the atmosphere, and then the sample was removed using tweezers.

[0354] The sample layer of sample 5 is formed by evaporating 2-{4-[9,10-bis(2-naphthyl)-2-anthrayl]phenyl}-1-phenyl-1H-benzimidazole (abbreviated as ZADN) on a glass substrate with a thickness of 25 nm using a monolayer film of a heteroaryrheic compound.

[0355] The sample layer of sample 6 is formed by evaporating a monolayer of a heteroaromatic compound, 2-[3'-(9,9-dimethyl-9H-furo-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviated as mFBPTzn), on a glass substrate with a thickness of 5 nm.

[0356] The sample layer of sample 7 is a monolayer film composed of a mixture of multiple heteroaryrheic compounds. It is formed by co-depositing mFBPTzn and ZADN on a glass substrate in a weight ratio of 0.5:0.5 (=mFBPTzn:ZADN) and a thickness of 5nm.

[0357] Each sample prepared by the above method was observed visually and using an optical microscope (MX61L semiconductor / FPD inspection microscope manufactured by Olympus Corporation).

[0358] Figures 18A to 18C show photographs of the samples manufactured in this embodiment (magnified 100x for dark-field observation).

[0359] Table 4 below shows the structures of each sample and the results based on Figures 18A to 18C. Note that in Table 4, circles indicate no crystallization (no crystallization), triangles indicate slight crystallization (slightly crystallized), and X symbols indicate crystallization (crystallized).

[0360] [Table 4]

[0361] The results above show that although the monolayer of heteroaromatic compounds (sample 5 ZADN) did not crystallize at high temperatures (150℃) and could form a thin film with good heat resistance, the monolayer of heteroaromatic compounds (sample 6 mFBPTzn) crystallized entirely at low temperatures (above 100℃). In contrast, the monolayer formed by mixing the two heteroaromatic compounds (sample 7 mFBPTzn:ZADN) was unaffected by mFBPTzn and did not crystallize even during heat resistance testing at high temperatures (150℃).

[0362] In other words, it can be seen that: even if the monolayer film of the mixed material formed by mixing multiple heteroaromatic compounds in one embodiment of the present invention includes materials that crystallize at low temperatures when the monolayer film is composed of only one material, the monolayer film is formed by mixing multiple materials, which has the effect of increasing the crystallization temperature. Therefore, it can be seen that: even if the mixed material composed of multiple heteroaromatic compounds in one embodiment of the present invention includes materials with low crystallization temperatures of the monolayer film, the heat resistance can be improved.

[0363] Therefore, as an embodiment of the present invention, the mixed material composed of multiple heteroaromatic compounds can suppress the crystallization of the heteroaromatic compounds at temperatures below Tg, and can maintain a stable glassy film during thin-film formation. Thus, it can be considered a material with high heat resistance. By using such a heat-resistant film, heat-resistant light-emitting devices or organic semiconductor devices can be provided. Example 3

[0364] In this embodiment, one or two materials are deposited on a glass substrate to create samples with different film structures (single-layer films or hybrid films, etc.), and heat resistance tests are performed on each sample. Furthermore, Table 5 shows the thermophysical properties of the materials used in this embodiment, and the chemical formulas are shown below.

[0365] [Table 5]

[0366] [Chemical Formula 7]

[0367] Next, the manufacturing method of the samples (samples 8 to 10) is shown.

[0368] First, a sample layer was formed on a glass substrate using a vacuum evaporation apparatus, and then cut into 2cm × 2cm squares to obtain the sample. Next, the sample was placed in a bell-type heater (BV-001 bell-type vacuum furnace manufactured by Shibata Scientific Co., Ltd.), the pressure was reduced to approximately 10 hPa, and then calcined for 1 hour within a temperature set range of 80°C to 150°C. After 1 hour, the substrate was cooled to 40°C and exposed to the atmosphere, and then the sample was removed using tweezers.

[0369] The sample layer of sample 8 is formed by depositing NBPhen on a glass substrate with a thickness of 10 nm using a monolayer film of a heteroaromatic compound.

[0370] The sample layer of sample 9 is formed by evaporating 2,4,6-tris(3'-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine (abbreviated as TmPPPyTz) on a glass substrate with a thickness of 35 nm using a monolayer film of a heteroaromatic compound.

[0371] The sample layer of sample 10 is a single-layer film composed of a mixture of multiple heteroaryl aromatic compounds. TmPPPyTz and NBPhen are co-deposited on a glass substrate in a weight ratio of 1:1 (=TmPPPyTz:NBPhen) and a thickness of 35nm.

[0372] Each sample prepared by the above method was observed visually and using an optical microscope (MX61L semiconductor / FPD inspection microscope manufactured by Olympus Corporation).

[0373] Figures 19A to 19C show photographs of the samples manufactured in this embodiment (magnified 100x for dark-field observation).

[0374] Table 6 below shows the structure of each sample and the results based on Figures 19A to 19C. Note that in Table 6, circles indicate no crystal formation (no crystallization), white triangles indicate slight crystallization (slightly crystallized), × indicates crystal formation (crystallized), and black triangles indicate crystallization only at the edges (crystallized only at the edges).

[0375] [Table 6]

[0376] The results above show that although the monolayer of heteroaromatic compounds (sample 8 NBPhen) did not crystallize at high temperatures (130℃) and could form a thin film with good heat resistance, the edges (ends) of the monolayer of heteroaromatic compounds (sample 9 TmPPPyTz) crystallized at low temperatures (above 100℃). In contrast, the monolayer formed by mixing the two heteroaromatic compounds (sample 10 TmPPPyTz:NBPhen) was unaffected by TmPPPyTz and did not crystallize even during heat resistance testing at high temperatures (150℃).

[0377] In other words, it can be seen that: even if the monolayer film of the mixed material formed by mixing multiple heteroaromatic compounds in one embodiment of the present invention includes materials that crystallize at low temperatures when the monolayer film is composed of only one material, the monolayer film is formed by mixing multiple materials, which has the effect of increasing the crystallization temperature. Therefore, it can be seen that: even if the mixed material composed of multiple heteroaromatic compounds in one embodiment of the present invention includes materials with low crystallization temperatures of the monolayer film, the heat resistance can be improved.

[0378] In the results shown in Table 6, the monofilm of the heteroaromatic compound (sample 8 NBPhen) crystallized at a temperature lower than the glass transition temperature (Tg) shown in Table 5. In other words, crystallization, which typically does not occur when the thickness is reduced to the level required to form a light-emitting device or organic semiconductor device (thicknesses thinner than 1 μm, such as organic thin films from 1 nm to 100 nm thick), occurs at temperatures lower than the glass transition temperature. In contrast, it can be seen that the monofilm formed by mixing the two heteroaromatic compounds mentioned above (sample 10 TmPPPyTz:NBPhen) is not affected by TmPPPyTz, and the film does not crystallize even when subjected to heat resistance tests at high temperatures (150 °C). This temperature is significantly higher than the glass transition temperature (Tg) of TmPPPyTz.

[0379] Therefore, as an embodiment of the present invention, the mixed material composed of multiple heteroaromatic compounds can suppress the crystallization of the heteroaromatic compounds at temperatures below Tg, and can maintain a stable glassy film during thin-film formation. Thus, it can be considered a material with high heat resistance. By using such a heat-resistant film, heat-resistant light-emitting devices or organic semiconductor devices can be provided. Example 4

[0380] The results of Example 3 show that the heat resistance of the monolayer film formed by the light-emitting device hybrid material according to one embodiment of the present invention is improved compared to that formed by a single material constituting the light-emitting device hybrid material. Therefore, the following light-emitting devices were manufactured and their characteristics were compared: light-emitting device 1 using the light-emitting device hybrid material according to one embodiment of the present invention as the electron transport layer, and comparative light-emitting devices 2 and 3 using a single material constituting the light-emitting device hybrid material as the electron transport layer. The element structures and their characteristics are described below. Table 7 shows the specific structures of light-emitting device 1, comparative light-emitting device 2, and comparative light-emitting device 3 used in this embodiment. Furthermore, the chemical formulas of the materials used in this embodiment are shown below.

[0381] [Table 7]

[0382] [Chemical Formula 8]

[0383] <<Manufacturing of Various Light-Emitting Devices>> As shown in Figure 20, each light-emitting device in this embodiment has the following structure: a hole injection layer 911, a hole transport layer 912, a light-emitting layer 913, an electron transport layer 914 and an electron injection layer 915 are sequentially stacked on a first electrode 901 formed on a substrate 900, and a second electrode 903 is stacked on the electron injection layer 915.

[0384] First, a first electrode 901 is formed on a substrate 900. The electrode area is 4 mm² (2 mm × 2 mm). A glass substrate is used as the substrate 900. Furthermore, the first electrode 901 is formed by sputtering an indium tin oxide (ITSO) containing silicon oxide with a thickness of 70 nm.

[0385] Here, as a pretreatment, the surface of the substrate is washed with water, calcined at 200°C for 1 hour, and then subjected to UV ozone treatment for 370 seconds. Then, the substrate is placed in a vacuum evaporation apparatus whose internal pressure is reduced to about 10⁻⁴ Pa, and calcined at 170°C for 60 minutes in the heating chamber of the vacuum evaporation apparatus, and then cooled for about 30 minutes.

[0386] Next, a hole injection layer 911 is formed on the first electrode 901. After being depressurized to 10⁻⁴ Pa in a vacuum evaporation apparatus, the hole injection layer 911 is formed by co-evaporation of N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-furo-2-amine (abbreviated as: PCBBiF) represented by the above structural formula (i) and an electron acceptor material (OCHD-003) containing fluorine with a molecular weight of 672 at a weight ratio of 1:0.03 (=PCBBiF:OCHD-003) and a thickness of 10 nm.

[0387] Next, a hole transport layer 912 is formed on the hole injection layer 911. After evaporation with PCBiF at a thickness of 40 nm, a hole transport layer 912 is formed by evaporation with 4,4'-diphenyl-4”-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as: PCBi1BP) at a thickness of 10 nm.

[0388] Next, a light-emitting layer 913 is formed on the hole transport layer 912.

[0389] The luminescent layer 913 was formed by co-evaporation of 8-(1,1'-biphenyl-4-yl)-4-[3-(dibenzothiophene-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviated as: 8BP-4mDBtPBfpm), 9-(2-naphthyl)-9'-phenyl-9H,9'H-3,3'-biscarbazole (abbreviated as: βNCCP) and bis[2-(2-pyridyl-κN)phenyl-κC][2-(4-phenyl-2-pyridyl-κN)phenyl-κC]iridium(III) (abbreviated as: [Ir(ppy) 2(4dppy)]) with a weight ratio of 8BP-4mDBtPBfpm:βNCCP:[Ir(ppy) 2(4dppy)]

[0390] Next, an electron transport layer 914 is formed on the light-emitting layer 913. Furthermore, in this embodiment, the electron transport layer 914 is shown to have a stacked structure of a first electron transport layer 914-1 and a second electron transport layer 914-2.

[0391] First, a first electron transport layer 914-1 of the light-emitting device 1 is formed by vapor deposition using 8BP-4mDBtPBfpm with a thickness of 10 nm. Then, a second electron transport layer 914-2 is formed by co-deposition of 2,4,6-tris(3'-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine (abbreviated as TmPPPyTz) and 2,9-bis(2-naphthyl)-4,7-diphenyl-1,10-phenanthroline (abbreviated as NBPhen) with a thickness of 20 nm in a weight ratio of TmPPPyTz:NBPhen=1:1.

[0392] The first electron transport layer 914-1 of the comparative light-emitting device 2 is formed by vapor deposition using 8BP-4mDBtPBfpm with a thickness of 10nm. Then, the second electron transport layer 914-2 is formed using NBPhen with a thickness of 20nm.

[0393] The first electron transport layer 914-1 of the comparative light-emitting device 3 was formed by vapor deposition using 8BP-4mDBtPBfpm with a thickness of 10nm. Then, the second electron transport layer 914-2 was formed using TmPPPyTz with a thickness of 20nm.

[0394] Next, an electron injection layer 915 is formed on the electron transport layer 914. The electron injection layer 915 is formed by evaporating lithium fluoride (LiF) with a thickness of 1 nm.

[0395] Next, a second electrode 903 is formed on the electron injection layer 915. The second electrode 903 is formed using aluminum by vapor deposition to a thickness of 200 nm. In this embodiment, the second electrode 903 is used as a cathode.

[0396] A light-emitting device 1, with an EL layer sandwiched between a pair of electrodes, is formed on a substrate 900 using the above-described process. Furthermore, the hole injection layer 911, hole transport layer 912, light-emitting layer 913, electron transport layer 914, and electron injection layer 915 described in the above process are functional layers constituting the EL layer in one embodiment of the present invention. Additionally, in the vapor deposition process of the above manufacturing method, resistance heating is used for vapor deposition.

[0397] The manufactured light-emitting device 1 was sealed in a glove box under a nitrogen atmosphere without being exposed to the atmosphere (a sealant was applied around the device, and UV treatment and heat treatment at 80°C for 1 hour were performed during sealing).

[0398] <<Operating Characteristics of Various Light-Emitting Devices>> Figure 21 shows the luminance-current density characteristics of light-emitting device 1, comparative light-emitting device 2, and comparative light-emitting device 3; Figure 22 shows the luminance-voltage characteristics; Figure 23 shows the current efficiency-luminance characteristics; Figure 24 shows the current-voltage characteristics; Figure 25 shows the external quantum efficiency-luminance characteristics; and Figure 26 shows the emission spectrum. Furthermore, Table 8 shows the main characteristics of light-emitting device 1, comparative light-emitting device 2, and comparative light-emitting device 3 near 1000 cd / m². Note that luminance, CIE chromaticity, and emission spectrum were measured at room temperature using a spectroradiometer (Topcon SR-UL1R).

[0399] [Table 8]

[0400] As can be seen from the results shown in Figures 21 to 26 and Table 8, the operating characteristics of the light-emitting device 1 in one embodiment of the present invention are equivalent to those of the comparative light-emitting device 2 and the comparative light-emitting device 3.

[0401] Next, reliability tests were conducted on each light-emitting device. Figure 27 shows the reliability test results for light-emitting device 1, comparison light-emitting device 2, and comparison light-emitting device 3. In Figure 27, the vertical axis represents the normalized brightness (%) when the initial brightness is 100%, and the horizontal axis represents the driving time (h) of the device. Note that, as a reliability test, each light-emitting device was driven at a constant current density of 50 mA / cm².

[0402] As can be seen from the results shown in Figure 27, the light-emitting device 1 of one embodiment of the present invention has the same excellent reliability as the comparative light-emitting device 2 and the comparative light-emitting device 3.

[0403] The above results show that the light-emitting device hybrid material in the light-emitting device 1 using an embodiment of the present invention in Example 3 exhibits high heat resistance. Compared with the comparative light-emitting devices 2 and 3, which use a single material constituting the light-emitting device hybrid material in the electron transport layer, the light-emitting device 1, which uses the light-emitting device hybrid material in the electron transport layer, has heat resistance in the manufacturing process.

[0404] 101: First electrode 102: Second electrode 103: EL layer 103a: EL layer 103b: EL layer 103B: EL layer 103G:EL layer 103R:EL layer 103P:EL layer 103Q:EL layer 104B: Hole Injection / Transmission Layer 104G: Hole Injection / Transmission Layer 104R: Hole Injection / Transmission Layer 104P: Hole Injection / Transmission Layer 104Q: Hole Injection / Transmission Layer 107: Insulation layer 107B: Insulation layer 107G: Insulation layer 107R: Insulation layer 108: Electron Transport Layer 108B: Electron Transport Layer 108G: Electron Transport Layer 108R: Electron transport layer 109: Electron Injection Layer 111: Hole Injection Layer 111a: Hole Injection Layer 111b: Hole Injection Layer 112: Hole Transport Layer 112a: Hole transport layer 112b: Hole transport layer 113: Emissive layer 113a: Emissive layer 113b: Emissive layer 113c: Emissive layer 114: Electron Transport Layer 115: Electron Injection Layer 231: Display area 400:Substrate 401: First electrode 403: EL layer 404: Second electrode 405: Sealant 406: Sealant 407:Sealing substrate 412: Solder pad 420: IC chip 501C: Insulating film 501D: Insulating film 504: Conductive film 506: Insulating film 508: Semiconductor film 508A: Area 508B: Area 508C: Area 510: First substrate 512A: Conductive film 512B: Conductive film 519:Terminal 516: Insulating film 516A: Insulating film 516B: Insulating film 518: Insulating film 520: Functional Layer 524: Conductive film 528: Partition Wall 530: Partition wall 530B: Pixel Circuit 530G: Pixel Circuit 550B: Light-emitting device 550G: Light-emitting device 550R: Light-emitting device 551B: Electrode 551G: Electrode 551R: Electrode 552: Electrode 580: Gap 591G: Opening 591B: Opening 700: Light-emitting device 702B: Pixel 702G: Pixels 702R: pixels 703: pixels 705: Insulation layer 770:Substrate 800:Substrate 801a, 801b: Electrodes 802: Electrode 803a, 803b: Electrodes 805a: Light-emitting device 805b: Light receiving device 810: Display device 900:Substrate 901: First electrode 903: Second electrode 911: Hole Injection Layer 912: Electric Hole Transport Layer 913: Emissive Layer 914: Electron Transport Layer 915: Electron Injection Layer 951:Substrate 952: Electrode 953: Insulation layer 954: Isolation Layer 955: EL layer 956: Electrode 5200B: Electronic Device 5210: Computing device 5220: Input / output device 5230: Display Unit 5240: Input Section 5250: Testing Department 5290: Communications Department 8001: Ceiling spotlight 8002: Ground Light 8003: Flake lighting 8004: Lighting equipment 8005: Desk Lamp 8006: Light source

Claims

1. A hybrid material for a light-emitting device, comprising: First heteroaromatic compound; And a second heteroaromatic compound, wherein the first heteroaromatic compound has a first heteroaromatic ring, the first heteroaromatic ring comprising a ring having two or more nitrogen atoms and any one of a benzene ring and a pyridine ring, or a ring having a diazine ring or a triazine ring, the second heteroaromatic compound has a second heteroaromatic ring, the second heteroaromatic ring comprising a ring having two or more nitrogen atoms and any one of a benzene ring and a pyridine ring, or a ring having a diazine ring or a triazine ring, and the structure of the first heteroaromatic ring is different from the structure of the second heteroaromatic ring.

2. The mixed material for the light-emitting device as claimed in claim 1, wherein either the first heteroaromatic ring or the second heteroaromatic ring is a fused heteroaromatic ring.

3. The mixed material for the light-emitting device as claimed in claim 1, wherein the first heteroaromatic ring and the second heteroaromatic ring are both fused heteroaromatic rings.

4. The mixed material for the light-emitting device as claimed in claim 1, wherein at least one of the first heteroaromatic ring and the second heteroaromatic ring is any one of a pyrimidine ring, a pyrazine ring, a diazonium ring, a triazine ring, a pyridine ring, a benzyline ring, a quinoline ring, a dibenzoquinoline ring, a quinazoline ring, a benzoquinazoline ring, a dibenzoquinazoline ring, a benzimidazole ring, a benzofuran-pyrimidine ring, and a benzofuran-pyrazine ring.

5. The hybrid material for the light-emitting device as claimed in claim 1, wherein the glass transition temperature of either the first heteroaromatic compound or the second heteroaromatic compound is 100°C or higher.

6. The hybrid material for the light-emitting device as claimed in claim 1, wherein the glass transition temperature of either the first heteroaromatic compound or the second heteroaromatic compound is 100°C or higher, and the difference between the glass transition temperature and the glass transition temperature of the other of the first heteroaromatic compound and the second heteroaromatic compound is 40°C or higher.

7. The hybrid material for the light-emitting device as claimed in claim 1, wherein the glass transition temperature of both the first heteroaromatic compound and the second heteroaromatic compound is above 100°C.